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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
Neal Norwitz94a83fd2002-11-02 17:46:24 +0000295- resource.getrlimit() now returns longs instead of ints.
296
Martin v. Löwis080689c2002-10-26 14:42:02 +0000297- readline now dynamically adjusts its input/output stream if
298 sys.stdin/stdout changes.
299
Guido van Rossumba602972002-10-01 18:18:58 +0000300- The _tkinter module (and hence Tkinter) has dropped support for
301 Tcl/Tk 8.0 and 8.1. Only Tcl/Tk versions 8.2, 8.3 and 8.4 are
302 supported.
303
Martin v. Löwis658009a2002-09-16 17:26:24 +0000304- cPickle.BadPickleGet is now a class.
305
Martin v. Löwisa19bfe02002-10-16 18:28:36 +0000306- The time stamps in os.stat_result are floating point numbers
307 after stat_float_times has been called.
Martin v. Löwis94717ed2002-09-09 14:24:16 +0000308
Neal Norwitzb5673922002-09-05 21:48:07 +0000309- If the size passed to mmap.mmap() is larger than the length of the
310 file on non-Windows platforms, a ValueError is raised. [SF bug 585792]
311
Guido van Rossumb57089c2002-08-06 16:20:26 +0000312- The xreadlines module is slated for obsolescence.
313
Guido van Rossum79f0a102002-07-23 03:32:08 +0000314- The strptime function in the time module is now always available (a
315 Python implementation is used when the C library doesn't define it).
316
Guido van Rossum9562bcf2002-06-14 21:31:18 +0000317- The 'new' module is no longer an extension, but a Python module that
318 only exists for backwards compatibility. Its contents are no longer
319 functions but callable type objects.
320
Tim Peters81b92512002-04-29 01:37:32 +0000321- The bsddb.*open functions can now take 'None' as a filename.
Anthony Baxter83888952002-04-23 02:11:05 +0000322 This will create a temporary in-memory bsddb that won't be
Tim Peters81b92512002-04-29 01:37:32 +0000323 written to disk.
Anthony Baxter83888952002-04-23 02:11:05 +0000324
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000325- posix.lchown, posix.killpg, posix.mknod, and posix.getpgid have been
326 added where available.
Martin v. Löwis06a83e92002-04-14 10:19:44 +0000327
Martin v. Löwisf0a46682002-11-03 17:20:12 +0000328- The locale module now exposes the C library's gettext interface. It
329 also has a new function getpreferredencoding.
Martin v. Löwis2e64c342002-03-27 18:49:02 +0000330
Tim Petersfbf74f22002-03-14 19:06:01 +0000331- A security hole ("double free") was found in zlib-1.1.3, a popular
332 third party compression library used by some Python modules. The
333 hole was quickly plugged in zlib-1.1.4, and the Windows build of
334 Python now ships with zlib-1.1.4.
335
Martin v. Löwis688357e2002-04-08 21:28:20 +0000336- pwd, grp, and resource return enhanced tuples now, with symbolic
337 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +0000338
Martin v. Löwis99866332002-03-01 10:27:01 +0000339- array.array is now a type object. A new format character
340 'u' indicates Py_UNICODE arrays. For those, .tounicode and
341 .fromunicode methods are available. Arrays now support __iadd__
342 and __imul__.
343
Neal Norwitze790eae2002-01-01 21:14:12 +0000344- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +0000345 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
346 is called.
347
Michael W. Hudson34f20ea2002-05-27 15:08:24 +0000348- signal.sigpending, signal.sigprocmask and signal.sigsuspend have
349 been added where available.
350
Skip Montanaro8e790e72002-09-03 13:25:17 +0000351- The sys module acquired a new attribute, api_version, which evaluates
352 to the value of the PYTHON_API_VERSION macro with which the
353 interpreter was compiled.
354
Tim Petersaf8446f2001-12-21 21:36:50 +0000355Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000356-------
Tim Petersaf8446f2001-12-21 21:36:50 +0000357
Tim Petersfb0ea522002-11-04 19:50:11 +0000358- gzip.py now handles files exceeding 2GB. Note that 4GB is still a
359 fundamental limitation of the underlying gzip file format (it only
360 has 32 bits to record the file size).
361
Martin v. Löwis74b51ac2002-10-26 14:50:45 +0000362- xml.sax.saxutils.unescape has been added, to replace entity references
363 with their entity value.
364
Martin v. Löwis77ac4292002-10-15 15:11:13 +0000365- Queue.Queue.{put,get} now support an optional timeout argument.
366
Martin v. Löwisb24e3472002-10-13 10:28:04 +0000367- Various features of Tk 8.4 are exposed in Tkinter.py. The multiple
368 option of tkFileDialog is exposed as function askopenfile{,name}s.
Martin v. Löwis2ec36272002-10-13 10:22:08 +0000369
Martin v. Löwisb24e3472002-10-13 10:28:04 +0000370- Various configure methods of Tkinter have been stream-lined, so that
371 tag_configure, image_configure, window_configure now return a
Tim Petersfb0ea522002-11-04 19:50:11 +0000372 dictionary when invoked with no argument.
Martin v. Löwis6ce13152002-10-10 14:36:13 +0000373
Guido van Rossum2b492b62002-10-09 21:40:48 +0000374- Importing the readline module now no longer has the side effect of
375 calling setlocale(LC_CTYPE, ""). The initial "C" locale, or
376 whatever locale is explicitly set by the user, is preserved. If you
377 want repr() of 8-bit strings in your preferred encoding to preserve
378 all printable characters of that encoding, you have to add the
379 following code to your $PYTHONSTARTUP file or to your application's
380 main():
381
382 import locale
383 locale.setlocale(locale.LC_CTYPE, "")
384
Martin v. Löwise9ce0b02002-10-07 13:23:24 +0000385- shutil.move was added. shutil.copytree now reports errors as an
386 exception at the end, instead of printing error messages.
387
Marc-André Lemburg97047e22002-10-04 11:55:21 +0000388- Encoding name normalization was generalized to not only
389 replace hyphens with underscores, but also all other non-alphanumeric
390 characters (with the exception of the dot which is used for Python
391 package names during lookup). The aliases.py mapping was updated
392 to the new standard.
393
Walter Dörwald5ccaf8f2002-09-06 16:15:58 +0000394- mimetypes has two new functions: guess_all_extensions() which
395 returns a list of all known extensions for a mime type, and
396 add_type() which adds one mapping between a mime type and
397 an extension to the database.
398
Guido van Rossumd8ab35c2002-08-19 16:25:46 +0000399- New module: sets, defines the class Set that implements a mutable
400 set type using the keys of a dict to represent the set. There's
401 also a class ImmutableSet which is useful when you need sets of sets
402 or when you need to use sets as dict keys, and a class BaseSet which
403 is the base class of the two. (This is not documented yet, but
404 help(sets) gives a wealth of information.)
405
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +0000406- Added operator.pow(a,b) which is equivalent to a**b.
407
Tim Peters012c0a32002-08-16 03:40:07 +0000408- random.randrange(-sys.maxint-1, sys.maxint) no longer raises
409 OverflowError. That is, it now accepts any combination of 'start'
410 and 'stop' arguments so long as each is in the range of Python's
411 bounded integers.
412
Guido van Rossum4a57c332002-08-02 18:05:20 +0000413- New "algorithms" module: heapq, implements a heap queue. Thanks to
414 Kevin O'Connor for the code and François Pinard for an entertaining
415 write-up explaining the theory and practical uses of heaps.
416
Marc-André Lemburg58e2ff22002-07-12 14:40:04 +0000417- New encoding for the Palm OS character set: palmos.
418
Tim Peters943382c2002-07-07 03:59:34 +0000419- binascii.crc32() and the zipfile module had problems on some 64-bit
420 platforms. These have been fixed. On a platform with 8-byte C longs,
421 crc32() now returns a signed-extended 4-byte result, so that its value
422 as a Python int is equal to the value computed a 32-bit platform.
423
Martin v. Löwis7d650ca2002-06-30 15:05:00 +0000424- xml.dom.minidom.toxml and toprettyxml now take an optional encoding
425 argument.
426
Guido van Rossum9f7549b2002-06-10 21:39:42 +0000427- Some fixes in the copy module: when an object is copied through its
428 __reduce__ method, there was no check for a __setstate__ method on
429 the result [SF patch 565085]; deepcopy should treat instances of
430 custom metaclasses the same way it treats instances of type 'type'
431 [SF patch 560794].
432
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000433- Sockets now support timeout mode. After s.settimeout(T), where T is
434 a float expressing seconds, subsequent operations raise an exception
435 if they cannot be completed within T seconds. To disable timeout
Guido van Rossum79f0a102002-07-23 03:32:08 +0000436 mode, use s.settimeout(None). There's also a module function,
437 socket.setdefaulttimeout(T), which sets the default for all sockets
438 created henceforth.
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000439
440- getopt.gnu_getopt was added. This supports GNU-style option
441 processing, where options can be mixed with non-option arguments.
Martin v. Löwis446a25f2002-06-06 10:58:36 +0000442
Michael W. Hudsonb0dc1a32002-06-04 18:27:35 +0000443- Stop using strings for exceptions. String objects used for
444 exceptions are now classes deriving from Exception. The objects
445 changed were: Tkinter.TclError, bdb.BdbQuit, macpath.norm_error,
446 tabnanny.NannyNag, and xdrlib.Error.
Neal Norwitzb5b5a262002-06-04 17:14:07 +0000447
Walter Dörwald474458d2002-06-04 15:16:29 +0000448- Constants BOM_UTF8, BOM_UTF16, BOM_UTF16_LE, BOM_UTF16_BE,
449 BOM_UTF32, BOM_UTF32_LE and BOM_UTF32_BE that represent the Byte
450 Order Mark in UTF-8, UTF-16 and UTF-32 encodings for little and
451 big endian systems were added to the codecs module. The old names
452 BOM32_* and BOM64_* were off by a factor of 2.
453
Guido van Rossumf9257822002-06-18 20:43:18 +0000454- Added conversion functions math.degrees() and math.radians().
Raymond Hettinger87f59ee2002-05-13 04:17:32 +0000455
Raymond Hettinger9b1df1d2002-05-12 06:07:21 +0000456- ftplib.retrlines() now tests for callback is None rather than testing
457 for False. Was causing an error when given a callback object which
458 was callable but also returned len() as zero. The change may
459 create new breakage if the caller relied on the undocumented behavior
460 and called with callback set to [] or some other False value not
461 identical to None.
462
Tim Peters46c04e12002-05-05 20:40:00 +0000463- random.gauss() uses a piece of hidden state used by nothing else,
464 and the .seed() and .whseed() methods failed to reset it. In other
465 words, setting the seed didn't completely determine the sequence of
466 results produced by random.gauss(). It does now. Programs repeatedly
467 mixing calls to a seed method with calls to gauss() may see different
468 results now.
469
Fred Drake7f781c92002-05-01 20:33:53 +0000470- The pickle.Pickler class grew a clear_memo() method to mimic that
471 provided by cPickle.Pickler.
472
Tim Peters81b92512002-04-29 01:37:32 +0000473- difflib's SequenceMatcher class now does a dynamic analysis of
474 which elements are so frequent as to constitute noise. For
475 comparing files as sequences of lines, this generally works better
476 than the IS_LINE_JUNK function, and function ndiff's linejunk
477 argument defaults to None now as a result. A happy benefit is
478 that SequenceMatcher may run much faster now when applied
479 to large files with many duplicate lines (for example, C program
480 text with lots of repeated "}" and "return NULL;" lines).
481
Guido van Rossum256705b2002-04-23 13:29:43 +0000482- New Text.dump() method in Tkinter module.
483
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000484- New distutils commands for building packagers were added to
485 support pkgtool on Solaris and swinstall on HP-UX.
