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Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001+++++++++++
2Python News
3+++++++++++
4
Skip Montanaro4a385832002-09-20 17:08:52 +00005(editors: check NEWS.help for information about editing NEWS using ReST.)
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Tim Petersaf8446f2001-12-21 21:36:50 +00007What's New in Python 2.3 alpha 1?
Tim Petersaf8446f2001-12-21 21:36:50 +00008=================================
9
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +000010*XXX Release date: DD-MMM-2002 XXX*
11
Tim Petersaf8446f2001-12-21 21:36:50 +000012Type/class unification and new-style classes
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +000013--------------------------------------------
Tim Petersaf8446f2001-12-21 21:36:50 +000014
Guido van Rossume3438782002-08-12 03:42:03 +000015- Assignment to __class__ is disallowed if either the old and the new
16 class is a statically allocated type object (such as defined by an
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +000017 extension module). This prevents anomalies like 2.__class__ = bool.
Guido van Rossume3438782002-08-12 03:42:03 +000018
19- New-style object creation and deallocation have been sped up
20 significantly; they are now faster than classic instance creation
21 and deallocation.
22
23- The __slots__ variable can now mention "private" names, and the
24 right thing will happen (e.g. __slots__ = ["__foo"]).
25
26- The built-ins slice() and buffer() are now callable types. The
27 types classobj (formerly class), code, function, instance, and
28 instancemethod (formerly instance-method), which have no built-in
29 names but are accessible through the types module, are now also
30 callable. The type dict-proxy is renamed to dictproxy.
31
32- Cycles going through the __class__ link of a new-style instance are
33 now detected by the garbage collector.
34
35- Classes using __slots__ are now properly garbage collected.
36 [SF bug 519621]
37
38- Tightened the __slots__ rules: a slot name must be a valid Python
39 identifier.
40
41- The constructor for the module type now requires a name argument and
42 takes an optional docstring argument. Previously, this constructor
43 ignored its arguments. As a consequence, deriving a class from a
44 module (not from the module type) is now illegal; previously this
45 created an unnamed module, just like invoking the module type did.
46 [SF bug 563060]
47
48- A new type object, 'basestring', is added. This is a common base type
49 for 'str' and 'unicode', and can be used instead of
50 types.StringTypes, e.g. to test whether something is "a string":
51 isinstance(x, basestring) is True for Unicode and 8-bit strings. This
52 is an abstract base class and cannot be instantiated directly.
53
54- Changed new-style class instantiation so that when C's __new__
55 method returns something that's not a C instance, its __init__ is
56 not called. [SF bug #537450]
57
58- Fixed super() to work correctly with class methods. [SF bug #535444]
59
60- If you try to pickle an instance of a class that has __slots__ but
61 doesn't define or override __getstate__, a TypeError is now raised.
62 This is done by adding a bozo __getstate__ to the class that always
63 raises TypeError. (Before, this would appear to be pickled, but the
64 state of the slots would be lost.)
65
Tim Petersaf8446f2001-12-21 21:36:50 +000066Core and builtins
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +000067-----------------
Tim Petersaf8446f2001-12-21 21:36:50 +000068
Martin v. Löwisa844f2d2002-10-05 09:46:48 +000069- Unicode file name processing for Windows (PEP 277) is implemented.
Mark Hammond8696ebc2002-10-08 02:44:31 +000070 All platforms now have an os.path.supports_unicode_filenames attribute,
71 which is set to True on Windows NT/2000/XP, and False elsewhere.
Martin v. Löwisa844f2d2002-10-05 09:46:48 +000072
Walter Dörwald3aeb6322002-09-02 13:14:32 +000073- Codec error handling callbacks (PEP 293) are implemented.
74 Error handling in unicode.encode or str.decode can now be customized.
75
Guido van Rossum45ec02a2002-08-19 21:43:18 +000076- A subtle change to the semantics of the built-in function intern():
77 interned strings are no longer immortal. You must keep a reference
78 to the return value intern() around to get the benefit.
79
Guido van Rossumf808b892002-08-16 03:38:10 +000080- Use of 'None' as a variable, argument or attribute name now
81 issues a SyntaxWarning. In the future, None may become a keyword.
82
Michael W. Hudsondd32a912002-08-15 14:59:02 +000083- SET_LINENO is gone. co_lnotab is now consulted to determine when to
84 call the trace function. C code that accessed f_lineno should call
85 PyCode_Addr2Line instead (f_lineno is still there, but not kept up
86 to date).
87
Guido van Rossum9be89462002-08-14 16:11:30 +000088- There's a new warning category, FutureWarning. This is used to warn
89 about a number of situations where the value or sign of an integer
90 result will change in Python 2.4 as a result of PEP 237 (integer
91 unification). The warnings implement stage B0 mentioned in that
92 PEP. The warnings are about the following situations:
93
94 - Octal and hex literals without 'L' prefix in the inclusive range
95 [0x80000000..0xffffffff]; these are currently negative ints, but
96 in Python 2.4 they will be positive longs with the same bit
97 pattern.
98
99 - Left shifts on integer values that cause the outcome to lose
100 bits or have a different sign than the left operand. To be
101 precise: x<<n where this currently doesn't yield the same value
102 as long(x)<<n; in Python 2.4, the outcome will be long(x)<<n.
103
104 - Conversions from ints to string that show negative values as
105 unsigned ints in the inclusive range [0x80000000..0xffffffff];
106 this affects the functions hex() and oct(), and the string
107 formatting codes %u, %o, %x, and %X. In Python 2.4, these will
108 show signed values (e.g. hex(-1) currently returns "0xffffffff";
109 in Python 2.4 it will return "-0x1").
110
Skip Montanaro979c74b2002-09-03 21:25:14 +0000111 - The bits manipulated under the cover by sys.setcheckinterval() have
112 been changed. Both the check interval and the ticker used to be
113 per-thread values. They are now just a pair of global variables. In
114 addition, the default check interval was boosted from 10 to 100
Neal Norwitz7165af22002-09-05 21:42:24 +0000115 bytecode instructions. This may have some effect on systems that
116 relied on the old default value. In particular, in multi-threaded
117 applications which try to be highly responsive, response time will
118 increase by some (perhaps imperceptible) amount.
Skip Montanaro979c74b2002-09-03 21:25:14 +0000119
Tim Petersd64c1de2002-08-12 17:36:03 +0000120- When multiplying very large integers, a version of the so-called
121 Karatsuba algorithm is now used. This is most effective if the
122 inputs have roughly the same size. If they both have about N digits,
123 Karatsuba multiplication has O(N**1.58) runtime (the exponent is
124 log_base_2(3)) instead of the previous O(N**2). Measured results may
Tim Peters012c0a32002-08-16 03:40:07 +0000125 be better or worse than that, depending on platform quirks. Besides
126 the O() improvement in raw instruction count, the Karatsuba algorithm
127 appears to have much better cache behavior on extremely large integers
128 (starting in the ballpark of a million bits). Note that this is a
129 simple implementation, and there's no intent here to compete with,
130 e.g., GMP. It gives a very nice speedup when it applies, but a package
131 devoted to fast large-integer arithmetic should run circles around it.
Tim Peters5af4e6c2002-08-12 02:31:19 +0000132
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +0000133- u'%c' will now raise a ValueError in case the argument is an
134 integer outside the valid range of Unicode code point ordinals.
135
Guido van Rossumdeb09362002-08-09 17:16:30 +0000136- The tempfile module has been overhauled for enhanced security. The
137 mktemp() function is now deprecated; new, safe replacements are
138 mkstemp() (for files) and mkdtemp() (for directories), and the
139 higher-level functions NamedTemporaryFile() and TemporaryFile().
140 Use of some global variables in this module is also deprecated; the
141 new functions have keyword arguments to provide the same
142 functionality. All Lib, Tools and Demo modules that used the unsafe
143 interfaces have been updated to use the safe replacements. Thanks
144 to Zack Weinberg!
145
Guido van Rossumd81a9832002-08-09 15:57:34 +0000146- When x is an object whose class implements __mul__ and __rmul__,
147 1.0*x would correctly invoke __rmul__, but 1*x would erroneously
148 invoke __mul__. This was due to the sequence-repeat code in the int
149 type. This has been fixed now.
150
Barry Warsawd79f6832002-08-06 17:01:51 +0000151- Previously, "str1 in str2" required str1 to be a string of length 1.
152 This restriction has been relaxed to allow str1 to be a string of
153 any length. Thus "'el' in 'hello world'" returns True now.
154
Guido van Rossumb57089c2002-08-06 16:20:26 +0000155- File objects are now their own iterators. For a file f, iter(f) now
156 returns f (unless f is closed), and f.next() is similar to
157 f.readline() when EOF is not reached; however, f.next() uses a
158 readahead buffer that messes up the file position, so mixing
159 f.next() and f.readline() (or other methods) doesn't work right.
160 Calling f.seek() drops the readahead buffer, but other operations
161 don't. It so happens that this gives a nice additional speed boost
162 to "for line in file:"; the xreadlines method and corresponding
Guido van Rossumbffb2ef2002-08-09 17:17:07 +0000163 module are now obsolete. Thanks to Oren Tirosh!
Guido van Rossumb57089c2002-08-06 16:20:26 +0000164
Guido van Rossumde392d32002-08-05 14:17:20 +0000165- Encoding declarations (PEP 263, phase 1) have been implemented. A
166 comment of the form "# -*- coding: <encodingname> -*-" in the first
167 or second line of a Python source file indicates the encoding.
Martin v. Löwis00f1e3f2002-08-04 17:29:52 +0000168
Tim Petersf47630f2002-08-01 02:34:51 +0000169- list.sort() has a new implementation. While cross-platform results
170 may vary, and in data-dependent ways, this is much faster on many
171 kinds of partially ordered lists than the previous implementation,
172 and reported to be just as fast on randomly ordered lists on
173 several major platforms. This sort is also stable (if A==B and A
174 precedes B in the list at the start, A precedes B after the sort too),
175 although the language definition does not guarantee stability. A
176 potential drawback is that list.sort() may require temp space of
Skip Montanaroa2a07bc2002-09-30 15:23:01 +0000177 len(list)*2 bytes (``*4`` on a 64-bit machine). It's therefore possible
Tim Petersf47630f2002-08-01 02:34:51 +0000178 for list.sort() to raise MemoryError now, even if a comparison function
179 does not. See <http://www.python.org/sf/587076> for full details.
180
Guido van Rossum2d5389c2002-07-23 03:44:35 +0000181- All standard iterators now ensure that, once StopIteration has been
182 raised, all future calls to next() on the same iterator will also
183 raise StopIteration. There used to be various counterexamples to
184 this behavior, which could caused confusion or subtle program
185 breakage, without any benefits. (Note that this is still an
186 iterator's responsibility; the iterator framework does not enforce
187 this.)
188
Mark Hammondc0e35152002-07-16 01:32:30 +0000189- Ctrl+C handling on Windows has been made more consistent with
190 other platforms. KeyboardInterrupt can now reliably be caught,
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +0000191 and Ctrl+C at an interactive prompt no longer terminates the
Mark Hammondc0e35152002-07-16 01:32:30 +0000192 process under NT/2k/XP (it never did under Win9x). Ctrl+C will
Tim Peters5af4e6c2002-08-12 02:31:19 +0000193 interrupt time.sleep() in the main thread, and any child processes
194 created via the popen family (on win2k; we can't make win9x work
Mark Hammond8f3afc72002-08-10 06:26:31 +0000195 reliably) are also interrupted (as generally happens on for Linux/Unix.)
196 [SF bugs 231273, 439992 and 581232]
Mark Hammondc0e35152002-07-16 01:32:30 +0000197
Mark Hammond8696ebc2002-10-08 02:44:31 +0000198- sys.getwindowsversion() has been added on Windows. This
199 returns a tuple with information about the version of Windows
200 currently running.
201
Raymond Hettinger5a04aec2002-06-25 00:25:30 +0000202- Slices and repetitions of buffer objects now consistently return
203 a string. Formerly, strings would be returned most of the time,
204 but a buffer object would be returned when the repetition count
205 was one or when the slice range was all inclusive.
206
Walter Dörwald3430d702002-06-17 10:43:59 +0000207- Unicode objects in sys.path are no longer ignored but treated
208 as directory names.
209
Neal Norwitz1f68fc72002-06-14 00:50:42 +0000210- Fixed string.startswith and string.endswith builtin methods
211 so they accept negative indices. [SF bug 493951]
212
Guido van Rossumc5fe5eb2002-06-12 03:45:21 +0000213- Fixed a bug with a continue inside a try block and a yield in the
214 finally clause. [SF bug 567538]
215
Michael W. Hudson5efaf7e2002-06-11 10:55:12 +0000216- Most builtin sequences now support "extended slices", i.e. slices
Guido van Rossum2e82e712002-06-13 11:41:07 +0000217 with a third "stride" parameter. For example, "hello world"[::-1]
218 gives "dlrow olleh".
Michael W. Hudson5efaf7e2002-06-11 10:55:12 +0000219
Neal Norwitzd68f5172002-05-29 15:54:55 +0000220- A new warning PendingDeprecationWarning was added to provide
221 direction on features which are in the process of being deprecated.
222 The warning will not be printed by default. To see the pending
223 deprecations, use -Walways::PendingDeprecationWarning::
224 as a command line option or warnings.filterwarnings() in code.
225
Fred Draked0ba6362002-05-02 21:28:26 +0000226- Deprecated features of xrange objects have been removed as
227 promised. The start, stop, and step attributes and the tolist()
228 method no longer exist. xrange repetition and slicing have been
229 removed.
230
Guido van Rossum7dab2422002-04-26 19:40:56 +0000231- New builtin function enumerate(x), from PEP 279. Example:
232 enumerate("abc") is an iterator returning (0,"a"), (1,"b"), (2,"c").
