blob: 903e5b031826fd1a3ed45b81517960ff33384051 [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
Guido van Rossum7dab2422002-04-26 19:40:56 +00009- New builtin function enumerate(x), from PEP 279. Example:
10 enumerate("abc") is an iterator returning (0,"a"), (1,"b"), (2,"c").
11 The argument can be an arbitrary iterable object.
12
Neil Schemenauer89e3ee02002-04-26 01:58:53 +000013- The assert statement no longer tests __debug__ at runtime. This means
14 that assert statements cannot be disabled by assigning a false value
15 to __debug__.
16
Walter Dörwald068325e2002-04-15 13:36:47 +000017- A method zfill() was added to str and unicode, that fills a numeric
18 string to the left with zeros. For example,
19 "+123".zfill(6) -> "+00123".
20
Guido van Rossum862fe3c2002-04-15 12:36:47 +000021- Complex numbers supported divmod() and the // and % operators, but
22 these make no sense. Since this was documented, they're being
23 deprecated now.
24
Guido van Rossum26dd8302002-04-26 20:11:29 +000025- String and unicode methods lstrip(), rstrip() and strip() now take
26 an optional argument that specifies the characters to strip. For
27 example, "Foo!!!?!?!?".rstrip("?!") -> "Foo".
Guido van Rossum49042042002-04-13 00:59:05 +000028
Guido van Rossumc69343b2002-04-12 19:22:48 +000029- Added a new dict method pop(key). This removes and returns the
30 value corresponding to key. [SF patch #539949]
31
Guido van Rossum8ace1ab2002-04-06 01:05:01 +000032- Changed new-style class instantiation so that when C's __new__
33 method returns something that's not a C instance, its __init__ is
34 not called. [SF bug #537450]
35
Guido van Rossum181e41a2002-04-06 00:23:25 +000036- Fixed super() to work correctly with class methods. [SF bug #535444]
37
Guido van Rossum47834462002-04-04 15:21:33 +000038- A new built-in type, bool, has been added, as well as built-in
39 names for its two values, True and False. Comparisons and sundry
40 other operations that return a truth value have been changed to
41 return a bool instead. Read PEP 285 for an explanantion of why this
42 is backward compatible.
43
Guido van Rossum95b62a62002-03-29 01:07:24 +000044- Fixed two bugs reported as SF #535905: under certain conditions,
45 deallocating a deeply nested structure could cause a segfault in the
46 garbage collector, due to interaction with the "trashcan" code;
47 access to the current frame during destruction of a local variable
48 could access a pointer to freed memory.
49
Neil Schemenauer9d50d132002-03-22 17:06:59 +000050- The optional object allocator has been enabled by default.
51
Guido van Rossum8c842552002-03-14 23:05:54 +000052- If you try to pickle an instance of a class that has __slots__ but
53 doesn't define or override __getstate__, a TypeError is now raised.
54 This is done by adding a bozo __getstate__ to the class that always
55 raises TypeError. (Before, this would appear to be pickled, but the
56 state of the slots would be lost.)
57
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +000058- PyErr_Display will provide file and line information for all exceptions
59 that have an attribute print_file_and_line, not just SyntaxErrors.
60
Marc-André Lemburge92e0a92002-02-09 11:28:43 +000061- The UTF-8 codec will now encode and decode Unicode surrogates
62 correctly and without raising exceptions for unpaired ones.
63
Neal Norwitz649b7592002-01-01 19:07:13 +000064- file.xreadlines() now raises a ValueError if the file is closed:
65 Previously, an xreadlines object was returned which would raise
66 a ValueError when the xreadlines.next() method was called.
67
Martin v. Löwisb2c92f42002-02-16 23:35:41 +000068- posix.killpg has been added where available.
69
Neal Norwitz0c766a02002-03-27 13:03:09 +000070- sys.exit() inadvertantly allowed more than one argument.
71 An exception will now be raised if more than one argument is used.
72
Tim Petersaf8446f2001-12-21 21:36:50 +000073Extension modules
74
Tim Peters81b92512002-04-29 01:37:32 +000075- The bsddb.*open functions can now take 'None' as a filename.
Anthony Baxter83888952002-04-23 02:11:05 +000076 This will create a temporary in-memory bsddb that won't be
Tim Peters81b92512002-04-29 01:37:32 +000077 written to disk.
Anthony Baxter83888952002-04-23 02:11:05 +000078
Martin v. Löwis06a83e92002-04-14 10:19:44 +000079- posix.mknod was added.
80
Martin v. Löwis2e64c342002-03-27 18:49:02 +000081- The locale module now exposes the C library's gettext interface.
82
Tim Petersfbf74f22002-03-14 19:06:01 +000083- A security hole ("double free") was found in zlib-1.1.3, a popular
84 third party compression library used by some Python modules. The
85 hole was quickly plugged in zlib-1.1.4, and the Windows build of
86 Python now ships with zlib-1.1.4.
87
Martin v. Löwis688357e2002-04-08 21:28:20 +000088- pwd, grp, and resource return enhanced tuples now, with symbolic
89 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +000090
Martin v. Löwis99866332002-03-01 10:27:01 +000091- array.array is now a type object. A new format character
92 'u' indicates Py_UNICODE arrays. For those, .tounicode and
93 .fromunicode methods are available. Arrays now support __iadd__
94 and __imul__.
95
Neal Norwitze790eae2002-01-01 21:14:12 +000096- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +000097 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
98 is called.
99
Tim Petersaf8446f2001-12-21 21:36:50 +0000100Library
101
Tim Peters81b92512002-04-29 01:37:32 +0000102- difflib's SequenceMatcher class now does a dynamic analysis of
103 which elements are so frequent as to constitute noise. For
104 comparing files as sequences of lines, this generally works better
105 than the IS_LINE_JUNK function, and function ndiff's linejunk
106 argument defaults to None now as a result. A happy benefit is
107 that SequenceMatcher may run much faster now when applied
108 to large files with many duplicate lines (for example, C program
109 text with lots of repeated "}" and "return NULL;" lines).
110
Guido van Rossum256705b2002-04-23 13:29:43 +0000111- New Text.dump() method in Tkinter module.
112
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000113- New distutils commands for building packagers were added to
114 support pkgtool on Solaris and swinstall on HP-UX.
115
116- distutils now has a new abstract binary packager base class
117 command/bdist_packager, which simplifies writing packagers.
118 This will hopefully provide the missing bits to encourage
119 people to submit more packagers, e.g. for Debian, FreeBSD
120 and other systems.
121
Marc-André Lemburg4179a012002-04-05 12:15:05 +0000122- The UTF-16, -LE and -BE now raise a NotImplementedError
123 for all calls to .readline(). Previously, they used to just
124 produce garbage or fail with an encoding error -- UTF-16 is
125 a 2-byte encoding and the C lib's line reading APIs don't
126 work well with these.
127
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000128- compileall now supports quiet operation.
129
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000130- The BaseHTTPServer implements now optionally HTTP/1.1 persistent
131 connections.
132
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000133- socket module: the SSL support was broken out of the main
134 _socket module C helper and placed into a new _ssl helper
135 which now gets imported by socket.py if available and working.
136
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000137- encodings package: added aliases for all supported IANA character
138 sets
139
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000140- ftplib: to safeguard the user's privacy, anonymous login will use
141 "anonymous@" as default password, rather than the real user and host
142 name.
143
Fred Drake36736122002-01-10 13:50:31 +0000144- webbrowser: tightened up the command passed to os.system() so that
145 arbitrary shell code can't be executed because a bogus URL was
146 passed in.
147
Tim Peters11bd9942002-02-01 00:52:29 +0000148- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000149 gettext.find an optional all argument. Translations will now fallback
150 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000151
Martin v. Löwis9668b932002-01-12 11:27:42 +0000152- distutils bdist commands now offer a --skip-build option.
153
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000154- warnings.warn now accepts a Warning instance as first argument.
155
Fred Drakefed7e852002-04-04 19:36:15 +0000156- The xml.sax.expatreader.ExpatParser class will no longer create
157 circular references by using itself as the locator that gets passed
158 to the content handler implementation. [SF bug #535474]
159
Tim Petersaf8446f2001-12-21 21:36:50 +0000160Tools/Demos
161
Marc-André Lemburg46260092002-04-04 16:17:11 +0000162- freeze.py now produces binaries which can import shared modules,
163 unlike before when this failed due to missing symbol exports in
164 the generated binary.
165
Tim Petersaf8446f2001-12-21 21:36:50 +0000166Build
167
Tim Peters639295f2002-04-21 07:30:30 +0000168- XXX WITH_UNIVERSAL_NEWLINES Somebody fill this in; the PEP doesn't
169 say how or when to configure it, or how to turn it off.
170
Martin v. Löwis1142de32002-03-29 16:28:31 +0000171- On Unix, a shared libpython2.3.so can be created with --enable-shared.
172
Tim Peters8deda702002-03-30 10:06:07 +0000173- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
174 preprocessor symbols were eliminated. The internal decisions they
175 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000176
Tim Petersaf8446f2001-12-21 21:36:50 +0000177C API
178
Guido van Rossum517c7d42002-04-26 02:49:14 +0000179- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
180 coercion if both arguments have the same type but this type has the
181 CHECKTYPES flag set. This is to better support proxies.
182
Neil Schemenauer9344b142002-04-12 23:00:08 +0000183- The type of tp_free has been changed from "void (*)(PyObject *)" to
184 "void (*)(void *)".
185
186- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
187
Guido van Rossum0986d822002-04-08 01:38:42 +0000188- A type can now inherit its metatype from its base type. Previously,
189 when PyType_Ready() was called, if ob_type was found to be NULL, it
190 was always set to &PyType_Type; now it is set to base->ob_type,
191 where base is tp_base, defaulting to &PyObject_Type.
192
193- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
194
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000195- Objects allocated using the new PyMalloc_New and PyMalloc_NewVar
196 functions will be allocated using pymalloc if it is enabled. These
197 objects should be deallocated using PyMalloc_Del. The PyObject_{New,
198 NewVar,NEW_VAR,Del,DEL} APIs have been changed to always use
199 PyMem_MALLOC and PyMem_FREE, even if pymalloc is enabled. The
200 PyCore_* family of APIs have been removed.
201
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000202- The "u#" parser marker will now pass through Unicode object as-is
203 without going through the buffer API.
204
Martin v. Löwis7198a522002-01-01 19:59:11 +0000205- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
206
Tim Peters10a3bb52001-12-25 19:07:38 +0000207- An old #define of ANY as void has been removed from pyport.h. This
208 hasn't been used since Python's pre-ANSI days, and the #define has
209 been marked as obsolete since then. SF bug 495548 says it created
210 conflicts with other packages, so keeping it around wasn't harmless.
211
Tim Petersaf8446f2001-12-21 21:36:50 +0000212- Because Python's magic number scheme broke on January 1st, we decided
213 to stop Python development. Thanks for all the fish!
214
Tim Petersfb05db22002-03-11 00:24:00 +0000215- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000216 scheme to a new one. See Python/import.c for details.
217
Tim Petersaf8446f2001-12-21 21:36:50 +0000218New platforms
219
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000220- GNU/Hurd is now supported.
221
Tim Petersaf8446f2001-12-21 21:36:50 +0000222Tests
223
224Windows
225
Tim Peters08e72952002-04-16 20:48:01 +0000226- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
227 of that has been fixed in the installer (disabled Wise's "delete in-
228 use files" uninstall option).
229
Guido van Rossum181e41a2002-04-06 00:23:25 +0000230- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
231
Tim Peters33187922002-04-04 20:02:04 +0000232- The installer now installs Start menu shortcuts under (the local
233 equivalent of) "All Users" when doing an Admin install.
234
Tim Petersfb05db22002-03-11 00:24:00 +0000235- file.truncate([newsize]) now works on Windows for all newsize values.
236 It used to fail if newsize didn't fit in 32 bits, reflecting a
237 limitation of MS _chsize (which is no longer used).
238
Tim Petersab034fa2002-02-01 11:27:43 +0000239- os.waitpid() is now implemented for Windows, and can be used to block
240 until a specified process exits. This is similar to, but not exactly
241 the same as, os.waitpid() on POSIX systems. If you're waiting for
242 a specific process whose pid was obtained from one of the spawn()
243 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000244 See the docs for details. The docs were changed to clarify that
245 spawn functions return, and waitpid requires, a process handle on
246 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000247
Tim Peters11bd9942002-02-01 00:52:29 +0000248- New tempfile.TemporaryFile implementation for Windows: this doesn't
249 need a TemproraryFileWrapper wrapper anymore, and should be immune
250 to a nasty problem: before 2.3, if you got a temp file on Windows, it
251 got wrapped in an object whose close() method first closed the
252 underlying file, then deleted the file. This usually worked fine.
253 However, the spawn family of functions on Windows create (at a low C
254 level) the same set of open files in the spawned process Q as were
255 open in the spawning process P. If a temp file f was among them, then
256 doing f.close() in P first closed P's C-level file handle on f, but Q's
257 C-level file handle on f remained open, so the attempt in P to delete f
258 blew up with a "Permission denied" error (Windows doesn't allow
259 deleting open files). This was surprising, subtle, and difficult to
260 work around.
261
262- The os module now exports all the symbolic constants usable with the
263 low-level os.open() on Windows: the new constants in 2.3 are
264 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
265 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
266 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
267 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
268 (so specify both if you want both; note that neither is useful unless
269 specified with O_CREAT too).
270
Tim Petersaf8446f2001-12-21 21:36:50 +0000271Mac
272
273
Tim Peters909c0912001-12-14 23:16:18 +0000274What's New in Python 2.2 final?
275Release date: 21-Dec-2001
276===============================
277
278Type/class unification and new-style classes
279
Barry Warsaw52acb492001-12-21 20:04:22 +0000280- pickle.py, cPickle: allow pickling instances of new-style classes
281 with a custom metaclass.
282
Tim Peters909c0912001-12-14 23:16:18 +0000283Core and builtins
284
Barry Warsaw52acb492001-12-21 20:04:22 +0000285- weakref proxy object: when comparing, unwrap both arguments if both
286 are proxies.
287
Tim Peters909c0912001-12-14 23:16:18 +0000288Extension modules
289
Barry Warsaw52acb492001-12-21 20:04:22 +0000290- binascii.b2a_base64(): fix a potential buffer overrun when encoding
291 very short strings.
292
293- cPickle: the obscure "fast" mode was suspected of causing stack
294 overflows on the Mac. Hopefully fixed this by setting the recursion
295 limit much smaller. If the limit is too low (it only affects
296 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
297 when compiling cPickle.c (or in pyconfig.h).
298
Tim Peters909c0912001-12-14 23:16:18 +0000299Library
300
Barry Warsaw52acb492001-12-21 20:04:22 +0000301- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
302 close or delete time).
303
304- rfc822.py: fixed a bug where the address '<>' was converted to None
305 instead of an empty string (also fixes the email.Utils module).
306
307- xmlrpclib.py: version 1.0.0; uses precision for doubles.
308
309- test suite: the pickle and cPickle tests were not executing any code
310 when run from the standard regresssion test.
311
Tim Peters909c0912001-12-14 23:16:18 +0000312Tools/Demos
313
314Build
315
316C API
317
318New platforms
319
320Tests
321
322Windows
323
Barry Warsaw52acb492001-12-21 20:04:22 +0000324- distutils package: fixed broken Windows installers (bdist_wininst).
325
326- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
327 instances are deleted at process exit time.
328
329- socket.py: prevent mysterious warnings when socket instances are
330 deleted at process exit time.
331
332- posixmodule.c: fix a Windows crash with stat() of a filename ending
333 in backslash.
334
Tim Peters909c0912001-12-14 23:16:18 +0000335Mac
336
Barry Warsaw52acb492001-12-21 20:04:22 +0000337- The Carbon toolbox modules have been upgraded to Universal Headers
338 3.4, and experimental CoreGraphics and CarbonEvents modules have
339 been added. All only for framework-enabled MacOSX.
340
Tim Peters909c0912001-12-14 23:16:18 +0000341
Tim Peters6272dfd2001-12-13 19:34:00 +0000342What's New in Python 2.2c1?
343Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000344===========================
345
346Type/class unification and new-style classes
347
Barry Warsaw06557452001-12-14 20:47:12 +0000348- Guido's tutorial introduction to the new type/class features has
349 been extensively updated. See
350
351 http://www.python.org/2.2/descrintro.html
352
353 That remains the primary documentation in this area.
354
Guido van Rossum33bab012001-12-05 22:45:48 +0000355- Fixed a leak: instance variables declared with __slots__ were never
356 deleted!