486
487- distutils now has a new abstract binary packager base class
488 command/bdist_packager, which simplifies writing packagers.
489 This will hopefully provide the missing bits to encourage
490 people to submit more packagers, e.g. for Debian, FreeBSD
491 and other systems.
492
Guido van Rossumf9257822002-06-18 20:43:18 +0000493- The UTF-16, -LE and -BE stream readers now raise a
494 NotImplementedError for all calls to .readline(). Previously, they
495 used to just produce garbage or fail with an encoding error --
496 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 +0000497 work well with these.
498
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000499- compileall now supports quiet operation.
500
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000501- The BaseHTTPServer now implements optional HTTP/1.1 persistent
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000502 connections.
503
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000504- socket module: the SSL support was broken out of the main
505 _socket module C helper and placed into a new _ssl helper
506 which now gets imported by socket.py if available and working.
507
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000508- encodings package: added aliases for all supported IANA character
509 sets
510
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000511- ftplib: to safeguard the user's privacy, anonymous login will use
512 "anonymous@" as default password, rather than the real user and host
513 name.
514
Fred Drake36736122002-01-10 13:50:31 +0000515- webbrowser: tightened up the command passed to os.system() so that
516 arbitrary shell code can't be executed because a bogus URL was
517 passed in.
518
Tim Peters11bd9942002-02-01 00:52:29 +0000519- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000520 gettext.find an optional all argument. Translations will now fallback
521 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000522
Martin v. Löwis9668b932002-01-12 11:27:42 +0000523- distutils bdist commands now offer a --skip-build option.
524
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000525- warnings.warn now accepts a Warning instance as first argument.
526
Fred Drakefed7e852002-04-04 19:36:15 +0000527- The xml.sax.expatreader.ExpatParser class will no longer create
528 circular references by using itself as the locator that gets passed
529 to the content handler implementation. [SF bug #535474]
530
Barry Warsaw47f3e2c2002-05-20 00:14:24 +0000531- The email.Parser.Parser class now properly parses strings regardless
532 of their line endings, which can be any of \r, \n, or \r\n (CR, LF,
533 or CRLF). Also, the Header class's constructor default arguments
534 has changed slightly so that an explicit maxlinelen value is always
535 honored.
536
Gustavo Niemeyerf8ca8362002-11-05 16:50:05 +0000537- distutils' build_ext command now links c++ extensions with the c++
538 compiler available in the Makefile or CXX environment variable, if
539 running under *nix.
540
541- New module bz2: provides a comprehensive interface for the bz2 compression
542 library. It implements a complete file interface, one-shot (de)compression
543 functions, and types for sequential (de)compression.
544
Tim Petersaf8446f2001-12-21 21:36:50 +0000545Tools/Demos
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000546-----------
Tim Petersaf8446f2001-12-21 21:36:50 +0000547
Guido van Rossum923e4ef2002-09-17 20:58:59 +0000548- The SGI demos (Demo/sgi) have been removed. Nobody thought they
549 were interesting any more. (The SGI library modules and extensions
550 are still there; it is believed that at least some of these are
551 still used and useful.)
552
Fred Drake40813b12002-08-05 15:24:19 +0000553- IDLE supports the new encoding declarations (PEP 263); it can also
554 deal with legacy 8-bit files if they use the locale's encoding. It
555 allows non-ASCII strings in the interactive shell and executes them
556 in the locale's encoding.
Martin v. Löwis98ce7b72002-08-05 15:11:26 +0000557
Marc-André Lemburg46260092002-04-04 16:17:11 +0000558- freeze.py now produces binaries which can import shared modules,
559 unlike before when this failed due to missing symbol exports in
560 the generated binary.
561
Tim Petersaf8446f2001-12-21 21:36:50 +0000562Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000563-----
Tim Petersaf8446f2001-12-21 21:36:50 +0000564
Guido van Rossum6b3db552002-09-25 15:02:44 +0000565- The fpectl module is not built by default; it's dangerous or useless
566 except in the hands of experts.
567
Tim Petersf47630f2002-08-01 02:34:51 +0000568- The public Python C API will generally be declared using PyAPI_FUNC
Guido van Rossum6b3db552002-09-25 15:02:44 +0000569 and PyAPI_DATA macros, while Python extension module init functions
570 will be declared with PyMODINIT_FUNC. DL_EXPORT/DL_IMPORT macros
571 are deprecated.
Neal Norwitz1389f3e2002-07-22 13:21:10 +0000572
Tim Petersc6a3ff62002-07-08 22:11:52 +0000573- A bug was fixed that could cause COUNT_ALLOCS builds to segfault, or
574 get into infinite loops, when a new-style class got garbage-collected.
575 Unfortunately, to avoid this, the way COUNT_ALLOCS works requires
576 that new-style classes be immortal in COUNT_ALLOCS builds. Note that
577 COUNT_ALLOCS is not enabled by default, in either release or debug
578 builds, and that new-style classes are immortal only in COUNT_ALLOCS
579 builds.
580
Tim Peters943382c2002-07-07 03:59:34 +0000581- Compiling out the cyclic garbage collector is no longer an option.
582 The old symbol WITH_CYCLE_GC is now ignored, and Python.h arranges
583 that it's always defined (for the benefit of any extension modules
584 that may be conditionalizing on it). A bonus is that any extension
585 type participating in cyclic gc can choose to participate in the
586 Py_TRASHCAN mechanism now too; in the absence of cyclic gc, this used
587 to require editing the core to teach the trashcan mechanism about the
588 new type.
589
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000590- According to Annex F of the current C standard,
Tim Peters1de41bf2002-07-03 03:31:20 +0000591
592 The Standard C macro HUGE_VAL and its float and long double analogs,
593 HUGE_VALF and HUGE_VALL, expand to expressions whose values are
594 positive infinities.
595
596 Python only uses the double HUGE_VAL, and only to #define its own symbol
597 Py_HUGE_VAL. Some platforms have incorrect definitions for HUGE_VAL.
598 pyport.h used to try to worm around that, but the workarounds triggered
599 other bugs on other platforms, so we gave up. If your platform defines
600 HUGE_VAL incorrectly, you'll need to #define Py_HUGE_VAL to something
601 that works on your platform. The only instance of this I'm sure about
602 is on an unknown subset of Cray systems, described here:
603
604 http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm
605
606 Presumably 2.3a1 breaks such systems. If anyone uses such a system, help!
607
Martin v. Löwisa3fb4f72002-06-09 13:33:54 +0000608- The configure option --without-doc-strings can be used to remove the
609 doc strings from the builtin functions and modules; this reduces the
610 size of the executable.
611
Guido van Rossumadd88062002-08-15 14:01:14 +0000612- The universal newlines option (PEP 278) is on by default. On Unix
613 it can be disabled by passing --without-universal-newlines to the
614 configure script. On other platforms, remove
615 WITH_UNIVERSAL_NEWLINES from pyconfig.h.
Tim Peters639295f2002-04-21 07:30:30 +0000616
Martin v. Löwis1142de32002-03-29 16:28:31 +0000617- On Unix, a shared libpython2.3.so can be created with --enable-shared.
618
Tim Peters8deda702002-03-30 10:06:07 +0000619- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
620 preprocessor symbols were eliminated. The internal decisions they
621 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000622
Fred Drake7d28b732002-05-02 21:17:00 +0000623- The tools used to build the documentation now work under Cygwin as
624 well as Unix.
625
Skip Montanaro57454e52002-06-14 20:30:31 +0000626- The bsddb and dbm module builds have been changed to try and avoid version
627 skew problems and disable linkage with Berkeley DB 1.85 unless the
628 installer knows what s/he's doing. See the section on building these
629 modules in the README file for details.
630
Tim Petersaf8446f2001-12-21 21:36:50 +0000631C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000632-----
Tim Petersaf8446f2001-12-21 21:36:50 +0000633
Guido van Rossum45ec02a2002-08-19 21:43:18 +0000634- The string object's layout has changed: the pointer member
635 ob_sinterned has been replaced by an int member ob_sstate. On some
636 platforms (e.g. most 64-bit systems) this may change the offset of
637 the ob_sval member, so as a precaution the API_VERSION has been
638 incremented. The apparently unused feature of "indirect interned
639 strings", supported by the ob_sinterned member, is gone. Interned
640 strings are now usually mortal; theres a new API,
641 PyString_InternImmortal() that creates immortal interned strings.
642 (The ob_sstate member can only take three values; however, while
643 making it a char saves a few bytes per string object on average, in
644 it also slowed things down a bit because ob_sval was no longer
645 aligned.)
646
Guido van Rossumfdb86482002-08-14 21:20:32 +0000647- The Py_InitModule*() functions now accept NULL for the 'methods'
648 argument. Modules without global functions are becoming more common
649 now that factories can be types rather than functions.
650
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +0000651- New C API PyUnicode_FromOrdinal() which exposes unichr() at C
652 level.
653
Thomas Heller085358a2002-07-29 14:27:41 +0000654- New functions PyErr_SetExcFromWindowsErr() and
655 PyErr_SetExcFromWindowsErrWithFilename(). Similar to
656 PyErr_SetFromWindowsErrWithFilename() and
657 PyErr_SetFromWindowsErr(), but they allow to specify
658 the exception type to raise. Available on Windows.
659
Tim Peters7c321a82002-07-09 02:57:01 +0000660- Py_FatalError() is now declared as taking a const char* argument. It
661 was previously declared without const. This should not affect working
662 code.
663
Martin v. Löwis01f94bd2002-05-08 08:44:21 +0000664- Added new macro PySequence_ITEM(o, i) that directly calls
665 sq_item without rechecking that o is a sequence and without
666 adjusting for negative indices.
667
Fred Draked0ba6362002-05-02 21:28:26 +0000668- PyRange_New() now raises ValueError if the fourth argument is not 1.
669 This is part of the removal of deprecated features of the xrange
670 object.
671
Guido van Rossum517c7d42002-04-26 02:49:14 +0000672- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
673 coercion if both arguments have the same type but this type has the
674 CHECKTYPES flag set. This is to better support proxies.
675
Skip Montanaroa2a07bc2002-09-30 15:23:01 +0000676- The type of tp_free has been changed from "``void (*)(PyObject *)``" to
677 "``void (*)(void *)``".
Neil Schemenauer9344b142002-04-12 23:00:08 +0000678
679- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
680
Guido van Rossum0986d822002-04-08 01:38:42 +0000681- A type can now inherit its metatype from its base type. Previously,
682 when PyType_Ready() was called, if ob_type was found to be NULL, it
683 was always set to &PyType_Type; now it is set to base->ob_type,
684 where base is tp_base, defaulting to &PyObject_Type.
685
686- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
687
Neil Schemenauerc9abc1d2002-05-08 14:14:41 +0000688- The PyCore_* family of APIs have been removed.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000689
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000690- The "u#" parser marker will now pass through Unicode objects as-is
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000691 without going through the buffer API.
692
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000693- The enumerators of cmp_op have been renamed to use the prefix ``PyCmp_``.
Martin v. Löwis7198a522002-01-01 19:59:11 +0000694
Tim Peters10a3bb52001-12-25 19:07:38 +0000695- An old #define of ANY as void has been removed from pyport.h. This
696 hasn't been used since Python's pre-ANSI days, and the #define has
697 been marked as obsolete since then. SF bug 495548 says it created
698 conflicts with other packages, so keeping it around wasn't harmless.
699
Tim Petersaf8446f2001-12-21 21:36:50 +0000700- Because Python's magic number scheme broke on January 1st, we decided
701 to stop Python development. Thanks for all the fish!
702
Tim Petersfb05db22002-03-11 00:24:00 +0000703- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000704 scheme to a new one. See Python/import.c for details.
705
Tim Petersaf8446f2001-12-21 21:36:50 +0000706New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000707-------------
Tim Petersaf8446f2001-12-21 21:36:50 +0000708
Martin v. Löwisf90ae202002-06-11 06:22:31 +0000709- AtheOS is now supported.
