blob: c1bec1b6295e983c42131bb14a13164e7639d0fe [file] [log] [blame]
Tim Petersaf8446f2001-12-21 21:36:50 +00001What's New in Python 2.3 alpha 1?
2XXX Release date: DD-MMM-2002 XXX
3=================================
4
5Type/class unification and new-style classes
6
Guido van Rossume3438782002-08-12 03:42:03 +00007- Assignment to __class__ is disallowed if either the old and the new
8 class is a statically allocated type object (such as defined by an
9 extenson module). This prevents anomalies like 2.__class__ = bool.
10
11- New-style object creation and deallocation have been sped up
12 significantly; they are now faster than classic instance creation
13 and deallocation.
14
15- The __slots__ variable can now mention "private" names, and the
16 right thing will happen (e.g. __slots__ = ["__foo"]).
17
18- The built-ins slice() and buffer() are now callable types. The
19 types classobj (formerly class), code, function, instance, and
20 instancemethod (formerly instance-method), which have no built-in
21 names but are accessible through the types module, are now also
22 callable. The type dict-proxy is renamed to dictproxy.
23
24- Cycles going through the __class__ link of a new-style instance are
25 now detected by the garbage collector.
26
27- Classes using __slots__ are now properly garbage collected.
28 [SF bug 519621]
29
30- Tightened the __slots__ rules: a slot name must be a valid Python
31 identifier.
32
33- The constructor for the module type now requires a name argument and
34 takes an optional docstring argument. Previously, this constructor
35 ignored its arguments. As a consequence, deriving a class from a
36 module (not from the module type) is now illegal; previously this
37 created an unnamed module, just like invoking the module type did.
38 [SF bug 563060]
39
40- A new type object, 'basestring', is added. This is a common base type
41 for 'str' and 'unicode', and can be used instead of
42 types.StringTypes, e.g. to test whether something is "a string":
43 isinstance(x, basestring) is True for Unicode and 8-bit strings. This
44 is an abstract base class and cannot be instantiated directly.
45
46- Changed new-style class instantiation so that when C's __new__
47 method returns something that's not a C instance, its __init__ is
48 not called. [SF bug #537450]
49
50- Fixed super() to work correctly with class methods. [SF bug #535444]
51
52- If you try to pickle an instance of a class that has __slots__ but
53 doesn't define or override __getstate__, a TypeError is now raised.
54 This is done by adding a bozo __getstate__ to the class that always
55 raises TypeError. (Before, this would appear to be pickled, but the
56 state of the slots would be lost.)
57
Tim Petersaf8446f2001-12-21 21:36:50 +000058Core and builtins
59
Guido van Rossumf808b892002-08-16 03:38:10 +000060- Use of 'None' as a variable, argument or attribute name now
61 issues a SyntaxWarning. In the future, None may become a keyword.
62
Michael W. Hudsondd32a912002-08-15 14:59:02 +000063- SET_LINENO is gone. co_lnotab is now consulted to determine when to
64 call the trace function. C code that accessed f_lineno should call
65 PyCode_Addr2Line instead (f_lineno is still there, but not kept up
66 to date).
67
Guido van Rossum9be89462002-08-14 16:11:30 +000068- There's a new warning category, FutureWarning. This is used to warn
69 about a number of situations where the value or sign of an integer
70 result will change in Python 2.4 as a result of PEP 237 (integer
71 unification). The warnings implement stage B0 mentioned in that
72 PEP. The warnings are about the following situations:
73
74 - Octal and hex literals without 'L' prefix in the inclusive range
75 [0x80000000..0xffffffff]; these are currently negative ints, but
76 in Python 2.4 they will be positive longs with the same bit
77 pattern.
78
79 - Left shifts on integer values that cause the outcome to lose
80 bits or have a different sign than the left operand. To be
81 precise: x<<n where this currently doesn't yield the same value
82 as long(x)<<n; in Python 2.4, the outcome will be long(x)<<n.
83
84 - Conversions from ints to string that show negative values as
85 unsigned ints in the inclusive range [0x80000000..0xffffffff];
86 this affects the functions hex() and oct(), and the string
87 formatting codes %u, %o, %x, and %X. In Python 2.4, these will
88 show signed values (e.g. hex(-1) currently returns "0xffffffff";
89 in Python 2.4 it will return "-0x1").
90
Tim Petersd64c1de2002-08-12 17:36:03 +000091- When multiplying very large integers, a version of the so-called
92 Karatsuba algorithm is now used. This is most effective if the
93 inputs have roughly the same size. If they both have about N digits,
94 Karatsuba multiplication has O(N**1.58) runtime (the exponent is
95 log_base_2(3)) instead of the previous O(N**2). Measured results may
Tim Peters012c0a32002-08-16 03:40:07 +000096 be better or worse than that, depending on platform quirks. Besides
97 the O() improvement in raw instruction count, the Karatsuba algorithm
98 appears to have much better cache behavior on extremely large integers
99 (starting in the ballpark of a million bits). Note that this is a
100 simple implementation, and there's no intent here to compete with,
101 e.g., GMP. It gives a very nice speedup when it applies, but a package
102 devoted to fast large-integer arithmetic should run circles around it.
Tim Peters5af4e6c2002-08-12 02:31:19 +0000103
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +0000104- u'%c' will now raise a ValueError in case the argument is an
105 integer outside the valid range of Unicode code point ordinals.
106
Guido van Rossumdeb09362002-08-09 17:16:30 +0000107- The tempfile module has been overhauled for enhanced security. The
108 mktemp() function is now deprecated; new, safe replacements are
109 mkstemp() (for files) and mkdtemp() (for directories), and the
110 higher-level functions NamedTemporaryFile() and TemporaryFile().
111 Use of some global variables in this module is also deprecated; the
112 new functions have keyword arguments to provide the same
113 functionality. All Lib, Tools and Demo modules that used the unsafe
114 interfaces have been updated to use the safe replacements. Thanks
115 to Zack Weinberg!
116
Guido van Rossumd81a9832002-08-09 15:57:34 +0000117- When x is an object whose class implements __mul__ and __rmul__,
118 1.0*x would correctly invoke __rmul__, but 1*x would erroneously
119 invoke __mul__. This was due to the sequence-repeat code in the int
120 type. This has been fixed now.
121
Barry Warsawd79f6832002-08-06 17:01:51 +0000122- Previously, "str1 in str2" required str1 to be a string of length 1.
123 This restriction has been relaxed to allow str1 to be a string of
124 any length. Thus "'el' in 'hello world'" returns True now.
125
Guido van Rossumb57089c2002-08-06 16:20:26 +0000126- File objects are now their own iterators. For a file f, iter(f) now
127 returns f (unless f is closed), and f.next() is similar to
128 f.readline() when EOF is not reached; however, f.next() uses a
129 readahead buffer that messes up the file position, so mixing
130 f.next() and f.readline() (or other methods) doesn't work right.