357
Guido van Rossum4b800852001-12-03 00:54:52 +0000358- The "delete attribute" method of descriptor objects is called
359 __delete__, not __del__. In previous releases, it was mistakenly
360 called __del__, which created an unfortunate overloading condition
361 with finalizers. (The "get attribute" and "set attribute" methods
362 are still called __get__ and __set__, respectively.)
363
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000364- Some subtle issues with the super built-in were fixed:
365
366 (a) When super itself is subclassed, its __get__ method would still
367 return an instance of the base class (i.e., of super).
368
369 (b) super(C, C()).__class__ would return C rather than super. This
370 is confusing. To fix this, I decided to change the semantics of
371 super so that it only applies to code attributes, not to data
372 attributes. After all, overriding data attributes is not
373 supported anyway.
374
375 (c) The __get__ method didn't check whether the argument was an
376 instance of the type used in creation of the super instance.
377
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000378- Previously, hash() of an instance of a subclass of a mutable type
379 (list or dictionary) would return some value, rather than raising
380 TypeError. This has been fixed. Also, directly calling
381 dict.__hash__ and list.__hash__ now raises the same TypeError
382 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000383
Guido van Rossumd331cb52001-12-05 19:46:42 +0000384- New-style objects now support deleting their __dict__. This is for
385 all intents and purposes equivalent to assigning a brand new empty
386 dictionary, but saves space if the object is not used further.
387
Tim Petersb3c9af12001-11-17 00:21:57 +0000388Core and builtins
389
Tim Peters3caca232001-12-06 06:23:26 +0000390- -Qnew now works as documented in PEP 238: when -Qnew is passed on
391 the command line, all occurrences of "/" use true division instead
392 of classic division. See the PEP for details. Note that "all"
393 means all instances in library and 3rd-party modules, as well as in
394 your own code. As the PEP says, -Qnew is intended for use only in
395 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000396 Note that test_coercion.py in the standard Python test suite fails
397 under -Qnew; this is expected, and won't be repaired until true
398 division becomes the default (in the meantime, test_coercion is
399 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000400
Fred Drake6c01e252001-12-14 17:08:12 +0000401- complex() now only allows the first argument to be a string
402 argument, and raises TypeError if either the second arg is a string
403 or if the second arg is specified when the first is a string.
404
Tim Petersb3c9af12001-11-17 00:21:57 +0000405Extension modules
406
Martin v. Löwis560da622001-11-24 09:24:51 +0000407- gc.get_referents was renamed to gc.get_referrers.
408
Tim Petersb3c9af12001-11-17 00:21:57 +0000409Library
410
Tim Peters25059d32001-12-07 20:35:43 +0000411- Functions in the os.spawn() family now release the global interpreter
412 lock around calling the platform spawn. They should always have done
413 this, but did not before 2.2c1. Multithreaded programs calling
414 an os.spawn function with P_WAIT will no longer block all Python threads
415 until the spawned program completes. It's possible that some programs
416 relies on blocking, although more likely by accident than by design.
417
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000418- webbrowser defaults to netscape.exe on OS/2 now.
419
Martin v. Löwis652e1912001-11-25 14:50:56 +0000420- Tix.ResizeHandle exposes detach_widget, hide, and show.
421
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000422- The charset alias windows_1252 has been added.
423
Barry Warsaw06557452001-12-14 20:47:12 +0000424- types.StringTypes is a tuple containing the defined string types;
425 usually this will be (str, unicode), but if Python was compiled
426 without Unicode support it will be just (str,).
427
428- The pulldom and minidom modules were synchronized to PyXML.
429
Tim Petersb3c9af12001-11-17 00:21:57 +0000430Tools/Demos
431
Barry Warsaw06557452001-12-14 20:47:12 +0000432- A new script called Tools/scripts/google.py was added, which fires
433 off a search on Google.
434
Tim Petersb3c9af12001-11-17 00:21:57 +0000435Build
436
Barry Warsaw06557452001-12-14 20:47:12 +0000437- Note that release builds of Python should arrange to define the
438 preprocessor symbol NDEBUG on the command line (or equivalent).
439 In the 2.2 pre-release series we tried to define this by magic in
440 Python.h instead, but it proved to cause problems for extension
441 authors. The Unix, Windows and Mac builds now all define NDEBUG in
442 release builds via cmdline (or equivalent) instead. Ports to
443 other platforms should do likewise.
444
Jack Jansen1999ef42001-12-06 21:47:20 +0000445- It is no longer necessary to use --with-suffix when building on a
446 case-insensitive file system (such as Mac OS X HFS+). In the build
447 directory an extension is used, but not in the installed python.
448
Tim Petersb3c9af12001-11-17 00:21:57 +0000449C API
450
Tim Petersf582b822001-12-11 18:51:08 +0000451- New function PyDict_MergeFromSeq2() exposes the builtin dict
452 constructor's logic for updating a dictionary from an iterable object
453 producing key-value pairs.
454
Tim Peterscffed4b2001-11-29 03:26:37 +0000455- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000456 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000457 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
458 dump core in some bad cases. This has been repaired. As a result,
459 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
460 previously went unchallenged.
461
Tim Petersb3c9af12001-11-17 00:21:57 +0000462New platforms
463
464Tests
465
466Windows
467
468Mac
469
Jack Jansenffa260f2001-12-06 21:14:00 +0000470- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
471 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000472
Barry Warsaw06557452001-12-14 20:47:12 +0000473- Changed logic for finding python home in Mac OS X framework Pythons.
474 Now sys.executable points to the executable again, in stead of to
475 the shared library. The latter is used only for locating the python
476 home.
477
478
Tim Peters84362bc2001-10-19 17:55:30 +0000479What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000480Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000481===========================
482
483Type/class unification and new-style classes
484
Guido van Rossum3d27df02001-11-15 20:27:54 +0000485- Multiple inheritance mixing new-style and classic classes in the
486 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000487
488 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000489 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000490
491 The MRO (method resolution order) for each base class is respected
492 according to its kind, but the MRO for the derived class is computed
493 using new-style MRO rules if any base clase is a new-style class.
494 This needs to be documented.
495
Tim Petersa427a2b2001-10-29 22:25:45 +0000496- The new builtin dictionary() constructor, and dictionary type, have
497 been renamed to dict. This reflects a decade of common usage.
498
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000499- dict() now accepts an iterable object producing 2-sequences. For
500 example, dict(d.items()) == d for any dictionary d. The argument,
501 and the elements of the argument, can be any iterable objects.
502
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000503- New-style classes can now have a __del__ method, which is called
504 when the instance is deleted (just like for classic classes).
505
Guido van Rossum12d955c2001-10-26 14:56:06 +0000506- Assignment to object.__dict__ is now possible, for objects that are
507 instances of new-style classes that have a __dict__ (unless the base
508 class forbids it).
509
Guido van Rossumc8e56452001-10-22 00:43:43 +0000510- Methods of built-in types now properly check for keyword arguments
511 (formerly these were silently ignored). The only built-in methods
512 that take keyword arguments are __call__, __init__ and __new__.
513
Guido van Rossum86443212001-10-27 22:28:54 +0000514- The socket function has been converted to a type; see below.
515
Tim Peters84362bc2001-10-19 17:55:30 +0000516Core and builtins
517
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000518- Assignment to __debug__ raises SyntaxError at compile-time. This
519 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000520 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000521
Guido van Rossum12d955c2001-10-26 14:56:06 +0000522- Clarified the error messages for unsupported operands to an operator
523 (like 1 + '').
524
Tim Peters84362bc2001-10-19 17:55:30 +0000525Extension modules
526
Tim Peters5ebfd362001-11-13 23:11:19 +0000527- mmap has a new keyword argument, "access", allowing a uniform way for
528 both Windows and Unix users to create read-only, write-through and
529 copy-on-write memory mappings. This was previously possible only on
530 Unix. A new keyword argument was required to support this in a
531 uniform way because the mmap() signuatures had diverged across
532 platforms. Thanks to Jay T Miller for repairing this!
533
Tim Peters169ded02001-11-03 19:57:21 +0000534- By default, the gc.garbage list now contains only those instances in
535 unreachable cycles that have __del__ methods; in 2.1 it contained all
536 instances in unreachable cycles. "Instances" here has been generalized
537 to include instances of both new-style and old-style classes.
538
Guido van Rossum12d955c2001-10-26 14:56:06 +0000539- The socket module defines a new method for socket objects,
540 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000541 send() until all data has been sent. Also, the socket function has
542 been converted to a subclassable type, like list and tuple (etc.)
543 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000544
545- Various bugfixes to the curses module. There is now a test suite
546 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000547
Guido van Rossum692adf12001-10-30 03:03:03 +0000548- binascii.b2a_base64 no longer places an arbitrary restriction of 57
549 bytes on its input.
550
Tim Peters84362bc2001-10-19 17:55:30 +0000551Library
552
Tim Peters5ebfd362001-11-13 23:11:19 +0000553- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000554 convenience function.
555
Tim Peters75335872001-11-03 19:35:43 +0000556- Symbolic group names in regular expressions must be unique. For
557 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
558 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000559 Python 2.2 detects this error at regexp compilation time;
560 previously, the error went undetected, and results were
561 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
562 pattern.subn() methods have been rewritten in C. Also, an
563 experimental function/method finditer() has been added, which works
564 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000565
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000566- Tix exposes more commands through the classes DirSelectBox,
567 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
568 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
569 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
570
Tim Peters98791af2001-10-23 01:59:54 +0000571- Traceback objects are now scanned by cyclic garbage collection, so
572 cycles created by casual use of sys.exc_info() no longer cause
573 permanent memory leaks (provided garbage collection is enabled).
574
Guido van Rossum49192142001-10-24 20:51:44 +0000575- os.extsep -- a new variable needed by the RISCOS support. It is the
576 separator used by extensions, and is '.' on all platforms except
577 RISCOS, where it is '/'. There is no need to use this variable
578 unless you have a masochistic desire to port your code to RISCOS.
579
Barry Warsaw012852b2001-11-16 16:17:27 +0000580- mimetypes.py has optional support for non-standard, but commonly
581 found types. guess_type() and guess_extension() now accept an
582 optional `strict' flag, defaulting to true, which controls whether
583 recognize non-standard types or not. A few non-standard types we
584 know about have been added. Also, when run as a script, there are
585 new -l and -e options.
586
587- statcache is now deprecated.
588
589- email.Utils.formatdate() now produces the preferred RFC 2822 style
590 dates with numeric timezones (it used to produce obsolete dates
591 hard coded to "GMT" timezone). An optional `localtime' flag is
592 added to produce dates in the local timezone, with daylight savings
593 time properly taken into account.
594
595- In pickle and cPickle, instead of masking errors in load() by
596 transforming them into SystemError, we let the original exception
597 propagate out. Also, implement support for __safe_for_unpickling__
598 in pickle, as it already was supported in cPickle.
599
Tim Peters84362bc2001-10-19 17:55:30 +0000600Tools/Demos
601
602Build
603
Barry Warsaw012852b2001-11-16 16:17:27 +0000604- The dbm module is built using libdb1 if available. The bsddb module
605 is built with libdb3 if available.
606
607- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
608
Tim Peters84362bc2001-10-19 17:55:30 +0000609C API
610
Tim Peters1fc240e2001-10-26 05:06:50 +0000611- New function PySequence_Fast_GET_SIZE() returns the size of a non-
612 NULL result from PySequence_Fast(), more quickly than calling
613 PySequence_Size().
614
Barry Warsaw012852b2001-11-16 16:17:27 +0000615- New argument unpacking function PyArg_UnpackTuple() added.
616
617- New functions PyObject_CallFunctionObjArgs() and
618 PyObject_CallMethodObjArgs() have been added to make it more
619 convenient and efficient to call functions and methods from C.
620
621- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
622 possible that this will propagate errors it didn't before.
623
624- New function PyObject_CheckReadBuffer(), which returns true if its
625 argument supports the single-segment readable buffer interface.
626
Tim Peters84362bc2001-10-19 17:55:30 +0000627New platforms
628
Guido van Rossum86443212001-10-27 22:28:54 +0000629- We've finally confirmed that this release builds on HP-UX 11.00,
630 *with* threads, and passes the test suite.
631
Tim Peters7a33d8b2001-11-05 02:51:07 +0000632- Thanks to a series of patches from Michael Muller, Python may build
633 again under OS/2 Visual Age C++.
634
Guido van Rossum49192142001-10-24 20:51:44 +0000635- Updated RISCOS port by Dietmar Schwertberger.
636
Tim Peters84362bc2001-10-19 17:55:30 +0000637Tests
638
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000639- Added a test script for the curses module. It isn't run automatically;
640 regrtest.py must be run with '-u curses' to enable it.
641
Tim Peters84362bc2001-10-19 17:55:30 +0000642Windows
643
Barry Warsaw012852b2001-11-16 16:17:27 +0000644Mac
645
646- PythonScript has been moved to unsupported and is slated to be
647 removed completely in the next release.
648
649- It should now be possible to build applets that work on both OS9 and
650 OSX.
651
652- The core is now linked with CoreServices not Carbon; as a side
653 result, default 8bit encoding on OSX is now ASCII.
654
655- Python should now build on OSX 10.1.1
656
Tim Peters84362bc2001-10-19 17:55:30 +0000657
Tim Petersabf925f2001-09-28 21:53:42 +0000658What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000659Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000660===========================
661
662Type/class unification and new-style classes
663
Guido van Rossum687ae002001-10-15 22:03:32 +0000664- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000665 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000666 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000667 remains: the __dict__ of a new-style class is a read-only proxy; you
668 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000669 __defined__ attribute of new-style types no longer exists, for lack
670 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000671 future a __cache__ may be resurrected with a similar function, if I
672 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000673
Tim Peters1c9ca872001-10-04 06:43:12 +0000674- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
675 always returned None, even when there was a class docstring).
676
677- doctest now finds and runs docstrings attached to new-style classes,
678 class methods, static methods, and properties.
679
Guido van Rossum9074ef62001-10-16 21:34:49 +0000680Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000681
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000682- A very subtle syntactical pitfall in list comprehensions was fixed.
683 For example: [a+b for a in 'abc', for b in 'def']. The comma in
684 this example is a mistake. Previously, this would silently let 'a'
685 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
686 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
687 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
688 Note that [a for a in <singleton>] is a convoluted way to say
689 [<singleton>] anyway, so it's not like any expressiveness is lost.
690
Guido van Rossum9074ef62001-10-16 21:34:49 +0000691- getattr(obj, name, default) now only catches AttributeError, as
692 documented, rather than returning the default value for all
693 exceptions (which could mask bugs in a __getattr__ hook, for
694 example).
695
Fred Drakecb7a6b52001-10-22 18:41:51 +0000696- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000697 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000698 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000699 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000700
Guido van Rossum1c486092001-10-19 02:05:35 +0000701- unicode(obj) now behaves more like str(obj), accepting arbitrary
702 objects, and calling a __unicode__ method if it exists.
703 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000704 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000705
Barry Warsawf6fb1712001-10-19 05:35:40 +0000706- isinstance() now allows any object as the first argument and a
707 class, a type or something with a __bases__ tuple attribute for the
708 second argument. The second argument may also be a tuple of a
709 class, type, or something with __bases__, in which case isinstance()
710 will return true if the first argument is an instance of any of the
711 things contained in the second argument tuple. E.g.
712
713 isinstance(x, (A, B))
714
715 returns true if x is an instance of A or B.
716
Guido van Rossum9074ef62001-10-16 21:34:49 +0000717Extension modules
718
719- thread.start_new_thread() now returns the thread ID (previously None).
720
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000721- binascii has now two quopri support functions, a2b_qp and b2a_qp.
722
Guido van Rossumc524d952001-10-19 01:31:59 +0000723- readline now supports setting the startup_hook and the
724 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000725
Guido van Rossumc524d952001-10-19 01:31:59 +0000726- os and posix supports chroot(), setgroups() and unsetenv() where
727 available. The stat(), fstat(), statvfs() and fstatvfs() functions
728 now return "pseudo-sequences" -- the various fields can now be
729 accessed as attributes (e.g. os.stat("/").st_mtime) but for
730 backwards compatibility they also behave as a fixed-length sequence.
731 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000732 attributes.
733
734- time: localtime(), gmtime() and strptime() now return a
735 pseudo-sequence similar to the os.stat() return value, with
736 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000737
Guido van Rossum9074ef62001-10-16 21:34:49 +0000738- Decompression objects in the zlib module now accept an optional
739 second parameter to decompress() that specifies the maximum amount
740 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000741
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000742- optional SSL support in the socket module now exports OpenSSL
743 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
744 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000745 automatically seed its PRNG. Also, the keyfile and certfile
746 arguments to socket.ssl() are now optional.
