blob: 57eda69e4bbb873ea6897153db8c22f158005e7b [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 Rossumdeb09362002-08-09 17:16:30 +00009- The tempfile module has been overhauled for enhanced security. The
10 mktemp() function is now deprecated; new, safe replacements are
11 mkstemp() (for files) and mkdtemp() (for directories), and the
12 higher-level functions NamedTemporaryFile() and TemporaryFile().
13 Use of some global variables in this module is also deprecated; the
14 new functions have keyword arguments to provide the same
15 functionality. All Lib, Tools and Demo modules that used the unsafe
16 interfaces have been updated to use the safe replacements. Thanks
17 to Zack Weinberg!
18
Guido van Rossumd81a9832002-08-09 15:57:34 +000019- When x is an object whose class implements __mul__ and __rmul__,
20 1.0*x would correctly invoke __rmul__, but 1*x would erroneously
21 invoke __mul__. This was due to the sequence-repeat code in the int
22 type. This has been fixed now.
23
Barry Warsawd79f6832002-08-06 17:01:51 +000024- Previously, "str1 in str2" required str1 to be a string of length 1.
25 This restriction has been relaxed to allow str1 to be a string of
26 any length. Thus "'el' in 'hello world'" returns True now.
27
Guido van Rossumb57089c2002-08-06 16:20:26 +000028- File objects are now their own iterators. For a file f, iter(f) now
29 returns f (unless f is closed), and f.next() is similar to
30 f.readline() when EOF is not reached; however, f.next() uses a
31 readahead buffer that messes up the file position, so mixing
32 f.next() and f.readline() (or other methods) doesn't work right.
33 Calling f.seek() drops the readahead buffer, but other operations
34 don't. It so happens that this gives a nice additional speed boost
35 to "for line in file:"; the xreadlines method and corresponding
36 module are now obsolete.
37
Guido van Rossumde392d32002-08-05 14:17:20 +000038- Encoding declarations (PEP 263, phase 1) have been implemented. A
39 comment of the form "# -*- coding: <encodingname> -*-" in the first
40 or second line of a Python source file indicates the encoding.
Martin v. Löwis00f1e3f2002-08-04 17:29:52 +000041
Tim Petersf47630f2002-08-01 02:34:51 +000042- list.sort() has a new implementation. While cross-platform results
43 may vary, and in data-dependent ways, this is much faster on many
44 kinds of partially ordered lists than the previous implementation,
45 and reported to be just as fast on randomly ordered lists on
46 several major platforms. This sort is also stable (if A==B and A
47 precedes B in the list at the start, A precedes B after the sort too),
48 although the language definition does not guarantee stability. A
49 potential drawback is that list.sort() may require temp space of
50 len(list)*2 bytes (*4 on a 64-bit machine). It's therefore possible
51 for list.sort() to raise MemoryError now, even if a comparison function
52 does not. See <http://www.python.org/sf/587076> for full details.
53
Guido van Rossum2d5389c2002-07-23 03:44:35 +000054- All standard iterators now ensure that, once StopIteration has been
55 raised, all future calls to next() on the same iterator will also
56 raise StopIteration. There used to be various counterexamples to
57 this behavior, which could caused confusion or subtle program
58 breakage, without any benefits. (Note that this is still an
59 iterator's responsibility; the iterator framework does not enforce
60 this.)
61
Mark Hammondc0e35152002-07-16 01:32:30 +000062- Ctrl+C handling on Windows has been made more consistent with
63 other platforms. KeyboardInterrupt can now reliably be caught,
Tim Petersf47630f2002-08-01 02:34:51 +000064 and Ctrl+C at an interative prompt no longer terminates the
Mark Hammondc0e35152002-07-16 01:32:30 +000065 process under NT/2k/XP (it never did under Win9x). Ctrl+C will
Tim Petersf47630f2002-08-01 02:34:51 +000066 interrupt time.sleep() in the main thread, and any child processes
67 created via the popen family are also interrupted (as generally
Mark Hammondc0e35152002-07-16 01:32:30 +000068 happens on for Linux/Unix). [SF bugs 231273, 439992 and 581232]
69
Raymond Hettinger5a04aec2002-06-25 00:25:30 +000070- Slices and repetitions of buffer objects now consistently return
71 a string. Formerly, strings would be returned most of the time,
72 but a buffer object would be returned when the repetition count
73 was one or when the slice range was all inclusive.
74
Guido van Rossumc7c36502002-06-21 01:29:25 +000075- The __slots__ variable can now mention "private" names, and the
76 right thing will happen (e.g. __slots__ = ["__foo"]).
77
Walter Dörwald3430d702002-06-17 10:43:59 +000078- Unicode objects in sys.path are no longer ignored but treated
79 as directory names.
80
Guido van Rossum9562bcf2002-06-14 21:31:18 +000081- The built-ins slice() and buffer() are now callable types. The
82 types classobj (formerly class), code, function, instance, and
83 instancemethod (formerly instance-method), which have no built-in
84 names but are accessible through the types module, are now also
85 callable. The type dict-proxy is renamed to dictproxy.
86
Neal Norwitz1f68fc72002-06-14 00:50:42 +000087- Fixed string.startswith and string.endswith builtin methods
88 so they accept negative indices. [SF bug 493951]
89
Guido van Rossumc5fe5eb2002-06-12 03:45:21 +000090- Fixed a bug with a continue inside a try block and a yield in the
91 finally clause. [SF bug 567538]
92
Michael W. Hudson5efaf7e2002-06-11 10:55:12 +000093- Most builtin sequences now support "extended slices", i.e. slices
Guido van Rossum2e82e712002-06-13 11:41:07 +000094 with a third "stride" parameter. For example, "hello world"[::-1]
95 gives "dlrow olleh".
Michael W. Hudson5efaf7e2002-06-11 10:55:12 +000096
Guido van Rossum9f7549b2002-06-10 21:39:42 +000097- Cycles going through the __class__ link of a new-style instance are
98 now detected by the garbage collector.
99
Guido van Rossum9923ffe2002-06-04 19:52:53 +0000100- Classes using __slots__ are now properly garbage collected.
101 [SF bug 519621]
102
103- Tightened the __slots__ rules: a slot name must be a valid Python
104 identifier.
105
Guido van Rossum2e4e0262002-06-04 05:58:34 +0000106- The constructor for the module type now requires a name argument and
107 takes an optional docstring argument. Previously, this constructor
108 ignored its arguments. As a consequence, deriving a class from a
109 module (not from the module type) is now illegal; previously this
110 created an unnamed module, just like invoking the module type did.
111 [SF bug 563060]
112
Neal Norwitzd68f5172002-05-29 15:54:55 +0000113- A new warning PendingDeprecationWarning was added to provide
114 direction on features which are in the process of being deprecated.
115 The warning will not be printed by default. To see the pending
116 deprecations, use -Walways::PendingDeprecationWarning::
117 as a command line option or warnings.filterwarnings() in code.
118
Neal Norwitz32a7e7f2002-05-31 19:58:02 +0000119- A new type object, 'basestring', is added. This is a common base type
Guido van Rossumcacfc072002-05-24 19:01:59 +0000120 for 'str' and 'unicode', and can be used instead of
121 types.StringTypes, e.g. to test whether something is "a string":
Neal Norwitz32a7e7f2002-05-31 19:58:02 +0000122 isinstance(x, basestring) is True for Unicode and 8-bit strings. This
Guido van Rossumcacfc072002-05-24 19:01:59 +0000123 is an abstract base class and cannot be instantiated directly.
124
Fred Draked0ba6362002-05-02 21:28:26 +0000125- Deprecated features of xrange objects have been removed as
126 promised. The start, stop, and step attributes and the tolist()
127 method no longer exist. xrange repetition and slicing have been
128 removed.
129
Guido van Rossum7dab2422002-04-26 19:40:56 +0000130- New builtin function enumerate(x), from PEP 279. Example:
131 enumerate("abc") is an iterator returning (0,"a"), (1,"b"), (2,"c").
132 The argument can be an arbitrary iterable object.
133
Neil Schemenauer89e3ee02002-04-26 01:58:53 +0000134- The assert statement no longer tests __debug__ at runtime. This means
135 that assert statements cannot be disabled by assigning a false value
136 to __debug__.
137
Walter Dörwald068325e2002-04-15 13:36:47 +0000138- A method zfill() was added to str and unicode, that fills a numeric
139 string to the left with zeros. For example,
140 "+123".zfill(6) -> "+00123".
141
Guido van Rossum862fe3c2002-04-15 12:36:47 +0000142- Complex numbers supported divmod() and the // and % operators, but
143 these make no sense. Since this was documented, they're being
144 deprecated now.
145
Guido van Rossum26dd8302002-04-26 20:11:29 +0000146- String and unicode methods lstrip(), rstrip() and strip() now take
147 an optional argument that specifies the characters to strip. For
148 example, "Foo!!!?!?!?".rstrip("?!") -> "Foo".
Guido van Rossum49042042002-04-13 00:59:05 +0000149
Guido van Rossumc69343b2002-04-12 19:22:48 +0000150- Added a new dict method pop(key). This removes and returns the
151 value corresponding to key. [SF patch #539949]
152
Guido van Rossum8ace1ab2002-04-06 01:05:01 +0000153- Changed new-style class instantiation so that when C's __new__
154 method returns something that's not a C instance, its __init__ is
155 not called. [SF bug #537450]
156
Guido van Rossum181e41a2002-04-06 00:23:25 +0000157- Fixed super() to work correctly with class methods. [SF bug #535444]
158
Guido van Rossum47834462002-04-04 15:21:33 +0000159- A new built-in type, bool, has been added, as well as built-in
160 names for its two values, True and False. Comparisons and sundry
161 other operations that return a truth value have been changed to
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000162 return a bool instead. Read PEP 285 for an explanation of why this
Guido van Rossum47834462002-04-04 15:21:33 +0000163 is backward compatible.
164
Guido van Rossum95b62a62002-03-29 01:07:24 +0000165- Fixed two bugs reported as SF #535905: under certain conditions,
166 deallocating a deeply nested structure could cause a segfault in the
167 garbage collector, due to interaction with the "trashcan" code;
168 access to the current frame during destruction of a local variable
169 could access a pointer to freed memory.
170
Guido van Rossumfe0ca4a2002-06-18 21:20:13 +0000171- The optional object allocator ("pymalloc") has been enabled by
172 default. The recommended practice for memory allocation and
173 deallocation has been streamlined. A header file is included,
174 Misc/pymemcompat.h, which can be bundled with 3rd party extensions
175 and lets them use the same API with Python versions from 1.5.2
176 onwards.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000177
Guido van Rossum8c842552002-03-14 23:05:54 +0000178- If you try to pickle an instance of a class that has __slots__ but
179 doesn't define or override __getstate__, a TypeError is now raised.
180 This is done by adding a bozo __getstate__ to the class that always
181 raises TypeError. (Before, this would appear to be pickled, but the
182 state of the slots would be lost.)
183
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +0000184- PyErr_Display will provide file and line information for all exceptions
185 that have an attribute print_file_and_line, not just SyntaxErrors.
186
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000187- The UTF-8 codec will now encode and decode Unicode surrogates
188 correctly and without raising exceptions for unpaired ones.
189
Neal Norwitz649b7592002-01-01 19:07:13 +0000190- file.xreadlines() now raises a ValueError if the file is closed:
191 Previously, an xreadlines object was returned which would raise
192 a ValueError when the xreadlines.next() method was called.
193
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000194- sys.exit() inadvertently allowed more than one argument.
Neal Norwitz0c766a02002-03-27 13:03:09 +0000195 An exception will now be raised if more than one argument is used.
196
Tim Petersaf8446f2001-12-21 21:36:50 +0000197Extension modules
198
Guido van Rossumb57089c2002-08-06 16:20:26 +0000199- The xreadlines module is slated for obsolescence.
200
Guido van Rossum79f0a102002-07-23 03:32:08 +0000201- The strptime function in the time module is now always available (a
202 Python implementation is used when the C library doesn't define it).
203
Guido van Rossum9562bcf2002-06-14 21:31:18 +0000204- The 'new' module is no longer an extension, but a Python module that
205 only exists for backwards compatibility. Its contents are no longer
206 functions but callable type objects.
207
Tim Peters81b92512002-04-29 01:37:32 +0000208- The bsddb.*open functions can now take 'None' as a filename.
Anthony Baxter83888952002-04-23 02:11:05 +0000209 This will create a temporary in-memory bsddb that won't be
Tim Peters81b92512002-04-29 01:37:32 +0000210 written to disk.
Anthony Baxter83888952002-04-23 02:11:05 +0000211
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000212- posix.lchown, posix.killpg, posix.mknod, and posix.getpgid have been
213 added where available.
Martin v. Löwis06a83e92002-04-14 10:19:44 +0000214
Martin v. Löwis2e64c342002-03-27 18:49:02 +0000215- The locale module now exposes the C library's gettext interface.
216
Tim Petersfbf74f22002-03-14 19:06:01 +0000217- A security hole ("double free") was found in zlib-1.1.3, a popular
218 third party compression library used by some Python modules. The
219 hole was quickly plugged in zlib-1.1.4, and the Windows build of
220 Python now ships with zlib-1.1.4.
221
Martin v. Löwis688357e2002-04-08 21:28:20 +0000222- pwd, grp, and resource return enhanced tuples now, with symbolic
223 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +0000224
Martin v. Löwis99866332002-03-01 10:27:01 +0000225- array.array is now a type object. A new format character
226 'u' indicates Py_UNICODE arrays. For those, .tounicode and
227 .fromunicode methods are available. Arrays now support __iadd__
228 and __imul__.
229
Neal Norwitze790eae2002-01-01 21:14:12 +0000230- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +0000231 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
232 is called.
233
Michael W. Hudson34f20ea2002-05-27 15:08:24 +0000234- signal.sigpending, signal.sigprocmask and signal.sigsuspend have
235 been added where available.
236
Tim Petersaf8446f2001-12-21 21:36:50 +0000237Library
238
Guido van Rossum4a57c332002-08-02 18:05:20 +0000239- New "algorithms" module: heapq, implements a heap queue. Thanks to
240 Kevin O'Connor for the code and François Pinard for an entertaining
241 write-up explaining the theory and practical uses of heaps.
242
Marc-André Lemburg58e2ff22002-07-12 14:40:04 +0000243- New encoding for the Palm OS character set: palmos.
244
Tim Peters943382c2002-07-07 03:59:34 +0000245- binascii.crc32() and the zipfile module had problems on some 64-bit
246 platforms. These have been fixed. On a platform with 8-byte C longs,
247 crc32() now returns a signed-extended 4-byte result, so that its value
248 as a Python int is equal to the value computed a 32-bit platform.
249
Martin v. Löwis7d650ca2002-06-30 15:05:00 +0000250- xml.dom.minidom.toxml and toprettyxml now take an optional encoding
251 argument.
252
Guido van Rossum9f7549b2002-06-10 21:39:42 +0000253- Some fixes in the copy module: when an object is copied through its
254 __reduce__ method, there was no check for a __setstate__ method on
255 the result [SF patch 565085]; deepcopy should treat instances of
256 custom metaclasses the same way it treats instances of type 'type'
257 [SF patch 560794].
258
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000259- Sockets now support timeout mode. After s.settimeout(T), where T is
260 a float expressing seconds, subsequent operations raise an exception
261 if they cannot be completed within T seconds. To disable timeout
Guido van Rossum79f0a102002-07-23 03:32:08 +0000262 mode, use s.settimeout(None). There's also a module function,
263 socket.setdefaulttimeout(T), which sets the default for all sockets
264 created henceforth.
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000265
266- getopt.gnu_getopt was added. This supports GNU-style option
267 processing, where options can be mixed with non-option arguments.
Martin v. Löwis446a25f2002-06-06 10:58:36 +0000268
Michael W. Hudsonb0dc1a32002-06-04 18:27:35 +0000269- Stop using strings for exceptions. String objects used for
270 exceptions are now classes deriving from Exception. The objects
271 changed were: Tkinter.TclError, bdb.BdbQuit, macpath.norm_error,
272 tabnanny.NannyNag, and xdrlib.Error.
Neal Norwitzb5b5a262002-06-04 17:14:07 +0000273
Walter Dörwald474458d2002-06-04 15:16:29 +0000274- Constants BOM_UTF8, BOM_UTF16, BOM_UTF16_LE, BOM_UTF16_BE,
275 BOM_UTF32, BOM_UTF32_LE and BOM_UTF32_BE that represent the Byte
276 Order Mark in UTF-8, UTF-16 and UTF-32 encodings for little and
277 big endian systems were added to the codecs module. The old names
278 BOM32_* and BOM64_* were off by a factor of 2.
279
Guido van Rossumf9257822002-06-18 20:43:18 +0000280- Added conversion functions math.degrees() and math.radians().
Raymond Hettinger87f59ee2002-05-13 04:17:32 +0000281
Raymond Hettinger9b1df1d2002-05-12 06:07:21 +0000282- ftplib.retrlines() now tests for callback is None rather than testing
283 for False. Was causing an error when given a callback object which
284 was callable but also returned len() as zero. The change may
285 create new breakage if the caller relied on the undocumented behavior
286 and called with callback set to [] or some other False value not
287 identical to None.
288
Tim Peters46c04e12002-05-05 20:40:00 +0000289- random.gauss() uses a piece of hidden state used by nothing else,
290 and the .seed() and .whseed() methods failed to reset it. In other
291 words, setting the seed didn't completely determine the sequence of
292 results produced by random.gauss(). It does now. Programs repeatedly
293 mixing calls to a seed method with calls to gauss() may see different
294 results now.
295
Fred Drake7f781c92002-05-01 20:33:53 +0000296- The pickle.Pickler class grew a clear_memo() method to mimic that
297 provided by cPickle.Pickler.
298
Tim Peters81b92512002-04-29 01:37:32 +0000299- difflib's SequenceMatcher class now does a dynamic analysis of
300 which elements are so frequent as to constitute noise. For
301 comparing files as sequences of lines, this generally works better
302 than the IS_LINE_JUNK function, and function ndiff's linejunk
303 argument defaults to None now as a result. A happy benefit is
304 that SequenceMatcher may run much faster now when applied
305 to large files with many duplicate lines (for example, C program
306 text with lots of repeated "}" and "return NULL;" lines).
307
Guido van Rossum256705b2002-04-23 13:29:43 +0000308- New Text.dump() method in Tkinter module.
309
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000310- New distutils commands for building packagers were added to
311 support pkgtool on Solaris and swinstall on HP-UX.
312
313- distutils now has a new abstract binary packager base class
314 command/bdist_packager, which simplifies writing packagers.
315 This will hopefully provide the missing bits to encourage
316 people to submit more packagers, e.g. for Debian, FreeBSD
317 and other systems.
318
Guido van Rossumf9257822002-06-18 20:43:18 +0000319- The UTF-16, -LE and -BE stream readers now raise a
320 NotImplementedError for all calls to .readline(). Previously, they
321 used to just produce garbage or fail with an encoding error --
322 UTF-16 is a 2-byte encoding and the C lib's line reading APIs don't
Marc-André Lemburg4179a012002-04-05 12:15:05 +0000323 work well with these.