131 Calling f.seek() drops the readahead buffer, but other operations
132 don't. It so happens that this gives a nice additional speed boost
133 to "for line in file:"; the xreadlines method and corresponding
Guido van Rossumbffb2ef2002-08-09 17:17:07 +0000134 module are now obsolete. Thanks to Oren Tirosh!
Guido van Rossumb57089c2002-08-06 16:20:26 +0000135
Guido van Rossumde392d32002-08-05 14:17:20 +0000136- Encoding declarations (PEP 263, phase 1) have been implemented. A
137 comment of the form "# -*- coding: <encodingname> -*-" in the first
138 or second line of a Python source file indicates the encoding.
Martin v. Löwis00f1e3f2002-08-04 17:29:52 +0000139
Tim Petersf47630f2002-08-01 02:34:51 +0000140- list.sort() has a new implementation. While cross-platform results
141 may vary, and in data-dependent ways, this is much faster on many
142 kinds of partially ordered lists than the previous implementation,
143 and reported to be just as fast on randomly ordered lists on
144 several major platforms. This sort is also stable (if A==B and A
145 precedes B in the list at the start, A precedes B after the sort too),
146 although the language definition does not guarantee stability. A
147 potential drawback is that list.sort() may require temp space of
148 len(list)*2 bytes (*4 on a 64-bit machine). It's therefore possible
149 for list.sort() to raise MemoryError now, even if a comparison function
150 does not. See <http://www.python.org/sf/587076> for full details.
151
Guido van Rossum2d5389c2002-07-23 03:44:35 +0000152- All standard iterators now ensure that, once StopIteration has been
153 raised, all future calls to next() on the same iterator will also
154 raise StopIteration. There used to be various counterexamples to
155 this behavior, which could caused confusion or subtle program
156 breakage, without any benefits. (Note that this is still an
157 iterator's responsibility; the iterator framework does not enforce
158 this.)
159
Mark Hammondc0e35152002-07-16 01:32:30 +0000160- Ctrl+C handling on Windows has been made more consistent with
161 other platforms. KeyboardInterrupt can now reliably be caught,
Tim Petersf47630f2002-08-01 02:34:51 +0000162 and Ctrl+C at an interative prompt no longer terminates the
Mark Hammondc0e35152002-07-16 01:32:30 +0000163 process under NT/2k/XP (it never did under Win9x). Ctrl+C will
Tim Peters5af4e6c2002-08-12 02:31:19 +0000164 interrupt time.sleep() in the main thread, and any child processes
165 created via the popen family (on win2k; we can't make win9x work
Mark Hammond8f3afc72002-08-10 06:26:31 +0000166 reliably) are also interrupted (as generally happens on for Linux/Unix.)
167 [SF bugs 231273, 439992 and 581232]
Mark Hammondc0e35152002-07-16 01:32:30 +0000168
Raymond Hettinger5a04aec2002-06-25 00:25:30 +0000169- Slices and repetitions of buffer objects now consistently return
170 a string. Formerly, strings would be returned most of the time,
171 but a buffer object would be returned when the repetition count
172 was one or when the slice range was all inclusive.
173
Walter Dörwald3430d702002-06-17 10:43:59 +0000174- Unicode objects in sys.path are no longer ignored but treated
175 as directory names.
176
Neal Norwitz1f68fc72002-06-14 00:50:42 +0000177- Fixed string.startswith and string.endswith builtin methods
178 so they accept negative indices. [SF bug 493951]
179
Guido van Rossumc5fe5eb2002-06-12 03:45:21 +0000180- Fixed a bug with a continue inside a try block and a yield in the
181 finally clause. [SF bug 567538]
182
Michael W. Hudson5efaf7e2002-06-11 10:55:12 +0000183- Most builtin sequences now support "extended slices", i.e. slices
Guido van Rossum2e82e712002-06-13 11:41:07 +0000184 with a third "stride" parameter. For example, "hello world"[::-1]
185 gives "dlrow olleh".
Michael W. Hudson5efaf7e2002-06-11 10:55:12 +0000186
Neal Norwitzd68f5172002-05-29 15:54:55 +0000187- A new warning PendingDeprecationWarning was added to provide
188 direction on features which are in the process of being deprecated.
189 The warning will not be printed by default. To see the pending
190 deprecations, use -Walways::PendingDeprecationWarning::
191 as a command line option or warnings.filterwarnings() in code.
192
Fred Draked0ba6362002-05-02 21:28:26 +0000193- Deprecated features of xrange objects have been removed as
194 promised. The start, stop, and step attributes and the tolist()
195 method no longer exist. xrange repetition and slicing have been
196 removed.
197
Guido van Rossum7dab2422002-04-26 19:40:56 +0000198- New builtin function enumerate(x), from PEP 279. Example:
199 enumerate("abc") is an iterator returning (0,"a"), (1,"b"), (2,"c").
200 The argument can be an arbitrary iterable object.
201
Neil Schemenauer89e3ee02002-04-26 01:58:53 +0000202- The assert statement no longer tests __debug__ at runtime. This means
203 that assert statements cannot be disabled by assigning a false value
204 to __debug__.
205
Walter Dörwald068325e2002-04-15 13:36:47 +0000206- A method zfill() was added to str and unicode, that fills a numeric
207 string to the left with zeros. For example,
208 "+123".zfill(6) -> "+00123".
209
Guido van Rossum862fe3c2002-04-15 12:36:47 +0000210- Complex numbers supported divmod() and the // and % operators, but
211 these make no sense. Since this was documented, they're being
212 deprecated now.
213
Guido van Rossum26dd8302002-04-26 20:11:29 +0000214- String and unicode methods lstrip(), rstrip() and strip() now take
215 an optional argument that specifies the characters to strip. For
216 example, "Foo!!!?!?!?".rstrip("?!") -> "Foo".
Guido van Rossum49042042002-04-13 00:59:05 +0000217
Guido van Rossumc69343b2002-04-12 19:22:48 +0000218- Added a new dict method pop(key). This removes and returns the
219 value corresponding to key. [SF patch #539949]
220
Guido van Rossum47834462002-04-04 15:21:33 +0000221- A new built-in type, bool, has been added, as well as built-in
222 names for its two values, True and False. Comparisons and sundry
223 other operations that return a truth value have been changed to
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000224 return a bool instead. Read PEP 285 for an explanation of why this
Guido van Rossum47834462002-04-04 15:21:33 +0000225 is backward compatible.
226
Guido van Rossum95b62a62002-03-29 01:07:24 +0000227- Fixed two bugs reported as SF #535905: under certain conditions,
228 deallocating a deeply nested structure could cause a segfault in the
229 garbage collector, due to interaction with the "trashcan" code;
230 access to the current frame during destruction of a local variable
231 could access a pointer to freed memory.
