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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
Walter Dörwald3aeb6322002-09-02 13:14:32 +000069- Codec error handling callbacks (PEP 293) are implemented.
70 Error handling in unicode.encode or str.decode can now be customized.
71
Guido van Rossum45ec02a2002-08-19 21:43:18 +000072- A subtle change to the semantics of the built-in function intern():
73 interned strings are no longer immortal. You must keep a reference
74 to the return value intern() around to get the benefit.
75
Guido van Rossumf808b892002-08-16 03:38:10 +000076- Use of 'None' as a variable, argument or attribute name now
77 issues a SyntaxWarning. In the future, None may become a keyword.
78
Michael W. Hudsondd32a912002-08-15 14:59:02 +000079- SET_LINENO is gone. co_lnotab is now consulted to determine when to
80 call the trace function. C code that accessed f_lineno should call
81 PyCode_Addr2Line instead (f_lineno is still there, but not kept up
82 to date).
83
Guido van Rossum9be89462002-08-14 16:11:30 +000084- There's a new warning category, FutureWarning. This is used to warn
85 about a number of situations where the value or sign of an integer
86 result will change in Python 2.4 as a result of PEP 237 (integer
87 unification). The warnings implement stage B0 mentioned in that
88 PEP. The warnings are about the following situations:
89
90 - Octal and hex literals without 'L' prefix in the inclusive range
91 [0x80000000..0xffffffff]; these are currently negative ints, but
92 in Python 2.4 they will be positive longs with the same bit
93 pattern.
94
95 - Left shifts on integer values that cause the outcome to lose
96 bits or have a different sign than the left operand. To be
97 precise: x<<n where this currently doesn't yield the same value
98 as long(x)<<n; in Python 2.4, the outcome will be long(x)<<n.
99
100 - Conversions from ints to string that show negative values as
101 unsigned ints in the inclusive range [0x80000000..0xffffffff];
102 this affects the functions hex() and oct(), and the string
103 formatting codes %u, %o, %x, and %X. In Python 2.4, these will
104 show signed values (e.g. hex(-1) currently returns "0xffffffff";
105 in Python 2.4 it will return "-0x1").
106
Skip Montanaro979c74b2002-09-03 21:25:14 +0000107 - The bits manipulated under the cover by sys.setcheckinterval() have
108 been changed. Both the check interval and the ticker used to be
109 per-thread values. They are now just a pair of global variables. In
110 addition, the default check interval was boosted from 10 to 100
Neal Norwitz7165af22002-09-05 21:42:24 +0000111 bytecode instructions. This may have some effect on systems that
112 relied on the old default value. In particular, in multi-threaded
113 applications which try to be highly responsive, response time will
114 increase by some (perhaps imperceptible) amount.
Skip Montanaro979c74b2002-09-03 21:25:14 +0000115
Tim Petersd64c1de2002-08-12 17:36:03 +0000116- When multiplying very large integers, a version of the so-called
117 Karatsuba algorithm is now used. This is most effective if the
118 inputs have roughly the same size. If they both have about N digits,
119 Karatsuba multiplication has O(N**1.58) runtime (the exponent is
120 log_base_2(3)) instead of the previous O(N**2). Measured results may
Tim Peters012c0a32002-08-16 03:40:07 +0000121 be better or worse than that, depending on platform quirks. Besides
122 the O() improvement in raw instruction count, the Karatsuba algorithm
123 appears to have much better cache behavior on extremely large integers
124 (starting in the ballpark of a million bits). Note that this is a
125 simple implementation, and there's no intent here to compete with,
126 e.g., GMP. It gives a very nice speedup when it applies, but a package
127 devoted to fast large-integer arithmetic should run circles around it.
Tim Peters5af4e6c2002-08-12 02:31:19 +0000128
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +0000129- u'%c' will now raise a ValueError in case the argument is an
130 integer outside the valid range of Unicode code point ordinals.
131
Guido van Rossumdeb09362002-08-09 17:16:30 +0000132- The tempfile module has been overhauled for enhanced security. The
133 mktemp() function is now deprecated; new, safe replacements are
134 mkstemp() (for files) and mkdtemp() (for directories), and the
135 higher-level functions NamedTemporaryFile() and TemporaryFile().
136 Use of some global variables in this module is also deprecated; the
137 new functions have keyword arguments to provide the same
138 functionality. All Lib, Tools and Demo modules that used the unsafe
139 interfaces have been updated to use the safe replacements. Thanks
140 to Zack Weinberg!
141
Guido van Rossumd81a9832002-08-09 15:57:34 +0000142- When x is an object whose class implements __mul__ and __rmul__,
143 1.0*x would correctly invoke __rmul__, but 1*x would erroneously
144 invoke __mul__. This was due to the sequence-repeat code in the int
145 type. This has been fixed now.
146
Barry Warsawd79f6832002-08-06 17:01:51 +0000147- Previously, "str1 in str2" required str1 to be a string of length 1.
148 This restriction has been relaxed to allow str1 to be a string of
149 any length. Thus "'el' in 'hello world'" returns True now.
150
Guido van Rossumb57089c2002-08-06 16:20:26 +0000151- File objects are now their own iterators. For a file f, iter(f) now
152 returns f (unless f is closed), and f.next() is similar to
153 f.readline() when EOF is not reached; however, f.next() uses a
154 readahead buffer that messes up the file position, so mixing
155 f.next() and f.readline() (or other methods) doesn't work right.
156 Calling f.seek() drops the readahead buffer, but other operations
157 don't. It so happens that this gives a nice additional speed boost
158 to "for line in file:"; the xreadlines method and corresponding
Guido van Rossumbffb2ef2002-08-09 17:17:07 +0000159 module are now obsolete. Thanks to Oren Tirosh!
Guido van Rossumb57089c2002-08-06 16:20:26 +0000160
Guido van Rossumde392d32002-08-05 14:17:20 +0000161- Encoding declarations (PEP 263, phase 1) have been implemented. A
162 comment of the form "# -*- coding: <encodingname> -*-" in the first
163 or second line of a Python source file indicates the encoding.
Martin v. Löwis00f1e3f2002-08-04 17:29:52 +0000164
Tim Petersf47630f2002-08-01 02:34:51 +0000165- list.sort() has a new implementation. While cross-platform results
166 may vary, and in data-dependent ways, this is much faster on many
167 kinds of partially ordered lists than the previous implementation,
168 and reported to be just as fast on randomly ordered lists on
169 several major platforms. This sort is also stable (if A==B and A
170 precedes B in the list at the start, A precedes B after the sort too),
171 although the language definition does not guarantee stability. A
172 potential drawback is that list.sort() may require temp space of
Skip Montanaroa2a07bc2002-09-30 15:23:01 +0000173 len(list)*2 bytes (``*4`` on a 64-bit machine). It's therefore possible
Tim Petersf47630f2002-08-01 02:34:51 +0000174 for list.sort() to raise MemoryError now, even if a comparison function
175 does not. See <http://www.python.org/sf/587076> for full details.
176
Guido van Rossum2d5389c2002-07-23 03:44:35 +0000177- All standard iterators now ensure that, once StopIteration has been
178 raised, all future calls to next() on the same iterator will also
179 raise StopIteration. There used to be various counterexamples to
180 this behavior, which could caused confusion or subtle program
181 breakage, without any benefits. (Note that this is still an
182 iterator's responsibility; the iterator framework does not enforce
183 this.)
184
Mark Hammondc0e35152002-07-16 01:32:30 +0000185- Ctrl+C handling on Windows has been made more consistent with
186 other platforms. KeyboardInterrupt can now reliably be caught,
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +0000187 and Ctrl+C at an interactive prompt no longer terminates the
Mark Hammondc0e35152002-07-16 01:32:30 +0000188 process under NT/2k/XP (it never did under Win9x). Ctrl+C will
Tim Peters5af4e6c2002-08-12 02:31:19 +0000189 interrupt time.sleep() in the main thread, and any child processes
190 created via the popen family (on win2k; we can't make win9x work
Mark Hammond8f3afc72002-08-10 06:26:31 +0000191 reliably) are also interrupted (as generally happens on for Linux/Unix.)
192 [SF bugs 231273, 439992 and 581232]
Mark Hammondc0e35152002-07-16 01:32:30 +0000193
Raymond Hettinger5a04aec2002-06-25 00:25:30 +0000194- Slices and repetitions of buffer objects now consistently return
195 a string. Formerly, strings would be returned most of the time,
196 but a buffer object would be returned when the repetition count
197 was one or when the slice range was all inclusive.
198
Walter Dörwald3430d702002-06-17 10:43:59 +0000199- Unicode objects in sys.path are no longer ignored but treated
200 as directory names.
201
Neal Norwitz1f68fc72002-06-14 00:50:42 +0000202- Fixed string.startswith and string.endswith builtin methods
203 so they accept negative indices. [SF bug 493951]
204
Guido van Rossumc5fe5eb2002-06-12 03:45:21 +0000205- Fixed a bug with a continue inside a try block and a yield in the
206 finally clause. [SF bug 567538]
207
Michael W. Hudson5efaf7e2002-06-11 10:55:12 +0000208- Most builtin sequences now support "extended slices", i.e. slices
Guido van Rossum2e82e712002-06-13 11:41:07 +0000209 with a third "stride" parameter. For example, "hello world"[::-1]
210 gives "dlrow olleh".
Michael W. Hudson5efaf7e2002-06-11 10:55:12 +0000211
Neal Norwitzd68f5172002-05-29 15:54:55 +0000212- A new warning PendingDeprecationWarning was added to provide
213 direction on features which are in the process of being deprecated.
214 The warning will not be printed by default. To see the pending
215 deprecations, use -Walways::PendingDeprecationWarning::
216 as a command line option or warnings.filterwarnings() in code.
217
Fred Draked0ba6362002-05-02 21:28:26 +0000218- Deprecated features of xrange objects have been removed as
219 promised. The start, stop, and step attributes and the tolist()
220 method no longer exist. xrange repetition and slicing have been
221 removed.
222
Guido van Rossum7dab2422002-04-26 19:40:56 +0000223- New builtin function enumerate(x), from PEP 279. Example:
224 enumerate("abc") is an iterator returning (0,"a"), (1,"b"), (2,"c").
225 The argument can be an arbitrary iterable object.
226
Neil Schemenauer89e3ee02002-04-26 01:58:53 +0000227- The assert statement no longer tests __debug__ at runtime. This means
228 that assert statements cannot be disabled by assigning a false value
229 to __debug__.
230
Walter Dörwald068325e2002-04-15 13:36:47 +0000231- A method zfill() was added to str and unicode, that fills a numeric
232 string to the left with zeros. For example,
233 "+123".zfill(6) -> "+00123".
234
Guido van Rossum862fe3c2002-04-15 12:36:47 +0000235- Complex numbers supported divmod() and the // and % operators, but
236 these make no sense. Since this was documented, they're being
237 deprecated now.
238
Guido van Rossum26dd8302002-04-26 20:11:29 +0000239- String and unicode methods lstrip(), rstrip() and strip() now take
240 an optional argument that specifies the characters to strip. For
241 example, "Foo!!!?!?!?".rstrip("?!") -> "Foo".
Guido van Rossum49042042002-04-13 00:59:05 +0000242
Guido van Rossumc69343b2002-04-12 19:22:48 +0000243- Added a new dict method pop(key). This removes and returns the
244 value corresponding to key. [SF patch #539949]
245
Guido van Rossum47834462002-04-04 15:21:33 +0000246- A new built-in type, bool, has been added, as well as built-in
247 names for its two values, True and False. Comparisons and sundry
248 other operations that return a truth value have been changed to
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000249 return a bool instead. Read PEP 285 for an explanation of why this
Guido van Rossum47834462002-04-04 15:21:33 +0000250 is backward compatible.
251
Guido van Rossum95b62a62002-03-29 01:07:24 +0000252- Fixed two bugs reported as SF #535905: under certain conditions,
253 deallocating a deeply nested structure could cause a segfault in the
254 garbage collector, due to interaction with the "trashcan" code;
255 access to the current frame during destruction of a local variable
256 could access a pointer to freed memory.
257
Guido van Rossumfe0ca4a2002-06-18 21:20:13 +0000258- The optional object allocator ("pymalloc") has been enabled by
259 default. The recommended practice for memory allocation and
260 deallocation has been streamlined. A header file is included,
261 Misc/pymemcompat.h, which can be bundled with 3rd party extensions
262 and lets them use the same API with Python versions from 1.5.2
263 onwards.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000264
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +0000265- PyErr_Display will provide file and line information for all exceptions
266 that have an attribute print_file_and_line, not just SyntaxErrors.
267
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000268- The UTF-8 codec will now encode and decode Unicode surrogates
269 correctly and without raising exceptions for unpaired ones.
270
Guido van Rossumadd88062002-08-15 14:01:14 +0000271- Universal newlines (PEP 278) is implemented. Briefly, using 'U'
272 instead of 'r' when opening a text file for reading changes the line
273 ending convention so that any of '\r', '\r\n', and '\n' is
274 recognized (even mixed in one file); all three are converted to
275 '\n', the standard Python line end character.