324
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000325- compileall now supports quiet operation.
326
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000327- The BaseHTTPServer now implements optional HTTP/1.1 persistent
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000328 connections.
329
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000330- socket module: the SSL support was broken out of the main
331 _socket module C helper and placed into a new _ssl helper
332 which now gets imported by socket.py if available and working.
333
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000334- encodings package: added aliases for all supported IANA character
335 sets
336
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000337- ftplib: to safeguard the user's privacy, anonymous login will use
338 "anonymous@" as default password, rather than the real user and host
339 name.
340
Fred Drake36736122002-01-10 13:50:31 +0000341- webbrowser: tightened up the command passed to os.system() so that
342 arbitrary shell code can't be executed because a bogus URL was
343 passed in.
344
Tim Peters11bd9942002-02-01 00:52:29 +0000345- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000346 gettext.find an optional all argument. Translations will now fallback
347 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000348
Martin v. Löwis9668b932002-01-12 11:27:42 +0000349- distutils bdist commands now offer a --skip-build option.
350
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000351- warnings.warn now accepts a Warning instance as first argument.
352
Fred Drakefed7e852002-04-04 19:36:15 +0000353- The xml.sax.expatreader.ExpatParser class will no longer create
354 circular references by using itself as the locator that gets passed
355 to the content handler implementation. [SF bug #535474]
356
Barry Warsaw47f3e2c2002-05-20 00:14:24 +0000357- The email.Parser.Parser class now properly parses strings regardless
358 of their line endings, which can be any of \r, \n, or \r\n (CR, LF,
359 or CRLF). Also, the Header class's constructor default arguments
360 has changed slightly so that an explicit maxlinelen value is always
361 honored.
362
Tim Petersaf8446f2001-12-21 21:36:50 +0000363Tools/Demos
364
Fred Drake40813b12002-08-05 15:24:19 +0000365- IDLE supports the new encoding declarations (PEP 263); it can also
366 deal with legacy 8-bit files if they use the locale's encoding. It
367 allows non-ASCII strings in the interactive shell and executes them
368 in the locale's encoding.
Martin v. Löwis98ce7b72002-08-05 15:11:26 +0000369
Marc-André Lemburg46260092002-04-04 16:17:11 +0000370- freeze.py now produces binaries which can import shared modules,
371 unlike before when this failed due to missing symbol exports in
372 the generated binary.
373
Tim Petersaf8446f2001-12-21 21:36:50 +0000374Build
375
Tim Petersf47630f2002-08-01 02:34:51 +0000376- The public Python C API will generally be declared using PyAPI_FUNC
Neal Norwitz1389f3e2002-07-22 13:21:10 +0000377 and PyAPI_DATA macros, while Python extension module init functions
378 will be declared with PyMODINIT_FUNC. DL_EXPORT/DL_IMPORT macros
379 are deprecated.
380
Tim Petersc6a3ff62002-07-08 22:11:52 +0000381- A bug was fixed that could cause COUNT_ALLOCS builds to segfault, or
382 get into infinite loops, when a new-style class got garbage-collected.
383 Unfortunately, to avoid this, the way COUNT_ALLOCS works requires
384 that new-style classes be immortal in COUNT_ALLOCS builds. Note that
385 COUNT_ALLOCS is not enabled by default, in either release or debug
386 builds, and that new-style classes are immortal only in COUNT_ALLOCS
387 builds.
388
Tim Peters943382c2002-07-07 03:59:34 +0000389- Compiling out the cyclic garbage collector is no longer an option.
390 The old symbol WITH_CYCLE_GC is now ignored, and Python.h arranges
391 that it's always defined (for the benefit of any extension modules
392 that may be conditionalizing on it). A bonus is that any extension
393 type participating in cyclic gc can choose to participate in the
394 Py_TRASHCAN mechanism now too; in the absence of cyclic gc, this used
395 to require editing the core to teach the trashcan mechanism about the
396 new type.
397
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000398- According to Annex F of the current C standard,
Tim Peters1de41bf2002-07-03 03:31:20 +0000399
400 The Standard C macro HUGE_VAL and its float and long double analogs,
401 HUGE_VALF and HUGE_VALL, expand to expressions whose values are
402 positive infinities.
403
404 Python only uses the double HUGE_VAL, and only to #define its own symbol
405 Py_HUGE_VAL. Some platforms have incorrect definitions for HUGE_VAL.
406 pyport.h used to try to worm around that, but the workarounds triggered
407 other bugs on other platforms, so we gave up. If your platform defines
408 HUGE_VAL incorrectly, you'll need to #define Py_HUGE_VAL to something
409 that works on your platform. The only instance of this I'm sure about
410 is on an unknown subset of Cray systems, described here:
411
412 http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm
413
414 Presumably 2.3a1 breaks such systems. If anyone uses such a system, help!
415
Martin v. Löwisa3fb4f72002-06-09 13:33:54 +0000416- The configure option --without-doc-strings can be used to remove the
417 doc strings from the builtin functions and modules; this reduces the
418 size of the executable.
419
Tim Peters639295f2002-04-21 07:30:30 +0000420- XXX WITH_UNIVERSAL_NEWLINES Somebody fill this in; the PEP doesn't
421 say how or when to configure it, or how to turn it off.
422
Martin v. Löwis1142de32002-03-29 16:28:31 +0000423- On Unix, a shared libpython2.3.so can be created with --enable-shared.
424
Tim Peters8deda702002-03-30 10:06:07 +0000425- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
426 preprocessor symbols were eliminated. The internal decisions they
427 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000428
Fred Drake7d28b732002-05-02 21:17:00 +0000429- The tools used to build the documentation now work under Cygwin as
430 well as Unix.
431
Skip Montanaro57454e52002-06-14 20:30:31 +0000432- The bsddb and dbm module builds have been changed to try and avoid version
433 skew problems and disable linkage with Berkeley DB 1.85 unless the
434 installer knows what s/he's doing. See the section on building these
435 modules in the README file for details.
436
Tim Petersaf8446f2001-12-21 21:36:50 +0000437C API
438
Thomas Heller085358a2002-07-29 14:27:41 +0000439- New functions PyErr_SetExcFromWindowsErr() and
440 PyErr_SetExcFromWindowsErrWithFilename(). Similar to
441 PyErr_SetFromWindowsErrWithFilename() and
442 PyErr_SetFromWindowsErr(), but they allow to specify
443 the exception type to raise. Available on Windows.
444
Tim Peters7c321a82002-07-09 02:57:01 +0000445- Py_FatalError() is now declared as taking a const char* argument. It
446 was previously declared without const. This should not affect working
447 code.
448
Martin v. Löwis01f94bd2002-05-08 08:44:21 +0000449- Added new macro PySequence_ITEM(o, i) that directly calls
450 sq_item without rechecking that o is a sequence and without
451 adjusting for negative indices.
452
Fred Draked0ba6362002-05-02 21:28:26 +0000453- PyRange_New() now raises ValueError if the fourth argument is not 1.
454 This is part of the removal of deprecated features of the xrange
455 object.
456
Guido van Rossum517c7d42002-04-26 02:49:14 +0000457- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
458 coercion if both arguments have the same type but this type has the
459 CHECKTYPES flag set. This is to better support proxies.
460
Neil Schemenauer9344b142002-04-12 23:00:08 +0000461- The type of tp_free has been changed from "void (*)(PyObject *)" to
462 "void (*)(void *)".
463
464- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
465
Guido van Rossum0986d822002-04-08 01:38:42 +0000466- A type can now inherit its metatype from its base type. Previously,
467 when PyType_Ready() was called, if ob_type was found to be NULL, it
468 was always set to &PyType_Type; now it is set to base->ob_type,
469 where base is tp_base, defaulting to &PyObject_Type.
470
471- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
472
Neil Schemenauerc9abc1d2002-05-08 14:14:41 +0000473- The PyCore_* family of APIs have been removed.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000474
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000475- The "u#" parser marker will now pass through Unicode objects as-is
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000476 without going through the buffer API.
477
Martin v. Löwis7198a522002-01-01 19:59:11 +0000478- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
479
Tim Peters10a3bb52001-12-25 19:07:38 +0000480- An old #define of ANY as void has been removed from pyport.h. This
481 hasn't been used since Python's pre-ANSI days, and the #define has
482 been marked as obsolete since then. SF bug 495548 says it created
483 conflicts with other packages, so keeping it around wasn't harmless.
484
Tim Petersaf8446f2001-12-21 21:36:50 +0000485- Because Python's magic number scheme broke on January 1st, we decided
486 to stop Python development. Thanks for all the fish!
487
Tim Petersfb05db22002-03-11 00:24:00 +0000488- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000489 scheme to a new one. See Python/import.c for details.
490
Tim Petersaf8446f2001-12-21 21:36:50 +0000491New platforms
492
Martin v. Löwisf90ae202002-06-11 06:22:31 +0000493- AtheOS is now supported.
494
Andrew MacIntyre161ad0e2002-08-04 07:25:58 +0000495- the EMX runtime environment on OS/2 is now supported.
496
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000497- GNU/Hurd is now supported.
498
Tim Petersaf8446f2001-12-21 21:36:50 +0000499Tests
500
501Windows
502
Tim Peters08e72952002-04-16 20:48:01 +0000503- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
504 of that has been fixed in the installer (disabled Wise's "delete in-
505 use files" uninstall option).
506
Guido van Rossum181e41a2002-04-06 00:23:25 +0000507- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
508
Tim Peters33187922002-04-04 20:02:04 +0000509- The installer now installs Start menu shortcuts under (the local
510 equivalent of) "All Users" when doing an Admin install.
511
Tim Petersfb05db22002-03-11 00:24:00 +0000512- file.truncate([newsize]) now works on Windows for all newsize values.
513 It used to fail if newsize didn't fit in 32 bits, reflecting a
514 limitation of MS _chsize (which is no longer used).
515
Tim Petersab034fa2002-02-01 11:27:43 +0000516- os.waitpid() is now implemented for Windows, and can be used to block
517 until a specified process exits. This is similar to, but not exactly
518 the same as, os.waitpid() on POSIX systems. If you're waiting for
519 a specific process whose pid was obtained from one of the spawn()
520 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000521 See the docs for details. The docs were changed to clarify that
522 spawn functions return, and waitpid requires, a process handle on
523 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000524
Tim Peters11bd9942002-02-01 00:52:29 +0000525- New tempfile.TemporaryFile implementation for Windows: this doesn't
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000526 need a TemporaryFileWrapper wrapper anymore, and should be immune
Tim Peters11bd9942002-02-01 00:52:29 +0000527 to a nasty problem: before 2.3, if you got a temp file on Windows, it
528 got wrapped in an object whose close() method first closed the
529 underlying file, then deleted the file. This usually worked fine.
530 However, the spawn family of functions on Windows create (at a low C
531 level) the same set of open files in the spawned process Q as were
532 open in the spawning process P. If a temp file f was among them, then
533 doing f.close() in P first closed P's C-level file handle on f, but Q's
534 C-level file handle on f remained open, so the attempt in P to delete f
535 blew up with a "Permission denied" error (Windows doesn't allow
536 deleting open files). This was surprising, subtle, and difficult to
537 work around.
538
539- The os module now exports all the symbolic constants usable with the
540 low-level os.open() on Windows: the new constants in 2.3 are
541 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
542 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
543 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
544 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
545 (so specify both if you want both; note that neither is useful unless
546 specified with O_CREAT too).
547
Tim Petersaf8446f2001-12-21 21:36:50 +0000548Mac
549
550
Tim Peters909c0912001-12-14 23:16:18 +0000551What's New in Python 2.2 final?
552Release date: 21-Dec-2001
553===============================
554
555Type/class unification and new-style classes
556
Barry Warsaw52acb492001-12-21 20:04:22 +0000557- pickle.py, cPickle: allow pickling instances of new-style classes
558 with a custom metaclass.
559
Tim Peters909c0912001-12-14 23:16:18 +0000560Core and builtins
561
Barry Warsaw52acb492001-12-21 20:04:22 +0000562- weakref proxy object: when comparing, unwrap both arguments if both
563 are proxies.
564
Tim Peters909c0912001-12-14 23:16:18 +0000565Extension modules
566
Barry Warsaw52acb492001-12-21 20:04:22 +0000567- binascii.b2a_base64(): fix a potential buffer overrun when encoding
568 very short strings.
569
570- cPickle: the obscure "fast" mode was suspected of causing stack
571 overflows on the Mac. Hopefully fixed this by setting the recursion
572 limit much smaller. If the limit is too low (it only affects
573 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
574 when compiling cPickle.c (or in pyconfig.h).
575
Tim Peters909c0912001-12-14 23:16:18 +0000576Library
577
Barry Warsaw52acb492001-12-21 20:04:22 +0000578- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
579 close or delete time).
580
581- rfc822.py: fixed a bug where the address '<>' was converted to None
582 instead of an empty string (also fixes the email.Utils module).
583
584- xmlrpclib.py: version 1.0.0; uses precision for doubles.
585
586- test suite: the pickle and cPickle tests were not executing any code
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000587 when run from the standard regression test.
Barry Warsaw52acb492001-12-21 20:04:22 +0000588
Tim Peters909c0912001-12-14 23:16:18 +0000589Tools/Demos
590
591Build
592
593C API
594
595New platforms
596
597Tests
598
599Windows
600
Barry Warsaw52acb492001-12-21 20:04:22 +0000601- distutils package: fixed broken Windows installers (bdist_wininst).
602
603- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
604 instances are deleted at process exit time.
605
606- socket.py: prevent mysterious warnings when socket instances are
607 deleted at process exit time.
608
609- posixmodule.c: fix a Windows crash with stat() of a filename ending
610 in backslash.
611
Tim Peters909c0912001-12-14 23:16:18 +0000612Mac
613
Barry Warsaw52acb492001-12-21 20:04:22 +0000614- The Carbon toolbox modules have been upgraded to Universal Headers
615 3.4, and experimental CoreGraphics and CarbonEvents modules have
616 been added. All only for framework-enabled MacOSX.
617
Tim Peters909c0912001-12-14 23:16:18 +0000618
Tim Peters6272dfd2001-12-13 19:34:00 +0000619What's New in Python 2.2c1?
620Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000621===========================
622
623Type/class unification and new-style classes
624
Barry Warsaw06557452001-12-14 20:47:12 +0000625- Guido's tutorial introduction to the new type/class features has
626 been extensively updated. See
627
628 http://www.python.org/2.2/descrintro.html
629
630 That remains the primary documentation in this area.
631
Guido van Rossum33bab012001-12-05 22:45:48 +0000632- Fixed a leak: instance variables declared with __slots__ were never
633 deleted!
634
Guido van Rossum4b800852001-12-03 00:54:52 +0000635- The "delete attribute" method of descriptor objects is called
636 __delete__, not __del__. In previous releases, it was mistakenly
637 called __del__, which created an unfortunate overloading condition
638 with finalizers. (The "get attribute" and "set attribute" methods
639 are still called __get__ and __set__, respectively.)
640
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000641- Some subtle issues with the super built-in were fixed:
642
643 (a) When super itself is subclassed, its __get__ method would still
644 return an instance of the base class (i.e., of super).
645
646 (b) super(C, C()).__class__ would return C rather than super. This
647 is confusing. To fix this, I decided to change the semantics of
648 super so that it only applies to code attributes, not to data
649 attributes. After all, overriding data attributes is not
650 supported anyway.
651
652 (c) The __get__ method didn't check whether the argument was an
653 instance of the type used in creation of the super instance.
654
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000655- Previously, hash() of an instance of a subclass of a mutable type
656 (list or dictionary) would return some value, rather than raising
657 TypeError. This has been fixed. Also, directly calling
658 dict.__hash__ and list.__hash__ now raises the same TypeError
659 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000660
Guido van Rossumd331cb52001-12-05 19:46:42 +0000661- New-style objects now support deleting their __dict__. This is for
662 all intents and purposes equivalent to assigning a brand new empty
663 dictionary, but saves space if the object is not used further.
664
Tim Petersb3c9af12001-11-17 00:21:57 +0000665Core and builtins
666
Tim Peters3caca232001-12-06 06:23:26 +0000667- -Qnew now works as documented in PEP 238: when -Qnew is passed on
668 the command line, all occurrences of "/" use true division instead
669 of classic division. See the PEP for details. Note that "all"
670 means all instances in library and 3rd-party modules, as well as in
671 your own code. As the PEP says, -Qnew is intended for use only in
672 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000673 Note that test_coercion.py in the standard Python test suite fails
674 under -Qnew; this is expected, and won't be repaired until true
675 division becomes the default (in the meantime, test_coercion is
676 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000677
Fred Drake6c01e252001-12-14 17:08:12 +0000678- complex() now only allows the first argument to be a string
679 argument, and raises TypeError if either the second arg is a string
680 or if the second arg is specified when the first is a string.
681
Tim Petersb3c9af12001-11-17 00:21:57 +0000682Extension modules
683
Martin v. Löwis560da622001-11-24 09:24:51 +0000684- gc.get_referents was renamed to gc.get_referrers.
685
Tim Petersb3c9af12001-11-17 00:21:57 +0000686Library
687
Tim Peters25059d32001-12-07 20:35:43 +0000688- Functions in the os.spawn() family now release the global interpreter
689 lock around calling the platform spawn. They should always have done
690 this, but did not before 2.2c1. Multithreaded programs calling
691 an os.spawn function with P_WAIT will no longer block all Python threads
692 until the spawned program completes. It's possible that some programs
693 relies on blocking, although more likely by accident than by design.
694
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000695- webbrowser defaults to netscape.exe on OS/2 now.
696
Martin v. Löwis652e1912001-11-25 14:50:56 +0000697- Tix.ResizeHandle exposes detach_widget, hide, and show.
698
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000699- The charset alias windows_1252 has been added.
700
Barry Warsaw06557452001-12-14 20:47:12 +0000701- types.StringTypes is a tuple containing the defined string types;
702 usually this will be (str, unicode), but if Python was compiled
703 without Unicode support it will be just (str,).
704
705- The pulldom and minidom modules were synchronized to PyXML.
706
Tim Petersb3c9af12001-11-17 00:21:57 +0000707Tools/Demos
708
Barry Warsaw06557452001-12-14 20:47:12 +0000709- A new script called Tools/scripts/google.py was added, which fires
710 off a search on Google.
711
Tim Petersb3c9af12001-11-17 00:21:57 +0000712Build
713
Barry Warsaw06557452001-12-14 20:47:12 +0000714- Note that release builds of Python should arrange to define the
715 preprocessor symbol NDEBUG on the command line (or equivalent).
716 In the 2.2 pre-release series we tried to define this by magic in
717 Python.h instead, but it proved to cause problems for extension
718 authors. The Unix, Windows and Mac builds now all define NDEBUG in
719 release builds via cmdline (or equivalent) instead. Ports to
720 other platforms should do likewise.
721
Jack Jansen1999ef42001-12-06 21:47:20 +0000722- It is no longer necessary to use --with-suffix when building on a
723 case-insensitive file system (such as Mac OS X HFS+). In the build
724 directory an extension is used, but not in the installed python.
