blob: 9d278b646a16851d8dcb05a7d2559beee775e134 [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
Guido van Rossume3438782002-08-12 03:42:03 +00007- Assignment to __class__ is disallowed if either the old and the new
8 class is a statically allocated type object (such as defined by an
9 extenson module). This prevents anomalies like 2.__class__ = bool.
10
11- New-style object creation and deallocation have been sped up
12 significantly; they are now faster than classic instance creation
13 and deallocation.
14
15- The __slots__ variable can now mention "private" names, and the
16 right thing will happen (e.g. __slots__ = ["__foo"]).
17
18- The built-ins slice() and buffer() are now callable types. The
19 types classobj (formerly class), code, function, instance, and
20 instancemethod (formerly instance-method), which have no built-in
21 names but are accessible through the types module, are now also
22 callable. The type dict-proxy is renamed to dictproxy.
23
24- Cycles going through the __class__ link of a new-style instance are
25 now detected by the garbage collector.
26
27- Classes using __slots__ are now properly garbage collected.
28 [SF bug 519621]
29
30- Tightened the __slots__ rules: a slot name must be a valid Python
31 identifier.
32
33- The constructor for the module type now requires a name argument and
34 takes an optional docstring argument. Previously, this constructor
35 ignored its arguments. As a consequence, deriving a class from a
36 module (not from the module type) is now illegal; previously this
37 created an unnamed module, just like invoking the module type did.
38 [SF bug 563060]
39
40- A new type object, 'basestring', is added. This is a common base type
41 for 'str' and 'unicode', and can be used instead of
42 types.StringTypes, e.g. to test whether something is "a string":
43 isinstance(x, basestring) is True for Unicode and 8-bit strings. This
44 is an abstract base class and cannot be instantiated directly.
45
46- Changed new-style class instantiation so that when C's __new__
47 method returns something that's not a C instance, its __init__ is
48 not called. [SF bug #537450]
49
50- Fixed super() to work correctly with class methods. [SF bug #535444]
51
52- If you try to pickle an instance of a class that has __slots__ but
53 doesn't define or override __getstate__, a TypeError is now raised.
54 This is done by adding a bozo __getstate__ to the class that always
55 raises TypeError. (Before, this would appear to be pickled, but the
56 state of the slots would be lost.)
57
Tim Petersaf8446f2001-12-21 21:36:50 +000058Core and builtins
59
Tim Peters5af4e6c2002-08-12 02:31:19 +000060- XXX Karatsuba multiplication. This is currently used if and only
61 if envar KARAT exists. It needs more correctness and speed testing,
62 the latter especially with unbalanced bit lengths.
63
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +000064- u'%c' will now raise a ValueError in case the argument is an
65 integer outside the valid range of Unicode code point ordinals.
66
Guido van Rossumdeb09362002-08-09 17:16:30 +000067- The tempfile module has been overhauled for enhanced security. The
68 mktemp() function is now deprecated; new, safe replacements are
69 mkstemp() (for files) and mkdtemp() (for directories), and the
70 higher-level functions NamedTemporaryFile() and TemporaryFile().
71 Use of some global variables in this module is also deprecated; the
72 new functions have keyword arguments to provide the same
73 functionality. All Lib, Tools and Demo modules that used the unsafe
74 interfaces have been updated to use the safe replacements. Thanks
75 to Zack Weinberg!
76
Guido van Rossumd81a9832002-08-09 15:57:34 +000077- When x is an object whose class implements __mul__ and __rmul__,
78 1.0*x would correctly invoke __rmul__, but 1*x would erroneously
79 invoke __mul__. This was due to the sequence-repeat code in the int
80 type. This has been fixed now.
81
Barry Warsawd79f6832002-08-06 17:01:51 +000082- Previously, "str1 in str2" required str1 to be a string of length 1.
83 This restriction has been relaxed to allow str1 to be a string of
84 any length. Thus "'el' in 'hello world'" returns True now.
85
Guido van Rossumb57089c2002-08-06 16:20:26 +000086- File objects are now their own iterators. For a file f, iter(f) now
87 returns f (unless f is closed), and f.next() is similar to
88 f.readline() when EOF is not reached; however, f.next() uses a
89 readahead buffer that messes up the file position, so mixing
90 f.next() and f.readline() (or other methods) doesn't work right.
91 Calling f.seek() drops the readahead buffer, but other operations
92 don't. It so happens that this gives a nice additional speed boost
93 to "for line in file:"; the xreadlines method and corresponding
Guido van Rossumbffb2ef2002-08-09 17:17:07 +000094 module are now obsolete. Thanks to Oren Tirosh!
Guido van Rossumb57089c2002-08-06 16:20:26 +000095
Guido van Rossumde392d32002-08-05 14:17:20 +000096- Encoding declarations (PEP 263, phase 1) have been implemented. A
97 comment of the form "# -*- coding: <encodingname> -*-" in the first
98 or second line of a Python source file indicates the encoding.
Martin v. Löwis00f1e3f2002-08-04 17:29:52 +000099
Tim Petersf47630f2002-08-01 02:34:51 +0000100- list.sort() has a new implementation. While cross-platform results
101 may vary, and in data-dependent ways, this is much faster on many
102 kinds of partially ordered lists than the previous implementation,
103 and reported to be just as fast on randomly ordered lists on
104 several major platforms. This sort is also stable (if A==B and A
105 precedes B in the list at the start, A precedes B after the sort too),
106 although the language definition does not guarantee stability. A
107 potential drawback is that list.sort() may require temp space of
108 len(list)*2 bytes (*4 on a 64-bit machine). It's therefore possible
109 for list.sort() to raise MemoryError now, even if a comparison function
110 does not. See <http://www.python.org/sf/587076> for full details.
111
Guido van Rossum2d5389c2002-07-23 03:44:35 +0000112- All standard iterators now ensure that, once StopIteration has been
113 raised, all future calls to next() on the same iterator will also
114 raise StopIteration. There used to be various counterexamples to
115 this behavior, which could caused confusion or subtle program
116 breakage, without any benefits. (Note that this is still an
117 iterator's responsibility; the iterator framework does not enforce
118 this.)
119
Mark Hammondc0e35152002-07-16 01:32:30 +0000120- Ctrl+C handling on Windows has been made more consistent with
121 other platforms. KeyboardInterrupt can now reliably be caught,
Tim Petersf47630f2002-08-01 02:34:51 +0000122 and Ctrl+C at an interative prompt no longer terminates the
Mark Hammondc0e35152002-07-16 01:32:30 +0000123 process under NT/2k/XP (it never did under Win9x). Ctrl+C will
Tim Peters5af4e6c2002-08-12 02:31:19 +0000124 interrupt time.sleep() in the main thread, and any child processes
125 created via the popen family (on win2k; we can't make win9x work
Mark Hammond8f3afc72002-08-10 06:26:31 +0000126 reliably) are also interrupted (as generally happens on for Linux/Unix.)
127 [SF bugs 231273, 439992 and 581232]
Mark Hammondc0e35152002-07-16 01:32:30 +0000128
Raymond Hettinger5a04aec2002-06-25 00:25:30 +0000129- Slices and repetitions of buffer objects now consistently return
130 a string. Formerly, strings would be returned most of the time,
131 but a buffer object would be returned when the repetition count
132 was one or when the slice range was all inclusive.
133
Walter Dörwald3430d702002-06-17 10:43:59 +0000134- Unicode objects in sys.path are no longer ignored but treated
135 as directory names.
136
Neal Norwitz1f68fc72002-06-14 00:50:42 +0000137- Fixed string.startswith and string.endswith builtin methods
138 so they accept negative indices. [SF bug 493951]
139
Guido van Rossumc5fe5eb2002-06-12 03:45:21 +0000140- Fixed a bug with a continue inside a try block and a yield in the
141 finally clause. [SF bug 567538]
142
Michael W. Hudson5efaf7e2002-06-11 10:55:12 +0000143- Most builtin sequences now support "extended slices", i.e. slices
Guido van Rossum2e82e712002-06-13 11:41:07 +0000144 with a third "stride" parameter. For example, "hello world"[::-1]
145 gives "dlrow olleh".
Michael W. Hudson5efaf7e2002-06-11 10:55:12 +0000146
Neal Norwitzd68f5172002-05-29 15:54:55 +0000147- A new warning PendingDeprecationWarning was added to provide
148 direction on features which are in the process of being deprecated.
149 The warning will not be printed by default. To see the pending
150 deprecations, use -Walways::PendingDeprecationWarning::
151 as a command line option or warnings.filterwarnings() in code.
152
Fred Draked0ba6362002-05-02 21:28:26 +0000153- Deprecated features of xrange objects have been removed as
154 promised. The start, stop, and step attributes and the tolist()
155 method no longer exist. xrange repetition and slicing have been
156 removed.
157
Guido van Rossum7dab2422002-04-26 19:40:56 +0000158- New builtin function enumerate(x), from PEP 279. Example:
159 enumerate("abc") is an iterator returning (0,"a"), (1,"b"), (2,"c").
160 The argument can be an arbitrary iterable object.
161
Neil Schemenauer89e3ee02002-04-26 01:58:53 +0000162- The assert statement no longer tests __debug__ at runtime. This means
163 that assert statements cannot be disabled by assigning a false value
164 to __debug__.
165
Walter Dörwald068325e2002-04-15 13:36:47 +0000166- A method zfill() was added to str and unicode, that fills a numeric
167 string to the left with zeros. For example,
168 "+123".zfill(6) -> "+00123".
169
Guido van Rossum862fe3c2002-04-15 12:36:47 +0000170- Complex numbers supported divmod() and the // and % operators, but
171 these make no sense. Since this was documented, they're being
172 deprecated now.
173
Guido van Rossum26dd8302002-04-26 20:11:29 +0000174- String and unicode methods lstrip(), rstrip() and strip() now take
175 an optional argument that specifies the characters to strip. For
176 example, "Foo!!!?!?!?".rstrip("?!") -> "Foo".
Guido van Rossum49042042002-04-13 00:59:05 +0000177
Guido van Rossumc69343b2002-04-12 19:22:48 +0000178- Added a new dict method pop(key). This removes and returns the
179 value corresponding to key. [SF patch #539949]
180
Guido van Rossum47834462002-04-04 15:21:33 +0000181- A new built-in type, bool, has been added, as well as built-in
182 names for its two values, True and False. Comparisons and sundry
183 other operations that return a truth value have been changed to
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000184 return a bool instead. Read PEP 285 for an explanation of why this
Guido van Rossum47834462002-04-04 15:21:33 +0000185 is backward compatible.
186
Guido van Rossum95b62a62002-03-29 01:07:24 +0000187- Fixed two bugs reported as SF #535905: under certain conditions,
188 deallocating a deeply nested structure could cause a segfault in the
189 garbage collector, due to interaction with the "trashcan" code;
190 access to the current frame during destruction of a local variable
191 could access a pointer to freed memory.
192
Guido van Rossumfe0ca4a2002-06-18 21:20:13 +0000193- The optional object allocator ("pymalloc") has been enabled by
194 default. The recommended practice for memory allocation and
195 deallocation has been streamlined. A header file is included,
196 Misc/pymemcompat.h, which can be bundled with 3rd party extensions
197 and lets them use the same API with Python versions from 1.5.2
198 onwards.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000199
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +0000200- PyErr_Display will provide file and line information for all exceptions
201 that have an attribute print_file_and_line, not just SyntaxErrors.
202
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000203- The UTF-8 codec will now encode and decode Unicode surrogates
204 correctly and without raising exceptions for unpaired ones.
205
Neal Norwitz649b7592002-01-01 19:07:13 +0000206- file.xreadlines() now raises a ValueError if the file is closed:
207 Previously, an xreadlines object was returned which would raise
208 a ValueError when the xreadlines.next() method was called.
209
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000210- sys.exit() inadvertently allowed more than one argument.
Neal Norwitz0c766a02002-03-27 13:03:09 +0000211 An exception will now be raised if more than one argument is used.
212
Tim Petersaf8446f2001-12-21 21:36:50 +0000213Extension modules
214
Guido van Rossumb57089c2002-08-06 16:20:26 +0000215- The xreadlines module is slated for obsolescence.
216
Guido van Rossum79f0a102002-07-23 03:32:08 +0000217- The strptime function in the time module is now always available (a
218 Python implementation is used when the C library doesn't define it).
219
Guido van Rossum9562bcf2002-06-14 21:31:18 +0000220- The 'new' module is no longer an extension, but a Python module that
221 only exists for backwards compatibility. Its contents are no longer
222 functions but callable type objects.
223
Tim Peters81b92512002-04-29 01:37:32 +0000224- The bsddb.*open functions can now take 'None' as a filename.
Anthony Baxter83888952002-04-23 02:11:05 +0000225 This will create a temporary in-memory bsddb that won't be
Tim Peters81b92512002-04-29 01:37:32 +0000226 written to disk.
Anthony Baxter83888952002-04-23 02:11:05 +0000227
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000228- posix.lchown, posix.killpg, posix.mknod, and posix.getpgid have been
229 added where available.
Martin v. Löwis06a83e92002-04-14 10:19:44 +0000230
Martin v. Löwis2e64c342002-03-27 18:49:02 +0000231- The locale module now exposes the C library's gettext interface.
232
Tim Petersfbf74f22002-03-14 19:06:01 +0000233- A security hole ("double free") was found in zlib-1.1.3, a popular
234 third party compression library used by some Python modules. The
235 hole was quickly plugged in zlib-1.1.4, and the Windows build of
236 Python now ships with zlib-1.1.4.
237
Martin v. Löwis688357e2002-04-08 21:28:20 +0000238- pwd, grp, and resource return enhanced tuples now, with symbolic
239 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +0000240
Martin v. Löwis99866332002-03-01 10:27:01 +0000241- array.array is now a type object. A new format character
242 'u' indicates Py_UNICODE arrays. For those, .tounicode and
243 .fromunicode methods are available. Arrays now support __iadd__
244 and __imul__.
245
Neal Norwitze790eae2002-01-01 21:14:12 +0000246- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +0000247 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
248 is called.
249
Michael W. Hudson34f20ea2002-05-27 15:08:24 +0000250- signal.sigpending, signal.sigprocmask and signal.sigsuspend have
251 been added where available.
252
Tim Petersaf8446f2001-12-21 21:36:50 +0000253Library
254
Guido van Rossum4a57c332002-08-02 18:05:20 +0000255- New "algorithms" module: heapq, implements a heap queue. Thanks to
256 Kevin O'Connor for the code and François Pinard for an entertaining
257 write-up explaining the theory and practical uses of heaps.
258
Marc-André Lemburg58e2ff22002-07-12 14:40:04 +0000259- New encoding for the Palm OS character set: palmos.
260
Tim Peters943382c2002-07-07 03:59:34 +0000261- binascii.crc32() and the zipfile module had problems on some 64-bit
262 platforms. These have been fixed. On a platform with 8-byte C longs,
263 crc32() now returns a signed-extended 4-byte result, so that its value
264 as a Python int is equal to the value computed a 32-bit platform.
265
Martin v. Löwis7d650ca2002-06-30 15:05:00 +0000266- xml.dom.minidom.toxml and toprettyxml now take an optional encoding
267 argument.
268
Guido van Rossum9f7549b2002-06-10 21:39:42 +0000269- Some fixes in the copy module: when an object is copied through its
270 __reduce__ method, there was no check for a __setstate__ method on
271 the result [SF patch 565085]; deepcopy should treat instances of
272 custom metaclasses the same way it treats instances of type 'type'
273 [SF patch 560794].
274
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000275- Sockets now support timeout mode. After s.settimeout(T), where T is
276 a float expressing seconds, subsequent operations raise an exception
277 if they cannot be completed within T seconds. To disable timeout
Guido van Rossum79f0a102002-07-23 03:32:08 +0000278 mode, use s.settimeout(None). There's also a module function,
279 socket.setdefaulttimeout(T), which sets the default for all sockets
280 created henceforth.
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000281
282- getopt.gnu_getopt was added. This supports GNU-style option
283 processing, where options can be mixed with non-option arguments.
Martin v. Löwis446a25f2002-06-06 10:58:36 +0000284
Michael W. Hudsonb0dc1a32002-06-04 18:27:35 +0000285- Stop using strings for exceptions. String objects used for
286 exceptions are now classes deriving from Exception. The objects
287 changed were: Tkinter.TclError, bdb.BdbQuit, macpath.norm_error,
288 tabnanny.NannyNag, and xdrlib.Error.
Neal Norwitzb5b5a262002-06-04 17:14:07 +0000289
Walter Dörwald474458d2002-06-04 15:16:29 +0000290- Constants BOM_UTF8, BOM_UTF16, BOM_UTF16_LE, BOM_UTF16_BE,
291 BOM_UTF32, BOM_UTF32_LE and BOM_UTF32_BE that represent the Byte
292 Order Mark in UTF-8, UTF-16 and UTF-32 encodings for little and
293 big endian systems were added to the codecs module. The old names
294 BOM32_* and BOM64_* were off by a factor of 2.
295
Guido van Rossumf9257822002-06-18 20:43:18 +0000296- Added conversion functions math.degrees() and math.radians().
Raymond Hettinger87f59ee2002-05-13 04:17:32 +0000297
Raymond Hettinger9b1df1d2002-05-12 06:07:21 +0000298- ftplib.retrlines() now tests for callback is None rather than testing
299 for False. Was causing an error when given a callback object which
300 was callable but also returned len() as zero. The change may
301 create new breakage if the caller relied on the undocumented behavior
302 and called with callback set to [] or some other False value not
303 identical to None.
304
Tim Peters46c04e12002-05-05 20:40:00 +0000305- random.gauss() uses a piece of hidden state used by nothing else,
306 and the .seed() and .whseed() methods failed to reset it. In other
307 words, setting the seed didn't completely determine the sequence of
308 results produced by random.gauss(). It does now. Programs repeatedly
309 mixing calls to a seed method with calls to gauss() may see different
310 results now.
311
Fred Drake7f781c92002-05-01 20:33:53 +0000312- The pickle.Pickler class grew a clear_memo() method to mimic that
313 provided by cPickle.Pickler.
314
Tim Peters81b92512002-04-29 01:37:32 +0000315- difflib's SequenceMatcher class now does a dynamic analysis of
316 which elements are so frequent as to constitute noise. For
317 comparing files as sequences of lines, this generally works better
318 than the IS_LINE_JUNK function, and function ndiff's linejunk
319 argument defaults to None now as a result. A happy benefit is
320 that SequenceMatcher may run much faster now when applied
321 to large files with many duplicate lines (for example, C program
322 text with lots of repeated "}" and "return NULL;" lines).
323
Guido van Rossum256705b2002-04-23 13:29:43 +0000324- New Text.dump() method in Tkinter module.
325
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000326- New distutils commands for building packagers were added to
327 support pkgtool on Solaris and swinstall on HP-UX.
328
329- distutils now has a new abstract binary packager base class
330 command/bdist_packager, which simplifies writing packagers.
331 This will hopefully provide the missing bits to encourage
332 people to submit more packagers, e.g. for Debian, FreeBSD
333 and other systems.