232
Guido van Rossumfe0ca4a2002-06-18 21:20:13 +0000233- The optional object allocator ("pymalloc") has been enabled by
234 default. The recommended practice for memory allocation and
235 deallocation has been streamlined. A header file is included,
236 Misc/pymemcompat.h, which can be bundled with 3rd party extensions
237 and lets them use the same API with Python versions from 1.5.2
238 onwards.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000239
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +0000240- PyErr_Display will provide file and line information for all exceptions
241 that have an attribute print_file_and_line, not just SyntaxErrors.
242
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000243- The UTF-8 codec will now encode and decode Unicode surrogates
244 correctly and without raising exceptions for unpaired ones.
245
Guido van Rossumadd88062002-08-15 14:01:14 +0000246- Universal newlines (PEP 278) is implemented. Briefly, using 'U'
247 instead of 'r' when opening a text file for reading changes the line
248 ending convention so that any of '\r', '\r\n', and '\n' is
249 recognized (even mixed in one file); all three are converted to
250 '\n', the standard Python line end character.
251
Neal Norwitz649b7592002-01-01 19:07:13 +0000252- file.xreadlines() now raises a ValueError if the file is closed:
253 Previously, an xreadlines object was returned which would raise
254 a ValueError when the xreadlines.next() method was called.
255
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000256- sys.exit() inadvertently allowed more than one argument.
Neal Norwitz0c766a02002-03-27 13:03:09 +0000257 An exception will now be raised if more than one argument is used.
258
Tim Petersaf8446f2001-12-21 21:36:50 +0000259Extension modules
260
Guido van Rossumb57089c2002-08-06 16:20:26 +0000261- The xreadlines module is slated for obsolescence.
262
Guido van Rossum79f0a102002-07-23 03:32:08 +0000263- The strptime function in the time module is now always available (a
264 Python implementation is used when the C library doesn't define it).
265
Guido van Rossum9562bcf2002-06-14 21:31:18 +0000266- The 'new' module is no longer an extension, but a Python module that
267 only exists for backwards compatibility. Its contents are no longer
268 functions but callable type objects.
269
Tim Peters81b92512002-04-29 01:37:32 +0000270- The bsddb.*open functions can now take 'None' as a filename.
Anthony Baxter83888952002-04-23 02:11:05 +0000271 This will create a temporary in-memory bsddb that won't be
Tim Peters81b92512002-04-29 01:37:32 +0000272 written to disk.
Anthony Baxter83888952002-04-23 02:11:05 +0000273
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000274- posix.lchown, posix.killpg, posix.mknod, and posix.getpgid have been
275 added where available.
Martin v. Löwis06a83e92002-04-14 10:19:44 +0000276
Martin v. Löwis2e64c342002-03-27 18:49:02 +0000277- The locale module now exposes the C library's gettext interface.
278
Tim Petersfbf74f22002-03-14 19:06:01 +0000279- A security hole ("double free") was found in zlib-1.1.3, a popular
280 third party compression library used by some Python modules. The
281 hole was quickly plugged in zlib-1.1.4, and the Windows build of
282 Python now ships with zlib-1.1.4.
283
Martin v. Löwis688357e2002-04-08 21:28:20 +0000284- pwd, grp, and resource return enhanced tuples now, with symbolic
285 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +0000286
Martin v. Löwis99866332002-03-01 10:27:01 +0000287- array.array is now a type object. A new format character
288 'u' indicates Py_UNICODE arrays. For those, .tounicode and
289 .fromunicode methods are available. Arrays now support __iadd__
290 and __imul__.
291
Neal Norwitze790eae2002-01-01 21:14:12 +0000292- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +0000293 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
294 is called.
295
Michael W. Hudson34f20ea2002-05-27 15:08:24 +0000296- signal.sigpending, signal.sigprocmask and signal.sigsuspend have
297 been added where available.
298
Tim Petersaf8446f2001-12-21 21:36:50 +0000299Library
300
Tim Peters012c0a32002-08-16 03:40:07 +0000301- random.randrange(-sys.maxint-1, sys.maxint) no longer raises
302 OverflowError. That is, it now accepts any combination of 'start'
303 and 'stop' arguments so long as each is in the range of Python's
304 bounded integers.
305
Guido van Rossum4a57c332002-08-02 18:05:20 +0000306- New "algorithms" module: heapq, implements a heap queue. Thanks to
307 Kevin O'Connor for the code and François Pinard for an entertaining
308 write-up explaining the theory and practical uses of heaps.
309
Marc-André Lemburg58e2ff22002-07-12 14:40:04 +0000310- New encoding for the Palm OS character set: palmos.
311
Tim Peters943382c2002-07-07 03:59:34 +0000312- binascii.crc32() and the zipfile module had problems on some 64-bit
313 platforms. These have been fixed. On a platform with 8-byte C longs,
314 crc32() now returns a signed-extended 4-byte result, so that its value
315 as a Python int is equal to the value computed a 32-bit platform.
316
Martin v. Löwis7d650ca2002-06-30 15:05:00 +0000317- xml.dom.minidom.toxml and toprettyxml now take an optional encoding
318 argument.
319
Guido van Rossum9f7549b2002-06-10 21:39:42 +0000320- Some fixes in the copy module: when an object is copied through its
321 __reduce__ method, there was no check for a __setstate__ method on
322 the result [SF patch 565085]; deepcopy should treat instances of
323 custom metaclasses the same way it treats instances of type 'type'
324 [SF patch 560794].
325
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000326- Sockets now support timeout mode. After s.settimeout(T), where T is
327 a float expressing seconds, subsequent operations raise an exception
328 if they cannot be completed within T seconds. To disable timeout
Guido van Rossum79f0a102002-07-23 03:32:08 +0000329 mode, use s.settimeout(None). There's also a module function,
330 socket.setdefaulttimeout(T), which sets the default for all sockets
331 created henceforth.
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000332
333- getopt.gnu_getopt was added. This supports GNU-style option
334 processing, where options can be mixed with non-option arguments.
Martin v. Löwis446a25f2002-06-06 10:58:36 +0000335
Michael W. Hudsonb0dc1a32002-06-04 18:27:35 +0000336- Stop using strings for exceptions. String objects used for
337 exceptions are now classes deriving from Exception. The objects
338 changed were: Tkinter.TclError, bdb.BdbQuit, macpath.norm_error,
339 tabnanny.NannyNag, and xdrlib.Error.