710
Andrew MacIntyre161ad0e2002-08-04 07:25:58 +0000711- the EMX runtime environment on OS/2 is now supported.
712
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000713- GNU/Hurd is now supported.
714
Tim Petersaf8446f2001-12-21 21:36:50 +0000715Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000716-----
717
718Yet to be written.
Tim Petersaf8446f2001-12-21 21:36:50 +0000719
720Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000721-------
Tim Petersaf8446f2001-12-21 21:36:50 +0000722
Tim Peters08e72952002-04-16 20:48:01 +0000723- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
724 of that has been fixed in the installer (disabled Wise's "delete in-
725 use files" uninstall option).
726
Guido van Rossum181e41a2002-04-06 00:23:25 +0000727- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
728
Tim Peters33187922002-04-04 20:02:04 +0000729- The installer now installs Start menu shortcuts under (the local
730 equivalent of) "All Users" when doing an Admin install.
731
Tim Petersfb05db22002-03-11 00:24:00 +0000732- file.truncate([newsize]) now works on Windows for all newsize values.
733 It used to fail if newsize didn't fit in 32 bits, reflecting a
734 limitation of MS _chsize (which is no longer used).
735
Tim Petersab034fa2002-02-01 11:27:43 +0000736- os.waitpid() is now implemented for Windows, and can be used to block
737 until a specified process exits. This is similar to, but not exactly
738 the same as, os.waitpid() on POSIX systems. If you're waiting for
739 a specific process whose pid was obtained from one of the spawn()
740 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000741 See the docs for details. The docs were changed to clarify that
742 spawn functions return, and waitpid requires, a process handle on
743 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000744
Tim Peters11bd9942002-02-01 00:52:29 +0000745- New tempfile.TemporaryFile implementation for Windows: this doesn't
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000746 need a TemporaryFileWrapper wrapper anymore, and should be immune
Tim Peters11bd9942002-02-01 00:52:29 +0000747 to a nasty problem: before 2.3, if you got a temp file on Windows, it
748 got wrapped in an object whose close() method first closed the
749 underlying file, then deleted the file. This usually worked fine.
750 However, the spawn family of functions on Windows create (at a low C
751 level) the same set of open files in the spawned process Q as were
752 open in the spawning process P. If a temp file f was among them, then
753 doing f.close() in P first closed P's C-level file handle on f, but Q's
754 C-level file handle on f remained open, so the attempt in P to delete f
755 blew up with a "Permission denied" error (Windows doesn't allow
756 deleting open files). This was surprising, subtle, and difficult to
757 work around.
758
759- The os module now exports all the symbolic constants usable with the
760 low-level os.open() on Windows: the new constants in 2.3 are
761 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
762 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
763 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
764 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
765 (so specify both if you want both; note that neither is useful unless
766 specified with O_CREAT too).
767
Tim Petersaf8446f2001-12-21 21:36:50 +0000768Mac
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000769----
770
771Yet to be written.
Tim Petersaf8446f2001-12-21 21:36:50 +0000772
773
Tim Peters909c0912001-12-14 23:16:18 +0000774What's New in Python 2.2 final?
Tim Peters909c0912001-12-14 23:16:18 +0000775===============================
776
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000777*Release date: 21-Dec-2001*
778
Tim Peters909c0912001-12-14 23:16:18 +0000779Type/class unification and new-style classes
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000780--------------------------------------------
Tim Peters909c0912001-12-14 23:16:18 +0000781
Barry Warsaw52acb492001-12-21 20:04:22 +0000782- pickle.py, cPickle: allow pickling instances of new-style classes
783 with a custom metaclass.
784
Tim Peters909c0912001-12-14 23:16:18 +0000785Core and builtins
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000786-----------------
Tim Peters909c0912001-12-14 23:16:18 +0000787
Barry Warsaw52acb492001-12-21 20:04:22 +0000788- weakref proxy object: when comparing, unwrap both arguments if both
789 are proxies.
790
Tim Peters909c0912001-12-14 23:16:18 +0000791Extension modules
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000792-----------------
Tim Peters909c0912001-12-14 23:16:18 +0000793
Barry Warsaw52acb492001-12-21 20:04:22 +0000794- binascii.b2a_base64(): fix a potential buffer overrun when encoding
795 very short strings.
796
797- cPickle: the obscure "fast" mode was suspected of causing stack
798 overflows on the Mac. Hopefully fixed this by setting the recursion
799 limit much smaller. If the limit is too low (it only affects
800 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
801 when compiling cPickle.c (or in pyconfig.h).
802
Tim Peters909c0912001-12-14 23:16:18 +0000803Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000804-------
Tim Peters909c0912001-12-14 23:16:18 +0000805
Barry Warsaw52acb492001-12-21 20:04:22 +0000806- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
807 close or delete time).
808
809- rfc822.py: fixed a bug where the address '<>' was converted to None
810 instead of an empty string (also fixes the email.Utils module).
811
812- xmlrpclib.py: version 1.0.0; uses precision for doubles.
813
814- test suite: the pickle and cPickle tests were not executing any code
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000815 when run from the standard regression test.
Barry Warsaw52acb492001-12-21 20:04:22 +0000816
Tim Peters909c0912001-12-14 23:16:18 +0000817Tools/Demos
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000818-----------
Tim Peters909c0912001-12-14 23:16:18 +0000819
820Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000821-----
Tim Peters909c0912001-12-14 23:16:18 +0000822
823C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000824-----
Tim Peters909c0912001-12-14 23:16:18 +0000825
826New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000827-------------
Tim Peters909c0912001-12-14 23:16:18 +0000828
829Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000830-----
Tim Peters909c0912001-12-14 23:16:18 +0000831
832Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000833-------
Tim Peters909c0912001-12-14 23:16:18 +0000834
Barry Warsaw52acb492001-12-21 20:04:22 +0000835- distutils package: fixed broken Windows installers (bdist_wininst).
836
837- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
838 instances are deleted at process exit time.
839
840- socket.py: prevent mysterious warnings when socket instances are
841 deleted at process exit time.
842
843- posixmodule.c: fix a Windows crash with stat() of a filename ending
844 in backslash.
845
Tim Peters909c0912001-12-14 23:16:18 +0000846Mac
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000847----
Tim Peters909c0912001-12-14 23:16:18 +0000848
Barry Warsaw52acb492001-12-21 20:04:22 +0000849- The Carbon toolbox modules have been upgraded to Universal Headers
850 3.4, and experimental CoreGraphics and CarbonEvents modules have
851 been added. All only for framework-enabled MacOSX.
852
Tim Peters909c0912001-12-14 23:16:18 +0000853
Tim Peters6272dfd2001-12-13 19:34:00 +0000854What's New in Python 2.2c1?
Tim Petersb3c9af12001-11-17 00:21:57 +0000855===========================
856
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000857*Release date: 14-Dec-2001*
858
Tim Petersb3c9af12001-11-17 00:21:57 +0000859Type/class unification and new-style classes
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000860--------------------------------------------
Tim Petersb3c9af12001-11-17 00:21:57 +0000861
Barry Warsaw06557452001-12-14 20:47:12 +0000862- Guido's tutorial introduction to the new type/class features has
863 been extensively updated. See
864
865 http://www.python.org/2.2/descrintro.html
866
867 That remains the primary documentation in this area.
868
Guido van Rossum33bab012001-12-05 22:45:48 +0000869- Fixed a leak: instance variables declared with __slots__ were never
870 deleted!
871
Guido van Rossum4b800852001-12-03 00:54:52 +0000872- The "delete attribute" method of descriptor objects is called
873 __delete__, not __del__. In previous releases, it was mistakenly
874 called __del__, which created an unfortunate overloading condition
875 with finalizers. (The "get attribute" and "set attribute" methods
876 are still called __get__ and __set__, respectively.)
877
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000878- Some subtle issues with the super built-in were fixed:
879
880 (a) When super itself is subclassed, its __get__ method would still
881 return an instance of the base class (i.e., of super).
882
883 (b) super(C, C()).__class__ would return C rather than super. This
884 is confusing. To fix this, I decided to change the semantics of
885 super so that it only applies to code attributes, not to data
886 attributes. After all, overriding data attributes is not
887 supported anyway.
888
889 (c) The __get__ method didn't check whether the argument was an
890 instance of the type used in creation of the super instance.
891
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000892- Previously, hash() of an instance of a subclass of a mutable type
893 (list or dictionary) would return some value, rather than raising
894 TypeError. This has been fixed. Also, directly calling
895 dict.__hash__ and list.__hash__ now raises the same TypeError
896 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000897
Guido van Rossumd331cb52001-12-05 19:46:42 +0000898- New-style objects now support deleting their __dict__. This is for
899 all intents and purposes equivalent to assigning a brand new empty
900 dictionary, but saves space if the object is not used further.
901
Tim Petersb3c9af12001-11-17 00:21:57 +0000902Core and builtins
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000903-----------------
Tim Petersb3c9af12001-11-17 00:21:57 +0000904
Tim Peters3caca232001-12-06 06:23:26 +0000905- -Qnew now works as documented in PEP 238: when -Qnew is passed on
906 the command line, all occurrences of "/" use true division instead
907 of classic division. See the PEP for details. Note that "all"
908 means all instances in library and 3rd-party modules, as well as in
909 your own code. As the PEP says, -Qnew is intended for use only in
910 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000911 Note that test_coercion.py in the standard Python test suite fails
912 under -Qnew; this is expected, and won't be repaired until true
913 division becomes the default (in the meantime, test_coercion is
914 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000915
Fred Drake6c01e252001-12-14 17:08:12 +0000916- complex() now only allows the first argument to be a string
917 argument, and raises TypeError if either the second arg is a string
918 or if the second arg is specified when the first is a string.
919
Tim Petersb3c9af12001-11-17 00:21:57 +0000920Extension modules
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000921-----------------
Tim Petersb3c9af12001-11-17 00:21:57 +0000922
Martin v. Löwis560da622001-11-24 09:24:51 +0000923- gc.get_referents was renamed to gc.get_referrers.
924
Tim Petersb3c9af12001-11-17 00:21:57 +0000925Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000926-------
Tim Petersb3c9af12001-11-17 00:21:57 +0000927
Tim Peters25059d32001-12-07 20:35:43 +0000928- Functions in the os.spawn() family now release the global interpreter
929 lock around calling the platform spawn. They should always have done
930 this, but did not before 2.2c1. Multithreaded programs calling
931 an os.spawn function with P_WAIT will no longer block all Python threads
932 until the spawned program completes. It's possible that some programs
933 relies on blocking, although more likely by accident than by design.
934
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000935- webbrowser defaults to netscape.exe on OS/2 now.
936
Martin v. Löwis652e1912001-11-25 14:50:56 +0000937- Tix.ResizeHandle exposes detach_widget, hide, and show.
938
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000939- The charset alias windows_1252 has been added.
940
Barry Warsaw06557452001-12-14 20:47:12 +0000941- types.StringTypes is a tuple containing the defined string types;
942 usually this will be (str, unicode), but if Python was compiled
943 without Unicode support it will be just (str,).
944
945- The pulldom and minidom modules were synchronized to PyXML.
946
Tim Petersb3c9af12001-11-17 00:21:57 +0000947Tools/Demos
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000948-----------
Tim Petersb3c9af12001-11-17 00:21:57 +0000949
Barry Warsaw06557452001-12-14 20:47:12 +0000950- A new script called Tools/scripts/google.py was added, which fires
951 off a search on Google.
952
Tim Petersb3c9af12001-11-17 00:21:57 +0000953Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000954-----
Tim Petersb3c9af12001-11-17 00:21:57 +0000955
Barry Warsaw06557452001-12-14 20:47:12 +0000956- Note that release builds of Python should arrange to define the
957 preprocessor symbol NDEBUG on the command line (or equivalent).