334
Guido van Rossumf9257822002-06-18 20:43:18 +0000335- The UTF-16, -LE and -BE stream readers now raise a
336 NotImplementedError for all calls to .readline(). Previously, they
337 used to just produce garbage or fail with an encoding error --
338 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 +0000339 work well with these.
340
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000341- compileall now supports quiet operation.
342
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000343- The BaseHTTPServer now implements optional HTTP/1.1 persistent
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000344 connections.
345
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000346- socket module: the SSL support was broken out of the main
347 _socket module C helper and placed into a new _ssl helper
348 which now gets imported by socket.py if available and working.
349
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000350- encodings package: added aliases for all supported IANA character
351 sets
352
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000353- ftplib: to safeguard the user's privacy, anonymous login will use
354 "anonymous@" as default password, rather than the real user and host
355 name.
356
Fred Drake36736122002-01-10 13:50:31 +0000357- webbrowser: tightened up the command passed to os.system() so that
358 arbitrary shell code can't be executed because a bogus URL was
359 passed in.
360
Tim Peters11bd9942002-02-01 00:52:29 +0000361- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000362 gettext.find an optional all argument. Translations will now fallback
363 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000364
Martin v. Löwis9668b932002-01-12 11:27:42 +0000365- distutils bdist commands now offer a --skip-build option.
366
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000367- warnings.warn now accepts a Warning instance as first argument.
368
Fred Drakefed7e852002-04-04 19:36:15 +0000369- The xml.sax.expatreader.ExpatParser class will no longer create
370 circular references by using itself as the locator that gets passed
371 to the content handler implementation. [SF bug #535474]
372
Barry Warsaw47f3e2c2002-05-20 00:14:24 +0000373- The email.Parser.Parser class now properly parses strings regardless
374 of their line endings, which can be any of \r, \n, or \r\n (CR, LF,
375 or CRLF). Also, the Header class's constructor default arguments
376 has changed slightly so that an explicit maxlinelen value is always
377 honored.
378
Tim Petersaf8446f2001-12-21 21:36:50 +0000379Tools/Demos
380
Fred Drake40813b12002-08-05 15:24:19 +0000381- IDLE supports the new encoding declarations (PEP 263); it can also
382 deal with legacy 8-bit files if they use the locale's encoding. It
383 allows non-ASCII strings in the interactive shell and executes them
384 in the locale's encoding.
Martin v. Löwis98ce7b72002-08-05 15:11:26 +0000385
Marc-André Lemburg46260092002-04-04 16:17:11 +0000386- freeze.py now produces binaries which can import shared modules,
387 unlike before when this failed due to missing symbol exports in
388 the generated binary.
389
Tim Petersaf8446f2001-12-21 21:36:50 +0000390Build
391
Tim Petersf47630f2002-08-01 02:34:51 +0000392- The public Python C API will generally be declared using PyAPI_FUNC
Neal Norwitz1389f3e2002-07-22 13:21:10 +0000393 and PyAPI_DATA macros, while Python extension module init functions
394 will be declared with PyMODINIT_FUNC. DL_EXPORT/DL_IMPORT macros
395 are deprecated.
396
Tim Petersc6a3ff62002-07-08 22:11:52 +0000397- A bug was fixed that could cause COUNT_ALLOCS builds to segfault, or
398 get into infinite loops, when a new-style class got garbage-collected.
399 Unfortunately, to avoid this, the way COUNT_ALLOCS works requires
400 that new-style classes be immortal in COUNT_ALLOCS builds. Note that
401 COUNT_ALLOCS is not enabled by default, in either release or debug
402 builds, and that new-style classes are immortal only in COUNT_ALLOCS
403 builds.
404
Tim Peters943382c2002-07-07 03:59:34 +0000405- Compiling out the cyclic garbage collector is no longer an option.
406 The old symbol WITH_CYCLE_GC is now ignored, and Python.h arranges
407 that it's always defined (for the benefit of any extension modules
408 that may be conditionalizing on it). A bonus is that any extension
409 type participating in cyclic gc can choose to participate in the
410 Py_TRASHCAN mechanism now too; in the absence of cyclic gc, this used
411 to require editing the core to teach the trashcan mechanism about the
412 new type.
413
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000414- According to Annex F of the current C standard,
Tim Peters1de41bf2002-07-03 03:31:20 +0000415
416 The Standard C macro HUGE_VAL and its float and long double analogs,
417 HUGE_VALF and HUGE_VALL, expand to expressions whose values are
418 positive infinities.
419
420 Python only uses the double HUGE_VAL, and only to #define its own symbol
421 Py_HUGE_VAL. Some platforms have incorrect definitions for HUGE_VAL.
422 pyport.h used to try to worm around that, but the workarounds triggered
423 other bugs on other platforms, so we gave up. If your platform defines
424 HUGE_VAL incorrectly, you'll need to #define Py_HUGE_VAL to something
425 that works on your platform. The only instance of this I'm sure about
426 is on an unknown subset of Cray systems, described here:
427
428 http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm
429
430 Presumably 2.3a1 breaks such systems. If anyone uses such a system, help!
431
Martin v. Löwisa3fb4f72002-06-09 13:33:54 +0000432- The configure option --without-doc-strings can be used to remove the
433 doc strings from the builtin functions and modules; this reduces the
434 size of the executable.
435
Tim Peters639295f2002-04-21 07:30:30 +0000436- XXX WITH_UNIVERSAL_NEWLINES Somebody fill this in; the PEP doesn't
437 say how or when to configure it, or how to turn it off.
438
Martin v. Löwis1142de32002-03-29 16:28:31 +0000439- On Unix, a shared libpython2.3.so can be created with --enable-shared.
440
Tim Peters8deda702002-03-30 10:06:07 +0000441- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
442 preprocessor symbols were eliminated. The internal decisions they
443 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000444
Fred Drake7d28b732002-05-02 21:17:00 +0000445- The tools used to build the documentation now work under Cygwin as
446 well as Unix.
447
Skip Montanaro57454e52002-06-14 20:30:31 +0000448- The bsddb and dbm module builds have been changed to try and avoid version
449 skew problems and disable linkage with Berkeley DB 1.85 unless the
450 installer knows what s/he's doing. See the section on building these
451 modules in the README file for details.
452
Tim Petersaf8446f2001-12-21 21:36:50 +0000453C API
454
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +0000455- New C API PyUnicode_FromOrdinal() which exposes unichr() at C
456 level.
457
Thomas Heller085358a2002-07-29 14:27:41 +0000458- New functions PyErr_SetExcFromWindowsErr() and
459 PyErr_SetExcFromWindowsErrWithFilename(). Similar to
460 PyErr_SetFromWindowsErrWithFilename() and
461 PyErr_SetFromWindowsErr(), but they allow to specify
462 the exception type to raise. Available on Windows.
463
Tim Peters7c321a82002-07-09 02:57:01 +0000464- Py_FatalError() is now declared as taking a const char* argument. It
465 was previously declared without const. This should not affect working
466 code.
467
Martin v. Löwis01f94bd2002-05-08 08:44:21 +0000468- Added new macro PySequence_ITEM(o, i) that directly calls
469 sq_item without rechecking that o is a sequence and without
470 adjusting for negative indices.
471
Fred Draked0ba6362002-05-02 21:28:26 +0000472- PyRange_New() now raises ValueError if the fourth argument is not 1.
473 This is part of the removal of deprecated features of the xrange
474 object.
475
Guido van Rossum517c7d42002-04-26 02:49:14 +0000476- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
477 coercion if both arguments have the same type but this type has the
478 CHECKTYPES flag set. This is to better support proxies.
479
Neil Schemenauer9344b142002-04-12 23:00:08 +0000480- The type of tp_free has been changed from "void (*)(PyObject *)" to
481 "void (*)(void *)".
482
483- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
484
Guido van Rossum0986d822002-04-08 01:38:42 +0000485- A type can now inherit its metatype from its base type. Previously,
486 when PyType_Ready() was called, if ob_type was found to be NULL, it
487 was always set to &PyType_Type; now it is set to base->ob_type,
488 where base is tp_base, defaulting to &PyObject_Type.
489
490- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
491
Neil Schemenauerc9abc1d2002-05-08 14:14:41 +0000492- The PyCore_* family of APIs have been removed.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000493
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000494- The "u#" parser marker will now pass through Unicode objects as-is
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000495 without going through the buffer API.
496
Martin v. Löwis7198a522002-01-01 19:59:11 +0000497- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
498
Tim Peters10a3bb52001-12-25 19:07:38 +0000499- An old #define of ANY as void has been removed from pyport.h. This
500 hasn't been used since Python's pre-ANSI days, and the #define has
501 been marked as obsolete since then. SF bug 495548 says it created
502 conflicts with other packages, so keeping it around wasn't harmless.
503
Tim Petersaf8446f2001-12-21 21:36:50 +0000504- Because Python's magic number scheme broke on January 1st, we decided
505 to stop Python development. Thanks for all the fish!
506
Tim Petersfb05db22002-03-11 00:24:00 +0000507- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000508 scheme to a new one. See Python/import.c for details.
509
Tim Petersaf8446f2001-12-21 21:36:50 +0000510New platforms
511
Martin v. Löwisf90ae202002-06-11 06:22:31 +0000512- AtheOS is now supported.
513
Andrew MacIntyre161ad0e2002-08-04 07:25:58 +0000514- the EMX runtime environment on OS/2 is now supported.
515
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000516- GNU/Hurd is now supported.
517
Tim Petersaf8446f2001-12-21 21:36:50 +0000518Tests
519
520Windows
521
Tim Peters08e72952002-04-16 20:48:01 +0000522- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
523 of that has been fixed in the installer (disabled Wise's "delete in-
524 use files" uninstall option).
525
Guido van Rossum181e41a2002-04-06 00:23:25 +0000526- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
527
Tim Peters33187922002-04-04 20:02:04 +0000528- The installer now installs Start menu shortcuts under (the local
529 equivalent of) "All Users" when doing an Admin install.
530
Tim Petersfb05db22002-03-11 00:24:00 +0000531- file.truncate([newsize]) now works on Windows for all newsize values.
532 It used to fail if newsize didn't fit in 32 bits, reflecting a
533 limitation of MS _chsize (which is no longer used).
534
Tim Petersab034fa2002-02-01 11:27:43 +0000535- os.waitpid() is now implemented for Windows, and can be used to block
536 until a specified process exits. This is similar to, but not exactly
537 the same as, os.waitpid() on POSIX systems. If you're waiting for
538 a specific process whose pid was obtained from one of the spawn()
539 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000540 See the docs for details. The docs were changed to clarify that
541 spawn functions return, and waitpid requires, a process handle on
542 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000543
Tim Peters11bd9942002-02-01 00:52:29 +0000544- New tempfile.TemporaryFile implementation for Windows: this doesn't
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000545 need a TemporaryFileWrapper wrapper anymore, and should be immune
Tim Peters11bd9942002-02-01 00:52:29 +0000546 to a nasty problem: before 2.3, if you got a temp file on Windows, it
547 got wrapped in an object whose close() method first closed the
548 underlying file, then deleted the file. This usually worked fine.
549 However, the spawn family of functions on Windows create (at a low C
550 level) the same set of open files in the spawned process Q as were
551 open in the spawning process P. If a temp file f was among them, then
552 doing f.close() in P first closed P's C-level file handle on f, but Q's
553 C-level file handle on f remained open, so the attempt in P to delete f
554 blew up with a "Permission denied" error (Windows doesn't allow
555 deleting open files). This was surprising, subtle, and difficult to
556 work around.
557
558- The os module now exports all the symbolic constants usable with the
559 low-level os.open() on Windows: the new constants in 2.3 are
560 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
561 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
562 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
563 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
564 (so specify both if you want both; note that neither is useful unless
565 specified with O_CREAT too).
566
Tim Petersaf8446f2001-12-21 21:36:50 +0000567Mac
568
569
Tim Peters909c0912001-12-14 23:16:18 +0000570What's New in Python 2.2 final?
571Release date: 21-Dec-2001
572===============================
573
574Type/class unification and new-style classes
575
Barry Warsaw52acb492001-12-21 20:04:22 +0000576- pickle.py, cPickle: allow pickling instances of new-style classes
577 with a custom metaclass.
578
Tim Peters909c0912001-12-14 23:16:18 +0000579Core and builtins
580
Barry Warsaw52acb492001-12-21 20:04:22 +0000581- weakref proxy object: when comparing, unwrap both arguments if both
582 are proxies.
583
Tim Peters909c0912001-12-14 23:16:18 +0000584Extension modules
585
Barry Warsaw52acb492001-12-21 20:04:22 +0000586- binascii.b2a_base64(): fix a potential buffer overrun when encoding
587 very short strings.
588
589- cPickle: the obscure "fast" mode was suspected of causing stack
590 overflows on the Mac. Hopefully fixed this by setting the recursion
591 limit much smaller. If the limit is too low (it only affects
592 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
593 when compiling cPickle.c (or in pyconfig.h).
594
Tim Peters909c0912001-12-14 23:16:18 +0000595Library
596
Barry Warsaw52acb492001-12-21 20:04:22 +0000597- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
598 close or delete time).
599
600- rfc822.py: fixed a bug where the address '<>' was converted to None
601 instead of an empty string (also fixes the email.Utils module).
602
603- xmlrpclib.py: version 1.0.0; uses precision for doubles.
604
605- test suite: the pickle and cPickle tests were not executing any code
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000606 when run from the standard regression test.
Barry Warsaw52acb492001-12-21 20:04:22 +0000607
Tim Peters909c0912001-12-14 23:16:18 +0000608Tools/Demos
609
610Build
611
612C API
613
614New platforms
615
616Tests
617
618Windows
619
Barry Warsaw52acb492001-12-21 20:04:22 +0000620- distutils package: fixed broken Windows installers (bdist_wininst).
621
622- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
623 instances are deleted at process exit time.
624
625- socket.py: prevent mysterious warnings when socket instances are
626 deleted at process exit time.
627
628- posixmodule.c: fix a Windows crash with stat() of a filename ending
629 in backslash.
630
Tim Peters909c0912001-12-14 23:16:18 +0000631Mac
632
Barry Warsaw52acb492001-12-21 20:04:22 +0000633- The Carbon toolbox modules have been upgraded to Universal Headers
634 3.4, and experimental CoreGraphics and CarbonEvents modules have
635 been added. All only for framework-enabled MacOSX.
636
Tim Peters909c0912001-12-14 23:16:18 +0000637
Tim Peters6272dfd2001-12-13 19:34:00 +0000638What's New in Python 2.2c1?
639Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000640===========================
641
642Type/class unification and new-style classes
643
Barry Warsaw06557452001-12-14 20:47:12 +0000644- Guido's tutorial introduction to the new type/class features has
645 been extensively updated. See
646
647 http://www.python.org/2.2/descrintro.html
648
649 That remains the primary documentation in this area.
650
Guido van Rossum33bab012001-12-05 22:45:48 +0000651- Fixed a leak: instance variables declared with __slots__ were never
652 deleted!
653
Guido van Rossum4b800852001-12-03 00:54:52 +0000654- The "delete attribute" method of descriptor objects is called
655 __delete__, not __del__. In previous releases, it was mistakenly
656 called __del__, which created an unfortunate overloading condition
657 with finalizers. (The "get attribute" and "set attribute" methods
658 are still called __get__ and __set__, respectively.)
659
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000660- Some subtle issues with the super built-in were fixed:
661
662 (a) When super itself is subclassed, its __get__ method would still
663 return an instance of the base class (i.e., of super).
664
665 (b) super(C, C()).__class__ would return C rather than super. This
666 is confusing. To fix this, I decided to change the semantics of
667 super so that it only applies to code attributes, not to data
668 attributes. After all, overriding data attributes is not
669 supported anyway.
670
671 (c) The __get__ method didn't check whether the argument was an
672 instance of the type used in creation of the super instance.
673
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000674- Previously, hash() of an instance of a subclass of a mutable type
675 (list or dictionary) would return some value, rather than raising
676 TypeError. This has been fixed. Also, directly calling
677 dict.__hash__ and list.__hash__ now raises the same TypeError
678 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000679
Guido van Rossumd331cb52001-12-05 19:46:42 +0000680- New-style objects now support deleting their __dict__. This is for
681 all intents and purposes equivalent to assigning a brand new empty
682 dictionary, but saves space if the object is not used further.
683
Tim Petersb3c9af12001-11-17 00:21:57 +0000684Core and builtins
685
Tim Peters3caca232001-12-06 06:23:26 +0000686- -Qnew now works as documented in PEP 238: when -Qnew is passed on
687 the command line, all occurrences of "/" use true division instead
688 of classic division. See the PEP for details. Note that "all"
689 means all instances in library and 3rd-party modules, as well as in
690 your own code. As the PEP says, -Qnew is intended for use only in
691 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000692 Note that test_coercion.py in the standard Python test suite fails
693 under -Qnew; this is expected, and won't be repaired until true
694 division becomes the default (in the meantime, test_coercion is
695 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000696
Fred Drake6c01e252001-12-14 17:08:12 +0000697- complex() now only allows the first argument to be a string
698 argument, and raises TypeError if either the second arg is a string
699 or if the second arg is specified when the first is a string.
700
Tim Petersb3c9af12001-11-17 00:21:57 +0000701Extension modules
702
Martin v. Löwis560da622001-11-24 09:24:51 +0000703- gc.get_referents was renamed to gc.get_referrers.
704
Tim Petersb3c9af12001-11-17 00:21:57 +0000705Library
706
Tim Peters25059d32001-12-07 20:35:43 +0000707- Functions in the os.spawn() family now release the global interpreter
708 lock around calling the platform spawn. They should always have done
709 this, but did not before 2.2c1. Multithreaded programs calling
710 an os.spawn function with P_WAIT will no longer block all Python threads
711 until the spawned program completes. It's possible that some programs
712 relies on blocking, although more likely by accident than by design.
713
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000714- webbrowser defaults to netscape.exe on OS/2 now.
715
Martin v. Löwis652e1912001-11-25 14:50:56 +0000716- Tix.ResizeHandle exposes detach_widget, hide, and show.
717
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000718- The charset alias windows_1252 has been added.
719
Barry Warsaw06557452001-12-14 20:47:12 +0000720- types.StringTypes is a tuple containing the defined string types;
721 usually this will be (str, unicode), but if Python was compiled
722 without Unicode support it will be just (str,).
723
724- The pulldom and minidom modules were synchronized to PyXML.
725
Tim Petersb3c9af12001-11-17 00:21:57 +0000726Tools/Demos
727
Barry Warsaw06557452001-12-14 20:47:12 +0000728- A new script called Tools/scripts/google.py was added, which fires
729 off a search on Google.
730
Tim Petersb3c9af12001-11-17 00:21:57 +0000731Build
732
Barry Warsaw06557452001-12-14 20:47:12 +0000733- Note that release builds of Python should arrange to define the
734 preprocessor symbol NDEBUG on the command line (or equivalent).
735 In the 2.2 pre-release series we tried to define this by magic in
736 Python.h instead, but it proved to cause problems for extension
737 authors. The Unix, Windows and Mac builds now all define NDEBUG in
738 release builds via cmdline (or equivalent) instead. Ports to
739 other platforms should do likewise.