Neal Norwitzb5b5a262002-06-04 17:14:07 +0000340
Walter Dörwald474458d2002-06-04 15:16:29 +0000341- Constants BOM_UTF8, BOM_UTF16, BOM_UTF16_LE, BOM_UTF16_BE,
342 BOM_UTF32, BOM_UTF32_LE and BOM_UTF32_BE that represent the Byte
343 Order Mark in UTF-8, UTF-16 and UTF-32 encodings for little and
344 big endian systems were added to the codecs module. The old names
345 BOM32_* and BOM64_* were off by a factor of 2.
346
Guido van Rossumf9257822002-06-18 20:43:18 +0000347- Added conversion functions math.degrees() and math.radians().
Raymond Hettinger87f59ee2002-05-13 04:17:32 +0000348
Raymond Hettinger9b1df1d2002-05-12 06:07:21 +0000349- ftplib.retrlines() now tests for callback is None rather than testing
350 for False. Was causing an error when given a callback object which
351 was callable but also returned len() as zero. The change may
352 create new breakage if the caller relied on the undocumented behavior
353 and called with callback set to [] or some other False value not
354 identical to None.
355
Tim Peters46c04e12002-05-05 20:40:00 +0000356- random.gauss() uses a piece of hidden state used by nothing else,
357 and the .seed() and .whseed() methods failed to reset it. In other
358 words, setting the seed didn't completely determine the sequence of
359 results produced by random.gauss(). It does now. Programs repeatedly
360 mixing calls to a seed method with calls to gauss() may see different
361 results now.
362
Fred Drake7f781c92002-05-01 20:33:53 +0000363- The pickle.Pickler class grew a clear_memo() method to mimic that
364 provided by cPickle.Pickler.
365
Tim Peters81b92512002-04-29 01:37:32 +0000366- difflib's SequenceMatcher class now does a dynamic analysis of
367 which elements are so frequent as to constitute noise. For
368 comparing files as sequences of lines, this generally works better
369 than the IS_LINE_JUNK function, and function ndiff's linejunk
370 argument defaults to None now as a result. A happy benefit is
371 that SequenceMatcher may run much faster now when applied
372 to large files with many duplicate lines (for example, C program
373 text with lots of repeated "}" and "return NULL;" lines).
374
Guido van Rossum256705b2002-04-23 13:29:43 +0000375- New Text.dump() method in Tkinter module.
376
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000377- New distutils commands for building packagers were added to
378 support pkgtool on Solaris and swinstall on HP-UX.
379
380- distutils now has a new abstract binary packager base class
381 command/bdist_packager, which simplifies writing packagers.
382 This will hopefully provide the missing bits to encourage
383 people to submit more packagers, e.g. for Debian, FreeBSD
384 and other systems.
385
Guido van Rossumf9257822002-06-18 20:43:18 +0000386- The UTF-16, -LE and -BE stream readers now raise a
387 NotImplementedError for all calls to .readline(). Previously, they
388 used to just produce garbage or fail with an encoding error --
389 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 +0000390 work well with these.
391
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000392- compileall now supports quiet operation.
393
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000394- The BaseHTTPServer now implements optional HTTP/1.1 persistent
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000395 connections.
396
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000397- socket module: the SSL support was broken out of the main
398 _socket module C helper and placed into a new _ssl helper
399 which now gets imported by socket.py if available and working.
400
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000401- encodings package: added aliases for all supported IANA character
402 sets
403
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000404- ftplib: to safeguard the user's privacy, anonymous login will use
405 "anonymous@" as default password, rather than the real user and host
406 name.
407
Fred Drake36736122002-01-10 13:50:31 +0000408- webbrowser: tightened up the command passed to os.system() so that
409 arbitrary shell code can't be executed because a bogus URL was
410 passed in.
411
Tim Peters11bd9942002-02-01 00:52:29 +0000412- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000413 gettext.find an optional all argument. Translations will now fallback
414 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000415
Martin v. Löwis9668b932002-01-12 11:27:42 +0000416- distutils bdist commands now offer a --skip-build option.
417
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000418- warnings.warn now accepts a Warning instance as first argument.
419
Fred Drakefed7e852002-04-04 19:36:15 +0000420- The xml.sax.expatreader.ExpatParser class will no longer create
421 circular references by using itself as the locator that gets passed
422 to the content handler implementation. [SF bug #535474]
423
Barry Warsaw47f3e2c2002-05-20 00:14:24 +0000424- The email.Parser.Parser class now properly parses strings regardless
425 of their line endings, which can be any of \r, \n, or \r\n (CR, LF,
426 or CRLF). Also, the Header class's constructor default arguments
427 has changed slightly so that an explicit maxlinelen value is always
428 honored.
429
Tim Petersaf8446f2001-12-21 21:36:50 +0000430Tools/Demos
431
Fred Drake40813b12002-08-05 15:24:19 +0000432- IDLE supports the new encoding declarations (PEP 263); it can also
433 deal with legacy 8-bit files if they use the locale's encoding. It
434 allows non-ASCII strings in the interactive shell and executes them
435 in the locale's encoding.
Martin v. Löwis98ce7b72002-08-05 15:11:26 +0000436
Marc-André Lemburg46260092002-04-04 16:17:11 +0000437- freeze.py now produces binaries which can import shared modules,
438 unlike before when this failed due to missing symbol exports in
439 the generated binary.
440
Tim Petersaf8446f2001-12-21 21:36:50 +0000441Build
442
Tim Petersf47630f2002-08-01 02:34:51 +0000443- The public Python C API will generally be declared using PyAPI_FUNC
Neal Norwitz1389f3e2002-07-22 13:21:10 +0000444 and PyAPI_DATA macros, while Python extension module init functions
445 will be declared with PyMODINIT_FUNC. DL_EXPORT/DL_IMPORT macros
446 are deprecated.
447
Tim Petersc6a3ff62002-07-08 22:11:52 +0000448- A bug was fixed that could cause COUNT_ALLOCS builds to segfault, or
449 get into infinite loops, when a new-style class got garbage-collected.
450 Unfortunately, to avoid this, the way COUNT_ALLOCS works requires
451 that new-style classes be immortal in COUNT_ALLOCS builds. Note that
452 COUNT_ALLOCS is not enabled by default, in either release or debug
453 builds, and that new-style classes are immortal only in COUNT_ALLOCS
454 builds.
455
Tim Peters943382c2002-07-07 03:59:34 +0000456- Compiling out the cyclic garbage collector is no longer an option.
457 The old symbol WITH_CYCLE_GC is now ignored, and Python.h arranges
458 that it's always defined (for the benefit of any extension modules
459 that may be conditionalizing on it). A bonus is that any extension
460 type participating in cyclic gc can choose to participate in the
461 Py_TRASHCAN mechanism now too; in the absence of cyclic gc, this used
462 to require editing the core to teach the trashcan mechanism about the
463 new type.