725
Tim Petersb3c9af12001-11-17 00:21:57 +0000726C API
727
Tim Petersf582b822001-12-11 18:51:08 +0000728- New function PyDict_MergeFromSeq2() exposes the builtin dict
729 constructor's logic for updating a dictionary from an iterable object
730 producing key-value pairs.
731
Tim Peterscffed4b2001-11-29 03:26:37 +0000732- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000733 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000734 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
735 dump core in some bad cases. This has been repaired. As a result,
736 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
737 previously went unchallenged.
738
Tim Petersb3c9af12001-11-17 00:21:57 +0000739New platforms
740
741Tests
742
743Windows
744
745Mac
746
Jack Jansenffa260f2001-12-06 21:14:00 +0000747- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
748 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000749
Barry Warsaw06557452001-12-14 20:47:12 +0000750- Changed logic for finding python home in Mac OS X framework Pythons.
751 Now sys.executable points to the executable again, in stead of to
752 the shared library. The latter is used only for locating the python
753 home.
754
755
Tim Peters84362bc2001-10-19 17:55:30 +0000756What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000757Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000758===========================
759
760Type/class unification and new-style classes
761
Guido van Rossum3d27df02001-11-15 20:27:54 +0000762- Multiple inheritance mixing new-style and classic classes in the
763 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000764
765 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000766 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000767
768 The MRO (method resolution order) for each base class is respected
769 according to its kind, but the MRO for the derived class is computed
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000770 using new-style MRO rules if any base class is a new-style class.
Tim Peters76f7fe32001-11-15 20:02:21 +0000771 This needs to be documented.
772
Tim Petersa427a2b2001-10-29 22:25:45 +0000773- The new builtin dictionary() constructor, and dictionary type, have
774 been renamed to dict. This reflects a decade of common usage.
775
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000776- dict() now accepts an iterable object producing 2-sequences. For
777 example, dict(d.items()) == d for any dictionary d. The argument,
778 and the elements of the argument, can be any iterable objects.
779
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000780- New-style classes can now have a __del__ method, which is called
781 when the instance is deleted (just like for classic classes).
782
Guido van Rossum12d955c2001-10-26 14:56:06 +0000783- Assignment to object.__dict__ is now possible, for objects that are
784 instances of new-style classes that have a __dict__ (unless the base
785 class forbids it).
786
Guido van Rossumc8e56452001-10-22 00:43:43 +0000787- Methods of built-in types now properly check for keyword arguments
788 (formerly these were silently ignored). The only built-in methods
789 that take keyword arguments are __call__, __init__ and __new__.
790
Guido van Rossum86443212001-10-27 22:28:54 +0000791- The socket function has been converted to a type; see below.
792
Tim Peters84362bc2001-10-19 17:55:30 +0000793Core and builtins
794
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000795- Assignment to __debug__ raises SyntaxError at compile-time. This
796 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000797 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000798
Guido van Rossum12d955c2001-10-26 14:56:06 +0000799- Clarified the error messages for unsupported operands to an operator
800 (like 1 + '').
801
Tim Peters84362bc2001-10-19 17:55:30 +0000802Extension modules
803
Tim Peters5ebfd362001-11-13 23:11:19 +0000804- mmap has a new keyword argument, "access", allowing a uniform way for
805 both Windows and Unix users to create read-only, write-through and
806 copy-on-write memory mappings. This was previously possible only on
807 Unix. A new keyword argument was required to support this in a
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000808 uniform way because the mmap() signatures had diverged across
Tim Peters5ebfd362001-11-13 23:11:19 +0000809 platforms. Thanks to Jay T Miller for repairing this!
810
Tim Peters169ded02001-11-03 19:57:21 +0000811- By default, the gc.garbage list now contains only those instances in
812 unreachable cycles that have __del__ methods; in 2.1 it contained all
813 instances in unreachable cycles. "Instances" here has been generalized
814 to include instances of both new-style and old-style classes.
815
Guido van Rossum12d955c2001-10-26 14:56:06 +0000816- The socket module defines a new method for socket objects,
817 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000818 send() until all data has been sent. Also, the socket function has
819 been converted to a subclassable type, like list and tuple (etc.)
820 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000821
822- Various bugfixes to the curses module. There is now a test suite
823 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000824
Guido van Rossum692adf12001-10-30 03:03:03 +0000825- binascii.b2a_base64 no longer places an arbitrary restriction of 57
826 bytes on its input.
827
Tim Peters84362bc2001-10-19 17:55:30 +0000828Library
829
Tim Peters5ebfd362001-11-13 23:11:19 +0000830- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000831 convenience function.
832
Tim Peters75335872001-11-03 19:35:43 +0000833- Symbolic group names in regular expressions must be unique. For
834 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
835 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000836 Python 2.2 detects this error at regexp compilation time;
837 previously, the error went undetected, and results were
838 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
839 pattern.subn() methods have been rewritten in C. Also, an
840 experimental function/method finditer() has been added, which works
841 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000842
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000843- Tix exposes more commands through the classes DirSelectBox,
844 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
845 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
846 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
847
Tim Peters98791af2001-10-23 01:59:54 +0000848- Traceback objects are now scanned by cyclic garbage collection, so
849 cycles created by casual use of sys.exc_info() no longer cause
850 permanent memory leaks (provided garbage collection is enabled).
851
Guido van Rossum49192142001-10-24 20:51:44 +0000852- os.extsep -- a new variable needed by the RISCOS support. It is the
853 separator used by extensions, and is '.' on all platforms except
854 RISCOS, where it is '/'. There is no need to use this variable
855 unless you have a masochistic desire to port your code to RISCOS.
856
Barry Warsaw012852b2001-11-16 16:17:27 +0000857- mimetypes.py has optional support for non-standard, but commonly
858 found types. guess_type() and guess_extension() now accept an
859 optional `strict' flag, defaulting to true, which controls whether
860 recognize non-standard types or not. A few non-standard types we
861 know about have been added. Also, when run as a script, there are
862 new -l and -e options.
863
864- statcache is now deprecated.
865
866- email.Utils.formatdate() now produces the preferred RFC 2822 style
867 dates with numeric timezones (it used to produce obsolete dates
868 hard coded to "GMT" timezone). An optional `localtime' flag is
869 added to produce dates in the local timezone, with daylight savings
870 time properly taken into account.
871
872- In pickle and cPickle, instead of masking errors in load() by
873 transforming them into SystemError, we let the original exception
874 propagate out. Also, implement support for __safe_for_unpickling__
875 in pickle, as it already was supported in cPickle.
876
Tim Peters84362bc2001-10-19 17:55:30 +0000877Tools/Demos
878
879Build
880
Barry Warsaw012852b2001-11-16 16:17:27 +0000881- The dbm module is built using libdb1 if available. The bsddb module
882 is built with libdb3 if available.
883
884- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
885
Tim Peters84362bc2001-10-19 17:55:30 +0000886C API
887
Tim Peters1fc240e2001-10-26 05:06:50 +0000888- New function PySequence_Fast_GET_SIZE() returns the size of a non-
889 NULL result from PySequence_Fast(), more quickly than calling
890 PySequence_Size().
891
Barry Warsaw012852b2001-11-16 16:17:27 +0000892- New argument unpacking function PyArg_UnpackTuple() added.
893
894- New functions PyObject_CallFunctionObjArgs() and
895 PyObject_CallMethodObjArgs() have been added to make it more
896 convenient and efficient to call functions and methods from C.
897
898- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
899 possible that this will propagate errors it didn't before.
900
901- New function PyObject_CheckReadBuffer(), which returns true if its
902 argument supports the single-segment readable buffer interface.
903
Tim Peters84362bc2001-10-19 17:55:30 +0000904New platforms
905
Guido van Rossum86443212001-10-27 22:28:54 +0000906- We've finally confirmed that this release builds on HP-UX 11.00,
907 *with* threads, and passes the test suite.
908
Tim Peters7a33d8b2001-11-05 02:51:07 +0000909- Thanks to a series of patches from Michael Muller, Python may build
910 again under OS/2 Visual Age C++.
911
Guido van Rossum49192142001-10-24 20:51:44 +0000912- Updated RISCOS port by Dietmar Schwertberger.
913
Tim Peters84362bc2001-10-19 17:55:30 +0000914Tests
915
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000916- Added a test script for the curses module. It isn't run automatically;
917 regrtest.py must be run with '-u curses' to enable it.
918
Tim Peters84362bc2001-10-19 17:55:30 +0000919Windows
920
Barry Warsaw012852b2001-11-16 16:17:27 +0000921Mac
922
923- PythonScript has been moved to unsupported and is slated to be
924 removed completely in the next release.
925
926- It should now be possible to build applets that work on both OS9 and
927 OSX.
928
929- The core is now linked with CoreServices not Carbon; as a side
930 result, default 8bit encoding on OSX is now ASCII.
931
932- Python should now build on OSX 10.1.1
933
Tim Peters84362bc2001-10-19 17:55:30 +0000934
Tim Petersabf925f2001-09-28 21:53:42 +0000935What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000936Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000937===========================
938
939Type/class unification and new-style classes
940
Guido van Rossum687ae002001-10-15 22:03:32 +0000941- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000942 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000943 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000944 remains: the __dict__ of a new-style class is a read-only proxy; you
945 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000946 __defined__ attribute of new-style types no longer exists, for lack
947 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000948 future a __cache__ may be resurrected with a similar function, if I
949 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000950
Tim Peters1c9ca872001-10-04 06:43:12 +0000951- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
952 always returned None, even when there was a class docstring).
953
954- doctest now finds and runs docstrings attached to new-style classes,
955 class methods, static methods, and properties.
956
Guido van Rossum9074ef62001-10-16 21:34:49 +0000957Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000958
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000959- A very subtle syntactical pitfall in list comprehensions was fixed.
960 For example: [a+b for a in 'abc', for b in 'def']. The comma in
961 this example is a mistake. Previously, this would silently let 'a'
962 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
963 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
964 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
965 Note that [a for a in <singleton>] is a convoluted way to say
966 [<singleton>] anyway, so it's not like any expressiveness is lost.
967
Guido van Rossum9074ef62001-10-16 21:34:49 +0000968- getattr(obj, name, default) now only catches AttributeError, as
969 documented, rather than returning the default value for all
970 exceptions (which could mask bugs in a __getattr__ hook, for
971 example).
972
Fred Drakecb7a6b52001-10-22 18:41:51 +0000973- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000974 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000975 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000976 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000977
Guido van Rossum1c486092001-10-19 02:05:35 +0000978- unicode(obj) now behaves more like str(obj), accepting arbitrary
979 objects, and calling a __unicode__ method if it exists.
980 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000981 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000982
Barry Warsawf6fb1712001-10-19 05:35:40 +0000983- isinstance() now allows any object as the first argument and a
984 class, a type or something with a __bases__ tuple attribute for the
985 second argument. The second argument may also be a tuple of a
986 class, type, or something with __bases__, in which case isinstance()
987 will return true if the first argument is an instance of any of the
988 things contained in the second argument tuple. E.g.
989
990 isinstance(x, (A, B))
991
992 returns true if x is an instance of A or B.
993
Guido van Rossum9074ef62001-10-16 21:34:49 +0000994Extension modules
995
996- thread.start_new_thread() now returns the thread ID (previously None).
997
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000998- binascii has now two quopri support functions, a2b_qp and b2a_qp.
999
Guido van Rossumc524d952001-10-19 01:31:59 +00001000- readline now supports setting the startup_hook and the
1001 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +00001002
Guido van Rossumc524d952001-10-19 01:31:59 +00001003- os and posix supports chroot(), setgroups() and unsetenv() where
1004 available. The stat(), fstat(), statvfs() and fstatvfs() functions
1005 now return "pseudo-sequences" -- the various fields can now be
1006 accessed as attributes (e.g. os.stat("/").st_mtime) but for
1007 backwards compatibility they also behave as a fixed-length sequence.
1008 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +00001009 attributes.
1010
1011- time: localtime(), gmtime() and strptime() now return a
1012 pseudo-sequence similar to the os.stat() return value, with
1013 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +00001014
Guido van Rossum9074ef62001-10-16 21:34:49 +00001015- Decompression objects in the zlib module now accept an optional
1016 second parameter to decompress() that specifies the maximum amount
1017 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +00001018
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001019- optional SSL support in the socket module now exports OpenSSL
1020 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
1021 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +00001022 automatically seed its PRNG. Also, the keyfile and certfile
1023 arguments to socket.ssl() are now optional.
1024
1025- posixmodule (and by extension, the os module on POSIX platforms) now
1026 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001027
Guido van Rossum9074ef62001-10-16 21:34:49 +00001028Library
Guido van Rossum3c288632001-10-16 21:13:49 +00001029
Tim Peters7402f792001-10-02 03:53:41 +00001030- doctest now excludes functions and classes not defined by the module
1031 being tested, thanks to Tim Hochberg.
1032
Fred Drakecb7a6b52001-10-22 18:41:51 +00001033- HotShot, a new profiler implemented using a C-based callback, has
1034 been added. This substantially reduces the overhead of profiling,
1035 but it is still quite preliminary. Support modules and
1036 documentation will be added in upcoming releases (before 2.2 final).
1037
Guido van Rossumc4b09b42001-10-04 10:19:00 +00001038- profile now produces correct output in situations where an exception
1039 raised in Python is cleared by C code (e.g. hasattr()). This used
1040 to cause wrong output, including spurious claims of recursive
1041 functions and attribution of time spent to the wrong function.
1042
Tim Peters0a1fc4e2001-10-07 03:12:08 +00001043 The code and documentation for the derived OldProfile and HotProfile
1044 profiling classes was removed. The code hasn't worked for years (if
1045 you tried to use them, they raised exceptions). OldProfile
1046 intended to reproduce the behavior of the profiler Python used more
1047 than 7 years ago, and isn't interesting anymore. HotProfile intended
1048 to provide a faster profiler (but producing less information), and
1049 that's a worthy goal we intend to meet via a different approach (but
1050 without losing information).
1051
Tim Peterscce092d2001-10-09 05:31:56 +00001052- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +00001053 a much better system-specific calibration constant. The constant can
1054 now be specified in an instance constructor, or as a Profile class or
1055 instance variable, instead of by editing profile.py's source code.
1056 Calibration must still be done manually (see the docs for the profile
1057 module).
1058
1059 Note that Profile.calibrate() must be overriden by subclasses.
1060 Improving the accuracy required exploiting detailed knowledge of
1061 profiler internals; the earlier method abstracted away the details
1062 and measured a simplified model instead, but consequently computed
1063 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +00001064
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001065- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +00001066 which indicates whether output is intended for the header 'Q'
1067 encoding.
1068
Guido van Rossuma5343cc2001-10-18 18:02:07 +00001069- The SocketServer.ThreadingMixIn class now closes the request after
1070 finish_request() returns. (Not when it errors out though.)
1071
Barry Warsawf6fb1712001-10-19 05:35:40 +00001072- The nntplib module's NNTP.body() method has grown a `file' argument
1073 to allow saving the message body to a file.
1074
1075- The email package has added a class email.Parser.HeaderParser which
1076 only parses headers and does not recurse into the message's body.
1077 Also, the module/class MIMEAudio has been added for representing
1078 audio data (contributed by Anthony Baxter).
1079
1080- ftplib should be able to handle files > 2GB.
1081
1082- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
1083 ON, and OFF.
1084
Fred Drakecb7a6b52001-10-22 18:41:51 +00001085- xml.dom.minidom NodeList objects now support the length attribute
1086 and item() method as required by the DOM specifications.
1087
Guido van Rossumed554f62001-10-02 23:15:37 +00001088Tools/Demos
1089
1090- Demo/dns was removed. It no longer serves any purpose; a package
1091 derived from it is now maintained by Anthony Baxter, see
1092 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +00001093
Barry Warsawf6fb1712001-10-19 05:35:40 +00001094- The freeze tool has been made more robust, and two new options have
1095 been added: -X and -E.
1096
Tim Petersabf925f2001-09-28 21:53:42 +00001097Build
1098
Barry Warsawf6fb1712001-10-19 05:35:40 +00001099- configure will use CXX in LINKCC if CXX is used to build main() and
1100 the system requires to link a C++ main using the C++ compiler.
1101
Tim Petersabf925f2001-09-28 21:53:42 +00001102C API
1103
Guido van Rossum6c4bce32001-10-18 19:20:25 +00001104- The documentation for the tp_compare slot is updated to require that
1105 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
1106 not correct. This is not yet enforced but will be enforced in
1107 Python 2.3; even later, we may use -2 to indicate errors and +2 for
1108 "NotImplemented". Right now, -1 should be used for an error return.
1109
Tim Petersd38b1c72001-09-30 05:09:37 +00001110- PyLong_AsLongLong() now accepts int (as well as long) arguments.
1111 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
1112 as long) arguments.
1113
Guido van Rossum3c288632001-10-16 21:13:49 +00001114- PyThread_start_new_thread() now returns a long int giving the thread
1115 ID, if one can be calculated; it returns -1 for error, 0 if no
1116 thread ID is calculated (this is an incompatible change, but only
1117 the thread module used this API). This code has only really been
1118 tested on Linux and Windows; other platforms please beware (and
1119 report any bugs or strange behavior).
1120
Guido van Rossum1c486092001-10-19 02:05:35 +00001121- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
1122 input.
1123
Tim Petersabf925f2001-09-28 21:53:42 +00001124New platforms
1125
1126Tests
1127
1128Windows
1129
Tim Peters04cf1d32001-10-09 22:39:40 +00001130- Installer: If you install IDLE, and don't disable file-extension
1131 registration, a new "Edit with IDLE" context (right-click) menu entry
1132 is created for .py and .pyw files.
1133
Tim Peters1ce3cf72001-10-01 17:58:40 +00001134- The signal module now supports SIGBREAK on Windows, thanks to Steven
1135 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
1136 action remains to call Win32 ExitProcess(). This can be changed via
1137 signal.signal(). For example:
1138
1139 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
1140 # (SIGINT) behavior.
1141 import signal
1142 signal.signal(signal.SIGBREAK,
1143 signal.default_int_handler)
1144
1145 try:
1146 while 1:
1147 pass
1148 except KeyboardInterrupt:
1149 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
1150 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
1151 # program without the possibility for any Python-level cleanup).
1152 print "Clean exit"
1153
Tim Petersabf925f2001-09-28 21:53:42 +00001154
Tim Petersb07352e2001-09-08 01:25:47 +00001155What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001156Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +00001157===========================
1158
Guido van Rossum808eea72001-09-25 04:15:41 +00001159Type/class unification and new-style classes
1160
1161- pydoc and inspect are now aware of new-style classes;
1162 e.g. help(list) at the interactive prompt now shows proper
1163 documentation for all operations on list objects.