747
748- posixmodule (and by extension, the os module on POSIX platforms) now
749 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000750
Guido van Rossum9074ef62001-10-16 21:34:49 +0000751Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000752
Tim Peters7402f792001-10-02 03:53:41 +0000753- doctest now excludes functions and classes not defined by the module
754 being tested, thanks to Tim Hochberg.
755
Fred Drakecb7a6b52001-10-22 18:41:51 +0000756- HotShot, a new profiler implemented using a C-based callback, has
757 been added. This substantially reduces the overhead of profiling,
758 but it is still quite preliminary. Support modules and
759 documentation will be added in upcoming releases (before 2.2 final).
760
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000761- profile now produces correct output in situations where an exception
762 raised in Python is cleared by C code (e.g. hasattr()). This used
763 to cause wrong output, including spurious claims of recursive
764 functions and attribution of time spent to the wrong function.
765
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000766 The code and documentation for the derived OldProfile and HotProfile
767 profiling classes was removed. The code hasn't worked for years (if
768 you tried to use them, they raised exceptions). OldProfile
769 intended to reproduce the behavior of the profiler Python used more
770 than 7 years ago, and isn't interesting anymore. HotProfile intended
771 to provide a faster profiler (but producing less information), and
772 that's a worthy goal we intend to meet via a different approach (but
773 without losing information).
774
Tim Peterscce092d2001-10-09 05:31:56 +0000775- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000776 a much better system-specific calibration constant. The constant can
777 now be specified in an instance constructor, or as a Profile class or
778 instance variable, instead of by editing profile.py's source code.
779 Calibration must still be done manually (see the docs for the profile
780 module).
781
782 Note that Profile.calibrate() must be overriden by subclasses.
783 Improving the accuracy required exploiting detailed knowledge of
784 profiler internals; the earlier method abstracted away the details
785 and measured a simplified model instead, but consequently computed
786 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000787
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000788- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000789 which indicates whether output is intended for the header 'Q'
790 encoding.
791
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000792- The SocketServer.ThreadingMixIn class now closes the request after
793 finish_request() returns. (Not when it errors out though.)
794
Barry Warsawf6fb1712001-10-19 05:35:40 +0000795- The nntplib module's NNTP.body() method has grown a `file' argument
796 to allow saving the message body to a file.
797
798- The email package has added a class email.Parser.HeaderParser which
799 only parses headers and does not recurse into the message's body.
800 Also, the module/class MIMEAudio has been added for representing
801 audio data (contributed by Anthony Baxter).
802
803- ftplib should be able to handle files > 2GB.
804
805- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
806 ON, and OFF.
807
Fred Drakecb7a6b52001-10-22 18:41:51 +0000808- xml.dom.minidom NodeList objects now support the length attribute
809 and item() method as required by the DOM specifications.
810
Guido van Rossumed554f62001-10-02 23:15:37 +0000811Tools/Demos
812
813- Demo/dns was removed. It no longer serves any purpose; a package
814 derived from it is now maintained by Anthony Baxter, see
815 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000816
Barry Warsawf6fb1712001-10-19 05:35:40 +0000817- The freeze tool has been made more robust, and two new options have
818 been added: -X and -E.
819
Tim Petersabf925f2001-09-28 21:53:42 +0000820Build
821
Barry Warsawf6fb1712001-10-19 05:35:40 +0000822- configure will use CXX in LINKCC if CXX is used to build main() and
823 the system requires to link a C++ main using the C++ compiler.
824
Tim Petersabf925f2001-09-28 21:53:42 +0000825C API
826
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000827- The documentation for the tp_compare slot is updated to require that
828 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
829 not correct. This is not yet enforced but will be enforced in
830 Python 2.3; even later, we may use -2 to indicate errors and +2 for
831 "NotImplemented". Right now, -1 should be used for an error return.
832
Tim Petersd38b1c72001-09-30 05:09:37 +0000833- PyLong_AsLongLong() now accepts int (as well as long) arguments.
834 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
835 as long) arguments.
836
Guido van Rossum3c288632001-10-16 21:13:49 +0000837- PyThread_start_new_thread() now returns a long int giving the thread
838 ID, if one can be calculated; it returns -1 for error, 0 if no
839 thread ID is calculated (this is an incompatible change, but only
840 the thread module used this API). This code has only really been
841 tested on Linux and Windows; other platforms please beware (and
842 report any bugs or strange behavior).
843
Guido van Rossum1c486092001-10-19 02:05:35 +0000844- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
845 input.
846
Tim Petersabf925f2001-09-28 21:53:42 +0000847New platforms
848
849Tests
850
851Windows
852
Tim Peters04cf1d32001-10-09 22:39:40 +0000853- Installer: If you install IDLE, and don't disable file-extension
854 registration, a new "Edit with IDLE" context (right-click) menu entry
855 is created for .py and .pyw files.
856
Tim Peters1ce3cf72001-10-01 17:58:40 +0000857- The signal module now supports SIGBREAK on Windows, thanks to Steven
858 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
859 action remains to call Win32 ExitProcess(). This can be changed via
860 signal.signal(). For example:
861
862 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
863 # (SIGINT) behavior.
864 import signal
865 signal.signal(signal.SIGBREAK,
866 signal.default_int_handler)
867
868 try:
869 while 1:
870 pass
871 except KeyboardInterrupt:
872 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
873 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
874 # program without the possibility for any Python-level cleanup).
875 print "Clean exit"
876
Tim Petersabf925f2001-09-28 21:53:42 +0000877
Tim Petersb07352e2001-09-08 01:25:47 +0000878What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000879Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000880===========================
881
Guido van Rossum808eea72001-09-25 04:15:41 +0000882Type/class unification and new-style classes
883
884- pydoc and inspect are now aware of new-style classes;
885 e.g. help(list) at the interactive prompt now shows proper
886 documentation for all operations on list objects.
887
888- Applications using Jim Fulton's ExtensionClass module can now safely
889 be used with Python 2.2. In particular, Zope 2.4.1 now works with
890 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
891 examples also work again. It is hoped that Gtk and Boost also work
892 with 2.2a4 and beyond. (If you can confirm this, please write
893 webmaster@python.org; if there are still problems, please open a bug
894 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000895
Tim Peters66c1a522001-09-24 21:17:50 +0000896- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
897 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
898 in the constructed property object. fget, fset and fdel weren't
899 discoverable from Python in 2.2a3. __doc__ is new, and allows to
900 associate a docstring with a property.
901
Guido van Rossum808eea72001-09-25 04:15:41 +0000902- Comparison overloading is now more completely implemented. For
903 example, a str subclass instance can properly be compared to a str
904 instance, and it can properly overload comparison. Ditto for most
905 other built-in object types.
906
907- The repr() of new-style classes has changed; instead of <type
908 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
909 *except* for built-in types, which are still rendered as <type
910 'Foo'> (to avoid upsetting existing code that might parse or
911 otherwise rely on repr() of certain type objects).
912
913- The repr() of new-style objects is now always <Foo object at XXX>;
914 previously, it was sometimes <Foo instance at XXX>.
915
916- For new-style classes, what was previously called __getattr__ is now
917 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000918 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000919 one in classic classes is defined which is called only if regular
920 attribute access raises AttributeError; to catch *all* attribute
921 access, you can use __getattribute__ (for new-style classes). If
922 both are defined, __getattribute__ is called first, and if it raises
923 AttributeError, __getattr__ is called.
924
925- The __class__ attribute of new-style objects can be assigned to.
926 The new class must have the same C-level object layout as the old
927 class.
928
929- The builtin file type can be subclassed now. In the usual pattern,
930 "file" is the name of the builtin type, and file() is a new builtin
931 constructor, with the same signature as the builtin open() function.
932 file() is now the preferred way to open a file.
933
934- Previously, __new__ would only see sequential arguments passed to
935 the type in a constructor call; __init__ would see both sequential
936 and keyword arguments. This made no sense whatsoever any more, so
937 now both __new__ and __init__ see all arguments.
938
939- Previously, hash() applied to an instance of a subclass of str or
940 unicode always returned 0. This has been repaired.
941
942- Previously, an operation on an instance of a subclass of an
943 immutable type (int, long, float, complex, tuple, str, unicode),
944 where the subtype didn't override the operation (and so the
945 operation was handled by the builtin type), could return that
946 instance instead a value of the base type. For example, if s was of
947 a str sublass type, s[:] returned s as-is. Now it returns a str
948 with the same value as s.
949
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000950- Provisional support for pickling new-style objects has been added.
951
Guido van Rossum808eea72001-09-25 04:15:41 +0000952Core
953
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000954- file.writelines() now accepts any iterable object producing strings.
955
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000956- PyUnicode_FromEncodedObject() now works very much like
957 PyObject_Str(obj) in that it tries to use __str__/tp_str
958 on the object if the object is not a string or buffer. This
959 makes unicode() behave like str() when applied to non-string/buffer
960 objects.
961
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000962- PyFile_WriteObject now passes Unicode objects to the file's write
963 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000964 of a print statement must support Unicode objects, i.e. they must
965 at least convert them into ASCII strings.
966
Guido van Rossum624c8af2001-09-18 15:21:04 +0000967- Thread scheduling on Solaris should be improved; it is no longer
968 necessary to insert a small sleep at the start of a thread in order
969 to let other runnable threads be scheduled.
970
Tim Petersb07352e2001-09-08 01:25:47 +0000971Library
972
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000973- StringIO.StringIO instances and cStringIO.StringIO instances support
974 read character buffer compatible objects for their .write() methods.
975 These objects are converted to strings and then handled as such
976 by the instances.
977
Barry Warsaw2f600732001-09-24 04:28:10 +0000978- The "email" package has been added. This is basically a port of the
979 mimelib package <http://sf.net/projects/mimelib> with API changes
980 and some implementations updated to use iterators and generators.
981
Tim Peters8a9c2842001-09-22 21:30:22 +0000982- difflib.ndiff() and difflib.Differ.compare() are generators now. This
983 restores the ability of Tools/scripts/ndiff.py to start producing output
984 before the entire comparison is complete.
985
Barry Warsaw58b072d2001-09-22 04:44:21 +0000986- StringIO.StringIO instances and cStringIO.StringIO instances support
987 iteration just like file objects (i.e. their .readline() method is
988 called for each iteration until it returns an empty string).
989
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000990- The codecs module has grown four new helper APIs to access
991 builtin codecs: getencoder(), getdecoder(), getreader(),
992 getwriter().
993
Guido van Rossum624c8af2001-09-18 15:21:04 +0000994- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
995 simplifies writing XML RPC servers.
996
Barry Warsaw647d5e82001-09-28 17:01:02 +0000997- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000998 after interpretation of symbolic links. On non-Unix systems, this
999 is an alias for os.path.abspath().
1000
Tim Peters16a77ad2001-09-08 04:00:12 +00001001- operator.indexOf() (PySequence_Index() in the C API) now works with any
1002 iterable object.
1003
Guido van Rossum624c8af2001-09-18 15:21:04 +00001004- smtplib now supports various authentication and security features of
1005 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001006
Guido van Rossum624c8af2001-09-18 15:21:04 +00001007- hmac: a new module implementing keyed hashing for message
1008 authentication.
1009
1010- mimetypes now recognizes more extensions and file types. At the
1011 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001012
Guido van Rossum624c8af2001-09-18 15:21:04 +00001013- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001014 Python 2.2 bytecode generation. It has also been promoted from a
1015 Tool to a standard library package. (Tools/compiler still exists as
1016 a sample driver.)
1017
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001018Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +00001019
Tim Petersb07352e2001-09-08 01:25:47 +00001020Build
1021
Guido van Rossum624c8af2001-09-18 15:21:04 +00001022- Large file support (LFS) is now automatic when the platform supports
1023 it; no more manual configuration tweaks are needed. On Linux, at
1024 least, it's possible to have a system whose C library supports large
1025 files but whose kernel doesn't; in this case, large file support is
1026 still enabled but doesn't do you any good unless you upgrade your
1027 kernel or share your Python executable with another system whose
1028 kernel has large file support.
1029
1030- The configure script now supplies plausible defaults in a
1031 cross-compilation environment. This doesn't mean that the supplied
1032 values are always correct, or that cross-compilation now works
1033 flawlessly -- but it's a first step (and it shuts up most of
1034 autoconf's warnings about AC_TRY_RUN).
1035
1036- The Unix build is now a bit less chatty, courtesy of the parser
1037 generator. The build is completely silent (except for errors) when
1038 using "make -s", thanks to a -q option to setup.py.
1039
Tim Petersb07352e2001-09-08 01:25:47 +00001040C API
1041
Guido van Rossum624c8af2001-09-18 15:21:04 +00001042- The "structmember" API now supports some new flag bits to deny read
1043 and/or write access to attributes in restricted execution mode.
1044
Tim Petersb07352e2001-09-08 01:25:47 +00001045New platforms
1046
Guido van Rossum624c8af2001-09-18 15:21:04 +00001047- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1048 (http://familiar.handhelds.org).
1049
Tim Petersb07352e2001-09-08 01:25:47 +00001050Tests
1051
Tim Peters8a9c2842001-09-22 21:30:22 +00001052- The "classic" standard tests, which work by comparing stdout to
1053 an expected-output file under Lib/test/output/, no longer stop at
1054 the first mismatch. Instead the test is run to completion, and a
1055 variant of ndiff-style comparison is used to report all differences.
1056 This is much easier to understand than the previous style of reporting.
1057
1058- The unittest-based standard tests now use regrtest's test_main()
1059 convention, instead of running as a side-effect of merely being
1060 imported. This allows these tests to be run in more natural and
1061 flexible ways as unittests, outside the regrtest framework.
1062
1063- regrtest.py is much better integrated with unittest and doctest now,
1064 especially in regard to reporting errors.
1065
Tim Petersb07352e2001-09-08 01:25:47 +00001066Windows
1067
Guido van Rossum624c8af2001-09-18 15:21:04 +00001068- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001069 that support it (NTFS under Windows 2000). See "What's New in
1070 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001071
Tim Petersb07352e2001-09-08 01:25:47 +00001072
Tim Petersedc99312001-08-22 21:36:50 +00001073What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001074Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001075===========================
1076
1077Core
1078
Tim Peters9fffa3e2001-09-04 05:14:19 +00001079- Conversion of long to float now raises OverflowError if the long is too
1080 big to represent as a C double.
1081
Tim Peters32f453e2001-09-03 08:35:41 +00001082- The 3-argument builtin pow() no longer allows a third non-None argument
1083 if either of the first two arguments is a float, or if both are of
1084 integer types and the second argument is negative (in which latter case
1085 the arguments are converted to float, so this is really the same
1086 restriction).
1087
Tim Peters5d2b77c2001-09-03 05:47:38 +00001088- The builtin dir() now returns more information, and sometimes much
1089 more, generally naming all attributes of an object, and all attributes
1090 reachable from the object via its class, and from its class's base
1091 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1092 an empty list. In 2.2a3,
1093
1094 >>> dir([])
1095 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1096 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1097 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1098 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1099 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1100 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1101 'reverse', 'sort']
1102
1103 dir(module) continues to return only the module's attributes, though.
1104
Tim Petersbdee63f2001-09-02 03:40:59 +00001105- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001106 than raising OverflowError. This is a partial implementation of PEP
1107 237. You can use -Wdefault::OverflowWarning to enable a warning for
1108 this situation, and -Werror::OverflowWarning to revert to the old
1109 OverflowError exception.
1110
Guido van Rossum61c345f2001-09-04 03:26:15 +00001111- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001112 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001113 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1114 -Qold, meaning the / operator has its classic meaning and no
1115 warnings are issued. Using -Qwarn issues a run-time warning about
1116 all uses of classic division for int and long arguments; -Qwarnall
1117 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001118 (for use with fixdiv.py).
1119 [Note: the remainder of this paragraph (preserved below) became
1120 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1121 <obsolete>
1122 Using -Qnew is questionable; it turns on new division by default, but
1123 only in the __main__ module. You can usefully combine -Qwarn or
1124 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1125 warns about classic division everywhere else.
1126 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001127
Tim Petersbdee63f2001-09-02 03:40:59 +00001128- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001129 long, float, str, unicode, and tuple. (The types complex, list and
1130 dictionary can also be subclassed; this was introduced earlier.)
1131 Note that restrictions apply when subclassing immutable built-in
1132 types: you can only affect the value of the instance by overloading
1133 __new__. You can add mutable attributes, and the subclass instances
1134 will have a __dict__ attribute, but you cannot change the "value"
1135 (as implemented by the base class) of an immutable subclass instance
1136 once it is created.
1137
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001138- The dictionary constructor now takes an optional argument, a
1139 mapping-like object, and initializes the dictionary from its
1140 (key, value) pairs.