464
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000465- According to Annex F of the current C standard,
Tim Peters1de41bf2002-07-03 03:31:20 +0000466
467 The Standard C macro HUGE_VAL and its float and long double analogs,
468 HUGE_VALF and HUGE_VALL, expand to expressions whose values are
469 positive infinities.
470
471 Python only uses the double HUGE_VAL, and only to #define its own symbol
472 Py_HUGE_VAL. Some platforms have incorrect definitions for HUGE_VAL.
473 pyport.h used to try to worm around that, but the workarounds triggered
474 other bugs on other platforms, so we gave up. If your platform defines
475 HUGE_VAL incorrectly, you'll need to #define Py_HUGE_VAL to something
476 that works on your platform. The only instance of this I'm sure about
477 is on an unknown subset of Cray systems, described here:
478
479 http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm
480
481 Presumably 2.3a1 breaks such systems. If anyone uses such a system, help!
482
Martin v. Löwisa3fb4f72002-06-09 13:33:54 +0000483- The configure option --without-doc-strings can be used to remove the
484 doc strings from the builtin functions and modules; this reduces the
485 size of the executable.
486
Guido van Rossumadd88062002-08-15 14:01:14 +0000487- The universal newlines option (PEP 278) is on by default. On Unix
488 it can be disabled by passing --without-universal-newlines to the
489 configure script. On other platforms, remove
490 WITH_UNIVERSAL_NEWLINES from pyconfig.h.
Tim Peters639295f2002-04-21 07:30:30 +0000491
Martin v. Löwis1142de32002-03-29 16:28:31 +0000492- On Unix, a shared libpython2.3.so can be created with --enable-shared.
493
Tim Peters8deda702002-03-30 10:06:07 +0000494- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
495 preprocessor symbols were eliminated. The internal decisions they
496 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000497
Fred Drake7d28b732002-05-02 21:17:00 +0000498- The tools used to build the documentation now work under Cygwin as
499 well as Unix.
500
Skip Montanaro57454e52002-06-14 20:30:31 +0000501- The bsddb and dbm module builds have been changed to try and avoid version
502 skew problems and disable linkage with Berkeley DB 1.85 unless the
503 installer knows what s/he's doing. See the section on building these
504 modules in the README file for details.
505
Tim Petersaf8446f2001-12-21 21:36:50 +0000506C API
507
Guido van Rossumfdb86482002-08-14 21:20:32 +0000508- The Py_InitModule*() functions now accept NULL for the 'methods'
509 argument. Modules without global functions are becoming more common
510 now that factories can be types rather than functions.
511
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +0000512- New C API PyUnicode_FromOrdinal() which exposes unichr() at C
513 level.
514
Thomas Heller085358a2002-07-29 14:27:41 +0000515- New functions PyErr_SetExcFromWindowsErr() and
516 PyErr_SetExcFromWindowsErrWithFilename(). Similar to
517 PyErr_SetFromWindowsErrWithFilename() and
518 PyErr_SetFromWindowsErr(), but they allow to specify
519 the exception type to raise. Available on Windows.
520
Tim Peters7c321a82002-07-09 02:57:01 +0000521- Py_FatalError() is now declared as taking a const char* argument. It
522 was previously declared without const. This should not affect working
523 code.
524
Martin v. Löwis01f94bd2002-05-08 08:44:21 +0000525- Added new macro PySequence_ITEM(o, i) that directly calls
526 sq_item without rechecking that o is a sequence and without
527 adjusting for negative indices.
528
Fred Draked0ba6362002-05-02 21:28:26 +0000529- PyRange_New() now raises ValueError if the fourth argument is not 1.
530 This is part of the removal of deprecated features of the xrange
531 object.
532
Guido van Rossum517c7d42002-04-26 02:49:14 +0000533- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
534 coercion if both arguments have the same type but this type has the
535 CHECKTYPES flag set. This is to better support proxies.
536
Neil Schemenauer9344b142002-04-12 23:00:08 +0000537- The type of tp_free has been changed from "void (*)(PyObject *)" to
538 "void (*)(void *)".
539
540- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
541
Guido van Rossum0986d822002-04-08 01:38:42 +0000542- A type can now inherit its metatype from its base type. Previously,
543 when PyType_Ready() was called, if ob_type was found to be NULL, it
544 was always set to &PyType_Type; now it is set to base->ob_type,
545 where base is tp_base, defaulting to &PyObject_Type.
546
547- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
548
Neil Schemenauerc9abc1d2002-05-08 14:14:41 +0000549- The PyCore_* family of APIs have been removed.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000550
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000551- The "u#" parser marker will now pass through Unicode objects as-is
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000552 without going through the buffer API.
553
Martin v. Löwis7198a522002-01-01 19:59:11 +0000554- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
555
Tim Peters10a3bb52001-12-25 19:07:38 +0000556- An old #define of ANY as void has been removed from pyport.h. This
557 hasn't been used since Python's pre-ANSI days, and the #define has
558 been marked as obsolete since then. SF bug 495548 says it created
559 conflicts with other packages, so keeping it around wasn't harmless.
560
Tim Petersaf8446f2001-12-21 21:36:50 +0000561- Because Python's magic number scheme broke on January 1st, we decided
562 to stop Python development. Thanks for all the fish!
563
Tim Petersfb05db22002-03-11 00:24:00 +0000564- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000565 scheme to a new one. See Python/import.c for details.
566
Tim Petersaf8446f2001-12-21 21:36:50 +0000567New platforms
568
Martin v. Löwisf90ae202002-06-11 06:22:31 +0000569- AtheOS is now supported.
570
Andrew MacIntyre161ad0e2002-08-04 07:25:58 +0000571- the EMX runtime environment on OS/2 is now supported.
572
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000573- GNU/Hurd is now supported.
574
Tim Petersaf8446f2001-12-21 21:36:50 +0000575Tests
576
577Windows
578
Tim Peters08e72952002-04-16 20:48:01 +0000579- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
580 of that has been fixed in the installer (disabled Wise's "delete in-
581 use files" uninstall option).
582
Guido van Rossum181e41a2002-04-06 00:23:25 +0000583- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
584
Tim Peters33187922002-04-04 20:02:04 +0000585- The installer now installs Start menu shortcuts under (the local
586 equivalent of) "All Users" when doing an Admin install.
587
Tim Petersfb05db22002-03-11 00:24:00 +0000588- file.truncate([newsize]) now works on Windows for all newsize values.
589 It used to fail if newsize didn't fit in 32 bits, reflecting a
590 limitation of MS _chsize (which is no longer used).