958 In the 2.2 pre-release series we tried to define this by magic in
959 Python.h instead, but it proved to cause problems for extension
960 authors. The Unix, Windows and Mac builds now all define NDEBUG in
961 release builds via cmdline (or equivalent) instead. Ports to
962 other platforms should do likewise.
963
Jack Jansen1999ef42001-12-06 21:47:20 +0000964- It is no longer necessary to use --with-suffix when building on a
965 case-insensitive file system (such as Mac OS X HFS+). In the build
966 directory an extension is used, but not in the installed python.
967
Tim Petersb3c9af12001-11-17 00:21:57 +0000968C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000969-----
Tim Petersb3c9af12001-11-17 00:21:57 +0000970
Tim Petersf582b822001-12-11 18:51:08 +0000971- New function PyDict_MergeFromSeq2() exposes the builtin dict
972 constructor's logic for updating a dictionary from an iterable object
973 producing key-value pairs.
974
Tim Peterscffed4b2001-11-29 03:26:37 +0000975- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000976 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000977 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
978 dump core in some bad cases. This has been repaired. As a result,
979 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
980 previously went unchallenged.
981
Tim Petersb3c9af12001-11-17 00:21:57 +0000982New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000983-------------
Tim Petersb3c9af12001-11-17 00:21:57 +0000984
985Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000986-----
Tim Petersb3c9af12001-11-17 00:21:57 +0000987
988Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000989-------
Tim Petersb3c9af12001-11-17 00:21:57 +0000990
991Mac
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000992----
Tim Petersb3c9af12001-11-17 00:21:57 +0000993
Jack Jansenffa260f2001-12-06 21:14:00 +0000994- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
995 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000996
Barry Warsaw06557452001-12-14 20:47:12 +0000997- Changed logic for finding python home in Mac OS X framework Pythons.
998 Now sys.executable points to the executable again, in stead of to
999 the shared library. The latter is used only for locating the python
1000 home.
1001
1002
Tim Peters84362bc2001-10-19 17:55:30 +00001003What's New in Python 2.2b2?
Tim Peters84362bc2001-10-19 17:55:30 +00001004===========================
1005
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001006*Release date: 16-Nov-2001*
1007
Tim Peters84362bc2001-10-19 17:55:30 +00001008Type/class unification and new-style classes
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001009--------------------------------------------
Tim Peters84362bc2001-10-19 17:55:30 +00001010
Guido van Rossum3d27df02001-11-15 20:27:54 +00001011- Multiple inheritance mixing new-style and classic classes in the
1012 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +00001013
1014 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +00001015 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +00001016
1017 The MRO (method resolution order) for each base class is respected
1018 according to its kind, but the MRO for the derived class is computed
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001019 using new-style MRO rules if any base class is a new-style class.
Tim Peters76f7fe32001-11-15 20:02:21 +00001020 This needs to be documented.
1021
Tim Petersa427a2b2001-10-29 22:25:45 +00001022- The new builtin dictionary() constructor, and dictionary type, have
1023 been renamed to dict. This reflects a decade of common usage.
1024
Guido van Rossum3fc08d22001-11-15 20:33:10 +00001025- dict() now accepts an iterable object producing 2-sequences. For
1026 example, dict(d.items()) == d for any dictionary d. The argument,
1027 and the elements of the argument, can be any iterable objects.
1028
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +00001029- New-style classes can now have a __del__ method, which is called
1030 when the instance is deleted (just like for classic classes).
1031
Guido van Rossum12d955c2001-10-26 14:56:06 +00001032- Assignment to object.__dict__ is now possible, for objects that are
1033 instances of new-style classes that have a __dict__ (unless the base
1034 class forbids it).
1035
Guido van Rossumc8e56452001-10-22 00:43:43 +00001036- Methods of built-in types now properly check for keyword arguments
1037 (formerly these were silently ignored). The only built-in methods
1038 that take keyword arguments are __call__, __init__ and __new__.
1039
Guido van Rossum86443212001-10-27 22:28:54 +00001040- The socket function has been converted to a type; see below.
1041
Tim Peters84362bc2001-10-19 17:55:30 +00001042Core and builtins
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001043-----------------
Tim Peters84362bc2001-10-19 17:55:30 +00001044
Jeremy Hylton249aaed2001-11-09 21:06:24 +00001045- Assignment to __debug__ raises SyntaxError at compile-time. This
1046 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +00001047 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +00001048
Guido van Rossum12d955c2001-10-26 14:56:06 +00001049- Clarified the error messages for unsupported operands to an operator
1050 (like 1 + '').
1051
Tim Peters84362bc2001-10-19 17:55:30 +00001052Extension modules
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001053-----------------
Tim Peters84362bc2001-10-19 17:55:30 +00001054
Tim Peters5ebfd362001-11-13 23:11:19 +00001055- mmap has a new keyword argument, "access", allowing a uniform way for
1056 both Windows and Unix users to create read-only, write-through and
1057 copy-on-write memory mappings. This was previously possible only on
1058 Unix. A new keyword argument was required to support this in a
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001059 uniform way because the mmap() signatures had diverged across
Tim Peters5ebfd362001-11-13 23:11:19 +00001060 platforms. Thanks to Jay T Miller for repairing this!
1061
Tim Peters169ded02001-11-03 19:57:21 +00001062- By default, the gc.garbage list now contains only those instances in
1063 unreachable cycles that have __del__ methods; in 2.1 it contained all
1064 instances in unreachable cycles. "Instances" here has been generalized
1065 to include instances of both new-style and old-style classes.
1066
Guido van Rossum12d955c2001-10-26 14:56:06 +00001067- The socket module defines a new method for socket objects,
1068 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +00001069 send() until all data has been sent. Also, the socket function has
1070 been converted to a subclassable type, like list and tuple (etc.)
1071 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +00001072
1073- Various bugfixes to the curses module. There is now a test suite
1074 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +00001075
Guido van Rossum692adf12001-10-30 03:03:03 +00001076- binascii.b2a_base64 no longer places an arbitrary restriction of 57
1077 bytes on its input.
1078
Tim Peters84362bc2001-10-19 17:55:30 +00001079Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001080-------
Tim Peters84362bc2001-10-19 17:55:30 +00001081
Tim Peters5ebfd362001-11-13 23:11:19 +00001082- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +00001083 convenience function.
1084
Tim Peters75335872001-11-03 19:35:43 +00001085- Symbolic group names in regular expressions must be unique. For
1086 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
1087 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +00001088 Python 2.2 detects this error at regexp compilation time;
1089 previously, the error went undetected, and results were
1090 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
1091 pattern.subn() methods have been rewritten in C. Also, an
1092 experimental function/method finditer() has been added, which works
1093 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +00001094
Martin v. Löwisb7b32602001-11-02 23:48:20 +00001095- Tix exposes more commands through the classes DirSelectBox,
1096 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
1097 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
1098 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
1099
Tim Peters98791af2001-10-23 01:59:54 +00001100- Traceback objects are now scanned by cyclic garbage collection, so
1101 cycles created by casual use of sys.exc_info() no longer cause
1102 permanent memory leaks (provided garbage collection is enabled).
1103
Guido van Rossum49192142001-10-24 20:51:44 +00001104- os.extsep -- a new variable needed by the RISCOS support. It is the
1105 separator used by extensions, and is '.' on all platforms except
1106 RISCOS, where it is '/'. There is no need to use this variable
1107 unless you have a masochistic desire to port your code to RISCOS.
1108
Barry Warsaw012852b2001-11-16 16:17:27 +00001109- mimetypes.py has optional support for non-standard, but commonly
1110 found types. guess_type() and guess_extension() now accept an
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001111 optional 'strict' flag, defaulting to true, which controls whether
Barry Warsaw012852b2001-11-16 16:17:27 +00001112 recognize non-standard types or not. A few non-standard types we
1113 know about have been added. Also, when run as a script, there are
1114 new -l and -e options.
1115
1116- statcache is now deprecated.
1117
1118- email.Utils.formatdate() now produces the preferred RFC 2822 style
1119 dates with numeric timezones (it used to produce obsolete dates
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001120 hard coded to "GMT" timezone). An optional 'localtime' flag is
Barry Warsaw012852b2001-11-16 16:17:27 +00001121 added to produce dates in the local timezone, with daylight savings
1122 time properly taken into account.
1123
1124- In pickle and cPickle, instead of masking errors in load() by
1125 transforming them into SystemError, we let the original exception
1126 propagate out. Also, implement support for __safe_for_unpickling__
1127 in pickle, as it already was supported in cPickle.
1128
Tim Peters84362bc2001-10-19 17:55:30 +00001129Tools/Demos
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001130-----------
Tim Peters84362bc2001-10-19 17:55:30 +00001131
1132Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001133-----
Tim Peters84362bc2001-10-19 17:55:30 +00001134
Barry Warsaw012852b2001-11-16 16:17:27 +00001135- The dbm module is built using libdb1 if available. The bsddb module
1136 is built with libdb3 if available.
1137
1138- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
1139
Tim Peters84362bc2001-10-19 17:55:30 +00001140C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001141-----
Tim Peters84362bc2001-10-19 17:55:30 +00001142
Tim Peters1fc240e2001-10-26 05:06:50 +00001143- New function PySequence_Fast_GET_SIZE() returns the size of a non-
1144 NULL result from PySequence_Fast(), more quickly than calling
1145 PySequence_Size().
1146
Barry Warsaw012852b2001-11-16 16:17:27 +00001147- New argument unpacking function PyArg_UnpackTuple() added.
1148
1149- New functions PyObject_CallFunctionObjArgs() and
1150 PyObject_CallMethodObjArgs() have been added to make it more
1151 convenient and efficient to call functions and methods from C.
1152
1153- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
1154 possible that this will propagate errors it didn't before.
1155
1156- New function PyObject_CheckReadBuffer(), which returns true if its
1157 argument supports the single-segment readable buffer interface.
1158
Tim Peters84362bc2001-10-19 17:55:30 +00001159New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001160-------------
Tim Peters84362bc2001-10-19 17:55:30 +00001161
Guido van Rossum86443212001-10-27 22:28:54 +00001162- We've finally confirmed that this release builds on HP-UX 11.00,
1163 *with* threads, and passes the test suite.
1164
Tim Peters7a33d8b2001-11-05 02:51:07 +00001165- Thanks to a series of patches from Michael Muller, Python may build
1166 again under OS/2 Visual Age C++.
1167
Guido van Rossum49192142001-10-24 20:51:44 +00001168- Updated RISCOS port by Dietmar Schwertberger.
1169
Tim Peters84362bc2001-10-19 17:55:30 +00001170Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001171-----
Tim Peters84362bc2001-10-19 17:55:30 +00001172
Andrew M. Kuchling15e03532001-10-22 16:37:10 +00001173- Added a test script for the curses module. It isn't run automatically;
1174 regrtest.py must be run with '-u curses' to enable it.
1175
Tim Peters84362bc2001-10-19 17:55:30 +00001176Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001177-------
Tim Peters84362bc2001-10-19 17:55:30 +00001178
Barry Warsaw012852b2001-11-16 16:17:27 +00001179Mac
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001180----
Barry Warsaw012852b2001-11-16 16:17:27 +00001181
1182- PythonScript has been moved to unsupported and is slated to be
1183 removed completely in the next release.
1184
1185- It should now be possible to build applets that work on both OS9 and
1186 OSX.
1187
1188- The core is now linked with CoreServices not Carbon; as a side
1189 result, default 8bit encoding on OSX is now ASCII.
1190
1191- Python should now build on OSX 10.1.1
1192
Tim Peters84362bc2001-10-19 17:55:30 +00001193
Tim Petersabf925f2001-09-28 21:53:42 +00001194What's New in Python 2.2b1?