276
Neal Norwitz649b7592002-01-01 19:07:13 +0000277- file.xreadlines() now raises a ValueError if the file is closed:
278 Previously, an xreadlines object was returned which would raise
279 a ValueError when the xreadlines.next() method was called.
280
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000281- sys.exit() inadvertently allowed more than one argument.
Neal Norwitz0c766a02002-03-27 13:03:09 +0000282 An exception will now be raised if more than one argument is used.
283
Tim Petersaf8446f2001-12-21 21:36:50 +0000284Extension modules
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000285-----------------
Tim Petersaf8446f2001-12-21 21:36:50 +0000286
Guido van Rossumba602972002-10-01 18:18:58 +0000287- The _tkinter module (and hence Tkinter) has dropped support for
288 Tcl/Tk 8.0 and 8.1. Only Tcl/Tk versions 8.2, 8.3 and 8.4 are
289 supported.
290
Martin v. Löwis658009a2002-09-16 17:26:24 +0000291- cPickle.BadPickleGet is now a class.
292
Martin v. Löwisa32c9942002-09-09 16:17:47 +0000293- The time stamps in os.stat_result are floating point numbers now.
Martin v. Löwis94717ed2002-09-09 14:24:16 +0000294
Neal Norwitzb5673922002-09-05 21:48:07 +0000295- If the size passed to mmap.mmap() is larger than the length of the
296 file on non-Windows platforms, a ValueError is raised. [SF bug 585792]
297
Guido van Rossumb57089c2002-08-06 16:20:26 +0000298- The xreadlines module is slated for obsolescence.
299
Guido van Rossum79f0a102002-07-23 03:32:08 +0000300- The strptime function in the time module is now always available (a
301 Python implementation is used when the C library doesn't define it).
302
Guido van Rossum9562bcf2002-06-14 21:31:18 +0000303- The 'new' module is no longer an extension, but a Python module that
304 only exists for backwards compatibility. Its contents are no longer
305 functions but callable type objects.
306
Tim Peters81b92512002-04-29 01:37:32 +0000307- The bsddb.*open functions can now take 'None' as a filename.
Anthony Baxter83888952002-04-23 02:11:05 +0000308 This will create a temporary in-memory bsddb that won't be
Tim Peters81b92512002-04-29 01:37:32 +0000309 written to disk.
Anthony Baxter83888952002-04-23 02:11:05 +0000310
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000311- posix.lchown, posix.killpg, posix.mknod, and posix.getpgid have been
312 added where available.
Martin v. Löwis06a83e92002-04-14 10:19:44 +0000313
Martin v. Löwis2e64c342002-03-27 18:49:02 +0000314- The locale module now exposes the C library's gettext interface.
315
Tim Petersfbf74f22002-03-14 19:06:01 +0000316- A security hole ("double free") was found in zlib-1.1.3, a popular
317 third party compression library used by some Python modules. The
318 hole was quickly plugged in zlib-1.1.4, and the Windows build of
319 Python now ships with zlib-1.1.4.
320
Martin v. Löwis688357e2002-04-08 21:28:20 +0000321- pwd, grp, and resource return enhanced tuples now, with symbolic
322 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +0000323
Martin v. Löwis99866332002-03-01 10:27:01 +0000324- array.array is now a type object. A new format character
325 'u' indicates Py_UNICODE arrays. For those, .tounicode and
326 .fromunicode methods are available. Arrays now support __iadd__
327 and __imul__.
328
Neal Norwitze790eae2002-01-01 21:14:12 +0000329- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +0000330 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
331 is called.
332
Michael W. Hudson34f20ea2002-05-27 15:08:24 +0000333- signal.sigpending, signal.sigprocmask and signal.sigsuspend have
334 been added where available.
335
Skip Montanaro8e790e72002-09-03 13:25:17 +0000336- The sys module acquired a new attribute, api_version, which evaluates
337 to the value of the PYTHON_API_VERSION macro with which the
338 interpreter was compiled.
339
Tim Petersaf8446f2001-12-21 21:36:50 +0000340Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000341-------
Tim Petersaf8446f2001-12-21 21:36:50 +0000342
Walter Dörwald5ccaf8f2002-09-06 16:15:58 +0000343- mimetypes has two new functions: guess_all_extensions() which
344 returns a list of all known extensions for a mime type, and
345 add_type() which adds one mapping between a mime type and
346 an extension to the database.
347
Guido van Rossumd8ab35c2002-08-19 16:25:46 +0000348- New module: sets, defines the class Set that implements a mutable
349 set type using the keys of a dict to represent the set. There's
350 also a class ImmutableSet which is useful when you need sets of sets
351 or when you need to use sets as dict keys, and a class BaseSet which
352 is the base class of the two. (This is not documented yet, but
353 help(sets) gives a wealth of information.)
354
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +0000355- Added operator.pow(a,b) which is equivalent to a**b.
356
Tim Peters012c0a32002-08-16 03:40:07 +0000357- random.randrange(-sys.maxint-1, sys.maxint) no longer raises
358 OverflowError. That is, it now accepts any combination of 'start'
359 and 'stop' arguments so long as each is in the range of Python's
360 bounded integers.
361
Guido van Rossum4a57c332002-08-02 18:05:20 +0000362- New "algorithms" module: heapq, implements a heap queue. Thanks to
363 Kevin O'Connor for the code and François Pinard for an entertaining
364 write-up explaining the theory and practical uses of heaps.
365
Marc-André Lemburg58e2ff22002-07-12 14:40:04 +0000366- New encoding for the Palm OS character set: palmos.
367
Tim Peters943382c2002-07-07 03:59:34 +0000368- binascii.crc32() and the zipfile module had problems on some 64-bit
369 platforms. These have been fixed. On a platform with 8-byte C longs,
370 crc32() now returns a signed-extended 4-byte result, so that its value
371 as a Python int is equal to the value computed a 32-bit platform.
372
Martin v. Löwis7d650ca2002-06-30 15:05:00 +0000373- xml.dom.minidom.toxml and toprettyxml now take an optional encoding
374 argument.
375
Guido van Rossum9f7549b2002-06-10 21:39:42 +0000376- Some fixes in the copy module: when an object is copied through its
377 __reduce__ method, there was no check for a __setstate__ method on
378 the result [SF patch 565085]; deepcopy should treat instances of
379 custom metaclasses the same way it treats instances of type 'type'
380 [SF patch 560794].
381
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000382- Sockets now support timeout mode. After s.settimeout(T), where T is
383 a float expressing seconds, subsequent operations raise an exception
384 if they cannot be completed within T seconds. To disable timeout
Guido van Rossum79f0a102002-07-23 03:32:08 +0000385 mode, use s.settimeout(None). There's also a module function,
386 socket.setdefaulttimeout(T), which sets the default for all sockets
387 created henceforth.
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000388
389- getopt.gnu_getopt was added. This supports GNU-style option
390 processing, where options can be mixed with non-option arguments.
Martin v. Löwis446a25f2002-06-06 10:58:36 +0000391
Michael W. Hudsonb0dc1a32002-06-04 18:27:35 +0000392- Stop using strings for exceptions. String objects used for
393 exceptions are now classes deriving from Exception. The objects
394 changed were: Tkinter.TclError, bdb.BdbQuit, macpath.norm_error,
395 tabnanny.NannyNag, and xdrlib.Error.
Neal Norwitzb5b5a262002-06-04 17:14:07 +0000396
Walter Dörwald474458d2002-06-04 15:16:29 +0000397- Constants BOM_UTF8, BOM_UTF16, BOM_UTF16_LE, BOM_UTF16_BE,
398 BOM_UTF32, BOM_UTF32_LE and BOM_UTF32_BE that represent the Byte
399 Order Mark in UTF-8, UTF-16 and UTF-32 encodings for little and
400 big endian systems were added to the codecs module. The old names
401 BOM32_* and BOM64_* were off by a factor of 2.
402
Guido van Rossumf9257822002-06-18 20:43:18 +0000403- Added conversion functions math.degrees() and math.radians().
Raymond Hettinger87f59ee2002-05-13 04:17:32 +0000404
Raymond Hettinger9b1df1d2002-05-12 06:07:21 +0000405- ftplib.retrlines() now tests for callback is None rather than testing
406 for False. Was causing an error when given a callback object which
407 was callable but also returned len() as zero. The change may
408 create new breakage if the caller relied on the undocumented behavior
409 and called with callback set to [] or some other False value not
410 identical to None.
411
Tim Peters46c04e12002-05-05 20:40:00 +0000412- random.gauss() uses a piece of hidden state used by nothing else,
413 and the .seed() and .whseed() methods failed to reset it. In other
414 words, setting the seed didn't completely determine the sequence of
415 results produced by random.gauss(). It does now. Programs repeatedly
416 mixing calls to a seed method with calls to gauss() may see different
417 results now.
418
Fred Drake7f781c92002-05-01 20:33:53 +0000419- The pickle.Pickler class grew a clear_memo() method to mimic that
420 provided by cPickle.Pickler.
421
Tim Peters81b92512002-04-29 01:37:32 +0000422- difflib's SequenceMatcher class now does a dynamic analysis of
423 which elements are so frequent as to constitute noise. For
424 comparing files as sequences of lines, this generally works better
425 than the IS_LINE_JUNK function, and function ndiff's linejunk
426 argument defaults to None now as a result. A happy benefit is
427 that SequenceMatcher may run much faster now when applied
428 to large files with many duplicate lines (for example, C program
429 text with lots of repeated "}" and "return NULL;" lines).
430
Guido van Rossum256705b2002-04-23 13:29:43 +0000431- New Text.dump() method in Tkinter module.
432
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000433- New distutils commands for building packagers were added to
434 support pkgtool on Solaris and swinstall on HP-UX.
435
436- distutils now has a new abstract binary packager base class
437 command/bdist_packager, which simplifies writing packagers.
438 This will hopefully provide the missing bits to encourage
439 people to submit more packagers, e.g. for Debian, FreeBSD
440 and other systems.
441
Guido van Rossumf9257822002-06-18 20:43:18 +0000442- The UTF-16, -LE and -BE stream readers now raise a
443 NotImplementedError for all calls to .readline(). Previously, they
444 used to just produce garbage or fail with an encoding error --
445 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 +0000446 work well with these.
447
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000448- compileall now supports quiet operation.
449
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000450- The BaseHTTPServer now implements optional HTTP/1.1 persistent
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000451 connections.
452
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000453- socket module: the SSL support was broken out of the main
454 _socket module C helper and placed into a new _ssl helper
455 which now gets imported by socket.py if available and working.
456
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000457- encodings package: added aliases for all supported IANA character
458 sets
459
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000460- ftplib: to safeguard the user's privacy, anonymous login will use
461 "anonymous@" as default password, rather than the real user and host
462 name.
463
Fred Drake36736122002-01-10 13:50:31 +0000464- webbrowser: tightened up the command passed to os.system() so that
465 arbitrary shell code can't be executed because a bogus URL was
466 passed in.
467
Tim Peters11bd9942002-02-01 00:52:29 +0000468- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000469 gettext.find an optional all argument. Translations will now fallback
470 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000471
Martin v. Löwis9668b932002-01-12 11:27:42 +0000472- distutils bdist commands now offer a --skip-build option.
473
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000474- warnings.warn now accepts a Warning instance as first argument.
475
Fred Drakefed7e852002-04-04 19:36:15 +0000476- The xml.sax.expatreader.ExpatParser class will no longer create
477 circular references by using itself as the locator that gets passed
478 to the content handler implementation. [SF bug #535474]
479
Barry Warsaw47f3e2c2002-05-20 00:14:24 +0000480- The email.Parser.Parser class now properly parses strings regardless
481 of their line endings, which can be any of \r, \n, or \r\n (CR, LF,
482 or CRLF). Also, the Header class's constructor default arguments
483 has changed slightly so that an explicit maxlinelen value is always
484 honored.
485
Tim Petersaf8446f2001-12-21 21:36:50 +0000486Tools/Demos
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000487-----------
Tim Petersaf8446f2001-12-21 21:36:50 +0000488
Guido van Rossum923e4ef2002-09-17 20:58:59 +0000489- The SGI demos (Demo/sgi) have been removed. Nobody thought they
490 were interesting any more. (The SGI library modules and extensions
491 are still there; it is believed that at least some of these are
492 still used and useful.)
493
Fred Drake40813b12002-08-05 15:24:19 +0000494- IDLE supports the new encoding declarations (PEP 263); it can also
495 deal with legacy 8-bit files if they use the locale's encoding. It
496 allows non-ASCII strings in the interactive shell and executes them
497 in the locale's encoding.
Martin v. Löwis98ce7b72002-08-05 15:11:26 +0000498
Marc-André Lemburg46260092002-04-04 16:17:11 +0000499- freeze.py now produces binaries which can import shared modules,
500 unlike before when this failed due to missing symbol exports in
501 the generated binary.
502
Tim Petersaf8446f2001-12-21 21:36:50 +0000503Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000504-----
Tim Petersaf8446f2001-12-21 21:36:50 +0000505
Guido van Rossum6b3db552002-09-25 15:02:44 +0000506- The fpectl module is not built by default; it's dangerous or useless
507 except in the hands of experts.