591
Tim Petersab034fa2002-02-01 11:27:43 +0000592- os.waitpid() is now implemented for Windows, and can be used to block
593 until a specified process exits. This is similar to, but not exactly
594 the same as, os.waitpid() on POSIX systems. If you're waiting for
595 a specific process whose pid was obtained from one of the spawn()
596 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000597 See the docs for details. The docs were changed to clarify that
598 spawn functions return, and waitpid requires, a process handle on
599 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000600
Tim Peters11bd9942002-02-01 00:52:29 +0000601- New tempfile.TemporaryFile implementation for Windows: this doesn't
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000602 need a TemporaryFileWrapper wrapper anymore, and should be immune
Tim Peters11bd9942002-02-01 00:52:29 +0000603 to a nasty problem: before 2.3, if you got a temp file on Windows, it
604 got wrapped in an object whose close() method first closed the
605 underlying file, then deleted the file. This usually worked fine.
606 However, the spawn family of functions on Windows create (at a low C
607 level) the same set of open files in the spawned process Q as were
608 open in the spawning process P. If a temp file f was among them, then
609 doing f.close() in P first closed P's C-level file handle on f, but Q's
610 C-level file handle on f remained open, so the attempt in P to delete f
611 blew up with a "Permission denied" error (Windows doesn't allow
612 deleting open files). This was surprising, subtle, and difficult to
613 work around.
614
615- The os module now exports all the symbolic constants usable with the
616 low-level os.open() on Windows: the new constants in 2.3 are
617 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
618 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
619 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
620 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
621 (so specify both if you want both; note that neither is useful unless
622 specified with O_CREAT too).
623
Tim Petersaf8446f2001-12-21 21:36:50 +0000624Mac
625
626
Tim Peters909c0912001-12-14 23:16:18 +0000627What's New in Python 2.2 final?
628Release date: 21-Dec-2001
629===============================
630
631Type/class unification and new-style classes
632
Barry Warsaw52acb492001-12-21 20:04:22 +0000633- pickle.py, cPickle: allow pickling instances of new-style classes
634 with a custom metaclass.
635
Tim Peters909c0912001-12-14 23:16:18 +0000636Core and builtins
637
Barry Warsaw52acb492001-12-21 20:04:22 +0000638- weakref proxy object: when comparing, unwrap both arguments if both
639 are proxies.
640
Tim Peters909c0912001-12-14 23:16:18 +0000641Extension modules
642
Barry Warsaw52acb492001-12-21 20:04:22 +0000643- binascii.b2a_base64(): fix a potential buffer overrun when encoding
644 very short strings.
645
646- cPickle: the obscure "fast" mode was suspected of causing stack
647 overflows on the Mac. Hopefully fixed this by setting the recursion
648 limit much smaller. If the limit is too low (it only affects
649 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
650 when compiling cPickle.c (or in pyconfig.h).
651
Tim Peters909c0912001-12-14 23:16:18 +0000652Library
653
Barry Warsaw52acb492001-12-21 20:04:22 +0000654- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
655 close or delete time).
656
657- rfc822.py: fixed a bug where the address '<>' was converted to None
658 instead of an empty string (also fixes the email.Utils module).
659
660- xmlrpclib.py: version 1.0.0; uses precision for doubles.
661
662- test suite: the pickle and cPickle tests were not executing any code
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000663 when run from the standard regression test.
Barry Warsaw52acb492001-12-21 20:04:22 +0000664
Tim Peters909c0912001-12-14 23:16:18 +0000665Tools/Demos
666
667Build
668
669C API
670
671New platforms
672
673Tests
674
675Windows
676
Barry Warsaw52acb492001-12-21 20:04:22 +0000677- distutils package: fixed broken Windows installers (bdist_wininst).
678
679- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
680 instances are deleted at process exit time.
681
682- socket.py: prevent mysterious warnings when socket instances are
683 deleted at process exit time.
684
685- posixmodule.c: fix a Windows crash with stat() of a filename ending
686 in backslash.
687
Tim Peters909c0912001-12-14 23:16:18 +0000688Mac
689
Barry Warsaw52acb492001-12-21 20:04:22 +0000690- The Carbon toolbox modules have been upgraded to Universal Headers
691 3.4, and experimental CoreGraphics and CarbonEvents modules have
692 been added. All only for framework-enabled MacOSX.
693
Tim Peters909c0912001-12-14 23:16:18 +0000694
Tim Peters6272dfd2001-12-13 19:34:00 +0000695What's New in Python 2.2c1?
696Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000697===========================
698
699Type/class unification and new-style classes
700
Barry Warsaw06557452001-12-14 20:47:12 +0000701- Guido's tutorial introduction to the new type/class features has
702 been extensively updated. See
703
704 http://www.python.org/2.2/descrintro.html
705
706 That remains the primary documentation in this area.
707
Guido van Rossum33bab012001-12-05 22:45:48 +0000708- Fixed a leak: instance variables declared with __slots__ were never
709 deleted!
710
Guido van Rossum4b800852001-12-03 00:54:52 +0000711- The "delete attribute" method of descriptor objects is called
712 __delete__, not __del__. In previous releases, it was mistakenly
713 called __del__, which created an unfortunate overloading condition
714 with finalizers. (The "get attribute" and "set attribute" methods
715 are still called __get__ and __set__, respectively.)
716
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000717- Some subtle issues with the super built-in were fixed:
718
719 (a) When super itself is subclassed, its __get__ method would still
720 return an instance of the base class (i.e., of super).
721
722 (b) super(C, C()).__class__ would return C rather than super. This
723 is confusing. To fix this, I decided to change the semantics of
724 super so that it only applies to code attributes, not to data
725 attributes. After all, overriding data attributes is not
726 supported anyway.
727
728 (c) The __get__ method didn't check whether the argument was an
729 instance of the type used in creation of the super instance.
730
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000731- Previously, hash() of an instance of a subclass of a mutable type
732 (list or dictionary) would return some value, rather than raising
733 TypeError. This has been fixed. Also, directly calling
734 dict.__hash__ and list.__hash__ now raises the same TypeError
735 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000736
Guido van Rossumd331cb52001-12-05 19:46:42 +0000737- New-style objects now support deleting their __dict__. This is for
738 all intents and purposes equivalent to assigning a brand new empty
739 dictionary, but saves space if the object is not used further.
740
Tim Petersb3c9af12001-11-17 00:21:57 +0000741Core and builtins
742
Tim Peters3caca232001-12-06 06:23:26 +0000743- -Qnew now works as documented in PEP 238: when -Qnew is passed on
744 the command line, all occurrences of "/" use true division instead
745 of classic division. See the PEP for details. Note that "all"
746 means all instances in library and 3rd-party modules, as well as in
747 your own code. As the PEP says, -Qnew is intended for use only in
748 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000749 Note that test_coercion.py in the standard Python test suite fails
750 under -Qnew; this is expected, and won't be repaired until true
751 division becomes the default (in the meantime, test_coercion is
752 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000753
Fred Drake6c01e252001-12-14 17:08:12 +0000754- complex() now only allows the first argument to be a string
755 argument, and raises TypeError if either the second arg is a string
756 or if the second arg is specified when the first is a string.