Tim Petersabf925f2001-09-28 21:53:42 +00001195===========================
1196
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001197*Release date: 19-Oct-2001*
1198
Tim Petersabf925f2001-09-28 21:53:42 +00001199Type/class unification and new-style classes
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001200--------------------------------------------
Tim Petersabf925f2001-09-28 21:53:42 +00001201
Guido van Rossum687ae002001-10-15 22:03:32 +00001202- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001203 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +00001204 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001205 remains: the __dict__ of a new-style class is a read-only proxy; you
1206 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +00001207 __defined__ attribute of new-style types no longer exists, for lack
1208 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001209 future a __cache__ may be resurrected with a similar function, if I
1210 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +00001211
Tim Peters1c9ca872001-10-04 06:43:12 +00001212- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
1213 always returned None, even when there was a class docstring).
1214
1215- doctest now finds and runs docstrings attached to new-style classes,
1216 class methods, static methods, and properties.
1217
Guido van Rossum9074ef62001-10-16 21:34:49 +00001218Core and builtins
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001219-----------------
Tim Petersabf925f2001-09-28 21:53:42 +00001220
Guido van Rossuma8bcf802001-10-15 15:53:58 +00001221- A very subtle syntactical pitfall in list comprehensions was fixed.
1222 For example: [a+b for a in 'abc', for b in 'def']. The comma in
1223 this example is a mistake. Previously, this would silently let 'a'
1224 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
1225 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
1226 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
1227 Note that [a for a in <singleton>] is a convoluted way to say
1228 [<singleton>] anyway, so it's not like any expressiveness is lost.
1229
Guido van Rossum9074ef62001-10-16 21:34:49 +00001230- getattr(obj, name, default) now only catches AttributeError, as
1231 documented, rather than returning the default value for all
1232 exceptions (which could mask bugs in a __getattr__ hook, for
1233 example).
1234
Fred Drakecb7a6b52001-10-22 18:41:51 +00001235- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +00001236 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001237 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +00001238 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +00001239
Guido van Rossum1c486092001-10-19 02:05:35 +00001240- unicode(obj) now behaves more like str(obj), accepting arbitrary
1241 objects, and calling a __unicode__ method if it exists.
1242 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +00001243 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +00001244
Barry Warsawf6fb1712001-10-19 05:35:40 +00001245- isinstance() now allows any object as the first argument and a
1246 class, a type or something with a __bases__ tuple attribute for the
1247 second argument. The second argument may also be a tuple of a
1248 class, type, or something with __bases__, in which case isinstance()
1249 will return true if the first argument is an instance of any of the
1250 things contained in the second argument tuple. E.g.
1251
1252 isinstance(x, (A, B))
1253
1254 returns true if x is an instance of A or B.
1255
Guido van Rossum9074ef62001-10-16 21:34:49 +00001256Extension modules
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001257-----------------
Guido van Rossum9074ef62001-10-16 21:34:49 +00001258
1259- thread.start_new_thread() now returns the thread ID (previously None).
1260
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001261- binascii has now two quopri support functions, a2b_qp and b2a_qp.
1262
Guido van Rossumc524d952001-10-19 01:31:59 +00001263- readline now supports setting the startup_hook and the
1264 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +00001265
Guido van Rossumc524d952001-10-19 01:31:59 +00001266- os and posix supports chroot(), setgroups() and unsetenv() where
1267 available. The stat(), fstat(), statvfs() and fstatvfs() functions
1268 now return "pseudo-sequences" -- the various fields can now be
1269 accessed as attributes (e.g. os.stat("/").st_mtime) but for
1270 backwards compatibility they also behave as a fixed-length sequence.
1271 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +00001272 attributes.
1273
1274- time: localtime(), gmtime() and strptime() now return a
1275 pseudo-sequence similar to the os.stat() return value, with
1276 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +00001277
Guido van Rossum9074ef62001-10-16 21:34:49 +00001278- Decompression objects in the zlib module now accept an optional
1279 second parameter to decompress() that specifies the maximum amount
1280 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +00001281
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001282- optional SSL support in the socket module now exports OpenSSL
1283 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
1284 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +00001285 automatically seed its PRNG. Also, the keyfile and certfile
1286 arguments to socket.ssl() are now optional.
1287
1288- posixmodule (and by extension, the os module on POSIX platforms) now
1289 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001290
Guido van Rossum9074ef62001-10-16 21:34:49 +00001291Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001292-------
Guido van Rossum3c288632001-10-16 21:13:49 +00001293
Tim Peters7402f792001-10-02 03:53:41 +00001294- doctest now excludes functions and classes not defined by the module
1295 being tested, thanks to Tim Hochberg.
1296
Fred Drakecb7a6b52001-10-22 18:41:51 +00001297- HotShot, a new profiler implemented using a C-based callback, has
1298 been added. This substantially reduces the overhead of profiling,
1299 but it is still quite preliminary. Support modules and
1300 documentation will be added in upcoming releases (before 2.2 final).
1301
Guido van Rossumc4b09b42001-10-04 10:19:00 +00001302- profile now produces correct output in situations where an exception
1303 raised in Python is cleared by C code (e.g. hasattr()). This used
1304 to cause wrong output, including spurious claims of recursive
1305 functions and attribution of time spent to the wrong function.
1306
Tim Peters0a1fc4e2001-10-07 03:12:08 +00001307 The code and documentation for the derived OldProfile and HotProfile
1308 profiling classes was removed. The code hasn't worked for years (if
1309 you tried to use them, they raised exceptions). OldProfile
1310 intended to reproduce the behavior of the profiler Python used more
1311 than 7 years ago, and isn't interesting anymore. HotProfile intended
1312 to provide a faster profiler (but producing less information), and
1313 that's a worthy goal we intend to meet via a different approach (but
1314 without losing information).
1315
Tim Peterscce092d2001-10-09 05:31:56 +00001316- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +00001317 a much better system-specific calibration constant. The constant can
1318 now be specified in an instance constructor, or as a Profile class or
1319 instance variable, instead of by editing profile.py's source code.
1320 Calibration must still be done manually (see the docs for the profile
1321 module).
1322
1323 Note that Profile.calibrate() must be overriden by subclasses.
1324 Improving the accuracy required exploiting detailed knowledge of
1325 profiler internals; the earlier method abstracted away the details
1326 and measured a simplified model instead, but consequently computed
1327 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +00001328
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001329- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +00001330 which indicates whether output is intended for the header 'Q'
1331 encoding.
1332
Guido van Rossuma5343cc2001-10-18 18:02:07 +00001333- The SocketServer.ThreadingMixIn class now closes the request after
1334 finish_request() returns. (Not when it errors out though.)
1335
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001336- The nntplib module's NNTP.body() method has grown a 'file' argument
Barry Warsawf6fb1712001-10-19 05:35:40 +00001337 to allow saving the message body to a file.
1338
1339- The email package has added a class email.Parser.HeaderParser which
1340 only parses headers and does not recurse into the message's body.
1341 Also, the module/class MIMEAudio has been added for representing
1342 audio data (contributed by Anthony Baxter).
1343
1344- ftplib should be able to handle files > 2GB.
1345
1346- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
1347 ON, and OFF.
1348
Fred Drakecb7a6b52001-10-22 18:41:51 +00001349- xml.dom.minidom NodeList objects now support the length attribute
1350 and item() method as required by the DOM specifications.
1351
Guido van Rossumed554f62001-10-02 23:15:37 +00001352Tools/Demos
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001353-----------
Guido van Rossumed554f62001-10-02 23:15:37 +00001354
1355- Demo/dns was removed. It no longer serves any purpose; a package
1356 derived from it is now maintained by Anthony Baxter, see
1357 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +00001358
Barry Warsawf6fb1712001-10-19 05:35:40 +00001359- The freeze tool has been made more robust, and two new options have
1360 been added: -X and -E.
1361
Tim Petersabf925f2001-09-28 21:53:42 +00001362Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001363-----
Tim Petersabf925f2001-09-28 21:53:42 +00001364
Barry Warsawf6fb1712001-10-19 05:35:40 +00001365- configure will use CXX in LINKCC if CXX is used to build main() and
1366 the system requires to link a C++ main using the C++ compiler.
1367
Tim Petersabf925f2001-09-28 21:53:42 +00001368C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001369-----
Tim Petersabf925f2001-09-28 21:53:42 +00001370
Guido van Rossum6c4bce32001-10-18 19:20:25 +00001371- The documentation for the tp_compare slot is updated to require that
1372 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
1373 not correct. This is not yet enforced but will be enforced in
1374 Python 2.3; even later, we may use -2 to indicate errors and +2 for
1375 "NotImplemented". Right now, -1 should be used for an error return.
1376
Tim Petersd38b1c72001-09-30 05:09:37 +00001377- PyLong_AsLongLong() now accepts int (as well as long) arguments.
1378 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
1379 as long) arguments.
1380
Guido van Rossum3c288632001-10-16 21:13:49 +00001381- PyThread_start_new_thread() now returns a long int giving the thread
1382 ID, if one can be calculated; it returns -1 for error, 0 if no
1383 thread ID is calculated (this is an incompatible change, but only
1384 the thread module used this API). This code has only really been
1385 tested on Linux and Windows; other platforms please beware (and
1386 report any bugs or strange behavior).
1387
Guido van Rossum1c486092001-10-19 02:05:35 +00001388- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
1389 input.
1390
Tim Petersabf925f2001-09-28 21:53:42 +00001391New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001392-------------
Tim Petersabf925f2001-09-28 21:53:42 +00001393
1394Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001395-----
Tim Petersabf925f2001-09-28 21:53:42 +00001396
1397Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001398-------
Tim Petersabf925f2001-09-28 21:53:42 +00001399
Tim Peters04cf1d32001-10-09 22:39:40 +00001400- Installer: If you install IDLE, and don't disable file-extension
1401 registration, a new "Edit with IDLE" context (right-click) menu entry
1402 is created for .py and .pyw files.
1403
Tim Peters1ce3cf72001-10-01 17:58:40 +00001404- The signal module now supports SIGBREAK on Windows, thanks to Steven
1405 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
1406 action remains to call Win32 ExitProcess(). This can be changed via
Skip Montanaroa2a07bc2002-09-30 15:23:01 +00001407 signal.signal(). For example::
Tim Peters1ce3cf72001-10-01 17:58:40 +00001408
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001409 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
1410 # (SIGINT) behavior.
1411 import signal
1412 signal.signal(signal.SIGBREAK, signal.default_int_handler)
Tim Peters1ce3cf72001-10-01 17:58:40 +00001413
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001414 try:
1415 while 1:
1416 pass
1417 except KeyboardInterrupt:
1418 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
1419 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
1420 # program without the possibility for any Python-level cleanup).
1421 print "Clean exit"
Tim Peters1ce3cf72001-10-01 17:58:40 +00001422
Tim Petersabf925f2001-09-28 21:53:42 +00001423
Tim Petersb07352e2001-09-08 01:25:47 +00001424What's New in Python 2.2a4?
1425===========================
1426
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001427*Release date: 28-Sep-2001*
1428
Guido van Rossum808eea72001-09-25 04:15:41 +00001429Type/class unification and new-style classes
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001430--------------------------------------------
Guido van Rossum808eea72001-09-25 04:15:41 +00001431
1432- pydoc and inspect are now aware of new-style classes;
1433 e.g. help(list) at the interactive prompt now shows proper
1434 documentation for all operations on list objects.
1435
1436- Applications using Jim Fulton's ExtensionClass module can now safely
1437 be used with Python 2.2. In particular, Zope 2.4.1 now works with
1438 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
1439 examples also work again. It is hoped that Gtk and Boost also work
1440 with 2.2a4 and beyond. (If you can confirm this, please write
1441 webmaster@python.org; if there are still problems, please open a bug
1442 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +00001443
Tim Peters66c1a522001-09-24 21:17:50 +00001444- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001445 These map to read-only attributes 'fget', 'fset', 'fdel', and '__doc__'
Tim Peters66c1a522001-09-24 21:17:50 +00001446 in the constructed property object. fget, fset and fdel weren't
1447 discoverable from Python in 2.2a3. __doc__ is new, and allows to
1448 associate a docstring with a property.