508
Tim Petersf47630f2002-08-01 02:34:51 +0000509- The public Python C API will generally be declared using PyAPI_FUNC
Guido van Rossum6b3db552002-09-25 15:02:44 +0000510 and PyAPI_DATA macros, while Python extension module init functions
511 will be declared with PyMODINIT_FUNC. DL_EXPORT/DL_IMPORT macros
512 are deprecated.
Neal Norwitz1389f3e2002-07-22 13:21:10 +0000513
Tim Petersc6a3ff62002-07-08 22:11:52 +0000514- A bug was fixed that could cause COUNT_ALLOCS builds to segfault, or
515 get into infinite loops, when a new-style class got garbage-collected.
516 Unfortunately, to avoid this, the way COUNT_ALLOCS works requires
517 that new-style classes be immortal in COUNT_ALLOCS builds. Note that
518 COUNT_ALLOCS is not enabled by default, in either release or debug
519 builds, and that new-style classes are immortal only in COUNT_ALLOCS
520 builds.
521
Tim Peters943382c2002-07-07 03:59:34 +0000522- Compiling out the cyclic garbage collector is no longer an option.
523 The old symbol WITH_CYCLE_GC is now ignored, and Python.h arranges
524 that it's always defined (for the benefit of any extension modules
525 that may be conditionalizing on it). A bonus is that any extension
526 type participating in cyclic gc can choose to participate in the
527 Py_TRASHCAN mechanism now too; in the absence of cyclic gc, this used
528 to require editing the core to teach the trashcan mechanism about the
529 new type.
530
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000531- According to Annex F of the current C standard,
Tim Peters1de41bf2002-07-03 03:31:20 +0000532
533 The Standard C macro HUGE_VAL and its float and long double analogs,
534 HUGE_VALF and HUGE_VALL, expand to expressions whose values are
535 positive infinities.
536
537 Python only uses the double HUGE_VAL, and only to #define its own symbol
538 Py_HUGE_VAL. Some platforms have incorrect definitions for HUGE_VAL.
539 pyport.h used to try to worm around that, but the workarounds triggered
540 other bugs on other platforms, so we gave up. If your platform defines
541 HUGE_VAL incorrectly, you'll need to #define Py_HUGE_VAL to something
542 that works on your platform. The only instance of this I'm sure about
543 is on an unknown subset of Cray systems, described here:
544
545 http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm
546
547 Presumably 2.3a1 breaks such systems. If anyone uses such a system, help!
548
Martin v. Löwisa3fb4f72002-06-09 13:33:54 +0000549- The configure option --without-doc-strings can be used to remove the
550 doc strings from the builtin functions and modules; this reduces the
551 size of the executable.
552
Guido van Rossumadd88062002-08-15 14:01:14 +0000553- The universal newlines option (PEP 278) is on by default. On Unix
554 it can be disabled by passing --without-universal-newlines to the
555 configure script. On other platforms, remove
556 WITH_UNIVERSAL_NEWLINES from pyconfig.h.
Tim Peters639295f2002-04-21 07:30:30 +0000557
Martin v. Löwis1142de32002-03-29 16:28:31 +0000558- On Unix, a shared libpython2.3.so can be created with --enable-shared.
559
Tim Peters8deda702002-03-30 10:06:07 +0000560- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
561 preprocessor symbols were eliminated. The internal decisions they
562 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000563
Fred Drake7d28b732002-05-02 21:17:00 +0000564- The tools used to build the documentation now work under Cygwin as
565 well as Unix.
566
Skip Montanaro57454e52002-06-14 20:30:31 +0000567- The bsddb and dbm module builds have been changed to try and avoid version
568 skew problems and disable linkage with Berkeley DB 1.85 unless the
569 installer knows what s/he's doing. See the section on building these
570 modules in the README file for details.
571
Tim Petersaf8446f2001-12-21 21:36:50 +0000572C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000573-----
Tim Petersaf8446f2001-12-21 21:36:50 +0000574
Guido van Rossum45ec02a2002-08-19 21:43:18 +0000575- The string object's layout has changed: the pointer member
576 ob_sinterned has been replaced by an int member ob_sstate. On some
577 platforms (e.g. most 64-bit systems) this may change the offset of
578 the ob_sval member, so as a precaution the API_VERSION has been
579 incremented. The apparently unused feature of "indirect interned
580 strings", supported by the ob_sinterned member, is gone. Interned
581 strings are now usually mortal; theres a new API,
582 PyString_InternImmortal() that creates immortal interned strings.
583 (The ob_sstate member can only take three values; however, while
584 making it a char saves a few bytes per string object on average, in
585 it also slowed things down a bit because ob_sval was no longer
586 aligned.)
587
Guido van Rossumfdb86482002-08-14 21:20:32 +0000588- The Py_InitModule*() functions now accept NULL for the 'methods'
589 argument. Modules without global functions are becoming more common
590 now that factories can be types rather than functions.
591
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +0000592- New C API PyUnicode_FromOrdinal() which exposes unichr() at C
593 level.
594
Thomas Heller085358a2002-07-29 14:27:41 +0000595- New functions PyErr_SetExcFromWindowsErr() and
596 PyErr_SetExcFromWindowsErrWithFilename(). Similar to
597 PyErr_SetFromWindowsErrWithFilename() and
598 PyErr_SetFromWindowsErr(), but they allow to specify
599 the exception type to raise. Available on Windows.
600
Tim Peters7c321a82002-07-09 02:57:01 +0000601- Py_FatalError() is now declared as taking a const char* argument. It
602 was previously declared without const. This should not affect working
603 code.
604
Martin v. Löwis01f94bd2002-05-08 08:44:21 +0000605- Added new macro PySequence_ITEM(o, i) that directly calls
606 sq_item without rechecking that o is a sequence and without
607 adjusting for negative indices.
608
Fred Draked0ba6362002-05-02 21:28:26 +0000609- PyRange_New() now raises ValueError if the fourth argument is not 1.
610 This is part of the removal of deprecated features of the xrange
611 object.
612
Guido van Rossum517c7d42002-04-26 02:49:14 +0000613- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
614 coercion if both arguments have the same type but this type has the
615 CHECKTYPES flag set. This is to better support proxies.
616
Skip Montanaroa2a07bc2002-09-30 15:23:01 +0000617- The type of tp_free has been changed from "``void (*)(PyObject *)``" to
618 "``void (*)(void *)``".
Neil Schemenauer9344b142002-04-12 23:00:08 +0000619
620- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
621
Guido van Rossum0986d822002-04-08 01:38:42 +0000622- A type can now inherit its metatype from its base type. Previously,
623 when PyType_Ready() was called, if ob_type was found to be NULL, it
624 was always set to &PyType_Type; now it is set to base->ob_type,
625 where base is tp_base, defaulting to &PyObject_Type.
626
627- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
628
Neil Schemenauerc9abc1d2002-05-08 14:14:41 +0000629- The PyCore_* family of APIs have been removed.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000630
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000631- The "u#" parser marker will now pass through Unicode objects as-is
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000632 without going through the buffer API.
633
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000634- The enumerators of cmp_op have been renamed to use the prefix ``PyCmp_``.
Martin v. Löwis7198a522002-01-01 19:59:11 +0000635
Tim Peters10a3bb52001-12-25 19:07:38 +0000636- An old #define of ANY as void has been removed from pyport.h. This
637 hasn't been used since Python's pre-ANSI days, and the #define has
638 been marked as obsolete since then. SF bug 495548 says it created
639 conflicts with other packages, so keeping it around wasn't harmless.
640
Tim Petersaf8446f2001-12-21 21:36:50 +0000641- Because Python's magic number scheme broke on January 1st, we decided
642 to stop Python development. Thanks for all the fish!
643
Tim Petersfb05db22002-03-11 00:24:00 +0000644- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000645 scheme to a new one. See Python/import.c for details.
646
Tim Petersaf8446f2001-12-21 21:36:50 +0000647New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000648-------------
Tim Petersaf8446f2001-12-21 21:36:50 +0000649
Martin v. Löwisf90ae202002-06-11 06:22:31 +0000650- AtheOS is now supported.
651
Andrew MacIntyre161ad0e2002-08-04 07:25:58 +0000652- the EMX runtime environment on OS/2 is now supported.
653
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000654- GNU/Hurd is now supported.
655
Tim Petersaf8446f2001-12-21 21:36:50 +0000656Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000657-----
658
659Yet to be written.
Tim Petersaf8446f2001-12-21 21:36:50 +0000660
661Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000662-------
Tim Petersaf8446f2001-12-21 21:36:50 +0000663
Tim Peters08e72952002-04-16 20:48:01 +0000664- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
665 of that has been fixed in the installer (disabled Wise's "delete in-
666 use files" uninstall option).
667
Guido van Rossum181e41a2002-04-06 00:23:25 +0000668- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
669
Tim Peters33187922002-04-04 20:02:04 +0000670- The installer now installs Start menu shortcuts under (the local
671 equivalent of) "All Users" when doing an Admin install.
672
Tim Petersfb05db22002-03-11 00:24:00 +0000673- file.truncate([newsize]) now works on Windows for all newsize values.
674 It used to fail if newsize didn't fit in 32 bits, reflecting a
675 limitation of MS _chsize (which is no longer used).
676
Tim Petersab034fa2002-02-01 11:27:43 +0000677- os.waitpid() is now implemented for Windows, and can be used to block
678 until a specified process exits. This is similar to, but not exactly
679 the same as, os.waitpid() on POSIX systems. If you're waiting for
680 a specific process whose pid was obtained from one of the spawn()
681 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000682 See the docs for details. The docs were changed to clarify that
683 spawn functions return, and waitpid requires, a process handle on
684 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000685
Tim Peters11bd9942002-02-01 00:52:29 +0000686- New tempfile.TemporaryFile implementation for Windows: this doesn't
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000687 need a TemporaryFileWrapper wrapper anymore, and should be immune
Tim Peters11bd9942002-02-01 00:52:29 +0000688 to a nasty problem: before 2.3, if you got a temp file on Windows, it
689 got wrapped in an object whose close() method first closed the
690 underlying file, then deleted the file. This usually worked fine.
691 However, the spawn family of functions on Windows create (at a low C
692 level) the same set of open files in the spawned process Q as were
693 open in the spawning process P. If a temp file f was among them, then
694 doing f.close() in P first closed P's C-level file handle on f, but Q's
695 C-level file handle on f remained open, so the attempt in P to delete f
696 blew up with a "Permission denied" error (Windows doesn't allow
697 deleting open files). This was surprising, subtle, and difficult to
698 work around.
699
700- The os module now exports all the symbolic constants usable with the
701 low-level os.open() on Windows: the new constants in 2.3 are
702 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
703 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
704 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
705 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
706 (so specify both if you want both; note that neither is useful unless
707 specified with O_CREAT too).
708
Tim Petersaf8446f2001-12-21 21:36:50 +0000709Mac
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000710----
711
712Yet to be written.
Tim Petersaf8446f2001-12-21 21:36:50 +0000713
714
Tim Peters909c0912001-12-14 23:16:18 +0000715What's New in Python 2.2 final?
Tim Peters909c0912001-12-14 23:16:18 +0000716===============================
717
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000718*Release date: 21-Dec-2001*
719
Tim Peters909c0912001-12-14 23:16:18 +0000720Type/class unification and new-style classes
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000721--------------------------------------------
Tim Peters909c0912001-12-14 23:16:18 +0000722
Barry Warsaw52acb492001-12-21 20:04:22 +0000723- pickle.py, cPickle: allow pickling instances of new-style classes
724 with a custom metaclass.
725
Tim Peters909c0912001-12-14 23:16:18 +0000726Core and builtins
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000727-----------------
Tim Peters909c0912001-12-14 23:16:18 +0000728
Barry Warsaw52acb492001-12-21 20:04:22 +0000729- weakref proxy object: when comparing, unwrap both arguments if both
730 are proxies.
731
Tim Peters909c0912001-12-14 23:16:18 +0000732Extension modules
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000733-----------------
Tim Peters909c0912001-12-14 23:16:18 +0000734
Barry Warsaw52acb492001-12-21 20:04:22 +0000735- binascii.b2a_base64(): fix a potential buffer overrun when encoding
736 very short strings.
737
738- cPickle: the obscure "fast" mode was suspected of causing stack
739 overflows on the Mac. Hopefully fixed this by setting the recursion
740 limit much smaller. If the limit is too low (it only affects
741 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
742 when compiling cPickle.c (or in pyconfig.h).
743
Tim Peters909c0912001-12-14 23:16:18 +0000744Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000745-------
Tim Peters909c0912001-12-14 23:16:18 +0000746
Barry Warsaw52acb492001-12-21 20:04:22 +0000747- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
748 close or delete time).
749
750- rfc822.py: fixed a bug where the address '<>' was converted to None
751 instead of an empty string (also fixes the email.Utils module).
752
753- xmlrpclib.py: version 1.0.0; uses precision for doubles.
754
755- test suite: the pickle and cPickle tests were not executing any code
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000756 when run from the standard regression test.