740
Jack Jansen1999ef42001-12-06 21:47:20 +0000741- It is no longer necessary to use --with-suffix when building on a
742 case-insensitive file system (such as Mac OS X HFS+). In the build
743 directory an extension is used, but not in the installed python.
744
Tim Petersb3c9af12001-11-17 00:21:57 +0000745C API
746
Tim Petersf582b822001-12-11 18:51:08 +0000747- New function PyDict_MergeFromSeq2() exposes the builtin dict
748 constructor's logic for updating a dictionary from an iterable object
749 producing key-value pairs.
750
Tim Peterscffed4b2001-11-29 03:26:37 +0000751- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000752 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000753 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
754 dump core in some bad cases. This has been repaired. As a result,
755 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
756 previously went unchallenged.
757
Tim Petersb3c9af12001-11-17 00:21:57 +0000758New platforms
759
760Tests
761
762Windows
763
764Mac
765
Jack Jansenffa260f2001-12-06 21:14:00 +0000766- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
767 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000768
Barry Warsaw06557452001-12-14 20:47:12 +0000769- Changed logic for finding python home in Mac OS X framework Pythons.
770 Now sys.executable points to the executable again, in stead of to
771 the shared library. The latter is used only for locating the python
772 home.
773
774
Tim Peters84362bc2001-10-19 17:55:30 +0000775What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000776Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000777===========================
778
779Type/class unification and new-style classes
780
Guido van Rossum3d27df02001-11-15 20:27:54 +0000781- Multiple inheritance mixing new-style and classic classes in the
782 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000783
784 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000785 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000786
787 The MRO (method resolution order) for each base class is respected
788 according to its kind, but the MRO for the derived class is computed
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000789 using new-style MRO rules if any base class is a new-style class.
Tim Peters76f7fe32001-11-15 20:02:21 +0000790 This needs to be documented.
791
Tim Petersa427a2b2001-10-29 22:25:45 +0000792- The new builtin dictionary() constructor, and dictionary type, have
793 been renamed to dict. This reflects a decade of common usage.
794
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000795- dict() now accepts an iterable object producing 2-sequences. For
796 example, dict(d.items()) == d for any dictionary d. The argument,
797 and the elements of the argument, can be any iterable objects.
798
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000799- New-style classes can now have a __del__ method, which is called
800 when the instance is deleted (just like for classic classes).
801
Guido van Rossum12d955c2001-10-26 14:56:06 +0000802- Assignment to object.__dict__ is now possible, for objects that are
803 instances of new-style classes that have a __dict__ (unless the base
804 class forbids it).
805
Guido van Rossumc8e56452001-10-22 00:43:43 +0000806- Methods of built-in types now properly check for keyword arguments
807 (formerly these were silently ignored). The only built-in methods
808 that take keyword arguments are __call__, __init__ and __new__.
809
Guido van Rossum86443212001-10-27 22:28:54 +0000810- The socket function has been converted to a type; see below.
811
Tim Peters84362bc2001-10-19 17:55:30 +0000812Core and builtins
813
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000814- Assignment to __debug__ raises SyntaxError at compile-time. This
815 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000816 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000817
Guido van Rossum12d955c2001-10-26 14:56:06 +0000818- Clarified the error messages for unsupported operands to an operator
819 (like 1 + '').
820
Tim Peters84362bc2001-10-19 17:55:30 +0000821Extension modules
822
Tim Peters5ebfd362001-11-13 23:11:19 +0000823- mmap has a new keyword argument, "access", allowing a uniform way for
824 both Windows and Unix users to create read-only, write-through and
825 copy-on-write memory mappings. This was previously possible only on
826 Unix. A new keyword argument was required to support this in a
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000827 uniform way because the mmap() signatures had diverged across
Tim Peters5ebfd362001-11-13 23:11:19 +0000828 platforms. Thanks to Jay T Miller for repairing this!
829
Tim Peters169ded02001-11-03 19:57:21 +0000830- By default, the gc.garbage list now contains only those instances in
831 unreachable cycles that have __del__ methods; in 2.1 it contained all
832 instances in unreachable cycles. "Instances" here has been generalized
833 to include instances of both new-style and old-style classes.
834
Guido van Rossum12d955c2001-10-26 14:56:06 +0000835- The socket module defines a new method for socket objects,
836 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000837 send() until all data has been sent. Also, the socket function has
838 been converted to a subclassable type, like list and tuple (etc.)
839 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000840
841- Various bugfixes to the curses module. There is now a test suite
842 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000843
Guido van Rossum692adf12001-10-30 03:03:03 +0000844- binascii.b2a_base64 no longer places an arbitrary restriction of 57
845 bytes on its input.
846
Tim Peters84362bc2001-10-19 17:55:30 +0000847Library
848
Tim Peters5ebfd362001-11-13 23:11:19 +0000849- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000850 convenience function.
851
Tim Peters75335872001-11-03 19:35:43 +0000852- Symbolic group names in regular expressions must be unique. For
853 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
854 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000855 Python 2.2 detects this error at regexp compilation time;
856 previously, the error went undetected, and results were
857 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
858 pattern.subn() methods have been rewritten in C. Also, an
859 experimental function/method finditer() has been added, which works
860 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000861
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000862- Tix exposes more commands through the classes DirSelectBox,
863 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
864 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
865 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
866
Tim Peters98791af2001-10-23 01:59:54 +0000867- Traceback objects are now scanned by cyclic garbage collection, so
868 cycles created by casual use of sys.exc_info() no longer cause
869 permanent memory leaks (provided garbage collection is enabled).
870
Guido van Rossum49192142001-10-24 20:51:44 +0000871- os.extsep -- a new variable needed by the RISCOS support. It is the
872 separator used by extensions, and is '.' on all platforms except
873 RISCOS, where it is '/'. There is no need to use this variable
874 unless you have a masochistic desire to port your code to RISCOS.
875
Barry Warsaw012852b2001-11-16 16:17:27 +0000876- mimetypes.py has optional support for non-standard, but commonly
877 found types. guess_type() and guess_extension() now accept an
878 optional `strict' flag, defaulting to true, which controls whether
879 recognize non-standard types or not. A few non-standard types we
880 know about have been added. Also, when run as a script, there are
881 new -l and -e options.
882
883- statcache is now deprecated.
884
885- email.Utils.formatdate() now produces the preferred RFC 2822 style
886 dates with numeric timezones (it used to produce obsolete dates
887 hard coded to "GMT" timezone). An optional `localtime' flag is
888 added to produce dates in the local timezone, with daylight savings
889 time properly taken into account.
890
891- In pickle and cPickle, instead of masking errors in load() by
892 transforming them into SystemError, we let the original exception
893 propagate out. Also, implement support for __safe_for_unpickling__
894 in pickle, as it already was supported in cPickle.
895
Tim Peters84362bc2001-10-19 17:55:30 +0000896Tools/Demos
897
898Build
899
Barry Warsaw012852b2001-11-16 16:17:27 +0000900- The dbm module is built using libdb1 if available. The bsddb module
901 is built with libdb3 if available.
902
903- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
904
Tim Peters84362bc2001-10-19 17:55:30 +0000905C API
906
Tim Peters1fc240e2001-10-26 05:06:50 +0000907- New function PySequence_Fast_GET_SIZE() returns the size of a non-
908 NULL result from PySequence_Fast(), more quickly than calling
909 PySequence_Size().
910
Barry Warsaw012852b2001-11-16 16:17:27 +0000911- New argument unpacking function PyArg_UnpackTuple() added.
912
913- New functions PyObject_CallFunctionObjArgs() and
914 PyObject_CallMethodObjArgs() have been added to make it more
915 convenient and efficient to call functions and methods from C.
916
917- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
918 possible that this will propagate errors it didn't before.
919
920- New function PyObject_CheckReadBuffer(), which returns true if its
921 argument supports the single-segment readable buffer interface.
922
Tim Peters84362bc2001-10-19 17:55:30 +0000923New platforms
924
Guido van Rossum86443212001-10-27 22:28:54 +0000925- We've finally confirmed that this release builds on HP-UX 11.00,
926 *with* threads, and passes the test suite.
927
Tim Peters7a33d8b2001-11-05 02:51:07 +0000928- Thanks to a series of patches from Michael Muller, Python may build
929 again under OS/2 Visual Age C++.
930
Guido van Rossum49192142001-10-24 20:51:44 +0000931- Updated RISCOS port by Dietmar Schwertberger.
932
Tim Peters84362bc2001-10-19 17:55:30 +0000933Tests
934
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000935- Added a test script for the curses module. It isn't run automatically;
936 regrtest.py must be run with '-u curses' to enable it.
937
Tim Peters84362bc2001-10-19 17:55:30 +0000938Windows
939
Barry Warsaw012852b2001-11-16 16:17:27 +0000940Mac
941
942- PythonScript has been moved to unsupported and is slated to be
943 removed completely in the next release.
944
945- It should now be possible to build applets that work on both OS9 and
946 OSX.
947
948- The core is now linked with CoreServices not Carbon; as a side
949 result, default 8bit encoding on OSX is now ASCII.
950
951- Python should now build on OSX 10.1.1
952
Tim Peters84362bc2001-10-19 17:55:30 +0000953
Tim Petersabf925f2001-09-28 21:53:42 +0000954What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000955Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000956===========================
957
958Type/class unification and new-style classes
959
Guido van Rossum687ae002001-10-15 22:03:32 +0000960- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000961 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000962 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000963 remains: the __dict__ of a new-style class is a read-only proxy; you
964 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000965 __defined__ attribute of new-style types no longer exists, for lack
966 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000967 future a __cache__ may be resurrected with a similar function, if I
968 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000969
Tim Peters1c9ca872001-10-04 06:43:12 +0000970- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
971 always returned None, even when there was a class docstring).
972
973- doctest now finds and runs docstrings attached to new-style classes,
974 class methods, static methods, and properties.
975
Guido van Rossum9074ef62001-10-16 21:34:49 +0000976Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000977
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000978- A very subtle syntactical pitfall in list comprehensions was fixed.
979 For example: [a+b for a in 'abc', for b in 'def']. The comma in
980 this example is a mistake. Previously, this would silently let 'a'
981 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
982 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
983 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
984 Note that [a for a in <singleton>] is a convoluted way to say
985 [<singleton>] anyway, so it's not like any expressiveness is lost.
986
Guido van Rossum9074ef62001-10-16 21:34:49 +0000987- getattr(obj, name, default) now only catches AttributeError, as
988 documented, rather than returning the default value for all
989 exceptions (which could mask bugs in a __getattr__ hook, for
990 example).
991
Fred Drakecb7a6b52001-10-22 18:41:51 +0000992- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000993 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000994 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000995 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000996
Guido van Rossum1c486092001-10-19 02:05:35 +0000997- unicode(obj) now behaves more like str(obj), accepting arbitrary
998 objects, and calling a __unicode__ method if it exists.
999 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +00001000 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +00001001
Barry Warsawf6fb1712001-10-19 05:35:40 +00001002- isinstance() now allows any object as the first argument and a
1003 class, a type or something with a __bases__ tuple attribute for the
1004 second argument. The second argument may also be a tuple of a
1005 class, type, or something with __bases__, in which case isinstance()
1006 will return true if the first argument is an instance of any of the
1007 things contained in the second argument tuple. E.g.
1008
1009 isinstance(x, (A, B))
1010
1011 returns true if x is an instance of A or B.
1012
Guido van Rossum9074ef62001-10-16 21:34:49 +00001013Extension modules
1014
1015- thread.start_new_thread() now returns the thread ID (previously None).
1016
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001017- binascii has now two quopri support functions, a2b_qp and b2a_qp.
1018
Guido van Rossumc524d952001-10-19 01:31:59 +00001019- readline now supports setting the startup_hook and the
1020 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +00001021
Guido van Rossumc524d952001-10-19 01:31:59 +00001022- os and posix supports chroot(), setgroups() and unsetenv() where
1023 available. The stat(), fstat(), statvfs() and fstatvfs() functions
1024 now return "pseudo-sequences" -- the various fields can now be
1025 accessed as attributes (e.g. os.stat("/").st_mtime) but for
1026 backwards compatibility they also behave as a fixed-length sequence.
1027 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +00001028 attributes.
1029
1030- time: localtime(), gmtime() and strptime() now return a
1031 pseudo-sequence similar to the os.stat() return value, with
1032 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +00001033
Guido van Rossum9074ef62001-10-16 21:34:49 +00001034- Decompression objects in the zlib module now accept an optional
1035 second parameter to decompress() that specifies the maximum amount
1036 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +00001037
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001038- optional SSL support in the socket module now exports OpenSSL
1039 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
1040 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +00001041 automatically seed its PRNG. Also, the keyfile and certfile
1042 arguments to socket.ssl() are now optional.
1043
1044- posixmodule (and by extension, the os module on POSIX platforms) now
1045 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001046
Guido van Rossum9074ef62001-10-16 21:34:49 +00001047Library
Guido van Rossum3c288632001-10-16 21:13:49 +00001048
Tim Peters7402f792001-10-02 03:53:41 +00001049- doctest now excludes functions and classes not defined by the module
1050 being tested, thanks to Tim Hochberg.
1051
Fred Drakecb7a6b52001-10-22 18:41:51 +00001052- HotShot, a new profiler implemented using a C-based callback, has
1053 been added. This substantially reduces the overhead of profiling,
1054 but it is still quite preliminary. Support modules and
1055 documentation will be added in upcoming releases (before 2.2 final).
1056
Guido van Rossumc4b09b42001-10-04 10:19:00 +00001057- profile now produces correct output in situations where an exception
1058 raised in Python is cleared by C code (e.g. hasattr()). This used
1059 to cause wrong output, including spurious claims of recursive
1060 functions and attribution of time spent to the wrong function.
1061
Tim Peters0a1fc4e2001-10-07 03:12:08 +00001062 The code and documentation for the derived OldProfile and HotProfile
1063 profiling classes was removed. The code hasn't worked for years (if
1064 you tried to use them, they raised exceptions). OldProfile
1065 intended to reproduce the behavior of the profiler Python used more
1066 than 7 years ago, and isn't interesting anymore. HotProfile intended
1067 to provide a faster profiler (but producing less information), and
1068 that's a worthy goal we intend to meet via a different approach (but
1069 without losing information).
1070
Tim Peterscce092d2001-10-09 05:31:56 +00001071- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +00001072 a much better system-specific calibration constant. The constant can
1073 now be specified in an instance constructor, or as a Profile class or
1074 instance variable, instead of by editing profile.py's source code.
1075 Calibration must still be done manually (see the docs for the profile
1076 module).
1077
1078 Note that Profile.calibrate() must be overriden by subclasses.
1079 Improving the accuracy required exploiting detailed knowledge of
1080 profiler internals; the earlier method abstracted away the details
1081 and measured a simplified model instead, but consequently computed
1082 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +00001083
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001084- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +00001085 which indicates whether output is intended for the header 'Q'
1086 encoding.
1087
Guido van Rossuma5343cc2001-10-18 18:02:07 +00001088- The SocketServer.ThreadingMixIn class now closes the request after
1089 finish_request() returns. (Not when it errors out though.)
1090
Barry Warsawf6fb1712001-10-19 05:35:40 +00001091- The nntplib module's NNTP.body() method has grown a `file' argument
1092 to allow saving the message body to a file.
1093
1094- The email package has added a class email.Parser.HeaderParser which
1095 only parses headers and does not recurse into the message's body.
1096 Also, the module/class MIMEAudio has been added for representing
1097 audio data (contributed by Anthony Baxter).
1098
1099- ftplib should be able to handle files > 2GB.
1100
1101- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
1102 ON, and OFF.
1103
Fred Drakecb7a6b52001-10-22 18:41:51 +00001104- xml.dom.minidom NodeList objects now support the length attribute
1105 and item() method as required by the DOM specifications.
1106
Guido van Rossumed554f62001-10-02 23:15:37 +00001107Tools/Demos
1108
1109- Demo/dns was removed. It no longer serves any purpose; a package
1110 derived from it is now maintained by Anthony Baxter, see
1111 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +00001112
Barry Warsawf6fb1712001-10-19 05:35:40 +00001113- The freeze tool has been made more robust, and two new options have
1114 been added: -X and -E.
1115
Tim Petersabf925f2001-09-28 21:53:42 +00001116Build
1117
Barry Warsawf6fb1712001-10-19 05:35:40 +00001118- configure will use CXX in LINKCC if CXX is used to build main() and
1119 the system requires to link a C++ main using the C++ compiler.
1120
Tim Petersabf925f2001-09-28 21:53:42 +00001121C API
1122
Guido van Rossum6c4bce32001-10-18 19:20:25 +00001123- The documentation for the tp_compare slot is updated to require that
1124 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
1125 not correct. This is not yet enforced but will be enforced in
1126 Python 2.3; even later, we may use -2 to indicate errors and +2 for
1127 "NotImplemented". Right now, -1 should be used for an error return.
1128
Tim Petersd38b1c72001-09-30 05:09:37 +00001129- PyLong_AsLongLong() now accepts int (as well as long) arguments.
1130 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
1131 as long) arguments.
1132
Guido van Rossum3c288632001-10-16 21:13:49 +00001133- PyThread_start_new_thread() now returns a long int giving the thread
1134 ID, if one can be calculated; it returns -1 for error, 0 if no
1135 thread ID is calculated (this is an incompatible change, but only
1136 the thread module used this API). This code has only really been
1137 tested on Linux and Windows; other platforms please beware (and
1138 report any bugs or strange behavior).
1139
Guido van Rossum1c486092001-10-19 02:05:35 +00001140- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
1141 input.
1142
Tim Petersabf925f2001-09-28 21:53:42 +00001143New platforms
1144
1145Tests
1146
1147Windows
1148
Tim Peters04cf1d32001-10-09 22:39:40 +00001149- Installer: If you install IDLE, and don't disable file-extension
1150 registration, a new "Edit with IDLE" context (right-click) menu entry
1151 is created for .py and .pyw files.
1152
Tim Peters1ce3cf72001-10-01 17:58:40 +00001153- The signal module now supports SIGBREAK on Windows, thanks to Steven
1154 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
1155 action remains to call Win32 ExitProcess(). This can be changed via
1156 signal.signal(). For example:
1157
1158 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
1159 # (SIGINT) behavior.
1160 import signal
1161 signal.signal(signal.SIGBREAK,
1162 signal.default_int_handler)
1163
1164 try:
1165 while 1:
1166 pass
1167 except KeyboardInterrupt:
1168 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
1169 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
1170 # program without the possibility for any Python-level cleanup).
1171 print "Clean exit"
1172
Tim Petersabf925f2001-09-28 21:53:42 +00001173
Tim Petersb07352e2001-09-08 01:25:47 +00001174What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001175Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +00001176===========================
1177
Guido van Rossum808eea72001-09-25 04:15:41 +00001178Type/class unification and new-style classes
1179
1180- pydoc and inspect are now aware of new-style classes;
1181 e.g. help(list) at the interactive prompt now shows proper
1182 documentation for all operations on list objects.