1449
Guido van Rossum808eea72001-09-25 04:15:41 +00001450- Comparison overloading is now more completely implemented. For
1451 example, a str subclass instance can properly be compared to a str
1452 instance, and it can properly overload comparison. Ditto for most
1453 other built-in object types.
1454
1455- The repr() of new-style classes has changed; instead of <type
1456 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
1457 *except* for built-in types, which are still rendered as <type
1458 'Foo'> (to avoid upsetting existing code that might parse or
1459 otherwise rely on repr() of certain type objects).
1460
1461- The repr() of new-style objects is now always <Foo object at XXX>;
1462 previously, it was sometimes <Foo instance at XXX>.
1463
1464- For new-style classes, what was previously called __getattr__ is now
1465 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001466 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +00001467 one in classic classes is defined which is called only if regular
1468 attribute access raises AttributeError; to catch *all* attribute
1469 access, you can use __getattribute__ (for new-style classes). If
1470 both are defined, __getattribute__ is called first, and if it raises
1471 AttributeError, __getattr__ is called.
1472
1473- The __class__ attribute of new-style objects can be assigned to.
1474 The new class must have the same C-level object layout as the old
1475 class.
1476
1477- The builtin file type can be subclassed now. In the usual pattern,
1478 "file" is the name of the builtin type, and file() is a new builtin
1479 constructor, with the same signature as the builtin open() function.
1480 file() is now the preferred way to open a file.
1481
1482- Previously, __new__ would only see sequential arguments passed to
1483 the type in a constructor call; __init__ would see both sequential
1484 and keyword arguments. This made no sense whatsoever any more, so
1485 now both __new__ and __init__ see all arguments.
1486
1487- Previously, hash() applied to an instance of a subclass of str or
1488 unicode always returned 0. This has been repaired.
1489
1490- Previously, an operation on an instance of a subclass of an
1491 immutable type (int, long, float, complex, tuple, str, unicode),
1492 where the subtype didn't override the operation (and so the
1493 operation was handled by the builtin type), could return that
1494 instance instead a value of the base type. For example, if s was of
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001495 a str subclass type, s[:] returned s as-is. Now it returns a str
Guido van Rossum808eea72001-09-25 04:15:41 +00001496 with the same value as s.
1497
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001498- Provisional support for pickling new-style objects has been added.
1499
Guido van Rossum808eea72001-09-25 04:15:41 +00001500Core
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001501----
Guido van Rossum808eea72001-09-25 04:15:41 +00001502
Tim Peters2c9aa5e2001-09-23 04:06:05 +00001503- file.writelines() now accepts any iterable object producing strings.
1504
Marc-André Lemburgaefd7662001-09-20 12:59:37 +00001505- PyUnicode_FromEncodedObject() now works very much like
1506 PyObject_Str(obj) in that it tries to use __str__/tp_str
1507 on the object if the object is not a string or buffer. This
1508 makes unicode() behave like str() when applied to non-string/buffer
1509 objects.
1510
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001511- PyFile_WriteObject now passes Unicode objects to the file's write
1512 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +00001513 of a print statement must support Unicode objects, i.e. they must
1514 at least convert them into ASCII strings.
1515
Guido van Rossum624c8af2001-09-18 15:21:04 +00001516- Thread scheduling on Solaris should be improved; it is no longer
1517 necessary to insert a small sleep at the start of a thread in order
1518 to let other runnable threads be scheduled.
1519
Tim Petersb07352e2001-09-08 01:25:47 +00001520Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001521-------
Tim Petersb07352e2001-09-08 01:25:47 +00001522
Marc-André Lemburgbf990172001-09-27 14:17:33 +00001523- StringIO.StringIO instances and cStringIO.StringIO instances support
1524 read character buffer compatible objects for their .write() methods.
1525 These objects are converted to strings and then handled as such
1526 by the instances.
1527
Barry Warsaw2f600732001-09-24 04:28:10 +00001528- The "email" package has been added. This is basically a port of the
1529 mimelib package <http://sf.net/projects/mimelib> with API changes
1530 and some implementations updated to use iterators and generators.
1531
Tim Peters8a9c2842001-09-22 21:30:22 +00001532- difflib.ndiff() and difflib.Differ.compare() are generators now. This
1533 restores the ability of Tools/scripts/ndiff.py to start producing output
1534 before the entire comparison is complete.
1535
Barry Warsaw58b072d2001-09-22 04:44:21 +00001536- StringIO.StringIO instances and cStringIO.StringIO instances support
1537 iteration just like file objects (i.e. their .readline() method is
1538 called for each iteration until it returns an empty string).
1539
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +00001540- The codecs module has grown four new helper APIs to access
1541 builtin codecs: getencoder(), getdecoder(), getreader(),
1542 getwriter().
1543
Guido van Rossum624c8af2001-09-18 15:21:04 +00001544- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
1545 simplifies writing XML RPC servers.
1546
Barry Warsaw647d5e82001-09-28 17:01:02 +00001547- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +00001548 after interpretation of symbolic links. On non-Unix systems, this
1549 is an alias for os.path.abspath().
1550
Tim Peters16a77ad2001-09-08 04:00:12 +00001551- operator.indexOf() (PySequence_Index() in the C API) now works with any
1552 iterable object.
1553
Guido van Rossum624c8af2001-09-18 15:21:04 +00001554- smtplib now supports various authentication and security features of
1555 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001556
Guido van Rossum624c8af2001-09-18 15:21:04 +00001557- hmac: a new module implementing keyed hashing for message
1558 authentication.
1559
1560- mimetypes now recognizes more extensions and file types. At the
1561 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001562
Guido van Rossum624c8af2001-09-18 15:21:04 +00001563- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001564 Python 2.2 bytecode generation. It has also been promoted from a
1565 Tool to a standard library package. (Tools/compiler still exists as
1566 a sample driver.)
1567
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001568Tools
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001569-----
Guido van Rossum624c8af2001-09-18 15:21:04 +00001570
Tim Petersb07352e2001-09-08 01:25:47 +00001571Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001572-----
Tim Petersb07352e2001-09-08 01:25:47 +00001573
Guido van Rossum624c8af2001-09-18 15:21:04 +00001574- Large file support (LFS) is now automatic when the platform supports
1575 it; no more manual configuration tweaks are needed. On Linux, at
1576 least, it's possible to have a system whose C library supports large
1577 files but whose kernel doesn't; in this case, large file support is
1578 still enabled but doesn't do you any good unless you upgrade your
1579 kernel or share your Python executable with another system whose
1580 kernel has large file support.
1581
1582- The configure script now supplies plausible defaults in a
1583 cross-compilation environment. This doesn't mean that the supplied
1584 values are always correct, or that cross-compilation now works
1585 flawlessly -- but it's a first step (and it shuts up most of
1586 autoconf's warnings about AC_TRY_RUN).
1587
1588- The Unix build is now a bit less chatty, courtesy of the parser
1589 generator. The build is completely silent (except for errors) when
1590 using "make -s", thanks to a -q option to setup.py.
1591
Tim Petersb07352e2001-09-08 01:25:47 +00001592C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001593-----
Tim Petersb07352e2001-09-08 01:25:47 +00001594
Guido van Rossum624c8af2001-09-18 15:21:04 +00001595- The "structmember" API now supports some new flag bits to deny read
1596 and/or write access to attributes in restricted execution mode.
1597
Tim Petersb07352e2001-09-08 01:25:47 +00001598New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001599-------------
Tim Petersb07352e2001-09-08 01:25:47 +00001600
Guido van Rossum624c8af2001-09-18 15:21:04 +00001601- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1602 (http://familiar.handhelds.org).
1603
Tim Petersb07352e2001-09-08 01:25:47 +00001604Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001605-----
Tim Petersb07352e2001-09-08 01:25:47 +00001606
Tim Peters8a9c2842001-09-22 21:30:22 +00001607- The "classic" standard tests, which work by comparing stdout to
1608 an expected-output file under Lib/test/output/, no longer stop at
1609 the first mismatch. Instead the test is run to completion, and a
1610 variant of ndiff-style comparison is used to report all differences.
1611 This is much easier to understand than the previous style of reporting.
1612
1613- The unittest-based standard tests now use regrtest's test_main()
1614 convention, instead of running as a side-effect of merely being
1615 imported. This allows these tests to be run in more natural and
1616 flexible ways as unittests, outside the regrtest framework.
1617
1618- regrtest.py is much better integrated with unittest and doctest now,
1619 especially in regard to reporting errors.
1620
Tim Petersb07352e2001-09-08 01:25:47 +00001621Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001622-------
Tim Petersb07352e2001-09-08 01:25:47 +00001623
Guido van Rossum624c8af2001-09-18 15:21:04 +00001624- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001625 that support it (NTFS under Windows 2000). See "What's New in
1626 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001627
Tim Petersb07352e2001-09-08 01:25:47 +00001628
Tim Petersedc99312001-08-22 21:36:50 +00001629What's New in Python 2.2a3?
1630===========================
1631
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001632*Release Date: 07-Sep-2001*
1633
Tim Petersedc99312001-08-22 21:36:50 +00001634Core
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001635----
Tim Petersedc99312001-08-22 21:36:50 +00001636
Tim Peters9fffa3e2001-09-04 05:14:19 +00001637- Conversion of long to float now raises OverflowError if the long is too
1638 big to represent as a C double.
1639
Tim Peters32f453e2001-09-03 08:35:41 +00001640- The 3-argument builtin pow() no longer allows a third non-None argument
1641 if either of the first two arguments is a float, or if both are of
1642 integer types and the second argument is negative (in which latter case
1643 the arguments are converted to float, so this is really the same
1644 restriction).
1645
Tim Peters5d2b77c2001-09-03 05:47:38 +00001646- The builtin dir() now returns more information, and sometimes much
1647 more, generally naming all attributes of an object, and all attributes
1648 reachable from the object via its class, and from its class's base
1649 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1650 an empty list. In 2.2a3,
1651
1652 >>> dir([])
1653 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1654 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1655 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1656 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1657 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1658 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1659 'reverse', 'sort']
1660
1661 dir(module) continues to return only the module's attributes, though.
1662
Tim Petersbdee63f2001-09-02 03:40:59 +00001663- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001664 than raising OverflowError. This is a partial implementation of PEP
1665 237. You can use -Wdefault::OverflowWarning to enable a warning for
1666 this situation, and -Werror::OverflowWarning to revert to the old
1667 OverflowError exception.
1668
Guido van Rossum61c345f2001-09-04 03:26:15 +00001669- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001670 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001671 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1672 -Qold, meaning the / operator has its classic meaning and no
1673 warnings are issued. Using -Qwarn issues a run-time warning about
1674 all uses of classic division for int and long arguments; -Qwarnall
1675 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001676 (for use with fixdiv.py).
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001677 [Note: the remainder of this item (preserved below) became
1678 obsolete in 2.2c1 -- -Qnew has global effect in 2.2] ::
1679
1680 Using -Qnew is questionable; it turns on new division by default, but
1681 only in the __main__ module. You can usefully combine -Qwarn or
1682 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1683 warns about classic division everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +00001684
Tim Petersbdee63f2001-09-02 03:40:59 +00001685- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001686 long, float, str, unicode, and tuple. (The types complex, list and
1687 dictionary can also be subclassed; this was introduced earlier.)
1688 Note that restrictions apply when subclassing immutable built-in
1689 types: you can only affect the value of the instance by overloading
1690 __new__. You can add mutable attributes, and the subclass instances
1691 will have a __dict__ attribute, but you cannot change the "value"
1692 (as implemented by the base class) of an immutable subclass instance
1693 once it is created.