Barry Warsaw52acb492001-12-21 20:04:22 +0000757
Tim Peters909c0912001-12-14 23:16:18 +0000758Tools/Demos
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000759-----------
Tim Peters909c0912001-12-14 23:16:18 +0000760
761Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000762-----
Tim Peters909c0912001-12-14 23:16:18 +0000763
764C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000765-----
Tim Peters909c0912001-12-14 23:16:18 +0000766
767New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000768-------------
Tim Peters909c0912001-12-14 23:16:18 +0000769
770Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000771-----
Tim Peters909c0912001-12-14 23:16:18 +0000772
773Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000774-------
Tim Peters909c0912001-12-14 23:16:18 +0000775
Barry Warsaw52acb492001-12-21 20:04:22 +0000776- distutils package: fixed broken Windows installers (bdist_wininst).
777
778- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
779 instances are deleted at process exit time.
780
781- socket.py: prevent mysterious warnings when socket instances are
782 deleted at process exit time.
783
784- posixmodule.c: fix a Windows crash with stat() of a filename ending
785 in backslash.
786
Tim Peters909c0912001-12-14 23:16:18 +0000787Mac
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000788----
Tim Peters909c0912001-12-14 23:16:18 +0000789
Barry Warsaw52acb492001-12-21 20:04:22 +0000790- The Carbon toolbox modules have been upgraded to Universal Headers
791 3.4, and experimental CoreGraphics and CarbonEvents modules have
792 been added. All only for framework-enabled MacOSX.
793
Tim Peters909c0912001-12-14 23:16:18 +0000794
Tim Peters6272dfd2001-12-13 19:34:00 +0000795What's New in Python 2.2c1?
Tim Petersb3c9af12001-11-17 00:21:57 +0000796===========================
797
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000798*Release date: 14-Dec-2001*
799
Tim Petersb3c9af12001-11-17 00:21:57 +0000800Type/class unification and new-style classes
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000801--------------------------------------------
Tim Petersb3c9af12001-11-17 00:21:57 +0000802
Barry Warsaw06557452001-12-14 20:47:12 +0000803- Guido's tutorial introduction to the new type/class features has
804 been extensively updated. See
805
806 http://www.python.org/2.2/descrintro.html
807
808 That remains the primary documentation in this area.
809
Guido van Rossum33bab012001-12-05 22:45:48 +0000810- Fixed a leak: instance variables declared with __slots__ were never
811 deleted!
812
Guido van Rossum4b800852001-12-03 00:54:52 +0000813- The "delete attribute" method of descriptor objects is called
814 __delete__, not __del__. In previous releases, it was mistakenly
815 called __del__, which created an unfortunate overloading condition
816 with finalizers. (The "get attribute" and "set attribute" methods
817 are still called __get__ and __set__, respectively.)
818
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000819- Some subtle issues with the super built-in were fixed:
820
821 (a) When super itself is subclassed, its __get__ method would still
822 return an instance of the base class (i.e., of super).
823
824 (b) super(C, C()).__class__ would return C rather than super. This
825 is confusing. To fix this, I decided to change the semantics of
826 super so that it only applies to code attributes, not to data
827 attributes. After all, overriding data attributes is not
828 supported anyway.
829
830 (c) The __get__ method didn't check whether the argument was an
831 instance of the type used in creation of the super instance.
832
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000833- Previously, hash() of an instance of a subclass of a mutable type
834 (list or dictionary) would return some value, rather than raising
835 TypeError. This has been fixed. Also, directly calling
836 dict.__hash__ and list.__hash__ now raises the same TypeError
837 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000838
Guido van Rossumd331cb52001-12-05 19:46:42 +0000839- New-style objects now support deleting their __dict__. This is for
840 all intents and purposes equivalent to assigning a brand new empty
841 dictionary, but saves space if the object is not used further.
842
Tim Petersb3c9af12001-11-17 00:21:57 +0000843Core and builtins
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000844-----------------
Tim Petersb3c9af12001-11-17 00:21:57 +0000845
Tim Peters3caca232001-12-06 06:23:26 +0000846- -Qnew now works as documented in PEP 238: when -Qnew is passed on
847 the command line, all occurrences of "/" use true division instead
848 of classic division. See the PEP for details. Note that "all"
849 means all instances in library and 3rd-party modules, as well as in
850 your own code. As the PEP says, -Qnew is intended for use only in
851 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000852 Note that test_coercion.py in the standard Python test suite fails
853 under -Qnew; this is expected, and won't be repaired until true
854 division becomes the default (in the meantime, test_coercion is
855 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000856
Fred Drake6c01e252001-12-14 17:08:12 +0000857- complex() now only allows the first argument to be a string
858 argument, and raises TypeError if either the second arg is a string
859 or if the second arg is specified when the first is a string.
860
Tim Petersb3c9af12001-11-17 00:21:57 +0000861Extension modules
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000862-----------------
Tim Petersb3c9af12001-11-17 00:21:57 +0000863
Martin v. Löwis560da622001-11-24 09:24:51 +0000864- gc.get_referents was renamed to gc.get_referrers.
865
Tim Petersb3c9af12001-11-17 00:21:57 +0000866Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000867-------
Tim Petersb3c9af12001-11-17 00:21:57 +0000868
Tim Peters25059d32001-12-07 20:35:43 +0000869- Functions in the os.spawn() family now release the global interpreter
870 lock around calling the platform spawn. They should always have done
871 this, but did not before 2.2c1. Multithreaded programs calling
872 an os.spawn function with P_WAIT will no longer block all Python threads
873 until the spawned program completes. It's possible that some programs
874 relies on blocking, although more likely by accident than by design.
875
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000876- webbrowser defaults to netscape.exe on OS/2 now.
877
Martin v. Löwis652e1912001-11-25 14:50:56 +0000878- Tix.ResizeHandle exposes detach_widget, hide, and show.
879
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000880- The charset alias windows_1252 has been added.
881
Barry Warsaw06557452001-12-14 20:47:12 +0000882- types.StringTypes is a tuple containing the defined string types;
883 usually this will be (str, unicode), but if Python was compiled
884 without Unicode support it will be just (str,).
885
886- The pulldom and minidom modules were synchronized to PyXML.
887
Tim Petersb3c9af12001-11-17 00:21:57 +0000888Tools/Demos
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000889-----------
Tim Petersb3c9af12001-11-17 00:21:57 +0000890
Barry Warsaw06557452001-12-14 20:47:12 +0000891- A new script called Tools/scripts/google.py was added, which fires
892 off a search on Google.
893
Tim Petersb3c9af12001-11-17 00:21:57 +0000894Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000895-----
Tim Petersb3c9af12001-11-17 00:21:57 +0000896
Barry Warsaw06557452001-12-14 20:47:12 +0000897- Note that release builds of Python should arrange to define the
898 preprocessor symbol NDEBUG on the command line (or equivalent).
899 In the 2.2 pre-release series we tried to define this by magic in
900 Python.h instead, but it proved to cause problems for extension
901 authors. The Unix, Windows and Mac builds now all define NDEBUG in
902 release builds via cmdline (or equivalent) instead. Ports to
903 other platforms should do likewise.
904
Jack Jansen1999ef42001-12-06 21:47:20 +0000905- It is no longer necessary to use --with-suffix when building on a
906 case-insensitive file system (such as Mac OS X HFS+). In the build
907 directory an extension is used, but not in the installed python.
908
Tim Petersb3c9af12001-11-17 00:21:57 +0000909C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000910-----
Tim Petersb3c9af12001-11-17 00:21:57 +0000911
Tim Petersf582b822001-12-11 18:51:08 +0000912- New function PyDict_MergeFromSeq2() exposes the builtin dict
913 constructor's logic for updating a dictionary from an iterable object
914 producing key-value pairs.
915
Tim Peterscffed4b2001-11-29 03:26:37 +0000916- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000917 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000918 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
919 dump core in some bad cases. This has been repaired. As a result,
920 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
921 previously went unchallenged.
922
Tim Petersb3c9af12001-11-17 00:21:57 +0000923New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000924-------------
Tim Petersb3c9af12001-11-17 00:21:57 +0000925
926Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000927-----
Tim Petersb3c9af12001-11-17 00:21:57 +0000928
929Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000930-------
Tim Petersb3c9af12001-11-17 00:21:57 +0000931
932Mac
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000933----
Tim Petersb3c9af12001-11-17 00:21:57 +0000934
Jack Jansenffa260f2001-12-06 21:14:00 +0000935- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
936 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000937
Barry Warsaw06557452001-12-14 20:47:12 +0000938- Changed logic for finding python home in Mac OS X framework Pythons.
939 Now sys.executable points to the executable again, in stead of to
940 the shared library. The latter is used only for locating the python
941 home.
942
943
Tim Peters84362bc2001-10-19 17:55:30 +0000944What's New in Python 2.2b2?
Tim Peters84362bc2001-10-19 17:55:30 +0000945===========================
946
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000947*Release date: 16-Nov-2001*
948
Tim Peters84362bc2001-10-19 17:55:30 +0000949Type/class unification and new-style classes
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000950--------------------------------------------
Tim Peters84362bc2001-10-19 17:55:30 +0000951
Guido van Rossum3d27df02001-11-15 20:27:54 +0000952- Multiple inheritance mixing new-style and classic classes in the
953 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000954
955 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000956 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000957
958 The MRO (method resolution order) for each base class is respected
959 according to its kind, but the MRO for the derived class is computed
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000960 using new-style MRO rules if any base class is a new-style class.
Tim Peters76f7fe32001-11-15 20:02:21 +0000961 This needs to be documented.
962
Tim Petersa427a2b2001-10-29 22:25:45 +0000963- The new builtin dictionary() constructor, and dictionary type, have
964 been renamed to dict. This reflects a decade of common usage.
965
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000966- dict() now accepts an iterable object producing 2-sequences. For
967 example, dict(d.items()) == d for any dictionary d. The argument,
968 and the elements of the argument, can be any iterable objects.
969
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000970- New-style classes can now have a __del__ method, which is called
971 when the instance is deleted (just like for classic classes).
972
Guido van Rossum12d955c2001-10-26 14:56:06 +0000973- Assignment to object.__dict__ is now possible, for objects that are
974 instances of new-style classes that have a __dict__ (unless the base
975 class forbids it).
976
Guido van Rossumc8e56452001-10-22 00:43:43 +0000977- Methods of built-in types now properly check for keyword arguments
978 (formerly these were silently ignored). The only built-in methods
979 that take keyword arguments are __call__, __init__ and __new__.
980
Guido van Rossum86443212001-10-27 22:28:54 +0000981- The socket function has been converted to a type; see below.
982
Tim Peters84362bc2001-10-19 17:55:30 +0000983Core and builtins
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000984-----------------
Tim Peters84362bc2001-10-19 17:55:30 +0000985
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000986- Assignment to __debug__ raises SyntaxError at compile-time. This
987 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000988 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000989
Guido van Rossum12d955c2001-10-26 14:56:06 +0000990- Clarified the error messages for unsupported operands to an operator
991 (like 1 + '').
992
Tim Peters84362bc2001-10-19 17:55:30 +0000993Extension modules
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +0000994-----------------
Tim Peters84362bc2001-10-19 17:55:30 +0000995
Tim Peters5ebfd362001-11-13 23:11:19 +0000996- mmap has a new keyword argument, "access", allowing a uniform way for
997 both Windows and Unix users to create read-only, write-through and
998 copy-on-write memory mappings. This was previously possible only on
999 Unix. A new keyword argument was required to support this in a
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001000 uniform way because the mmap() signatures had diverged across
Tim Peters5ebfd362001-11-13 23:11:19 +00001001 platforms. Thanks to Jay T Miller for repairing this!
1002
Tim Peters169ded02001-11-03 19:57:21 +00001003- By default, the gc.garbage list now contains only those instances in
1004 unreachable cycles that have __del__ methods; in 2.1 it contained all
1005 instances in unreachable cycles. "Instances" here has been generalized
1006 to include instances of both new-style and old-style classes.
1007
Guido van Rossum12d955c2001-10-26 14:56:06 +00001008- The socket module defines a new method for socket objects,
1009 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +00001010 send() until all data has been sent. Also, the socket function has
1011 been converted to a subclassable type, like list and tuple (etc.)
1012 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +00001013
1014- Various bugfixes to the curses module. There is now a test suite
1015 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +00001016
Guido van Rossum692adf12001-10-30 03:03:03 +00001017- binascii.b2a_base64 no longer places an arbitrary restriction of 57
1018 bytes on its input.
1019
Tim Peters84362bc2001-10-19 17:55:30 +00001020Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001021-------
Tim Peters84362bc2001-10-19 17:55:30 +00001022
Tim Peters5ebfd362001-11-13 23:11:19 +00001023- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +00001024 convenience function.