233 The argument can be an arbitrary iterable object.
234
Neil Schemenauer89e3ee02002-04-26 01:58:53 +0000235- The assert statement no longer tests __debug__ at runtime. This means
236 that assert statements cannot be disabled by assigning a false value
237 to __debug__.
238
Walter Dörwald068325e2002-04-15 13:36:47 +0000239- A method zfill() was added to str and unicode, that fills a numeric
240 string to the left with zeros. For example,
241 "+123".zfill(6) -> "+00123".
242
Guido van Rossum862fe3c2002-04-15 12:36:47 +0000243- Complex numbers supported divmod() and the // and % operators, but
244 these make no sense. Since this was documented, they're being
245 deprecated now.
246
Guido van Rossum26dd8302002-04-26 20:11:29 +0000247- String and unicode methods lstrip(), rstrip() and strip() now take
248 an optional argument that specifies the characters to strip. For
249 example, "Foo!!!?!?!?".rstrip("?!") -> "Foo".
Guido van Rossum49042042002-04-13 00:59:05 +0000250
Guido van Rossumc69343b2002-04-12 19:22:48 +0000251- Added a new dict method pop(key). This removes and returns the
252 value corresponding to key. [SF patch #539949]
253
Guido van Rossum47834462002-04-04 15:21:33 +0000254- A new built-in type, bool, has been added, as well as built-in
255 names for its two values, True and False. Comparisons and sundry
256 other operations that return a truth value have been changed to
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000257 return a bool instead. Read PEP 285 for an explanation of why this
Guido van Rossum47834462002-04-04 15:21:33 +0000258 is backward compatible.
259
Guido van Rossum95b62a62002-03-29 01:07:24 +0000260- Fixed two bugs reported as SF #535905: under certain conditions,
261 deallocating a deeply nested structure could cause a segfault in the
262 garbage collector, due to interaction with the "trashcan" code;
263 access to the current frame during destruction of a local variable
264 could access a pointer to freed memory.
265
Guido van Rossumfe0ca4a2002-06-18 21:20:13 +0000266- The optional object allocator ("pymalloc") has been enabled by
267 default. The recommended practice for memory allocation and
268 deallocation has been streamlined. A header file is included,
269 Misc/pymemcompat.h, which can be bundled with 3rd party extensions
270 and lets them use the same API with Python versions from 1.5.2
271 onwards.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000272
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +0000273- PyErr_Display will provide file and line information for all exceptions
274 that have an attribute print_file_and_line, not just SyntaxErrors.
275
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000276- The UTF-8 codec will now encode and decode Unicode surrogates
277 correctly and without raising exceptions for unpaired ones.
278
Guido van Rossumadd88062002-08-15 14:01:14 +0000279- Universal newlines (PEP 278) is implemented. Briefly, using 'U'
280 instead of 'r' when opening a text file for reading changes the line
281 ending convention so that any of '\r', '\r\n', and '\n' is
282 recognized (even mixed in one file); all three are converted to
283 '\n', the standard Python line end character.
284
Neal Norwitz649b7592002-01-01 19:07:13 +0000285- file.xreadlines() now raises a ValueError if the file is closed:
286 Previously, an xreadlines object was returned which would raise
287 a ValueError when the xreadlines.next() method was called.
288
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000289- sys.exit() inadvertently allowed more than one argument.
Neal Norwitz0c766a02002-03-27 13:03:09 +0000290 An exception will now be raised if more than one argument is used.
291
Tim Petersaf8446f2001-12-21 21:36:50 +0000292Extension modules
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000293-----------------
Tim Petersaf8446f2001-12-21 21:36:50 +0000294
Martin v. Löwis080689c2002-10-26 14:42:02 +0000295- readline now dynamically adjusts its input/output stream if
296 sys.stdin/stdout changes.
297
Guido van Rossumba602972002-10-01 18:18:58 +0000298- The _tkinter module (and hence Tkinter) has dropped support for
299 Tcl/Tk 8.0 and 8.1. Only Tcl/Tk versions 8.2, 8.3 and 8.4 are
300 supported.
301
Martin v. Löwis658009a2002-09-16 17:26:24 +0000302- cPickle.BadPickleGet is now a class.
303
Martin v. Löwisa19bfe02002-10-16 18:28:36 +0000304- The time stamps in os.stat_result are floating point numbers
305 after stat_float_times has been called.
Martin v. Löwis94717ed2002-09-09 14:24:16 +0000306
Neal Norwitzb5673922002-09-05 21:48:07 +0000307- If the size passed to mmap.mmap() is larger than the length of the
308 file on non-Windows platforms, a ValueError is raised. [SF bug 585792]
309
Guido van Rossumb57089c2002-08-06 16:20:26 +0000310- The xreadlines module is slated for obsolescence.
311
Guido van Rossum79f0a102002-07-23 03:32:08 +0000312- The strptime function in the time module is now always available (a
313 Python implementation is used when the C library doesn't define it).
314
Guido van Rossum9562bcf2002-06-14 21:31:18 +0000315- The 'new' module is no longer an extension, but a Python module that
316 only exists for backwards compatibility. Its contents are no longer
317 functions but callable type objects.
318
Tim Peters81b92512002-04-29 01:37:32 +0000319- The bsddb.*open functions can now take 'None' as a filename.
Anthony Baxter83888952002-04-23 02:11:05 +0000320 This will create a temporary in-memory bsddb that won't be
Tim Peters81b92512002-04-29 01:37:32 +0000321 written to disk.
Anthony Baxter83888952002-04-23 02:11:05 +0000322
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000323- posix.lchown, posix.killpg, posix.mknod, and posix.getpgid have been
324 added where available.
Martin v. Löwis06a83e92002-04-14 10:19:44 +0000325
Martin v. Löwis2e64c342002-03-27 18:49:02 +0000326- The locale module now exposes the C library's gettext interface.
327
Tim Petersfbf74f22002-03-14 19:06:01 +0000328- A security hole ("double free") was found in zlib-1.1.3, a popular
329 third party compression library used by some Python modules. The
330 hole was quickly plugged in zlib-1.1.4, and the Windows build of
331 Python now ships with zlib-1.1.4.
332
Martin v. Löwis688357e2002-04-08 21:28:20 +0000333- pwd, grp, and resource return enhanced tuples now, with symbolic
334 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +0000335
Martin v. Löwis99866332002-03-01 10:27:01 +0000336- array.array is now a type object. A new format character
337 'u' indicates Py_UNICODE arrays. For those, .tounicode and
338 .fromunicode methods are available. Arrays now support __iadd__
339 and __imul__.
340
Neal Norwitze790eae2002-01-01 21:14:12 +0000341- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +0000342 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
343 is called.
344
Michael W. Hudson34f20ea2002-05-27 15:08:24 +0000345- signal.sigpending, signal.sigprocmask and signal.sigsuspend have
346 been added where available.
347
Skip Montanaro8e790e72002-09-03 13:25:17 +0000348- The sys module acquired a new attribute, api_version, which evaluates
349 to the value of the PYTHON_API_VERSION macro with which the
350 interpreter was compiled.
351
Tim Petersaf8446f2001-12-21 21:36:50 +0000352Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000353-------
Tim Petersaf8446f2001-12-21 21:36:50 +0000354
Martin v. Löwis74b51ac2002-10-26 14:50:45 +0000355- xml.sax.saxutils.unescape has been added, to replace entity references
356 with their entity value.
357
Martin v. Löwis77ac4292002-10-15 15:11:13 +0000358- Queue.Queue.{put,get} now support an optional timeout argument.
359
Martin v. Löwisb24e3472002-10-13 10:28:04 +0000360- Various features of Tk 8.4 are exposed in Tkinter.py. The multiple
361 option of tkFileDialog is exposed as function askopenfile{,name}s.
Martin v. Löwis2ec36272002-10-13 10:22:08 +0000362
Martin v. Löwisb24e3472002-10-13 10:28:04 +0000363- Various configure methods of Tkinter have been stream-lined, so that
364 tag_configure, image_configure, window_configure now return a
365 dictionary when invoked with no argument.
Martin v. Löwis6ce13152002-10-10 14:36:13 +0000366
Guido van Rossum2b492b62002-10-09 21:40:48 +0000367- Importing the readline module now no longer has the side effect of
368 calling setlocale(LC_CTYPE, ""). The initial "C" locale, or
369 whatever locale is explicitly set by the user, is preserved. If you
370 want repr() of 8-bit strings in your preferred encoding to preserve
371 all printable characters of that encoding, you have to add the
372 following code to your $PYTHONSTARTUP file or to your application's
373 main():
374
375 import locale
376 locale.setlocale(locale.LC_CTYPE, "")
377
Martin v. Löwise9ce0b02002-10-07 13:23:24 +0000378- shutil.move was added. shutil.copytree now reports errors as an
379 exception at the end, instead of printing error messages.
380
Marc-André Lemburg97047e22002-10-04 11:55:21 +0000381- Encoding name normalization was generalized to not only
382 replace hyphens with underscores, but also all other non-alphanumeric
383 characters (with the exception of the dot which is used for Python
384 package names during lookup). The aliases.py mapping was updated
385 to the new standard.
386
Walter Dörwald5ccaf8f2002-09-06 16:15:58 +0000387- mimetypes has two new functions: guess_all_extensions() which
388 returns a list of all known extensions for a mime type, and
389 add_type() which adds one mapping between a mime type and
390 an extension to the database.
391
Guido van Rossumd8ab35c2002-08-19 16:25:46 +0000392- New module: sets, defines the class Set that implements a mutable
393 set type using the keys of a dict to represent the set. There's
394 also a class ImmutableSet which is useful when you need sets of sets
395 or when you need to use sets as dict keys, and a class BaseSet which
396 is the base class of the two. (This is not documented yet, but
397 help(sets) gives a wealth of information.)
398
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +0000399- Added operator.pow(a,b) which is equivalent to a**b.
400
Tim Peters012c0a32002-08-16 03:40:07 +0000401- random.randrange(-sys.maxint-1, sys.maxint) no longer raises
402 OverflowError. That is, it now accepts any combination of 'start'
403 and 'stop' arguments so long as each is in the range of Python's
404 bounded integers.
405
Guido van Rossum4a57c332002-08-02 18:05:20 +0000406- New "algorithms" module: heapq, implements a heap queue. Thanks to
407 Kevin O'Connor for the code and François Pinard for an entertaining
408 write-up explaining the theory and practical uses of heaps.
409
Marc-André Lemburg58e2ff22002-07-12 14:40:04 +0000410- New encoding for the Palm OS character set: palmos.
411
Tim Peters943382c2002-07-07 03:59:34 +0000412- binascii.crc32() and the zipfile module had problems on some 64-bit
413 platforms. These have been fixed. On a platform with 8-byte C longs,
414 crc32() now returns a signed-extended 4-byte result, so that its value
415 as a Python int is equal to the value computed a 32-bit platform.
416
Martin v. Löwis7d650ca2002-06-30 15:05:00 +0000417- xml.dom.minidom.toxml and toprettyxml now take an optional encoding
418 argument.
419
Guido van Rossum9f7549b2002-06-10 21:39:42 +0000420- Some fixes in the copy module: when an object is copied through its
421 __reduce__ method, there was no check for a __setstate__ method on
422 the result [SF patch 565085]; deepcopy should treat instances of
423 custom metaclasses the same way it treats instances of type 'type'
424 [SF patch 560794].
425
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000426- Sockets now support timeout mode. After s.settimeout(T), where T is
427 a float expressing seconds, subsequent operations raise an exception
428 if they cannot be completed within T seconds. To disable timeout
Guido van Rossum79f0a102002-07-23 03:32:08 +0000429 mode, use s.settimeout(None). There's also a module function,
430 socket.setdefaulttimeout(T), which sets the default for all sockets
431 created henceforth.
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000432
433- getopt.gnu_getopt was added. This supports GNU-style option
434 processing, where options can be mixed with non-option arguments.
Martin v. Löwis446a25f2002-06-06 10:58:36 +0000435
Michael W. Hudsonb0dc1a32002-06-04 18:27:35 +0000436- Stop using strings for exceptions. String objects used for
437 exceptions are now classes deriving from Exception. The objects
438 changed were: Tkinter.TclError, bdb.BdbQuit, macpath.norm_error,
439 tabnanny.NannyNag, and xdrlib.Error.
Neal Norwitzb5b5a262002-06-04 17:14:07 +0000440
Walter Dörwald474458d2002-06-04 15:16:29 +0000441- Constants BOM_UTF8, BOM_UTF16, BOM_UTF16_LE, BOM_UTF16_BE,
442 BOM_UTF32, BOM_UTF32_LE and BOM_UTF32_BE that represent the Byte
443 Order Mark in UTF-8, UTF-16 and UTF-32 encodings for little and
444 big endian systems were added to the codecs module. The old names
445 BOM32_* and BOM64_* were off by a factor of 2.
446
Guido van Rossumf9257822002-06-18 20:43:18 +0000447- Added conversion functions math.degrees() and math.radians().
Raymond Hettinger87f59ee2002-05-13 04:17:32 +0000448
Raymond Hettinger9b1df1d2002-05-12 06:07:21 +0000449- ftplib.retrlines() now tests for callback is None rather than testing
450 for False. Was causing an error when given a callback object which
451 was callable but also returned len() as zero. The change may
452 create new breakage if the caller relied on the undocumented behavior
453 and called with callback set to [] or some other False value not
454 identical to None.
455
Tim Peters46c04e12002-05-05 20:40:00 +0000456- random.gauss() uses a piece of hidden state used by nothing else,
457 and the .seed() and .whseed() methods failed to reset it. In other
458 words, setting the seed didn't completely determine the sequence of
459 results produced by random.gauss(). It does now. Programs repeatedly
460 mixing calls to a seed method with calls to gauss() may see different
461 results now.