1694
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001695- The dictionary constructor now takes an optional argument, a
1696 mapping-like object, and initializes the dictionary from its
1697 (key, value) pairs.
1698
Tim Petersbdee63f2001-09-02 03:40:59 +00001699- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001700 "cooperative super calls" in a multiple inheritance setting. For an
1701 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1702
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001703- A new built-in type, property, has been added. This enables the
1704 creation of "properties". These are attributes implemented by
1705 getter and setter functions (or only one of these for read-only or
1706 write-only attributes), without the need to override __getattr__.
1707 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001708
Tim Petersbdee63f2001-09-02 03:40:59 +00001709- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001710 liberalized, to allow leading zeroes. Examples of literals now
1711 legal that were SyntaxErrors before:
1712
1713 00.0 0e3 0100j 07.5 00000000000000000008.
1714
Tim Petersbdee63f2001-09-02 03:40:59 +00001715- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001716 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1717
Tim Petersedc99312001-08-22 21:36:50 +00001718Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001719-------
Tim Petersedc99312001-08-22 21:36:50 +00001720
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001721- telnetlib includes symbolic names for the options, and support for
Martin v. Löwis1da9c572002-11-04 09:56:00 +00001722 setting an option negotiation callback. It also supports processing
1723 of suboptions.
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001724
Tim Petersa40c7932001-09-05 22:36:56 +00001725- The new C standard no longer requires that math libraries set errno to
1726 ERANGE on overflow. For platform libraries that exploit this new
1727 freedom, Python's overflow-checking was wholly broken. A new overflow-
1728 checking scheme attempts to repair that, but may not be reliable on all
1729 platforms (C doesn't seem to provide anything both useful and portable
1730 in this area anymore).
1731
Martin v. Löwis44f86962001-09-05 13:44:54 +00001732- Asynchronous timeout actions are available through the new class
1733 threading.Timer.
1734
Tim Peters78526162001-09-05 00:53:45 +00001735- math.log and math.log10 now return sensible results for even huge
1736 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1737
Tim Petersbdee63f2001-09-02 03:40:59 +00001738- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001739 currently held. See the docs for the imp module.
1740
Tim Petersbdee63f2001-09-02 03:40:59 +00001741- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001742 dumps containing ints written on platforms where Python ints are 8 bytes.
1743 When read on a box where Python ints are 4 bytes, such values are
1744 converted to Python longs.
1745
Tim Petersbdee63f2001-09-02 03:40:59 +00001746- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001747 code objects is no longer allowed. This plugs a security hole.
1748
Steve Purcell6091cd62001-09-06 16:05:17 +00001749- unittest.TestResult instances no longer store references to tracebacks
1750 generated by test failures. This prevents unexpected dangling references
1751 to objects that should be garbage collected between tests.
1752
Tim Petersedc99312001-08-22 21:36:50 +00001753Tools
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001754-----
Tim Petersedc99312001-08-22 21:36:50 +00001755
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001756- Tools/scripts/fixdiv.py has been added which can be used to fix
1757 division operators as per PEP 238.
1758
Tim Petersedc99312001-08-22 21:36:50 +00001759Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001760-----
Tim Petersedc99312001-08-22 21:36:50 +00001761
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001762- If you are an adventurous person using Mac OS X you may want to look at
1763 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1764 application, which can be used for experimenting with Carbon or Cocoa.
1765 Discussion of this on pythonmac-sig, please.
1766
Tim Peters7eea37e2001-09-04 22:08:56 +00001767C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001768-----
Tim Peters7eea37e2001-09-04 22:08:56 +00001769
1770- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001771
Tim Peters9fffa3e2001-09-04 05:14:19 +00001772- Note that PyLong_AsDouble can fail! This has always been true, but no
1773 callers checked for it. It's more likely to fail now, because overflow
Skip Montanaroa2a07bc2002-09-30 15:23:01 +00001774 errors are properly detected now. The proper way to check::
Tim Peters9fffa3e2001-09-04 05:14:19 +00001775
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001776 double x = PyLong_AsDouble(some_long_object);
1777 if (x == -1.0 && PyErr_Occurred()) {
1778 /* The conversion failed. */
1779 }
Tim Peters9fffa3e2001-09-04 05:14:19 +00001780
Tim Petersbdee63f2001-09-02 03:40:59 +00001781- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001782 compile but will not participate in GC. To upgrade an extension
1783 module:
1784
1785 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001786
Neil Schemenauer4042c692001-08-30 15:38:01 +00001787 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1788 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001789
Neil Schemenauer4042c692001-08-30 15:38:01 +00001790 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1791 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001792
Neil Schemenauer4042c692001-08-30 15:38:01 +00001793 - remove PyGC_HEAD_SIZE from object size calculations
1794
1795 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1796
Tim Petersbdee63f2001-09-02 03:40:59 +00001797- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001798 These can be used safely to construct string objects from a
1799 sprintf-style format string (similar to the format string supported
1800 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001801
Tim Petersedc99312001-08-22 21:36:50 +00001802New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001803-------------
Tim Petersedc99312001-08-22 21:36:50 +00001804
Tim Petersb7da0902001-09-02 23:01:43 +00001805- Stephen Hansen contributed patches sufficient to get a clean compile
1806 under Borland C (Windows), but he reports problems running it and ran
1807 out of time to complete the port. Volunteers? Expect a MemoryError
1808 when importing the types module; this is probably shallow, and
1809 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001810
Tim Petersedc99312001-08-22 21:36:50 +00001811Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001812-----
Tim Petersedc99312001-08-22 21:36:50 +00001813
1814Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001815-------
Tim Petersedc99312001-08-22 21:36:50 +00001816
Tim Peters6e13a562001-09-06 00:32:15 +00001817- Large file support is now enabled on Win32 platforms as well as on
1818 Win64. This means that, for example, you can use f.tell() and f.seek()
1819 to manipulate files larger than 2 gigabytes (provided you have enough
1820 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001821 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1822 filesize limit, and large file support makes no difference there.
1823 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1824 NTFS has no practical limit on file size, and files of any size can be
1825 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001826
Tim Petersbdee63f2001-09-02 03:40:59 +00001827- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001828 points to command.com (patch from Brian Quinlan).
1829
Tim Petersedc99312001-08-22 21:36:50 +00001830
Tim Peters20f51a72001-07-21 02:31:40 +00001831What's New in Python 2.2a2?
1832===========================
1833
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001834*Release Date: 22-Aug-2001*
1835
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001836Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001837-----
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001838
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001839- Tim Peters developed a brand new Windows installer using Wise 8.1,
1840 generously donated to us by Wise Solutions.
1841
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001842- configure supports a new option --enable-unicode, with the values
1843 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1844 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001845
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001846- A new configure option --enable-framework builds a Mac OS X framework,
1847 which "make frameworkinstall" will install. This provides a starting
1848 point for more mac-like functionality, join pythonmac-sig@python.org
1849 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001850
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001851- The NeXT platform is no longer supported.
1852
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001853- The 'new' module is now statically linked.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001854
Tim Peters0afb6092001-08-15 06:06:44 +00001855Tools
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001856-----
Tim Peters0afb6092001-08-15 06:06:44 +00001857
1858- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001859 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001860 the module docstring for details.
1861
Tim Peters20f51a72001-07-21 02:31:40 +00001862Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001863-----
Tim Peters20f51a72001-07-21 02:31:40 +00001864
Tim Peters5e824c32001-08-12 22:25:01 +00001865- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001866 platforms, allowing to give clearer test result output. regrtest
1867 also has optional --use/-u switch to run normally disabled tests
1868 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001869
Tim Peters20f51a72001-07-21 02:31:40 +00001870- Several new tests in the standard test suite, with special thanks to
1871 Nick Mathewson.
1872
1873Core
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001874----
Tim Peters20f51a72001-07-21 02:31:40 +00001875
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001876- The floor division operator // has been added as outlined in PEP
1877 238. The / operator still provides classic division (and will until
1878 Python 3.0) unless "from __future__ import division" is included, in
1879 which case the / operator will provide true division. The operator
1880 module provides truediv() and floordiv() functions. Augmented
1881 assignment variants are included, as are the equivalent overloadable
1882 methods and C API methods. See the PEP for a full discussion:
1883 <http://python.sf.net/peps/pep-0238.html>
1884
Tim Peters6cd6a822001-08-17 22:11:27 +00001885- Future statements are now effective in simulated interactive shells
1886 (like IDLE). This should "just work" by magic, but read Michael
1887 Hudson's "Future statements in simulated shells" PEP 264 for full
1888 details: <http://python.sf.net/peps/pep-0264.html>.
1889
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001890- The type/class unification (PEP 252-253) was integrated into the
1891 trunk and is not so tentative any more (the exact specification of
1892 some features is still tentative). A lot of work has done on fixing
1893 bugs and adding robustness and features (performance still has to
1894 come a long way).
1895
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001896- Warnings about a mismatch in the Python API during extension import
1897 now use the Python warning framework (which makes it possible to
1898 write filters for these warnings).
1899
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001900- A function's __dict__ (aka func_dict) will now always be a
1901 dictionary. It used to be possible to delete it or set it to None,
1902 but now both actions raise TypeErrors. It is still legal to set it
1903 to a dictionary object. Getting func.__dict__ before any attributes
1904 have been assigned now returns an empty dictionary instead of None.
1905
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001906- A new command line option, -E, was added which disables the use of
1907 all environment variables, or at least those that are specifically
1908 significant to Python. Usually those have a name starting with
1909 "PYTHON". This was used to fix a problem where the tests fail if
1910 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1911 older distribution.
1912
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001913Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001914-------
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001915
Tim Peters5e824c32001-08-12 22:25:01 +00001916- New class Differ and new functions ndiff() and restore() in difflib.py.
1917 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001918 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001919
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001920- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1921 value using the minimal quoting required for the value; more
1922 reliable than using xml.sax.saxutils.escape() for attribute values.
1923
1924- Readline completion support for cmd.Cmd was added.
1925
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001926- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1927
1928- Added function threading.BoundedSemaphore()
1929
1930- Added Ka-Ping Yee's cgitb.py module.
1931
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001932- The 'new' module now exposes the CO_xxx flags.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001933
Martin v. Löwis560da622001-11-24 09:24:51 +00001934- The gc module offers the get_referents function.
1935
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001936New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001937-------------
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001938
1939C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001940-----
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001941
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001942- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1943 which provide a cross-platform implementations for the
1944 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1945 the standard sprintf() and vsprintf() C lib APIs, these versions
1946 apply bounds checking on the used buffer which enhances protection
1947 against buffer overruns.
1948
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001949- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001950 and extensions using different Unicode widths is rendered next to
1951 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001952 will result in an ImportError. Unicode extensions writers must make
1953 sure to check the Unicode width compatibility in their extensions by
1954 using at least one of the mangled Unicode APIs in the extension.
1955
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001956- Two new flags METH_NOARGS and METH_O are available in method definition
1957 tables to simplify implementation of methods with no arguments and a
1958 single untyped argument. Calling such methods is more efficient than
1959 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1960 deprecated.
1961
Tim Petersc1731372001-08-04 08:12:36 +00001962Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001963-------
Tim Petersc1731372001-08-04 08:12:36 +00001964
1965- "import module" now compiles module.pyw if it exists and nothing else
1966 relevant is found.