1141
Tim Petersbdee63f2001-09-02 03:40:59 +00001142- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001143 "cooperative super calls" in a multiple inheritance setting. For an
1144 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1145
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001146- A new built-in type, property, has been added. This enables the
1147 creation of "properties". These are attributes implemented by
1148 getter and setter functions (or only one of these for read-only or
1149 write-only attributes), without the need to override __getattr__.
1150 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001151
Tim Petersbdee63f2001-09-02 03:40:59 +00001152- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001153 liberalized, to allow leading zeroes. Examples of literals now
1154 legal that were SyntaxErrors before:
1155
1156 00.0 0e3 0100j 07.5 00000000000000000008.
1157
Tim Petersbdee63f2001-09-02 03:40:59 +00001158- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001159 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1160
Tim Petersedc99312001-08-22 21:36:50 +00001161Library
1162
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001163- telnetlib includes symbolic names for the options, and support for
1164 setting an option negotiation callback.
1165
Tim Petersa40c7932001-09-05 22:36:56 +00001166- The new C standard no longer requires that math libraries set errno to
1167 ERANGE on overflow. For platform libraries that exploit this new
1168 freedom, Python's overflow-checking was wholly broken. A new overflow-
1169 checking scheme attempts to repair that, but may not be reliable on all
1170 platforms (C doesn't seem to provide anything both useful and portable
1171 in this area anymore).
1172
Martin v. Löwis44f86962001-09-05 13:44:54 +00001173- Asynchronous timeout actions are available through the new class
1174 threading.Timer.
1175
Tim Peters78526162001-09-05 00:53:45 +00001176- math.log and math.log10 now return sensible results for even huge
1177 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1178
Tim Petersbdee63f2001-09-02 03:40:59 +00001179- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001180 currently held. See the docs for the imp module.
1181
Tim Petersbdee63f2001-09-02 03:40:59 +00001182- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001183 dumps containing ints written on platforms where Python ints are 8 bytes.
1184 When read on a box where Python ints are 4 bytes, such values are
1185 converted to Python longs.
1186
Tim Petersbdee63f2001-09-02 03:40:59 +00001187- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001188 code objects is no longer allowed. This plugs a security hole.
1189
Steve Purcell6091cd62001-09-06 16:05:17 +00001190- unittest.TestResult instances no longer store references to tracebacks
1191 generated by test failures. This prevents unexpected dangling references
1192 to objects that should be garbage collected between tests.
1193
Tim Petersedc99312001-08-22 21:36:50 +00001194Tools
1195
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001196- Tools/scripts/fixdiv.py has been added which can be used to fix
1197 division operators as per PEP 238.
1198
Tim Petersedc99312001-08-22 21:36:50 +00001199Build
1200
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001201- If you are an adventurous person using Mac OS X you may want to look at
1202 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1203 application, which can be used for experimenting with Carbon or Cocoa.
1204 Discussion of this on pythonmac-sig, please.
1205
Tim Peters7eea37e2001-09-04 22:08:56 +00001206C API
1207
1208- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001209
Tim Peters9fffa3e2001-09-04 05:14:19 +00001210- Note that PyLong_AsDouble can fail! This has always been true, but no
1211 callers checked for it. It's more likely to fail now, because overflow
1212 errors are properly detected now. The proper way to check:
1213
1214 double x = PyLong_AsDouble(some_long_object);
1215 if (x == -1.0 && PyErr_Occurred()) {
1216 /* The conversion failed. */
1217 }
1218
Tim Petersbdee63f2001-09-02 03:40:59 +00001219- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001220 compile but will not participate in GC. To upgrade an extension
1221 module:
1222
1223 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001224
Neil Schemenauer4042c692001-08-30 15:38:01 +00001225 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1226 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001227
Neil Schemenauer4042c692001-08-30 15:38:01 +00001228 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1229 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001230
Neil Schemenauer4042c692001-08-30 15:38:01 +00001231 - remove PyGC_HEAD_SIZE from object size calculations
1232
1233 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1234
Tim Petersbdee63f2001-09-02 03:40:59 +00001235- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001236 These can be used safely to construct string objects from a
1237 sprintf-style format string (similar to the format string supported
1238 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001239
Tim Petersedc99312001-08-22 21:36:50 +00001240New platforms
1241
Tim Petersb7da0902001-09-02 23:01:43 +00001242- Stephen Hansen contributed patches sufficient to get a clean compile
1243 under Borland C (Windows), but he reports problems running it and ran
1244 out of time to complete the port. Volunteers? Expect a MemoryError
1245 when importing the types module; this is probably shallow, and
1246 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001247
Tim Petersedc99312001-08-22 21:36:50 +00001248Tests
1249
1250Windows
1251
Tim Peters6e13a562001-09-06 00:32:15 +00001252- Large file support is now enabled on Win32 platforms as well as on
1253 Win64. This means that, for example, you can use f.tell() and f.seek()
1254 to manipulate files larger than 2 gigabytes (provided you have enough
1255 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001256 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1257 filesize limit, and large file support makes no difference there.
1258 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1259 NTFS has no practical limit on file size, and files of any size can be
1260 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001261
Tim Petersbdee63f2001-09-02 03:40:59 +00001262- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001263 points to command.com (patch from Brian Quinlan).
1264
Tim Petersedc99312001-08-22 21:36:50 +00001265
Tim Peters20f51a72001-07-21 02:31:40 +00001266What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001267Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001268===========================
1269
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001270Build
1271
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001272- Tim Peters developed a brand new Windows installer using Wise 8.1,
1273 generously donated to us by Wise Solutions.
1274
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001275- configure supports a new option --enable-unicode, with the values
1276 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1277 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001278
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001279- A new configure option --enable-framework builds a Mac OS X framework,
1280 which "make frameworkinstall" will install. This provides a starting
1281 point for more mac-like functionality, join pythonmac-sig@python.org
1282 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001283
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001284- The NeXT platform is no longer supported.
1285
1286- The `new' module is now statically linked.
1287
Tim Peters0afb6092001-08-15 06:06:44 +00001288Tools
1289
1290- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001291 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001292 the module docstring for details.
1293
Tim Peters20f51a72001-07-21 02:31:40 +00001294Tests
1295
Tim Peters5e824c32001-08-12 22:25:01 +00001296- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001297 platforms, allowing to give clearer test result output. regrtest
1298 also has optional --use/-u switch to run normally disabled tests
1299 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001300
Tim Peters20f51a72001-07-21 02:31:40 +00001301- Several new tests in the standard test suite, with special thanks to
1302 Nick Mathewson.
1303
1304Core
1305
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001306- The floor division operator // has been added as outlined in PEP
1307 238. The / operator still provides classic division (and will until
1308 Python 3.0) unless "from __future__ import division" is included, in
1309 which case the / operator will provide true division. The operator
1310 module provides truediv() and floordiv() functions. Augmented
1311 assignment variants are included, as are the equivalent overloadable
1312 methods and C API methods. See the PEP for a full discussion:
1313 <http://python.sf.net/peps/pep-0238.html>
1314
Tim Peters6cd6a822001-08-17 22:11:27 +00001315- Future statements are now effective in simulated interactive shells
1316 (like IDLE). This should "just work" by magic, but read Michael
1317 Hudson's "Future statements in simulated shells" PEP 264 for full
1318 details: <http://python.sf.net/peps/pep-0264.html>.
1319
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001320- The type/class unification (PEP 252-253) was integrated into the
1321 trunk and is not so tentative any more (the exact specification of
1322 some features is still tentative). A lot of work has done on fixing
1323 bugs and adding robustness and features (performance still has to
1324 come a long way).
1325
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001326- Warnings about a mismatch in the Python API during extension import
1327 now use the Python warning framework (which makes it possible to
1328 write filters for these warnings).
1329
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001330- A function's __dict__ (aka func_dict) will now always be a
1331 dictionary. It used to be possible to delete it or set it to None,
1332 but now both actions raise TypeErrors. It is still legal to set it
1333 to a dictionary object. Getting func.__dict__ before any attributes
1334 have been assigned now returns an empty dictionary instead of None.
1335
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001336- A new command line option, -E, was added which disables the use of
1337 all environment variables, or at least those that are specifically
1338 significant to Python. Usually those have a name starting with
1339 "PYTHON". This was used to fix a problem where the tests fail if
1340 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1341 older distribution.
1342
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001343Library
1344
Tim Peters5e824c32001-08-12 22:25:01 +00001345- New class Differ and new functions ndiff() and restore() in difflib.py.
1346 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001347 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001348
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001349- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1350 value using the minimal quoting required for the value; more
1351 reliable than using xml.sax.saxutils.escape() for attribute values.
1352
1353- Readline completion support for cmd.Cmd was added.
1354
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001355- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1356
1357- Added function threading.BoundedSemaphore()
1358
1359- Added Ka-Ping Yee's cgitb.py module.
1360
1361- The `new' module now exposes the CO_xxx flags.
1362
Martin v. Löwis560da622001-11-24 09:24:51 +00001363- The gc module offers the get_referents function.
1364
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001365New platforms
1366
1367C API
1368
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001369- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1370 which provide a cross-platform implementations for the
1371 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1372 the standard sprintf() and vsprintf() C lib APIs, these versions
1373 apply bounds checking on the used buffer which enhances protection
1374 against buffer overruns.
1375
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001376- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001377 and extensions using different Unicode widths is rendered next to
1378 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001379 will result in an ImportError. Unicode extensions writers must make
1380 sure to check the Unicode width compatibility in their extensions by
1381 using at least one of the mangled Unicode APIs in the extension.
1382
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001383- Two new flags METH_NOARGS and METH_O are available in method definition
1384 tables to simplify implementation of methods with no arguments and a
1385 single untyped argument. Calling such methods is more efficient than
1386 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1387 deprecated.
1388
Tim Petersc1731372001-08-04 08:12:36 +00001389Windows
1390
1391- "import module" now compiles module.pyw if it exists and nothing else
1392 relevant is found.
1393
Tim Peters20f51a72001-07-21 02:31:40 +00001394
Guido van Rossum55a78992001-07-17 17:22:32 +00001395What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001396Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001397===========================
1398
1399Core
Tim Petersa814db52001-05-14 07:05:58 +00001400
Tim Peters6d6c1a32001-08-02 04:15:00 +00001401- TENTATIVELY, a large amount of code implementing much of what's
1402 described in PEP 252 (Making Types Look More Like Classes) and PEP
1403 253 (Subtyping Built-in Types) was added. This will be released
1404 with Python 2.2a1. Documentation will be provided separately
1405 through http://www.python.org/2.2/. The purpose of releasing this
1406 with Python 2.2a1 is to test backwards compatibility. It is
1407 possible, though not likely, that a decision is made not to release
1408 this code as part of 2.2 final, if any serious backwards
1409 incompapatibilities are found during alpha testing that cannot be
1410 repaired.
1411
Guido van Rossum55a78992001-07-17 17:22:32 +00001412- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001413 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001414 more 'yield' statements. See PEP 255. Since this adds a new
1415 keyword to the language, this feature must be enabled by including a
1416 future statement: "from __future__ import generators" (see PEP 236).
1417 Generators will become a standard feature in a future release
1418 (probably 2.3). Without this future statement, 'yield' remains an
1419 ordinary identifier, but a warning is issued each time it is used.
1420 (These warnings currently don't conform to the warnings framework of
1421 PEP 230; we intend to fix this in 2.2a2.)
1422
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001423- The UTF-16 codec was modified to be more RFC compliant. It will now
1424 only remove BOM characters at the start of the string and then
1425 only if running in native mode (UTF-16-LE and -BE won't remove a
1426 leading BMO character).
1427
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001428- Strings now have a new method .decode() to complement the already
1429 existing .encode() method. These two methods provide direct access
1430 to the corresponding decoders and encoders of the registered codecs.
1431
1432 To enhance the usability of the .encode() method, the special
1433 casing of Unicode object return values was dropped (Unicode objects
1434 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001435
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001436 Both methods will now return whatever the codec in charge of the
1437 requested encoding returns as object, e.g. Unicode codecs will
1438 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1439 will return u"äöü"). This enables codec writer to create codecs
1440 for various simple to use conversions.
1441
1442 New codecs were added to demonstrate these new features (the .encode()
1443 and .decode() columns indicate the type of the returned objects):
1444
1445 Name | .encode() | .decode() | Description
1446 ----------------------------------------------------------------------
1447 uu | string | string | UU codec (e.g. for email)
1448 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001449 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001450 zlib | string | string | zlib compression
1451 hex | string | string | 2-byte hex codec
1452 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1453
Mark Hammond2a0af792001-05-14 03:09:36 +00001454- Some operating systems now support the concept of a default Unicode
1455 encoding for file system operations. Notably, Windows supports 'mbcs'
1456 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001457 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001458 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001459
1460 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001461 functions that return filenames (such as os.listdir()) to return Python
1462 string objects pre-encoded using the default file system encoding for
1463 the platform. As this encoding is likely to be different from Python's
1464 default encoding, converting this name to a Unicode object before passing
1465 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001466 would attempt to use its default encoding (generally ASCII) rather than
1467 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001468
Tim Petersa814db52001-05-14 07:05:58 +00001469 In general, this change simply removes surprises when working with
1470 Unicode and the file system, making these operations work as you expect,
1471 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001472 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001473
Tim Peters61dff2b2001-05-08 15:43:37 +00001474- Float (and complex) literals in source code were evaluated to full
1475 precision only when running from a .py file; the same code loaded from a
1476 .pyc (or .pyo) file could suffer numeric differences starting at about the
1477 12th significant decimal digit. For example, on a machine with IEEE-754
1478 floating arithmetic,
1479
1480 x = 9007199254740992.0
1481 print long(x)
1482
1483 printed 9007199254740992 if run directly from .py, but 9007199254740000
1484 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1485 str(float) instead of repr(float) when building code objects. marshal
1486 now uses repr(float) instead, which should reproduce floats to full
1487 machine precision (assuming the platform C float<->string I/O conversion
1488 functions are of good quality).
1489
1490 This may cause floating-point results to change in some cases, and
1491 usually for the better, but may also cause numerically unstable
1492 algorithms to break.
1493
Tim Peters2f228e72001-05-13 00:19:31 +00001494- The implementation of dicts suffers fewer collisions, which has speed
1495 benefits. However, the order in which dict entries appear in dict.keys(),
1496 dict.values() and dict.items() may differ from previous releases for a
1497 given dict. Nothing is defined about this order, so no program should
1498 rely on it. Nevertheless, it's easy to write test cases that rely on the
1499 order by accident, typically because of printing the str() or repr() of a
1500 dict to an "expected results" file. See Lib/test/test_support.py's new
1501 sortdict(dict) function for a simple way to display a dict in sorted
1502 order.
1503
Tim Peters7a3bfc32001-06-12 01:22:22 +00001504- Many other small changes to dicts were made, resulting in faster
1505 operation along the most common code paths.
1506
Guido van Rossum10315822001-05-01 20:54:30 +00001507- Dictionary objects now support the "in" operator: "x in dict" means
1508 the same as dict.has_key(x).
1509
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001510- The update() method of dictionaries now accepts generic mapping
1511 objects. Specifically the argument object must support the .keys()
1512 and __getitem__() methods. This allows you to say, for example,
1513 {}.update(UserDict())
1514
Guido van Rossum10315822001-05-01 20:54:30 +00001515- Iterators were added; this is a generalized way of providing values
1516 to a for loop. See PEP 234. There's a new built-in function iter()
1517 to return an iterator. There's a new protocol to get the next value
1518 from an iterator using the next() method (in Python) or the
1519 tp_iternext slot (in C). There's a new protocol to get iterators
1520 using the __iter__() method (in Python) or the tp_iter slot (in C).
1521 Iterating (i.e. a for loop) over a dictionary generates its keys.
1522 Iterating over a file generates its lines.
1523
Tim Petersf553f892001-05-01 20:45:31 +00001524- The following functions were generalized to work nicely with iterator
1525 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001526 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001527 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1528 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001529 join() method of strings
1530 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001531 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1532 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001533 right-hand side of assignment statements with multiple targets, such as
1534 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001535
Tim Petersd85e1022001-05-11 21:51:48 +00001536- Accessing module attributes is significantly faster (for example,
1537 random.random or os.path or yourPythonModule.yourAttribute).
1538
Tim Peterse63415e2001-05-08 04:38:29 +00001539- Comparing dictionary objects via == and != is faster, and now works even
1540 if the keys and values don't support comparisons other than ==.
1541
Tim Peters95bf9392001-05-10 08:32:44 +00001542- Comparing dictionaries in ways other than == and != is slower: there were
1543 insecurities in the dict comparison implementation that could cause Python
1544 to crash if the element comparison routines for the dict keys and/or
1545 values mutated the dicts. Making the code bulletproof slowed it down.