462
Fred Drake7f781c92002-05-01 20:33:53 +0000463- The pickle.Pickler class grew a clear_memo() method to mimic that
464 provided by cPickle.Pickler.
465
Tim Peters81b92512002-04-29 01:37:32 +0000466- difflib's SequenceMatcher class now does a dynamic analysis of
467 which elements are so frequent as to constitute noise. For
468 comparing files as sequences of lines, this generally works better
469 than the IS_LINE_JUNK function, and function ndiff's linejunk
470 argument defaults to None now as a result. A happy benefit is
471 that SequenceMatcher may run much faster now when applied
472 to large files with many duplicate lines (for example, C program
473 text with lots of repeated "}" and "return NULL;" lines).
474
Guido van Rossum256705b2002-04-23 13:29:43 +0000475- New Text.dump() method in Tkinter module.
476
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000477- New distutils commands for building packagers were added to
478 support pkgtool on Solaris and swinstall on HP-UX.
479
480- distutils now has a new abstract binary packager base class
481 command/bdist_packager, which simplifies writing packagers.
482 This will hopefully provide the missing bits to encourage
483 people to submit more packagers, e.g. for Debian, FreeBSD
484 and other systems.
485
Guido van Rossumf9257822002-06-18 20:43:18 +0000486- The UTF-16, -LE and -BE stream readers now raise a
487 NotImplementedError for all calls to .readline(). Previously, they
488 used to just produce garbage or fail with an encoding error --
489 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 +0000490 work well with these.
491
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000492- compileall now supports quiet operation.
493
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000494- The BaseHTTPServer now implements optional HTTP/1.1 persistent
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000495 connections.
496
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000497- socket module: the SSL support was broken out of the main
498 _socket module C helper and placed into a new _ssl helper
499 which now gets imported by socket.py if available and working.
500
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000501- encodings package: added aliases for all supported IANA character
502 sets
503
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000504- ftplib: to safeguard the user's privacy, anonymous login will use
505 "anonymous@" as default password, rather than the real user and host
506 name.
507
Fred Drake36736122002-01-10 13:50:31 +0000508- webbrowser: tightened up the command passed to os.system() so that
509 arbitrary shell code can't be executed because a bogus URL was
510 passed in.
511
Tim Peters11bd9942002-02-01 00:52:29 +0000512- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000513 gettext.find an optional all argument. Translations will now fallback
514 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000515
Martin v. Löwis9668b932002-01-12 11:27:42 +0000516- distutils bdist commands now offer a --skip-build option.
517
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000518- warnings.warn now accepts a Warning instance as first argument.
519
Fred Drakefed7e852002-04-04 19:36:15 +0000520- The xml.sax.expatreader.ExpatParser class will no longer create
521 circular references by using itself as the locator that gets passed
522 to the content handler implementation. [SF bug #535474]
523
Barry Warsaw47f3e2c2002-05-20 00:14:24 +0000524- The email.Parser.Parser class now properly parses strings regardless
525 of their line endings, which can be any of \r, \n, or \r\n (CR, LF,
526 or CRLF). Also, the Header class's constructor default arguments
527 has changed slightly so that an explicit maxlinelen value is always
528 honored.
529
Tim Petersaf8446f2001-12-21 21:36:50 +0000530Tools/Demos
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000531-----------
Tim Petersaf8446f2001-12-21 21:36:50 +0000532
Guido van Rossum923e4ef2002-09-17 20:58:59 +0000533- The SGI demos (Demo/sgi) have been removed. Nobody thought they
534 were interesting any more. (The SGI library modules and extensions
535 are still there; it is believed that at least some of these are
536 still used and useful.)
537
Fred Drake40813b12002-08-05 15:24:19 +0000538- IDLE supports the new encoding declarations (PEP 263); it can also
539 deal with legacy 8-bit files if they use the locale's encoding. It
540 allows non-ASCII strings in the interactive shell and executes them
541 in the locale's encoding.
Martin v. Löwis98ce7b72002-08-05 15:11:26 +0000542
Marc-André Lemburg46260092002-04-04 16:17:11 +0000543- freeze.py now produces binaries which can import shared modules,
544 unlike before when this failed due to missing symbol exports in
545 the generated binary.
546
Tim Petersaf8446f2001-12-21 21:36:50 +0000547Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000548-----
Tim Petersaf8446f2001-12-21 21:36:50 +0000549
Guido van Rossum6b3db552002-09-25 15:02:44 +0000550- The fpectl module is not built by default; it's dangerous or useless
551 except in the hands of experts.
552
Tim Petersf47630f2002-08-01 02:34:51 +0000553- The public Python C API will generally be declared using PyAPI_FUNC
Guido van Rossum6b3db552002-09-25 15:02:44 +0000554 and PyAPI_DATA macros, while Python extension module init functions
555 will be declared with PyMODINIT_FUNC. DL_EXPORT/DL_IMPORT macros
556 are deprecated.
Neal Norwitz1389f3e2002-07-22 13:21:10 +0000557
Tim Petersc6a3ff62002-07-08 22:11:52 +0000558- A bug was fixed that could cause COUNT_ALLOCS builds to segfault, or
559 get into infinite loops, when a new-style class got garbage-collected.
560 Unfortunately, to avoid this, the way COUNT_ALLOCS works requires
561 that new-style classes be immortal in COUNT_ALLOCS builds. Note that
562 COUNT_ALLOCS is not enabled by default, in either release or debug
563 builds, and that new-style classes are immortal only in COUNT_ALLOCS
564 builds.
565
Tim Peters943382c2002-07-07 03:59:34 +0000566- Compiling out the cyclic garbage collector is no longer an option.
567 The old symbol WITH_CYCLE_GC is now ignored, and Python.h arranges
568 that it's always defined (for the benefit of any extension modules
569 that may be conditionalizing on it). A bonus is that any extension
570 type participating in cyclic gc can choose to participate in the
571 Py_TRASHCAN mechanism now too; in the absence of cyclic gc, this used
572 to require editing the core to teach the trashcan mechanism about the
573 new type.
574
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000575- According to Annex F of the current C standard,
Tim Peters1de41bf2002-07-03 03:31:20 +0000576
577 The Standard C macro HUGE_VAL and its float and long double analogs,
578 HUGE_VALF and HUGE_VALL, expand to expressions whose values are
579 positive infinities.
580
581 Python only uses the double HUGE_VAL, and only to #define its own symbol
582 Py_HUGE_VAL. Some platforms have incorrect definitions for HUGE_VAL.
583 pyport.h used to try to worm around that, but the workarounds triggered
584 other bugs on other platforms, so we gave up. If your platform defines
585 HUGE_VAL incorrectly, you'll need to #define Py_HUGE_VAL to something
586 that works on your platform. The only instance of this I'm sure about
587 is on an unknown subset of Cray systems, described here:
588
589 http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm
590
591 Presumably 2.3a1 breaks such systems. If anyone uses such a system, help!
592
Martin v. Löwisa3fb4f72002-06-09 13:33:54 +0000593- The configure option --without-doc-strings can be used to remove the
594 doc strings from the builtin functions and modules; this reduces the
595 size of the executable.
596
Guido van Rossumadd88062002-08-15 14:01:14 +0000597- The universal newlines option (PEP 278) is on by default. On Unix
598 it can be disabled by passing --without-universal-newlines to the
599 configure script. On other platforms, remove
600 WITH_UNIVERSAL_NEWLINES from pyconfig.h.
Tim Peters639295f2002-04-21 07:30:30 +0000601
Martin v. Löwis1142de32002-03-29 16:28:31 +0000602- On Unix, a shared libpython2.3.so can be created with --enable-shared.
603
Tim Peters8deda702002-03-30 10:06:07 +0000604- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
605 preprocessor symbols were eliminated. The internal decisions they
606 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000607
Fred Drake7d28b732002-05-02 21:17:00 +0000608- The tools used to build the documentation now work under Cygwin as
609 well as Unix.
610
Skip Montanaro57454e52002-06-14 20:30:31 +0000611- The bsddb and dbm module builds have been changed to try and avoid version
612 skew problems and disable linkage with Berkeley DB 1.85 unless the
613 installer knows what s/he's doing. See the section on building these
614 modules in the README file for details.
615
Tim Petersaf8446f2001-12-21 21:36:50 +0000616C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000617-----
Tim Petersaf8446f2001-12-21 21:36:50 +0000618
Guido van Rossum45ec02a2002-08-19 21:43:18 +0000619- The string object's layout has changed: the pointer member
620 ob_sinterned has been replaced by an int member ob_sstate. On some
621 platforms (e.g. most 64-bit systems) this may change the offset of
622 the ob_sval member, so as a precaution the API_VERSION has been
623 incremented. The apparently unused feature of "indirect interned
624 strings", supported by the ob_sinterned member, is gone. Interned
625 strings are now usually mortal; theres a new API,
626 PyString_InternImmortal() that creates immortal interned strings.
627 (The ob_sstate member can only take three values; however, while
628 making it a char saves a few bytes per string object on average, in
629 it also slowed things down a bit because ob_sval was no longer
630 aligned.)
631
Guido van Rossumfdb86482002-08-14 21:20:32 +0000632- The Py_InitModule*() functions now accept NULL for the 'methods'
633 argument. Modules without global functions are becoming more common
634 now that factories can be types rather than functions.
635
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +0000636- New C API PyUnicode_FromOrdinal() which exposes unichr() at C
637 level.
638
Thomas Heller085358a2002-07-29 14:27:41 +0000639- New functions PyErr_SetExcFromWindowsErr() and
640 PyErr_SetExcFromWindowsErrWithFilename(). Similar to
641 PyErr_SetFromWindowsErrWithFilename() and
642 PyErr_SetFromWindowsErr(), but they allow to specify
643 the exception type to raise. Available on Windows.
644
Tim Peters7c321a82002-07-09 02:57:01 +0000645- Py_FatalError() is now declared as taking a const char* argument. It
646 was previously declared without const. This should not affect working
647 code.
648
Martin v. Löwis01f94bd2002-05-08 08:44:21 +0000649- Added new macro PySequence_ITEM(o, i) that directly calls
650 sq_item without rechecking that o is a sequence and without
651 adjusting for negative indices.
652
Fred Draked0ba6362002-05-02 21:28:26 +0000653- PyRange_New() now raises ValueError if the fourth argument is not 1.
654 This is part of the removal of deprecated features of the xrange
655 object.
656
Guido van Rossum517c7d42002-04-26 02:49:14 +0000657- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
658 coercion if both arguments have the same type but this type has the
659 CHECKTYPES flag set. This is to better support proxies.
660
Skip Montanaroa2a07bc2002-09-30 15:23:01 +0000661- The type of tp_free has been changed from "``void (*)(PyObject *)``" to
662 "``void (*)(void *)``".
Neil Schemenauer9344b142002-04-12 23:00:08 +0000663
664- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
665
Guido van Rossum0986d822002-04-08 01:38:42 +0000666- A type can now inherit its metatype from its base type. Previously,
667 when PyType_Ready() was called, if ob_type was found to be NULL, it
668 was always set to &PyType_Type; now it is set to base->ob_type,
669 where base is tp_base, defaulting to &PyObject_Type.
670
671- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
672
Neil Schemenauerc9abc1d2002-05-08 14:14:41 +0000673- The PyCore_* family of APIs have been removed.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000674
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000675- The "u#" parser marker will now pass through Unicode objects as-is
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000676 without going through the buffer API.
677
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000678- The enumerators of cmp_op have been renamed to use the prefix ``PyCmp_``.
Martin v. Löwis7198a522002-01-01 19:59:11 +0000679
Tim Peters10a3bb52001-12-25 19:07:38 +0000680- An old #define of ANY as void has been removed from pyport.h. This
681 hasn't been used since Python's pre-ANSI days, and the #define has
682 been marked as obsolete since then. SF bug 495548 says it created
683 conflicts with other packages, so keeping it around wasn't harmless.
684
Tim Petersaf8446f2001-12-21 21:36:50 +0000685- Because Python's magic number scheme broke on January 1st, we decided
686 to stop Python development. Thanks for all the fish!
687
Tim Petersfb05db22002-03-11 00:24:00 +0000688- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000689 scheme to a new one. See Python/import.c for details.
690
Tim Petersaf8446f2001-12-21 21:36:50 +0000691New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000692-------------
Tim Petersaf8446f2001-12-21 21:36:50 +0000693
Martin v. Löwisf90ae202002-06-11 06:22:31 +0000694- AtheOS is now supported.
695
Andrew MacIntyre161ad0e2002-08-04 07:25:58 +0000696- the EMX runtime environment on OS/2 is now supported.
697
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000698- GNU/Hurd is now supported.
699
Tim Petersaf8446f2001-12-21 21:36:50 +0000700Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000701-----
702
703Yet to be written.
Tim Petersaf8446f2001-12-21 21:36:50 +0000704
705Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000706-------
Tim Petersaf8446f2001-12-21 21:36:50 +0000707
Tim Peters08e72952002-04-16 20:48:01 +0000708- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
709 of that has been fixed in the installer (disabled Wise's "delete in-
710 use files" uninstall option).
711
Guido van Rossum181e41a2002-04-06 00:23:25 +0000712- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
713
Tim Peters33187922002-04-04 20:02:04 +0000714- The installer now installs Start menu shortcuts under (the local
715 equivalent of) "All Users" when doing an Admin install.
716
Tim Petersfb05db22002-03-11 00:24:00 +0000717- file.truncate([newsize]) now works on Windows for all newsize values.
718 It used to fail if newsize didn't fit in 32 bits, reflecting a
719 limitation of MS _chsize (which is no longer used).