1025
Tim Peters75335872001-11-03 19:35:43 +00001026- Symbolic group names in regular expressions must be unique. For
1027 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
1028 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +00001029 Python 2.2 detects this error at regexp compilation time;
1030 previously, the error went undetected, and results were
1031 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
1032 pattern.subn() methods have been rewritten in C. Also, an
1033 experimental function/method finditer() has been added, which works
1034 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +00001035
Martin v. Löwisb7b32602001-11-02 23:48:20 +00001036- Tix exposes more commands through the classes DirSelectBox,
1037 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
1038 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
1039 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
1040
Tim Peters98791af2001-10-23 01:59:54 +00001041- Traceback objects are now scanned by cyclic garbage collection, so
1042 cycles created by casual use of sys.exc_info() no longer cause
1043 permanent memory leaks (provided garbage collection is enabled).
1044
Guido van Rossum49192142001-10-24 20:51:44 +00001045- os.extsep -- a new variable needed by the RISCOS support. It is the
1046 separator used by extensions, and is '.' on all platforms except
1047 RISCOS, where it is '/'. There is no need to use this variable
1048 unless you have a masochistic desire to port your code to RISCOS.
1049
Barry Warsaw012852b2001-11-16 16:17:27 +00001050- mimetypes.py has optional support for non-standard, but commonly
1051 found types. guess_type() and guess_extension() now accept an
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001052 optional 'strict' flag, defaulting to true, which controls whether
Barry Warsaw012852b2001-11-16 16:17:27 +00001053 recognize non-standard types or not. A few non-standard types we
1054 know about have been added. Also, when run as a script, there are
1055 new -l and -e options.
1056
1057- statcache is now deprecated.
1058
1059- email.Utils.formatdate() now produces the preferred RFC 2822 style
1060 dates with numeric timezones (it used to produce obsolete dates
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001061 hard coded to "GMT" timezone). An optional 'localtime' flag is
Barry Warsaw012852b2001-11-16 16:17:27 +00001062 added to produce dates in the local timezone, with daylight savings
1063 time properly taken into account.
1064
1065- In pickle and cPickle, instead of masking errors in load() by
1066 transforming them into SystemError, we let the original exception
1067 propagate out. Also, implement support for __safe_for_unpickling__
1068 in pickle, as it already was supported in cPickle.
1069
Tim Peters84362bc2001-10-19 17:55:30 +00001070Tools/Demos
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001071-----------
Tim Peters84362bc2001-10-19 17:55:30 +00001072
1073Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001074-----
Tim Peters84362bc2001-10-19 17:55:30 +00001075
Barry Warsaw012852b2001-11-16 16:17:27 +00001076- The dbm module is built using libdb1 if available. The bsddb module
1077 is built with libdb3 if available.
1078
1079- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
1080
Tim Peters84362bc2001-10-19 17:55:30 +00001081C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001082-----
Tim Peters84362bc2001-10-19 17:55:30 +00001083
Tim Peters1fc240e2001-10-26 05:06:50 +00001084- New function PySequence_Fast_GET_SIZE() returns the size of a non-
1085 NULL result from PySequence_Fast(), more quickly than calling
1086 PySequence_Size().
1087
Barry Warsaw012852b2001-11-16 16:17:27 +00001088- New argument unpacking function PyArg_UnpackTuple() added.
1089
1090- New functions PyObject_CallFunctionObjArgs() and
1091 PyObject_CallMethodObjArgs() have been added to make it more
1092 convenient and efficient to call functions and methods from C.
1093
1094- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
1095 possible that this will propagate errors it didn't before.
1096
1097- New function PyObject_CheckReadBuffer(), which returns true if its
1098 argument supports the single-segment readable buffer interface.
1099
Tim Peters84362bc2001-10-19 17:55:30 +00001100New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001101-------------
Tim Peters84362bc2001-10-19 17:55:30 +00001102
Guido van Rossum86443212001-10-27 22:28:54 +00001103- We've finally confirmed that this release builds on HP-UX 11.00,
1104 *with* threads, and passes the test suite.
1105
Tim Peters7a33d8b2001-11-05 02:51:07 +00001106- Thanks to a series of patches from Michael Muller, Python may build
1107 again under OS/2 Visual Age C++.
1108
Guido van Rossum49192142001-10-24 20:51:44 +00001109- Updated RISCOS port by Dietmar Schwertberger.
1110
Tim Peters84362bc2001-10-19 17:55:30 +00001111Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001112-----
Tim Peters84362bc2001-10-19 17:55:30 +00001113
Andrew M. Kuchling15e03532001-10-22 16:37:10 +00001114- Added a test script for the curses module. It isn't run automatically;
1115 regrtest.py must be run with '-u curses' to enable it.
1116
Tim Peters84362bc2001-10-19 17:55:30 +00001117Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001118-------
Tim Peters84362bc2001-10-19 17:55:30 +00001119
Barry Warsaw012852b2001-11-16 16:17:27 +00001120Mac
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001121----
Barry Warsaw012852b2001-11-16 16:17:27 +00001122
1123- PythonScript has been moved to unsupported and is slated to be
1124 removed completely in the next release.
1125
1126- It should now be possible to build applets that work on both OS9 and
1127 OSX.
1128
1129- The core is now linked with CoreServices not Carbon; as a side
1130 result, default 8bit encoding on OSX is now ASCII.
1131
1132- Python should now build on OSX 10.1.1
1133
Tim Peters84362bc2001-10-19 17:55:30 +00001134
Tim Petersabf925f2001-09-28 21:53:42 +00001135What's New in Python 2.2b1?
Tim Petersabf925f2001-09-28 21:53:42 +00001136===========================
1137
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001138*Release date: 19-Oct-2001*
1139
Tim Petersabf925f2001-09-28 21:53:42 +00001140Type/class unification and new-style classes
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001141--------------------------------------------
Tim Petersabf925f2001-09-28 21:53:42 +00001142
Guido van Rossum687ae002001-10-15 22:03:32 +00001143- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001144 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +00001145 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001146 remains: the __dict__ of a new-style class is a read-only proxy; you
1147 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +00001148 __defined__ attribute of new-style types no longer exists, for lack
1149 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001150 future a __cache__ may be resurrected with a similar function, if I
1151 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +00001152
Tim Peters1c9ca872001-10-04 06:43:12 +00001153- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
1154 always returned None, even when there was a class docstring).
1155
1156- doctest now finds and runs docstrings attached to new-style classes,
1157 class methods, static methods, and properties.
1158
Guido van Rossum9074ef62001-10-16 21:34:49 +00001159Core and builtins
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001160-----------------
Tim Petersabf925f2001-09-28 21:53:42 +00001161
Guido van Rossuma8bcf802001-10-15 15:53:58 +00001162- A very subtle syntactical pitfall in list comprehensions was fixed.
1163 For example: [a+b for a in 'abc', for b in 'def']. The comma in
1164 this example is a mistake. Previously, this would silently let 'a'
1165 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
1166 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
1167 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
1168 Note that [a for a in <singleton>] is a convoluted way to say
1169 [<singleton>] anyway, so it's not like any expressiveness is lost.
1170
Guido van Rossum9074ef62001-10-16 21:34:49 +00001171- getattr(obj, name, default) now only catches AttributeError, as
1172 documented, rather than returning the default value for all
1173 exceptions (which could mask bugs in a __getattr__ hook, for
1174 example).
1175
Fred Drakecb7a6b52001-10-22 18:41:51 +00001176- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +00001177 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001178 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +00001179 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +00001180
Guido van Rossum1c486092001-10-19 02:05:35 +00001181- unicode(obj) now behaves more like str(obj), accepting arbitrary
1182 objects, and calling a __unicode__ method if it exists.
1183 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +00001184 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +00001185
Barry Warsawf6fb1712001-10-19 05:35:40 +00001186- isinstance() now allows any object as the first argument and a
1187 class, a type or something with a __bases__ tuple attribute for the
1188 second argument. The second argument may also be a tuple of a
1189 class, type, or something with __bases__, in which case isinstance()
1190 will return true if the first argument is an instance of any of the
1191 things contained in the second argument tuple. E.g.
1192
1193 isinstance(x, (A, B))
1194
1195 returns true if x is an instance of A or B.
1196
Guido van Rossum9074ef62001-10-16 21:34:49 +00001197Extension modules
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001198-----------------
Guido van Rossum9074ef62001-10-16 21:34:49 +00001199
1200- thread.start_new_thread() now returns the thread ID (previously None).
1201
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001202- binascii has now two quopri support functions, a2b_qp and b2a_qp.
1203
Guido van Rossumc524d952001-10-19 01:31:59 +00001204- readline now supports setting the startup_hook and the
1205 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +00001206
Guido van Rossumc524d952001-10-19 01:31:59 +00001207- os and posix supports chroot(), setgroups() and unsetenv() where
1208 available. The stat(), fstat(), statvfs() and fstatvfs() functions
1209 now return "pseudo-sequences" -- the various fields can now be
1210 accessed as attributes (e.g. os.stat("/").st_mtime) but for
1211 backwards compatibility they also behave as a fixed-length sequence.
1212 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +00001213 attributes.
1214
1215- time: localtime(), gmtime() and strptime() now return a
1216 pseudo-sequence similar to the os.stat() return value, with
1217 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +00001218
Guido van Rossum9074ef62001-10-16 21:34:49 +00001219- Decompression objects in the zlib module now accept an optional
1220 second parameter to decompress() that specifies the maximum amount
1221 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +00001222
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001223- optional SSL support in the socket module now exports OpenSSL
1224 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
1225 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +00001226 automatically seed its PRNG. Also, the keyfile and certfile
1227 arguments to socket.ssl() are now optional.
1228
1229- posixmodule (and by extension, the os module on POSIX platforms) now
1230 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001231
Guido van Rossum9074ef62001-10-16 21:34:49 +00001232Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001233-------
Guido van Rossum3c288632001-10-16 21:13:49 +00001234
Tim Peters7402f792001-10-02 03:53:41 +00001235- doctest now excludes functions and classes not defined by the module
1236 being tested, thanks to Tim Hochberg.
1237
Fred Drakecb7a6b52001-10-22 18:41:51 +00001238- HotShot, a new profiler implemented using a C-based callback, has
1239 been added. This substantially reduces the overhead of profiling,
1240 but it is still quite preliminary. Support modules and
1241 documentation will be added in upcoming releases (before 2.2 final).
1242
Guido van Rossumc4b09b42001-10-04 10:19:00 +00001243- profile now produces correct output in situations where an exception
1244 raised in Python is cleared by C code (e.g. hasattr()). This used
1245 to cause wrong output, including spurious claims of recursive
1246 functions and attribution of time spent to the wrong function.
1247
Tim Peters0a1fc4e2001-10-07 03:12:08 +00001248 The code and documentation for the derived OldProfile and HotProfile
1249 profiling classes was removed. The code hasn't worked for years (if
1250 you tried to use them, they raised exceptions). OldProfile
1251 intended to reproduce the behavior of the profiler Python used more
1252 than 7 years ago, and isn't interesting anymore. HotProfile intended
1253 to provide a faster profiler (but producing less information), and
1254 that's a worthy goal we intend to meet via a different approach (but
1255 without losing information).
1256
Tim Peterscce092d2001-10-09 05:31:56 +00001257- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +00001258 a much better system-specific calibration constant. The constant can
1259 now be specified in an instance constructor, or as a Profile class or
1260 instance variable, instead of by editing profile.py's source code.
1261 Calibration must still be done manually (see the docs for the profile
1262 module).
1263
1264 Note that Profile.calibrate() must be overriden by subclasses.
1265 Improving the accuracy required exploiting detailed knowledge of
1266 profiler internals; the earlier method abstracted away the details
1267 and measured a simplified model instead, but consequently computed
1268 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +00001269
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001270- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +00001271 which indicates whether output is intended for the header 'Q'
1272 encoding.
1273
Guido van Rossuma5343cc2001-10-18 18:02:07 +00001274- The SocketServer.ThreadingMixIn class now closes the request after
1275 finish_request() returns. (Not when it errors out though.)
1276
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001277- The nntplib module's NNTP.body() method has grown a 'file' argument
Barry Warsawf6fb1712001-10-19 05:35:40 +00001278 to allow saving the message body to a file.
1279
1280- The email package has added a class email.Parser.HeaderParser which
1281 only parses headers and does not recurse into the message's body.
1282 Also, the module/class MIMEAudio has been added for representing
1283 audio data (contributed by Anthony Baxter).
1284
1285- ftplib should be able to handle files > 2GB.
1286
1287- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
1288 ON, and OFF.
1289
Fred Drakecb7a6b52001-10-22 18:41:51 +00001290- xml.dom.minidom NodeList objects now support the length attribute
1291 and item() method as required by the DOM specifications.
1292
Guido van Rossumed554f62001-10-02 23:15:37 +00001293Tools/Demos
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001294-----------
Guido van Rossumed554f62001-10-02 23:15:37 +00001295
1296- Demo/dns was removed. It no longer serves any purpose; a package
1297 derived from it is now maintained by Anthony Baxter, see
1298 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +00001299
Barry Warsawf6fb1712001-10-19 05:35:40 +00001300- The freeze tool has been made more robust, and two new options have
1301 been added: -X and -E.