1967
Tim Peters20f51a72001-07-21 02:31:40 +00001968
Guido van Rossum55a78992001-07-17 17:22:32 +00001969What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +00001970===========================
1971
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001972*Release date: 18-Jul-2001*
1973
Tim Petersf553f892001-05-01 20:45:31 +00001974Core
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001975----
Tim Petersa814db52001-05-14 07:05:58 +00001976
Tim Peters6d6c1a32001-08-02 04:15:00 +00001977- TENTATIVELY, a large amount of code implementing much of what's
1978 described in PEP 252 (Making Types Look More Like Classes) and PEP
1979 253 (Subtyping Built-in Types) was added. This will be released
1980 with Python 2.2a1. Documentation will be provided separately
1981 through http://www.python.org/2.2/. The purpose of releasing this
1982 with Python 2.2a1 is to test backwards compatibility. It is
1983 possible, though not likely, that a decision is made not to release
1984 this code as part of 2.2 final, if any serious backwards
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00001985 incompatibilities are found during alpha testing that cannot be
Tim Peters6d6c1a32001-08-02 04:15:00 +00001986 repaired.
1987
Guido van Rossum55a78992001-07-17 17:22:32 +00001988- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001989 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001990 more 'yield' statements. See PEP 255. Since this adds a new
1991 keyword to the language, this feature must be enabled by including a
1992 future statement: "from __future__ import generators" (see PEP 236).
1993 Generators will become a standard feature in a future release
1994 (probably 2.3). Without this future statement, 'yield' remains an
1995 ordinary identifier, but a warning is issued each time it is used.
1996 (These warnings currently don't conform to the warnings framework of
1997 PEP 230; we intend to fix this in 2.2a2.)
1998
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001999- The UTF-16 codec was modified to be more RFC compliant. It will now
2000 only remove BOM characters at the start of the string and then
2001 only if running in native mode (UTF-16-LE and -BE won't remove a
2002 leading BMO character).
2003
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00002004- Strings now have a new method .decode() to complement the already
2005 existing .encode() method. These two methods provide direct access
2006 to the corresponding decoders and encoders of the registered codecs.
2007
2008 To enhance the usability of the .encode() method, the special
2009 casing of Unicode object return values was dropped (Unicode objects
2010 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00002011
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00002012 Both methods will now return whatever the codec in charge of the
2013 requested encoding returns as object, e.g. Unicode codecs will
2014 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
2015 will return u"äöü"). This enables codec writer to create codecs
2016 for various simple to use conversions.
2017
2018 New codecs were added to demonstrate these new features (the .encode()
2019 and .decode() columns indicate the type of the returned objects):
2020
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002021 +---------+-----------+-----------+-----------------------------+
2022 |Name | .encode() | .decode() | Description |
2023 +=========+===========+===========+=============================+
2024 |uu | string | string | UU codec (e.g. for email) |
2025 +---------+-----------+-----------+-----------------------------+
2026 |base64 | string | string | base64 codec |
2027 +---------+-----------+-----------+-----------------------------+
2028 |quopri | string | string | quoted-printable codec |
2029 +---------+-----------+-----------+-----------------------------+
2030 |zlib | string | string | zlib compression |
2031 +---------+-----------+-----------+-----------------------------+
2032 |hex | string | string | 2-byte hex codec |
2033 +---------+-----------+-----------+-----------------------------+
2034 |rot-13 | string | Unicode | ROT-13 Unicode charmap codec|
2035 +---------+-----------+-----------+-----------------------------+
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00002036
Mark Hammond2a0af792001-05-14 03:09:36 +00002037- Some operating systems now support the concept of a default Unicode
2038 encoding for file system operations. Notably, Windows supports 'mbcs'
2039 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00002040 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00002041 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00002042
2043 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00002044 functions that return filenames (such as os.listdir()) to return Python
2045 string objects pre-encoded using the default file system encoding for
2046 the platform. As this encoding is likely to be different from Python's
2047 default encoding, converting this name to a Unicode object before passing
2048 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00002049 would attempt to use its default encoding (generally ASCII) rather than
2050 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00002051
Tim Petersa814db52001-05-14 07:05:58 +00002052 In general, this change simply removes surprises when working with
2053 Unicode and the file system, making these operations work as you expect,
2054 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00002055 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00002056
Tim Peters61dff2b2001-05-08 15:43:37 +00002057- Float (and complex) literals in source code were evaluated to full
2058 precision only when running from a .py file; the same code loaded from a
2059 .pyc (or .pyo) file could suffer numeric differences starting at about the
2060 12th significant decimal digit. For example, on a machine with IEEE-754
2061 floating arithmetic,
2062
2063 x = 9007199254740992.0
2064 print long(x)
2065
2066 printed 9007199254740992 if run directly from .py, but 9007199254740000
2067 if from a compiled (.pyc or .pyo) file. This was due to marshal using
2068 str(float) instead of repr(float) when building code objects. marshal
2069 now uses repr(float) instead, which should reproduce floats to full
2070 machine precision (assuming the platform C float<->string I/O conversion
2071 functions are of good quality).
2072
2073 This may cause floating-point results to change in some cases, and
2074 usually for the better, but may also cause numerically unstable
2075 algorithms to break.
2076
Tim Peters2f228e72001-05-13 00:19:31 +00002077- The implementation of dicts suffers fewer collisions, which has speed
2078 benefits. However, the order in which dict entries appear in dict.keys(),
2079 dict.values() and dict.items() may differ from previous releases for a
2080 given dict. Nothing is defined about this order, so no program should
2081 rely on it. Nevertheless, it's easy to write test cases that rely on the
2082 order by accident, typically because of printing the str() or repr() of a
2083 dict to an "expected results" file. See Lib/test/test_support.py's new
2084 sortdict(dict) function for a simple way to display a dict in sorted
2085 order.
2086
Tim Peters7a3bfc32001-06-12 01:22:22 +00002087- Many other small changes to dicts were made, resulting in faster
2088 operation along the most common code paths.
2089
Guido van Rossum10315822001-05-01 20:54:30 +00002090- Dictionary objects now support the "in" operator: "x in dict" means
2091 the same as dict.has_key(x).
2092
Barry Warsaw51acc8d2001-06-26 20:12:50 +00002093- The update() method of dictionaries now accepts generic mapping
2094 objects. Specifically the argument object must support the .keys()
2095 and __getitem__() methods. This allows you to say, for example,
2096 {}.update(UserDict())
2097
Guido van Rossum10315822001-05-01 20:54:30 +00002098- Iterators were added; this is a generalized way of providing values
2099 to a for loop. See PEP 234. There's a new built-in function iter()
2100 to return an iterator. There's a new protocol to get the next value
2101 from an iterator using the next() method (in Python) or the
2102 tp_iternext slot (in C). There's a new protocol to get iterators
2103 using the __iter__() method (in Python) or the tp_iter slot (in C).
2104 Iterating (i.e. a for loop) over a dictionary generates its keys.
2105 Iterating over a file generates its lines.
2106
Tim Petersf553f892001-05-01 20:45:31 +00002107- The following functions were generalized to work nicely with iterator
Skip Montanaroa2a07bc2002-09-30 15:23:01 +00002108 arguments::
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002109
Tim Peterse63415e2001-05-08 04:38:29 +00002110 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00002111 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
2112 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00002113 join() method of strings
2114 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00002115 'x in y' and 'x not in y' (PySequence_Contains() in C API)
2116 operator.countOf() (PySequence_Count() in C API)
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002117 right-hand side of assignment statements with multiple targets, such as ::
Tim Petersd6d010b2001-06-21 02:49:55 +00002118 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00002119
Tim Petersd85e1022001-05-11 21:51:48 +00002120- Accessing module attributes is significantly faster (for example,
2121 random.random or os.path or yourPythonModule.yourAttribute).
2122
Tim Peterse63415e2001-05-08 04:38:29 +00002123- Comparing dictionary objects via == and != is faster, and now works even
2124 if the keys and values don't support comparisons other than ==.
2125
Tim Peters95bf9392001-05-10 08:32:44 +00002126- Comparing dictionaries in ways other than == and != is slower: there were
2127 insecurities in the dict comparison implementation that could cause Python
2128 to crash if the element comparison routines for the dict keys and/or
2129 values mutated the dicts. Making the code bulletproof slowed it down.
2130
Tim Peterseb28ef22001-06-02 05:27:19 +00002131- Collisions in dicts are resolved via a new approach, which can help
2132 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00002133 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00002134 faster now. Thanks to Christian Tismer for pointing out the cause and
2135 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00002136
Tim Peters52e155e2001-06-16 05:42:57 +00002137- repr() is much faster for large containers (dict, list, tuple).
2138
2139
Tim Petersa814db52001-05-14 07:05:58 +00002140Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002141-------
Tim Petersa814db52001-05-14 07:05:58 +00002142
Fred Drake960fdf92001-07-20 18:38:26 +00002143- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002144 were added to the string module. These a locale-independent
Fred Drake960fdf92001-07-20 18:38:26 +00002145 constants, unlike letters, lowercase, and uppercase. These are now
2146 use in appropriate locations in the standard library.
2147
Martin v. Löwisf0473d52001-07-18 16:17:16 +00002148- The flags used in dlopen calls can now be configured using
2149 sys.setdlopenflags and queried using sys.getdlopenflags.
2150
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00002151- Fredrik Lundh's xmlrpclib is now a standard library module. This
2152 provides full client-side XML-RPC support. In addition,
2153 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
2154 one asyncore-based). Thanks to Eric Raymond for the documentation.
2155
Guido van Rossum643d3912001-07-05 14:46:25 +00002156- The xrange() object is simplified: it no longer supports slicing,
2157 repetition, comparisons, efficient 'in' checking, the tolist()
2158 method, or the start, stop and step attributes. See PEP 260.
2159
Martin v. Löwisebf94db2001-06-06 06:25:40 +00002160- A new function fnmatch.filter to filter lists of file names was added.
2161
Barry Warsawffd674d2001-05-22 16:00:10 +00002162- calendar.py uses month and day names based on the current locale.
2163
Guido van Rossum2e0a6542001-05-15 02:14:44 +00002164- strop is now *really* obsolete (this was announced before with 1.6),
2165 and issues DeprecationWarning when used (except for the four items
2166 that are still imported into string.py).
2167
Tim Petersa814db52001-05-14 07:05:58 +00002168- Cookie.py now sorts key+value pairs by key in output strings.
2169
2170- pprint.isrecursive(object) didn't correctly identify recursive objects.
2171 Now it does.
2172
Tim Peters95b3f782001-05-14 18:39:41 +00002173- pprint functions now much faster for large containers (tuple, list, dict).
2174
Tim Peters7b9542a2001-06-10 23:40:19 +00002175- New 'q' and 'Q' format codes in the struct module, corresponding to C
2176 types "long long" and "unsigned long long" (on Windows, __int64). In
2177 native mode, these can be used only when the platform C compiler supports
2178 these types (when HAVE_LONG_LONG is #define'd by the Python config
2179 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00002180 In standard mode, 'q' and 'Q' are supported on all platforms, and are
2181 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00002182
Guido van Rossum83213cc2001-06-12 16:48:52 +00002183- The site module installs a new built-in function 'help' that invokes
2184 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
2185 it displays a message reminding the user to use 'help()' or
2186 'help(object)'.
2187
Tim Petersa814db52001-05-14 07:05:58 +00002188Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002189-----
Tim Petersa814db52001-05-14 07:05:58 +00002190
2191- New test_mutants.py runs dict comparisons where the key and value
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002192 comparison operators mutate the dicts randomly during comparison. This
Tim Petersa814db52001-05-14 07:05:58 +00002193 rapidly causes Python to crash under earlier releases (not for the faint
2194 of heart: it can also cause Win9x to freeze or reboot!).
2195
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002196- New test_pprint.py verifies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00002197 pprint.isreadable() return sensible results. Also verifies that simple
2198 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00002199
Tim Peters4324aa32001-05-28 22:30:08 +00002200C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002201-----
Tim Peters4324aa32001-05-28 22:30:08 +00002202
2203- Removed the unused last_is_sticky argument from the internal
2204 _PyTuple_Resize(). If this affects you, you were cheating.
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002205
2206----
2207
2208**(For information about older versions, consult the HISTORY file.)**