1183
1184- Applications using Jim Fulton's ExtensionClass module can now safely
1185 be used with Python 2.2. In particular, Zope 2.4.1 now works with
1186 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
1187 examples also work again. It is hoped that Gtk and Boost also work
1188 with 2.2a4 and beyond. (If you can confirm this, please write
1189 webmaster@python.org; if there are still problems, please open a bug
1190 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +00001191
Tim Peters66c1a522001-09-24 21:17:50 +00001192- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001193 These map to read-only attributes 'fget', 'fset', 'fdel', and '__doc__'
Tim Peters66c1a522001-09-24 21:17:50 +00001194 in the constructed property object. fget, fset and fdel weren't
1195 discoverable from Python in 2.2a3. __doc__ is new, and allows to
1196 associate a docstring with a property.
1197
Guido van Rossum808eea72001-09-25 04:15:41 +00001198- Comparison overloading is now more completely implemented. For
1199 example, a str subclass instance can properly be compared to a str
1200 instance, and it can properly overload comparison. Ditto for most
1201 other built-in object types.
1202
1203- The repr() of new-style classes has changed; instead of <type
1204 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
1205 *except* for built-in types, which are still rendered as <type
1206 'Foo'> (to avoid upsetting existing code that might parse or
1207 otherwise rely on repr() of certain type objects).
1208
1209- The repr() of new-style objects is now always <Foo object at XXX>;
1210 previously, it was sometimes <Foo instance at XXX>.
1211
1212- For new-style classes, what was previously called __getattr__ is now
1213 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001214 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +00001215 one in classic classes is defined which is called only if regular
1216 attribute access raises AttributeError; to catch *all* attribute
1217 access, you can use __getattribute__ (for new-style classes). If
1218 both are defined, __getattribute__ is called first, and if it raises
1219 AttributeError, __getattr__ is called.
1220
1221- The __class__ attribute of new-style objects can be assigned to.
1222 The new class must have the same C-level object layout as the old
1223 class.
1224
1225- The builtin file type can be subclassed now. In the usual pattern,
1226 "file" is the name of the builtin type, and file() is a new builtin
1227 constructor, with the same signature as the builtin open() function.
1228 file() is now the preferred way to open a file.
1229
1230- Previously, __new__ would only see sequential arguments passed to
1231 the type in a constructor call; __init__ would see both sequential
1232 and keyword arguments. This made no sense whatsoever any more, so
1233 now both __new__ and __init__ see all arguments.
1234
1235- Previously, hash() applied to an instance of a subclass of str or
1236 unicode always returned 0. This has been repaired.
1237
1238- Previously, an operation on an instance of a subclass of an
1239 immutable type (int, long, float, complex, tuple, str, unicode),
1240 where the subtype didn't override the operation (and so the
1241 operation was handled by the builtin type), could return that
1242 instance instead a value of the base type. For example, if s was of
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001243 a str subclass type, s[:] returned s as-is. Now it returns a str
Guido van Rossum808eea72001-09-25 04:15:41 +00001244 with the same value as s.
1245
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001246- Provisional support for pickling new-style objects has been added.
1247
Guido van Rossum808eea72001-09-25 04:15:41 +00001248Core
1249
Tim Peters2c9aa5e2001-09-23 04:06:05 +00001250- file.writelines() now accepts any iterable object producing strings.
1251
Marc-André Lemburgaefd7662001-09-20 12:59:37 +00001252- PyUnicode_FromEncodedObject() now works very much like
1253 PyObject_Str(obj) in that it tries to use __str__/tp_str
1254 on the object if the object is not a string or buffer. This
1255 makes unicode() behave like str() when applied to non-string/buffer
1256 objects.
1257
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001258- PyFile_WriteObject now passes Unicode objects to the file's write
1259 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +00001260 of a print statement must support Unicode objects, i.e. they must
1261 at least convert them into ASCII strings.
1262
Guido van Rossum624c8af2001-09-18 15:21:04 +00001263- Thread scheduling on Solaris should be improved; it is no longer
1264 necessary to insert a small sleep at the start of a thread in order
1265 to let other runnable threads be scheduled.
1266
Tim Petersb07352e2001-09-08 01:25:47 +00001267Library
1268
Marc-André Lemburgbf990172001-09-27 14:17:33 +00001269- StringIO.StringIO instances and cStringIO.StringIO instances support
1270 read character buffer compatible objects for their .write() methods.
1271 These objects are converted to strings and then handled as such
1272 by the instances.
1273
Barry Warsaw2f600732001-09-24 04:28:10 +00001274- The "email" package has been added. This is basically a port of the
1275 mimelib package <http://sf.net/projects/mimelib> with API changes
1276 and some implementations updated to use iterators and generators.
1277
Tim Peters8a9c2842001-09-22 21:30:22 +00001278- difflib.ndiff() and difflib.Differ.compare() are generators now. This
1279 restores the ability of Tools/scripts/ndiff.py to start producing output
1280 before the entire comparison is complete.
1281
Barry Warsaw58b072d2001-09-22 04:44:21 +00001282- StringIO.StringIO instances and cStringIO.StringIO instances support
1283 iteration just like file objects (i.e. their .readline() method is
1284 called for each iteration until it returns an empty string).
1285
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +00001286- The codecs module has grown four new helper APIs to access
1287 builtin codecs: getencoder(), getdecoder(), getreader(),
1288 getwriter().
1289
Guido van Rossum624c8af2001-09-18 15:21:04 +00001290- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
1291 simplifies writing XML RPC servers.
1292
Barry Warsaw647d5e82001-09-28 17:01:02 +00001293- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +00001294 after interpretation of symbolic links. On non-Unix systems, this
1295 is an alias for os.path.abspath().
1296
Tim Peters16a77ad2001-09-08 04:00:12 +00001297- operator.indexOf() (PySequence_Index() in the C API) now works with any
1298 iterable object.
1299
Guido van Rossum624c8af2001-09-18 15:21:04 +00001300- smtplib now supports various authentication and security features of
1301 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001302
Guido van Rossum624c8af2001-09-18 15:21:04 +00001303- hmac: a new module implementing keyed hashing for message
1304 authentication.
1305
1306- mimetypes now recognizes more extensions and file types. At the
1307 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001308
Guido van Rossum624c8af2001-09-18 15:21:04 +00001309- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001310 Python 2.2 bytecode generation. It has also been promoted from a
1311 Tool to a standard library package. (Tools/compiler still exists as
1312 a sample driver.)
1313
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001314Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +00001315
Tim Petersb07352e2001-09-08 01:25:47 +00001316Build
1317
Guido van Rossum624c8af2001-09-18 15:21:04 +00001318- Large file support (LFS) is now automatic when the platform supports
1319 it; no more manual configuration tweaks are needed. On Linux, at
1320 least, it's possible to have a system whose C library supports large
1321 files but whose kernel doesn't; in this case, large file support is
1322 still enabled but doesn't do you any good unless you upgrade your
1323 kernel or share your Python executable with another system whose
1324 kernel has large file support.
1325
1326- The configure script now supplies plausible defaults in a
1327 cross-compilation environment. This doesn't mean that the supplied
1328 values are always correct, or that cross-compilation now works
1329 flawlessly -- but it's a first step (and it shuts up most of
1330 autoconf's warnings about AC_TRY_RUN).
1331
1332- The Unix build is now a bit less chatty, courtesy of the parser
1333 generator. The build is completely silent (except for errors) when
1334 using "make -s", thanks to a -q option to setup.py.
1335
Tim Petersb07352e2001-09-08 01:25:47 +00001336C API
1337
Guido van Rossum624c8af2001-09-18 15:21:04 +00001338- The "structmember" API now supports some new flag bits to deny read
1339 and/or write access to attributes in restricted execution mode.
1340
Tim Petersb07352e2001-09-08 01:25:47 +00001341New platforms
1342
Guido van Rossum624c8af2001-09-18 15:21:04 +00001343- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1344 (http://familiar.handhelds.org).
1345
Tim Petersb07352e2001-09-08 01:25:47 +00001346Tests
1347
Tim Peters8a9c2842001-09-22 21:30:22 +00001348- The "classic" standard tests, which work by comparing stdout to
1349 an expected-output file under Lib/test/output/, no longer stop at
1350 the first mismatch. Instead the test is run to completion, and a
1351 variant of ndiff-style comparison is used to report all differences.
1352 This is much easier to understand than the previous style of reporting.
1353
1354- The unittest-based standard tests now use regrtest's test_main()
1355 convention, instead of running as a side-effect of merely being
1356 imported. This allows these tests to be run in more natural and
1357 flexible ways as unittests, outside the regrtest framework.
1358
1359- regrtest.py is much better integrated with unittest and doctest now,
1360 especially in regard to reporting errors.
1361
Tim Petersb07352e2001-09-08 01:25:47 +00001362Windows
1363
Guido van Rossum624c8af2001-09-18 15:21:04 +00001364- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001365 that support it (NTFS under Windows 2000). See "What's New in
1366 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001367
Tim Petersb07352e2001-09-08 01:25:47 +00001368
Tim Petersedc99312001-08-22 21:36:50 +00001369What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001370Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001371===========================
1372
1373Core
1374
Tim Peters9fffa3e2001-09-04 05:14:19 +00001375- Conversion of long to float now raises OverflowError if the long is too
1376 big to represent as a C double.
1377
Tim Peters32f453e2001-09-03 08:35:41 +00001378- The 3-argument builtin pow() no longer allows a third non-None argument
1379 if either of the first two arguments is a float, or if both are of
1380 integer types and the second argument is negative (in which latter case
1381 the arguments are converted to float, so this is really the same
1382 restriction).
1383
Tim Peters5d2b77c2001-09-03 05:47:38 +00001384- The builtin dir() now returns more information, and sometimes much
1385 more, generally naming all attributes of an object, and all attributes
1386 reachable from the object via its class, and from its class's base
1387 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1388 an empty list. In 2.2a3,
1389
1390 >>> dir([])
1391 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1392 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1393 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1394 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1395 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1396 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1397 'reverse', 'sort']
1398
1399 dir(module) continues to return only the module's attributes, though.
1400
Tim Petersbdee63f2001-09-02 03:40:59 +00001401- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001402 than raising OverflowError. This is a partial implementation of PEP
1403 237. You can use -Wdefault::OverflowWarning to enable a warning for
1404 this situation, and -Werror::OverflowWarning to revert to the old
1405 OverflowError exception.
1406
Guido van Rossum61c345f2001-09-04 03:26:15 +00001407- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001408 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001409 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1410 -Qold, meaning the / operator has its classic meaning and no
1411 warnings are issued. Using -Qwarn issues a run-time warning about
1412 all uses of classic division for int and long arguments; -Qwarnall
1413 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001414 (for use with fixdiv.py).
1415 [Note: the remainder of this paragraph (preserved below) became
1416 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1417 <obsolete>
1418 Using -Qnew is questionable; it turns on new division by default, but
1419 only in the __main__ module. You can usefully combine -Qwarn or
1420 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1421 warns about classic division everywhere else.
1422 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001423
Tim Petersbdee63f2001-09-02 03:40:59 +00001424- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001425 long, float, str, unicode, and tuple. (The types complex, list and
1426 dictionary can also be subclassed; this was introduced earlier.)
1427 Note that restrictions apply when subclassing immutable built-in
1428 types: you can only affect the value of the instance by overloading
1429 __new__. You can add mutable attributes, and the subclass instances
1430 will have a __dict__ attribute, but you cannot change the "value"
1431 (as implemented by the base class) of an immutable subclass instance
1432 once it is created.
1433
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001434- The dictionary constructor now takes an optional argument, a
1435 mapping-like object, and initializes the dictionary from its
1436 (key, value) pairs.
1437
Tim Petersbdee63f2001-09-02 03:40:59 +00001438- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001439 "cooperative super calls" in a multiple inheritance setting. For an
1440 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1441
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001442- A new built-in type, property, has been added. This enables the
1443 creation of "properties". These are attributes implemented by
1444 getter and setter functions (or only one of these for read-only or
1445 write-only attributes), without the need to override __getattr__.
1446 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001447
Tim Petersbdee63f2001-09-02 03:40:59 +00001448- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001449 liberalized, to allow leading zeroes. Examples of literals now
1450 legal that were SyntaxErrors before:
1451
1452 00.0 0e3 0100j 07.5 00000000000000000008.
1453
Tim Petersbdee63f2001-09-02 03:40:59 +00001454- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001455 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1456
Tim Petersedc99312001-08-22 21:36:50 +00001457Library
1458
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001459- telnetlib includes symbolic names for the options, and support for
1460 setting an option negotiation callback.
1461
Tim Petersa40c7932001-09-05 22:36:56 +00001462- The new C standard no longer requires that math libraries set errno to
1463 ERANGE on overflow. For platform libraries that exploit this new
1464 freedom, Python's overflow-checking was wholly broken. A new overflow-
1465 checking scheme attempts to repair that, but may not be reliable on all
1466 platforms (C doesn't seem to provide anything both useful and portable
1467 in this area anymore).
1468
Martin v. Löwis44f86962001-09-05 13:44:54 +00001469- Asynchronous timeout actions are available through the new class
1470 threading.Timer.
1471
Tim Peters78526162001-09-05 00:53:45 +00001472- math.log and math.log10 now return sensible results for even huge
1473 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1474
Tim Petersbdee63f2001-09-02 03:40:59 +00001475- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001476 currently held. See the docs for the imp module.
1477
Tim Petersbdee63f2001-09-02 03:40:59 +00001478- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001479 dumps containing ints written on platforms where Python ints are 8 bytes.
1480 When read on a box where Python ints are 4 bytes, such values are
1481 converted to Python longs.
1482
Tim Petersbdee63f2001-09-02 03:40:59 +00001483- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001484 code objects is no longer allowed. This plugs a security hole.
1485
Steve Purcell6091cd62001-09-06 16:05:17 +00001486- unittest.TestResult instances no longer store references to tracebacks
1487 generated by test failures. This prevents unexpected dangling references
1488 to objects that should be garbage collected between tests.
1489
Tim Petersedc99312001-08-22 21:36:50 +00001490Tools
1491
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001492- Tools/scripts/fixdiv.py has been added which can be used to fix
1493 division operators as per PEP 238.
1494
Tim Petersedc99312001-08-22 21:36:50 +00001495Build
1496
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001497- If you are an adventurous person using Mac OS X you may want to look at
1498 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1499 application, which can be used for experimenting with Carbon or Cocoa.
1500 Discussion of this on pythonmac-sig, please.
1501
Tim Peters7eea37e2001-09-04 22:08:56 +00001502C API
1503
1504- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001505
Tim Peters9fffa3e2001-09-04 05:14:19 +00001506- Note that PyLong_AsDouble can fail! This has always been true, but no
1507 callers checked for it. It's more likely to fail now, because overflow
1508 errors are properly detected now. The proper way to check:
1509
1510 double x = PyLong_AsDouble(some_long_object);
1511 if (x == -1.0 && PyErr_Occurred()) {
1512 /* The conversion failed. */
1513 }
1514
Tim Petersbdee63f2001-09-02 03:40:59 +00001515- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001516 compile but will not participate in GC. To upgrade an extension
1517 module:
1518
1519 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001520
Neil Schemenauer4042c692001-08-30 15:38:01 +00001521 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1522 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001523
Neil Schemenauer4042c692001-08-30 15:38:01 +00001524 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1525 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001526
Neil Schemenauer4042c692001-08-30 15:38:01 +00001527 - remove PyGC_HEAD_SIZE from object size calculations
1528
1529 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1530
Tim Petersbdee63f2001-09-02 03:40:59 +00001531- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001532 These can be used safely to construct string objects from a
1533 sprintf-style format string (similar to the format string supported
1534 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001535
Tim Petersedc99312001-08-22 21:36:50 +00001536New platforms
1537
Tim Petersb7da0902001-09-02 23:01:43 +00001538- Stephen Hansen contributed patches sufficient to get a clean compile
1539 under Borland C (Windows), but he reports problems running it and ran
1540 out of time to complete the port. Volunteers? Expect a MemoryError
1541 when importing the types module; this is probably shallow, and
1542 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001543
Tim Petersedc99312001-08-22 21:36:50 +00001544Tests
1545
1546Windows
1547
Tim Peters6e13a562001-09-06 00:32:15 +00001548- Large file support is now enabled on Win32 platforms as well as on
1549 Win64. This means that, for example, you can use f.tell() and f.seek()
1550 to manipulate files larger than 2 gigabytes (provided you have enough
1551 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001552 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1553 filesize limit, and large file support makes no difference there.
1554 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1555 NTFS has no practical limit on file size, and files of any size can be
1556 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001557
Tim Petersbdee63f2001-09-02 03:40:59 +00001558- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001559 points to command.com (patch from Brian Quinlan).
1560
Tim Petersedc99312001-08-22 21:36:50 +00001561
Tim Peters20f51a72001-07-21 02:31:40 +00001562What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001563Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001564===========================
1565
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001566Build
1567
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001568- Tim Peters developed a brand new Windows installer using Wise 8.1,
1569 generously donated to us by Wise Solutions.
1570
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001571- configure supports a new option --enable-unicode, with the values
1572 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1573 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001574
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001575- A new configure option --enable-framework builds a Mac OS X framework,
1576 which "make frameworkinstall" will install. This provides a starting
1577 point for more mac-like functionality, join pythonmac-sig@python.org
1578 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001579
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001580- The NeXT platform is no longer supported.
1581
1582- The `new' module is now statically linked.
1583
Tim Peters0afb6092001-08-15 06:06:44 +00001584Tools
1585
1586- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001587 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001588 the module docstring for details.
1589
Tim Peters20f51a72001-07-21 02:31:40 +00001590Tests
1591
Tim Peters5e824c32001-08-12 22:25:01 +00001592- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001593 platforms, allowing to give clearer test result output. regrtest
1594 also has optional --use/-u switch to run normally disabled tests
1595 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001596
Tim Peters20f51a72001-07-21 02:31:40 +00001597- Several new tests in the standard test suite, with special thanks to
1598 Nick Mathewson.
1599
1600Core
1601
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001602- The floor division operator // has been added as outlined in PEP
1603 238. The / operator still provides classic division (and will until
1604 Python 3.0) unless "from __future__ import division" is included, in
1605 which case the / operator will provide true division. The operator
1606 module provides truediv() and floordiv() functions. Augmented
1607 assignment variants are included, as are the equivalent overloadable
1608 methods and C API methods. See the PEP for a full discussion:
1609 <http://python.sf.net/peps/pep-0238.html>
1610
Tim Peters6cd6a822001-08-17 22:11:27 +00001611- Future statements are now effective in simulated interactive shells
1612 (like IDLE). This should "just work" by magic, but read Michael
1613 Hudson's "Future statements in simulated shells" PEP 264 for full
1614 details: <http://python.sf.net/peps/pep-0264.html>.
1615
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001616- The type/class unification (PEP 252-253) was integrated into the
1617 trunk and is not so tentative any more (the exact specification of
1618 some features is still tentative). A lot of work has done on fixing
1619 bugs and adding robustness and features (performance still has to
1620 come a long way).
1621
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001622- Warnings about a mismatch in the Python API during extension import
1623 now use the Python warning framework (which makes it possible to
1624 write filters for these warnings).