720
Tim Petersab034fa2002-02-01 11:27:43 +0000721- os.waitpid() is now implemented for Windows, and can be used to block
722 until a specified process exits. This is similar to, but not exactly
723 the same as, os.waitpid() on POSIX systems. If you're waiting for
724 a specific process whose pid was obtained from one of the spawn()
725 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000726 See the docs for details. The docs were changed to clarify that
727 spawn functions return, and waitpid requires, a process handle on
728 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000729
Tim Peters11bd9942002-02-01 00:52:29 +0000730- New tempfile.TemporaryFile implementation for Windows: this doesn't
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000731 need a TemporaryFileWrapper wrapper anymore, and should be immune
Tim Peters11bd9942002-02-01 00:52:29 +0000732 to a nasty problem: before 2.3, if you got a temp file on Windows, it
733 got wrapped in an object whose close() method first closed the
734 underlying file, then deleted the file. This usually worked fine.
735 However, the spawn family of functions on Windows create (at a low C
736 level) the same set of open files in the spawned process Q as were
737 open in the spawning process P. If a temp file f was among them, then
738 doing f.close() in P first closed P's C-level file handle on f, but Q's
739 C-level file handle on f remained open, so the attempt in P to delete f
740 blew up with a "Permission denied" error (Windows doesn't allow
741 deleting open files). This was surprising, subtle, and difficult to
742 work around.
743
744- The os module now exports all the symbolic constants usable with the
745 low-level os.open() on Windows: the new constants in 2.3 are
746 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
747 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
748 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
749 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
750 (so specify both if you want both; note that neither is useful unless
751 specified with O_CREAT too).
752
Tim Petersaf8446f2001-12-21 21:36:50 +0000753Mac
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000754----
755
756Yet to be written.
Tim Petersaf8446f2001-12-21 21:36:50 +0000757
758
Tim Peters909c0912001-12-14 23:16:18 +0000759What's New in Python 2.2 final?
Tim Peters909c0912001-12-14 23:16:18 +0000760===============================
761
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000762*Release date: 21-Dec-2001*
763
Tim Peters909c0912001-12-14 23:16:18 +0000764Type/class unification and new-style classes
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000765--------------------------------------------
Tim Peters909c0912001-12-14 23:16:18 +0000766
Barry Warsaw52acb492001-12-21 20:04:22 +0000767- pickle.py, cPickle: allow pickling instances of new-style classes
768 with a custom metaclass.
769
Tim Peters909c0912001-12-14 23:16:18 +0000770Core and builtins
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000771-----------------
Tim Peters909c0912001-12-14 23:16:18 +0000772
Barry Warsaw52acb492001-12-21 20:04:22 +0000773- weakref proxy object: when comparing, unwrap both arguments if both
774 are proxies.
775
Tim Peters909c0912001-12-14 23:16:18 +0000776Extension modules
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000777-----------------
Tim Peters909c0912001-12-14 23:16:18 +0000778
Barry Warsaw52acb492001-12-21 20:04:22 +0000779- binascii.b2a_base64(): fix a potential buffer overrun when encoding
780 very short strings.
781
782- cPickle: the obscure "fast" mode was suspected of causing stack
783 overflows on the Mac. Hopefully fixed this by setting the recursion
784 limit much smaller. If the limit is too low (it only affects
785 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
786 when compiling cPickle.c (or in pyconfig.h).
787
Tim Peters909c0912001-12-14 23:16:18 +0000788Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000789-------
Tim Peters909c0912001-12-14 23:16:18 +0000790
Barry Warsaw52acb492001-12-21 20:04:22 +0000791- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
792 close or delete time).
793
794- rfc822.py: fixed a bug where the address '<>' was converted to None
795 instead of an empty string (also fixes the email.Utils module).
796
797- xmlrpclib.py: version 1.0.0; uses precision for doubles.
798
799- test suite: the pickle and cPickle tests were not executing any code
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000800 when run from the standard regression test.
Barry Warsaw52acb492001-12-21 20:04:22 +0000801
Tim Peters909c0912001-12-14 23:16:18 +0000802Tools/Demos
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000803-----------
Tim Peters909c0912001-12-14 23:16:18 +0000804
805Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000806-----
Tim Peters909c0912001-12-14 23:16:18 +0000807
808C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000809-----
Tim Peters909c0912001-12-14 23:16:18 +0000810
811New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000812-------------
Tim Peters909c0912001-12-14 23:16:18 +0000813
814Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000815-----
Tim Peters909c0912001-12-14 23:16:18 +0000816
817Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000818-------
Tim Peters909c0912001-12-14 23:16:18 +0000819
Barry Warsaw52acb492001-12-21 20:04:22 +0000820- distutils package: fixed broken Windows installers (bdist_wininst).
821
822- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
823 instances are deleted at process exit time.
824
825- socket.py: prevent mysterious warnings when socket instances are
826 deleted at process exit time.
827
828- posixmodule.c: fix a Windows crash with stat() of a filename ending
829 in backslash.
830
Tim Peters909c0912001-12-14 23:16:18 +0000831Mac
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000832----
Tim Peters909c0912001-12-14 23:16:18 +0000833
Barry Warsaw52acb492001-12-21 20:04:22 +0000834- The Carbon toolbox modules have been upgraded to Universal Headers
835 3.4, and experimental CoreGraphics and CarbonEvents modules have
836 been added. All only for framework-enabled MacOSX.
837
Tim Peters909c0912001-12-14 23:16:18 +0000838
Tim Peters6272dfd2001-12-13 19:34:00 +0000839What's New in Python 2.2c1?
Tim Petersb3c9af12001-11-17 00:21:57 +0000840===========================
841
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000842*Release date: 14-Dec-2001*
843
Tim Petersb3c9af12001-11-17 00:21:57 +0000844Type/class unification and new-style classes
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000845--------------------------------------------
Tim Petersb3c9af12001-11-17 00:21:57 +0000846
Barry Warsaw06557452001-12-14 20:47:12 +0000847- Guido's tutorial introduction to the new type/class features has
848 been extensively updated. See
849
850 http://www.python.org/2.2/descrintro.html
851
852 That remains the primary documentation in this area.
853
Guido van Rossum33bab012001-12-05 22:45:48 +0000854- Fixed a leak: instance variables declared with __slots__ were never
855 deleted!
856
Guido van Rossum4b800852001-12-03 00:54:52 +0000857- The "delete attribute" method of descriptor objects is called
858 __delete__, not __del__. In previous releases, it was mistakenly
859 called __del__, which created an unfortunate overloading condition
860 with finalizers. (The "get attribute" and "set attribute" methods
861 are still called __get__ and __set__, respectively.)
862
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000863- Some subtle issues with the super built-in were fixed:
864
865 (a) When super itself is subclassed, its __get__ method would still
866 return an instance of the base class (i.e., of super).
867
868 (b) super(C, C()).__class__ would return C rather than super. This
869 is confusing. To fix this, I decided to change the semantics of
870 super so that it only applies to code attributes, not to data
871 attributes. After all, overriding data attributes is not
872 supported anyway.
873
874 (c) The __get__ method didn't check whether the argument was an
875 instance of the type used in creation of the super instance.
876
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000877- Previously, hash() of an instance of a subclass of a mutable type
878 (list or dictionary) would return some value, rather than raising
879 TypeError. This has been fixed. Also, directly calling
880 dict.__hash__ and list.__hash__ now raises the same TypeError
881 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000882
Guido van Rossumd331cb52001-12-05 19:46:42 +0000883- New-style objects now support deleting their __dict__. This is for
884 all intents and purposes equivalent to assigning a brand new empty
885 dictionary, but saves space if the object is not used further.
886
Tim Petersb3c9af12001-11-17 00:21:57 +0000887Core and builtins
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000888-----------------
Tim Petersb3c9af12001-11-17 00:21:57 +0000889
Tim Peters3caca232001-12-06 06:23:26 +0000890- -Qnew now works as documented in PEP 238: when -Qnew is passed on
891 the command line, all occurrences of "/" use true division instead
892 of classic division. See the PEP for details. Note that "all"
893 means all instances in library and 3rd-party modules, as well as in
894 your own code. As the PEP says, -Qnew is intended for use only in
895 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000896 Note that test_coercion.py in the standard Python test suite fails
897 under -Qnew; this is expected, and won't be repaired until true
898 division becomes the default (in the meantime, test_coercion is
899 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000900
Fred Drake6c01e252001-12-14 17:08:12 +0000901- complex() now only allows the first argument to be a string
902 argument, and raises TypeError if either the second arg is a string
903 or if the second arg is specified when the first is a string.
904
Tim Petersb3c9af12001-11-17 00:21:57 +0000905Extension modules
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000906-----------------
Tim Petersb3c9af12001-11-17 00:21:57 +0000907
Martin v. Löwis560da622001-11-24 09:24:51 +0000908- gc.get_referents was renamed to gc.get_referrers.
909
Tim Petersb3c9af12001-11-17 00:21:57 +0000910Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000911-------
Tim Petersb3c9af12001-11-17 00:21:57 +0000912
Tim Peters25059d32001-12-07 20:35:43 +0000913- Functions in the os.spawn() family now release the global interpreter
914 lock around calling the platform spawn. They should always have done
915 this, but did not before 2.2c1. Multithreaded programs calling
916 an os.spawn function with P_WAIT will no longer block all Python threads
917 until the spawned program completes. It's possible that some programs
918 relies on blocking, although more likely by accident than by design.
919
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000920- webbrowser defaults to netscape.exe on OS/2 now.
921
Martin v. Löwis652e1912001-11-25 14:50:56 +0000922- Tix.ResizeHandle exposes detach_widget, hide, and show.
923
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000924- The charset alias windows_1252 has been added.
925
Barry Warsaw06557452001-12-14 20:47:12 +0000926- types.StringTypes is a tuple containing the defined string types;
927 usually this will be (str, unicode), but if Python was compiled
928 without Unicode support it will be just (str,).
929
930- The pulldom and minidom modules were synchronized to PyXML.
931
Tim Petersb3c9af12001-11-17 00:21:57 +0000932Tools/Demos
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000933-----------
Tim Petersb3c9af12001-11-17 00:21:57 +0000934
Barry Warsaw06557452001-12-14 20:47:12 +0000935- A new script called Tools/scripts/google.py was added, which fires
936 off a search on Google.
937
Tim Petersb3c9af12001-11-17 00:21:57 +0000938Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000939-----
Tim Petersb3c9af12001-11-17 00:21:57 +0000940
Barry Warsaw06557452001-12-14 20:47:12 +0000941- Note that release builds of Python should arrange to define the
942 preprocessor symbol NDEBUG on the command line (or equivalent).
943 In the 2.2 pre-release series we tried to define this by magic in
944 Python.h instead, but it proved to cause problems for extension
945 authors. The Unix, Windows and Mac builds now all define NDEBUG in
946 release builds via cmdline (or equivalent) instead. Ports to
947 other platforms should do likewise.
948
Jack Jansen1999ef42001-12-06 21:47:20 +0000949- It is no longer necessary to use --with-suffix when building on a
950 case-insensitive file system (such as Mac OS X HFS+). In the build
951 directory an extension is used, but not in the installed python.
952
Tim Petersb3c9af12001-11-17 00:21:57 +0000953C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000954-----
Tim Petersb3c9af12001-11-17 00:21:57 +0000955
Tim Petersf582b822001-12-11 18:51:08 +0000956- New function PyDict_MergeFromSeq2() exposes the builtin dict
957 constructor's logic for updating a dictionary from an iterable object
958 producing key-value pairs.
959
Tim Peterscffed4b2001-11-29 03:26:37 +0000960- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000961 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000962 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
963 dump core in some bad cases. This has been repaired. As a result,
964 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
965 previously went unchallenged.
966
Tim Petersb3c9af12001-11-17 00:21:57 +0000967New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000968-------------
Tim Petersb3c9af12001-11-17 00:21:57 +0000969
970Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000971-----
Tim Petersb3c9af12001-11-17 00:21:57 +0000972
973Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000974-------
Tim Petersb3c9af12001-11-17 00:21:57 +0000975
976Mac
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000977----
Tim Petersb3c9af12001-11-17 00:21:57 +0000978
Jack Jansenffa260f2001-12-06 21:14:00 +0000979- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
980 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000981
Barry Warsaw06557452001-12-14 20:47:12 +0000982- Changed logic for finding python home in Mac OS X framework Pythons.
983 Now sys.executable points to the executable again, in stead of to
984 the shared library. The latter is used only for locating the python
985 home.
986
987
Tim Peters84362bc2001-10-19 17:55:30 +0000988What's New in Python 2.2b2?
Tim Peters84362bc2001-10-19 17:55:30 +0000989===========================
990
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000991*Release date: 16-Nov-2001*
992
Tim Peters84362bc2001-10-19 17:55:30 +0000993Type/class unification and new-style classes
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000994--------------------------------------------
Tim Peters84362bc2001-10-19 17:55:30 +0000995
Guido van Rossum3d27df02001-11-15 20:27:54 +0000996- Multiple inheritance mixing new-style and classic classes in the
997 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000998
999 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +00001000 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +00001001
1002 The MRO (method resolution order) for each base class is respected
1003 according to its kind, but the MRO for the derived class is computed
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001004 using new-style MRO rules if any base class is a new-style class.
Tim Peters76f7fe32001-11-15 20:02:21 +00001005 This needs to be documented.
1006
Tim Petersa427a2b2001-10-29 22:25:45 +00001007- The new builtin dictionary() constructor, and dictionary type, have
1008 been renamed to dict. This reflects a decade of common usage.
1009
Guido van Rossum3fc08d22001-11-15 20:33:10 +00001010- dict() now accepts an iterable object producing 2-sequences. For
1011 example, dict(d.items()) == d for any dictionary d. The argument,
1012 and the elements of the argument, can be any iterable objects.
1013
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +00001014- New-style classes can now have a __del__ method, which is called
1015 when the instance is deleted (just like for classic classes).
1016
Guido van Rossum12d955c2001-10-26 14:56:06 +00001017- Assignment to object.__dict__ is now possible, for objects that are
1018 instances of new-style classes that have a __dict__ (unless the base
1019 class forbids it).