1546
Tim Peterseb28ef22001-06-02 05:27:19 +00001547- Collisions in dicts are resolved via a new approach, which can help
1548 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001549 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001550 faster now. Thanks to Christian Tismer for pointing out the cause and
1551 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001552
Tim Peters52e155e2001-06-16 05:42:57 +00001553- repr() is much faster for large containers (dict, list, tuple).
1554
1555
Tim Petersa814db52001-05-14 07:05:58 +00001556Library
1557
Fred Drake960fdf92001-07-20 18:38:26 +00001558- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1559 were added to the string module. These a locale-indenpendent
1560 constants, unlike letters, lowercase, and uppercase. These are now
1561 use in appropriate locations in the standard library.
1562
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001563- The flags used in dlopen calls can now be configured using
1564 sys.setdlopenflags and queried using sys.getdlopenflags.
1565
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001566- Fredrik Lundh's xmlrpclib is now a standard library module. This
1567 provides full client-side XML-RPC support. In addition,
1568 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1569 one asyncore-based). Thanks to Eric Raymond for the documentation.
1570
Guido van Rossum643d3912001-07-05 14:46:25 +00001571- The xrange() object is simplified: it no longer supports slicing,
1572 repetition, comparisons, efficient 'in' checking, the tolist()
1573 method, or the start, stop and step attributes. See PEP 260.
1574
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001575- A new function fnmatch.filter to filter lists of file names was added.
1576
Barry Warsawffd674d2001-05-22 16:00:10 +00001577- calendar.py uses month and day names based on the current locale.
1578
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001579- strop is now *really* obsolete (this was announced before with 1.6),
1580 and issues DeprecationWarning when used (except for the four items
1581 that are still imported into string.py).
1582
Tim Petersa814db52001-05-14 07:05:58 +00001583- Cookie.py now sorts key+value pairs by key in output strings.
1584
1585- pprint.isrecursive(object) didn't correctly identify recursive objects.
1586 Now it does.
1587
Tim Peters95b3f782001-05-14 18:39:41 +00001588- pprint functions now much faster for large containers (tuple, list, dict).
1589
Tim Peters7b9542a2001-06-10 23:40:19 +00001590- New 'q' and 'Q' format codes in the struct module, corresponding to C
1591 types "long long" and "unsigned long long" (on Windows, __int64). In
1592 native mode, these can be used only when the platform C compiler supports
1593 these types (when HAVE_LONG_LONG is #define'd by the Python config
1594 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001595 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1596 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001597
Guido van Rossum83213cc2001-06-12 16:48:52 +00001598- The site module installs a new built-in function 'help' that invokes
1599 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1600 it displays a message reminding the user to use 'help()' or
1601 'help(object)'.
1602
Tim Petersa814db52001-05-14 07:05:58 +00001603Tests
1604
1605- New test_mutants.py runs dict comparisons where the key and value
1606 comparison operators mutute the dicts randomly during comparison. This
1607 rapidly causes Python to crash under earlier releases (not for the faint
1608 of heart: it can also cause Win9x to freeze or reboot!).
1609
1610- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001611 pprint.isreadable() return sensible results. Also verifies that simple
1612 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001613
Tim Peters4324aa32001-05-28 22:30:08 +00001614C API
1615
1616- Removed the unused last_is_sticky argument from the internal
1617 _PyTuple_Resize(). If this affects you, you were cheating.
1618
1619
Guido van Rossum55a78992001-07-17 17:22:32 +00001620======================================================================
1621
1622
Guido van Rossumffe13be2001-04-16 18:46:45 +00001623What's New in Python 2.1 (final)?
1624=================================
1625
1626We only changed a few things since the last release candidate, all in
1627Python library code:
1628
1629- A bug in the locale module was fixed that affected locales which
1630 define no grouping for numeric formatting.
1631
1632- A few bugs in the weakref module's implementations of weak
1633 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1634 and the test suite was updated to check for these bugs.
1635
1636- An old bug in the os.path.walk() function (introduced in Python
1637 2.0!) was fixed: a non-existent file would cause an exception
1638 instead of being ignored.
1639
1640- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1641 PyChecker.
1642
1643
Guido van Rossum5b08f132001-04-16 02:05:23 +00001644What's New in Python 2.1c2?
1645===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001646
Guido van Rossum5b08f132001-04-16 02:05:23 +00001647A flurry of small changes, and one showstopper fixed in the nick of
1648time made it necessary to release another release candidate. The list
1649here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001650
Guido van Rossum5b08f132001-04-16 02:05:23 +00001651Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001652
Guido van Rossum5b08f132001-04-16 02:05:23 +00001653- Tim discovered a nasty bug in the dictionary code, caused by
1654 PyDict_Next() calling dict_resize(), and the GC code's use of
1655 PyDict_Next() violating an assumption in dict_items(). This was
1656 fixed with considerable amounts of band-aid, but the net effect is a
1657 saner and more robust implementation.
1658
1659- Made a bunch of symbols static that were accidentally global.
1660
1661Build and Ports
1662
1663- The setup.py script didn't check for a new enough version of zlib
1664 (1.1.3 is needed). Now it does.
1665
1666- Changed "make clean" target to also remove shared libraries.
1667
1668- Added a more general warning about the SGI Irix optimizer to README.
1669
1670Library
1671
1672- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1673 omitted the slash between host and file.html.
1674
1675- The mailbox module's _Mailbox class contained a completely broken
1676 and undocumented seek() method. Ripped it out.
1677
1678- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1679 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1680
1681- Fixed a few last-minute bugs in unittest.
1682
1683Extensions
1684
1685- Reverted the patch to the OpenSSL code in socketmodule.c to support
1686 RAND_status() and the EGD, and the subsequent patch that tried to
1687 fix it for pre-0.9.5 versions; the problem with the patch is that on
1688 some systems it issues a warning whenever socket is imported, and
1689 that's unacceptable.
1690
1691Tests
1692
1693- Fixed the pickle tests to work with "import test.test_pickle".
1694
1695- Tweaked test_locale.py to actually run the test Windows.
1696
1697- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1698 not "wb" (which is not a valid mode at all).
1699
1700- Fix pstats browser crashes. Import readline if it exists to make
1701 the user interface nicer.
1702
1703- Add "import thread" to the top of test modules that import the
1704 threading module (test_asynchat and test_threadedtempfile). This
1705 prevents test failures caused by a broken threading module resulting
1706 from a previously caught failed import.
1707
1708- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1709 needed on some platforms (e.g. Solaris 8) when the tests are run
1710 twice in succession.
1711
1712- Skip rather than fail test_sunaudiodev if no audio device is found.
1713
1714
1715What's New in Python 2.1c1?
1716===========================
1717
1718This list was significantly updated when 2.1c2 was released; the 2.1c1
1719release didn't mention most changes that were actually part of 2.1c1:
1720
1721Legal
1722
1723- Copyright was assigned to the Python Software Foundation (PSF) and a
1724 PSF license (very similar to the CNRI license) was added.
1725
1726- The CNRI copyright notice was updated to include 2001.
1727
1728Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001729
Guido van Rossumc9932722001-04-12 02:31:27 +00001730- After a public outcry, assignment to __debug__ is no longer illegal;
1731 instead, a warning is issued. It will become illegal in 2.2.
1732
Guido van Rossum5b08f132001-04-16 02:05:23 +00001733- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1734 "%#x" now always prepends "0x", even if the value is zero.
1735
1736- Fixed some nits in the bytecode compiler.
1737
1738- Fixed core dumps when calling certain kinds of non-functions.
1739
1740- Fixed various core dumps caused by reference count bugs.
1741
1742Build and Ports
1743
1744- Use INSTALL_SCRIPT to install script files.
1745
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001746- New port: SCO Unixware 7, by Billy G. Allie.
1747
Guido van Rossum5b08f132001-04-16 02:05:23 +00001748- Updated RISCOS port.
1749
1750- Updated BeOS port and notes.
1751
1752- Various other porting problems resolved.
1753
1754Library
1755
1756- The TERMIOS and SOCKET modules are now truly obsolete and
1757 unnecessary. Their symbols are incorporated in the termios and
1758 socket modules.
1759
1760- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1761 better tests for pickling.
1762
1763- threading: make Condition.wait() robust against KeyboardInterrupt.
1764
1765- zipfile: add support to zipfile to support opening an archive
1766 represented by an open file rather than a file name. Fix bug where
1767 the archive was not properly closed. Fixed a bug in this bugfix
1768 where flush() was called for a read-only file.
1769
1770- imputil: added an uninstall() method to the ImportManager.
1771
1772- Canvas: fixed bugs in lower() and tkraise() methods.
1773
1774- SocketServer: API change (added overridable close_request() method)
1775 so that the TCP server can explicitly close the request.
1776
1777- pstats: Eric Raymond added a simple interactive statistics browser,
1778 invoked when the module is run as a script.
1779
1780- locale: fixed a problem in format().
1781
1782- webbrowser: made it work when the BROWSER environment variable has a
1783 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1784 KDE 2. Fixed some other nits.
1785
1786- unittest: changes to allow using a different exception than
1787 AssertionError, and added a few more function aliases. Some other
1788 small changes.
1789
1790- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1791
1792- asynchat: fixed a critical bug in asynchat that slipped through the
1793 2.1b2 release. Fixed another rare bug.
1794
1795- Fix some unqualified except: clauses (always a bad code example).
1796
1797XML
1798
1799- pyexpat: new API get_version_string().
1800
1801- Fixed some minidom bugs.
1802
1803Extensions
1804
1805- Fixed a core dump in _weakref. Removed the weakref.mapping()
1806 function (it adds nothing to the API).
1807
1808- Rationalized the use of header files in the readline module, to make
1809 it compile (albeit with some warnings) with the very recent readline
1810 4.2, without breaking for earlier versions.
1811
1812- Hopefully fixed a buffering problem in linuxaudiodev.
1813
1814- Attempted a fix to make the OpenSSL support in the socket module
1815 work again with pre-0.9.5 versions of OpenSSL.
1816
1817Tests
1818
1819- Added a test case for asynchat and asyncore.
1820
1821- Removed coupling between tests where one test failing could break
1822 another.
1823
1824Tools
1825
1826- Ping added an interactive help browser to pydoc, fixed some nits
1827 in the rest of the pydoc code, and added some features to his
1828 inspect module.
1829
1830- An updated python-mode.el version 4.1 which integrates Ken
1831 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1832 much nicer in XEmacs and Emacs. When stepping through your program
1833 with pdb, in either the shell window or the *Python* window, the
1834 source file and line will be tracked by an arrow. Very cool!
1835
1836- IDLE: syntax warnings in interactive mode are changed into errors.
1837
1838- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001839 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001840
1841- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001842
Barry Warsaw11e89c72001-04-11 20:37:57 +00001843
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001844What's New in Python 2.1 beta 2?
1845================================
1846
Guido van Rossum053ae352001-03-22 14:17:21 +00001847(Unlisted are many fixed bugs, more documentation, etc.)
1848
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001849Core language, builtins, and interpreter
1850
Guido van Rossum053ae352001-03-22 14:17:21 +00001851- The nested scopes work (enabled by "from __future__ import
1852 nested_scopes") is completed; in particular, the future now extends
1853 into code executed through exec, eval() and execfile(), and into the
1854 interactive interpreter.
1855
1856- When calling a base class method (e.g. BaseClass.__init__(self)),
1857 this is now allowed even if self is not strictly spoken a class
1858 instance (e.g. when using metaclasses or the Don Beaudry hook).
1859
1860- Slice objects are now comparable but not hashable; this prevents
1861 dict[:] from being accepted but meaningless.
1862
1863- Complex division is now calculated using less braindead algorithms.
1864 This doesn't change semantics except it's more likely to give useful
1865 results in extreme cases. Complex repr() now uses full precision
1866 like float repr().
1867
1868- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1869
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001870- It is illegal to assign to the name __debug__, which is set when the
1871 interpreter starts. It is effectively a compile-time constant.
1872
1873- A warning will be issued if a global statement for a variable
1874 follows a use or assignment of that variable.
1875
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001876Standard library
1877
Guido van Rossum053ae352001-03-22 14:17:21 +00001878- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1879 inspired by JUnit), is now part of the standard library. You now
1880 have a choice of two testing frameworks: unittest requires you to
1881 write testcases as separate code, doctest gathers them from
1882 docstrings. Both approaches have their advantages and
1883 disadvantages.
1884
1885- A new module Tix was added, which wraps the Tix extension library
1886 for Tk. With that module, it is not necessary to statically link
1887 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1888 require" command. See Demo/tix/.
1889
1890- tzparse.py is now obsolete.
1891
1892- In gzip.py, the seek() and tell() methods are removed -- they were
1893 non-functional anyway, and it's better if callers can test for their
1894 existence with hasattr().
1895
1896Python/C API
1897
1898- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1899 that's already in the dictionary during a PyDict_Next() iteration.
1900 This used to fail occasionally when a dictionary resize operation
1901 could be triggered that would rehash all the keys. All other
1902 modifications to the dictionary are still off-limits during a
1903 PyDict_Next() iteration!
1904
1905- New extended APIs related to passing compiler variables around.
1906
1907- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1908 implement isinstance() and issubclass().
1909
1910- Py_BuildValue() now has a "D" conversion to create a Python complex
1911 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001912
Fred Drake4e262a92001-03-22 18:26:47 +00001913- Extensions types which support weak references must now set the
1914 field allocated for the weak reference machinery to NULL themselves;
1915 this is done to avoid the cost of checking each object for having a
1916 weakly referencable type in PyObject_INIT(), since most types are
1917 not weakly referencable.
1918
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001919- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1920 free variables and cell variables to and from the frame's f_locals.
1921
1922- Variants of several functions defined in pythonrun.h have been added
1923 to support the nested_scopes future statement. The variants all end
1924 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1925 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1926 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001927 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001928
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001929Distutils
1930
1931- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1932 into the release tree.
1933
Tim Peters0e57abf2001-05-02 07:39:38 +00001934- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001935 (an uninstaller, more customization of the installer's display)
1936
1937- from Jack Jansen: added Mac-specific code to generate a dialog for
1938 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001939 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001940 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001941
1942- added 'platforms' and 'keywords' to the set of metadata that can be
1943 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001944
1945- applied patches from Jason Tishler to make the compiler class work with
1946 Cygwin.
1947
1948
Tim Peters2fe289a2001-03-01 22:19:38 +00001949What's New in Python 2.1 beta 1?
1950================================
Tim Petersd66595f2001-02-04 03:09:53 +00001951
1952Core language, builtins, and interpreter
1953
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001954- Following an outcry from the community about the amount of code
1955 broken by the nested scopes feature introduced in 2.1a2, we decided
1956 to make this feature optional, and to wait until Python 2.2 (or at
1957 least 6 months) to make it standard. The option can be enabled on a
1958 per-module basis by adding "from __future__ import nested_scopes" at
1959 the beginning of a module (before any other statements, but after
1960 comments and an optional docstring). See PEP 236 (Back to the
1961 __future__) for a description of the __future__ statement. PEP 227
1962 (Statically Nested Scopes) has been updated to reflect this change,
1963 and to clarify the semantics in a number of endcases.
1964
1965- The nested scopes code, when enabled, has been hardened, and most
1966 bugs and memory leaks in it have been fixed.
1967
1968- Compile-time warnings are now generated for a number of conditions
1969 that will break or change in meaning when nested scopes are enabled:
1970
1971 - Using "from...import *" or "exec" without in-clause in a function
1972 scope that also defines a lambda or nested function with one or
1973 more free (non-local) variables. The presence of the import* or
1974 bare exec makes it impossible for the compiler to determine the
1975 exact set of local variables in the outer scope, which makes it
1976 impossible to determine the bindings for free variables in the
1977 inner scope. To avoid the warning about import *, change it into
1978 an import of explicitly name object, or move the import* statement
1979 to the global scope; to avoid the warning about bare exec, use
1980 exec...in... (a good idea anyway -- there's a possibility that
1981 bare exec will be deprecated in the future).
1982
1983 - Use of a global variable in a nested scope with the same name as a
1984 local variable in a surrounding scope. This will change in
1985 meaning with nested scopes: the name in the inner scope will
1986 reference the variable in the outer scope rather than the global
1987 of the same name. To avoid the warning, either rename the outer
1988 variable, or use a global statement in the inner function.
1989
Neil Schemenauera35c6882001-02-27 04:45:05 +00001990- An optional object allocator has been included. This allocator is
1991 optimized for Python objects and should be faster and use less memory
1992 than the standard system allocator. It is not enabled by default
1993 because of possible thread safety problems. The allocator is only
1994 protected by the Python interpreter lock and it is possible that some
1995 extension modules require a thread safe allocator. The object
1996 allocator can be enabled by providing the "--with-pymalloc" option to
1997 configure.