757
Tim Petersb3c9af12001-11-17 00:21:57 +0000758Extension modules
759
Martin v. Löwis560da622001-11-24 09:24:51 +0000760- gc.get_referents was renamed to gc.get_referrers.
761
Tim Petersb3c9af12001-11-17 00:21:57 +0000762Library
763
Tim Peters25059d32001-12-07 20:35:43 +0000764- Functions in the os.spawn() family now release the global interpreter
765 lock around calling the platform spawn. They should always have done
766 this, but did not before 2.2c1. Multithreaded programs calling
767 an os.spawn function with P_WAIT will no longer block all Python threads
768 until the spawned program completes. It's possible that some programs
769 relies on blocking, although more likely by accident than by design.
770
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000771- webbrowser defaults to netscape.exe on OS/2 now.
772
Martin v. Löwis652e1912001-11-25 14:50:56 +0000773- Tix.ResizeHandle exposes detach_widget, hide, and show.
774
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000775- The charset alias windows_1252 has been added.
776
Barry Warsaw06557452001-12-14 20:47:12 +0000777- types.StringTypes is a tuple containing the defined string types;
778 usually this will be (str, unicode), but if Python was compiled
779 without Unicode support it will be just (str,).
780
781- The pulldom and minidom modules were synchronized to PyXML.
782
Tim Petersb3c9af12001-11-17 00:21:57 +0000783Tools/Demos
784
Barry Warsaw06557452001-12-14 20:47:12 +0000785- A new script called Tools/scripts/google.py was added, which fires
786 off a search on Google.
787
Tim Petersb3c9af12001-11-17 00:21:57 +0000788Build
789
Barry Warsaw06557452001-12-14 20:47:12 +0000790- Note that release builds of Python should arrange to define the
791 preprocessor symbol NDEBUG on the command line (or equivalent).
792 In the 2.2 pre-release series we tried to define this by magic in
793 Python.h instead, but it proved to cause problems for extension
794 authors. The Unix, Windows and Mac builds now all define NDEBUG in
795 release builds via cmdline (or equivalent) instead. Ports to
796 other platforms should do likewise.
797
Jack Jansen1999ef42001-12-06 21:47:20 +0000798- It is no longer necessary to use --with-suffix when building on a
799 case-insensitive file system (such as Mac OS X HFS+). In the build
800 directory an extension is used, but not in the installed python.
801
Tim Petersb3c9af12001-11-17 00:21:57 +0000802C API
803
Tim Petersf582b822001-12-11 18:51:08 +0000804- New function PyDict_MergeFromSeq2() exposes the builtin dict
805 constructor's logic for updating a dictionary from an iterable object
806 producing key-value pairs.
807
Tim Peterscffed4b2001-11-29 03:26:37 +0000808- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000809 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000810 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
811 dump core in some bad cases. This has been repaired. As a result,
812 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
813 previously went unchallenged.
814
Tim Petersb3c9af12001-11-17 00:21:57 +0000815New platforms
816
817Tests
818
819Windows
820
821Mac
822
Jack Jansenffa260f2001-12-06 21:14:00 +0000823- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
824 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000825
Barry Warsaw06557452001-12-14 20:47:12 +0000826- Changed logic for finding python home in Mac OS X framework Pythons.
827 Now sys.executable points to the executable again, in stead of to
828 the shared library. The latter is used only for locating the python
829 home.
830
831
Tim Peters84362bc2001-10-19 17:55:30 +0000832What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000833Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000834===========================
835
836Type/class unification and new-style classes
837
Guido van Rossum3d27df02001-11-15 20:27:54 +0000838- Multiple inheritance mixing new-style and classic classes in the
839 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000840
841 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000842 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000843
844 The MRO (method resolution order) for each base class is respected
845 according to its kind, but the MRO for the derived class is computed
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000846 using new-style MRO rules if any base class is a new-style class.
Tim Peters76f7fe32001-11-15 20:02:21 +0000847 This needs to be documented.
848
Tim Petersa427a2b2001-10-29 22:25:45 +0000849- The new builtin dictionary() constructor, and dictionary type, have
850 been renamed to dict. This reflects a decade of common usage.
851
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000852- dict() now accepts an iterable object producing 2-sequences. For
853 example, dict(d.items()) == d for any dictionary d. The argument,
854 and the elements of the argument, can be any iterable objects.
855
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000856- New-style classes can now have a __del__ method, which is called
857 when the instance is deleted (just like for classic classes).
858
Guido van Rossum12d955c2001-10-26 14:56:06 +0000859- Assignment to object.__dict__ is now possible, for objects that are
860 instances of new-style classes that have a __dict__ (unless the base
861 class forbids it).
862
Guido van Rossumc8e56452001-10-22 00:43:43 +0000863- Methods of built-in types now properly check for keyword arguments
864 (formerly these were silently ignored). The only built-in methods
865 that take keyword arguments are __call__, __init__ and __new__.
866
Guido van Rossum86443212001-10-27 22:28:54 +0000867- The socket function has been converted to a type; see below.
868
Tim Peters84362bc2001-10-19 17:55:30 +0000869Core and builtins
870
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000871- Assignment to __debug__ raises SyntaxError at compile-time. This
872 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000873 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000874
Guido van Rossum12d955c2001-10-26 14:56:06 +0000875- Clarified the error messages for unsupported operands to an operator
876 (like 1 + '').
877
Tim Peters84362bc2001-10-19 17:55:30 +0000878Extension modules
879
Tim Peters5ebfd362001-11-13 23:11:19 +0000880- mmap has a new keyword argument, "access", allowing a uniform way for
881 both Windows and Unix users to create read-only, write-through and
882 copy-on-write memory mappings. This was previously possible only on
883 Unix. A new keyword argument was required to support this in a
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000884 uniform way because the mmap() signatures had diverged across
Tim Peters5ebfd362001-11-13 23:11:19 +0000885 platforms. Thanks to Jay T Miller for repairing this!
886
Tim Peters169ded02001-11-03 19:57:21 +0000887- By default, the gc.garbage list now contains only those instances in
888 unreachable cycles that have __del__ methods; in 2.1 it contained all
889 instances in unreachable cycles. "Instances" here has been generalized
890 to include instances of both new-style and old-style classes.
891
Guido van Rossum12d955c2001-10-26 14:56:06 +0000892- The socket module defines a new method for socket objects,
893 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000894 send() until all data has been sent. Also, the socket function has
895 been converted to a subclassable type, like list and tuple (etc.)
896 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000897
898- Various bugfixes to the curses module. There is now a test suite
899 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000900
Guido van Rossum692adf12001-10-30 03:03:03 +0000901- binascii.b2a_base64 no longer places an arbitrary restriction of 57
902 bytes on its input.