1020
Guido van Rossumc8e56452001-10-22 00:43:43 +00001021- Methods of built-in types now properly check for keyword arguments
1022 (formerly these were silently ignored). The only built-in methods
1023 that take keyword arguments are __call__, __init__ and __new__.
1024
Guido van Rossum86443212001-10-27 22:28:54 +00001025- The socket function has been converted to a type; see below.
1026
Tim Peters84362bc2001-10-19 17:55:30 +00001027Core and builtins
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001028-----------------
Tim Peters84362bc2001-10-19 17:55:30 +00001029
Jeremy Hylton249aaed2001-11-09 21:06:24 +00001030- Assignment to __debug__ raises SyntaxError at compile-time. This
1031 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +00001032 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +00001033
Guido van Rossum12d955c2001-10-26 14:56:06 +00001034- Clarified the error messages for unsupported operands to an operator
1035 (like 1 + '').
1036
Tim Peters84362bc2001-10-19 17:55:30 +00001037Extension modules
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001038-----------------
Tim Peters84362bc2001-10-19 17:55:30 +00001039
Tim Peters5ebfd362001-11-13 23:11:19 +00001040- mmap has a new keyword argument, "access", allowing a uniform way for
1041 both Windows and Unix users to create read-only, write-through and
1042 copy-on-write memory mappings. This was previously possible only on
1043 Unix. A new keyword argument was required to support this in a
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001044 uniform way because the mmap() signatures had diverged across
Tim Peters5ebfd362001-11-13 23:11:19 +00001045 platforms. Thanks to Jay T Miller for repairing this!
1046
Tim Peters169ded02001-11-03 19:57:21 +00001047- By default, the gc.garbage list now contains only those instances in
1048 unreachable cycles that have __del__ methods; in 2.1 it contained all
1049 instances in unreachable cycles. "Instances" here has been generalized
1050 to include instances of both new-style and old-style classes.
1051
Guido van Rossum12d955c2001-10-26 14:56:06 +00001052- The socket module defines a new method for socket objects,
1053 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +00001054 send() until all data has been sent. Also, the socket function has
1055 been converted to a subclassable type, like list and tuple (etc.)
1056 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +00001057
1058- Various bugfixes to the curses module. There is now a test suite
1059 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +00001060
Guido van Rossum692adf12001-10-30 03:03:03 +00001061- binascii.b2a_base64 no longer places an arbitrary restriction of 57
1062 bytes on its input.
1063
Tim Peters84362bc2001-10-19 17:55:30 +00001064Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001065-------
Tim Peters84362bc2001-10-19 17:55:30 +00001066
Tim Peters5ebfd362001-11-13 23:11:19 +00001067- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +00001068 convenience function.
1069
Tim Peters75335872001-11-03 19:35:43 +00001070- Symbolic group names in regular expressions must be unique. For
1071 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
1072 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +00001073 Python 2.2 detects this error at regexp compilation time;
1074 previously, the error went undetected, and results were
1075 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
1076 pattern.subn() methods have been rewritten in C. Also, an
1077 experimental function/method finditer() has been added, which works
1078 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +00001079
Martin v. Löwisb7b32602001-11-02 23:48:20 +00001080- Tix exposes more commands through the classes DirSelectBox,
1081 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
1082 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
1083 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
1084
Tim Peters98791af2001-10-23 01:59:54 +00001085- Traceback objects are now scanned by cyclic garbage collection, so
1086 cycles created by casual use of sys.exc_info() no longer cause
1087 permanent memory leaks (provided garbage collection is enabled).
1088
Guido van Rossum49192142001-10-24 20:51:44 +00001089- os.extsep -- a new variable needed by the RISCOS support. It is the
1090 separator used by extensions, and is '.' on all platforms except
1091 RISCOS, where it is '/'. There is no need to use this variable
1092 unless you have a masochistic desire to port your code to RISCOS.
1093
Barry Warsaw012852b2001-11-16 16:17:27 +00001094- mimetypes.py has optional support for non-standard, but commonly
1095 found types. guess_type() and guess_extension() now accept an
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001096 optional 'strict' flag, defaulting to true, which controls whether
Barry Warsaw012852b2001-11-16 16:17:27 +00001097 recognize non-standard types or not. A few non-standard types we
1098 know about have been added. Also, when run as a script, there are
1099 new -l and -e options.
1100
1101- statcache is now deprecated.
1102
1103- email.Utils.formatdate() now produces the preferred RFC 2822 style
1104 dates with numeric timezones (it used to produce obsolete dates
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001105 hard coded to "GMT" timezone). An optional 'localtime' flag is
Barry Warsaw012852b2001-11-16 16:17:27 +00001106 added to produce dates in the local timezone, with daylight savings
1107 time properly taken into account.
1108
1109- In pickle and cPickle, instead of masking errors in load() by
1110 transforming them into SystemError, we let the original exception
1111 propagate out. Also, implement support for __safe_for_unpickling__
1112 in pickle, as it already was supported in cPickle.
1113
Tim Peters84362bc2001-10-19 17:55:30 +00001114Tools/Demos
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001115-----------
Tim Peters84362bc2001-10-19 17:55:30 +00001116
1117Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001118-----
Tim Peters84362bc2001-10-19 17:55:30 +00001119
Barry Warsaw012852b2001-11-16 16:17:27 +00001120- The dbm module is built using libdb1 if available. The bsddb module
1121 is built with libdb3 if available.
1122
1123- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
1124
Tim Peters84362bc2001-10-19 17:55:30 +00001125C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001126-----
Tim Peters84362bc2001-10-19 17:55:30 +00001127
Tim Peters1fc240e2001-10-26 05:06:50 +00001128- New function PySequence_Fast_GET_SIZE() returns the size of a non-
1129 NULL result from PySequence_Fast(), more quickly than calling
1130 PySequence_Size().
1131
Barry Warsaw012852b2001-11-16 16:17:27 +00001132- New argument unpacking function PyArg_UnpackTuple() added.
1133
1134- New functions PyObject_CallFunctionObjArgs() and
1135 PyObject_CallMethodObjArgs() have been added to make it more
1136 convenient and efficient to call functions and methods from C.
1137
1138- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
1139 possible that this will propagate errors it didn't before.
1140
1141- New function PyObject_CheckReadBuffer(), which returns true if its
1142 argument supports the single-segment readable buffer interface.
1143
Tim Peters84362bc2001-10-19 17:55:30 +00001144New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001145-------------
Tim Peters84362bc2001-10-19 17:55:30 +00001146
Guido van Rossum86443212001-10-27 22:28:54 +00001147- We've finally confirmed that this release builds on HP-UX 11.00,
1148 *with* threads, and passes the test suite.
1149
Tim Peters7a33d8b2001-11-05 02:51:07 +00001150- Thanks to a series of patches from Michael Muller, Python may build
1151 again under OS/2 Visual Age C++.
1152
Guido van Rossum49192142001-10-24 20:51:44 +00001153- Updated RISCOS port by Dietmar Schwertberger.
1154
Tim Peters84362bc2001-10-19 17:55:30 +00001155Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001156-----
Tim Peters84362bc2001-10-19 17:55:30 +00001157
Andrew M. Kuchling15e03532001-10-22 16:37:10 +00001158- Added a test script for the curses module. It isn't run automatically;
1159 regrtest.py must be run with '-u curses' to enable it.
1160
Tim Peters84362bc2001-10-19 17:55:30 +00001161Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001162-------
Tim Peters84362bc2001-10-19 17:55:30 +00001163
Barry Warsaw012852b2001-11-16 16:17:27 +00001164Mac
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001165----
Barry Warsaw012852b2001-11-16 16:17:27 +00001166
1167- PythonScript has been moved to unsupported and is slated to be
1168 removed completely in the next release.
1169
1170- It should now be possible to build applets that work on both OS9 and
1171 OSX.
1172
1173- The core is now linked with CoreServices not Carbon; as a side
1174 result, default 8bit encoding on OSX is now ASCII.
1175
1176- Python should now build on OSX 10.1.1
1177
Tim Peters84362bc2001-10-19 17:55:30 +00001178
Tim Petersabf925f2001-09-28 21:53:42 +00001179What's New in Python 2.2b1?
Tim Petersabf925f2001-09-28 21:53:42 +00001180===========================
1181
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001182*Release date: 19-Oct-2001*
1183
Tim Petersabf925f2001-09-28 21:53:42 +00001184Type/class unification and new-style classes
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001185--------------------------------------------
Tim Petersabf925f2001-09-28 21:53:42 +00001186
Guido van Rossum687ae002001-10-15 22:03:32 +00001187- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001188 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +00001189 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001190 remains: the __dict__ of a new-style class is a read-only proxy; you
1191 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +00001192 __defined__ attribute of new-style types no longer exists, for lack
1193 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001194 future a __cache__ may be resurrected with a similar function, if I
1195 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +00001196
Tim Peters1c9ca872001-10-04 06:43:12 +00001197- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
1198 always returned None, even when there was a class docstring).
1199
1200- doctest now finds and runs docstrings attached to new-style classes,
1201 class methods, static methods, and properties.
1202
Guido van Rossum9074ef62001-10-16 21:34:49 +00001203Core and builtins
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001204-----------------
Tim Petersabf925f2001-09-28 21:53:42 +00001205
Guido van Rossuma8bcf802001-10-15 15:53:58 +00001206- A very subtle syntactical pitfall in list comprehensions was fixed.
1207 For example: [a+b for a in 'abc', for b in 'def']. The comma in
1208 this example is a mistake. Previously, this would silently let 'a'
1209 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
1210 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
1211 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
1212 Note that [a for a in <singleton>] is a convoluted way to say
1213 [<singleton>] anyway, so it's not like any expressiveness is lost.
1214
Guido van Rossum9074ef62001-10-16 21:34:49 +00001215- getattr(obj, name, default) now only catches AttributeError, as
1216 documented, rather than returning the default value for all
1217 exceptions (which could mask bugs in a __getattr__ hook, for
1218 example).
1219
Fred Drakecb7a6b52001-10-22 18:41:51 +00001220- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +00001221 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001222 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +00001223 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +00001224
Guido van Rossum1c486092001-10-19 02:05:35 +00001225- unicode(obj) now behaves more like str(obj), accepting arbitrary
1226 objects, and calling a __unicode__ method if it exists.
1227 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +00001228 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +00001229
Barry Warsawf6fb1712001-10-19 05:35:40 +00001230- isinstance() now allows any object as the first argument and a
1231 class, a type or something with a __bases__ tuple attribute for the
1232 second argument. The second argument may also be a tuple of a
1233 class, type, or something with __bases__, in which case isinstance()
1234 will return true if the first argument is an instance of any of the
1235 things contained in the second argument tuple. E.g.
1236
1237 isinstance(x, (A, B))
1238
1239 returns true if x is an instance of A or B.
1240
Guido van Rossum9074ef62001-10-16 21:34:49 +00001241Extension modules
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001242-----------------
Guido van Rossum9074ef62001-10-16 21:34:49 +00001243
1244- thread.start_new_thread() now returns the thread ID (previously None).
1245
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001246- binascii has now two quopri support functions, a2b_qp and b2a_qp.
1247
Guido van Rossumc524d952001-10-19 01:31:59 +00001248- readline now supports setting the startup_hook and the
1249 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +00001250
Guido van Rossumc524d952001-10-19 01:31:59 +00001251- os and posix supports chroot(), setgroups() and unsetenv() where
1252 available. The stat(), fstat(), statvfs() and fstatvfs() functions
1253 now return "pseudo-sequences" -- the various fields can now be
1254 accessed as attributes (e.g. os.stat("/").st_mtime) but for
1255 backwards compatibility they also behave as a fixed-length sequence.
1256 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +00001257 attributes.
1258
1259- time: localtime(), gmtime() and strptime() now return a
1260 pseudo-sequence similar to the os.stat() return value, with
1261 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +00001262
Guido van Rossum9074ef62001-10-16 21:34:49 +00001263- Decompression objects in the zlib module now accept an optional
1264 second parameter to decompress() that specifies the maximum amount
1265 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +00001266
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001267- optional SSL support in the socket module now exports OpenSSL
1268 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
1269 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +00001270 automatically seed its PRNG. Also, the keyfile and certfile
1271 arguments to socket.ssl() are now optional.
1272
1273- posixmodule (and by extension, the os module on POSIX platforms) now
1274 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001275
Guido van Rossum9074ef62001-10-16 21:34:49 +00001276Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001277-------
Guido van Rossum3c288632001-10-16 21:13:49 +00001278
Tim Peters7402f792001-10-02 03:53:41 +00001279- doctest now excludes functions and classes not defined by the module
1280 being tested, thanks to Tim Hochberg.
1281
Fred Drakecb7a6b52001-10-22 18:41:51 +00001282- HotShot, a new profiler implemented using a C-based callback, has
1283 been added. This substantially reduces the overhead of profiling,
1284 but it is still quite preliminary. Support modules and
1285 documentation will be added in upcoming releases (before 2.2 final).
1286
Guido van Rossumc4b09b42001-10-04 10:19:00 +00001287- profile now produces correct output in situations where an exception
1288 raised in Python is cleared by C code (e.g. hasattr()). This used
1289 to cause wrong output, including spurious claims of recursive
1290 functions and attribution of time spent to the wrong function.
1291
Tim Peters0a1fc4e2001-10-07 03:12:08 +00001292 The code and documentation for the derived OldProfile and HotProfile
1293 profiling classes was removed. The code hasn't worked for years (if
1294 you tried to use them, they raised exceptions). OldProfile
1295 intended to reproduce the behavior of the profiler Python used more
1296 than 7 years ago, and isn't interesting anymore. HotProfile intended
1297 to provide a faster profiler (but producing less information), and
1298 that's a worthy goal we intend to meet via a different approach (but
1299 without losing information).