1625
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001626- A function's __dict__ (aka func_dict) will now always be a
1627 dictionary. It used to be possible to delete it or set it to None,
1628 but now both actions raise TypeErrors. It is still legal to set it
1629 to a dictionary object. Getting func.__dict__ before any attributes
1630 have been assigned now returns an empty dictionary instead of None.
1631
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001632- A new command line option, -E, was added which disables the use of
1633 all environment variables, or at least those that are specifically
1634 significant to Python. Usually those have a name starting with
1635 "PYTHON". This was used to fix a problem where the tests fail if
1636 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1637 older distribution.
1638
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001639Library
1640
Tim Peters5e824c32001-08-12 22:25:01 +00001641- New class Differ and new functions ndiff() and restore() in difflib.py.
1642 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001643 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001644
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001645- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1646 value using the minimal quoting required for the value; more
1647 reliable than using xml.sax.saxutils.escape() for attribute values.
1648
1649- Readline completion support for cmd.Cmd was added.
1650
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001651- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1652
1653- Added function threading.BoundedSemaphore()
1654
1655- Added Ka-Ping Yee's cgitb.py module.
1656
1657- The `new' module now exposes the CO_xxx flags.
1658
Martin v. Löwis560da622001-11-24 09:24:51 +00001659- The gc module offers the get_referents function.
1660
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001661New platforms
1662
1663C API
1664
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001665- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1666 which provide a cross-platform implementations for the
1667 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1668 the standard sprintf() and vsprintf() C lib APIs, these versions
1669 apply bounds checking on the used buffer which enhances protection
1670 against buffer overruns.
1671
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001672- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001673 and extensions using different Unicode widths is rendered next to
1674 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001675 will result in an ImportError. Unicode extensions writers must make
1676 sure to check the Unicode width compatibility in their extensions by
1677 using at least one of the mangled Unicode APIs in the extension.
1678
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001679- Two new flags METH_NOARGS and METH_O are available in method definition
1680 tables to simplify implementation of methods with no arguments and a
1681 single untyped argument. Calling such methods is more efficient than
1682 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1683 deprecated.
1684
Tim Petersc1731372001-08-04 08:12:36 +00001685Windows
1686
1687- "import module" now compiles module.pyw if it exists and nothing else
1688 relevant is found.
1689
Tim Peters20f51a72001-07-21 02:31:40 +00001690
Guido van Rossum55a78992001-07-17 17:22:32 +00001691What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001692Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001693===========================
1694
1695Core
Tim Petersa814db52001-05-14 07:05:58 +00001696
Tim Peters6d6c1a32001-08-02 04:15:00 +00001697- TENTATIVELY, a large amount of code implementing much of what's
1698 described in PEP 252 (Making Types Look More Like Classes) and PEP
1699 253 (Subtyping Built-in Types) was added. This will be released
1700 with Python 2.2a1. Documentation will be provided separately
1701 through http://www.python.org/2.2/. The purpose of releasing this
1702 with Python 2.2a1 is to test backwards compatibility. It is
1703 possible, though not likely, that a decision is made not to release
1704 this code as part of 2.2 final, if any serious backwards
1705 incompapatibilities are found during alpha testing that cannot be
1706 repaired.
1707
Guido van Rossum55a78992001-07-17 17:22:32 +00001708- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001709 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001710 more 'yield' statements. See PEP 255. Since this adds a new
1711 keyword to the language, this feature must be enabled by including a
1712 future statement: "from __future__ import generators" (see PEP 236).
1713 Generators will become a standard feature in a future release
1714 (probably 2.3). Without this future statement, 'yield' remains an
1715 ordinary identifier, but a warning is issued each time it is used.
1716 (These warnings currently don't conform to the warnings framework of
1717 PEP 230; we intend to fix this in 2.2a2.)
1718
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001719- The UTF-16 codec was modified to be more RFC compliant. It will now
1720 only remove BOM characters at the start of the string and then
1721 only if running in native mode (UTF-16-LE and -BE won't remove a
1722 leading BMO character).
1723
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001724- Strings now have a new method .decode() to complement the already
1725 existing .encode() method. These two methods provide direct access
1726 to the corresponding decoders and encoders of the registered codecs.
1727
1728 To enhance the usability of the .encode() method, the special
1729 casing of Unicode object return values was dropped (Unicode objects
1730 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001731
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001732 Both methods will now return whatever the codec in charge of the
1733 requested encoding returns as object, e.g. Unicode codecs will
1734 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1735 will return u"äöü"). This enables codec writer to create codecs
1736 for various simple to use conversions.
1737
1738 New codecs were added to demonstrate these new features (the .encode()
1739 and .decode() columns indicate the type of the returned objects):
1740
1741 Name | .encode() | .decode() | Description
1742 ----------------------------------------------------------------------
1743 uu | string | string | UU codec (e.g. for email)
1744 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001745 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001746 zlib | string | string | zlib compression
1747 hex | string | string | 2-byte hex codec
1748 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1749
Mark Hammond2a0af792001-05-14 03:09:36 +00001750- Some operating systems now support the concept of a default Unicode
1751 encoding for file system operations. Notably, Windows supports 'mbcs'
1752 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001753 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001754 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001755
1756 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001757 functions that return filenames (such as os.listdir()) to return Python
1758 string objects pre-encoded using the default file system encoding for
1759 the platform. As this encoding is likely to be different from Python's
1760 default encoding, converting this name to a Unicode object before passing
1761 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001762 would attempt to use its default encoding (generally ASCII) rather than
1763 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001764
Tim Petersa814db52001-05-14 07:05:58 +00001765 In general, this change simply removes surprises when working with
1766 Unicode and the file system, making these operations work as you expect,
1767 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001768 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001769
Tim Peters61dff2b2001-05-08 15:43:37 +00001770- Float (and complex) literals in source code were evaluated to full
1771 precision only when running from a .py file; the same code loaded from a
1772 .pyc (or .pyo) file could suffer numeric differences starting at about the
1773 12th significant decimal digit. For example, on a machine with IEEE-754
1774 floating arithmetic,
1775
1776 x = 9007199254740992.0
1777 print long(x)
1778
1779 printed 9007199254740992 if run directly from .py, but 9007199254740000
1780 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1781 str(float) instead of repr(float) when building code objects. marshal
1782 now uses repr(float) instead, which should reproduce floats to full
1783 machine precision (assuming the platform C float<->string I/O conversion
1784 functions are of good quality).
1785
1786 This may cause floating-point results to change in some cases, and
1787 usually for the better, but may also cause numerically unstable
1788 algorithms to break.
1789
Tim Peters2f228e72001-05-13 00:19:31 +00001790- The implementation of dicts suffers fewer collisions, which has speed
1791 benefits. However, the order in which dict entries appear in dict.keys(),
1792 dict.values() and dict.items() may differ from previous releases for a
1793 given dict. Nothing is defined about this order, so no program should
1794 rely on it. Nevertheless, it's easy to write test cases that rely on the
1795 order by accident, typically because of printing the str() or repr() of a
1796 dict to an "expected results" file. See Lib/test/test_support.py's new
1797 sortdict(dict) function for a simple way to display a dict in sorted
1798 order.
1799
Tim Peters7a3bfc32001-06-12 01:22:22 +00001800- Many other small changes to dicts were made, resulting in faster
1801 operation along the most common code paths.
1802
Guido van Rossum10315822001-05-01 20:54:30 +00001803- Dictionary objects now support the "in" operator: "x in dict" means
1804 the same as dict.has_key(x).
1805
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001806- The update() method of dictionaries now accepts generic mapping
1807 objects. Specifically the argument object must support the .keys()
1808 and __getitem__() methods. This allows you to say, for example,
1809 {}.update(UserDict())
1810
Guido van Rossum10315822001-05-01 20:54:30 +00001811- Iterators were added; this is a generalized way of providing values
1812 to a for loop. See PEP 234. There's a new built-in function iter()
1813 to return an iterator. There's a new protocol to get the next value
1814 from an iterator using the next() method (in Python) or the
1815 tp_iternext slot (in C). There's a new protocol to get iterators
1816 using the __iter__() method (in Python) or the tp_iter slot (in C).
1817 Iterating (i.e. a for loop) over a dictionary generates its keys.
1818 Iterating over a file generates its lines.
1819
Tim Petersf553f892001-05-01 20:45:31 +00001820- The following functions were generalized to work nicely with iterator
1821 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001822 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001823 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1824 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001825 join() method of strings
1826 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001827 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1828 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001829 right-hand side of assignment statements with multiple targets, such as
1830 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001831
Tim Petersd85e1022001-05-11 21:51:48 +00001832- Accessing module attributes is significantly faster (for example,
1833 random.random or os.path or yourPythonModule.yourAttribute).
1834
Tim Peterse63415e2001-05-08 04:38:29 +00001835- Comparing dictionary objects via == and != is faster, and now works even
1836 if the keys and values don't support comparisons other than ==.
1837
Tim Peters95bf9392001-05-10 08:32:44 +00001838- Comparing dictionaries in ways other than == and != is slower: there were
1839 insecurities in the dict comparison implementation that could cause Python
1840 to crash if the element comparison routines for the dict keys and/or
1841 values mutated the dicts. Making the code bulletproof slowed it down.
1842
Tim Peterseb28ef22001-06-02 05:27:19 +00001843- Collisions in dicts are resolved via a new approach, which can help
1844 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001845 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001846 faster now. Thanks to Christian Tismer for pointing out the cause and
1847 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001848
Tim Peters52e155e2001-06-16 05:42:57 +00001849- repr() is much faster for large containers (dict, list, tuple).
1850
1851
Tim Petersa814db52001-05-14 07:05:58 +00001852Library
1853
Fred Drake960fdf92001-07-20 18:38:26 +00001854- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1855 were added to the string module. These a locale-indenpendent
1856 constants, unlike letters, lowercase, and uppercase. These are now
1857 use in appropriate locations in the standard library.
1858
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001859- The flags used in dlopen calls can now be configured using
1860 sys.setdlopenflags and queried using sys.getdlopenflags.
1861
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001862- Fredrik Lundh's xmlrpclib is now a standard library module. This
1863 provides full client-side XML-RPC support. In addition,
1864 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1865 one asyncore-based). Thanks to Eric Raymond for the documentation.
1866
Guido van Rossum643d3912001-07-05 14:46:25 +00001867- The xrange() object is simplified: it no longer supports slicing,
1868 repetition, comparisons, efficient 'in' checking, the tolist()
1869 method, or the start, stop and step attributes. See PEP 260.
1870
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001871- A new function fnmatch.filter to filter lists of file names was added.
1872
Barry Warsawffd674d2001-05-22 16:00:10 +00001873- calendar.py uses month and day names based on the current locale.
1874
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001875- strop is now *really* obsolete (this was announced before with 1.6),
1876 and issues DeprecationWarning when used (except for the four items
1877 that are still imported into string.py).
1878
Tim Petersa814db52001-05-14 07:05:58 +00001879- Cookie.py now sorts key+value pairs by key in output strings.
1880
1881- pprint.isrecursive(object) didn't correctly identify recursive objects.
1882 Now it does.
1883
Tim Peters95b3f782001-05-14 18:39:41 +00001884- pprint functions now much faster for large containers (tuple, list, dict).
1885
Tim Peters7b9542a2001-06-10 23:40:19 +00001886- New 'q' and 'Q' format codes in the struct module, corresponding to C
1887 types "long long" and "unsigned long long" (on Windows, __int64). In
1888 native mode, these can be used only when the platform C compiler supports
1889 these types (when HAVE_LONG_LONG is #define'd by the Python config
1890 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001891 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1892 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001893
Guido van Rossum83213cc2001-06-12 16:48:52 +00001894- The site module installs a new built-in function 'help' that invokes
1895 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1896 it displays a message reminding the user to use 'help()' or
1897 'help(object)'.
1898
Tim Petersa814db52001-05-14 07:05:58 +00001899Tests
1900
1901- New test_mutants.py runs dict comparisons where the key and value
1902 comparison operators mutute the dicts randomly during comparison. This
1903 rapidly causes Python to crash under earlier releases (not for the faint
1904 of heart: it can also cause Win9x to freeze or reboot!).
1905
1906- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001907 pprint.isreadable() return sensible results. Also verifies that simple
1908 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001909
Tim Peters4324aa32001-05-28 22:30:08 +00001910C API
1911
1912- Removed the unused last_is_sticky argument from the internal
1913 _PyTuple_Resize(). If this affects you, you were cheating.
1914
1915
Guido van Rossum55a78992001-07-17 17:22:32 +00001916======================================================================
1917
1918
Guido van Rossumffe13be2001-04-16 18:46:45 +00001919What's New in Python 2.1 (final)?
1920=================================
1921
1922We only changed a few things since the last release candidate, all in
1923Python library code:
1924
1925- A bug in the locale module was fixed that affected locales which
1926 define no grouping for numeric formatting.
1927
1928- A few bugs in the weakref module's implementations of weak
1929 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1930 and the test suite was updated to check for these bugs.
1931
1932- An old bug in the os.path.walk() function (introduced in Python
1933 2.0!) was fixed: a non-existent file would cause an exception
1934 instead of being ignored.
1935
1936- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1937 PyChecker.
1938
1939
Guido van Rossum5b08f132001-04-16 02:05:23 +00001940What's New in Python 2.1c2?
1941===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001942
Guido van Rossum5b08f132001-04-16 02:05:23 +00001943A flurry of small changes, and one showstopper fixed in the nick of
1944time made it necessary to release another release candidate. The list
1945here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001946
Guido van Rossum5b08f132001-04-16 02:05:23 +00001947Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001948
Guido van Rossum5b08f132001-04-16 02:05:23 +00001949- Tim discovered a nasty bug in the dictionary code, caused by
1950 PyDict_Next() calling dict_resize(), and the GC code's use of
1951 PyDict_Next() violating an assumption in dict_items(). This was
1952 fixed with considerable amounts of band-aid, but the net effect is a
1953 saner and more robust implementation.
1954
1955- Made a bunch of symbols static that were accidentally global.
1956
1957Build and Ports
1958
1959- The setup.py script didn't check for a new enough version of zlib
1960 (1.1.3 is needed). Now it does.
1961
1962- Changed "make clean" target to also remove shared libraries.
1963
1964- Added a more general warning about the SGI Irix optimizer to README.
1965
1966Library
1967
1968- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1969 omitted the slash between host and file.html.
1970
1971- The mailbox module's _Mailbox class contained a completely broken
1972 and undocumented seek() method. Ripped it out.
1973
1974- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1975 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1976
1977- Fixed a few last-minute bugs in unittest.
1978
1979Extensions
1980
1981- Reverted the patch to the OpenSSL code in socketmodule.c to support
1982 RAND_status() and the EGD, and the subsequent patch that tried to
1983 fix it for pre-0.9.5 versions; the problem with the patch is that on
1984 some systems it issues a warning whenever socket is imported, and
1985 that's unacceptable.
1986
1987Tests
1988
1989- Fixed the pickle tests to work with "import test.test_pickle".
1990
1991- Tweaked test_locale.py to actually run the test Windows.
1992
1993- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1994 not "wb" (which is not a valid mode at all).
1995
1996- Fix pstats browser crashes. Import readline if it exists to make
1997 the user interface nicer.
1998
1999- Add "import thread" to the top of test modules that import the
2000 threading module (test_asynchat and test_threadedtempfile). This
2001 prevents test failures caused by a broken threading module resulting
2002 from a previously caught failed import.
2003
2004- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
2005 needed on some platforms (e.g. Solaris 8) when the tests are run
2006 twice in succession.
2007
2008- Skip rather than fail test_sunaudiodev if no audio device is found.
2009
2010
2011What's New in Python 2.1c1?
2012===========================
2013
2014This list was significantly updated when 2.1c2 was released; the 2.1c1
2015release didn't mention most changes that were actually part of 2.1c1:
2016
2017Legal
2018
2019- Copyright was assigned to the Python Software Foundation (PSF) and a
2020 PSF license (very similar to the CNRI license) was added.
2021
2022- The CNRI copyright notice was updated to include 2001.
2023
2024Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00002025
Guido van Rossumc9932722001-04-12 02:31:27 +00002026- After a public outcry, assignment to __debug__ is no longer illegal;
2027 instead, a warning is issued. It will become illegal in 2.2.
2028
Guido van Rossum5b08f132001-04-16 02:05:23 +00002029- Fixed a core dump with "%#x" % 0, and changed the semantics so that
2030 "%#x" now always prepends "0x", even if the value is zero.
2031
2032- Fixed some nits in the bytecode compiler.
2033
2034- Fixed core dumps when calling certain kinds of non-functions.
2035
2036- Fixed various core dumps caused by reference count bugs.
2037
2038Build and Ports
2039
2040- Use INSTALL_SCRIPT to install script files.
2041
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002042- New port: SCO Unixware 7, by Billy G. Allie.
2043
Guido van Rossum5b08f132001-04-16 02:05:23 +00002044- Updated RISCOS port.
2045
2046- Updated BeOS port and notes.
2047
2048- Various other porting problems resolved.
2049
2050Library
2051
2052- The TERMIOS and SOCKET modules are now truly obsolete and
2053 unnecessary. Their symbols are incorporated in the termios and
2054 socket modules.
2055
2056- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
2057 better tests for pickling.
2058
2059- threading: make Condition.wait() robust against KeyboardInterrupt.
2060
2061- zipfile: add support to zipfile to support opening an archive
2062 represented by an open file rather than a file name. Fix bug where
2063 the archive was not properly closed. Fixed a bug in this bugfix
2064 where flush() was called for a read-only file.
2065
2066- imputil: added an uninstall() method to the ImportManager.
2067
2068- Canvas: fixed bugs in lower() and tkraise() methods.
2069
2070- SocketServer: API change (added overridable close_request() method)
2071 so that the TCP server can explicitly close the request.
2072
2073- pstats: Eric Raymond added a simple interactive statistics browser,
2074 invoked when the module is run as a script.
2075
2076- locale: fixed a problem in format().
2077
2078- webbrowser: made it work when the BROWSER environment variable has a
2079 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
2080 KDE 2. Fixed some other nits.
2081
2082- unittest: changes to allow using a different exception than
2083 AssertionError, and added a few more function aliases. Some other
2084 small changes.
2085
2086- urllib, urllib2: fixed redirect problems and a coupleof other nits.
2087
2088- asynchat: fixed a critical bug in asynchat that slipped through the
2089 2.1b2 release. Fixed another rare bug.
2090
2091- Fix some unqualified except: clauses (always a bad code example).
2092
2093XML
2094
2095- pyexpat: new API get_version_string().
2096
2097- Fixed some minidom bugs.
2098
2099Extensions
2100
2101- Fixed a core dump in _weakref. Removed the weakref.mapping()
2102 function (it adds nothing to the API).
2103
2104- Rationalized the use of header files in the readline module, to make
2105 it compile (albeit with some warnings) with the very recent readline
2106 4.2, without breaking for earlier versions.
2107
2108- Hopefully fixed a buffering problem in linuxaudiodev.