1164
1165- Applications using Jim Fulton's ExtensionClass module can now safely
1166 be used with Python 2.2. In particular, Zope 2.4.1 now works with
1167 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
1168 examples also work again. It is hoped that Gtk and Boost also work
1169 with 2.2a4 and beyond. (If you can confirm this, please write
1170 webmaster@python.org; if there are still problems, please open a bug
1171 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +00001172
Tim Peters66c1a522001-09-24 21:17:50 +00001173- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001174 These map to read-only attributes 'fget', 'fset', 'fdel', and '__doc__'
Tim Peters66c1a522001-09-24 21:17:50 +00001175 in the constructed property object. fget, fset and fdel weren't
1176 discoverable from Python in 2.2a3. __doc__ is new, and allows to
1177 associate a docstring with a property.
1178
Guido van Rossum808eea72001-09-25 04:15:41 +00001179- Comparison overloading is now more completely implemented. For
1180 example, a str subclass instance can properly be compared to a str
1181 instance, and it can properly overload comparison. Ditto for most
1182 other built-in object types.
1183
1184- The repr() of new-style classes has changed; instead of <type
1185 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
1186 *except* for built-in types, which are still rendered as <type
1187 'Foo'> (to avoid upsetting existing code that might parse or
1188 otherwise rely on repr() of certain type objects).
1189
1190- The repr() of new-style objects is now always <Foo object at XXX>;
1191 previously, it was sometimes <Foo instance at XXX>.
1192
1193- For new-style classes, what was previously called __getattr__ is now
1194 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001195 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +00001196 one in classic classes is defined which is called only if regular
1197 attribute access raises AttributeError; to catch *all* attribute
1198 access, you can use __getattribute__ (for new-style classes). If
1199 both are defined, __getattribute__ is called first, and if it raises
1200 AttributeError, __getattr__ is called.
1201
1202- The __class__ attribute of new-style objects can be assigned to.
1203 The new class must have the same C-level object layout as the old
1204 class.
1205
1206- The builtin file type can be subclassed now. In the usual pattern,
1207 "file" is the name of the builtin type, and file() is a new builtin
1208 constructor, with the same signature as the builtin open() function.
1209 file() is now the preferred way to open a file.
1210
1211- Previously, __new__ would only see sequential arguments passed to
1212 the type in a constructor call; __init__ would see both sequential
1213 and keyword arguments. This made no sense whatsoever any more, so
1214 now both __new__ and __init__ see all arguments.
1215
1216- Previously, hash() applied to an instance of a subclass of str or
1217 unicode always returned 0. This has been repaired.
1218
1219- Previously, an operation on an instance of a subclass of an
1220 immutable type (int, long, float, complex, tuple, str, unicode),
1221 where the subtype didn't override the operation (and so the
1222 operation was handled by the builtin type), could return that
1223 instance instead a value of the base type. For example, if s was of
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001224 a str subclass type, s[:] returned s as-is. Now it returns a str
Guido van Rossum808eea72001-09-25 04:15:41 +00001225 with the same value as s.
1226
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001227- Provisional support for pickling new-style objects has been added.
1228
Guido van Rossum808eea72001-09-25 04:15:41 +00001229Core
1230
Tim Peters2c9aa5e2001-09-23 04:06:05 +00001231- file.writelines() now accepts any iterable object producing strings.
1232
Marc-André Lemburgaefd7662001-09-20 12:59:37 +00001233- PyUnicode_FromEncodedObject() now works very much like
1234 PyObject_Str(obj) in that it tries to use __str__/tp_str
1235 on the object if the object is not a string or buffer. This
1236 makes unicode() behave like str() when applied to non-string/buffer
1237 objects.
1238
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001239- PyFile_WriteObject now passes Unicode objects to the file's write
1240 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +00001241 of a print statement must support Unicode objects, i.e. they must
1242 at least convert them into ASCII strings.
1243
Guido van Rossum624c8af2001-09-18 15:21:04 +00001244- Thread scheduling on Solaris should be improved; it is no longer
1245 necessary to insert a small sleep at the start of a thread in order
1246 to let other runnable threads be scheduled.
1247
Tim Petersb07352e2001-09-08 01:25:47 +00001248Library
1249
Marc-André Lemburgbf990172001-09-27 14:17:33 +00001250- StringIO.StringIO instances and cStringIO.StringIO instances support
1251 read character buffer compatible objects for their .write() methods.
1252 These objects are converted to strings and then handled as such
1253 by the instances.
1254
Barry Warsaw2f600732001-09-24 04:28:10 +00001255- The "email" package has been added. This is basically a port of the
1256 mimelib package <http://sf.net/projects/mimelib> with API changes
1257 and some implementations updated to use iterators and generators.
1258
Tim Peters8a9c2842001-09-22 21:30:22 +00001259- difflib.ndiff() and difflib.Differ.compare() are generators now. This
1260 restores the ability of Tools/scripts/ndiff.py to start producing output
1261 before the entire comparison is complete.
1262
Barry Warsaw58b072d2001-09-22 04:44:21 +00001263- StringIO.StringIO instances and cStringIO.StringIO instances support
1264 iteration just like file objects (i.e. their .readline() method is
1265 called for each iteration until it returns an empty string).
1266
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +00001267- The codecs module has grown four new helper APIs to access
1268 builtin codecs: getencoder(), getdecoder(), getreader(),
1269 getwriter().
1270
Guido van Rossum624c8af2001-09-18 15:21:04 +00001271- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
1272 simplifies writing XML RPC servers.
1273
Barry Warsaw647d5e82001-09-28 17:01:02 +00001274- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +00001275 after interpretation of symbolic links. On non-Unix systems, this
1276 is an alias for os.path.abspath().
1277
Tim Peters16a77ad2001-09-08 04:00:12 +00001278- operator.indexOf() (PySequence_Index() in the C API) now works with any
1279 iterable object.
1280
Guido van Rossum624c8af2001-09-18 15:21:04 +00001281- smtplib now supports various authentication and security features of
1282 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001283
Guido van Rossum624c8af2001-09-18 15:21:04 +00001284- hmac: a new module implementing keyed hashing for message
1285 authentication.
1286
1287- mimetypes now recognizes more extensions and file types. At the
1288 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001289
Guido van Rossum624c8af2001-09-18 15:21:04 +00001290- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001291 Python 2.2 bytecode generation. It has also been promoted from a
1292 Tool to a standard library package. (Tools/compiler still exists as
1293 a sample driver.)
1294
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001295Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +00001296
Tim Petersb07352e2001-09-08 01:25:47 +00001297Build
1298
Guido van Rossum624c8af2001-09-18 15:21:04 +00001299- Large file support (LFS) is now automatic when the platform supports
1300 it; no more manual configuration tweaks are needed. On Linux, at
1301 least, it's possible to have a system whose C library supports large
1302 files but whose kernel doesn't; in this case, large file support is
1303 still enabled but doesn't do you any good unless you upgrade your
1304 kernel or share your Python executable with another system whose
1305 kernel has large file support.
1306
1307- The configure script now supplies plausible defaults in a
1308 cross-compilation environment. This doesn't mean that the supplied
1309 values are always correct, or that cross-compilation now works
1310 flawlessly -- but it's a first step (and it shuts up most of
1311 autoconf's warnings about AC_TRY_RUN).
1312
1313- The Unix build is now a bit less chatty, courtesy of the parser
1314 generator. The build is completely silent (except for errors) when
1315 using "make -s", thanks to a -q option to setup.py.
1316
Tim Petersb07352e2001-09-08 01:25:47 +00001317C API
1318
Guido van Rossum624c8af2001-09-18 15:21:04 +00001319- The "structmember" API now supports some new flag bits to deny read
1320 and/or write access to attributes in restricted execution mode.
1321
Tim Petersb07352e2001-09-08 01:25:47 +00001322New platforms
1323
Guido van Rossum624c8af2001-09-18 15:21:04 +00001324- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1325 (http://familiar.handhelds.org).
1326
Tim Petersb07352e2001-09-08 01:25:47 +00001327Tests
1328
Tim Peters8a9c2842001-09-22 21:30:22 +00001329- The "classic" standard tests, which work by comparing stdout to
1330 an expected-output file under Lib/test/output/, no longer stop at
1331 the first mismatch. Instead the test is run to completion, and a
1332 variant of ndiff-style comparison is used to report all differences.
1333 This is much easier to understand than the previous style of reporting.
1334
1335- The unittest-based standard tests now use regrtest's test_main()
1336 convention, instead of running as a side-effect of merely being
1337 imported. This allows these tests to be run in more natural and
1338 flexible ways as unittests, outside the regrtest framework.
1339
1340- regrtest.py is much better integrated with unittest and doctest now,
1341 especially in regard to reporting errors.
1342
Tim Petersb07352e2001-09-08 01:25:47 +00001343Windows
1344
Guido van Rossum624c8af2001-09-18 15:21:04 +00001345- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001346 that support it (NTFS under Windows 2000). See "What's New in
1347 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001348
Tim Petersb07352e2001-09-08 01:25:47 +00001349
Tim Petersedc99312001-08-22 21:36:50 +00001350What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001351Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001352===========================
1353
1354Core
1355
Tim Peters9fffa3e2001-09-04 05:14:19 +00001356- Conversion of long to float now raises OverflowError if the long is too
1357 big to represent as a C double.
1358
Tim Peters32f453e2001-09-03 08:35:41 +00001359- The 3-argument builtin pow() no longer allows a third non-None argument
1360 if either of the first two arguments is a float, or if both are of
1361 integer types and the second argument is negative (in which latter case
1362 the arguments are converted to float, so this is really the same
1363 restriction).
1364
Tim Peters5d2b77c2001-09-03 05:47:38 +00001365- The builtin dir() now returns more information, and sometimes much
1366 more, generally naming all attributes of an object, and all attributes
1367 reachable from the object via its class, and from its class's base
1368 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1369 an empty list. In 2.2a3,
1370
1371 >>> dir([])
1372 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1373 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1374 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1375 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1376 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1377 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1378 'reverse', 'sort']
1379
1380 dir(module) continues to return only the module's attributes, though.
1381
Tim Petersbdee63f2001-09-02 03:40:59 +00001382- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001383 than raising OverflowError. This is a partial implementation of PEP
1384 237. You can use -Wdefault::OverflowWarning to enable a warning for
1385 this situation, and -Werror::OverflowWarning to revert to the old
1386 OverflowError exception.
1387
Guido van Rossum61c345f2001-09-04 03:26:15 +00001388- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001389 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001390 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1391 -Qold, meaning the / operator has its classic meaning and no
1392 warnings are issued. Using -Qwarn issues a run-time warning about
1393 all uses of classic division for int and long arguments; -Qwarnall
1394 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001395 (for use with fixdiv.py).
1396 [Note: the remainder of this paragraph (preserved below) became
1397 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1398 <obsolete>
1399 Using -Qnew is questionable; it turns on new division by default, but
1400 only in the __main__ module. You can usefully combine -Qwarn or
1401 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1402 warns about classic division everywhere else.
1403 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001404
Tim Petersbdee63f2001-09-02 03:40:59 +00001405- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001406 long, float, str, unicode, and tuple. (The types complex, list and
1407 dictionary can also be subclassed; this was introduced earlier.)
1408 Note that restrictions apply when subclassing immutable built-in
1409 types: you can only affect the value of the instance by overloading
1410 __new__. You can add mutable attributes, and the subclass instances
1411 will have a __dict__ attribute, but you cannot change the "value"
1412 (as implemented by the base class) of an immutable subclass instance
1413 once it is created.
1414
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001415- The dictionary constructor now takes an optional argument, a
1416 mapping-like object, and initializes the dictionary from its
1417 (key, value) pairs.
1418
Tim Petersbdee63f2001-09-02 03:40:59 +00001419- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001420 "cooperative super calls" in a multiple inheritance setting. For an
1421 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1422
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001423- A new built-in type, property, has been added. This enables the
1424 creation of "properties". These are attributes implemented by
1425 getter and setter functions (or only one of these for read-only or
1426 write-only attributes), without the need to override __getattr__.
1427 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001428
Tim Petersbdee63f2001-09-02 03:40:59 +00001429- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001430 liberalized, to allow leading zeroes. Examples of literals now
1431 legal that were SyntaxErrors before:
1432
1433 00.0 0e3 0100j 07.5 00000000000000000008.
1434
Tim Petersbdee63f2001-09-02 03:40:59 +00001435- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001436 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1437
Tim Petersedc99312001-08-22 21:36:50 +00001438Library
1439
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001440- telnetlib includes symbolic names for the options, and support for
1441 setting an option negotiation callback.
1442
Tim Petersa40c7932001-09-05 22:36:56 +00001443- The new C standard no longer requires that math libraries set errno to
1444 ERANGE on overflow. For platform libraries that exploit this new
1445 freedom, Python's overflow-checking was wholly broken. A new overflow-
1446 checking scheme attempts to repair that, but may not be reliable on all
1447 platforms (C doesn't seem to provide anything both useful and portable
1448 in this area anymore).
1449
Martin v. Löwis44f86962001-09-05 13:44:54 +00001450- Asynchronous timeout actions are available through the new class
1451 threading.Timer.
1452
Tim Peters78526162001-09-05 00:53:45 +00001453- math.log and math.log10 now return sensible results for even huge
1454 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1455
Tim Petersbdee63f2001-09-02 03:40:59 +00001456- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001457 currently held. See the docs for the imp module.
1458
Tim Petersbdee63f2001-09-02 03:40:59 +00001459- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001460 dumps containing ints written on platforms where Python ints are 8 bytes.
1461 When read on a box where Python ints are 4 bytes, such values are
1462 converted to Python longs.
1463
Tim Petersbdee63f2001-09-02 03:40:59 +00001464- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001465 code objects is no longer allowed. This plugs a security hole.
1466
Steve Purcell6091cd62001-09-06 16:05:17 +00001467- unittest.TestResult instances no longer store references to tracebacks
1468 generated by test failures. This prevents unexpected dangling references
1469 to objects that should be garbage collected between tests.
1470
Tim Petersedc99312001-08-22 21:36:50 +00001471Tools
1472
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001473- Tools/scripts/fixdiv.py has been added which can be used to fix
1474 division operators as per PEP 238.
1475
Tim Petersedc99312001-08-22 21:36:50 +00001476Build
1477
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001478- If you are an adventurous person using Mac OS X you may want to look at
1479 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1480 application, which can be used for experimenting with Carbon or Cocoa.
1481 Discussion of this on pythonmac-sig, please.
1482
Tim Peters7eea37e2001-09-04 22:08:56 +00001483C API
1484
1485- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001486
Tim Peters9fffa3e2001-09-04 05:14:19 +00001487- Note that PyLong_AsDouble can fail! This has always been true, but no
1488 callers checked for it. It's more likely to fail now, because overflow
1489 errors are properly detected now. The proper way to check:
1490
1491 double x = PyLong_AsDouble(some_long_object);
1492 if (x == -1.0 && PyErr_Occurred()) {
1493 /* The conversion failed. */
1494 }
1495
Tim Petersbdee63f2001-09-02 03:40:59 +00001496- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001497 compile but will not participate in GC. To upgrade an extension
1498 module:
1499
1500 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001501
Neil Schemenauer4042c692001-08-30 15:38:01 +00001502 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1503 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001504
Neil Schemenauer4042c692001-08-30 15:38:01 +00001505 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1506 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001507
Neil Schemenauer4042c692001-08-30 15:38:01 +00001508 - remove PyGC_HEAD_SIZE from object size calculations
1509
1510 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1511
Tim Petersbdee63f2001-09-02 03:40:59 +00001512- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001513 These can be used safely to construct string objects from a
1514 sprintf-style format string (similar to the format string supported
1515 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001516
Tim Petersedc99312001-08-22 21:36:50 +00001517New platforms
1518
Tim Petersb7da0902001-09-02 23:01:43 +00001519- Stephen Hansen contributed patches sufficient to get a clean compile
1520 under Borland C (Windows), but he reports problems running it and ran
1521 out of time to complete the port. Volunteers? Expect a MemoryError
1522 when importing the types module; this is probably shallow, and
1523 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001524
Tim Petersedc99312001-08-22 21:36:50 +00001525Tests
1526
1527Windows
1528
Tim Peters6e13a562001-09-06 00:32:15 +00001529- Large file support is now enabled on Win32 platforms as well as on
1530 Win64. This means that, for example, you can use f.tell() and f.seek()
1531 to manipulate files larger than 2 gigabytes (provided you have enough
1532 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001533 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1534 filesize limit, and large file support makes no difference there.
1535 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1536 NTFS has no practical limit on file size, and files of any size can be
1537 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001538
Tim Petersbdee63f2001-09-02 03:40:59 +00001539- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001540 points to command.com (patch from Brian Quinlan).
1541
Tim Petersedc99312001-08-22 21:36:50 +00001542
Tim Peters20f51a72001-07-21 02:31:40 +00001543What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001544Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001545===========================
1546
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001547Build
1548
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001549- Tim Peters developed a brand new Windows installer using Wise 8.1,
1550 generously donated to us by Wise Solutions.
1551
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001552- configure supports a new option --enable-unicode, with the values
1553 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1554 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001555
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001556- A new configure option --enable-framework builds a Mac OS X framework,
1557 which "make frameworkinstall" will install. This provides a starting
1558 point for more mac-like functionality, join pythonmac-sig@python.org
1559 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001560
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001561- The NeXT platform is no longer supported.
1562
1563- The `new' module is now statically linked.
1564
Tim Peters0afb6092001-08-15 06:06:44 +00001565Tools
1566
1567- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001568 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001569 the module docstring for details.
1570
Tim Peters20f51a72001-07-21 02:31:40 +00001571Tests
1572
Tim Peters5e824c32001-08-12 22:25:01 +00001573- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001574 platforms, allowing to give clearer test result output. regrtest
1575 also has optional --use/-u switch to run normally disabled tests
1576 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001577
Tim Peters20f51a72001-07-21 02:31:40 +00001578- Several new tests in the standard test suite, with special thanks to
1579 Nick Mathewson.
1580
1581Core
1582
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001583- The floor division operator // has been added as outlined in PEP
1584 238. The / operator still provides classic division (and will until
1585 Python 3.0) unless "from __future__ import division" is included, in
1586 which case the / operator will provide true division. The operator
1587 module provides truediv() and floordiv() functions. Augmented
1588 assignment variants are included, as are the equivalent overloadable
1589 methods and C API methods. See the PEP for a full discussion:
1590 <http://python.sf.net/peps/pep-0238.html>
1591
Tim Peters6cd6a822001-08-17 22:11:27 +00001592- Future statements are now effective in simulated interactive shells
1593 (like IDLE). This should "just work" by magic, but read Michael
1594 Hudson's "Future statements in simulated shells" PEP 264 for full
1595 details: <http://python.sf.net/peps/pep-0264.html>.
1596
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001597- The type/class unification (PEP 252-253) was integrated into the
1598 trunk and is not so tentative any more (the exact specification of
1599 some features is still tentative). A lot of work has done on fixing
1600 bugs and adding robustness and features (performance still has to
1601 come a long way).
1602
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001603- Warnings about a mismatch in the Python API during extension import
1604 now use the Python warning framework (which makes it possible to
1605 write filters for these warnings).