1302
Tim Petersabf925f2001-09-28 21:53:42 +00001303Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001304-----
Tim Petersabf925f2001-09-28 21:53:42 +00001305
Barry Warsawf6fb1712001-10-19 05:35:40 +00001306- configure will use CXX in LINKCC if CXX is used to build main() and
1307 the system requires to link a C++ main using the C++ compiler.
1308
Tim Petersabf925f2001-09-28 21:53:42 +00001309C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001310-----
Tim Petersabf925f2001-09-28 21:53:42 +00001311
Guido van Rossum6c4bce32001-10-18 19:20:25 +00001312- The documentation for the tp_compare slot is updated to require that
1313 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
1314 not correct. This is not yet enforced but will be enforced in
1315 Python 2.3; even later, we may use -2 to indicate errors and +2 for
1316 "NotImplemented". Right now, -1 should be used for an error return.
1317
Tim Petersd38b1c72001-09-30 05:09:37 +00001318- PyLong_AsLongLong() now accepts int (as well as long) arguments.
1319 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
1320 as long) arguments.
1321
Guido van Rossum3c288632001-10-16 21:13:49 +00001322- PyThread_start_new_thread() now returns a long int giving the thread
1323 ID, if one can be calculated; it returns -1 for error, 0 if no
1324 thread ID is calculated (this is an incompatible change, but only
1325 the thread module used this API). This code has only really been
1326 tested on Linux and Windows; other platforms please beware (and
1327 report any bugs or strange behavior).
1328
Guido van Rossum1c486092001-10-19 02:05:35 +00001329- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
1330 input.
1331
Tim Petersabf925f2001-09-28 21:53:42 +00001332New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001333-------------
Tim Petersabf925f2001-09-28 21:53:42 +00001334
1335Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001336-----
Tim Petersabf925f2001-09-28 21:53:42 +00001337
1338Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001339-------
Tim Petersabf925f2001-09-28 21:53:42 +00001340
Tim Peters04cf1d32001-10-09 22:39:40 +00001341- Installer: If you install IDLE, and don't disable file-extension
1342 registration, a new "Edit with IDLE" context (right-click) menu entry
1343 is created for .py and .pyw files.
1344
Tim Peters1ce3cf72001-10-01 17:58:40 +00001345- The signal module now supports SIGBREAK on Windows, thanks to Steven
1346 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
1347 action remains to call Win32 ExitProcess(). This can be changed via
Skip Montanaroa2a07bc2002-09-30 15:23:01 +00001348 signal.signal(). For example::
Tim Peters1ce3cf72001-10-01 17:58:40 +00001349
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001350 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
1351 # (SIGINT) behavior.
1352 import signal
1353 signal.signal(signal.SIGBREAK, signal.default_int_handler)
Tim Peters1ce3cf72001-10-01 17:58:40 +00001354
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001355 try:
1356 while 1:
1357 pass
1358 except KeyboardInterrupt:
1359 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
1360 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
1361 # program without the possibility for any Python-level cleanup).
1362 print "Clean exit"
Tim Peters1ce3cf72001-10-01 17:58:40 +00001363
Tim Petersabf925f2001-09-28 21:53:42 +00001364
Tim Petersb07352e2001-09-08 01:25:47 +00001365What's New in Python 2.2a4?
1366===========================
1367
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001368*Release date: 28-Sep-2001*
1369
Guido van Rossum808eea72001-09-25 04:15:41 +00001370Type/class unification and new-style classes
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001371--------------------------------------------
Guido van Rossum808eea72001-09-25 04:15:41 +00001372
1373- pydoc and inspect are now aware of new-style classes;
1374 e.g. help(list) at the interactive prompt now shows proper
1375 documentation for all operations on list objects.
1376
1377- Applications using Jim Fulton's ExtensionClass module can now safely
1378 be used with Python 2.2. In particular, Zope 2.4.1 now works with
1379 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
1380 examples also work again. It is hoped that Gtk and Boost also work
1381 with 2.2a4 and beyond. (If you can confirm this, please write
1382 webmaster@python.org; if there are still problems, please open a bug
1383 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +00001384
Tim Peters66c1a522001-09-24 21:17:50 +00001385- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001386 These map to read-only attributes 'fget', 'fset', 'fdel', and '__doc__'
Tim Peters66c1a522001-09-24 21:17:50 +00001387 in the constructed property object. fget, fset and fdel weren't
1388 discoverable from Python in 2.2a3. __doc__ is new, and allows to
1389 associate a docstring with a property.
1390
Guido van Rossum808eea72001-09-25 04:15:41 +00001391- Comparison overloading is now more completely implemented. For
1392 example, a str subclass instance can properly be compared to a str
1393 instance, and it can properly overload comparison. Ditto for most
1394 other built-in object types.
1395
1396- The repr() of new-style classes has changed; instead of <type
1397 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
1398 *except* for built-in types, which are still rendered as <type
1399 'Foo'> (to avoid upsetting existing code that might parse or
1400 otherwise rely on repr() of certain type objects).
1401
1402- The repr() of new-style objects is now always <Foo object at XXX>;
1403 previously, it was sometimes <Foo instance at XXX>.
1404
1405- For new-style classes, what was previously called __getattr__ is now
1406 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001407 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +00001408 one in classic classes is defined which is called only if regular
1409 attribute access raises AttributeError; to catch *all* attribute
1410 access, you can use __getattribute__ (for new-style classes). If
1411 both are defined, __getattribute__ is called first, and if it raises
1412 AttributeError, __getattr__ is called.
1413
1414- The __class__ attribute of new-style objects can be assigned to.
1415 The new class must have the same C-level object layout as the old
1416 class.
1417
1418- The builtin file type can be subclassed now. In the usual pattern,
1419 "file" is the name of the builtin type, and file() is a new builtin
1420 constructor, with the same signature as the builtin open() function.
1421 file() is now the preferred way to open a file.
1422
1423- Previously, __new__ would only see sequential arguments passed to
1424 the type in a constructor call; __init__ would see both sequential
1425 and keyword arguments. This made no sense whatsoever any more, so
1426 now both __new__ and __init__ see all arguments.
1427
1428- Previously, hash() applied to an instance of a subclass of str or
1429 unicode always returned 0. This has been repaired.
1430
1431- Previously, an operation on an instance of a subclass of an
1432 immutable type (int, long, float, complex, tuple, str, unicode),
1433 where the subtype didn't override the operation (and so the
1434 operation was handled by the builtin type), could return that
1435 instance instead a value of the base type. For example, if s was of
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001436 a str subclass type, s[:] returned s as-is. Now it returns a str
Guido van Rossum808eea72001-09-25 04:15:41 +00001437 with the same value as s.
1438
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001439- Provisional support for pickling new-style objects has been added.
1440
Guido van Rossum808eea72001-09-25 04:15:41 +00001441Core
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001442----
Guido van Rossum808eea72001-09-25 04:15:41 +00001443
Tim Peters2c9aa5e2001-09-23 04:06:05 +00001444- file.writelines() now accepts any iterable object producing strings.
1445
Marc-André Lemburgaefd7662001-09-20 12:59:37 +00001446- PyUnicode_FromEncodedObject() now works very much like
1447 PyObject_Str(obj) in that it tries to use __str__/tp_str
1448 on the object if the object is not a string or buffer. This
1449 makes unicode() behave like str() when applied to non-string/buffer
1450 objects.
1451
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001452- PyFile_WriteObject now passes Unicode objects to the file's write
1453 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +00001454 of a print statement must support Unicode objects, i.e. they must
1455 at least convert them into ASCII strings.
1456
Guido van Rossum624c8af2001-09-18 15:21:04 +00001457- Thread scheduling on Solaris should be improved; it is no longer
1458 necessary to insert a small sleep at the start of a thread in order
1459 to let other runnable threads be scheduled.
1460
Tim Petersb07352e2001-09-08 01:25:47 +00001461Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001462-------
Tim Petersb07352e2001-09-08 01:25:47 +00001463
Marc-André Lemburgbf990172001-09-27 14:17:33 +00001464- StringIO.StringIO instances and cStringIO.StringIO instances support
1465 read character buffer compatible objects for their .write() methods.
1466 These objects are converted to strings and then handled as such
1467 by the instances.
1468
Barry Warsaw2f600732001-09-24 04:28:10 +00001469- The "email" package has been added. This is basically a port of the
1470 mimelib package <http://sf.net/projects/mimelib> with API changes
1471 and some implementations updated to use iterators and generators.
1472
Tim Peters8a9c2842001-09-22 21:30:22 +00001473- difflib.ndiff() and difflib.Differ.compare() are generators now. This
1474 restores the ability of Tools/scripts/ndiff.py to start producing output
1475 before the entire comparison is complete.
1476
Barry Warsaw58b072d2001-09-22 04:44:21 +00001477- StringIO.StringIO instances and cStringIO.StringIO instances support
1478 iteration just like file objects (i.e. their .readline() method is
1479 called for each iteration until it returns an empty string).
1480
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +00001481- The codecs module has grown four new helper APIs to access
1482 builtin codecs: getencoder(), getdecoder(), getreader(),
1483 getwriter().
1484
Guido van Rossum624c8af2001-09-18 15:21:04 +00001485- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
1486 simplifies writing XML RPC servers.
1487
Barry Warsaw647d5e82001-09-28 17:01:02 +00001488- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +00001489 after interpretation of symbolic links. On non-Unix systems, this
1490 is an alias for os.path.abspath().
1491
Tim Peters16a77ad2001-09-08 04:00:12 +00001492- operator.indexOf() (PySequence_Index() in the C API) now works with any
1493 iterable object.
1494
Guido van Rossum624c8af2001-09-18 15:21:04 +00001495- smtplib now supports various authentication and security features of
1496 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001497
Guido van Rossum624c8af2001-09-18 15:21:04 +00001498- hmac: a new module implementing keyed hashing for message
1499 authentication.
1500
1501- mimetypes now recognizes more extensions and file types. At the
1502 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001503
Guido van Rossum624c8af2001-09-18 15:21:04 +00001504- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001505 Python 2.2 bytecode generation. It has also been promoted from a
1506 Tool to a standard library package. (Tools/compiler still exists as
1507 a sample driver.)
1508
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001509Tools
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001510-----
Guido van Rossum624c8af2001-09-18 15:21:04 +00001511
Tim Petersb07352e2001-09-08 01:25:47 +00001512Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001513-----
Tim Petersb07352e2001-09-08 01:25:47 +00001514
Guido van Rossum624c8af2001-09-18 15:21:04 +00001515- Large file support (LFS) is now automatic when the platform supports
1516 it; no more manual configuration tweaks are needed. On Linux, at
1517 least, it's possible to have a system whose C library supports large
1518 files but whose kernel doesn't; in this case, large file support is
1519 still enabled but doesn't do you any good unless you upgrade your
1520 kernel or share your Python executable with another system whose
1521 kernel has large file support.
1522
1523- The configure script now supplies plausible defaults in a
1524 cross-compilation environment. This doesn't mean that the supplied
1525 values are always correct, or that cross-compilation now works
1526 flawlessly -- but it's a first step (and it shuts up most of
1527 autoconf's warnings about AC_TRY_RUN).
1528
1529- The Unix build is now a bit less chatty, courtesy of the parser
1530 generator. The build is completely silent (except for errors) when
1531 using "make -s", thanks to a -q option to setup.py.
1532
Tim Petersb07352e2001-09-08 01:25:47 +00001533C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001534-----
Tim Petersb07352e2001-09-08 01:25:47 +00001535
Guido van Rossum624c8af2001-09-18 15:21:04 +00001536- The "structmember" API now supports some new flag bits to deny read
1537 and/or write access to attributes in restricted execution mode.
1538
Tim Petersb07352e2001-09-08 01:25:47 +00001539New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001540-------------
Tim Petersb07352e2001-09-08 01:25:47 +00001541
Guido van Rossum624c8af2001-09-18 15:21:04 +00001542- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1543 (http://familiar.handhelds.org).
1544
Tim Petersb07352e2001-09-08 01:25:47 +00001545Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001546-----
Tim Petersb07352e2001-09-08 01:25:47 +00001547
Tim Peters8a9c2842001-09-22 21:30:22 +00001548- The "classic" standard tests, which work by comparing stdout to
1549 an expected-output file under Lib/test/output/, no longer stop at
1550 the first mismatch. Instead the test is run to completion, and a
1551 variant of ndiff-style comparison is used to report all differences.
1552 This is much easier to understand than the previous style of reporting.
1553
1554- The unittest-based standard tests now use regrtest's test_main()
1555 convention, instead of running as a side-effect of merely being
1556 imported. This allows these tests to be run in more natural and
1557 flexible ways as unittests, outside the regrtest framework.
1558
1559- regrtest.py is much better integrated with unittest and doctest now,
1560 especially in regard to reporting errors.
1561
Tim Petersb07352e2001-09-08 01:25:47 +00001562Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001563-------
Tim Petersb07352e2001-09-08 01:25:47 +00001564
Guido van Rossum624c8af2001-09-18 15:21:04 +00001565- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001566 that support it (NTFS under Windows 2000). See "What's New in
1567 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001568
Tim Petersb07352e2001-09-08 01:25:47 +00001569
Tim Petersedc99312001-08-22 21:36:50 +00001570What's New in Python 2.2a3?