1998
Tim Petersd66595f2001-02-04 03:09:53 +00001999Standard library
2000
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002001- pyexpat now detects the expat version if expat.h defines it. A
2002 number of additional handlers are provided, which are only available
2003 since expat 1.95. In addition, the methods SetParamEntityParsing and
2004 GetInputContext of Parser objects are available with 1.95.x
2005 only. Parser objects now provide the ordered_attributes and
2006 specified_attributes attributes. A new module expat.model was added,
2007 which offers a number of additional constants if 1.95.x is used.
2008
2009- xml.dom offers the new functions registerDOMImplementation and
2010 getDOMImplementation.
2011
2012- xml.dom.minidom offers a toprettyxml method. A number of DOM
2013 conformance issues have been resolved. In particular, Element now
2014 has an hasAttributes method, and the handling of namespaces was
2015 improved.
2016
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002017- Ka-Ping Yee contributed two new modules: inspect.py, a module for
2018 getting information about live Python code, and pydoc.py, a module
2019 for interactively converting docstrings to HTML or text.
2020 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002021 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002022 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2023 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002024
Tim Peters1eff7962001-03-01 02:31:33 +00002025- New library module difflib.py, primarily packaging the SequenceMatcher
2026 class at the heart of the popular ndiff.py file-comparison tool.
2027
2028- doctest.py (a framework for verifying Python code examples in docstrings)
2029 is now part of the std library.
2030
Tim Petersd66595f2001-02-04 03:09:53 +00002031Windows changes
2032
Guido van Rossume3955a82001-03-02 14:05:59 +00002033- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2034 small GUI that lets you browse the module docstrings using your
2035 default web browser.
2036
Tim Peters1eff7962001-03-01 02:31:33 +00002037- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2038 Platforms) is implemented. See
2039
2040 http://python.sourceforge.net/peps/pep-0235.html
2041
2042 for full details, especially the "Current Lower-Left Semantics" section.
2043 The new Windows import rules are simpler than before:
2044
2045 A. If the PYTHONCASEOK environment variable exists, same as
2046 before: silently accept the first case-insensitive match of any
2047 kind; raise ImportError if none found.
2048
2049 B. Else search sys.path for the first case-sensitive match; raise
2050 ImportError if none found.
2051
2052 The same rules have been implented on other platforms with case-
2053 insensitive but case-preserving filesystems too (including Cygwin, and
2054 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002055
Tim Peters25a9ce32001-02-19 07:06:36 +00002056- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2057 what it's supposed to do (and does do under NT and 2000) via direct
2058 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002059 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002060 all Win9x systems before.
2061
Tim Peters1eff7962001-03-01 02:31:33 +00002062- Build: Subproject _test (effectively) renamed to _testcapi.
2063
Tim Peters2fe289a2001-03-01 22:19:38 +00002064New platforms
2065
2066- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2067 Thanks to Steven Majewski!
2068
2069- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2070 Tishler!
2071
Guido van Rossum9089b272001-03-02 06:49:50 +00002072- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2073 Schwertberger! See RISCOS/README for more information -- it seems
2074 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002075 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002076
Tim Peters25a9ce32001-02-19 07:06:36 +00002077
Tim Petersd7b5e882001-01-25 03:36:26 +00002078What's New in Python 2.1 alpha 2?
2079=================================
Tim Peters40ead762001-01-27 05:35:26 +00002080
Tim Petersd7b5e882001-01-25 03:36:26 +00002081Core language, builtins, and interpreter
2082
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002083- Scopes nest. If a name is used in a function or class, but is not
2084 local, the definition in the nearest enclosing function scope will
2085 be used. One consequence of this change is that lambda statements
2086 could reference variables in the namespaces where the lambda is
2087 defined. In some unusual cases, this change will break code.
2088
2089 In all previous version of Python, names were resolved in exactly
2090 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002091 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002092 function A is defined within a function B, the names bound in B are
2093 not visible in A. The new rules make names bound in B visible in A,
2094 unless A contains a name binding that hides the binding in B.
2095
2096 Section 4.1 of the reference manual describes the new scoping rules
2097 in detail. The test script in Lib/test/test_scope.py demonstrates
2098 some of the effects of the change.
2099
2100 The new rules will cause existing code to break if it defines nested
2101 functions where an outer function has local variables with the same
2102 name as globals or builtins used by the inner function. Example:
2103
2104 def munge(str):
2105 def helper(x):
2106 return str(x)
2107 if type(str) != type(''):
2108 str = helper(str)
2109 return str.strip()
2110
2111 Under the old rules, the name str in helper() is bound to the
2112 builtin function str(). Under the new rules, it will be bound to
2113 the argument named str and an error will occur when helper() is
2114 called.
2115
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002116- The compiler will report a SyntaxError if "from ... import *" occurs
2117 in a function or class scope. The language reference has documented
2118 that this case is illegal, but the compiler never checked for it.
2119 The recent introduction of nested scope makes the meaning of this
2120 form of name binding ambiguous. In a future release, the compiler
2121 may allow this form when there is no possibility of ambiguity.
2122
Tim Peters40ead762001-01-27 05:35:26 +00002123- repr(string) is easier to read, now using hex escapes instead of octal,
2124 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2125
2126 >>> "\texample \r\n" + chr(0) + chr(255)
2127 '\texample \r\n\x00\xff' # in 2.1
2128 '\011example \015\012\000\377' # in 2.0
2129
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002130- Functions are now compared and hashed by identity, not by value, since
2131 the func_code attribute is writable.
2132
Fred Drakefb9d7122001-02-01 20:00:40 +00002133- Weak references (PEP 205) have been added. This involves a few
2134 changes in the core, an extension module (_weakref), and a Python
2135 module (weakref). The weakref module is the public interface. It
2136 includes support for "explicit" weak references, proxy objects, and
2137 mappings with weakly held values.
2138
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002139- A 'continue' statement can now appear in a try block within the body
2140 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002141 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002142
Tim Petersd7b5e882001-01-25 03:36:26 +00002143Standard library
2144
Barry Warsaw30dbd142001-01-31 22:14:01 +00002145- mailbox.py now has a new class, PortableUnixMailbox which is
2146 identical to UnixMailbox but uses a more portable scheme for
2147 determining From_ separators. Also, the constructors for all the
2148 classes in this module have a new optional `factory' argument, which
2149 is a callable used when new message classes must be instantiated by
2150 the next() method.
2151
Tim Petersd7b5e882001-01-25 03:36:26 +00002152- random.py is now self-contained, and offers all the functionality of
2153 the now-deprecated whrandom.py. See the docs for details. random.py
2154 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002155 and restoring the internal state of the generator; and jumpahead(n),
2156 for quickly forcing the internal state to be the same as if n calls to
2157 random() had been made. The latter is particularly useful for multi-
2158 threaded programs, creating one instance of the random.Random() class for
2159 each thread, then using .jumpahead() to force each instance to use a
2160 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002161
Tim Peters0de88fc2001-02-01 04:59:18 +00002162- random.py's seed() function is new. For bit-for-bit compatibility with
2163 prior releases, use the whseed function instead. The new seed function
2164 addresses two problems: (1) The old function couldn't produce more than
2165 about 2**24 distinct internal states; the new one about 2**45 (the best
2166 that can be done in the Wichmann-Hill generator). (2) The old function
2167 sometimes produced identical internal states when passed distinct
2168 integers, and there was no simple way to predict when that would happen;
2169 the new one guarantees to produce distinct internal states for all
2170 arguments in [0, 27814431486576L).
2171
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002172- The socket module now supports raw packets on Linux. The socket
2173 family is AF_PACKET.
2174
Tim Peters9ea17ac2001-02-02 05:57:15 +00002175- test_capi.py is a start at running tests of the Python C API. The tests
2176 are implemented by the new Modules/_testmodule.c.
2177
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002178- A new extension module, _symtable, provides provisional access to the
2179 internal symbol table used by the Python compiler. A higher-level
2180 interface will be added on top of _symtable in a future release.
2181
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002182- Removed the obsolete soundex module.
2183
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002184- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2185 the isSameNode method; NamedNodeMap the get method.
2186
2187- xml.sax.expatreader supports the lexical handler property; it
2188 generates comment, startCDATA, and endCDATA events.
2189
Tim Petersee826f82001-01-31 19:39:44 +00002190Windows changes
2191
2192- Build procedure: the zlib project is built in a different way that
2193 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002194 the zlib binary used. See PCbuild\readme.txt for details. Your old
2195 zlib-related directories can be deleted; you'll need to download fresh
2196 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002197
Tim Peters9ea17ac2001-02-02 05:57:15 +00002198- Build: New subproject _test for the benefit of test_capi.py (see above).
2199
Tim Petersb16c56f2001-02-02 21:24:51 +00002200- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2201 interface to some Python compiler internals).
2202
2203- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002204 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002205
Tim Petersa3a3a032000-11-30 05:22:44 +00002206What's New in Python 2.1 alpha 1?
2207=================================
2208
2209Core language, builtins, and interpreter
2210
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002211- There is a new Unicode companion to the PyObject_Str() API
2212 called PyObject_Unicode(). It behaves in the same way as the
2213 former, but assures that the returned value is an Unicode object
2214 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002215
Guido van Rossumf98eda02001-01-17 15:54:45 +00002216- The comparison operators support "rich comparison overloading" (PEP
2217 207). C extension types can provide a rich comparison function in
2218 the new tp_richcompare slot in the type object. The cmp() function
2219 and the C function PyObject_Compare() first try the new rich
2220 comparison operators before trying the old 3-way comparison. There
2221 is also a new C API PyObject_RichCompare() (which also falls back on
2222 the old 3-way comparison, but does not constrain the outcome of the
2223 rich comparison to a Boolean result).
2224
2225 The rich comparison function takes two objects (at least one of
2226 which is guaranteed to have the type that provided the function) and
2227 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2228 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2229 object, which may be NotImplemented (in which case the tp_compare
2230 slot function is used as a fallback, if defined).
2231
2232 Classes can overload individual comparison operators by defining one
2233 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002234 __ge__. There are no explicit "reflected argument" versions of
2235 these; instead, __lt__ and __gt__ are each other's reflection,
2236 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2237 reflection (similar at the C level). No other implications are
2238 made; in particular, Python does not assume that == is the Boolean
2239 inverse of !=, or that < is the Boolean inverse of >=. This makes
2240 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002241
2242 Classes or types that want to implement (in)equality tests but not
2243 the ordering operators (i.e. unordered types) should implement ==
2244 and !=, and raise an error for the ordering operators.
2245
Guido van Rossuma88479f2001-01-18 14:28:08 +00002246 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002247 Boolean; e.g. a matrix type might want to return a matrix of bits
2248 for A < B, giving elementwise comparisons. Such types should ensure
2249 that any interpretation of their value in a Boolean context raises
2250 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2251 at the C level) to always raise an exception.
2252
Guido van Rossuma88479f2001-01-18 14:28:08 +00002253- Complex numbers use rich comparisons to define == and != but raise
2254 an exception for <, <=, > and >=. Unfortunately, this also means
2255 that cmp() of two complex numbers raises an exception when the two
2256 numbers differ. Since it is not mathematically meaningful to compare
2257 complex numbers except for equality, I hope that this doesn't break
2258 too much code.
2259
Tim Peters3389f192001-02-18 08:48:49 +00002260- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002261 not defined by the language, other than that it's arbitrary but
2262 consistent (see the Reference Manual). An implementation detail changed
2263 in 2.1a1 such that None now compares less than any other object. Code
2264 relying on this new behavior (like code that relied on the previous
2265 behavior) does so at its own risk.
2266
Barry Warsaw573b5412001-01-15 20:43:18 +00002267- Functions and methods now support getting and setting arbitrarily
2268 named attributes (PEP 232). Functions have a new __dict__
2269 (a.k.a. func_dict) which hold the function attributes. Methods get
2270 and set attributes on their underlying im_func. It is a TypeError
2271 to set an attribute on a bound method.
2272
Guido van Rossum051e3352001-01-15 19:11:10 +00002273- The xrange() object implementation has been improved so that
2274 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2275 limitation that in this case len(xrange(sys.maxint)) can't be
2276 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2277 work fine as long as the index i doesn't actually reach 2**31.
2278 (Python uses regular ints for sequence and string indices; fixing
2279 that is much more work.)
2280
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002281- Two changes to from...import:
2282
Guido van Rossumba381232001-02-03 15:06:40 +00002283 1) "from M import X" now works even if (after loading module M)
2284 sys.modules['M'] is not a real module; it's basically a getattr()
2285 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002286
2287 2) "from M import *" now looks for M.__all__ to decide which names to
2288 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2289 filters out names starting with '_' as before. Whether or not
2290 __all__ exists, there's no restriction on the type of M.
2291
Guido van Rossumf61f1662001-01-10 20:13:55 +00002292- File objects have a new method, xreadlines(). This is the fastest
2293 way to iterate over all lines in a file:
2294
2295 for line in file.xreadlines():
2296 ...do something to line...
2297
2298 See the xreadlines module (mentioned below) for how to do this for
2299 other file-like objects.
2300
2301- Even if you don't use file.xreadlines(), you may expect a speedup on
2302 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002303 quite a bit in platform-specific ways: on systems (like Linux) that
2304 support flockfile(), getc_unlocked(), and funlockfile(), those are
2305 used by default. On systems (like Windows) without getc_unlocked(),
2306 a complicated (but still thread-safe) method using fgets() is used by
2307 default.
2308
Tim Petersd52269b2001-01-25 06:23:18 +00002309 You can force use of the fgets() method by #define'ing
2310 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002311 getc_unlocked()).
2312
Tim Petersd52269b2001-01-25 06:23:18 +00002313 You can force fgets() not to be used by #define'ing
2314 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002315 test_bufio.py fails -- and let us know if it does!).
2316
2317- In addition, the fileinput module, while still slower than the other
2318 methods on most platforms, has been sped up too, by using
2319 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002320
2321- Support for run-time warnings has been added, including a new
2322 command line option (-W) to specify the disposition of warnings.
2323 See the description of the warnings module below.
2324
2325- Extensive changes have been made to the coercion code. This mostly
2326 affects extension modules (which can now implement mixed-type
2327 numerical operators without having to use coercion), but
2328 occasionally, in boundary cases the coercion semantics have changed
2329 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002330 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002331 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002332 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002333
Guido van Rossumf98eda02001-01-17 15:54:45 +00002334- In connection with the coercion changes, a new built-in singleton
2335 object, NotImplemented is defined. This can be returned for
2336 operations that wish to indicate they are not implemented for a
2337 particular combination of arguments. From C, this is
2338 Py_NotImplemented.
2339
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002340- The interpreter accepts now bytecode files on the command line even
2341 if they do not have a .pyc or .pyo extension. On Linux, after executing
2342
Martin v. Löwise214baa2001-02-04 22:37:56 +00002343import imp,sys,string
2344magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2345reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2346open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002347
2348 any byte code file can be used as an executable (i.e. as an argument
2349 to execve(2)).
2350
Tim Peters9940b802000-12-01 07:59:35 +00002351- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002352 character. In 1.6 and earlier, they never produced a sign,
2353 and raised an error if the value of the long was too large
2354 to fit in a Python int. In 2.0, they produced a sign if and
2355 only if too large to fit in an int. This was inconsistent
2356 across platforms (because the size of an int varies across
2357 platforms), and inconsistent with hex() and oct(). Example:
2358
2359 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002360 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002361 'ffffffbe' # in 2.0 and before, on 32-bit machines
2362 >>> hex(-0x42L)
2363 '-0x42L' # in all versions of Python
2364
Tim Peters9940b802000-12-01 07:59:35 +00002365 The behavior of %d formats for negative Python longs remains
2366 the same as in 2.0 (although in 1.6 and before, they raised
2367 an error if the long didn't fit in a Python int).
2368
2369 %u formats don't make sense for Python longs, but are allowed
2370 and treated the same as %d in 2.1. In 2.0, a negative long
2371 formatted via %u produced a sign if and only if too large to
2372 fit in an int. In 1.6 and earlier, a negative long formatted
2373 via %u raised an error if it was too big to fit in an int.
2374
Guido van Rossum3661d392000-12-12 22:10:31 +00002375- Dictionary objects have an odd new method, popitem(). This removes
2376 an arbitrary item from the dictionary and returns it (in the form of
2377 a (key, value) pair). This can be useful for algorithms that use a
2378 dictionary as a bag of "to do" items and repeatedly need to pick one
2379 item. Such algorithms normally end up running in quadratic time;
2380 using popitem() they can usually be made to run in linear time.