1606
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001607- A function's __dict__ (aka func_dict) will now always be a
1608 dictionary. It used to be possible to delete it or set it to None,
1609 but now both actions raise TypeErrors. It is still legal to set it
1610 to a dictionary object. Getting func.__dict__ before any attributes
1611 have been assigned now returns an empty dictionary instead of None.
1612
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001613- A new command line option, -E, was added which disables the use of
1614 all environment variables, or at least those that are specifically
1615 significant to Python. Usually those have a name starting with
1616 "PYTHON". This was used to fix a problem where the tests fail if
1617 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1618 older distribution.
1619
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001620Library
1621
Tim Peters5e824c32001-08-12 22:25:01 +00001622- New class Differ and new functions ndiff() and restore() in difflib.py.
1623 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001624 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001625
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001626- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1627 value using the minimal quoting required for the value; more
1628 reliable than using xml.sax.saxutils.escape() for attribute values.
1629
1630- Readline completion support for cmd.Cmd was added.
1631
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001632- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1633
1634- Added function threading.BoundedSemaphore()
1635
1636- Added Ka-Ping Yee's cgitb.py module.
1637
1638- The `new' module now exposes the CO_xxx flags.
1639
Martin v. Löwis560da622001-11-24 09:24:51 +00001640- The gc module offers the get_referents function.
1641
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001642New platforms
1643
1644C API
1645
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001646- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1647 which provide a cross-platform implementations for the
1648 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1649 the standard sprintf() and vsprintf() C lib APIs, these versions
1650 apply bounds checking on the used buffer which enhances protection
1651 against buffer overruns.
1652
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001653- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001654 and extensions using different Unicode widths is rendered next to
1655 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001656 will result in an ImportError. Unicode extensions writers must make
1657 sure to check the Unicode width compatibility in their extensions by
1658 using at least one of the mangled Unicode APIs in the extension.
1659
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001660- Two new flags METH_NOARGS and METH_O are available in method definition
1661 tables to simplify implementation of methods with no arguments and a
1662 single untyped argument. Calling such methods is more efficient than
1663 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1664 deprecated.
1665
Tim Petersc1731372001-08-04 08:12:36 +00001666Windows
1667
1668- "import module" now compiles module.pyw if it exists and nothing else
1669 relevant is found.
1670
Tim Peters20f51a72001-07-21 02:31:40 +00001671
Guido van Rossum55a78992001-07-17 17:22:32 +00001672What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001673Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001674===========================
1675
1676Core
Tim Petersa814db52001-05-14 07:05:58 +00001677
Tim Peters6d6c1a32001-08-02 04:15:00 +00001678- TENTATIVELY, a large amount of code implementing much of what's
1679 described in PEP 252 (Making Types Look More Like Classes) and PEP
1680 253 (Subtyping Built-in Types) was added. This will be released
1681 with Python 2.2a1. Documentation will be provided separately
1682 through http://www.python.org/2.2/. The purpose of releasing this
1683 with Python 2.2a1 is to test backwards compatibility. It is
1684 possible, though not likely, that a decision is made not to release
1685 this code as part of 2.2 final, if any serious backwards
1686 incompapatibilities are found during alpha testing that cannot be
1687 repaired.
1688
Guido van Rossum55a78992001-07-17 17:22:32 +00001689- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001690 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001691 more 'yield' statements. See PEP 255. Since this adds a new
1692 keyword to the language, this feature must be enabled by including a
1693 future statement: "from __future__ import generators" (see PEP 236).
1694 Generators will become a standard feature in a future release
1695 (probably 2.3). Without this future statement, 'yield' remains an
1696 ordinary identifier, but a warning is issued each time it is used.
1697 (These warnings currently don't conform to the warnings framework of
1698 PEP 230; we intend to fix this in 2.2a2.)
1699
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001700- The UTF-16 codec was modified to be more RFC compliant. It will now
1701 only remove BOM characters at the start of the string and then
1702 only if running in native mode (UTF-16-LE and -BE won't remove a
1703 leading BMO character).
1704
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001705- Strings now have a new method .decode() to complement the already
1706 existing .encode() method. These two methods provide direct access
1707 to the corresponding decoders and encoders of the registered codecs.
1708
1709 To enhance the usability of the .encode() method, the special
1710 casing of Unicode object return values was dropped (Unicode objects
1711 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001712
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001713 Both methods will now return whatever the codec in charge of the
1714 requested encoding returns as object, e.g. Unicode codecs will
1715 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1716 will return u"äöü"). This enables codec writer to create codecs
1717 for various simple to use conversions.
1718
1719 New codecs were added to demonstrate these new features (the .encode()
1720 and .decode() columns indicate the type of the returned objects):
1721
1722 Name | .encode() | .decode() | Description
1723 ----------------------------------------------------------------------
1724 uu | string | string | UU codec (e.g. for email)
1725 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001726 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001727 zlib | string | string | zlib compression
1728 hex | string | string | 2-byte hex codec
1729 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1730
Mark Hammond2a0af792001-05-14 03:09:36 +00001731- Some operating systems now support the concept of a default Unicode
1732 encoding for file system operations. Notably, Windows supports 'mbcs'
1733 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001734 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001735 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001736
1737 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001738 functions that return filenames (such as os.listdir()) to return Python
1739 string objects pre-encoded using the default file system encoding for
1740 the platform. As this encoding is likely to be different from Python's
1741 default encoding, converting this name to a Unicode object before passing
1742 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001743 would attempt to use its default encoding (generally ASCII) rather than
1744 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001745
Tim Petersa814db52001-05-14 07:05:58 +00001746 In general, this change simply removes surprises when working with
1747 Unicode and the file system, making these operations work as you expect,
1748 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001749 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001750
Tim Peters61dff2b2001-05-08 15:43:37 +00001751- Float (and complex) literals in source code were evaluated to full
1752 precision only when running from a .py file; the same code loaded from a
1753 .pyc (or .pyo) file could suffer numeric differences starting at about the
1754 12th significant decimal digit. For example, on a machine with IEEE-754
1755 floating arithmetic,
1756
1757 x = 9007199254740992.0
1758 print long(x)
1759
1760 printed 9007199254740992 if run directly from .py, but 9007199254740000
1761 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1762 str(float) instead of repr(float) when building code objects. marshal
1763 now uses repr(float) instead, which should reproduce floats to full
1764 machine precision (assuming the platform C float<->string I/O conversion
1765 functions are of good quality).
1766
1767 This may cause floating-point results to change in some cases, and
1768 usually for the better, but may also cause numerically unstable
1769 algorithms to break.
1770
Tim Peters2f228e72001-05-13 00:19:31 +00001771- The implementation of dicts suffers fewer collisions, which has speed
1772 benefits. However, the order in which dict entries appear in dict.keys(),
1773 dict.values() and dict.items() may differ from previous releases for a
1774 given dict. Nothing is defined about this order, so no program should
1775 rely on it. Nevertheless, it's easy to write test cases that rely on the
1776 order by accident, typically because of printing the str() or repr() of a
1777 dict to an "expected results" file. See Lib/test/test_support.py's new
1778 sortdict(dict) function for a simple way to display a dict in sorted
1779 order.
1780
Tim Peters7a3bfc32001-06-12 01:22:22 +00001781- Many other small changes to dicts were made, resulting in faster
1782 operation along the most common code paths.
1783
Guido van Rossum10315822001-05-01 20:54:30 +00001784- Dictionary objects now support the "in" operator: "x in dict" means
1785 the same as dict.has_key(x).
1786
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001787- The update() method of dictionaries now accepts generic mapping
1788 objects. Specifically the argument object must support the .keys()
1789 and __getitem__() methods. This allows you to say, for example,
1790 {}.update(UserDict())
1791
Guido van Rossum10315822001-05-01 20:54:30 +00001792- Iterators were added; this is a generalized way of providing values
1793 to a for loop. See PEP 234. There's a new built-in function iter()
1794 to return an iterator. There's a new protocol to get the next value
1795 from an iterator using the next() method (in Python) or the
1796 tp_iternext slot (in C). There's a new protocol to get iterators
1797 using the __iter__() method (in Python) or the tp_iter slot (in C).
1798 Iterating (i.e. a for loop) over a dictionary generates its keys.
1799 Iterating over a file generates its lines.
1800
Tim Petersf553f892001-05-01 20:45:31 +00001801- The following functions were generalized to work nicely with iterator
1802 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001803 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001804 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1805 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001806 join() method of strings
1807 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001808 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1809 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001810 right-hand side of assignment statements with multiple targets, such as
1811 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001812
Tim Petersd85e1022001-05-11 21:51:48 +00001813- Accessing module attributes is significantly faster (for example,
1814 random.random or os.path or yourPythonModule.yourAttribute).
1815
Tim Peterse63415e2001-05-08 04:38:29 +00001816- Comparing dictionary objects via == and != is faster, and now works even
1817 if the keys and values don't support comparisons other than ==.
1818
Tim Peters95bf9392001-05-10 08:32:44 +00001819- Comparing dictionaries in ways other than == and != is slower: there were
1820 insecurities in the dict comparison implementation that could cause Python
1821 to crash if the element comparison routines for the dict keys and/or
1822 values mutated the dicts. Making the code bulletproof slowed it down.
1823
Tim Peterseb28ef22001-06-02 05:27:19 +00001824- Collisions in dicts are resolved via a new approach, which can help
1825 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001826 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001827 faster now. Thanks to Christian Tismer for pointing out the cause and
1828 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001829
Tim Peters52e155e2001-06-16 05:42:57 +00001830- repr() is much faster for large containers (dict, list, tuple).
1831
1832
Tim Petersa814db52001-05-14 07:05:58 +00001833Library
1834
Fred Drake960fdf92001-07-20 18:38:26 +00001835- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1836 were added to the string module. These a locale-indenpendent
1837 constants, unlike letters, lowercase, and uppercase. These are now
1838 use in appropriate locations in the standard library.
1839
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001840- The flags used in dlopen calls can now be configured using
1841 sys.setdlopenflags and queried using sys.getdlopenflags.
1842
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001843- Fredrik Lundh's xmlrpclib is now a standard library module. This
1844 provides full client-side XML-RPC support. In addition,
1845 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1846 one asyncore-based). Thanks to Eric Raymond for the documentation.
1847
Guido van Rossum643d3912001-07-05 14:46:25 +00001848- The xrange() object is simplified: it no longer supports slicing,
1849 repetition, comparisons, efficient 'in' checking, the tolist()
1850 method, or the start, stop and step attributes. See PEP 260.
1851
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001852- A new function fnmatch.filter to filter lists of file names was added.
1853
Barry Warsawffd674d2001-05-22 16:00:10 +00001854- calendar.py uses month and day names based on the current locale.
1855
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001856- strop is now *really* obsolete (this was announced before with 1.6),
1857 and issues DeprecationWarning when used (except for the four items
1858 that are still imported into string.py).
1859
Tim Petersa814db52001-05-14 07:05:58 +00001860- Cookie.py now sorts key+value pairs by key in output strings.
1861
1862- pprint.isrecursive(object) didn't correctly identify recursive objects.
1863 Now it does.
1864
Tim Peters95b3f782001-05-14 18:39:41 +00001865- pprint functions now much faster for large containers (tuple, list, dict).
1866
Tim Peters7b9542a2001-06-10 23:40:19 +00001867- New 'q' and 'Q' format codes in the struct module, corresponding to C
1868 types "long long" and "unsigned long long" (on Windows, __int64). In
1869 native mode, these can be used only when the platform C compiler supports
1870 these types (when HAVE_LONG_LONG is #define'd by the Python config
1871 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001872 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1873 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001874
Guido van Rossum83213cc2001-06-12 16:48:52 +00001875- The site module installs a new built-in function 'help' that invokes
1876 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1877 it displays a message reminding the user to use 'help()' or
1878 'help(object)'.
1879
Tim Petersa814db52001-05-14 07:05:58 +00001880Tests
1881
1882- New test_mutants.py runs dict comparisons where the key and value
1883 comparison operators mutute the dicts randomly during comparison. This
1884 rapidly causes Python to crash under earlier releases (not for the faint
1885 of heart: it can also cause Win9x to freeze or reboot!).
1886
1887- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001888 pprint.isreadable() return sensible results. Also verifies that simple
1889 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001890
Tim Peters4324aa32001-05-28 22:30:08 +00001891C API
1892
1893- Removed the unused last_is_sticky argument from the internal
1894 _PyTuple_Resize(). If this affects you, you were cheating.
1895
1896
Guido van Rossum55a78992001-07-17 17:22:32 +00001897======================================================================
1898
1899
Guido van Rossumffe13be2001-04-16 18:46:45 +00001900What's New in Python 2.1 (final)?
1901=================================
1902
1903We only changed a few things since the last release candidate, all in
1904Python library code:
1905
1906- A bug in the locale module was fixed that affected locales which
1907 define no grouping for numeric formatting.
1908
1909- A few bugs in the weakref module's implementations of weak
1910 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1911 and the test suite was updated to check for these bugs.
1912
1913- An old bug in the os.path.walk() function (introduced in Python
1914 2.0!) was fixed: a non-existent file would cause an exception
1915 instead of being ignored.
1916
1917- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1918 PyChecker.
1919
1920
Guido van Rossum5b08f132001-04-16 02:05:23 +00001921What's New in Python 2.1c2?
1922===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001923
Guido van Rossum5b08f132001-04-16 02:05:23 +00001924A flurry of small changes, and one showstopper fixed in the nick of
1925time made it necessary to release another release candidate. The list
1926here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001927
Guido van Rossum5b08f132001-04-16 02:05:23 +00001928Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001929
Guido van Rossum5b08f132001-04-16 02:05:23 +00001930- Tim discovered a nasty bug in the dictionary code, caused by
1931 PyDict_Next() calling dict_resize(), and the GC code's use of
1932 PyDict_Next() violating an assumption in dict_items(). This was
1933 fixed with considerable amounts of band-aid, but the net effect is a
1934 saner and more robust implementation.
1935
1936- Made a bunch of symbols static that were accidentally global.
1937
1938Build and Ports
1939
1940- The setup.py script didn't check for a new enough version of zlib
1941 (1.1.3 is needed). Now it does.
1942
1943- Changed "make clean" target to also remove shared libraries.
1944
1945- Added a more general warning about the SGI Irix optimizer to README.
1946
1947Library
1948
1949- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1950 omitted the slash between host and file.html.
1951
1952- The mailbox module's _Mailbox class contained a completely broken
1953 and undocumented seek() method. Ripped it out.
1954
1955- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1956 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1957
1958- Fixed a few last-minute bugs in unittest.
1959
1960Extensions
1961
1962- Reverted the patch to the OpenSSL code in socketmodule.c to support
1963 RAND_status() and the EGD, and the subsequent patch that tried to
1964 fix it for pre-0.9.5 versions; the problem with the patch is that on
1965 some systems it issues a warning whenever socket is imported, and
1966 that's unacceptable.
1967
1968Tests
1969
1970- Fixed the pickle tests to work with "import test.test_pickle".
1971
1972- Tweaked test_locale.py to actually run the test Windows.
1973
1974- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1975 not "wb" (which is not a valid mode at all).
1976
1977- Fix pstats browser crashes. Import readline if it exists to make
1978 the user interface nicer.
1979
1980- Add "import thread" to the top of test modules that import the
1981 threading module (test_asynchat and test_threadedtempfile). This
1982 prevents test failures caused by a broken threading module resulting
1983 from a previously caught failed import.
1984
1985- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1986 needed on some platforms (e.g. Solaris 8) when the tests are run
1987 twice in succession.
1988
1989- Skip rather than fail test_sunaudiodev if no audio device is found.
1990
1991
1992What's New in Python 2.1c1?
1993===========================
1994
1995This list was significantly updated when 2.1c2 was released; the 2.1c1
1996release didn't mention most changes that were actually part of 2.1c1:
1997
1998Legal
1999
2000- Copyright was assigned to the Python Software Foundation (PSF) and a
2001 PSF license (very similar to the CNRI license) was added.
2002
2003- The CNRI copyright notice was updated to include 2001.
2004
2005Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00002006
Guido van Rossumc9932722001-04-12 02:31:27 +00002007- After a public outcry, assignment to __debug__ is no longer illegal;
2008 instead, a warning is issued. It will become illegal in 2.2.
2009
Guido van Rossum5b08f132001-04-16 02:05:23 +00002010- Fixed a core dump with "%#x" % 0, and changed the semantics so that
2011 "%#x" now always prepends "0x", even if the value is zero.
2012
2013- Fixed some nits in the bytecode compiler.
2014
2015- Fixed core dumps when calling certain kinds of non-functions.
2016
2017- Fixed various core dumps caused by reference count bugs.
2018
2019Build and Ports
2020
2021- Use INSTALL_SCRIPT to install script files.
2022
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002023- New port: SCO Unixware 7, by Billy G. Allie.
2024
Guido van Rossum5b08f132001-04-16 02:05:23 +00002025- Updated RISCOS port.
2026
2027- Updated BeOS port and notes.
2028
2029- Various other porting problems resolved.
2030
2031Library
2032
2033- The TERMIOS and SOCKET modules are now truly obsolete and
2034 unnecessary. Their symbols are incorporated in the termios and
2035 socket modules.
2036
2037- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
2038 better tests for pickling.
2039
2040- threading: make Condition.wait() robust against KeyboardInterrupt.
2041
2042- zipfile: add support to zipfile to support opening an archive
2043 represented by an open file rather than a file name. Fix bug where
2044 the archive was not properly closed. Fixed a bug in this bugfix
2045 where flush() was called for a read-only file.
2046
2047- imputil: added an uninstall() method to the ImportManager.
2048
2049- Canvas: fixed bugs in lower() and tkraise() methods.
2050
2051- SocketServer: API change (added overridable close_request() method)
2052 so that the TCP server can explicitly close the request.
2053
2054- pstats: Eric Raymond added a simple interactive statistics browser,
2055 invoked when the module is run as a script.
2056
2057- locale: fixed a problem in format().
2058
2059- webbrowser: made it work when the BROWSER environment variable has a
2060 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
2061 KDE 2. Fixed some other nits.
2062
2063- unittest: changes to allow using a different exception than
2064 AssertionError, and added a few more function aliases. Some other
2065 small changes.
2066
2067- urllib, urllib2: fixed redirect problems and a coupleof other nits.
2068
2069- asynchat: fixed a critical bug in asynchat that slipped through the
2070 2.1b2 release. Fixed another rare bug.
2071
2072- Fix some unqualified except: clauses (always a bad code example).
2073
2074XML
2075
2076- pyexpat: new API get_version_string().
2077
2078- Fixed some minidom bugs.
2079
2080Extensions
2081
2082- Fixed a core dump in _weakref. Removed the weakref.mapping()
2083 function (it adds nothing to the API).
2084
2085- Rationalized the use of header files in the readline module, to make
2086 it compile (albeit with some warnings) with the very recent readline
2087 4.2, without breaking for earlier versions.
2088
2089- Hopefully fixed a buffering problem in linuxaudiodev.
2090
2091- Attempted a fix to make the OpenSSL support in the socket module
2092 work again with pre-0.9.5 versions of OpenSSL.