1300
Tim Peterscce092d2001-10-09 05:31:56 +00001301- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +00001302 a much better system-specific calibration constant. The constant can
1303 now be specified in an instance constructor, or as a Profile class or
1304 instance variable, instead of by editing profile.py's source code.
1305 Calibration must still be done manually (see the docs for the profile
1306 module).
1307
1308 Note that Profile.calibrate() must be overriden by subclasses.
1309 Improving the accuracy required exploiting detailed knowledge of
1310 profiler internals; the earlier method abstracted away the details
1311 and measured a simplified model instead, but consequently computed
1312 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +00001313
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001314- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +00001315 which indicates whether output is intended for the header 'Q'
1316 encoding.
1317
Guido van Rossuma5343cc2001-10-18 18:02:07 +00001318- The SocketServer.ThreadingMixIn class now closes the request after
1319 finish_request() returns. (Not when it errors out though.)
1320
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001321- The nntplib module's NNTP.body() method has grown a 'file' argument
Barry Warsawf6fb1712001-10-19 05:35:40 +00001322 to allow saving the message body to a file.
1323
1324- The email package has added a class email.Parser.HeaderParser which
1325 only parses headers and does not recurse into the message's body.
1326 Also, the module/class MIMEAudio has been added for representing
1327 audio data (contributed by Anthony Baxter).
1328
1329- ftplib should be able to handle files > 2GB.
1330
1331- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
1332 ON, and OFF.
1333
Fred Drakecb7a6b52001-10-22 18:41:51 +00001334- xml.dom.minidom NodeList objects now support the length attribute
1335 and item() method as required by the DOM specifications.
1336
Guido van Rossumed554f62001-10-02 23:15:37 +00001337Tools/Demos
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001338-----------
Guido van Rossumed554f62001-10-02 23:15:37 +00001339
1340- Demo/dns was removed. It no longer serves any purpose; a package
1341 derived from it is now maintained by Anthony Baxter, see
1342 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +00001343
Barry Warsawf6fb1712001-10-19 05:35:40 +00001344- The freeze tool has been made more robust, and two new options have
1345 been added: -X and -E.
1346
Tim Petersabf925f2001-09-28 21:53:42 +00001347Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001348-----
Tim Petersabf925f2001-09-28 21:53:42 +00001349
Barry Warsawf6fb1712001-10-19 05:35:40 +00001350- configure will use CXX in LINKCC if CXX is used to build main() and
1351 the system requires to link a C++ main using the C++ compiler.
1352
Tim Petersabf925f2001-09-28 21:53:42 +00001353C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001354-----
Tim Petersabf925f2001-09-28 21:53:42 +00001355
Guido van Rossum6c4bce32001-10-18 19:20:25 +00001356- The documentation for the tp_compare slot is updated to require that
1357 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
1358 not correct. This is not yet enforced but will be enforced in
1359 Python 2.3; even later, we may use -2 to indicate errors and +2 for
1360 "NotImplemented". Right now, -1 should be used for an error return.
1361
Tim Petersd38b1c72001-09-30 05:09:37 +00001362- PyLong_AsLongLong() now accepts int (as well as long) arguments.
1363 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
1364 as long) arguments.
1365
Guido van Rossum3c288632001-10-16 21:13:49 +00001366- PyThread_start_new_thread() now returns a long int giving the thread
1367 ID, if one can be calculated; it returns -1 for error, 0 if no
1368 thread ID is calculated (this is an incompatible change, but only
1369 the thread module used this API). This code has only really been
1370 tested on Linux and Windows; other platforms please beware (and
1371 report any bugs or strange behavior).
1372
Guido van Rossum1c486092001-10-19 02:05:35 +00001373- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
1374 input.
1375
Tim Petersabf925f2001-09-28 21:53:42 +00001376New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001377-------------
Tim Petersabf925f2001-09-28 21:53:42 +00001378
1379Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001380-----
Tim Petersabf925f2001-09-28 21:53:42 +00001381
1382Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001383-------
Tim Petersabf925f2001-09-28 21:53:42 +00001384
Tim Peters04cf1d32001-10-09 22:39:40 +00001385- Installer: If you install IDLE, and don't disable file-extension
1386 registration, a new "Edit with IDLE" context (right-click) menu entry
1387 is created for .py and .pyw files.
1388
Tim Peters1ce3cf72001-10-01 17:58:40 +00001389- The signal module now supports SIGBREAK on Windows, thanks to Steven
1390 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
1391 action remains to call Win32 ExitProcess(). This can be changed via
Skip Montanaroa2a07bc2002-09-30 15:23:01 +00001392 signal.signal(). For example::
Tim Peters1ce3cf72001-10-01 17:58:40 +00001393
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001394 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
1395 # (SIGINT) behavior.
1396 import signal
1397 signal.signal(signal.SIGBREAK, signal.default_int_handler)
Tim Peters1ce3cf72001-10-01 17:58:40 +00001398
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001399 try:
1400 while 1:
1401 pass
1402 except KeyboardInterrupt:
1403 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
1404 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
1405 # program without the possibility for any Python-level cleanup).
1406 print "Clean exit"
Tim Peters1ce3cf72001-10-01 17:58:40 +00001407
Tim Petersabf925f2001-09-28 21:53:42 +00001408
Tim Petersb07352e2001-09-08 01:25:47 +00001409What's New in Python 2.2a4?
1410===========================
1411
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001412*Release date: 28-Sep-2001*
1413
Guido van Rossum808eea72001-09-25 04:15:41 +00001414Type/class unification and new-style classes
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001415--------------------------------------------
Guido van Rossum808eea72001-09-25 04:15:41 +00001416
1417- pydoc and inspect are now aware of new-style classes;
1418 e.g. help(list) at the interactive prompt now shows proper
1419 documentation for all operations on list objects.
1420
1421- Applications using Jim Fulton's ExtensionClass module can now safely
1422 be used with Python 2.2. In particular, Zope 2.4.1 now works with
1423 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
1424 examples also work again. It is hoped that Gtk and Boost also work
1425 with 2.2a4 and beyond. (If you can confirm this, please write
1426 webmaster@python.org; if there are still problems, please open a bug
1427 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +00001428
Tim Peters66c1a522001-09-24 21:17:50 +00001429- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001430 These map to read-only attributes 'fget', 'fset', 'fdel', and '__doc__'
Tim Peters66c1a522001-09-24 21:17:50 +00001431 in the constructed property object. fget, fset and fdel weren't
1432 discoverable from Python in 2.2a3. __doc__ is new, and allows to
1433 associate a docstring with a property.
1434
Guido van Rossum808eea72001-09-25 04:15:41 +00001435- Comparison overloading is now more completely implemented. For
1436 example, a str subclass instance can properly be compared to a str
1437 instance, and it can properly overload comparison. Ditto for most
1438 other built-in object types.
1439
1440- The repr() of new-style classes has changed; instead of <type
1441 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
1442 *except* for built-in types, which are still rendered as <type
1443 'Foo'> (to avoid upsetting existing code that might parse or
1444 otherwise rely on repr() of certain type objects).
1445
1446- The repr() of new-style objects is now always <Foo object at XXX>;
1447 previously, it was sometimes <Foo instance at XXX>.
1448
1449- For new-style classes, what was previously called __getattr__ is now
1450 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001451 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +00001452 one in classic classes is defined which is called only if regular
1453 attribute access raises AttributeError; to catch *all* attribute
1454 access, you can use __getattribute__ (for new-style classes). If
1455 both are defined, __getattribute__ is called first, and if it raises
1456 AttributeError, __getattr__ is called.
1457
1458- The __class__ attribute of new-style objects can be assigned to.
1459 The new class must have the same C-level object layout as the old
1460 class.
1461
1462- The builtin file type can be subclassed now. In the usual pattern,
1463 "file" is the name of the builtin type, and file() is a new builtin
1464 constructor, with the same signature as the builtin open() function.
1465 file() is now the preferred way to open a file.
1466
1467- Previously, __new__ would only see sequential arguments passed to
1468 the type in a constructor call; __init__ would see both sequential
1469 and keyword arguments. This made no sense whatsoever any more, so
1470 now both __new__ and __init__ see all arguments.
1471
1472- Previously, hash() applied to an instance of a subclass of str or
1473 unicode always returned 0. This has been repaired.
1474
1475- Previously, an operation on an instance of a subclass of an
1476 immutable type (int, long, float, complex, tuple, str, unicode),
1477 where the subtype didn't override the operation (and so the
1478 operation was handled by the builtin type), could return that
1479 instance instead a value of the base type. For example, if s was of
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001480 a str subclass type, s[:] returned s as-is. Now it returns a str
Guido van Rossum808eea72001-09-25 04:15:41 +00001481 with the same value as s.
1482
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001483- Provisional support for pickling new-style objects has been added.
1484
Guido van Rossum808eea72001-09-25 04:15:41 +00001485Core
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001486----
Guido van Rossum808eea72001-09-25 04:15:41 +00001487
Tim Peters2c9aa5e2001-09-23 04:06:05 +00001488- file.writelines() now accepts any iterable object producing strings.
1489
Marc-André Lemburgaefd7662001-09-20 12:59:37 +00001490- PyUnicode_FromEncodedObject() now works very much like
1491 PyObject_Str(obj) in that it tries to use __str__/tp_str
1492 on the object if the object is not a string or buffer. This
1493 makes unicode() behave like str() when applied to non-string/buffer
1494 objects.
1495
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001496- PyFile_WriteObject now passes Unicode objects to the file's write
1497 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +00001498 of a print statement must support Unicode objects, i.e. they must
1499 at least convert them into ASCII strings.
1500
Guido van Rossum624c8af2001-09-18 15:21:04 +00001501- Thread scheduling on Solaris should be improved; it is no longer
1502 necessary to insert a small sleep at the start of a thread in order
1503 to let other runnable threads be scheduled.
1504
Tim Petersb07352e2001-09-08 01:25:47 +00001505Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001506-------
Tim Petersb07352e2001-09-08 01:25:47 +00001507
Marc-André Lemburgbf990172001-09-27 14:17:33 +00001508- StringIO.StringIO instances and cStringIO.StringIO instances support
1509 read character buffer compatible objects for their .write() methods.
1510 These objects are converted to strings and then handled as such
1511 by the instances.
1512
Barry Warsaw2f600732001-09-24 04:28:10 +00001513- The "email" package has been added. This is basically a port of the
1514 mimelib package <http://sf.net/projects/mimelib> with API changes
1515 and some implementations updated to use iterators and generators.
1516
Tim Peters8a9c2842001-09-22 21:30:22 +00001517- difflib.ndiff() and difflib.Differ.compare() are generators now. This
1518 restores the ability of Tools/scripts/ndiff.py to start producing output
1519 before the entire comparison is complete.
1520
Barry Warsaw58b072d2001-09-22 04:44:21 +00001521- StringIO.StringIO instances and cStringIO.StringIO instances support
1522 iteration just like file objects (i.e. their .readline() method is
1523 called for each iteration until it returns an empty string).
1524
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +00001525- The codecs module has grown four new helper APIs to access
1526 builtin codecs: getencoder(), getdecoder(), getreader(),
1527 getwriter().
1528
Guido van Rossum624c8af2001-09-18 15:21:04 +00001529- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
1530 simplifies writing XML RPC servers.
1531
Barry Warsaw647d5e82001-09-28 17:01:02 +00001532- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +00001533 after interpretation of symbolic links. On non-Unix systems, this
1534 is an alias for os.path.abspath().
1535
Tim Peters16a77ad2001-09-08 04:00:12 +00001536- operator.indexOf() (PySequence_Index() in the C API) now works with any
1537 iterable object.
1538
Guido van Rossum624c8af2001-09-18 15:21:04 +00001539- smtplib now supports various authentication and security features of
1540 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001541
Guido van Rossum624c8af2001-09-18 15:21:04 +00001542- hmac: a new module implementing keyed hashing for message
1543 authentication.
1544
1545- mimetypes now recognizes more extensions and file types. At the
1546 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001547
Guido van Rossum624c8af2001-09-18 15:21:04 +00001548- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001549 Python 2.2 bytecode generation. It has also been promoted from a
1550 Tool to a standard library package. (Tools/compiler still exists as
1551 a sample driver.)
1552
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001553Tools
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001554-----
Guido van Rossum624c8af2001-09-18 15:21:04 +00001555
Tim Petersb07352e2001-09-08 01:25:47 +00001556Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001557-----
Tim Petersb07352e2001-09-08 01:25:47 +00001558
Guido van Rossum624c8af2001-09-18 15:21:04 +00001559- Large file support (LFS) is now automatic when the platform supports
1560 it; no more manual configuration tweaks are needed. On Linux, at
1561 least, it's possible to have a system whose C library supports large
1562 files but whose kernel doesn't; in this case, large file support is
1563 still enabled but doesn't do you any good unless you upgrade your
1564 kernel or share your Python executable with another system whose
1565 kernel has large file support.
1566
1567- The configure script now supplies plausible defaults in a
1568 cross-compilation environment. This doesn't mean that the supplied
1569 values are always correct, or that cross-compilation now works
1570 flawlessly -- but it's a first step (and it shuts up most of
1571 autoconf's warnings about AC_TRY_RUN).
1572
1573- The Unix build is now a bit less chatty, courtesy of the parser
1574 generator. The build is completely silent (except for errors) when
1575 using "make -s", thanks to a -q option to setup.py.
1576
Tim Petersb07352e2001-09-08 01:25:47 +00001577C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001578-----
Tim Petersb07352e2001-09-08 01:25:47 +00001579
Guido van Rossum624c8af2001-09-18 15:21:04 +00001580- The "structmember" API now supports some new flag bits to deny read
1581 and/or write access to attributes in restricted execution mode.