2381
Tim Peters36cdad12000-12-29 02:06:45 +00002382Standard library
2383
Thomas Woutersfe385252001-01-19 23:16:56 +00002384- In the time module, the time argument to the functions strftime,
2385 localtime, gmtime, asctime and ctime is now optional, defaulting to
2386 the current time (in the local timezone).
2387
Guido van Rossumda91f222001-01-15 16:36:08 +00002388- The ftplib module now defaults to passive mode, which is deemed a
2389 more useful default given that clients are often inside firewalls
2390 these days. Note that this could break if ftplib is used to connect
2391 to a *server* that is inside a firewall, from outside; this is
2392 expected to be a very rare situation. To fix that, you can call
2393 ftp.set_pasv(0).
2394
Martin v. Löwis10a27872001-01-13 09:54:41 +00002395- The module site now treats .pth files not only for path configuration,
2396 but also supports extensions to the initialization code: Lines starting
2397 with import are executed.
2398
Guido van Rossumf61f1662001-01-10 20:13:55 +00002399- There's a new module, warnings, which implements a mechanism for
2400 issuing and filtering warnings. There are some new built-in
2401 exceptions that serve as warning categories, and a new command line
2402 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2403 turns warnings into errors). warnings.warn(message[, category])
2404 issues a warning message; this can also be called from C as
2405 PyErr_Warn(category, message).
2406
2407- A new module xreadlines was added. This exports a single factory
2408 function, xreadlines(). The intention is that this code is the
2409 absolutely fastest way to iterate over all lines in an open
2410 file(-like) object:
2411
2412 import xreadlines
2413 for line in xreadlines.xreadlines(file):
2414 ...do something to line...
2415
2416 This is equivalent to the previous the speed record holder using
2417 file.readlines(sizehint). Note that if file is a real file object
2418 (as opposed to a file-like object), this is equivalent:
2419
2420 for line in file.xreadlines():
2421 ...do something to line...
2422
Tim Peters36cdad12000-12-29 02:06:45 +00002423- The bisect module has new functions bisect_left, insort_left,
2424 bisect_right and insort_right. The old names bisect and insort
2425 are now aliases for bisect_right and insort_right. XXX_right
2426 and XXX_left methods differ in what happens when the new element
2427 compares equal to one or more elements already in the list: the
2428 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002429 right. Code that doesn't care where equal elements end up should
2430 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002431
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002432- The new curses.panel module wraps the panel library that forms part
2433 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2434
Guido van Rossumf61f1662001-01-10 20:13:55 +00002435- The SocketServer module now sets the allow_reuse_address flag by
2436 default in the TCPServer class.
2437
2438- A new function, sys._getframe(), returns the stack frame pointer of
2439 the caller. This is intended only as a building block for
2440 higher-level mechanisms such as string interpolation.
2441
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002442- The pyexpat module supports a number of new handlers, which are
2443 available only in expat 1.2. If invocation of a callback fails, it
2444 will report an additional frame in the traceback. Parser objects
2445 participate now in garbage collection. If expat reports an unknown
2446 encoding, pyexpat will try to use a Python codec; that works only
2447 for single-byte charsets. The parser type objects is exposed as
2448 XMLParserObject.
2449
2450- xml.dom now offers standard definitions for symbolic node type and
2451 exception code constants, and a hierarchy of DOM exceptions. minidom
2452 was adjusted to use them.
2453
2454- The conformance of xml.dom.minidom to the DOM specification was
2455 improved. It detects a number of additional error cases; the
2456 previous/next relationship works even when the tree is modified;
2457 Node supports the normalize() method; NamedNodeMap, DocumentType and
2458 DOMImplementation classes were added; Element supports the
2459 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2460 method.
2461
Guido van Rossumf61f1662001-01-10 20:13:55 +00002462Build issues
2463
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002464- For Unix (and Unix-compatible) builds, configuration and building of
2465 extension modules is now greatly automated. Rather than having to
2466 edit the Modules/Setup file to indicate which modules should be
2467 built and where their include files and libraries are, a
2468 distutils-based setup.py script now takes care of building most
2469 extension modules. All extension modules built this way are built
2470 as shared libraries. Only a few modules that must be linked
2471 statically are still listed in the Setup file; you won't need to
2472 edit their configuration.
2473
2474- Python should now build out of the box on Cygwin. If it doesn't,
2475 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002476
2477- Python now always uses its own (renamed) implementation of getopt()
2478 -- there's too much variation among C library getopt()
2479 implementations.
2480
2481- C++ compilers are better supported; the CXX macro is always set to a
2482 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002483
Tim Petersd92dfe02000-12-12 01:18:41 +00002484Windows changes
2485
2486- select module: By default under Windows, a select() call
2487 can specify no more than 64 sockets. Python now boosts
2488 this Microsoft default to 512. If you need even more than
2489 that, see the MS docs (you'll need to #define FD_SETSIZE
2490 and recompile Python from source).
2491
Guido van Rossumf61f1662001-01-10 20:13:55 +00002492- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2493 subdirectory is no more!
2494
Tim Petersa3a3a032000-11-30 05:22:44 +00002495
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002496What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002497=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002498
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002499Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002500changes are in the file HISTORY. If you are making the jump directly
2501from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2502HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002503
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002504Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2505the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2506http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002507
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002508--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002509
2510======================================================================
2511
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002512What's new in 2.0 (since release candidate 1)?
2513==============================================
2514
2515Standard library
2516
2517- The copy_reg module was modified to clarify its intended use: to
2518 register pickle support for extension types, not for classes.
2519 pickle() will raise a TypeError if it is passed a class.
2520
2521- Fixed a bug in gettext's "normalize and expand" code that prevented
2522 it from finding an existing .mo file.
2523
2524- Restored support for HTTP/0.9 servers in httplib.
2525
Tim Peters989b7b92000-10-16 20:24:53 +00002526- The math module was changed to stop raising OverflowError in case of
2527 underflow, and return 0 instead in underflow cases. Whether Python
2528 used to raise OverflowError in case of underflow was platform-
2529 dependent (it did when the platform math library set errno to ERANGE
2530 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002531
2532- Fixed a bug in StringIO that occurred when the file position was not
2533 at the end of the file and write() was called with enough data to
2534 extend past the end of the file.
2535
2536- Fixed a bug that caused Tkinter error messages to get lost on
2537 Windows. The bug was fixed by replacing direct use of
2538 interp->result with Tcl_GetStringResult(interp).
2539
2540- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2541 redirect response.
2542
2543- Several changes were made to distutils: Some debugging code was
2544 removed from util. Fixed the installer used when an external zip
2545 program (like WinZip) is not found; the source code for this
2546 installer is in Misc/distutils. check_lib() was modified to behave
2547 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2548 test for whether installed modules are on sys.path was changed to
2549 use both normcase() and normpath().
2550
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002551- Several minor bugs were fixed in the xml package (the minidom,
2552 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002553
2554- The regression test driver (regrtest.py) behavior when invoked with
2555 -l changed: It now reports a count of objects that are recognized as
2556 garbage but not freed by the garbage collector.
2557
Tim Peters989b7b92000-10-16 20:24:53 +00002558- The regression test for the math module was changed to test
2559 exceptional behavior when the test is run in verbose mode. Python
2560 cannot yet guarantee consistent exception behavior across platforms,
2561 so the exception part of test_math is run only in verbose mode, and
2562 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002563
2564Internals
2565
2566- PyOS_CheckStack() has been disabled on Win64, where it caused
2567 test_sre to fail.
2568
2569Build issues
2570
2571- Changed compiler flags, so that gcc is always invoked with -Wall and
2572 -Wstrict-prototypes. Users compiling Python with GCC should see
2573 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002574 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002575 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002576
Tim Petersa3a3a032000-11-30 05:22:44 +00002577- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002578
2579Tools and other miscellany
2580
2581- The compiler in Tools/compiler was updated to support the new
2582 language features introduced in 2.0: extended print statement, list
2583 comprehensions, and augmented assignments. The new compiler should
2584 also be backwards compatible with Python 1.5.2; the compiler will
2585 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002586 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002587
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002588What's new in 2.0 release candidate 1 (since beta 2)?
2589=====================================================
2590
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002591What is release candidate 1?
2592
2593We believe that release candidate 1 will fix all known bugs that we
2594intend to fix for the 2.0 final release. This release should be a bit
2595more stable than the previous betas. We would like to see even more
2596widespread testing before the final release, so we are producing this
2597release candidate. The final release will be exactly the same unless
2598any show-stopping (or brown bag) bugs are found by testers of the
2599release candidate.
2600
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002601All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002602to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002603
2604Core language, builtins, and interpreter
2605
2606- A bug that caused crashes when __coerce__ was used with augmented
2607 assignment, e.g. +=, was fixed.
2608
2609- Raise ZeroDivisionError when raising zero to a negative number,
2610 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2611 power operator and the result of math.pow(0.0, -2.0) will vary by
2612 platform. On Linux, it raises a ValueError.
2613
2614- A bug in Unicode string interpolation was fixed that occasionally
2615 caused errors with formats including "%%". For example, the
2616 following expression "%% %s" % u"abc" no longer raises a TypeError.
2617
2618- Compilation of deeply nested expressions raises MemoryError instead
2619 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2620
2621- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2622 rendering them useless. They are now written in binary mode again.
2623
2624Standard library
2625
2626- Keyword arguments are now accepted for most pattern and match object
2627 methods in SRE, the standard regular expression engine.
2628
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002629- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002630 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002631
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002632- Several bugs in the Unicode handling and error handling in _tkinter
2633 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002634
2635- Fix memory management errors in Merge() and Tkapp_Call() routines.
2636
2637- Several changes were made to cStringIO to make it compatible with
2638 the file-like object interface and with StringIO. If operations are
2639 performed on a closed object, an exception is raised. The truncate
2640 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002641 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002642
2643- There were many changes made to the linuxaudiodev module and its
2644 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002645 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002646
2647 Note that this module is named poorly, because it should work
2648 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002649 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002650
2651 The module now raises exceptions when errors occur instead of
2652 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2653 audio) and defines a getptr() method that calls the
2654 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2655
2656- The library_version attribute, introduced in an earlier beta, was
2657 removed because it can not be supported with early versions of the C
2658 readline library, which provides no way to determine the version at
2659 compile-time.
2660
2661- The binascii module is now enabled on Win64.
2662
Tim Peters46446d62000-10-09 21:19:31 +00002663- tokenize.py no longer suffers "recursion depth" errors when parsing
2664 programs with very long string literals.
2665
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002666Internals
2667
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002668- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002669 which is called when the interpreter starts up to determine where
2670 the standard library is installed. These vulnerabilities affect all
2671 previous versions of Python and can be exploited by setting very
2672 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2673 setuid Python script, although use of the wrapper in
2674 Misc/setuid-prog.c will eliminate the vulnerability.
2675
2676- Fixed garbage collection bugs in instance creation that were
2677 triggered when errors occurred during initialization. The solution,
2678 applied in cPickle and in PyInstance_New(), is to call
2679 PyObject_GC_Init() after the initialization of the object's
2680 container attributes is complete.
2681
2682- pyexpat adds definitions of PyModule_AddStringConstant and
2683 PyModule_AddObject if the Python version is less than 2.0, which
2684 provides compatibility with PyXML on Python 1.5.2.
2685
2686- If the platform has a bogus definition for LONG_BIT (the number of
2687 bits in a long), an error will be reported at compile time.
2688
2689- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2690 collection crashes and possibly other, unreported crashes.
2691
2692- Fixed a memory leak in _PyUnicode_Fini().
2693
2694Build issues
2695
2696- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002697 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002698 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002699
2700- The mmap.PAGESIZE constant is now initialized using sysconf when
2701 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2702
2703- The md5 file should now compile on all platforms.
2704
2705- The select module now compiles on platforms that do not define
2706 POLLRDNORM and related constants.
2707
2708- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002709 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002710
Jeremy Hylton10921202000-10-09 18:34:12 +00002711- BeOS: A number of changes were made to the build and installation
2712 process. ar-fake now operates on a directory of object files.
2713 dl_export.h is gone, and its macros now appear on the mwcc command
2714 line during build on PPC BeOS.
2715
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002716- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002717 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002718
2719- Cygwin: Support for shared libraries, Tkinter, and sockets.
2720
2721- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2722
2723Tools and other miscellany
2724
2725- Removed debugging prints from main used with freeze.
2726
Tim Peters46446d62000-10-09 21:19:31 +00002727- IDLE auto-indent no longer crashes when it encounters Unicode
2728 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002729
2730What's new in 2.0 beta 2 (since beta 1)?
2731========================================
2732
2733Core language, builtins, and interpreter
2734
Tim Peters482c0212000-09-26 06:33:09 +00002735- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002736 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002737
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002738- Add -h and -V command line options to print the usage message and
2739 Python version number and exit immediately.
2740
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002741- eval() and exec accept Unicode objects as code parameters.
2742
2743- getattr() and setattr() now also accept Unicode objects for the
2744 attribute name, which are converted to strings using the default
2745 encoding before lookup.
2746
2747- Multiplication on string and Unicode now does proper bounds
2748 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2749 string is too long."
2750
2751- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002752 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002753
Jeremy Hylton1b618592000-09-26 05:32:36 +00002754
2755Standard library and extensions
2756
Guido van Rossum5b08f132001-04-16 02:05:23 +00002757- socket module: the OpenSSL code now adds support for RAND_status()
2758 and EGD (Entropy Gathering Device).
2759
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002760- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002761 argument checking; it still takes no arguments.
2762
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002763- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002764
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002765- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002766
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002767- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002768
2769- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002770 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002771
2772- copy: Copy Unicode objects atomically.
2773
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002774- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002775
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002776- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002777
Fred Drake67233bc2000-09-26 16:40:27 +00002778- dbm: Add get() and setdefault() methods to dbm object. Add constant
2779 `library' to module that names the library used. Added doc strings
2780 and method names to error messages. Uses configure to determine
2781 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2782 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002783
2784- distutils: Update to version 0.9.3.
2785
2786- dl: Add several dl.RTLD_ constants.
2787
2788- fpectl: Now supported on FreeBSD.
2789
2790- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2791 found by the collector will be saved in gc.garbage. This is useful
2792 for debugging a program that creates reference cycles.
2793
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002794- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002795 of HTTP class. Do not close socket on zero-length response. Do not
2796 crash when server sends invalid content-length header.
2797
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002798- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002799
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002800- marshal: When reading a short, sign-extend on platforms where shorts
2801 are bigger than 16 bits. When reading a long, repair the unportable
2802 sign extension that was being done for 64-bit machines. (It assumed
2803 that signed right shift sign-extends.)
2804
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002805- operator: Add contains(), invert(), __invert__() as aliases for
2806 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002807
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002808- os: Add support for popen2() and popen3() on all platforms where
2809 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002810
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002811- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002812 clicking on a file in Explorer (or passing the file name to the
2813 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002814
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002815- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002816 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002817
2818- pickle: Now raises ValueError when an invalid pickle that contains
2819 a non-string repr where a string repr was expected. This behavior
2820 matches cPickle.
2821
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002822- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002823
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002824- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002825
2826- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002827 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002828 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002829
2830- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002831 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002832
2833- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002834 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002835 few cycles during startup since the first call to
2836 setdefaultencoding() will initialize the codec registry and the
2837 encodings package.
2838
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002839- socket: Support for size hint in readlines() method of object returned
2840 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002841
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002842- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002843 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002844 is followed by whitespace.
2845
Tim Petersa3a3a032000-11-30 05:22:44 +00002846- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002847
2848- struct: Check ranges for bytes and shorts.
2849
2850- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002851 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002852
2853- Tkinter: Image objects are now guaranteed to have unique ids. Set
2854 event.delta to zero if Tk version doesn't support mousewheel.
2855 Removed some debugging prints.
2856
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002857- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002858
Fred Drake67233bc2000-09-26 16:40:27 +00002859- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002860 which works around a bug in Norton AntiVirus 2000 that leads directly
2861 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002862
2863- xml: New version detection code allows PyXML to override standard
2864 XML package if PyXML version is greater than 0.6.1.
2865
Fred Drake64bb3802000-09-26 16:21:35 +00002866- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2867 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2868 tree only for nodes which are sufficiently interesting to a specific
2869 application. Does not provide the HTML-specific extensions. Still
2870 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002871
Fred Drake64bb3802000-09-26 16:21:35 +00002872- xml.sax: SAX 2 support for Python, including all the handler
2873 interfaces needed to process XML 1.0 compliant XML. Some
2874 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002875
Fred Drake64bb3802000-09-26 16:21:35 +00002876- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2877 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002878
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002879
Jeremy Hylton1b618592000-09-26 05:32:36 +00002880C API
2881
2882- Add three new convenience functions for module initialization --
2883 PyModule_AddObject(), PyModule_AddIntConstant(), and
2884 PyModule_AddStringConstant().
2885
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002886- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002887 removed and add #error to Python.h if NULL isn't defined after
2888 #include of stdio.h.