2093
2094Tests
2095
2096- Added a test case for asynchat and asyncore.
2097
2098- Removed coupling between tests where one test failing could break
2099 another.
2100
2101Tools
2102
2103- Ping added an interactive help browser to pydoc, fixed some nits
2104 in the rest of the pydoc code, and added some features to his
2105 inspect module.
2106
2107- An updated python-mode.el version 4.1 which integrates Ken
2108 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
2109 much nicer in XEmacs and Emacs. When stepping through your program
2110 with pdb, in either the shell window or the *Python* window, the
2111 source file and line will be tracked by an arrow. Very cool!
2112
2113- IDLE: syntax warnings in interactive mode are changed into errors.
2114
2115- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00002116 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00002117
2118- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002119
Barry Warsaw11e89c72001-04-11 20:37:57 +00002120
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002121What's New in Python 2.1 beta 2?
2122================================
2123
Guido van Rossum053ae352001-03-22 14:17:21 +00002124(Unlisted are many fixed bugs, more documentation, etc.)
2125
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002126Core language, builtins, and interpreter
2127
Guido van Rossum053ae352001-03-22 14:17:21 +00002128- The nested scopes work (enabled by "from __future__ import
2129 nested_scopes") is completed; in particular, the future now extends
2130 into code executed through exec, eval() and execfile(), and into the
2131 interactive interpreter.
2132
2133- When calling a base class method (e.g. BaseClass.__init__(self)),
2134 this is now allowed even if self is not strictly spoken a class
2135 instance (e.g. when using metaclasses or the Don Beaudry hook).
2136
2137- Slice objects are now comparable but not hashable; this prevents
2138 dict[:] from being accepted but meaningless.
2139
2140- Complex division is now calculated using less braindead algorithms.
2141 This doesn't change semantics except it's more likely to give useful
2142 results in extreme cases. Complex repr() now uses full precision
2143 like float repr().
2144
2145- sgmllib.py now calls handle_decl() for simple <!...> declarations.
2146
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002147- It is illegal to assign to the name __debug__, which is set when the
2148 interpreter starts. It is effectively a compile-time constant.
2149
2150- A warning will be issued if a global statement for a variable
2151 follows a use or assignment of that variable.
2152
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002153Standard library
2154
Guido van Rossum053ae352001-03-22 14:17:21 +00002155- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
2156 inspired by JUnit), is now part of the standard library. You now
2157 have a choice of two testing frameworks: unittest requires you to
2158 write testcases as separate code, doctest gathers them from
2159 docstrings. Both approaches have their advantages and
2160 disadvantages.
2161
2162- A new module Tix was added, which wraps the Tix extension library
2163 for Tk. With that module, it is not necessary to statically link
2164 Tix with _tkinter, since Tix will be loaded with Tcl's "package
2165 require" command. See Demo/tix/.
2166
2167- tzparse.py is now obsolete.
2168
2169- In gzip.py, the seek() and tell() methods are removed -- they were
2170 non-functional anyway, and it's better if callers can test for their
2171 existence with hasattr().
2172
2173Python/C API
2174
2175- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
2176 that's already in the dictionary during a PyDict_Next() iteration.
2177 This used to fail occasionally when a dictionary resize operation
2178 could be triggered that would rehash all the keys. All other
2179 modifications to the dictionary are still off-limits during a
2180 PyDict_Next() iteration!
2181
2182- New extended APIs related to passing compiler variables around.
2183
2184- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
2185 implement isinstance() and issubclass().
2186
2187- Py_BuildValue() now has a "D" conversion to create a Python complex
2188 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002189
Fred Drake4e262a92001-03-22 18:26:47 +00002190- Extensions types which support weak references must now set the
2191 field allocated for the weak reference machinery to NULL themselves;
2192 this is done to avoid the cost of checking each object for having a
2193 weakly referencable type in PyObject_INIT(), since most types are
2194 not weakly referencable.
2195
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002196- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
2197 free variables and cell variables to and from the frame's f_locals.
2198
2199- Variants of several functions defined in pythonrun.h have been added
2200 to support the nested_scopes future statement. The variants all end
2201 in Flags and take an extra argument, a PyCompilerFlags *; examples:
2202 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
2203 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00002204 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002205
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002206Distutils
2207
2208- the sdist command now writes a PKG-INFO file, as described in PEP 241,
2209 into the release tree.
2210
Tim Peters0e57abf2001-05-02 07:39:38 +00002211- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002212 (an uninstaller, more customization of the installer's display)
2213
2214- from Jack Jansen: added Mac-specific code to generate a dialog for
2215 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00002216 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002217 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00002218
2219- added 'platforms' and 'keywords' to the set of metadata that can be
2220 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002221
2222- applied patches from Jason Tishler to make the compiler class work with
2223 Cygwin.
2224
2225
Tim Peters2fe289a2001-03-01 22:19:38 +00002226What's New in Python 2.1 beta 1?
2227================================
Tim Petersd66595f2001-02-04 03:09:53 +00002228
2229Core language, builtins, and interpreter
2230
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00002231- Following an outcry from the community about the amount of code
2232 broken by the nested scopes feature introduced in 2.1a2, we decided
2233 to make this feature optional, and to wait until Python 2.2 (or at
2234 least 6 months) to make it standard. The option can be enabled on a
2235 per-module basis by adding "from __future__ import nested_scopes" at
2236 the beginning of a module (before any other statements, but after
2237 comments and an optional docstring). See PEP 236 (Back to the
2238 __future__) for a description of the __future__ statement. PEP 227
2239 (Statically Nested Scopes) has been updated to reflect this change,
2240 and to clarify the semantics in a number of endcases.
2241
2242- The nested scopes code, when enabled, has been hardened, and most
2243 bugs and memory leaks in it have been fixed.
2244
2245- Compile-time warnings are now generated for a number of conditions
2246 that will break or change in meaning when nested scopes are enabled:
2247
2248 - Using "from...import *" or "exec" without in-clause in a function
2249 scope that also defines a lambda or nested function with one or
2250 more free (non-local) variables. The presence of the import* or
2251 bare exec makes it impossible for the compiler to determine the
2252 exact set of local variables in the outer scope, which makes it
2253 impossible to determine the bindings for free variables in the
2254 inner scope. To avoid the warning about import *, change it into
2255 an import of explicitly name object, or move the import* statement
2256 to the global scope; to avoid the warning about bare exec, use
2257 exec...in... (a good idea anyway -- there's a possibility that
2258 bare exec will be deprecated in the future).
2259
2260 - Use of a global variable in a nested scope with the same name as a
2261 local variable in a surrounding scope. This will change in
2262 meaning with nested scopes: the name in the inner scope will
2263 reference the variable in the outer scope rather than the global
2264 of the same name. To avoid the warning, either rename the outer
2265 variable, or use a global statement in the inner function.
2266
Neil Schemenauera35c6882001-02-27 04:45:05 +00002267- An optional object allocator has been included. This allocator is
2268 optimized for Python objects and should be faster and use less memory
2269 than the standard system allocator. It is not enabled by default
2270 because of possible thread safety problems. The allocator is only
2271 protected by the Python interpreter lock and it is possible that some
2272 extension modules require a thread safe allocator. The object
2273 allocator can be enabled by providing the "--with-pymalloc" option to
2274 configure.
2275
Tim Petersd66595f2001-02-04 03:09:53 +00002276Standard library
2277
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002278- pyexpat now detects the expat version if expat.h defines it. A
2279 number of additional handlers are provided, which are only available
2280 since expat 1.95. In addition, the methods SetParamEntityParsing and
2281 GetInputContext of Parser objects are available with 1.95.x
2282 only. Parser objects now provide the ordered_attributes and
2283 specified_attributes attributes. A new module expat.model was added,
2284 which offers a number of additional constants if 1.95.x is used.
2285
2286- xml.dom offers the new functions registerDOMImplementation and
2287 getDOMImplementation.
2288
2289- xml.dom.minidom offers a toprettyxml method. A number of DOM
2290 conformance issues have been resolved. In particular, Element now
2291 has an hasAttributes method, and the handling of namespaces was
2292 improved.
2293
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002294- Ka-Ping Yee contributed two new modules: inspect.py, a module for
2295 getting information about live Python code, and pydoc.py, a module
2296 for interactively converting docstrings to HTML or text.
2297 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002298 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002299 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2300 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002301
Tim Peters1eff7962001-03-01 02:31:33 +00002302- New library module difflib.py, primarily packaging the SequenceMatcher
2303 class at the heart of the popular ndiff.py file-comparison tool.
2304
2305- doctest.py (a framework for verifying Python code examples in docstrings)
2306 is now part of the std library.
2307
Tim Petersd66595f2001-02-04 03:09:53 +00002308Windows changes
2309
Guido van Rossume3955a82001-03-02 14:05:59 +00002310- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2311 small GUI that lets you browse the module docstrings using your
2312 default web browser.
2313
Tim Peters1eff7962001-03-01 02:31:33 +00002314- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2315 Platforms) is implemented. See
2316
2317 http://python.sourceforge.net/peps/pep-0235.html
2318
2319 for full details, especially the "Current Lower-Left Semantics" section.
2320 The new Windows import rules are simpler than before:
2321
2322 A. If the PYTHONCASEOK environment variable exists, same as
2323 before: silently accept the first case-insensitive match of any
2324 kind; raise ImportError if none found.
2325
2326 B. Else search sys.path for the first case-sensitive match; raise
2327 ImportError if none found.
2328
2329 The same rules have been implented on other platforms with case-
2330 insensitive but case-preserving filesystems too (including Cygwin, and
2331 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002332
Tim Peters25a9ce32001-02-19 07:06:36 +00002333- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2334 what it's supposed to do (and does do under NT and 2000) via direct
2335 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002336 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002337 all Win9x systems before.
2338
Tim Peters1eff7962001-03-01 02:31:33 +00002339- Build: Subproject _test (effectively) renamed to _testcapi.
2340
Tim Peters2fe289a2001-03-01 22:19:38 +00002341New platforms
2342
2343- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2344 Thanks to Steven Majewski!
2345
2346- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2347 Tishler!
2348
Guido van Rossum9089b272001-03-02 06:49:50 +00002349- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2350 Schwertberger! See RISCOS/README for more information -- it seems
2351 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002352 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002353
Tim Peters25a9ce32001-02-19 07:06:36 +00002354
Tim Petersd7b5e882001-01-25 03:36:26 +00002355What's New in Python 2.1 alpha 2?
2356=================================
Tim Peters40ead762001-01-27 05:35:26 +00002357
Tim Petersd7b5e882001-01-25 03:36:26 +00002358Core language, builtins, and interpreter
2359
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002360- Scopes nest. If a name is used in a function or class, but is not
2361 local, the definition in the nearest enclosing function scope will
2362 be used. One consequence of this change is that lambda statements
2363 could reference variables in the namespaces where the lambda is
2364 defined. In some unusual cases, this change will break code.
2365
2366 In all previous version of Python, names were resolved in exactly
2367 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002368 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002369 function A is defined within a function B, the names bound in B are
2370 not visible in A. The new rules make names bound in B visible in A,
2371 unless A contains a name binding that hides the binding in B.
2372
2373 Section 4.1 of the reference manual describes the new scoping rules
2374 in detail. The test script in Lib/test/test_scope.py demonstrates
2375 some of the effects of the change.
2376
2377 The new rules will cause existing code to break if it defines nested
2378 functions where an outer function has local variables with the same
2379 name as globals or builtins used by the inner function. Example:
2380
2381 def munge(str):
2382 def helper(x):
2383 return str(x)
2384 if type(str) != type(''):
2385 str = helper(str)
2386 return str.strip()
2387
2388 Under the old rules, the name str in helper() is bound to the
2389 builtin function str(). Under the new rules, it will be bound to
2390 the argument named str and an error will occur when helper() is
2391 called.
2392
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002393- The compiler will report a SyntaxError if "from ... import *" occurs
2394 in a function or class scope. The language reference has documented
2395 that this case is illegal, but the compiler never checked for it.
2396 The recent introduction of nested scope makes the meaning of this
2397 form of name binding ambiguous. In a future release, the compiler
2398 may allow this form when there is no possibility of ambiguity.
2399
Tim Peters40ead762001-01-27 05:35:26 +00002400- repr(string) is easier to read, now using hex escapes instead of octal,
2401 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2402
2403 >>> "\texample \r\n" + chr(0) + chr(255)
2404 '\texample \r\n\x00\xff' # in 2.1
2405 '\011example \015\012\000\377' # in 2.0
2406
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002407- Functions are now compared and hashed by identity, not by value, since
2408 the func_code attribute is writable.
2409
Fred Drakefb9d7122001-02-01 20:00:40 +00002410- Weak references (PEP 205) have been added. This involves a few
2411 changes in the core, an extension module (_weakref), and a Python
2412 module (weakref). The weakref module is the public interface. It
2413 includes support for "explicit" weak references, proxy objects, and
2414 mappings with weakly held values.
2415
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002416- A 'continue' statement can now appear in a try block within the body
2417 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002418 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002419
Tim Petersd7b5e882001-01-25 03:36:26 +00002420Standard library
2421
Barry Warsaw30dbd142001-01-31 22:14:01 +00002422- mailbox.py now has a new class, PortableUnixMailbox which is
2423 identical to UnixMailbox but uses a more portable scheme for
2424 determining From_ separators. Also, the constructors for all the
2425 classes in this module have a new optional `factory' argument, which
2426 is a callable used when new message classes must be instantiated by
2427 the next() method.
2428
Tim Petersd7b5e882001-01-25 03:36:26 +00002429- random.py is now self-contained, and offers all the functionality of
2430 the now-deprecated whrandom.py. See the docs for details. random.py
2431 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002432 and restoring the internal state of the generator; and jumpahead(n),
2433 for quickly forcing the internal state to be the same as if n calls to
2434 random() had been made. The latter is particularly useful for multi-
2435 threaded programs, creating one instance of the random.Random() class for
2436 each thread, then using .jumpahead() to force each instance to use a
2437 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002438
Tim Peters0de88fc2001-02-01 04:59:18 +00002439- random.py's seed() function is new. For bit-for-bit compatibility with
2440 prior releases, use the whseed function instead. The new seed function
2441 addresses two problems: (1) The old function couldn't produce more than
2442 about 2**24 distinct internal states; the new one about 2**45 (the best
2443 that can be done in the Wichmann-Hill generator). (2) The old function
2444 sometimes produced identical internal states when passed distinct
2445 integers, and there was no simple way to predict when that would happen;
2446 the new one guarantees to produce distinct internal states for all
2447 arguments in [0, 27814431486576L).
2448
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002449- The socket module now supports raw packets on Linux. The socket
2450 family is AF_PACKET.
2451
Tim Peters9ea17ac2001-02-02 05:57:15 +00002452- test_capi.py is a start at running tests of the Python C API. The tests
2453 are implemented by the new Modules/_testmodule.c.
2454
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002455- A new extension module, _symtable, provides provisional access to the
2456 internal symbol table used by the Python compiler. A higher-level
2457 interface will be added on top of _symtable in a future release.
2458
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002459- Removed the obsolete soundex module.
2460
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002461- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2462 the isSameNode method; NamedNodeMap the get method.
2463
2464- xml.sax.expatreader supports the lexical handler property; it
2465 generates comment, startCDATA, and endCDATA events.
2466
Tim Petersee826f82001-01-31 19:39:44 +00002467Windows changes
2468
2469- Build procedure: the zlib project is built in a different way that
2470 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002471 the zlib binary used. See PCbuild\readme.txt for details. Your old
2472 zlib-related directories can be deleted; you'll need to download fresh
2473 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002474
Tim Peters9ea17ac2001-02-02 05:57:15 +00002475- Build: New subproject _test for the benefit of test_capi.py (see above).
2476
Tim Petersb16c56f2001-02-02 21:24:51 +00002477- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2478 interface to some Python compiler internals).
2479
2480- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002481 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002482
Tim Petersa3a3a032000-11-30 05:22:44 +00002483What's New in Python 2.1 alpha 1?
2484=================================
2485
2486Core language, builtins, and interpreter
2487
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002488- There is a new Unicode companion to the PyObject_Str() API
2489 called PyObject_Unicode(). It behaves in the same way as the
2490 former, but assures that the returned value is an Unicode object
2491 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002492
Guido van Rossumf98eda02001-01-17 15:54:45 +00002493- The comparison operators support "rich comparison overloading" (PEP
2494 207). C extension types can provide a rich comparison function in
2495 the new tp_richcompare slot in the type object. The cmp() function
2496 and the C function PyObject_Compare() first try the new rich
2497 comparison operators before trying the old 3-way comparison. There
2498 is also a new C API PyObject_RichCompare() (which also falls back on
2499 the old 3-way comparison, but does not constrain the outcome of the
2500 rich comparison to a Boolean result).
2501
2502 The rich comparison function takes two objects (at least one of
2503 which is guaranteed to have the type that provided the function) and
2504 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2505 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2506 object, which may be NotImplemented (in which case the tp_compare
2507 slot function is used as a fallback, if defined).
2508
2509 Classes can overload individual comparison operators by defining one
2510 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002511 __ge__. There are no explicit "reflected argument" versions of
2512 these; instead, __lt__ and __gt__ are each other's reflection,
2513 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2514 reflection (similar at the C level). No other implications are
2515 made; in particular, Python does not assume that == is the Boolean
2516 inverse of !=, or that < is the Boolean inverse of >=. This makes
2517 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002518
2519 Classes or types that want to implement (in)equality tests but not
2520 the ordering operators (i.e. unordered types) should implement ==
2521 and !=, and raise an error for the ordering operators.
2522
Guido van Rossuma88479f2001-01-18 14:28:08 +00002523 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002524 Boolean; e.g. a matrix type might want to return a matrix of bits
2525 for A < B, giving elementwise comparisons. Such types should ensure
2526 that any interpretation of their value in a Boolean context raises
2527 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2528 at the C level) to always raise an exception.
2529
Guido van Rossuma88479f2001-01-18 14:28:08 +00002530- Complex numbers use rich comparisons to define == and != but raise
2531 an exception for <, <=, > and >=. Unfortunately, this also means
2532 that cmp() of two complex numbers raises an exception when the two
2533 numbers differ. Since it is not mathematically meaningful to compare
2534 complex numbers except for equality, I hope that this doesn't break
2535 too much code.
2536
Tim Peters3389f192001-02-18 08:48:49 +00002537- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002538 not defined by the language, other than that it's arbitrary but
2539 consistent (see the Reference Manual). An implementation detail changed
2540 in 2.1a1 such that None now compares less than any other object. Code
2541 relying on this new behavior (like code that relied on the previous
2542 behavior) does so at its own risk.
2543
Barry Warsaw573b5412001-01-15 20:43:18 +00002544- Functions and methods now support getting and setting arbitrarily
2545 named attributes (PEP 232). Functions have a new __dict__
2546 (a.k.a. func_dict) which hold the function attributes. Methods get
2547 and set attributes on their underlying im_func. It is a TypeError
2548 to set an attribute on a bound method.