2109
2110- Attempted a fix to make the OpenSSL support in the socket module
2111 work again with pre-0.9.5 versions of OpenSSL.
2112
2113Tests
2114
2115- Added a test case for asynchat and asyncore.
2116
2117- Removed coupling between tests where one test failing could break
2118 another.
2119
2120Tools
2121
2122- Ping added an interactive help browser to pydoc, fixed some nits
2123 in the rest of the pydoc code, and added some features to his
2124 inspect module.
2125
2126- An updated python-mode.el version 4.1 which integrates Ken
2127 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
2128 much nicer in XEmacs and Emacs. When stepping through your program
2129 with pdb, in either the shell window or the *Python* window, the
2130 source file and line will be tracked by an arrow. Very cool!
2131
2132- IDLE: syntax warnings in interactive mode are changed into errors.
2133
2134- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00002135 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00002136
2137- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002138
Barry Warsaw11e89c72001-04-11 20:37:57 +00002139
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002140What's New in Python 2.1 beta 2?
2141================================
2142
Guido van Rossum053ae352001-03-22 14:17:21 +00002143(Unlisted are many fixed bugs, more documentation, etc.)
2144
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002145Core language, builtins, and interpreter
2146
Guido van Rossum053ae352001-03-22 14:17:21 +00002147- The nested scopes work (enabled by "from __future__ import
2148 nested_scopes") is completed; in particular, the future now extends
2149 into code executed through exec, eval() and execfile(), and into the
2150 interactive interpreter.
2151
2152- When calling a base class method (e.g. BaseClass.__init__(self)),
2153 this is now allowed even if self is not strictly spoken a class
2154 instance (e.g. when using metaclasses or the Don Beaudry hook).
2155
2156- Slice objects are now comparable but not hashable; this prevents
2157 dict[:] from being accepted but meaningless.
2158
2159- Complex division is now calculated using less braindead algorithms.
2160 This doesn't change semantics except it's more likely to give useful
2161 results in extreme cases. Complex repr() now uses full precision
2162 like float repr().
2163
2164- sgmllib.py now calls handle_decl() for simple <!...> declarations.
2165
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002166- It is illegal to assign to the name __debug__, which is set when the
2167 interpreter starts. It is effectively a compile-time constant.
2168
2169- A warning will be issued if a global statement for a variable
2170 follows a use or assignment of that variable.
2171
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002172Standard library
2173
Guido van Rossum053ae352001-03-22 14:17:21 +00002174- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
2175 inspired by JUnit), is now part of the standard library. You now
2176 have a choice of two testing frameworks: unittest requires you to
2177 write testcases as separate code, doctest gathers them from
2178 docstrings. Both approaches have their advantages and
2179 disadvantages.
2180
2181- A new module Tix was added, which wraps the Tix extension library
2182 for Tk. With that module, it is not necessary to statically link
2183 Tix with _tkinter, since Tix will be loaded with Tcl's "package
2184 require" command. See Demo/tix/.
2185
2186- tzparse.py is now obsolete.
2187
2188- In gzip.py, the seek() and tell() methods are removed -- they were
2189 non-functional anyway, and it's better if callers can test for their
2190 existence with hasattr().
2191
2192Python/C API
2193
2194- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
2195 that's already in the dictionary during a PyDict_Next() iteration.
2196 This used to fail occasionally when a dictionary resize operation
2197 could be triggered that would rehash all the keys. All other
2198 modifications to the dictionary are still off-limits during a
2199 PyDict_Next() iteration!
2200
2201- New extended APIs related to passing compiler variables around.
2202
2203- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
2204 implement isinstance() and issubclass().
2205
2206- Py_BuildValue() now has a "D" conversion to create a Python complex
2207 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002208
Fred Drake4e262a92001-03-22 18:26:47 +00002209- Extensions types which support weak references must now set the
2210 field allocated for the weak reference machinery to NULL themselves;
2211 this is done to avoid the cost of checking each object for having a
2212 weakly referencable type in PyObject_INIT(), since most types are
2213 not weakly referencable.
2214
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002215- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
2216 free variables and cell variables to and from the frame's f_locals.
2217
2218- Variants of several functions defined in pythonrun.h have been added
2219 to support the nested_scopes future statement. The variants all end
2220 in Flags and take an extra argument, a PyCompilerFlags *; examples:
2221 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
2222 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00002223 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002224
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002225Distutils
2226
2227- the sdist command now writes a PKG-INFO file, as described in PEP 241,
2228 into the release tree.
2229
Tim Peters0e57abf2001-05-02 07:39:38 +00002230- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002231 (an uninstaller, more customization of the installer's display)
2232
2233- from Jack Jansen: added Mac-specific code to generate a dialog for
2234 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00002235 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002236 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00002237
2238- added 'platforms' and 'keywords' to the set of metadata that can be
2239 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002240
2241- applied patches from Jason Tishler to make the compiler class work with
2242 Cygwin.
2243
2244
Tim Peters2fe289a2001-03-01 22:19:38 +00002245What's New in Python 2.1 beta 1?
2246================================
Tim Petersd66595f2001-02-04 03:09:53 +00002247
2248Core language, builtins, and interpreter
2249
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00002250- Following an outcry from the community about the amount of code
2251 broken by the nested scopes feature introduced in 2.1a2, we decided
2252 to make this feature optional, and to wait until Python 2.2 (or at
2253 least 6 months) to make it standard. The option can be enabled on a
2254 per-module basis by adding "from __future__ import nested_scopes" at
2255 the beginning of a module (before any other statements, but after
2256 comments and an optional docstring). See PEP 236 (Back to the
2257 __future__) for a description of the __future__ statement. PEP 227
2258 (Statically Nested Scopes) has been updated to reflect this change,
2259 and to clarify the semantics in a number of endcases.
2260
2261- The nested scopes code, when enabled, has been hardened, and most
2262 bugs and memory leaks in it have been fixed.
2263
2264- Compile-time warnings are now generated for a number of conditions
2265 that will break or change in meaning when nested scopes are enabled:
2266
2267 - Using "from...import *" or "exec" without in-clause in a function
2268 scope that also defines a lambda or nested function with one or
2269 more free (non-local) variables. The presence of the import* or
2270 bare exec makes it impossible for the compiler to determine the
2271 exact set of local variables in the outer scope, which makes it
2272 impossible to determine the bindings for free variables in the
2273 inner scope. To avoid the warning about import *, change it into
2274 an import of explicitly name object, or move the import* statement
2275 to the global scope; to avoid the warning about bare exec, use
2276 exec...in... (a good idea anyway -- there's a possibility that
2277 bare exec will be deprecated in the future).
2278
2279 - Use of a global variable in a nested scope with the same name as a
2280 local variable in a surrounding scope. This will change in
2281 meaning with nested scopes: the name in the inner scope will
2282 reference the variable in the outer scope rather than the global
2283 of the same name. To avoid the warning, either rename the outer
2284 variable, or use a global statement in the inner function.
2285
Neil Schemenauera35c6882001-02-27 04:45:05 +00002286- An optional object allocator has been included. This allocator is
2287 optimized for Python objects and should be faster and use less memory
2288 than the standard system allocator. It is not enabled by default
2289 because of possible thread safety problems. The allocator is only
2290 protected by the Python interpreter lock and it is possible that some
2291 extension modules require a thread safe allocator. The object
2292 allocator can be enabled by providing the "--with-pymalloc" option to
2293 configure.
2294
Tim Petersd66595f2001-02-04 03:09:53 +00002295Standard library
2296
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002297- pyexpat now detects the expat version if expat.h defines it. A
2298 number of additional handlers are provided, which are only available
2299 since expat 1.95. In addition, the methods SetParamEntityParsing and
2300 GetInputContext of Parser objects are available with 1.95.x
2301 only. Parser objects now provide the ordered_attributes and
2302 specified_attributes attributes. A new module expat.model was added,
2303 which offers a number of additional constants if 1.95.x is used.
2304
2305- xml.dom offers the new functions registerDOMImplementation and
2306 getDOMImplementation.
2307
2308- xml.dom.minidom offers a toprettyxml method. A number of DOM
2309 conformance issues have been resolved. In particular, Element now
2310 has an hasAttributes method, and the handling of namespaces was
2311 improved.
2312
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002313- Ka-Ping Yee contributed two new modules: inspect.py, a module for
2314 getting information about live Python code, and pydoc.py, a module
2315 for interactively converting docstrings to HTML or text.
2316 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002317 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002318 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2319 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002320
Tim Peters1eff7962001-03-01 02:31:33 +00002321- New library module difflib.py, primarily packaging the SequenceMatcher
2322 class at the heart of the popular ndiff.py file-comparison tool.
2323
2324- doctest.py (a framework for verifying Python code examples in docstrings)
2325 is now part of the std library.
2326
Tim Petersd66595f2001-02-04 03:09:53 +00002327Windows changes
2328
Guido van Rossume3955a82001-03-02 14:05:59 +00002329- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2330 small GUI that lets you browse the module docstrings using your
2331 default web browser.
2332
Tim Peters1eff7962001-03-01 02:31:33 +00002333- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2334 Platforms) is implemented. See
2335
2336 http://python.sourceforge.net/peps/pep-0235.html
2337
2338 for full details, especially the "Current Lower-Left Semantics" section.
2339 The new Windows import rules are simpler than before:
2340
2341 A. If the PYTHONCASEOK environment variable exists, same as
2342 before: silently accept the first case-insensitive match of any
2343 kind; raise ImportError if none found.
2344
2345 B. Else search sys.path for the first case-sensitive match; raise
2346 ImportError if none found.
2347
2348 The same rules have been implented on other platforms with case-
2349 insensitive but case-preserving filesystems too (including Cygwin, and
2350 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002351
Tim Peters25a9ce32001-02-19 07:06:36 +00002352- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2353 what it's supposed to do (and does do under NT and 2000) via direct
2354 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002355 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002356 all Win9x systems before.
2357
Tim Peters1eff7962001-03-01 02:31:33 +00002358- Build: Subproject _test (effectively) renamed to _testcapi.
2359
Tim Peters2fe289a2001-03-01 22:19:38 +00002360New platforms
2361
2362- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2363 Thanks to Steven Majewski!
2364
2365- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2366 Tishler!
2367
Guido van Rossum9089b272001-03-02 06:49:50 +00002368- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2369 Schwertberger! See RISCOS/README for more information -- it seems
2370 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002371 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002372
Tim Peters25a9ce32001-02-19 07:06:36 +00002373
Tim Petersd7b5e882001-01-25 03:36:26 +00002374What's New in Python 2.1 alpha 2?
2375=================================
Tim Peters40ead762001-01-27 05:35:26 +00002376
Tim Petersd7b5e882001-01-25 03:36:26 +00002377Core language, builtins, and interpreter
2378
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002379- Scopes nest. If a name is used in a function or class, but is not
2380 local, the definition in the nearest enclosing function scope will
2381 be used. One consequence of this change is that lambda statements
2382 could reference variables in the namespaces where the lambda is
2383 defined. In some unusual cases, this change will break code.
2384
2385 In all previous version of Python, names were resolved in exactly
2386 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002387 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002388 function A is defined within a function B, the names bound in B are
2389 not visible in A. The new rules make names bound in B visible in A,
2390 unless A contains a name binding that hides the binding in B.
2391
2392 Section 4.1 of the reference manual describes the new scoping rules
2393 in detail. The test script in Lib/test/test_scope.py demonstrates
2394 some of the effects of the change.
2395
2396 The new rules will cause existing code to break if it defines nested
2397 functions where an outer function has local variables with the same
2398 name as globals or builtins used by the inner function. Example:
2399
2400 def munge(str):
2401 def helper(x):
2402 return str(x)
2403 if type(str) != type(''):
2404 str = helper(str)
2405 return str.strip()
2406
2407 Under the old rules, the name str in helper() is bound to the
2408 builtin function str(). Under the new rules, it will be bound to
2409 the argument named str and an error will occur when helper() is
2410 called.
2411
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002412- The compiler will report a SyntaxError if "from ... import *" occurs
2413 in a function or class scope. The language reference has documented
2414 that this case is illegal, but the compiler never checked for it.
2415 The recent introduction of nested scope makes the meaning of this
2416 form of name binding ambiguous. In a future release, the compiler
2417 may allow this form when there is no possibility of ambiguity.
2418
Tim Peters40ead762001-01-27 05:35:26 +00002419- repr(string) is easier to read, now using hex escapes instead of octal,
2420 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2421
2422 >>> "\texample \r\n" + chr(0) + chr(255)
2423 '\texample \r\n\x00\xff' # in 2.1
2424 '\011example \015\012\000\377' # in 2.0
2425
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002426- Functions are now compared and hashed by identity, not by value, since
2427 the func_code attribute is writable.
2428
Fred Drakefb9d7122001-02-01 20:00:40 +00002429- Weak references (PEP 205) have been added. This involves a few
2430 changes in the core, an extension module (_weakref), and a Python
2431 module (weakref). The weakref module is the public interface. It
2432 includes support for "explicit" weak references, proxy objects, and
2433 mappings with weakly held values.
2434
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002435- A 'continue' statement can now appear in a try block within the body
2436 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002437 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002438
Tim Petersd7b5e882001-01-25 03:36:26 +00002439Standard library
2440
Barry Warsaw30dbd142001-01-31 22:14:01 +00002441- mailbox.py now has a new class, PortableUnixMailbox which is
2442 identical to UnixMailbox but uses a more portable scheme for
2443 determining From_ separators. Also, the constructors for all the
2444 classes in this module have a new optional `factory' argument, which
2445 is a callable used when new message classes must be instantiated by
2446 the next() method.
2447
Tim Petersd7b5e882001-01-25 03:36:26 +00002448- random.py is now self-contained, and offers all the functionality of
2449 the now-deprecated whrandom.py. See the docs for details. random.py
2450 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002451 and restoring the internal state of the generator; and jumpahead(n),
2452 for quickly forcing the internal state to be the same as if n calls to
2453 random() had been made. The latter is particularly useful for multi-
2454 threaded programs, creating one instance of the random.Random() class for
2455 each thread, then using .jumpahead() to force each instance to use a
2456 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002457
Tim Peters0de88fc2001-02-01 04:59:18 +00002458- random.py's seed() function is new. For bit-for-bit compatibility with
2459 prior releases, use the whseed function instead. The new seed function
2460 addresses two problems: (1) The old function couldn't produce more than
2461 about 2**24 distinct internal states; the new one about 2**45 (the best
2462 that can be done in the Wichmann-Hill generator). (2) The old function
2463 sometimes produced identical internal states when passed distinct
2464 integers, and there was no simple way to predict when that would happen;
2465 the new one guarantees to produce distinct internal states for all
2466 arguments in [0, 27814431486576L).
2467
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002468- The socket module now supports raw packets on Linux. The socket
2469 family is AF_PACKET.
2470
Tim Peters9ea17ac2001-02-02 05:57:15 +00002471- test_capi.py is a start at running tests of the Python C API. The tests
2472 are implemented by the new Modules/_testmodule.c.
2473
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002474- A new extension module, _symtable, provides provisional access to the
2475 internal symbol table used by the Python compiler. A higher-level
2476 interface will be added on top of _symtable in a future release.
2477
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002478- Removed the obsolete soundex module.
2479
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002480- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2481 the isSameNode method; NamedNodeMap the get method.
2482
2483- xml.sax.expatreader supports the lexical handler property; it
2484 generates comment, startCDATA, and endCDATA events.
2485
Tim Petersee826f82001-01-31 19:39:44 +00002486Windows changes
2487
2488- Build procedure: the zlib project is built in a different way that
2489 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002490 the zlib binary used. See PCbuild\readme.txt for details. Your old
2491 zlib-related directories can be deleted; you'll need to download fresh
2492 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002493
Tim Peters9ea17ac2001-02-02 05:57:15 +00002494- Build: New subproject _test for the benefit of test_capi.py (see above).
2495
Tim Petersb16c56f2001-02-02 21:24:51 +00002496- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2497 interface to some Python compiler internals).
2498
2499- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002500 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002501
Tim Petersa3a3a032000-11-30 05:22:44 +00002502What's New in Python 2.1 alpha 1?
2503=================================
2504
2505Core language, builtins, and interpreter
2506
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002507- There is a new Unicode companion to the PyObject_Str() API
2508 called PyObject_Unicode(). It behaves in the same way as the
2509 former, but assures that the returned value is an Unicode object
2510 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002511
Guido van Rossumf98eda02001-01-17 15:54:45 +00002512- The comparison operators support "rich comparison overloading" (PEP
2513 207). C extension types can provide a rich comparison function in
2514 the new tp_richcompare slot in the type object. The cmp() function
2515 and the C function PyObject_Compare() first try the new rich
2516 comparison operators before trying the old 3-way comparison. There
2517 is also a new C API PyObject_RichCompare() (which also falls back on
2518 the old 3-way comparison, but does not constrain the outcome of the
2519 rich comparison to a Boolean result).
2520
2521 The rich comparison function takes two objects (at least one of
2522 which is guaranteed to have the type that provided the function) and
2523 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2524 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2525 object, which may be NotImplemented (in which case the tp_compare
2526 slot function is used as a fallback, if defined).
2527
2528 Classes can overload individual comparison operators by defining one
2529 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002530 __ge__. There are no explicit "reflected argument" versions of
2531 these; instead, __lt__ and __gt__ are each other's reflection,
2532 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2533 reflection (similar at the C level). No other implications are
2534 made; in particular, Python does not assume that == is the Boolean
2535 inverse of !=, or that < is the Boolean inverse of >=. This makes
2536 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002537
2538 Classes or types that want to implement (in)equality tests but not
2539 the ordering operators (i.e. unordered types) should implement ==
2540 and !=, and raise an error for the ordering operators.
2541
Guido van Rossuma88479f2001-01-18 14:28:08 +00002542 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002543 Boolean; e.g. a matrix type might want to return a matrix of bits
2544 for A < B, giving elementwise comparisons. Such types should ensure
2545 that any interpretation of their value in a Boolean context raises
2546 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2547 at the C level) to always raise an exception.
2548
Guido van Rossuma88479f2001-01-18 14:28:08 +00002549- Complex numbers use rich comparisons to define == and != but raise
2550 an exception for <, <=, > and >=. Unfortunately, this also means
2551 that cmp() of two complex numbers raises an exception when the two
2552 numbers differ. Since it is not mathematically meaningful to compare
2553 complex numbers except for equality, I hope that this doesn't break
2554 too much code.
2555
Tim Peters3389f192001-02-18 08:48:49 +00002556- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002557 not defined by the language, other than that it's arbitrary but
2558 consistent (see the Reference Manual). An implementation detail changed
2559 in 2.1a1 such that None now compares less than any other object. Code
2560 relying on this new behavior (like code that relied on the previous
2561 behavior) does so at its own risk.
2562
Barry Warsaw573b5412001-01-15 20:43:18 +00002563- Functions and methods now support getting and setting arbitrarily
2564 named attributes (PEP 232). Functions have a new __dict__
2565 (a.k.a. func_dict) which hold the function attributes. Methods get
2566 and set attributes on their underlying im_func. It is a TypeError
2567 to set an attribute on a bound method.