1571===========================
1572
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001573*Release Date: 07-Sep-2001*
1574
Tim Petersedc99312001-08-22 21:36:50 +00001575Core
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001576----
Tim Petersedc99312001-08-22 21:36:50 +00001577
Tim Peters9fffa3e2001-09-04 05:14:19 +00001578- Conversion of long to float now raises OverflowError if the long is too
1579 big to represent as a C double.
1580
Tim Peters32f453e2001-09-03 08:35:41 +00001581- The 3-argument builtin pow() no longer allows a third non-None argument
1582 if either of the first two arguments is a float, or if both are of
1583 integer types and the second argument is negative (in which latter case
1584 the arguments are converted to float, so this is really the same
1585 restriction).
1586
Tim Peters5d2b77c2001-09-03 05:47:38 +00001587- The builtin dir() now returns more information, and sometimes much
1588 more, generally naming all attributes of an object, and all attributes
1589 reachable from the object via its class, and from its class's base
1590 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1591 an empty list. In 2.2a3,
1592
1593 >>> dir([])
1594 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1595 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1596 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1597 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1598 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1599 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1600 'reverse', 'sort']
1601
1602 dir(module) continues to return only the module's attributes, though.
1603
Tim Petersbdee63f2001-09-02 03:40:59 +00001604- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001605 than raising OverflowError. This is a partial implementation of PEP
1606 237. You can use -Wdefault::OverflowWarning to enable a warning for
1607 this situation, and -Werror::OverflowWarning to revert to the old
1608 OverflowError exception.
1609
Guido van Rossum61c345f2001-09-04 03:26:15 +00001610- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001611 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001612 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1613 -Qold, meaning the / operator has its classic meaning and no
1614 warnings are issued. Using -Qwarn issues a run-time warning about
1615 all uses of classic division for int and long arguments; -Qwarnall
1616 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001617 (for use with fixdiv.py).
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001618 [Note: the remainder of this item (preserved below) became
1619 obsolete in 2.2c1 -- -Qnew has global effect in 2.2] ::
1620
1621 Using -Qnew is questionable; it turns on new division by default, but
1622 only in the __main__ module. You can usefully combine -Qwarn or
1623 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1624 warns about classic division everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +00001625
Tim Petersbdee63f2001-09-02 03:40:59 +00001626- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001627 long, float, str, unicode, and tuple. (The types complex, list and
1628 dictionary can also be subclassed; this was introduced earlier.)
1629 Note that restrictions apply when subclassing immutable built-in
1630 types: you can only affect the value of the instance by overloading
1631 __new__. You can add mutable attributes, and the subclass instances
1632 will have a __dict__ attribute, but you cannot change the "value"
1633 (as implemented by the base class) of an immutable subclass instance
1634 once it is created.
1635
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001636- The dictionary constructor now takes an optional argument, a
1637 mapping-like object, and initializes the dictionary from its
1638 (key, value) pairs.
1639
Tim Petersbdee63f2001-09-02 03:40:59 +00001640- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001641 "cooperative super calls" in a multiple inheritance setting. For an
1642 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1643
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001644- A new built-in type, property, has been added. This enables the
1645 creation of "properties". These are attributes implemented by
1646 getter and setter functions (or only one of these for read-only or
1647 write-only attributes), without the need to override __getattr__.
1648 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001649
Tim Petersbdee63f2001-09-02 03:40:59 +00001650- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001651 liberalized, to allow leading zeroes. Examples of literals now
1652 legal that were SyntaxErrors before:
1653
1654 00.0 0e3 0100j 07.5 00000000000000000008.
1655
Tim Petersbdee63f2001-09-02 03:40:59 +00001656- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001657 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1658
Tim Petersedc99312001-08-22 21:36:50 +00001659Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001660-------
Tim Petersedc99312001-08-22 21:36:50 +00001661
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001662- telnetlib includes symbolic names for the options, and support for
1663 setting an option negotiation callback.
1664
Tim Petersa40c7932001-09-05 22:36:56 +00001665- The new C standard no longer requires that math libraries set errno to
1666 ERANGE on overflow. For platform libraries that exploit this new
1667 freedom, Python's overflow-checking was wholly broken. A new overflow-
1668 checking scheme attempts to repair that, but may not be reliable on all
1669 platforms (C doesn't seem to provide anything both useful and portable
1670 in this area anymore).
1671
Martin v. Löwis44f86962001-09-05 13:44:54 +00001672- Asynchronous timeout actions are available through the new class
1673 threading.Timer.
1674
Tim Peters78526162001-09-05 00:53:45 +00001675- math.log and math.log10 now return sensible results for even huge
1676 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1677
Tim Petersbdee63f2001-09-02 03:40:59 +00001678- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001679 currently held. See the docs for the imp module.
1680
Tim Petersbdee63f2001-09-02 03:40:59 +00001681- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001682 dumps containing ints written on platforms where Python ints are 8 bytes.
1683 When read on a box where Python ints are 4 bytes, such values are
1684 converted to Python longs.
1685
Tim Petersbdee63f2001-09-02 03:40:59 +00001686- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001687 code objects is no longer allowed. This plugs a security hole.
1688
Steve Purcell6091cd62001-09-06 16:05:17 +00001689- unittest.TestResult instances no longer store references to tracebacks
1690 generated by test failures. This prevents unexpected dangling references
1691 to objects that should be garbage collected between tests.
1692
Tim Petersedc99312001-08-22 21:36:50 +00001693Tools
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001694-----
Tim Petersedc99312001-08-22 21:36:50 +00001695
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001696- Tools/scripts/fixdiv.py has been added which can be used to fix
1697 division operators as per PEP 238.
1698
Tim Petersedc99312001-08-22 21:36:50 +00001699Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001700-----
Tim Petersedc99312001-08-22 21:36:50 +00001701
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001702- If you are an adventurous person using Mac OS X you may want to look at
1703 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1704 application, which can be used for experimenting with Carbon or Cocoa.
1705 Discussion of this on pythonmac-sig, please.
1706
Tim Peters7eea37e2001-09-04 22:08:56 +00001707C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001708-----
Tim Peters7eea37e2001-09-04 22:08:56 +00001709
1710- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001711
Tim Peters9fffa3e2001-09-04 05:14:19 +00001712- Note that PyLong_AsDouble can fail! This has always been true, but no
1713 callers checked for it. It's more likely to fail now, because overflow
Skip Montanaroa2a07bc2002-09-30 15:23:01 +00001714 errors are properly detected now. The proper way to check::
Tim Peters9fffa3e2001-09-04 05:14:19 +00001715
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001716 double x = PyLong_AsDouble(some_long_object);
1717 if (x == -1.0 && PyErr_Occurred()) {
1718 /* The conversion failed. */
1719 }
Tim Peters9fffa3e2001-09-04 05:14:19 +00001720
Tim Petersbdee63f2001-09-02 03:40:59 +00001721- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001722 compile but will not participate in GC. To upgrade an extension
1723 module:
1724
1725 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001726
Neil Schemenauer4042c692001-08-30 15:38:01 +00001727 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1728 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001729
Neil Schemenauer4042c692001-08-30 15:38:01 +00001730 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1731 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001732
Neil Schemenauer4042c692001-08-30 15:38:01 +00001733 - remove PyGC_HEAD_SIZE from object size calculations
1734
1735 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1736
Tim Petersbdee63f2001-09-02 03:40:59 +00001737- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001738 These can be used safely to construct string objects from a
1739 sprintf-style format string (similar to the format string supported
1740 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001741
Tim Petersedc99312001-08-22 21:36:50 +00001742New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001743-------------
Tim Petersedc99312001-08-22 21:36:50 +00001744
Tim Petersb7da0902001-09-02 23:01:43 +00001745- Stephen Hansen contributed patches sufficient to get a clean compile
1746 under Borland C (Windows), but he reports problems running it and ran
1747 out of time to complete the port. Volunteers? Expect a MemoryError
1748 when importing the types module; this is probably shallow, and
1749 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001750
Tim Petersedc99312001-08-22 21:36:50 +00001751Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001752-----
Tim Petersedc99312001-08-22 21:36:50 +00001753
1754Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001755-------
Tim Petersedc99312001-08-22 21:36:50 +00001756
Tim Peters6e13a562001-09-06 00:32:15 +00001757- Large file support is now enabled on Win32 platforms as well as on
1758 Win64. This means that, for example, you can use f.tell() and f.seek()
1759 to manipulate files larger than 2 gigabytes (provided you have enough
1760 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001761 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1762 filesize limit, and large file support makes no difference there.
1763 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1764 NTFS has no practical limit on file size, and files of any size can be
1765 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001766
Tim Petersbdee63f2001-09-02 03:40:59 +00001767- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001768 points to command.com (patch from Brian Quinlan).
1769
Tim Petersedc99312001-08-22 21:36:50 +00001770
Tim Peters20f51a72001-07-21 02:31:40 +00001771What's New in Python 2.2a2?
1772===========================
1773
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001774*Release Date: 22-Aug-2001*
1775
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001776Build
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001777-----
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001778
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001779- Tim Peters developed a brand new Windows installer using Wise 8.1,
1780 generously donated to us by Wise Solutions.
1781
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001782- configure supports a new option --enable-unicode, with the values
1783 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1784 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001785
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001786- A new configure option --enable-framework builds a Mac OS X framework,
1787 which "make frameworkinstall" will install. This provides a starting
1788 point for more mac-like functionality, join pythonmac-sig@python.org
1789 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001790
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001791- The NeXT platform is no longer supported.
1792
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001793- The 'new' module is now statically linked.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001794
Tim Peters0afb6092001-08-15 06:06:44 +00001795Tools
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001796-----
Tim Peters0afb6092001-08-15 06:06:44 +00001797
1798- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001799 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001800 the module docstring for details.
1801
Tim Peters20f51a72001-07-21 02:31:40 +00001802Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001803-----
Tim Peters20f51a72001-07-21 02:31:40 +00001804
Tim Peters5e824c32001-08-12 22:25:01 +00001805- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001806 platforms, allowing to give clearer test result output. regrtest
1807 also has optional --use/-u switch to run normally disabled tests
1808 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001809
Tim Peters20f51a72001-07-21 02:31:40 +00001810- Several new tests in the standard test suite, with special thanks to
1811 Nick Mathewson.
1812
1813Core
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001814----
Tim Peters20f51a72001-07-21 02:31:40 +00001815
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001816- The floor division operator // has been added as outlined in PEP
1817 238. The / operator still provides classic division (and will until
1818 Python 3.0) unless "from __future__ import division" is included, in
1819 which case the / operator will provide true division. The operator
1820 module provides truediv() and floordiv() functions. Augmented
1821 assignment variants are included, as are the equivalent overloadable
1822 methods and C API methods. See the PEP for a full discussion:
1823 <http://python.sf.net/peps/pep-0238.html>
1824
Tim Peters6cd6a822001-08-17 22:11:27 +00001825- Future statements are now effective in simulated interactive shells
1826 (like IDLE). This should "just work" by magic, but read Michael
1827 Hudson's "Future statements in simulated shells" PEP 264 for full
1828 details: <http://python.sf.net/peps/pep-0264.html>.
1829
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001830- The type/class unification (PEP 252-253) was integrated into the
1831 trunk and is not so tentative any more (the exact specification of
1832 some features is still tentative). A lot of work has done on fixing
1833 bugs and adding robustness and features (performance still has to
1834 come a long way).
1835
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001836- Warnings about a mismatch in the Python API during extension import
1837 now use the Python warning framework (which makes it possible to
1838 write filters for these warnings).
1839
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001840- A function's __dict__ (aka func_dict) will now always be a
1841 dictionary. It used to be possible to delete it or set it to None,
1842 but now both actions raise TypeErrors. It is still legal to set it
1843 to a dictionary object. Getting func.__dict__ before any attributes
1844 have been assigned now returns an empty dictionary instead of None.
1845
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001846- A new command line option, -E, was added which disables the use of
1847 all environment variables, or at least those that are specifically
1848 significant to Python. Usually those have a name starting with
1849 "PYTHON". This was used to fix a problem where the tests fail if
1850 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1851 older distribution.
1852
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001853Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001854-------
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001855
Tim Peters5e824c32001-08-12 22:25:01 +00001856- New class Differ and new functions ndiff() and restore() in difflib.py.
1857 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001858 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001859
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001860- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1861 value using the minimal quoting required for the value; more
1862 reliable than using xml.sax.saxutils.escape() for attribute values.
1863
1864- Readline completion support for cmd.Cmd was added.
1865
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001866- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1867
1868- Added function threading.BoundedSemaphore()
1869
1870- Added Ka-Ping Yee's cgitb.py module.
1871
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001872- The 'new' module now exposes the CO_xxx flags.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001873
Martin v. Löwis560da622001-11-24 09:24:51 +00001874- The gc module offers the get_referents function.
1875
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001876New platforms
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001877-------------
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001878
1879C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001880-----
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001881
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001882- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1883 which provide a cross-platform implementations for the
1884 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1885 the standard sprintf() and vsprintf() C lib APIs, these versions
1886 apply bounds checking on the used buffer which enhances protection
1887 against buffer overruns.