2549
Guido van Rossum051e3352001-01-15 19:11:10 +00002550- The xrange() object implementation has been improved so that
2551 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2552 limitation that in this case len(xrange(sys.maxint)) can't be
2553 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2554 work fine as long as the index i doesn't actually reach 2**31.
2555 (Python uses regular ints for sequence and string indices; fixing
2556 that is much more work.)
2557
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002558- Two changes to from...import:
2559
Guido van Rossumba381232001-02-03 15:06:40 +00002560 1) "from M import X" now works even if (after loading module M)
2561 sys.modules['M'] is not a real module; it's basically a getattr()
2562 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002563
2564 2) "from M import *" now looks for M.__all__ to decide which names to
2565 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2566 filters out names starting with '_' as before. Whether or not
2567 __all__ exists, there's no restriction on the type of M.
2568
Guido van Rossumf61f1662001-01-10 20:13:55 +00002569- File objects have a new method, xreadlines(). This is the fastest
2570 way to iterate over all lines in a file:
2571
2572 for line in file.xreadlines():
2573 ...do something to line...
2574
2575 See the xreadlines module (mentioned below) for how to do this for
2576 other file-like objects.
2577
2578- Even if you don't use file.xreadlines(), you may expect a speedup on
2579 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002580 quite a bit in platform-specific ways: on systems (like Linux) that
2581 support flockfile(), getc_unlocked(), and funlockfile(), those are
2582 used by default. On systems (like Windows) without getc_unlocked(),
2583 a complicated (but still thread-safe) method using fgets() is used by
2584 default.
2585
Tim Petersd52269b2001-01-25 06:23:18 +00002586 You can force use of the fgets() method by #define'ing
2587 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002588 getc_unlocked()).
2589
Tim Petersd52269b2001-01-25 06:23:18 +00002590 You can force fgets() not to be used by #define'ing
2591 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002592 test_bufio.py fails -- and let us know if it does!).
2593
2594- In addition, the fileinput module, while still slower than the other
2595 methods on most platforms, has been sped up too, by using
2596 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002597
2598- Support for run-time warnings has been added, including a new
2599 command line option (-W) to specify the disposition of warnings.
2600 See the description of the warnings module below.
2601
2602- Extensive changes have been made to the coercion code. This mostly
2603 affects extension modules (which can now implement mixed-type
2604 numerical operators without having to use coercion), but
2605 occasionally, in boundary cases the coercion semantics have changed
2606 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002607 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002608 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002609 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002610
Guido van Rossumf98eda02001-01-17 15:54:45 +00002611- In connection with the coercion changes, a new built-in singleton
2612 object, NotImplemented is defined. This can be returned for
2613 operations that wish to indicate they are not implemented for a
2614 particular combination of arguments. From C, this is
2615 Py_NotImplemented.
2616
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002617- The interpreter accepts now bytecode files on the command line even
2618 if they do not have a .pyc or .pyo extension. On Linux, after executing
2619
Martin v. Löwise214baa2001-02-04 22:37:56 +00002620import imp,sys,string
2621magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2622reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2623open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002624
2625 any byte code file can be used as an executable (i.e. as an argument
2626 to execve(2)).
2627
Tim Peters9940b802000-12-01 07:59:35 +00002628- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002629 character. In 1.6 and earlier, they never produced a sign,
2630 and raised an error if the value of the long was too large
2631 to fit in a Python int. In 2.0, they produced a sign if and
2632 only if too large to fit in an int. This was inconsistent
2633 across platforms (because the size of an int varies across
2634 platforms), and inconsistent with hex() and oct(). Example:
2635
2636 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002637 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002638 'ffffffbe' # in 2.0 and before, on 32-bit machines
2639 >>> hex(-0x42L)
2640 '-0x42L' # in all versions of Python
2641
Tim Peters9940b802000-12-01 07:59:35 +00002642 The behavior of %d formats for negative Python longs remains
2643 the same as in 2.0 (although in 1.6 and before, they raised
2644 an error if the long didn't fit in a Python int).
2645
2646 %u formats don't make sense for Python longs, but are allowed
2647 and treated the same as %d in 2.1. In 2.0, a negative long
2648 formatted via %u produced a sign if and only if too large to
2649 fit in an int. In 1.6 and earlier, a negative long formatted
2650 via %u raised an error if it was too big to fit in an int.
2651
Guido van Rossum3661d392000-12-12 22:10:31 +00002652- Dictionary objects have an odd new method, popitem(). This removes
2653 an arbitrary item from the dictionary and returns it (in the form of
2654 a (key, value) pair). This can be useful for algorithms that use a
2655 dictionary as a bag of "to do" items and repeatedly need to pick one
2656 item. Such algorithms normally end up running in quadratic time;
2657 using popitem() they can usually be made to run in linear time.
2658
Tim Peters36cdad12000-12-29 02:06:45 +00002659Standard library
2660
Thomas Woutersfe385252001-01-19 23:16:56 +00002661- In the time module, the time argument to the functions strftime,
2662 localtime, gmtime, asctime and ctime is now optional, defaulting to
2663 the current time (in the local timezone).
2664
Guido van Rossumda91f222001-01-15 16:36:08 +00002665- The ftplib module now defaults to passive mode, which is deemed a
2666 more useful default given that clients are often inside firewalls
2667 these days. Note that this could break if ftplib is used to connect
2668 to a *server* that is inside a firewall, from outside; this is
2669 expected to be a very rare situation. To fix that, you can call
2670 ftp.set_pasv(0).
2671
Martin v. Löwis10a27872001-01-13 09:54:41 +00002672- The module site now treats .pth files not only for path configuration,
2673 but also supports extensions to the initialization code: Lines starting
2674 with import are executed.
2675
Guido van Rossumf61f1662001-01-10 20:13:55 +00002676- There's a new module, warnings, which implements a mechanism for
2677 issuing and filtering warnings. There are some new built-in
2678 exceptions that serve as warning categories, and a new command line
2679 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2680 turns warnings into errors). warnings.warn(message[, category])
2681 issues a warning message; this can also be called from C as
2682 PyErr_Warn(category, message).
2683
2684- A new module xreadlines was added. This exports a single factory
2685 function, xreadlines(). The intention is that this code is the
2686 absolutely fastest way to iterate over all lines in an open
2687 file(-like) object:
2688
2689 import xreadlines
2690 for line in xreadlines.xreadlines(file):
2691 ...do something to line...
2692
2693 This is equivalent to the previous the speed record holder using
2694 file.readlines(sizehint). Note that if file is a real file object
2695 (as opposed to a file-like object), this is equivalent:
2696
2697 for line in file.xreadlines():
2698 ...do something to line...
2699
Tim Peters36cdad12000-12-29 02:06:45 +00002700- The bisect module has new functions bisect_left, insort_left,
2701 bisect_right and insort_right. The old names bisect and insort
2702 are now aliases for bisect_right and insort_right. XXX_right
2703 and XXX_left methods differ in what happens when the new element
2704 compares equal to one or more elements already in the list: the
2705 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002706 right. Code that doesn't care where equal elements end up should
2707 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002708
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002709- The new curses.panel module wraps the panel library that forms part
2710 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2711
Guido van Rossumf61f1662001-01-10 20:13:55 +00002712- The SocketServer module now sets the allow_reuse_address flag by
2713 default in the TCPServer class.
2714
2715- A new function, sys._getframe(), returns the stack frame pointer of
2716 the caller. This is intended only as a building block for
2717 higher-level mechanisms such as string interpolation.
2718
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002719- The pyexpat module supports a number of new handlers, which are
2720 available only in expat 1.2. If invocation of a callback fails, it
2721 will report an additional frame in the traceback. Parser objects
2722 participate now in garbage collection. If expat reports an unknown
2723 encoding, pyexpat will try to use a Python codec; that works only
2724 for single-byte charsets. The parser type objects is exposed as
2725 XMLParserObject.
2726
2727- xml.dom now offers standard definitions for symbolic node type and
2728 exception code constants, and a hierarchy of DOM exceptions. minidom
2729 was adjusted to use them.
2730
2731- The conformance of xml.dom.minidom to the DOM specification was
2732 improved. It detects a number of additional error cases; the
2733 previous/next relationship works even when the tree is modified;
2734 Node supports the normalize() method; NamedNodeMap, DocumentType and
2735 DOMImplementation classes were added; Element supports the
2736 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2737 method.
2738
Guido van Rossumf61f1662001-01-10 20:13:55 +00002739Build issues
2740
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002741- For Unix (and Unix-compatible) builds, configuration and building of
2742 extension modules is now greatly automated. Rather than having to
2743 edit the Modules/Setup file to indicate which modules should be
2744 built and where their include files and libraries are, a
2745 distutils-based setup.py script now takes care of building most
2746 extension modules. All extension modules built this way are built
2747 as shared libraries. Only a few modules that must be linked
2748 statically are still listed in the Setup file; you won't need to
2749 edit their configuration.
2750
2751- Python should now build out of the box on Cygwin. If it doesn't,
2752 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002753
2754- Python now always uses its own (renamed) implementation of getopt()
2755 -- there's too much variation among C library getopt()
2756 implementations.
2757
2758- C++ compilers are better supported; the CXX macro is always set to a
2759 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002760
Tim Petersd92dfe02000-12-12 01:18:41 +00002761Windows changes
2762
2763- select module: By default under Windows, a select() call
2764 can specify no more than 64 sockets. Python now boosts
2765 this Microsoft default to 512. If you need even more than
2766 that, see the MS docs (you'll need to #define FD_SETSIZE
2767 and recompile Python from source).
2768
Guido van Rossumf61f1662001-01-10 20:13:55 +00002769- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2770 subdirectory is no more!
2771
Tim Petersa3a3a032000-11-30 05:22:44 +00002772
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002773What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002774=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002775
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002776Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002777changes are in the file HISTORY. If you are making the jump directly
2778from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2779HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002780
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002781Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2782the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2783http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002784
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002785--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002786
2787======================================================================
2788
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002789What's new in 2.0 (since release candidate 1)?
2790==============================================
2791
2792Standard library
2793
2794- The copy_reg module was modified to clarify its intended use: to
2795 register pickle support for extension types, not for classes.
2796 pickle() will raise a TypeError if it is passed a class.
2797
2798- Fixed a bug in gettext's "normalize and expand" code that prevented
2799 it from finding an existing .mo file.
2800
2801- Restored support for HTTP/0.9 servers in httplib.
2802
Tim Peters989b7b92000-10-16 20:24:53 +00002803- The math module was changed to stop raising OverflowError in case of
2804 underflow, and return 0 instead in underflow cases. Whether Python
2805 used to raise OverflowError in case of underflow was platform-
2806 dependent (it did when the platform math library set errno to ERANGE
2807 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002808
2809- Fixed a bug in StringIO that occurred when the file position was not
2810 at the end of the file and write() was called with enough data to
2811 extend past the end of the file.
2812
2813- Fixed a bug that caused Tkinter error messages to get lost on
2814 Windows. The bug was fixed by replacing direct use of
2815 interp->result with Tcl_GetStringResult(interp).
2816
2817- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2818 redirect response.
2819
2820- Several changes were made to distutils: Some debugging code was
2821 removed from util. Fixed the installer used when an external zip
2822 program (like WinZip) is not found; the source code for this
2823 installer is in Misc/distutils. check_lib() was modified to behave
2824 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2825 test for whether installed modules are on sys.path was changed to
2826 use both normcase() and normpath().
2827
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002828- Several minor bugs were fixed in the xml package (the minidom,
2829 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002830
2831- The regression test driver (regrtest.py) behavior when invoked with
2832 -l changed: It now reports a count of objects that are recognized as
2833 garbage but not freed by the garbage collector.
2834
Tim Peters989b7b92000-10-16 20:24:53 +00002835- The regression test for the math module was changed to test
2836 exceptional behavior when the test is run in verbose mode. Python
2837 cannot yet guarantee consistent exception behavior across platforms,
2838 so the exception part of test_math is run only in verbose mode, and
2839 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002840
2841Internals
2842
2843- PyOS_CheckStack() has been disabled on Win64, where it caused
2844 test_sre to fail.
2845
2846Build issues
2847
2848- Changed compiler flags, so that gcc is always invoked with -Wall and
2849 -Wstrict-prototypes. Users compiling Python with GCC should see
2850 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002851 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002852 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002853
Tim Petersa3a3a032000-11-30 05:22:44 +00002854- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002855
2856Tools and other miscellany
2857
2858- The compiler in Tools/compiler was updated to support the new
2859 language features introduced in 2.0: extended print statement, list
2860 comprehensions, and augmented assignments. The new compiler should
2861 also be backwards compatible with Python 1.5.2; the compiler will
2862 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002863 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002864
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002865What's new in 2.0 release candidate 1 (since beta 2)?
2866=====================================================
2867
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002868What is release candidate 1?
2869
2870We believe that release candidate 1 will fix all known bugs that we
2871intend to fix for the 2.0 final release. This release should be a bit
2872more stable than the previous betas. We would like to see even more
2873widespread testing before the final release, so we are producing this
2874release candidate. The final release will be exactly the same unless
2875any show-stopping (or brown bag) bugs are found by testers of the
2876release candidate.
2877
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002878All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002879to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002880
2881Core language, builtins, and interpreter
2882
2883- A bug that caused crashes when __coerce__ was used with augmented
2884 assignment, e.g. +=, was fixed.
2885
2886- Raise ZeroDivisionError when raising zero to a negative number,
2887 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2888 power operator and the result of math.pow(0.0, -2.0) will vary by
2889 platform. On Linux, it raises a ValueError.
2890
2891- A bug in Unicode string interpolation was fixed that occasionally
2892 caused errors with formats including "%%". For example, the
2893 following expression "%% %s" % u"abc" no longer raises a TypeError.
2894
2895- Compilation of deeply nested expressions raises MemoryError instead
2896 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2897
2898- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2899 rendering them useless. They are now written in binary mode again.
2900
2901Standard library
2902
2903- Keyword arguments are now accepted for most pattern and match object
2904 methods in SRE, the standard regular expression engine.
2905
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002906- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002907 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002908
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002909- Several bugs in the Unicode handling and error handling in _tkinter
2910 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002911
2912- Fix memory management errors in Merge() and Tkapp_Call() routines.
2913
2914- Several changes were made to cStringIO to make it compatible with
2915 the file-like object interface and with StringIO. If operations are
2916 performed on a closed object, an exception is raised. The truncate
2917 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002918 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002919
2920- There were many changes made to the linuxaudiodev module and its
2921 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002922 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002923
2924 Note that this module is named poorly, because it should work
2925 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002926 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002927
2928 The module now raises exceptions when errors occur instead of
2929 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2930 audio) and defines a getptr() method that calls the
2931 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2932
2933- The library_version attribute, introduced in an earlier beta, was
2934 removed because it can not be supported with early versions of the C
2935 readline library, which provides no way to determine the version at
2936 compile-time.
2937
2938- The binascii module is now enabled on Win64.
2939
Tim Peters46446d62000-10-09 21:19:31 +00002940- tokenize.py no longer suffers "recursion depth" errors when parsing
2941 programs with very long string literals.
2942
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002943Internals
2944
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002945- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002946 which is called when the interpreter starts up to determine where
2947 the standard library is installed. These vulnerabilities affect all
2948 previous versions of Python and can be exploited by setting very
2949 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2950 setuid Python script, although use of the wrapper in
2951 Misc/setuid-prog.c will eliminate the vulnerability.
2952
2953- Fixed garbage collection bugs in instance creation that were
2954 triggered when errors occurred during initialization. The solution,
2955 applied in cPickle and in PyInstance_New(), is to call
2956 PyObject_GC_Init() after the initialization of the object's
2957 container attributes is complete.
2958
2959- pyexpat adds definitions of PyModule_AddStringConstant and
2960 PyModule_AddObject if the Python version is less than 2.0, which
2961 provides compatibility with PyXML on Python 1.5.2.
2962
2963- If the platform has a bogus definition for LONG_BIT (the number of
2964 bits in a long), an error will be reported at compile time.
2965
2966- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2967 collection crashes and possibly other, unreported crashes.
2968
2969- Fixed a memory leak in _PyUnicode_Fini().
2970
2971Build issues
2972
2973- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002974 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002975 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002976
2977- The mmap.PAGESIZE constant is now initialized using sysconf when
2978 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2979
2980- The md5 file should now compile on all platforms.
2981
2982- The select module now compiles on platforms that do not define
2983 POLLRDNORM and related constants.
2984
2985- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002986 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002987
Jeremy Hylton10921202000-10-09 18:34:12 +00002988- BeOS: A number of changes were made to the build and installation
2989 process. ar-fake now operates on a directory of object files.
2990 dl_export.h is gone, and its macros now appear on the mwcc command
2991 line during build on PPC BeOS.
2992
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002993- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002994 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002995
2996- Cygwin: Support for shared libraries, Tkinter, and sockets.
2997
2998- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2999
3000Tools and other miscellany
3001
3002- Removed debugging prints from main used with freeze.
3003
Tim Peters46446d62000-10-09 21:19:31 +00003004- IDLE auto-indent no longer crashes when it encounters Unicode
3005 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003006
3007What's new in 2.0 beta 2 (since beta 1)?
3008========================================
3009
3010Core language, builtins, and interpreter
3011
Tim Peters482c0212000-09-26 06:33:09 +00003012- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003013 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003014
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003015- Add -h and -V command line options to print the usage message and
3016 Python version number and exit immediately.
3017
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003018- eval() and exec accept Unicode objects as code parameters.
3019
3020- getattr() and setattr() now also accept Unicode objects for the
3021 attribute name, which are converted to strings using the default
3022 encoding before lookup.
3023
3024- Multiplication on string and Unicode now does proper bounds
3025 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
3026 string is too long."
3027
3028- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00003029 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003030
Jeremy Hylton1b618592000-09-26 05:32:36 +00003031
3032Standard library and extensions
3033
Guido van Rossum5b08f132001-04-16 02:05:23 +00003034- socket module: the OpenSSL code now adds support for RAND_status()
3035 and EGD (Entropy Gathering Device).
3036
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003037- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00003038 argument checking; it still takes no arguments.
3039
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003040- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003041
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003042- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003043
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003044- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003045
3046- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003047 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003048
3049- copy: Copy Unicode objects atomically.
3050
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003051- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003052
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003053- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003054
Fred Drake67233bc2000-09-26 16:40:27 +00003055- dbm: Add get() and setdefault() methods to dbm object. Add constant
3056 `library' to module that names the library used. Added doc strings
3057 and method names to error messages. Uses configure to determine
3058 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
3059 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003060
3061- distutils: Update to version 0.9.3.
3062
3063- dl: Add several dl.RTLD_ constants.
3064
3065- fpectl: Now supported on FreeBSD.
3066
3067- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
3068 found by the collector will be saved in gc.garbage. This is useful
3069 for debugging a program that creates reference cycles.
3070
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003071- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00003072 of HTTP class. Do not close socket on zero-length response. Do not
3073 crash when server sends invalid content-length header.
3074
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003075- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003076
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003077- marshal: When reading a short, sign-extend on platforms where shorts
3078 are bigger than 16 bits. When reading a long, repair the unportable
3079 sign extension that was being done for 64-bit machines. (It assumed
3080 that signed right shift sign-extends.)