1582
Tim Petersb07352e2001-09-08 01:25:47 +00001583New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001584-------------
Tim Petersb07352e2001-09-08 01:25:47 +00001585
Guido van Rossum624c8af2001-09-18 15:21:04 +00001586- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1587 (http://familiar.handhelds.org).
1588
Tim Petersb07352e2001-09-08 01:25:47 +00001589Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001590-----
Tim Petersb07352e2001-09-08 01:25:47 +00001591
Tim Peters8a9c2842001-09-22 21:30:22 +00001592- The "classic" standard tests, which work by comparing stdout to
1593 an expected-output file under Lib/test/output/, no longer stop at
1594 the first mismatch. Instead the test is run to completion, and a
1595 variant of ndiff-style comparison is used to report all differences.
1596 This is much easier to understand than the previous style of reporting.
1597
1598- The unittest-based standard tests now use regrtest's test_main()
1599 convention, instead of running as a side-effect of merely being
1600 imported. This allows these tests to be run in more natural and
1601 flexible ways as unittests, outside the regrtest framework.
1602
1603- regrtest.py is much better integrated with unittest and doctest now,
1604 especially in regard to reporting errors.
1605
Tim Petersb07352e2001-09-08 01:25:47 +00001606Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001607-------
Tim Petersb07352e2001-09-08 01:25:47 +00001608
Guido van Rossum624c8af2001-09-18 15:21:04 +00001609- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001610 that support it (NTFS under Windows 2000). See "What's New in
1611 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001612
Tim Petersb07352e2001-09-08 01:25:47 +00001613
Tim Petersedc99312001-08-22 21:36:50 +00001614What's New in Python 2.2a3?
1615===========================
1616
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001617*Release Date: 07-Sep-2001*
1618
Tim Petersedc99312001-08-22 21:36:50 +00001619Core
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001620----
Tim Petersedc99312001-08-22 21:36:50 +00001621
Tim Peters9fffa3e2001-09-04 05:14:19 +00001622- Conversion of long to float now raises OverflowError if the long is too
1623 big to represent as a C double.
1624
Tim Peters32f453e2001-09-03 08:35:41 +00001625- The 3-argument builtin pow() no longer allows a third non-None argument
1626 if either of the first two arguments is a float, or if both are of
1627 integer types and the second argument is negative (in which latter case
1628 the arguments are converted to float, so this is really the same
1629 restriction).
1630
Tim Peters5d2b77c2001-09-03 05:47:38 +00001631- The builtin dir() now returns more information, and sometimes much
1632 more, generally naming all attributes of an object, and all attributes
1633 reachable from the object via its class, and from its class's base
1634 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1635 an empty list. In 2.2a3,
1636
1637 >>> dir([])
1638 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1639 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1640 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1641 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1642 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1643 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1644 'reverse', 'sort']
1645
1646 dir(module) continues to return only the module's attributes, though.
1647
Tim Petersbdee63f2001-09-02 03:40:59 +00001648- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001649 than raising OverflowError. This is a partial implementation of PEP
1650 237. You can use -Wdefault::OverflowWarning to enable a warning for
1651 this situation, and -Werror::OverflowWarning to revert to the old
1652 OverflowError exception.
1653
Guido van Rossum61c345f2001-09-04 03:26:15 +00001654- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001655 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001656 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1657 -Qold, meaning the / operator has its classic meaning and no
1658 warnings are issued. Using -Qwarn issues a run-time warning about
1659 all uses of classic division for int and long arguments; -Qwarnall
1660 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001661 (for use with fixdiv.py).
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001662 [Note: the remainder of this item (preserved below) became
1663 obsolete in 2.2c1 -- -Qnew has global effect in 2.2] ::
1664
1665 Using -Qnew is questionable; it turns on new division by default, but
1666 only in the __main__ module. You can usefully combine -Qwarn or
1667 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1668 warns about classic division everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +00001669
Tim Petersbdee63f2001-09-02 03:40:59 +00001670- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001671 long, float, str, unicode, and tuple. (The types complex, list and
1672 dictionary can also be subclassed; this was introduced earlier.)
1673 Note that restrictions apply when subclassing immutable built-in
1674 types: you can only affect the value of the instance by overloading
1675 __new__. You can add mutable attributes, and the subclass instances
1676 will have a __dict__ attribute, but you cannot change the "value"
1677 (as implemented by the base class) of an immutable subclass instance
1678 once it is created.
1679
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001680- The dictionary constructor now takes an optional argument, a
1681 mapping-like object, and initializes the dictionary from its
1682 (key, value) pairs.
1683
Tim Petersbdee63f2001-09-02 03:40:59 +00001684- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001685 "cooperative super calls" in a multiple inheritance setting. For an
1686 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1687
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001688- A new built-in type, property, has been added. This enables the
1689 creation of "properties". These are attributes implemented by
1690 getter and setter functions (or only one of these for read-only or
1691 write-only attributes), without the need to override __getattr__.
1692 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001693
Tim Petersbdee63f2001-09-02 03:40:59 +00001694- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001695 liberalized, to allow leading zeroes. Examples of literals now
1696 legal that were SyntaxErrors before:
1697
1698 00.0 0e3 0100j 07.5 00000000000000000008.
1699
Tim Petersbdee63f2001-09-02 03:40:59 +00001700- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001701 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1702
Tim Petersedc99312001-08-22 21:36:50 +00001703Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001704-------
Tim Petersedc99312001-08-22 21:36:50 +00001705
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001706- telnetlib includes symbolic names for the options, and support for
1707 setting an option negotiation callback.
1708
Tim Petersa40c7932001-09-05 22:36:56 +00001709- The new C standard no longer requires that math libraries set errno to
1710 ERANGE on overflow. For platform libraries that exploit this new
1711 freedom, Python's overflow-checking was wholly broken. A new overflow-
1712 checking scheme attempts to repair that, but may not be reliable on all
1713 platforms (C doesn't seem to provide anything both useful and portable
1714 in this area anymore).
1715
Martin v. Löwis44f86962001-09-05 13:44:54 +00001716- Asynchronous timeout actions are available through the new class
1717 threading.Timer.
1718
Tim Peters78526162001-09-05 00:53:45 +00001719- math.log and math.log10 now return sensible results for even huge
1720 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1721
Tim Petersbdee63f2001-09-02 03:40:59 +00001722- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001723 currently held. See the docs for the imp module.
1724
Tim Petersbdee63f2001-09-02 03:40:59 +00001725- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001726 dumps containing ints written on platforms where Python ints are 8 bytes.
1727 When read on a box where Python ints are 4 bytes, such values are
1728 converted to Python longs.
1729
Tim Petersbdee63f2001-09-02 03:40:59 +00001730- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001731 code objects is no longer allowed. This plugs a security hole.
1732
Steve Purcell6091cd62001-09-06 16:05:17 +00001733- unittest.TestResult instances no longer store references to tracebacks
1734 generated by test failures. This prevents unexpected dangling references
1735 to objects that should be garbage collected between tests.
1736
Tim Petersedc99312001-08-22 21:36:50 +00001737Tools
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001738-----
Tim Petersedc99312001-08-22 21:36:50 +00001739
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001740- Tools/scripts/fixdiv.py has been added which can be used to fix
1741 division operators as per PEP 238.
1742
Tim Petersedc99312001-08-22 21:36:50 +00001743Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001744-----
Tim Petersedc99312001-08-22 21:36:50 +00001745
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001746- If you are an adventurous person using Mac OS X you may want to look at
1747 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1748 application, which can be used for experimenting with Carbon or Cocoa.
1749 Discussion of this on pythonmac-sig, please.
1750
Tim Peters7eea37e2001-09-04 22:08:56 +00001751C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001752-----
Tim Peters7eea37e2001-09-04 22:08:56 +00001753
1754- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001755
Tim Peters9fffa3e2001-09-04 05:14:19 +00001756- Note that PyLong_AsDouble can fail! This has always been true, but no
1757 callers checked for it. It's more likely to fail now, because overflow
Skip Montanaroa2a07bc2002-09-30 15:23:01 +00001758 errors are properly detected now. The proper way to check::
Tim Peters9fffa3e2001-09-04 05:14:19 +00001759
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001760 double x = PyLong_AsDouble(some_long_object);
1761 if (x == -1.0 && PyErr_Occurred()) {
1762 /* The conversion failed. */
1763 }
Tim Peters9fffa3e2001-09-04 05:14:19 +00001764
Tim Petersbdee63f2001-09-02 03:40:59 +00001765- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001766 compile but will not participate in GC. To upgrade an extension
1767 module:
1768
1769 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001770
Neil Schemenauer4042c692001-08-30 15:38:01 +00001771 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1772 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001773
Neil Schemenauer4042c692001-08-30 15:38:01 +00001774 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1775 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001776
Neil Schemenauer4042c692001-08-30 15:38:01 +00001777 - remove PyGC_HEAD_SIZE from object size calculations
1778
1779 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1780
Tim Petersbdee63f2001-09-02 03:40:59 +00001781- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001782 These can be used safely to construct string objects from a
1783 sprintf-style format string (similar to the format string supported
1784 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001785
Tim Petersedc99312001-08-22 21:36:50 +00001786New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001787-------------
Tim Petersedc99312001-08-22 21:36:50 +00001788
Tim Petersb7da0902001-09-02 23:01:43 +00001789- Stephen Hansen contributed patches sufficient to get a clean compile
1790 under Borland C (Windows), but he reports problems running it and ran
1791 out of time to complete the port. Volunteers? Expect a MemoryError
1792 when importing the types module; this is probably shallow, and
1793 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001794
Tim Petersedc99312001-08-22 21:36:50 +00001795Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001796-----
Tim Petersedc99312001-08-22 21:36:50 +00001797
1798Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001799-------
Tim Petersedc99312001-08-22 21:36:50 +00001800
Tim Peters6e13a562001-09-06 00:32:15 +00001801- Large file support is now enabled on Win32 platforms as well as on
1802 Win64. This means that, for example, you can use f.tell() and f.seek()
1803 to manipulate files larger than 2 gigabytes (provided you have enough
1804 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001805 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1806 filesize limit, and large file support makes no difference there.
1807 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1808 NTFS has no practical limit on file size, and files of any size can be
1809 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001810
Tim Petersbdee63f2001-09-02 03:40:59 +00001811- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001812 points to command.com (patch from Brian Quinlan).
1813
Tim Petersedc99312001-08-22 21:36:50 +00001814
Tim Peters20f51a72001-07-21 02:31:40 +00001815What's New in Python 2.2a2?
1816===========================
1817
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001818*Release Date: 22-Aug-2001*
1819
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001820Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001821-----
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001822
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001823- Tim Peters developed a brand new Windows installer using Wise 8.1,
1824 generously donated to us by Wise Solutions.
1825
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001826- configure supports a new option --enable-unicode, with the values
1827 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1828 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001829
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001830- A new configure option --enable-framework builds a Mac OS X framework,
1831 which "make frameworkinstall" will install. This provides a starting
1832 point for more mac-like functionality, join pythonmac-sig@python.org
1833 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001834
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001835- The NeXT platform is no longer supported.
1836
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001837- The 'new' module is now statically linked.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001838
Tim Peters0afb6092001-08-15 06:06:44 +00001839Tools
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001840-----
Tim Peters0afb6092001-08-15 06:06:44 +00001841
1842- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001843 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001844 the module docstring for details.
1845
Tim Peters20f51a72001-07-21 02:31:40 +00001846Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001847-----
Tim Peters20f51a72001-07-21 02:31:40 +00001848
Tim Peters5e824c32001-08-12 22:25:01 +00001849- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001850 platforms, allowing to give clearer test result output. regrtest
1851 also has optional --use/-u switch to run normally disabled tests
1852 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001853
Tim Peters20f51a72001-07-21 02:31:40 +00001854- Several new tests in the standard test suite, with special thanks to
1855 Nick Mathewson.
1856
1857Core
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001858----
Tim Peters20f51a72001-07-21 02:31:40 +00001859
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001860- The floor division operator // has been added as outlined in PEP
1861 238. The / operator still provides classic division (and will until
1862 Python 3.0) unless "from __future__ import division" is included, in
1863 which case the / operator will provide true division. The operator
1864 module provides truediv() and floordiv() functions. Augmented
1865 assignment variants are included, as are the equivalent overloadable
1866 methods and C API methods. See the PEP for a full discussion:
1867 <http://python.sf.net/peps/pep-0238.html>
1868
Tim Peters6cd6a822001-08-17 22:11:27 +00001869- Future statements are now effective in simulated interactive shells
1870 (like IDLE). This should "just work" by magic, but read Michael
1871 Hudson's "Future statements in simulated shells" PEP 264 for full
1872 details: <http://python.sf.net/peps/pep-0264.html>.
1873
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001874- The type/class unification (PEP 252-253) was integrated into the
1875 trunk and is not so tentative any more (the exact specification of
1876 some features is still tentative). A lot of work has done on fixing
1877 bugs and adding robustness and features (performance still has to
1878 come a long way).
1879
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001880- Warnings about a mismatch in the Python API during extension import
1881 now use the Python warning framework (which makes it possible to
1882 write filters for these warnings).
1883
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001884- A function's __dict__ (aka func_dict) will now always be a
1885 dictionary. It used to be possible to delete it or set it to None,
1886 but now both actions raise TypeErrors. It is still legal to set it
1887 to a dictionary object. Getting func.__dict__ before any attributes
1888 have been assigned now returns an empty dictionary instead of None.
1889
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001890- A new command line option, -E, was added which disables the use of
1891 all environment variables, or at least those that are specifically
1892 significant to Python. Usually those have a name starting with
1893 "PYTHON". This was used to fix a problem where the tests fail if
1894 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1895 older distribution.
1896
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001897Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001898-------
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001899
Tim Peters5e824c32001-08-12 22:25:01 +00001900- New class Differ and new functions ndiff() and restore() in difflib.py.