2568
Guido van Rossum051e3352001-01-15 19:11:10 +00002569- The xrange() object implementation has been improved so that
2570 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2571 limitation that in this case len(xrange(sys.maxint)) can't be
2572 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2573 work fine as long as the index i doesn't actually reach 2**31.
2574 (Python uses regular ints for sequence and string indices; fixing
2575 that is much more work.)
2576
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002577- Two changes to from...import:
2578
Guido van Rossumba381232001-02-03 15:06:40 +00002579 1) "from M import X" now works even if (after loading module M)
2580 sys.modules['M'] is not a real module; it's basically a getattr()
2581 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002582
2583 2) "from M import *" now looks for M.__all__ to decide which names to
2584 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2585 filters out names starting with '_' as before. Whether or not
2586 __all__ exists, there's no restriction on the type of M.
2587
Guido van Rossumf61f1662001-01-10 20:13:55 +00002588- File objects have a new method, xreadlines(). This is the fastest
2589 way to iterate over all lines in a file:
2590
2591 for line in file.xreadlines():
2592 ...do something to line...
2593
2594 See the xreadlines module (mentioned below) for how to do this for
2595 other file-like objects.
2596
2597- Even if you don't use file.xreadlines(), you may expect a speedup on
2598 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002599 quite a bit in platform-specific ways: on systems (like Linux) that
2600 support flockfile(), getc_unlocked(), and funlockfile(), those are
2601 used by default. On systems (like Windows) without getc_unlocked(),
2602 a complicated (but still thread-safe) method using fgets() is used by
2603 default.
2604
Tim Petersd52269b2001-01-25 06:23:18 +00002605 You can force use of the fgets() method by #define'ing
2606 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002607 getc_unlocked()).
2608
Tim Petersd52269b2001-01-25 06:23:18 +00002609 You can force fgets() not to be used by #define'ing
2610 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002611 test_bufio.py fails -- and let us know if it does!).
2612
2613- In addition, the fileinput module, while still slower than the other
2614 methods on most platforms, has been sped up too, by using
2615 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002616
2617- Support for run-time warnings has been added, including a new
2618 command line option (-W) to specify the disposition of warnings.
2619 See the description of the warnings module below.
2620
2621- Extensive changes have been made to the coercion code. This mostly
2622 affects extension modules (which can now implement mixed-type
2623 numerical operators without having to use coercion), but
2624 occasionally, in boundary cases the coercion semantics have changed
2625 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002626 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002627 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002628 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002629
Guido van Rossumf98eda02001-01-17 15:54:45 +00002630- In connection with the coercion changes, a new built-in singleton
2631 object, NotImplemented is defined. This can be returned for
2632 operations that wish to indicate they are not implemented for a
2633 particular combination of arguments. From C, this is
2634 Py_NotImplemented.
2635
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002636- The interpreter accepts now bytecode files on the command line even
2637 if they do not have a .pyc or .pyo extension. On Linux, after executing
2638
Martin v. Löwise214baa2001-02-04 22:37:56 +00002639import imp,sys,string
2640magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2641reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2642open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002643
2644 any byte code file can be used as an executable (i.e. as an argument
2645 to execve(2)).
2646
Tim Peters9940b802000-12-01 07:59:35 +00002647- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002648 character. In 1.6 and earlier, they never produced a sign,
2649 and raised an error if the value of the long was too large
2650 to fit in a Python int. In 2.0, they produced a sign if and
2651 only if too large to fit in an int. This was inconsistent
2652 across platforms (because the size of an int varies across
2653 platforms), and inconsistent with hex() and oct(). Example:
2654
2655 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002656 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002657 'ffffffbe' # in 2.0 and before, on 32-bit machines
2658 >>> hex(-0x42L)
2659 '-0x42L' # in all versions of Python
2660
Tim Peters9940b802000-12-01 07:59:35 +00002661 The behavior of %d formats for negative Python longs remains
2662 the same as in 2.0 (although in 1.6 and before, they raised
2663 an error if the long didn't fit in a Python int).
2664
2665 %u formats don't make sense for Python longs, but are allowed
2666 and treated the same as %d in 2.1. In 2.0, a negative long
2667 formatted via %u produced a sign if and only if too large to
2668 fit in an int. In 1.6 and earlier, a negative long formatted
2669 via %u raised an error if it was too big to fit in an int.
2670
Guido van Rossum3661d392000-12-12 22:10:31 +00002671- Dictionary objects have an odd new method, popitem(). This removes
2672 an arbitrary item from the dictionary and returns it (in the form of
2673 a (key, value) pair). This can be useful for algorithms that use a
2674 dictionary as a bag of "to do" items and repeatedly need to pick one
2675 item. Such algorithms normally end up running in quadratic time;
2676 using popitem() they can usually be made to run in linear time.
2677
Tim Peters36cdad12000-12-29 02:06:45 +00002678Standard library
2679
Thomas Woutersfe385252001-01-19 23:16:56 +00002680- In the time module, the time argument to the functions strftime,
2681 localtime, gmtime, asctime and ctime is now optional, defaulting to
2682 the current time (in the local timezone).
2683
Guido van Rossumda91f222001-01-15 16:36:08 +00002684- The ftplib module now defaults to passive mode, which is deemed a
2685 more useful default given that clients are often inside firewalls
2686 these days. Note that this could break if ftplib is used to connect
2687 to a *server* that is inside a firewall, from outside; this is
2688 expected to be a very rare situation. To fix that, you can call
2689 ftp.set_pasv(0).
2690
Martin v. Löwis10a27872001-01-13 09:54:41 +00002691- The module site now treats .pth files not only for path configuration,
2692 but also supports extensions to the initialization code: Lines starting
2693 with import are executed.
2694
Guido van Rossumf61f1662001-01-10 20:13:55 +00002695- There's a new module, warnings, which implements a mechanism for
2696 issuing and filtering warnings. There are some new built-in
2697 exceptions that serve as warning categories, and a new command line
2698 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2699 turns warnings into errors). warnings.warn(message[, category])
2700 issues a warning message; this can also be called from C as
2701 PyErr_Warn(category, message).
2702
2703- A new module xreadlines was added. This exports a single factory
2704 function, xreadlines(). The intention is that this code is the
2705 absolutely fastest way to iterate over all lines in an open
2706 file(-like) object:
2707
2708 import xreadlines
2709 for line in xreadlines.xreadlines(file):
2710 ...do something to line...
2711
2712 This is equivalent to the previous the speed record holder using
2713 file.readlines(sizehint). Note that if file is a real file object
2714 (as opposed to a file-like object), this is equivalent:
2715
2716 for line in file.xreadlines():
2717 ...do something to line...
2718
Tim Peters36cdad12000-12-29 02:06:45 +00002719- The bisect module has new functions bisect_left, insort_left,
2720 bisect_right and insort_right. The old names bisect and insort
2721 are now aliases for bisect_right and insort_right. XXX_right
2722 and XXX_left methods differ in what happens when the new element
2723 compares equal to one or more elements already in the list: the
2724 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002725 right. Code that doesn't care where equal elements end up should
2726 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002727
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002728- The new curses.panel module wraps the panel library that forms part
2729 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2730
Guido van Rossumf61f1662001-01-10 20:13:55 +00002731- The SocketServer module now sets the allow_reuse_address flag by
2732 default in the TCPServer class.
2733
2734- A new function, sys._getframe(), returns the stack frame pointer of
2735 the caller. This is intended only as a building block for
2736 higher-level mechanisms such as string interpolation.
2737
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002738- The pyexpat module supports a number of new handlers, which are
2739 available only in expat 1.2. If invocation of a callback fails, it
2740 will report an additional frame in the traceback. Parser objects
2741 participate now in garbage collection. If expat reports an unknown
2742 encoding, pyexpat will try to use a Python codec; that works only
2743 for single-byte charsets. The parser type objects is exposed as
2744 XMLParserObject.
2745
2746- xml.dom now offers standard definitions for symbolic node type and
2747 exception code constants, and a hierarchy of DOM exceptions. minidom
2748 was adjusted to use them.
2749
2750- The conformance of xml.dom.minidom to the DOM specification was
2751 improved. It detects a number of additional error cases; the
2752 previous/next relationship works even when the tree is modified;
2753 Node supports the normalize() method; NamedNodeMap, DocumentType and
2754 DOMImplementation classes were added; Element supports the
2755 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2756 method.
2757
Guido van Rossumf61f1662001-01-10 20:13:55 +00002758Build issues
2759
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002760- For Unix (and Unix-compatible) builds, configuration and building of
2761 extension modules is now greatly automated. Rather than having to
2762 edit the Modules/Setup file to indicate which modules should be
2763 built and where their include files and libraries are, a
2764 distutils-based setup.py script now takes care of building most
2765 extension modules. All extension modules built this way are built
2766 as shared libraries. Only a few modules that must be linked
2767 statically are still listed in the Setup file; you won't need to
2768 edit their configuration.
2769
2770- Python should now build out of the box on Cygwin. If it doesn't,
2771 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002772
2773- Python now always uses its own (renamed) implementation of getopt()
2774 -- there's too much variation among C library getopt()
2775 implementations.
2776
2777- C++ compilers are better supported; the CXX macro is always set to a
2778 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002779
Tim Petersd92dfe02000-12-12 01:18:41 +00002780Windows changes
2781
2782- select module: By default under Windows, a select() call
2783 can specify no more than 64 sockets. Python now boosts
2784 this Microsoft default to 512. If you need even more than
2785 that, see the MS docs (you'll need to #define FD_SETSIZE
2786 and recompile Python from source).
2787
Guido van Rossumf61f1662001-01-10 20:13:55 +00002788- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2789 subdirectory is no more!
2790
Tim Petersa3a3a032000-11-30 05:22:44 +00002791
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002792What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002793=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002794
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002795Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002796changes are in the file HISTORY. If you are making the jump directly
2797from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2798HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002799
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002800Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2801the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2802http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002803
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002804--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002805
2806======================================================================
2807
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002808What's new in 2.0 (since release candidate 1)?
2809==============================================
2810
2811Standard library
2812
2813- The copy_reg module was modified to clarify its intended use: to
2814 register pickle support for extension types, not for classes.
2815 pickle() will raise a TypeError if it is passed a class.
2816
2817- Fixed a bug in gettext's "normalize and expand" code that prevented
2818 it from finding an existing .mo file.
2819
2820- Restored support for HTTP/0.9 servers in httplib.
2821
Tim Peters989b7b92000-10-16 20:24:53 +00002822- The math module was changed to stop raising OverflowError in case of
2823 underflow, and return 0 instead in underflow cases. Whether Python
2824 used to raise OverflowError in case of underflow was platform-
2825 dependent (it did when the platform math library set errno to ERANGE
2826 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002827
2828- Fixed a bug in StringIO that occurred when the file position was not
2829 at the end of the file and write() was called with enough data to
2830 extend past the end of the file.
2831
2832- Fixed a bug that caused Tkinter error messages to get lost on
2833 Windows. The bug was fixed by replacing direct use of
2834 interp->result with Tcl_GetStringResult(interp).
2835
2836- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2837 redirect response.
2838
2839- Several changes were made to distutils: Some debugging code was
2840 removed from util. Fixed the installer used when an external zip
2841 program (like WinZip) is not found; the source code for this
2842 installer is in Misc/distutils. check_lib() was modified to behave
2843 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2844 test for whether installed modules are on sys.path was changed to
2845 use both normcase() and normpath().
2846
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002847- Several minor bugs were fixed in the xml package (the minidom,
2848 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002849
2850- The regression test driver (regrtest.py) behavior when invoked with
2851 -l changed: It now reports a count of objects that are recognized as
2852 garbage but not freed by the garbage collector.
2853
Tim Peters989b7b92000-10-16 20:24:53 +00002854- The regression test for the math module was changed to test
2855 exceptional behavior when the test is run in verbose mode. Python
2856 cannot yet guarantee consistent exception behavior across platforms,
2857 so the exception part of test_math is run only in verbose mode, and
2858 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002859
2860Internals
2861
2862- PyOS_CheckStack() has been disabled on Win64, where it caused
2863 test_sre to fail.
2864
2865Build issues
2866
2867- Changed compiler flags, so that gcc is always invoked with -Wall and
2868 -Wstrict-prototypes. Users compiling Python with GCC should see
2869 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002870 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002871 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002872
Tim Petersa3a3a032000-11-30 05:22:44 +00002873- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002874
2875Tools and other miscellany
2876
2877- The compiler in Tools/compiler was updated to support the new
2878 language features introduced in 2.0: extended print statement, list
2879 comprehensions, and augmented assignments. The new compiler should
2880 also be backwards compatible with Python 1.5.2; the compiler will
2881 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002882 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002883
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002884What's new in 2.0 release candidate 1 (since beta 2)?
2885=====================================================
2886
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002887What is release candidate 1?
2888
2889We believe that release candidate 1 will fix all known bugs that we
2890intend to fix for the 2.0 final release. This release should be a bit
2891more stable than the previous betas. We would like to see even more
2892widespread testing before the final release, so we are producing this
2893release candidate. The final release will be exactly the same unless
2894any show-stopping (or brown bag) bugs are found by testers of the
2895release candidate.
2896
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002897All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002898to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002899
2900Core language, builtins, and interpreter
2901
2902- A bug that caused crashes when __coerce__ was used with augmented
2903 assignment, e.g. +=, was fixed.
2904
2905- Raise ZeroDivisionError when raising zero to a negative number,
2906 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2907 power operator and the result of math.pow(0.0, -2.0) will vary by
2908 platform. On Linux, it raises a ValueError.
2909
2910- A bug in Unicode string interpolation was fixed that occasionally
2911 caused errors with formats including "%%". For example, the
2912 following expression "%% %s" % u"abc" no longer raises a TypeError.
2913
2914- Compilation of deeply nested expressions raises MemoryError instead
2915 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2916
2917- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2918 rendering them useless. They are now written in binary mode again.
2919
2920Standard library
2921
2922- Keyword arguments are now accepted for most pattern and match object
2923 methods in SRE, the standard regular expression engine.
2924
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002925- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002926 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002927
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002928- Several bugs in the Unicode handling and error handling in _tkinter
2929 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002930
2931- Fix memory management errors in Merge() and Tkapp_Call() routines.
2932
2933- Several changes were made to cStringIO to make it compatible with
2934 the file-like object interface and with StringIO. If operations are
2935 performed on a closed object, an exception is raised. The truncate
2936 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002937 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002938
2939- There were many changes made to the linuxaudiodev module and its
2940 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002941 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002942
2943 Note that this module is named poorly, because it should work
2944 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002945 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002946
2947 The module now raises exceptions when errors occur instead of
2948 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2949 audio) and defines a getptr() method that calls the
2950 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2951
2952- The library_version attribute, introduced in an earlier beta, was
2953 removed because it can not be supported with early versions of the C
2954 readline library, which provides no way to determine the version at
2955 compile-time.
2956
2957- The binascii module is now enabled on Win64.
2958
Tim Peters46446d62000-10-09 21:19:31 +00002959- tokenize.py no longer suffers "recursion depth" errors when parsing
2960 programs with very long string literals.
2961
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002962Internals
2963
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002964- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002965 which is called when the interpreter starts up to determine where
2966 the standard library is installed. These vulnerabilities affect all
2967 previous versions of Python and can be exploited by setting very
2968 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2969 setuid Python script, although use of the wrapper in
2970 Misc/setuid-prog.c will eliminate the vulnerability.
2971
2972- Fixed garbage collection bugs in instance creation that were
2973 triggered when errors occurred during initialization. The solution,
2974 applied in cPickle and in PyInstance_New(), is to call
2975 PyObject_GC_Init() after the initialization of the object's
2976 container attributes is complete.
2977
2978- pyexpat adds definitions of PyModule_AddStringConstant and
2979 PyModule_AddObject if the Python version is less than 2.0, which
2980 provides compatibility with PyXML on Python 1.5.2.
2981
2982- If the platform has a bogus definition for LONG_BIT (the number of
2983 bits in a long), an error will be reported at compile time.
2984
2985- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2986 collection crashes and possibly other, unreported crashes.
2987
2988- Fixed a memory leak in _PyUnicode_Fini().
2989
2990Build issues
2991
2992- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002993 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002994 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002995
2996- The mmap.PAGESIZE constant is now initialized using sysconf when
2997 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2998
2999- The md5 file should now compile on all platforms.
3000
3001- The select module now compiles on platforms that do not define
3002 POLLRDNORM and related constants.
3003
3004- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00003005 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003006
Jeremy Hylton10921202000-10-09 18:34:12 +00003007- BeOS: A number of changes were made to the build and installation
3008 process. ar-fake now operates on a directory of object files.
3009 dl_export.h is gone, and its macros now appear on the mwcc command
3010 line during build on PPC BeOS.
3011
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003012- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00003013 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003014
3015- Cygwin: Support for shared libraries, Tkinter, and sockets.
3016
3017- SunOS 4.1.4_JL: Fix test for directory existence in configure.
3018
3019Tools and other miscellany
3020
3021- Removed debugging prints from main used with freeze.
3022
Tim Peters46446d62000-10-09 21:19:31 +00003023- IDLE auto-indent no longer crashes when it encounters Unicode
3024 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003025
3026What's new in 2.0 beta 2 (since beta 1)?
3027========================================
3028
3029Core language, builtins, and interpreter
3030
Tim Peters482c0212000-09-26 06:33:09 +00003031- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003032 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003033
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003034- Add -h and -V command line options to print the usage message and
3035 Python version number and exit immediately.
3036
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003037- eval() and exec accept Unicode objects as code parameters.
3038
3039- getattr() and setattr() now also accept Unicode objects for the
3040 attribute name, which are converted to strings using the default
3041 encoding before lookup.
3042
3043- Multiplication on string and Unicode now does proper bounds
3044 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
3045 string is too long."
3046
3047- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00003048 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003049
Jeremy Hylton1b618592000-09-26 05:32:36 +00003050
3051Standard library and extensions
3052
Guido van Rossum5b08f132001-04-16 02:05:23 +00003053- socket module: the OpenSSL code now adds support for RAND_status()
3054 and EGD (Entropy Gathering Device).
3055
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003056- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00003057 argument checking; it still takes no arguments.
3058
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003059- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003060
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003061- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003062
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003063- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003064
3065- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003066 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003067
3068- copy: Copy Unicode objects atomically.
3069
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003070- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003071
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003072- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003073
Fred Drake67233bc2000-09-26 16:40:27 +00003074- dbm: Add get() and setdefault() methods to dbm object. Add constant
3075 `library' to module that names the library used. Added doc strings
3076 and method names to error messages. Uses configure to determine
3077 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
3078 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003079
3080- distutils: Update to version 0.9.3.
3081
3082- dl: Add several dl.RTLD_ constants.
3083
3084- fpectl: Now supported on FreeBSD.
3085
3086- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
3087 found by the collector will be saved in gc.garbage. This is useful
3088 for debugging a program that creates reference cycles.
3089
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003090- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00003091 of HTTP class. Do not close socket on zero-length response. Do not
3092 crash when server sends invalid content-length header.