3081
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003082- operator: Add contains(), invert(), __invert__() as aliases for
3083 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003084
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003085- os: Add support for popen2() and popen3() on all platforms where
3086 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003087
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003088- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00003089 clicking on a file in Explorer (or passing the file name to the
3090 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003091
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003092- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00003093 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003094
3095- pickle: Now raises ValueError when an invalid pickle that contains
3096 a non-string repr where a string repr was expected. This behavior
3097 matches cPickle.
3098
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003099- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003100
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003101- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003102
3103- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003104 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003105 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003106
3107- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003108 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003109
3110- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00003111 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00003112 few cycles during startup since the first call to
3113 setdefaultencoding() will initialize the codec registry and the
3114 encodings package.
3115
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003116- socket: Support for size hint in readlines() method of object returned
3117 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003118
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003119- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00003120 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00003121 is followed by whitespace.
3122
Tim Petersa3a3a032000-11-30 05:22:44 +00003123- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003124
3125- struct: Check ranges for bytes and shorts.
3126
3127- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003128 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003129
3130- Tkinter: Image objects are now guaranteed to have unique ids. Set
3131 event.delta to zero if Tk version doesn't support mousewheel.
3132 Removed some debugging prints.
3133
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003134- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003135
Fred Drake67233bc2000-09-26 16:40:27 +00003136- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003137 which works around a bug in Norton AntiVirus 2000 that leads directly
3138 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003139
3140- xml: New version detection code allows PyXML to override standard
3141 XML package if PyXML version is greater than 0.6.1.
3142
Fred Drake64bb3802000-09-26 16:21:35 +00003143- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
3144 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
3145 tree only for nodes which are sufficiently interesting to a specific
3146 application. Does not provide the HTML-specific extensions. Still
3147 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003148
Fred Drake64bb3802000-09-26 16:21:35 +00003149- xml.sax: SAX 2 support for Python, including all the handler
3150 interfaces needed to process XML 1.0 compliant XML. Some
3151 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003152
Fred Drake64bb3802000-09-26 16:21:35 +00003153- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
3154 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003155
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003156
Jeremy Hylton1b618592000-09-26 05:32:36 +00003157C API
3158
3159- Add three new convenience functions for module initialization --
3160 PyModule_AddObject(), PyModule_AddIntConstant(), and
3161 PyModule_AddStringConstant().
3162
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003163- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00003164 removed and add #error to Python.h if NULL isn't defined after
3165 #include of stdio.h.
3166
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003167- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00003168 backwards compatibility (at the source level) with old extensions.
3169
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003170- A wrapper API was added for signal() and sigaction(). Instead of
3171 either function, always use PyOS_getsig() to get a signal handler
3172 and PyOS_setsig() to set one. A new convenience typedef
3173 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003174
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003175- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00003176 internal data buffer and size of a string object -- or the default
3177 encoded version of a Unicode object.
3178
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003179- PyString_Size() and PyString_AsString() accept Unicode objects.
3180
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003181- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00003182 exists). INT_MAX and LONG_MAX will always be defined, even if
3183 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003184
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003185- PyFloat_FromString takes a second argument, pend, that was
3186 effectively useless. It is now officially useless but preserved for
3187 backwards compatibility. If the pend argument is not NULL, *pend is
3188 set to NULL.
3189
3190- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
3191 for the attribute name. See note on getattr() above.
3192
3193- A few bug fixes to argument processing for Unicode.
3194 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
3195 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
3196 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00003197 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003198
3199- Py_BuildValue accepts B format (for bgen-generated code).
3200
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003201
Jeremy Hylton1b618592000-09-26 05:32:36 +00003202Internals
3203
3204- On Unix, fix code for finding Python installation directory so that
3205 it works when argv[0] is a relative path.
3206
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00003207- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003208 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00003209 rather than by generating a copy of the object.
3210
Tim Peters482c0212000-09-26 06:33:09 +00003211- Several of the internal Unicode tables are much smaller now, and
3212 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003213
Jeremy Hylton97693b02000-09-26 17:42:51 +00003214- In the garbage collector: Fixed bug in collection of tuples. Fixed
3215 bug that caused some instances to be removed from the container set
3216 while they were still live. Fixed parsing in gc.set_debug() for
3217 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003218
3219- Fixed refcount problem in instance deallocation that only occurred
3220 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
3221
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003222- On Windows, getpythonregpath is now protected against null data in
3223 registry key.
3224
3225- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00003226 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003227
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003228
Jeremy Hylton1b618592000-09-26 05:32:36 +00003229Build and platform-specific issues
3230
3231- Better support of GNU Pth via --with-pth configure option.
3232
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003233- Python/C API now properly exposed to dynamically-loaded extension
3234 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003235
3236- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
3237 Don't define MS_SYNC to be zero when it is undefined. Added missing
3238 prototypes in posixmodule.c.
3239
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003240- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003241 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003242
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003243- Fix largefile support on older NetBSD systems and OpenBSD by adding
3244 define for TELL64.
3245
3246
3247Tools and other miscellany
3248
3249- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
3250
3251- freeze: The modulefinder now works with 2.0 opcodes.
3252
Tim Petersa3a3a032000-11-30 05:22:44 +00003253- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003254 Move hackery of sys.argv until after the Tk instance has been
3255 created, which allows the application-specific Tkinter
3256 initialization to be executed if present; also pass an explicit
3257 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00003258
Jeremy Hylton1b618592000-09-26 05:32:36 +00003259
3260What's new in 2.0 beta 1?
3261=========================
3262
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003263Source Incompatibilities
3264------------------------
3265
3266None. Note that 1.6 introduced several incompatibilities with 1.5.2,
3267such as single-argument append(), connect() and bind(), and changes to
3268str(long) and repr(float).
3269
3270
3271Binary Incompatibilities
3272------------------------
3273
3274- Third party extensions built for Python 1.5.x or 1.6 cannot be used
3275with Python 2.0; these extensions will have to be rebuilt for Python
32762.0.
3277
3278- On Windows, attempting to import a third party extension built for
3279Python 1.5.x or 1.6 results in an immediate crash; there's not much we
3280can do about this. Check your PYTHONPATH environment variable!
3281
3282- Python bytecode files (*.pyc and *.pyo) are not compatible between
3283releases.
3284
3285
3286Overview of Changes Since 1.6
3287-----------------------------
3288
3289There are many new modules (including brand new XML support through
3290the xml package, and i18n support through the gettext module); a list
3291of all new modules is included below. Lots of bugs have been fixed.
3292
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003293The process for making major new changes to the language has changed
3294since Python 1.6. Enhancements must now be documented by a Python
3295Enhancement Proposal (PEP) before they can be accepted.
3296
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003297There are several important syntax enhancements, described in more
3298detail below:
3299
3300 - Augmented assignment, e.g. x += 1
3301
3302 - List comprehensions, e.g. [x**2 for x in range(10)]
3303
3304 - Extended import statement, e.g. import Module as Name
3305
3306 - Extended print statement, e.g. print >> file, "Hello"
3307
3308Other important changes:
3309
3310 - Optional collection of cyclical garbage
3311
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003312Python Enhancement Proposal (PEP)
3313---------------------------------
3314
3315PEP stands for Python Enhancement Proposal. A PEP is a design
3316document providing information to the Python community, or describing
3317a new feature for Python. The PEP should provide a concise technical
3318specification of the feature and a rationale for the feature.
3319
3320We intend PEPs to be the primary mechanisms for proposing new
3321features, for collecting community input on an issue, and for
3322documenting the design decisions that have gone into Python. The PEP
3323author is responsible for building consensus within the community and
3324documenting dissenting opinions.
3325
3326The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003327
3328Augmented Assignment
3329--------------------
3330
3331This must have been the most-requested feature of the past years!
3332Eleven new assignment operators were added:
3333
Guido van Rossume905e952000-09-05 12:42:46 +00003334 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003335
3336For example,
3337
3338 A += B
3339
3340is similar to
3341
3342 A = A + B
3343
3344except that A is evaluated only once (relevant when A is something
3345like dict[index].attr).
3346
3347However, if A is a mutable object, A may be modified in place. Thus,
3348if A is a number or a string, A += B has the same effect as A = A+B
3349(except A is only evaluated once); but if a is a list, A += B has the
3350same effect as A.extend(B)!
3351
3352Classes and built-in object types can override the new operators in
3353order to implement the in-place behavior; the not-in-place behavior is
3354used automatically as a fallback when an object doesn't implement the
3355in-place behavior. For classes, the method name is derived from the
3356method name for the corresponding not-in-place operator by inserting
3357an 'i' in front of the name, e.g. __iadd__ implements in-place
3358__add__.
3359
3360Augmented assignment was implemented by Thomas Wouters.
3361
3362
3363List Comprehensions
3364-------------------
3365
3366This is a flexible new notation for lists whose elements are computed
3367from another list (or lists). The simplest form is:
3368
3369 [<expression> for <variable> in <sequence>]
3370
Guido van Rossum56db0952000-09-06 23:34:25 +00003371For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003372This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003373
3374You can also add a condition:
3375
3376 [<expression> for <variable> in <sequence> if <condition>]
3377
3378For example, [w for w in words if w == w.lower()] would yield the list
3379of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003380than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003381
3382You can also have nested for loops and more than one 'if' clause. For
3383example, here's a function that flattens a sequence of sequences::
3384
3385 def flatten(seq):
3386 return [x for subseq in seq for x in subseq]
3387
3388 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3389
3390This prints
3391
3392 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3393
3394List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003395Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003396
3397
3398Extended Import Statement
3399-------------------------
3400
3401Many people have asked for a way to import a module under a different
3402name. This can be accomplished like this:
3403
3404 import foo
3405 bar = foo
3406 del foo
3407
3408but this common idiom gets old quickly. A simple extension of the
3409import statement now allows this to be written as follows:
3410
3411 import foo as bar
3412
3413There's also a variant for 'from ... import':
3414
3415 from foo import bar as spam
3416
3417This also works with packages; e.g. you can write this:
3418
3419 import test.regrtest as regrtest
3420
3421Note that 'as' is not a new keyword -- it is recognized only in this
3422context (this is only possible because the syntax for the import
3423statement doesn't involve expressions).
3424
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003425Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003426
3427
3428Extended Print Statement
3429------------------------
3430
3431Easily the most controversial new feature, this extension to the print
3432statement adds an option to make the output go to a different file
3433than the default sys.stdout.
3434
3435For example, to write an error message to sys.stderr, you can now
3436write:
3437
3438 print >> sys.stderr, "Error: bad dog!"
3439
3440As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003441evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003442
3443 print >> None, "Hello world"
3444
3445is equivalent to
3446
3447 print "Hello world"
3448
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003449Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003450
3451
3452Optional Collection of Cyclical Garbage
3453---------------------------------------
3454
3455Python is now equipped with a garbage collector that can hunt down
3456cyclical references between Python objects. It's no replacement for
3457reference counting; in fact, it depends on the reference counts being
3458correct, and decides that a set of objects belong to a cycle if all
3459their reference counts can be accounted for from their references to
3460each other. This devious scheme was first proposed by Eric Tiedemann,
3461and brought to implementation by Neil Schemenauer.
3462
3463There's a module "gc" that lets you control some parameters of the
3464garbage collection. There's also an option to the configure script
3465that lets you enable or disable the garbage collection. In 2.0b1,
3466it's on by default, so that we (hopefully) can collect decent user
3467experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003468performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003469off by default in the final 2.0 release.
3470
3471
3472Smaller Changes
3473---------------
3474
3475A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3476map(None, seq1, seq2, ...) when the sequences have the same length;
3477i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3478the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003479zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003480
3481sys.version_info is a tuple (major, minor, micro, level, serial).
3482
3483Dictionaries have an odd new method, setdefault(key, default).
3484dict.setdefault(key, default) returns dict[key] if it exists; if not,
3485it sets dict[key] to default and returns that value. Thus:
3486
3487 dict.setdefault(key, []).append(item)
3488
3489does the same work as this common idiom:
3490
3491 if not dict.has_key(key):
3492 dict[key] = []
3493 dict[key].append(item)
3494
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003495There are two new variants of SyntaxError that are raised for
3496indentation-related errors: IndentationError and TabError.
3497
3498Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3499escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003500
3501The limits on the size of expressions and file in Python source code
3502have been raised from 2**16 to 2**32. Previous versions of Python
3503were limited because the maximum argument size the Python VM accepted
3504was 2**16. This limited the size of object constructor expressions,
3505e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3506limit was raised thanks to a patch by Charles Waldman that effectively
3507fixes the problem. It is now much more likely that you will be
3508limited by available memory than by an arbitrary limit in Python.
3509
3510The interpreter's maximum recursion depth can be modified by Python
3511programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3512limit is the maximum number of recursive calls that can be made by
3513Python code. The limit exists to prevent infinite recursion from
3514overflowing the C stack and causing a core dump. The default value is
35151000. The maximum safe value for a particular platform can be found
3516by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003517
3518New Modules and Packages
3519------------------------
3520
3521atexit - for registering functions to be called when Python exits.
3522
3523imputil - Greg Stein's alternative API for writing custom import
3524hooks.
3525
3526pyexpat - an interface to the Expat XML parser, contributed by Paul
3527Prescod.
3528
3529xml - a new package with XML support code organized (so far) in three
3530subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3531would fill a volume. There's a special feature whereby a
3532user-installed package named _xmlplus overrides the standard
3533xmlpackage; this is intended to give the XML SIG a hook to distribute
3534backwards-compatible updates to the standard xml package.
3535
3536webbrowser - a platform-independent API to launch a web browser.
3537
3538
Guido van Rossume905e952000-09-05 12:42:46 +00003539Changed Modules
3540---------------
3541
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003542array -- new methods for array objects: count, extend, index, pop, and
3543remove
3544
3545binascii -- new functions b2a_hex and a2b_hex that convert between
3546binary data and its hex representation
3547
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003548calendar -- Many new functions that support features including control
3549over which day of the week is the first day, returning strings instead
3550of printing them. Also new symbolic constants for days of week,
3551e.g. MONDAY, ..., SUNDAY.
3552
3553cgi -- FieldStorage objects have a getvalue method that works like a
3554dictionary's get method and returns the value attribute of the object.
3555
3556ConfigParser -- The parser object has new methods has_option,
3557remove_section, remove_option, set, and write. They allow the module
3558to be used for writing config files as well as reading them.
3559
3560ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003561optionally support the RFC 959 REST command.
3562
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003563gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003564
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003565httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3566the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003567
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003568locale -- implement getdefaultlocale for Win32 and Macintosh
3569
3570marshal -- no longer dumps core when marshaling deeply nested or
3571recursive data structures
3572
3573os -- new functions isatty, seteuid, setegid, setreuid, setregid
3574
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003575os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3576support under Unix.
3577
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003578os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003579
3580os.path -- fix semantics of os.path.commonprefix
3581
3582smtplib -- support for sending very long messages
3583
3584socket -- new function getfqdn()
3585
3586readline -- new functions to read, write and truncate history files.
3587The readline section of the library reference manual contains an
3588example.
3589
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003590select -- add interface to poll system call
3591
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003592shutil -- new copyfileobj function
3593
3594SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3595HTTP server.
3596
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003597Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003598
3599urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003600e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003601
3602whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003603
3604
3605Obsolete Modules
3606----------------
3607
3608None. However note that 1.6 made a whole slew of modules obsolete:
3609stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3610poly, zmod, strop, util, whatsound.
3611
3612
3613Changed, New, Obsolete Tools
3614----------------------------
3615
Tim Peters8b092332000-09-05 20:15:25 +00003616None.
Guido van Rossume905e952000-09-05 12:42:46 +00003617
3618
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003619C-level Changes
3620---------------
3621
3622Several cleanup jobs were carried out throughout the source code.
3623
3624All C code was converted to ANSI C; we got rid of all uses of the
3625Py_PROTO() macro, which makes the header files a lot more readable.
3626
3627Most of the portability hacks were moved to a new header file,
3628pyport.h; several other new header files were added and some old
3629header files were removed, in an attempt to create a more rational set
3630of header files. (Few of these ever need to be included explicitly;
3631they are all included by Python.h.)
3632
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003633Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003634and Win64, especially for the new Intel Itanium processor. Mick also
3635added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003636
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003637The C APIs to return an object's size have been update to consistently
3638use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3639previous versions, the abstract interfaces used PyXXX_Length and the
3640concrete interfaces used PyXXX_Size. The old names,
3641e.g. PyObject_Length, are still available for backwards compatibility
3642at the API level, but are deprecated.
3643
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003644The PyOS_CheckStack function has been implemented on Windows by
3645Fredrik Lundh. It prevents Python from failing with a stack overflow
3646on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003647
3648The GC changes resulted in creation of two new slots on object,
3649tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003650the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003651
3652The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003653C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003654
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003655PyErr_Format has been updated to automatically calculate the size of
3656the buffer needed to hold the formatted result string. This change
3657prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003658
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003659New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003660
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003661PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3662that are the same as their non-Ex counterparts except they take an
3663extra flag argument that tells them to close the file when done.
3664
3665XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003666
Tim Peters8b092332000-09-05 20:15:25 +00003667
3668Windows Changes
3669---------------
3670
3671New popen2/popen3/peopen4 in os module (see Changed Modules above).
3672
3673os.popen is much more usable on Windows 95 and 98. See Microsoft
3674Knowledge Base article Q150956. The Win9x workaround described there
3675is implemented by the new w9xpopen.exe helper in the root of your
3676Python installation. Note that Python uses this internally; it is not
3677a standalone program.
3678
3679Administrator privileges are no longer required to install Python
3680on Windows NT or Windows 2000. If you have administrator privileges,
3681Python's registry info will be written under HKEY_LOCAL_MACHINE.
3682Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003683under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003684uses of Python, but will prevent some advanced uses from working
3685(for example, running a Python script as an NT service, or possibly
3686from CGI).
3687
3688[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3689installer; instead, it installs the needed Tcl/Tk files directly in the
3690Python directory. If you already have a Tcl/Tk installation, this
3691wastes some disk space (about 4 Megs) but avoids problems with
3692conflicting Tcl/Tk installations, and makes it much easier for Python
3693to ensure that Tcl/Tk can find all its files.
3694
3695[This was new in 1.6] The Windows installer now installs by default in
3696\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3697
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003698
3699Updates to the changes between 1.5.2 and 1.6
3700--------------------------------------------
3701
3702The 1.6 NEWS file can't be changed after the release is done, so here
3703is some late-breaking news:
3704
3705New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3706and changes to getlocale() and setlocale().
3707
3708The new module is now enabled per default.
3709
3710It is not true that the encodings codecs cannot be used for normal
3711strings: the string.encode() (which is also present on 8-bit strings
3712!) allows using them for 8-bit strings too, e.g. to convert files from
3713cp1252 (Windows) to latin-1 or vice-versa.
3714
3715Japanese codecs are available from Tamito KAJIYAMA:
3716http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3717
3718
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003719======================================================================