1901 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001902 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001903
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001904- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1905 value using the minimal quoting required for the value; more
1906 reliable than using xml.sax.saxutils.escape() for attribute values.
1907
1908- Readline completion support for cmd.Cmd was added.
1909
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001910- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1911
1912- Added function threading.BoundedSemaphore()
1913
1914- Added Ka-Ping Yee's cgitb.py module.
1915
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001916- The 'new' module now exposes the CO_xxx flags.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001917
Martin v. Löwis560da622001-11-24 09:24:51 +00001918- The gc module offers the get_referents function.
1919
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001920New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001921-------------
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001922
1923C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001924-----
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001925
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001926- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1927 which provide a cross-platform implementations for the
1928 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1929 the standard sprintf() and vsprintf() C lib APIs, these versions
1930 apply bounds checking on the used buffer which enhances protection
1931 against buffer overruns.
1932
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001933- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001934 and extensions using different Unicode widths is rendered next to
1935 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001936 will result in an ImportError. Unicode extensions writers must make
1937 sure to check the Unicode width compatibility in their extensions by
1938 using at least one of the mangled Unicode APIs in the extension.
1939
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001940- Two new flags METH_NOARGS and METH_O are available in method definition
1941 tables to simplify implementation of methods with no arguments and a
1942 single untyped argument. Calling such methods is more efficient than
1943 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1944 deprecated.
1945
Tim Petersc1731372001-08-04 08:12:36 +00001946Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001947-------
Tim Petersc1731372001-08-04 08:12:36 +00001948
1949- "import module" now compiles module.pyw if it exists and nothing else
1950 relevant is found.
1951
Tim Peters20f51a72001-07-21 02:31:40 +00001952
Guido van Rossum55a78992001-07-17 17:22:32 +00001953What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +00001954===========================
1955
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001956*Release date: 18-Jul-2001*
1957
Tim Petersf553f892001-05-01 20:45:31 +00001958Core
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001959----
Tim Petersa814db52001-05-14 07:05:58 +00001960
Tim Peters6d6c1a32001-08-02 04:15:00 +00001961- TENTATIVELY, a large amount of code implementing much of what's
1962 described in PEP 252 (Making Types Look More Like Classes) and PEP
1963 253 (Subtyping Built-in Types) was added. This will be released
1964 with Python 2.2a1. Documentation will be provided separately
1965 through http://www.python.org/2.2/. The purpose of releasing this
1966 with Python 2.2a1 is to test backwards compatibility. It is
1967 possible, though not likely, that a decision is made not to release
1968 this code as part of 2.2 final, if any serious backwards
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00001969 incompatibilities are found during alpha testing that cannot be
Tim Peters6d6c1a32001-08-02 04:15:00 +00001970 repaired.
1971
Guido van Rossum55a78992001-07-17 17:22:32 +00001972- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001973 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001974 more 'yield' statements. See PEP 255. Since this adds a new
1975 keyword to the language, this feature must be enabled by including a
1976 future statement: "from __future__ import generators" (see PEP 236).
1977 Generators will become a standard feature in a future release
1978 (probably 2.3). Without this future statement, 'yield' remains an
1979 ordinary identifier, but a warning is issued each time it is used.
1980 (These warnings currently don't conform to the warnings framework of
1981 PEP 230; we intend to fix this in 2.2a2.)
1982
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001983- The UTF-16 codec was modified to be more RFC compliant. It will now
1984 only remove BOM characters at the start of the string and then
1985 only if running in native mode (UTF-16-LE and -BE won't remove a
1986 leading BMO character).
1987
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001988- Strings now have a new method .decode() to complement the already
1989 existing .encode() method. These two methods provide direct access
1990 to the corresponding decoders and encoders of the registered codecs.
1991
1992 To enhance the usability of the .encode() method, the special
1993 casing of Unicode object return values was dropped (Unicode objects
1994 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001995
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001996 Both methods will now return whatever the codec in charge of the
1997 requested encoding returns as object, e.g. Unicode codecs will
1998 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1999 will return u"äöü"). This enables codec writer to create codecs
2000 for various simple to use conversions.
2001
2002 New codecs were added to demonstrate these new features (the .encode()
2003 and .decode() columns indicate the type of the returned objects):
2004
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002005 +---------+-----------+-----------+-----------------------------+
2006 |Name | .encode() | .decode() | Description |
2007 +=========+===========+===========+=============================+
2008 |uu | string | string | UU codec (e.g. for email) |
2009 +---------+-----------+-----------+-----------------------------+
2010 |base64 | string | string | base64 codec |
2011 +---------+-----------+-----------+-----------------------------+
2012 |quopri | string | string | quoted-printable codec |
2013 +---------+-----------+-----------+-----------------------------+
2014 |zlib | string | string | zlib compression |
2015 +---------+-----------+-----------+-----------------------------+
2016 |hex | string | string | 2-byte hex codec |
2017 +---------+-----------+-----------+-----------------------------+
2018 |rot-13 | string | Unicode | ROT-13 Unicode charmap codec|
2019 +---------+-----------+-----------+-----------------------------+
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00002020
Mark Hammond2a0af792001-05-14 03:09:36 +00002021- Some operating systems now support the concept of a default Unicode
2022 encoding for file system operations. Notably, Windows supports 'mbcs'
2023 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00002024 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00002025 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00002026
2027 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00002028 functions that return filenames (such as os.listdir()) to return Python
2029 string objects pre-encoded using the default file system encoding for
2030 the platform. As this encoding is likely to be different from Python's
2031 default encoding, converting this name to a Unicode object before passing
2032 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00002033 would attempt to use its default encoding (generally ASCII) rather than
2034 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00002035
Tim Petersa814db52001-05-14 07:05:58 +00002036 In general, this change simply removes surprises when working with
2037 Unicode and the file system, making these operations work as you expect,
2038 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00002039 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00002040
Tim Peters61dff2b2001-05-08 15:43:37 +00002041- Float (and complex) literals in source code were evaluated to full
2042 precision only when running from a .py file; the same code loaded from a
2043 .pyc (or .pyo) file could suffer numeric differences starting at about the
2044 12th significant decimal digit. For example, on a machine with IEEE-754
2045 floating arithmetic,
2046
2047 x = 9007199254740992.0
2048 print long(x)
2049
2050 printed 9007199254740992 if run directly from .py, but 9007199254740000
2051 if from a compiled (.pyc or .pyo) file. This was due to marshal using
2052 str(float) instead of repr(float) when building code objects. marshal
2053 now uses repr(float) instead, which should reproduce floats to full
2054 machine precision (assuming the platform C float<->string I/O conversion
2055 functions are of good quality).
2056
2057 This may cause floating-point results to change in some cases, and
2058 usually for the better, but may also cause numerically unstable
2059 algorithms to break.
2060
Tim Peters2f228e72001-05-13 00:19:31 +00002061- The implementation of dicts suffers fewer collisions, which has speed
2062 benefits. However, the order in which dict entries appear in dict.keys(),
2063 dict.values() and dict.items() may differ from previous releases for a
2064 given dict. Nothing is defined about this order, so no program should
2065 rely on it. Nevertheless, it's easy to write test cases that rely on the
2066 order by accident, typically because of printing the str() or repr() of a
2067 dict to an "expected results" file. See Lib/test/test_support.py's new
2068 sortdict(dict) function for a simple way to display a dict in sorted
2069 order.
2070
Tim Peters7a3bfc32001-06-12 01:22:22 +00002071- Many other small changes to dicts were made, resulting in faster
2072 operation along the most common code paths.
2073
Guido van Rossum10315822001-05-01 20:54:30 +00002074- Dictionary objects now support the "in" operator: "x in dict" means
2075 the same as dict.has_key(x).
2076
Barry Warsaw51acc8d2001-06-26 20:12:50 +00002077- The update() method of dictionaries now accepts generic mapping
2078 objects. Specifically the argument object must support the .keys()
2079 and __getitem__() methods. This allows you to say, for example,
2080 {}.update(UserDict())
2081
Guido van Rossum10315822001-05-01 20:54:30 +00002082- Iterators were added; this is a generalized way of providing values
2083 to a for loop. See PEP 234. There's a new built-in function iter()
2084 to return an iterator. There's a new protocol to get the next value
2085 from an iterator using the next() method (in Python) or the
2086 tp_iternext slot (in C). There's a new protocol to get iterators
2087 using the __iter__() method (in Python) or the tp_iter slot (in C).
2088 Iterating (i.e. a for loop) over a dictionary generates its keys.
2089 Iterating over a file generates its lines.
2090
Tim Petersf553f892001-05-01 20:45:31 +00002091- The following functions were generalized to work nicely with iterator
Skip Montanaroa2a07bc2002-09-30 15:23:01 +00002092 arguments::
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002093
Tim Peterse63415e2001-05-08 04:38:29 +00002094 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00002095 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
2096 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00002097 join() method of strings
2098 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00002099 'x in y' and 'x not in y' (PySequence_Contains() in C API)
2100 operator.countOf() (PySequence_Count() in C API)
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002101 right-hand side of assignment statements with multiple targets, such as ::
Tim Petersd6d010b2001-06-21 02:49:55 +00002102 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00002103
Tim Petersd85e1022001-05-11 21:51:48 +00002104- Accessing module attributes is significantly faster (for example,
2105 random.random or os.path or yourPythonModule.yourAttribute).
2106
Tim Peterse63415e2001-05-08 04:38:29 +00002107- Comparing dictionary objects via == and != is faster, and now works even
2108 if the keys and values don't support comparisons other than ==.
2109
Tim Peters95bf9392001-05-10 08:32:44 +00002110- Comparing dictionaries in ways other than == and != is slower: there were
2111 insecurities in the dict comparison implementation that could cause Python
2112 to crash if the element comparison routines for the dict keys and/or
2113 values mutated the dicts. Making the code bulletproof slowed it down.
2114
Tim Peterseb28ef22001-06-02 05:27:19 +00002115- Collisions in dicts are resolved via a new approach, which can help
2116 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00002117 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00002118 faster now. Thanks to Christian Tismer for pointing out the cause and
2119 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00002120
Tim Peters52e155e2001-06-16 05:42:57 +00002121- repr() is much faster for large containers (dict, list, tuple).
2122
2123
Tim Petersa814db52001-05-14 07:05:58 +00002124Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002125-------
Tim Petersa814db52001-05-14 07:05:58 +00002126
Fred Drake960fdf92001-07-20 18:38:26 +00002127- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002128 were added to the string module. These a locale-independent
Fred Drake960fdf92001-07-20 18:38:26 +00002129 constants, unlike letters, lowercase, and uppercase. These are now
2130 use in appropriate locations in the standard library.
2131
Martin v. Löwisf0473d52001-07-18 16:17:16 +00002132- The flags used in dlopen calls can now be configured using
2133 sys.setdlopenflags and queried using sys.getdlopenflags.
2134
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00002135- Fredrik Lundh's xmlrpclib is now a standard library module. This
2136 provides full client-side XML-RPC support. In addition,
2137 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
2138 one asyncore-based). Thanks to Eric Raymond for the documentation.
2139
Guido van Rossum643d3912001-07-05 14:46:25 +00002140- The xrange() object is simplified: it no longer supports slicing,
2141 repetition, comparisons, efficient 'in' checking, the tolist()
2142 method, or the start, stop and step attributes. See PEP 260.
2143
Martin v. Löwisebf94db2001-06-06 06:25:40 +00002144- A new function fnmatch.filter to filter lists of file names was added.
2145
Barry Warsawffd674d2001-05-22 16:00:10 +00002146- calendar.py uses month and day names based on the current locale.
2147
Guido van Rossum2e0a6542001-05-15 02:14:44 +00002148- strop is now *really* obsolete (this was announced before with 1.6),
2149 and issues DeprecationWarning when used (except for the four items
2150 that are still imported into string.py).
2151
Tim Petersa814db52001-05-14 07:05:58 +00002152- Cookie.py now sorts key+value pairs by key in output strings.
2153
2154- pprint.isrecursive(object) didn't correctly identify recursive objects.
2155 Now it does.
2156
Tim Peters95b3f782001-05-14 18:39:41 +00002157- pprint functions now much faster for large containers (tuple, list, dict).
2158
Tim Peters7b9542a2001-06-10 23:40:19 +00002159- New 'q' and 'Q' format codes in the struct module, corresponding to C
2160 types "long long" and "unsigned long long" (on Windows, __int64). In
2161 native mode, these can be used only when the platform C compiler supports
2162 these types (when HAVE_LONG_LONG is #define'd by the Python config
2163 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00002164 In standard mode, 'q' and 'Q' are supported on all platforms, and are
2165 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00002166
Guido van Rossum83213cc2001-06-12 16:48:52 +00002167- The site module installs a new built-in function 'help' that invokes
2168 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
2169 it displays a message reminding the user to use 'help()' or
2170 'help(object)'.
2171
Tim Petersa814db52001-05-14 07:05:58 +00002172Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002173-----
Tim Petersa814db52001-05-14 07:05:58 +00002174
2175- New test_mutants.py runs dict comparisons where the key and value
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002176 comparison operators mutate the dicts randomly during comparison. This
Tim Petersa814db52001-05-14 07:05:58 +00002177 rapidly causes Python to crash under earlier releases (not for the faint
2178 of heart: it can also cause Win9x to freeze or reboot!).
2179
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002180- New test_pprint.py verifies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00002181 pprint.isreadable() return sensible results. Also verifies that simple
2182 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00002183
Tim Peters4324aa32001-05-28 22:30:08 +00002184C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002185-----
Tim Peters4324aa32001-05-28 22:30:08 +00002186
2187- Removed the unused last_is_sticky argument from the internal
2188 _PyTuple_Resize(). If this affects you, you were cheating.
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002189
2190----
2191
2192**(For information about older versions, consult the HISTORY file.)**