3093
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003094- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003095
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003096- marshal: When reading a short, sign-extend on platforms where shorts
3097 are bigger than 16 bits. When reading a long, repair the unportable
3098 sign extension that was being done for 64-bit machines. (It assumed
3099 that signed right shift sign-extends.)
3100
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003101- operator: Add contains(), invert(), __invert__() as aliases for
3102 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003103
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003104- os: Add support for popen2() and popen3() on all platforms where
3105 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003106
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003107- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00003108 clicking on a file in Explorer (or passing the file name to the
3109 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003110
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003111- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00003112 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003113
3114- pickle: Now raises ValueError when an invalid pickle that contains
3115 a non-string repr where a string repr was expected. This behavior
3116 matches cPickle.
3117
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003118- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003119
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003120- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003121
3122- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003123 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003124 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003125
3126- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003127 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003128
3129- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00003130 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00003131 few cycles during startup since the first call to
3132 setdefaultencoding() will initialize the codec registry and the
3133 encodings package.
3134
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003135- socket: Support for size hint in readlines() method of object returned
3136 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003137
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003138- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00003139 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00003140 is followed by whitespace.
3141
Tim Petersa3a3a032000-11-30 05:22:44 +00003142- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003143
3144- struct: Check ranges for bytes and shorts.
3145
3146- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003147 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003148
3149- Tkinter: Image objects are now guaranteed to have unique ids. Set
3150 event.delta to zero if Tk version doesn't support mousewheel.
3151 Removed some debugging prints.
3152
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003153- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003154
Fred Drake67233bc2000-09-26 16:40:27 +00003155- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003156 which works around a bug in Norton AntiVirus 2000 that leads directly
3157 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003158
3159- xml: New version detection code allows PyXML to override standard
3160 XML package if PyXML version is greater than 0.6.1.
3161
Fred Drake64bb3802000-09-26 16:21:35 +00003162- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
3163 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
3164 tree only for nodes which are sufficiently interesting to a specific
3165 application. Does not provide the HTML-specific extensions. Still
3166 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003167
Fred Drake64bb3802000-09-26 16:21:35 +00003168- xml.sax: SAX 2 support for Python, including all the handler
3169 interfaces needed to process XML 1.0 compliant XML. Some
3170 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003171
Fred Drake64bb3802000-09-26 16:21:35 +00003172- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
3173 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003174
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003175
Jeremy Hylton1b618592000-09-26 05:32:36 +00003176C API
3177
3178- Add three new convenience functions for module initialization --
3179 PyModule_AddObject(), PyModule_AddIntConstant(), and
3180 PyModule_AddStringConstant().
3181
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003182- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00003183 removed and add #error to Python.h if NULL isn't defined after
3184 #include of stdio.h.
3185
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003186- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00003187 backwards compatibility (at the source level) with old extensions.
3188
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003189- A wrapper API was added for signal() and sigaction(). Instead of
3190 either function, always use PyOS_getsig() to get a signal handler
3191 and PyOS_setsig() to set one. A new convenience typedef
3192 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003193
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003194- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00003195 internal data buffer and size of a string object -- or the default
3196 encoded version of a Unicode object.
3197
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003198- PyString_Size() and PyString_AsString() accept Unicode objects.
3199
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003200- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00003201 exists). INT_MAX and LONG_MAX will always be defined, even if
3202 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003203
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003204- PyFloat_FromString takes a second argument, pend, that was
3205 effectively useless. It is now officially useless but preserved for
3206 backwards compatibility. If the pend argument is not NULL, *pend is
3207 set to NULL.
3208
3209- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
3210 for the attribute name. See note on getattr() above.
3211
3212- A few bug fixes to argument processing for Unicode.
3213 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
3214 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
3215 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00003216 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003217
3218- Py_BuildValue accepts B format (for bgen-generated code).
3219
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003220
Jeremy Hylton1b618592000-09-26 05:32:36 +00003221Internals
3222
3223- On Unix, fix code for finding Python installation directory so that
3224 it works when argv[0] is a relative path.
3225
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00003226- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003227 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00003228 rather than by generating a copy of the object.
3229
Tim Peters482c0212000-09-26 06:33:09 +00003230- Several of the internal Unicode tables are much smaller now, and
3231 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003232
Jeremy Hylton97693b02000-09-26 17:42:51 +00003233- In the garbage collector: Fixed bug in collection of tuples. Fixed
3234 bug that caused some instances to be removed from the container set
3235 while they were still live. Fixed parsing in gc.set_debug() for
3236 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003237
3238- Fixed refcount problem in instance deallocation that only occurred
3239 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
3240
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003241- On Windows, getpythonregpath is now protected against null data in
3242 registry key.
3243
3244- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00003245 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003246
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003247
Jeremy Hylton1b618592000-09-26 05:32:36 +00003248Build and platform-specific issues
3249
3250- Better support of GNU Pth via --with-pth configure option.
3251
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003252- Python/C API now properly exposed to dynamically-loaded extension
3253 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003254
3255- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
3256 Don't define MS_SYNC to be zero when it is undefined. Added missing
3257 prototypes in posixmodule.c.
3258
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003259- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003260 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003261
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003262- Fix largefile support on older NetBSD systems and OpenBSD by adding
3263 define for TELL64.
3264
3265
3266Tools and other miscellany
3267
3268- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
3269
3270- freeze: The modulefinder now works with 2.0 opcodes.
3271
Tim Petersa3a3a032000-11-30 05:22:44 +00003272- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003273 Move hackery of sys.argv until after the Tk instance has been
3274 created, which allows the application-specific Tkinter
3275 initialization to be executed if present; also pass an explicit
3276 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00003277
Jeremy Hylton1b618592000-09-26 05:32:36 +00003278
3279What's new in 2.0 beta 1?
3280=========================
3281
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003282Source Incompatibilities
3283------------------------
3284
3285None. Note that 1.6 introduced several incompatibilities with 1.5.2,
3286such as single-argument append(), connect() and bind(), and changes to
3287str(long) and repr(float).
3288
3289
3290Binary Incompatibilities
3291------------------------
3292
3293- Third party extensions built for Python 1.5.x or 1.6 cannot be used
3294with Python 2.0; these extensions will have to be rebuilt for Python
32952.0.
3296
3297- On Windows, attempting to import a third party extension built for
3298Python 1.5.x or 1.6 results in an immediate crash; there's not much we
3299can do about this. Check your PYTHONPATH environment variable!
3300
3301- Python bytecode files (*.pyc and *.pyo) are not compatible between
3302releases.
3303
3304
3305Overview of Changes Since 1.6
3306-----------------------------
3307
3308There are many new modules (including brand new XML support through
3309the xml package, and i18n support through the gettext module); a list
3310of all new modules is included below. Lots of bugs have been fixed.
3311
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003312The process for making major new changes to the language has changed
3313since Python 1.6. Enhancements must now be documented by a Python
3314Enhancement Proposal (PEP) before they can be accepted.
3315
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003316There are several important syntax enhancements, described in more
3317detail below:
3318
3319 - Augmented assignment, e.g. x += 1
3320
3321 - List comprehensions, e.g. [x**2 for x in range(10)]
3322
3323 - Extended import statement, e.g. import Module as Name
3324
3325 - Extended print statement, e.g. print >> file, "Hello"
3326
3327Other important changes:
3328
3329 - Optional collection of cyclical garbage
3330
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003331Python Enhancement Proposal (PEP)
3332---------------------------------
3333
3334PEP stands for Python Enhancement Proposal. A PEP is a design
3335document providing information to the Python community, or describing
3336a new feature for Python. The PEP should provide a concise technical
3337specification of the feature and a rationale for the feature.
3338
3339We intend PEPs to be the primary mechanisms for proposing new
3340features, for collecting community input on an issue, and for
3341documenting the design decisions that have gone into Python. The PEP
3342author is responsible for building consensus within the community and
3343documenting dissenting opinions.
3344
3345The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003346
3347Augmented Assignment
3348--------------------
3349
3350This must have been the most-requested feature of the past years!
3351Eleven new assignment operators were added:
3352
Guido van Rossume905e952000-09-05 12:42:46 +00003353 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003354
3355For example,
3356
3357 A += B
3358
3359is similar to
3360
3361 A = A + B
3362
3363except that A is evaluated only once (relevant when A is something
3364like dict[index].attr).
3365
3366However, if A is a mutable object, A may be modified in place. Thus,
3367if A is a number or a string, A += B has the same effect as A = A+B
3368(except A is only evaluated once); but if a is a list, A += B has the
3369same effect as A.extend(B)!
3370
3371Classes and built-in object types can override the new operators in
3372order to implement the in-place behavior; the not-in-place behavior is
3373used automatically as a fallback when an object doesn't implement the
3374in-place behavior. For classes, the method name is derived from the
3375method name for the corresponding not-in-place operator by inserting
3376an 'i' in front of the name, e.g. __iadd__ implements in-place
3377__add__.
3378
3379Augmented assignment was implemented by Thomas Wouters.
3380
3381
3382List Comprehensions
3383-------------------
3384
3385This is a flexible new notation for lists whose elements are computed
3386from another list (or lists). The simplest form is:
3387
3388 [<expression> for <variable> in <sequence>]
3389
Guido van Rossum56db0952000-09-06 23:34:25 +00003390For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003391This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003392
3393You can also add a condition:
3394
3395 [<expression> for <variable> in <sequence> if <condition>]
3396
3397For example, [w for w in words if w == w.lower()] would yield the list
3398of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003399than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003400
3401You can also have nested for loops and more than one 'if' clause. For
3402example, here's a function that flattens a sequence of sequences::
3403
3404 def flatten(seq):
3405 return [x for subseq in seq for x in subseq]
3406
3407 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3408
3409This prints
3410
3411 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3412
3413List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003414Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003415
3416
3417Extended Import Statement
3418-------------------------
3419
3420Many people have asked for a way to import a module under a different
3421name. This can be accomplished like this:
3422
3423 import foo
3424 bar = foo
3425 del foo
3426
3427but this common idiom gets old quickly. A simple extension of the
3428import statement now allows this to be written as follows:
3429
3430 import foo as bar
3431
3432There's also a variant for 'from ... import':
3433
3434 from foo import bar as spam
3435
3436This also works with packages; e.g. you can write this:
3437
3438 import test.regrtest as regrtest
3439
3440Note that 'as' is not a new keyword -- it is recognized only in this
3441context (this is only possible because the syntax for the import
3442statement doesn't involve expressions).
3443
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003444Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003445
3446
3447Extended Print Statement
3448------------------------
3449
3450Easily the most controversial new feature, this extension to the print
3451statement adds an option to make the output go to a different file
3452than the default sys.stdout.
3453
3454For example, to write an error message to sys.stderr, you can now
3455write:
3456
3457 print >> sys.stderr, "Error: bad dog!"
3458
3459As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003460evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003461
3462 print >> None, "Hello world"
3463
3464is equivalent to
3465
3466 print "Hello world"
3467
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003468Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003469
3470
3471Optional Collection of Cyclical Garbage
3472---------------------------------------
3473
3474Python is now equipped with a garbage collector that can hunt down
3475cyclical references between Python objects. It's no replacement for
3476reference counting; in fact, it depends on the reference counts being
3477correct, and decides that a set of objects belong to a cycle if all
3478their reference counts can be accounted for from their references to
3479each other. This devious scheme was first proposed by Eric Tiedemann,
3480and brought to implementation by Neil Schemenauer.
3481
3482There's a module "gc" that lets you control some parameters of the
3483garbage collection. There's also an option to the configure script
3484that lets you enable or disable the garbage collection. In 2.0b1,
3485it's on by default, so that we (hopefully) can collect decent user
3486experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003487performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003488off by default in the final 2.0 release.
3489
3490
3491Smaller Changes
3492---------------
3493
3494A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3495map(None, seq1, seq2, ...) when the sequences have the same length;
3496i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3497the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003498zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003499
3500sys.version_info is a tuple (major, minor, micro, level, serial).
3501
3502Dictionaries have an odd new method, setdefault(key, default).
3503dict.setdefault(key, default) returns dict[key] if it exists; if not,
3504it sets dict[key] to default and returns that value. Thus:
3505
3506 dict.setdefault(key, []).append(item)
3507
3508does the same work as this common idiom:
3509
3510 if not dict.has_key(key):
3511 dict[key] = []
3512 dict[key].append(item)
3513
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003514There are two new variants of SyntaxError that are raised for
3515indentation-related errors: IndentationError and TabError.
3516
3517Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3518escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003519
3520The limits on the size of expressions and file in Python source code
3521have been raised from 2**16 to 2**32. Previous versions of Python
3522were limited because the maximum argument size the Python VM accepted
3523was 2**16. This limited the size of object constructor expressions,
3524e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3525limit was raised thanks to a patch by Charles Waldman that effectively
3526fixes the problem. It is now much more likely that you will be
3527limited by available memory than by an arbitrary limit in Python.
3528
3529The interpreter's maximum recursion depth can be modified by Python
3530programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3531limit is the maximum number of recursive calls that can be made by
3532Python code. The limit exists to prevent infinite recursion from
3533overflowing the C stack and causing a core dump. The default value is
35341000. The maximum safe value for a particular platform can be found
3535by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003536
3537New Modules and Packages
3538------------------------
3539
3540atexit - for registering functions to be called when Python exits.
3541
3542imputil - Greg Stein's alternative API for writing custom import
3543hooks.
3544
3545pyexpat - an interface to the Expat XML parser, contributed by Paul
3546Prescod.
3547
3548xml - a new package with XML support code organized (so far) in three
3549subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3550would fill a volume. There's a special feature whereby a
3551user-installed package named _xmlplus overrides the standard
3552xmlpackage; this is intended to give the XML SIG a hook to distribute
3553backwards-compatible updates to the standard xml package.
3554
3555webbrowser - a platform-independent API to launch a web browser.
3556
3557
Guido van Rossume905e952000-09-05 12:42:46 +00003558Changed Modules
3559---------------
3560
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003561array -- new methods for array objects: count, extend, index, pop, and
3562remove
3563
3564binascii -- new functions b2a_hex and a2b_hex that convert between
3565binary data and its hex representation
3566
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003567calendar -- Many new functions that support features including control
3568over which day of the week is the first day, returning strings instead
3569of printing them. Also new symbolic constants for days of week,
3570e.g. MONDAY, ..., SUNDAY.
3571
3572cgi -- FieldStorage objects have a getvalue method that works like a
3573dictionary's get method and returns the value attribute of the object.
3574
3575ConfigParser -- The parser object has new methods has_option,
3576remove_section, remove_option, set, and write. They allow the module
3577to be used for writing config files as well as reading them.
3578
3579ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003580optionally support the RFC 959 REST command.
3581
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003582gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003583
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003584httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3585the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003586
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003587locale -- implement getdefaultlocale for Win32 and Macintosh
3588
3589marshal -- no longer dumps core when marshaling deeply nested or
3590recursive data structures
3591
3592os -- new functions isatty, seteuid, setegid, setreuid, setregid
3593
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003594os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3595support under Unix.
3596
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003597os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003598
3599os.path -- fix semantics of os.path.commonprefix
3600
3601smtplib -- support for sending very long messages
3602
3603socket -- new function getfqdn()
3604
3605readline -- new functions to read, write and truncate history files.
3606The readline section of the library reference manual contains an
3607example.
3608
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003609select -- add interface to poll system call
3610
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003611shutil -- new copyfileobj function
3612
3613SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3614HTTP server.
3615
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003616Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003617
3618urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003619e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003620
3621whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003622
3623
3624Obsolete Modules
3625----------------
3626
3627None. However note that 1.6 made a whole slew of modules obsolete:
3628stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3629poly, zmod, strop, util, whatsound.
3630
3631
3632Changed, New, Obsolete Tools
3633----------------------------
3634
Tim Peters8b092332000-09-05 20:15:25 +00003635None.
Guido van Rossume905e952000-09-05 12:42:46 +00003636
3637
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003638C-level Changes
3639---------------
3640
3641Several cleanup jobs were carried out throughout the source code.
3642
3643All C code was converted to ANSI C; we got rid of all uses of the
3644Py_PROTO() macro, which makes the header files a lot more readable.
3645
3646Most of the portability hacks were moved to a new header file,
3647pyport.h; several other new header files were added and some old
3648header files were removed, in an attempt to create a more rational set
3649of header files. (Few of these ever need to be included explicitly;
3650they are all included by Python.h.)
3651
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003652Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003653and Win64, especially for the new Intel Itanium processor. Mick also
3654added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003655
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003656The C APIs to return an object's size have been update to consistently
3657use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3658previous versions, the abstract interfaces used PyXXX_Length and the
3659concrete interfaces used PyXXX_Size. The old names,
3660e.g. PyObject_Length, are still available for backwards compatibility
3661at the API level, but are deprecated.
3662
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003663The PyOS_CheckStack function has been implemented on Windows by
3664Fredrik Lundh. It prevents Python from failing with a stack overflow
3665on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003666
3667The GC changes resulted in creation of two new slots on object,
3668tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003669the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003670
3671The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003672C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003673
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003674PyErr_Format has been updated to automatically calculate the size of
3675the buffer needed to hold the formatted result string. This change
3676prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003677
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003678New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003679
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003680PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3681that are the same as their non-Ex counterparts except they take an
3682extra flag argument that tells them to close the file when done.
3683
3684XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003685
Tim Peters8b092332000-09-05 20:15:25 +00003686
3687Windows Changes
3688---------------
3689
3690New popen2/popen3/peopen4 in os module (see Changed Modules above).
3691
3692os.popen is much more usable on Windows 95 and 98. See Microsoft
3693Knowledge Base article Q150956. The Win9x workaround described there
3694is implemented by the new w9xpopen.exe helper in the root of your
3695Python installation. Note that Python uses this internally; it is not
3696a standalone program.
3697
3698Administrator privileges are no longer required to install Python
3699on Windows NT or Windows 2000. If you have administrator privileges,
3700Python's registry info will be written under HKEY_LOCAL_MACHINE.
3701Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003702under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003703uses of Python, but will prevent some advanced uses from working
3704(for example, running a Python script as an NT service, or possibly
3705from CGI).
3706
3707[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3708installer; instead, it installs the needed Tcl/Tk files directly in the
3709Python directory. If you already have a Tcl/Tk installation, this
3710wastes some disk space (about 4 Megs) but avoids problems with
3711conflicting Tcl/Tk installations, and makes it much easier for Python
3712to ensure that Tcl/Tk can find all its files.
3713
3714[This was new in 1.6] The Windows installer now installs by default in
3715\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3716
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003717
3718Updates to the changes between 1.5.2 and 1.6
3719--------------------------------------------
3720
3721The 1.6 NEWS file can't be changed after the release is done, so here
3722is some late-breaking news:
3723
3724New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3725and changes to getlocale() and setlocale().
3726
3727The new module is now enabled per default.
3728
3729It is not true that the encodings codecs cannot be used for normal
3730strings: the string.encode() (which is also present on 8-bit strings
3731!) allows using them for 8-bit strings too, e.g. to convert files from
3732cp1252 (Windows) to latin-1 or vice-versa.
3733
3734Japanese codecs are available from Tamito KAJIYAMA:
3735http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3736
3737
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003738======================================================================