1888
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001889- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001890 and extensions using different Unicode widths is rendered next to
1891 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001892 will result in an ImportError. Unicode extensions writers must make
1893 sure to check the Unicode width compatibility in their extensions by
1894 using at least one of the mangled Unicode APIs in the extension.
1895
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001896- Two new flags METH_NOARGS and METH_O are available in method definition
1897 tables to simplify implementation of methods with no arguments and a
1898 single untyped argument. Calling such methods is more efficient than
1899 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1900 deprecated.
1901
Tim Petersc1731372001-08-04 08:12:36 +00001902Windows
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001903-------
Tim Petersc1731372001-08-04 08:12:36 +00001904
1905- "import module" now compiles module.pyw if it exists and nothing else
1906 relevant is found.
1907
Tim Peters20f51a72001-07-21 02:31:40 +00001908
Guido van Rossum55a78992001-07-17 17:22:32 +00001909What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +00001910===========================
1911
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001912*Release date: 18-Jul-2001*
1913
Tim Petersf553f892001-05-01 20:45:31 +00001914Core
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001915----
Tim Petersa814db52001-05-14 07:05:58 +00001916
Tim Peters6d6c1a32001-08-02 04:15:00 +00001917- TENTATIVELY, a large amount of code implementing much of what's
1918 described in PEP 252 (Making Types Look More Like Classes) and PEP
1919 253 (Subtyping Built-in Types) was added. This will be released
1920 with Python 2.2a1. Documentation will be provided separately
1921 through http://www.python.org/2.2/. The purpose of releasing this
1922 with Python 2.2a1 is to test backwards compatibility. It is
1923 possible, though not likely, that a decision is made not to release
1924 this code as part of 2.2 final, if any serious backwards
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00001925 incompatibilities are found during alpha testing that cannot be
Tim Peters6d6c1a32001-08-02 04:15:00 +00001926 repaired.
1927
Guido van Rossum55a78992001-07-17 17:22:32 +00001928- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001929 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001930 more 'yield' statements. See PEP 255. Since this adds a new
1931 keyword to the language, this feature must be enabled by including a
1932 future statement: "from __future__ import generators" (see PEP 236).
1933 Generators will become a standard feature in a future release
1934 (probably 2.3). Without this future statement, 'yield' remains an
1935 ordinary identifier, but a warning is issued each time it is used.
1936 (These warnings currently don't conform to the warnings framework of
1937 PEP 230; we intend to fix this in 2.2a2.)
1938
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001939- The UTF-16 codec was modified to be more RFC compliant. It will now
1940 only remove BOM characters at the start of the string and then
1941 only if running in native mode (UTF-16-LE and -BE won't remove a
1942 leading BMO character).
1943
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001944- Strings now have a new method .decode() to complement the already
1945 existing .encode() method. These two methods provide direct access
1946 to the corresponding decoders and encoders of the registered codecs.
1947
1948 To enhance the usability of the .encode() method, the special
1949 casing of Unicode object return values was dropped (Unicode objects
1950 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001951
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001952 Both methods will now return whatever the codec in charge of the
1953 requested encoding returns as object, e.g. Unicode codecs will
1954 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1955 will return u"äöü"). This enables codec writer to create codecs
1956 for various simple to use conversions.
1957
1958 New codecs were added to demonstrate these new features (the .encode()
1959 and .decode() columns indicate the type of the returned objects):
1960
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00001961 +---------+-----------+-----------+-----------------------------+
1962 |Name | .encode() | .decode() | Description |
1963 +=========+===========+===========+=============================+
1964 |uu | string | string | UU codec (e.g. for email) |
1965 +---------+-----------+-----------+-----------------------------+
1966 |base64 | string | string | base64 codec |
1967 +---------+-----------+-----------+-----------------------------+
1968 |quopri | string | string | quoted-printable codec |
1969 +---------+-----------+-----------+-----------------------------+
1970 |zlib | string | string | zlib compression |
1971 +---------+-----------+-----------+-----------------------------+
1972 |hex | string | string | 2-byte hex codec |
1973 +---------+-----------+-----------+-----------------------------+
1974 |rot-13 | string | Unicode | ROT-13 Unicode charmap codec|
1975 +---------+-----------+-----------+-----------------------------+
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001976
Mark Hammond2a0af792001-05-14 03:09:36 +00001977- Some operating systems now support the concept of a default Unicode
1978 encoding for file system operations. Notably, Windows supports 'mbcs'
1979 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001980 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001981 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001982
1983 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001984 functions that return filenames (such as os.listdir()) to return Python
1985 string objects pre-encoded using the default file system encoding for
1986 the platform. As this encoding is likely to be different from Python's
1987 default encoding, converting this name to a Unicode object before passing
1988 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001989 would attempt to use its default encoding (generally ASCII) rather than
1990 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001991
Tim Petersa814db52001-05-14 07:05:58 +00001992 In general, this change simply removes surprises when working with
1993 Unicode and the file system, making these operations work as you expect,
1994 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001995 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001996
Tim Peters61dff2b2001-05-08 15:43:37 +00001997- Float (and complex) literals in source code were evaluated to full
1998 precision only when running from a .py file; the same code loaded from a
1999 .pyc (or .pyo) file could suffer numeric differences starting at about the
2000 12th significant decimal digit. For example, on a machine with IEEE-754
2001 floating arithmetic,
2002
2003 x = 9007199254740992.0
2004 print long(x)
2005
2006 printed 9007199254740992 if run directly from .py, but 9007199254740000
2007 if from a compiled (.pyc or .pyo) file. This was due to marshal using
2008 str(float) instead of repr(float) when building code objects. marshal
2009 now uses repr(float) instead, which should reproduce floats to full
2010 machine precision (assuming the platform C float<->string I/O conversion
2011 functions are of good quality).
2012
2013 This may cause floating-point results to change in some cases, and
2014 usually for the better, but may also cause numerically unstable
2015 algorithms to break.
2016
Tim Peters2f228e72001-05-13 00:19:31 +00002017- The implementation of dicts suffers fewer collisions, which has speed
2018 benefits. However, the order in which dict entries appear in dict.keys(),
2019 dict.values() and dict.items() may differ from previous releases for a
2020 given dict. Nothing is defined about this order, so no program should
2021 rely on it. Nevertheless, it's easy to write test cases that rely on the
2022 order by accident, typically because of printing the str() or repr() of a
2023 dict to an "expected results" file. See Lib/test/test_support.py's new
2024 sortdict(dict) function for a simple way to display a dict in sorted
2025 order.
2026
Tim Peters7a3bfc32001-06-12 01:22:22 +00002027- Many other small changes to dicts were made, resulting in faster
2028 operation along the most common code paths.
2029
Guido van Rossum10315822001-05-01 20:54:30 +00002030- Dictionary objects now support the "in" operator: "x in dict" means
2031 the same as dict.has_key(x).
2032
Barry Warsaw51acc8d2001-06-26 20:12:50 +00002033- The update() method of dictionaries now accepts generic mapping
2034 objects. Specifically the argument object must support the .keys()
2035 and __getitem__() methods. This allows you to say, for example,
2036 {}.update(UserDict())
2037
Guido van Rossum10315822001-05-01 20:54:30 +00002038- Iterators were added; this is a generalized way of providing values
2039 to a for loop. See PEP 234. There's a new built-in function iter()
2040 to return an iterator. There's a new protocol to get the next value
2041 from an iterator using the next() method (in Python) or the
2042 tp_iternext slot (in C). There's a new protocol to get iterators
2043 using the __iter__() method (in Python) or the tp_iter slot (in C).
2044 Iterating (i.e. a for loop) over a dictionary generates its keys.
2045 Iterating over a file generates its lines.
2046
Tim Petersf553f892001-05-01 20:45:31 +00002047- The following functions were generalized to work nicely with iterator
Skip Montanaroa2a07bc2002-09-30 15:23:01 +00002048 arguments::
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002049
Tim Peterse63415e2001-05-08 04:38:29 +00002050 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00002051 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
2052 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00002053 join() method of strings
2054 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00002055 'x in y' and 'x not in y' (PySequence_Contains() in C API)
2056 operator.countOf() (PySequence_Count() in C API)
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002057 right-hand side of assignment statements with multiple targets, such as ::
Tim Petersd6d010b2001-06-21 02:49:55 +00002058 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00002059
Tim Petersd85e1022001-05-11 21:51:48 +00002060- Accessing module attributes is significantly faster (for example,
2061 random.random or os.path or yourPythonModule.yourAttribute).
2062
Tim Peterse63415e2001-05-08 04:38:29 +00002063- Comparing dictionary objects via == and != is faster, and now works even
2064 if the keys and values don't support comparisons other than ==.
2065
Tim Peters95bf9392001-05-10 08:32:44 +00002066- Comparing dictionaries in ways other than == and != is slower: there were
2067 insecurities in the dict comparison implementation that could cause Python
2068 to crash if the element comparison routines for the dict keys and/or
2069 values mutated the dicts. Making the code bulletproof slowed it down.
2070
Tim Peterseb28ef22001-06-02 05:27:19 +00002071- Collisions in dicts are resolved via a new approach, which can help
2072 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00002073 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00002074 faster now. Thanks to Christian Tismer for pointing out the cause and
2075 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00002076
Tim Peters52e155e2001-06-16 05:42:57 +00002077- repr() is much faster for large containers (dict, list, tuple).
2078
2079
Tim Petersa814db52001-05-14 07:05:58 +00002080Library
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002081-------
Tim Petersa814db52001-05-14 07:05:58 +00002082
Fred Drake960fdf92001-07-20 18:38:26 +00002083- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002084 were added to the string module. These a locale-independent
Fred Drake960fdf92001-07-20 18:38:26 +00002085 constants, unlike letters, lowercase, and uppercase. These are now
2086 use in appropriate locations in the standard library.
2087
Martin v. Löwisf0473d52001-07-18 16:17:16 +00002088- The flags used in dlopen calls can now be configured using
2089 sys.setdlopenflags and queried using sys.getdlopenflags.
2090
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00002091- Fredrik Lundh's xmlrpclib is now a standard library module. This
2092 provides full client-side XML-RPC support. In addition,
2093 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
2094 one asyncore-based). Thanks to Eric Raymond for the documentation.
2095
Guido van Rossum643d3912001-07-05 14:46:25 +00002096- The xrange() object is simplified: it no longer supports slicing,
2097 repetition, comparisons, efficient 'in' checking, the tolist()
2098 method, or the start, stop and step attributes. See PEP 260.
2099
Martin v. Löwisebf94db2001-06-06 06:25:40 +00002100- A new function fnmatch.filter to filter lists of file names was added.
2101
Barry Warsawffd674d2001-05-22 16:00:10 +00002102- calendar.py uses month and day names based on the current locale.
2103
Guido van Rossum2e0a6542001-05-15 02:14:44 +00002104- strop is now *really* obsolete (this was announced before with 1.6),
2105 and issues DeprecationWarning when used (except for the four items
2106 that are still imported into string.py).
2107
Tim Petersa814db52001-05-14 07:05:58 +00002108- Cookie.py now sorts key+value pairs by key in output strings.
2109
2110- pprint.isrecursive(object) didn't correctly identify recursive objects.
2111 Now it does.
2112
Tim Peters95b3f782001-05-14 18:39:41 +00002113- pprint functions now much faster for large containers (tuple, list, dict).
2114
Tim Peters7b9542a2001-06-10 23:40:19 +00002115- New 'q' and 'Q' format codes in the struct module, corresponding to C
2116 types "long long" and "unsigned long long" (on Windows, __int64). In
2117 native mode, these can be used only when the platform C compiler supports
2118 these types (when HAVE_LONG_LONG is #define'd by the Python config
2119 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00002120 In standard mode, 'q' and 'Q' are supported on all platforms, and are
2121 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00002122
Guido van Rossum83213cc2001-06-12 16:48:52 +00002123- The site module installs a new built-in function 'help' that invokes
2124 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
2125 it displays a message reminding the user to use 'help()' or
2126 'help(object)'.
2127
Tim Petersa814db52001-05-14 07:05:58 +00002128Tests
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002129-----
Tim Petersa814db52001-05-14 07:05:58 +00002130
2131- New test_mutants.py runs dict comparisons where the key and value
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002132 comparison operators mutate the dicts randomly during comparison. This
Tim Petersa814db52001-05-14 07:05:58 +00002133 rapidly causes Python to crash under earlier releases (not for the faint
2134 of heart: it can also cause Win9x to freeze or reboot!).
2135
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002136- New test_pprint.py verifies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00002137 pprint.isreadable() return sensible results. Also verifies that simple
2138 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00002139
Tim Peters4324aa32001-05-28 22:30:08 +00002140C API
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002141-----
Tim Peters4324aa32001-05-28 22:30:08 +00002142
2143- Removed the unused last_is_sticky argument from the internal
2144 _PyTuple_Resize(). If this affects you, you were cheating.
Skip Montanaroe5d7f7f2002-09-20 14:16:59 +00002145
2146----
2147
2148**(For information about older versions, consult the HISTORY file.)**