2889
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002890- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002891 backwards compatibility (at the source level) with old extensions.
2892
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002893- A wrapper API was added for signal() and sigaction(). Instead of
2894 either function, always use PyOS_getsig() to get a signal handler
2895 and PyOS_setsig() to set one. A new convenience typedef
2896 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002897
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002898- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002899 internal data buffer and size of a string object -- or the default
2900 encoded version of a Unicode object.
2901
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002902- PyString_Size() and PyString_AsString() accept Unicode objects.
2903
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002904- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002905 exists). INT_MAX and LONG_MAX will always be defined, even if
2906 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002907
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002908- PyFloat_FromString takes a second argument, pend, that was
2909 effectively useless. It is now officially useless but preserved for
2910 backwards compatibility. If the pend argument is not NULL, *pend is
2911 set to NULL.
2912
2913- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2914 for the attribute name. See note on getattr() above.
2915
2916- A few bug fixes to argument processing for Unicode.
2917 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2918 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2919 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002920 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002921
2922- Py_BuildValue accepts B format (for bgen-generated code).
2923
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002924
Jeremy Hylton1b618592000-09-26 05:32:36 +00002925Internals
2926
2927- On Unix, fix code for finding Python installation directory so that
2928 it works when argv[0] is a relative path.
2929
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002930- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002931 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002932 rather than by generating a copy of the object.
2933
Tim Peters482c0212000-09-26 06:33:09 +00002934- Several of the internal Unicode tables are much smaller now, and
2935 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002936
Jeremy Hylton97693b02000-09-26 17:42:51 +00002937- In the garbage collector: Fixed bug in collection of tuples. Fixed
2938 bug that caused some instances to be removed from the container set
2939 while they were still live. Fixed parsing in gc.set_debug() for
2940 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002941
2942- Fixed refcount problem in instance deallocation that only occurred
2943 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2944
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002945- On Windows, getpythonregpath is now protected against null data in
2946 registry key.
2947
2948- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002949 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002950
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002951
Jeremy Hylton1b618592000-09-26 05:32:36 +00002952Build and platform-specific issues
2953
2954- Better support of GNU Pth via --with-pth configure option.
2955
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002956- Python/C API now properly exposed to dynamically-loaded extension
2957 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002958
2959- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2960 Don't define MS_SYNC to be zero when it is undefined. Added missing
2961 prototypes in posixmodule.c.
2962
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002963- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002964 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002965
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002966- Fix largefile support on older NetBSD systems and OpenBSD by adding
2967 define for TELL64.
2968
2969
2970Tools and other miscellany
2971
2972- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2973
2974- freeze: The modulefinder now works with 2.0 opcodes.
2975
Tim Petersa3a3a032000-11-30 05:22:44 +00002976- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002977 Move hackery of sys.argv until after the Tk instance has been
2978 created, which allows the application-specific Tkinter
2979 initialization to be executed if present; also pass an explicit
2980 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002981
Jeremy Hylton1b618592000-09-26 05:32:36 +00002982
2983What's new in 2.0 beta 1?
2984=========================
2985
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002986Source Incompatibilities
2987------------------------
2988
2989None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2990such as single-argument append(), connect() and bind(), and changes to
2991str(long) and repr(float).
2992
2993
2994Binary Incompatibilities
2995------------------------
2996
2997- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2998with Python 2.0; these extensions will have to be rebuilt for Python
29992.0.
3000
3001- On Windows, attempting to import a third party extension built for
3002Python 1.5.x or 1.6 results in an immediate crash; there's not much we
3003can do about this. Check your PYTHONPATH environment variable!
3004
3005- Python bytecode files (*.pyc and *.pyo) are not compatible between
3006releases.
3007
3008
3009Overview of Changes Since 1.6
3010-----------------------------
3011
3012There are many new modules (including brand new XML support through
3013the xml package, and i18n support through the gettext module); a list
3014of all new modules is included below. Lots of bugs have been fixed.
3015
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003016The process for making major new changes to the language has changed
3017since Python 1.6. Enhancements must now be documented by a Python
3018Enhancement Proposal (PEP) before they can be accepted.
3019
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003020There are several important syntax enhancements, described in more
3021detail below:
3022
3023 - Augmented assignment, e.g. x += 1
3024
3025 - List comprehensions, e.g. [x**2 for x in range(10)]
3026
3027 - Extended import statement, e.g. import Module as Name
3028
3029 - Extended print statement, e.g. print >> file, "Hello"
3030
3031Other important changes:
3032
3033 - Optional collection of cyclical garbage
3034
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003035Python Enhancement Proposal (PEP)
3036---------------------------------
3037
3038PEP stands for Python Enhancement Proposal. A PEP is a design
3039document providing information to the Python community, or describing
3040a new feature for Python. The PEP should provide a concise technical
3041specification of the feature and a rationale for the feature.
3042
3043We intend PEPs to be the primary mechanisms for proposing new
3044features, for collecting community input on an issue, and for
3045documenting the design decisions that have gone into Python. The PEP
3046author is responsible for building consensus within the community and
3047documenting dissenting opinions.
3048
3049The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003050
3051Augmented Assignment
3052--------------------
3053
3054This must have been the most-requested feature of the past years!
3055Eleven new assignment operators were added:
3056
Guido van Rossume905e952000-09-05 12:42:46 +00003057 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003058
3059For example,
3060
3061 A += B
3062
3063is similar to
3064
3065 A = A + B
3066
3067except that A is evaluated only once (relevant when A is something
3068like dict[index].attr).
3069
3070However, if A is a mutable object, A may be modified in place. Thus,
3071if A is a number or a string, A += B has the same effect as A = A+B
3072(except A is only evaluated once); but if a is a list, A += B has the
3073same effect as A.extend(B)!
3074
3075Classes and built-in object types can override the new operators in
3076order to implement the in-place behavior; the not-in-place behavior is
3077used automatically as a fallback when an object doesn't implement the
3078in-place behavior. For classes, the method name is derived from the
3079method name for the corresponding not-in-place operator by inserting
3080an 'i' in front of the name, e.g. __iadd__ implements in-place
3081__add__.
3082
3083Augmented assignment was implemented by Thomas Wouters.
3084
3085
3086List Comprehensions
3087-------------------
3088
3089This is a flexible new notation for lists whose elements are computed
3090from another list (or lists). The simplest form is:
3091
3092 [<expression> for <variable> in <sequence>]
3093
Guido van Rossum56db0952000-09-06 23:34:25 +00003094For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003095This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003096
3097You can also add a condition:
3098
3099 [<expression> for <variable> in <sequence> if <condition>]
3100
3101For example, [w for w in words if w == w.lower()] would yield the list
3102of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003103than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003104
3105You can also have nested for loops and more than one 'if' clause. For
3106example, here's a function that flattens a sequence of sequences::
3107
3108 def flatten(seq):
3109 return [x for subseq in seq for x in subseq]
3110
3111 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3112
3113This prints
3114
3115 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3116
3117List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003118Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003119
3120
3121Extended Import Statement
3122-------------------------
3123
3124Many people have asked for a way to import a module under a different
3125name. This can be accomplished like this:
3126
3127 import foo
3128 bar = foo
3129 del foo
3130
3131but this common idiom gets old quickly. A simple extension of the
3132import statement now allows this to be written as follows:
3133
3134 import foo as bar
3135
3136There's also a variant for 'from ... import':
3137
3138 from foo import bar as spam
3139
3140This also works with packages; e.g. you can write this:
3141
3142 import test.regrtest as regrtest
3143
3144Note that 'as' is not a new keyword -- it is recognized only in this
3145context (this is only possible because the syntax for the import
3146statement doesn't involve expressions).
3147
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003148Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003149
3150
3151Extended Print Statement
3152------------------------
3153
3154Easily the most controversial new feature, this extension to the print
3155statement adds an option to make the output go to a different file
3156than the default sys.stdout.
3157
3158For example, to write an error message to sys.stderr, you can now
3159write:
3160
3161 print >> sys.stderr, "Error: bad dog!"
3162
3163As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003164evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003165
3166 print >> None, "Hello world"
3167
3168is equivalent to
3169
3170 print "Hello world"
3171
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003172Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003173
3174
3175Optional Collection of Cyclical Garbage
3176---------------------------------------
3177
3178Python is now equipped with a garbage collector that can hunt down
3179cyclical references between Python objects. It's no replacement for
3180reference counting; in fact, it depends on the reference counts being
3181correct, and decides that a set of objects belong to a cycle if all
3182their reference counts can be accounted for from their references to
3183each other. This devious scheme was first proposed by Eric Tiedemann,
3184and brought to implementation by Neil Schemenauer.
3185
3186There's a module "gc" that lets you control some parameters of the
3187garbage collection. There's also an option to the configure script
3188that lets you enable or disable the garbage collection. In 2.0b1,
3189it's on by default, so that we (hopefully) can collect decent user
3190experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003191performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003192off by default in the final 2.0 release.
3193
3194
3195Smaller Changes
3196---------------
3197
3198A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3199map(None, seq1, seq2, ...) when the sequences have the same length;
3200i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3201the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003202zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003203
3204sys.version_info is a tuple (major, minor, micro, level, serial).
3205
3206Dictionaries have an odd new method, setdefault(key, default).
3207dict.setdefault(key, default) returns dict[key] if it exists; if not,
3208it sets dict[key] to default and returns that value. Thus:
3209
3210 dict.setdefault(key, []).append(item)
3211
3212does the same work as this common idiom:
3213
3214 if not dict.has_key(key):
3215 dict[key] = []
3216 dict[key].append(item)
3217
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003218There are two new variants of SyntaxError that are raised for
3219indentation-related errors: IndentationError and TabError.
3220
3221Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3222escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003223
3224The limits on the size of expressions and file in Python source code
3225have been raised from 2**16 to 2**32. Previous versions of Python
3226were limited because the maximum argument size the Python VM accepted
3227was 2**16. This limited the size of object constructor expressions,
3228e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3229limit was raised thanks to a patch by Charles Waldman that effectively
3230fixes the problem. It is now much more likely that you will be
3231limited by available memory than by an arbitrary limit in Python.
3232
3233The interpreter's maximum recursion depth can be modified by Python
3234programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3235limit is the maximum number of recursive calls that can be made by
3236Python code. The limit exists to prevent infinite recursion from
3237overflowing the C stack and causing a core dump. The default value is
32381000. The maximum safe value for a particular platform can be found
3239by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003240
3241New Modules and Packages
3242------------------------
3243
3244atexit - for registering functions to be called when Python exits.
3245
3246imputil - Greg Stein's alternative API for writing custom import
3247hooks.
3248
3249pyexpat - an interface to the Expat XML parser, contributed by Paul
3250Prescod.
3251
3252xml - a new package with XML support code organized (so far) in three
3253subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3254would fill a volume. There's a special feature whereby a
3255user-installed package named _xmlplus overrides the standard
3256xmlpackage; this is intended to give the XML SIG a hook to distribute
3257backwards-compatible updates to the standard xml package.
3258
3259webbrowser - a platform-independent API to launch a web browser.
3260
3261
Guido van Rossume905e952000-09-05 12:42:46 +00003262Changed Modules
3263---------------
3264
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003265array -- new methods for array objects: count, extend, index, pop, and
3266remove
3267
3268binascii -- new functions b2a_hex and a2b_hex that convert between
3269binary data and its hex representation
3270
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003271calendar -- Many new functions that support features including control
3272over which day of the week is the first day, returning strings instead
3273of printing them. Also new symbolic constants for days of week,
3274e.g. MONDAY, ..., SUNDAY.
3275
3276cgi -- FieldStorage objects have a getvalue method that works like a
3277dictionary's get method and returns the value attribute of the object.
3278
3279ConfigParser -- The parser object has new methods has_option,
3280remove_section, remove_option, set, and write. They allow the module
3281to be used for writing config files as well as reading them.
3282
3283ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003284optionally support the RFC 959 REST command.
3285
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003286gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003287
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003288httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3289the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003290
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003291locale -- implement getdefaultlocale for Win32 and Macintosh
3292
3293marshal -- no longer dumps core when marshaling deeply nested or
3294recursive data structures
3295
3296os -- new functions isatty, seteuid, setegid, setreuid, setregid
3297
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003298os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3299support under Unix.
3300
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003301os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003302
3303os.path -- fix semantics of os.path.commonprefix
3304
3305smtplib -- support for sending very long messages
3306
3307socket -- new function getfqdn()
3308
3309readline -- new functions to read, write and truncate history files.
3310The readline section of the library reference manual contains an
3311example.
3312
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003313select -- add interface to poll system call
3314
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003315shutil -- new copyfileobj function
3316
3317SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3318HTTP server.
3319
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003320Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003321
3322urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003323e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003324
3325whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003326
3327
3328Obsolete Modules
3329----------------
3330
3331None. However note that 1.6 made a whole slew of modules obsolete:
3332stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3333poly, zmod, strop, util, whatsound.
3334
3335
3336Changed, New, Obsolete Tools
3337----------------------------
3338
Tim Peters8b092332000-09-05 20:15:25 +00003339None.
Guido van Rossume905e952000-09-05 12:42:46 +00003340
3341
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003342C-level Changes
3343---------------
3344
3345Several cleanup jobs were carried out throughout the source code.
3346
3347All C code was converted to ANSI C; we got rid of all uses of the
3348Py_PROTO() macro, which makes the header files a lot more readable.
3349
3350Most of the portability hacks were moved to a new header file,
3351pyport.h; several other new header files were added and some old
3352header files were removed, in an attempt to create a more rational set
3353of header files. (Few of these ever need to be included explicitly;
3354they are all included by Python.h.)
3355
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003356Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003357and Win64, especially for the new Intel Itanium processor. Mick also
3358added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003359
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003360The C APIs to return an object's size have been update to consistently
3361use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3362previous versions, the abstract interfaces used PyXXX_Length and the
3363concrete interfaces used PyXXX_Size. The old names,
3364e.g. PyObject_Length, are still available for backwards compatibility
3365at the API level, but are deprecated.
3366
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003367The PyOS_CheckStack function has been implemented on Windows by
3368Fredrik Lundh. It prevents Python from failing with a stack overflow
3369on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003370
3371The GC changes resulted in creation of two new slots on object,
3372tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003373the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003374
3375The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003376C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003377
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003378PyErr_Format has been updated to automatically calculate the size of
3379the buffer needed to hold the formatted result string. This change
3380prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003381
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003382New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003383
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003384PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3385that are the same as their non-Ex counterparts except they take an
3386extra flag argument that tells them to close the file when done.
3387
3388XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003389
Tim Peters8b092332000-09-05 20:15:25 +00003390
3391Windows Changes
3392---------------
3393
3394New popen2/popen3/peopen4 in os module (see Changed Modules above).
3395
3396os.popen is much more usable on Windows 95 and 98. See Microsoft
3397Knowledge Base article Q150956. The Win9x workaround described there
3398is implemented by the new w9xpopen.exe helper in the root of your
3399Python installation. Note that Python uses this internally; it is not
3400a standalone program.
3401
3402Administrator privileges are no longer required to install Python
3403on Windows NT or Windows 2000. If you have administrator privileges,
3404Python's registry info will be written under HKEY_LOCAL_MACHINE.
3405Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003406under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003407uses of Python, but will prevent some advanced uses from working
3408(for example, running a Python script as an NT service, or possibly
3409from CGI).
3410
3411[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3412installer; instead, it installs the needed Tcl/Tk files directly in the
3413Python directory. If you already have a Tcl/Tk installation, this
3414wastes some disk space (about 4 Megs) but avoids problems with
3415conflicting Tcl/Tk installations, and makes it much easier for Python
3416to ensure that Tcl/Tk can find all its files.
3417
3418[This was new in 1.6] The Windows installer now installs by default in
3419\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3420
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003421
3422Updates to the changes between 1.5.2 and 1.6
3423--------------------------------------------
3424
3425The 1.6 NEWS file can't be changed after the release is done, so here
3426is some late-breaking news:
3427
3428New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3429and changes to getlocale() and setlocale().
3430
3431The new module is now enabled per default.
3432
3433It is not true that the encodings codecs cannot be used for normal
3434strings: the string.encode() (which is also present on 8-bit strings
3435!) allows using them for 8-bit strings too, e.g. to convert files from
3436cp1252 (Windows) to latin-1 or vice-versa.
3437
3438Japanese codecs are available from Tamito KAJIYAMA:
3439http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3440
3441
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003442======================================================================