903
Tim Peters84362bc2001-10-19 17:55:30 +0000904Library
905
Tim Peters5ebfd362001-11-13 23:11:19 +0000906- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000907 convenience function.
908
Tim Peters75335872001-11-03 19:35:43 +0000909- Symbolic group names in regular expressions must be unique. For
910 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
911 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000912 Python 2.2 detects this error at regexp compilation time;
913 previously, the error went undetected, and results were
914 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
915 pattern.subn() methods have been rewritten in C. Also, an
916 experimental function/method finditer() has been added, which works
917 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000918
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000919- Tix exposes more commands through the classes DirSelectBox,
920 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
921 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
922 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
923
Tim Peters98791af2001-10-23 01:59:54 +0000924- Traceback objects are now scanned by cyclic garbage collection, so
925 cycles created by casual use of sys.exc_info() no longer cause
926 permanent memory leaks (provided garbage collection is enabled).
927
Guido van Rossum49192142001-10-24 20:51:44 +0000928- os.extsep -- a new variable needed by the RISCOS support. It is the
929 separator used by extensions, and is '.' on all platforms except
930 RISCOS, where it is '/'. There is no need to use this variable
931 unless you have a masochistic desire to port your code to RISCOS.
932
Barry Warsaw012852b2001-11-16 16:17:27 +0000933- mimetypes.py has optional support for non-standard, but commonly
934 found types. guess_type() and guess_extension() now accept an
935 optional `strict' flag, defaulting to true, which controls whether
936 recognize non-standard types or not. A few non-standard types we
937 know about have been added. Also, when run as a script, there are
938 new -l and -e options.
939
940- statcache is now deprecated.
941
942- email.Utils.formatdate() now produces the preferred RFC 2822 style
943 dates with numeric timezones (it used to produce obsolete dates
944 hard coded to "GMT" timezone). An optional `localtime' flag is
945 added to produce dates in the local timezone, with daylight savings
946 time properly taken into account.
947
948- In pickle and cPickle, instead of masking errors in load() by
949 transforming them into SystemError, we let the original exception
950 propagate out. Also, implement support for __safe_for_unpickling__
951 in pickle, as it already was supported in cPickle.
952
Tim Peters84362bc2001-10-19 17:55:30 +0000953Tools/Demos
954
955Build
956
Barry Warsaw012852b2001-11-16 16:17:27 +0000957- The dbm module is built using libdb1 if available. The bsddb module
958 is built with libdb3 if available.
959
960- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
961
Tim Peters84362bc2001-10-19 17:55:30 +0000962C API
963
Tim Peters1fc240e2001-10-26 05:06:50 +0000964- New function PySequence_Fast_GET_SIZE() returns the size of a non-
965 NULL result from PySequence_Fast(), more quickly than calling
966 PySequence_Size().
967
Barry Warsaw012852b2001-11-16 16:17:27 +0000968- New argument unpacking function PyArg_UnpackTuple() added.
969
970- New functions PyObject_CallFunctionObjArgs() and
971 PyObject_CallMethodObjArgs() have been added to make it more
972 convenient and efficient to call functions and methods from C.
973
974- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
975 possible that this will propagate errors it didn't before.
976
977- New function PyObject_CheckReadBuffer(), which returns true if its
978 argument supports the single-segment readable buffer interface.
979
Tim Peters84362bc2001-10-19 17:55:30 +0000980New platforms
981
Guido van Rossum86443212001-10-27 22:28:54 +0000982- We've finally confirmed that this release builds on HP-UX 11.00,
983 *with* threads, and passes the test suite.
984
Tim Peters7a33d8b2001-11-05 02:51:07 +0000985- Thanks to a series of patches from Michael Muller, Python may build
986 again under OS/2 Visual Age C++.
987
Guido van Rossum49192142001-10-24 20:51:44 +0000988- Updated RISCOS port by Dietmar Schwertberger.
989
Tim Peters84362bc2001-10-19 17:55:30 +0000990Tests
991
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000992- Added a test script for the curses module. It isn't run automatically;
993 regrtest.py must be run with '-u curses' to enable it.
994
Tim Peters84362bc2001-10-19 17:55:30 +0000995Windows
996
Barry Warsaw012852b2001-11-16 16:17:27 +0000997Mac
998
999- PythonScript has been moved to unsupported and is slated to be
1000 removed completely in the next release.
1001
1002- It should now be possible to build applets that work on both OS9 and
1003 OSX.
1004
1005- The core is now linked with CoreServices not Carbon; as a side
1006 result, default 8bit encoding on OSX is now ASCII.
1007
1008- Python should now build on OSX 10.1.1
1009
Tim Peters84362bc2001-10-19 17:55:30 +00001010
Tim Petersabf925f2001-09-28 21:53:42 +00001011What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +00001012Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +00001013===========================
1014
1015Type/class unification and new-style classes
1016
Guido van Rossum687ae002001-10-15 22:03:32 +00001017- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001018 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +00001019 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001020 remains: the __dict__ of a new-style class is a read-only proxy; you
1021 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +00001022 __defined__ attribute of new-style types no longer exists, for lack
1023 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001024 future a __cache__ may be resurrected with a similar function, if I
1025 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +00001026
Tim Peters1c9ca872001-10-04 06:43:12 +00001027- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
1028 always returned None, even when there was a class docstring).
1029
1030- doctest now finds and runs docstrings attached to new-style classes,
1031 class methods, static methods, and properties.
1032
Guido van Rossum9074ef62001-10-16 21:34:49 +00001033Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +00001034
Guido van Rossuma8bcf802001-10-15 15:53:58 +00001035- A very subtle syntactical pitfall in list comprehensions was fixed.
1036 For example: [a+b for a in 'abc', for b in 'def']. The comma in
1037 this example is a mistake. Previously, this would silently let 'a'
1038 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
1039 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
1040 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
1041 Note that [a for a in <singleton>] is a convoluted way to say
1042 [<singleton>] anyway, so it's not like any expressiveness is lost.
1043
Guido van Rossum9074ef62001-10-16 21:34:49 +00001044- getattr(obj, name, default) now only catches AttributeError, as
1045 documented, rather than returning the default value for all
1046 exceptions (which could mask bugs in a __getattr__ hook, for
1047 example).
1048
Fred Drakecb7a6b52001-10-22 18:41:51 +00001049- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +00001050 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001051 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +00001052 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +00001053
Guido van Rossum1c486092001-10-19 02:05:35 +00001054- unicode(obj) now behaves more like str(obj), accepting arbitrary
1055 objects, and calling a __unicode__ method if it exists.
1056 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +00001057 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +00001058
Barry Warsawf6fb1712001-10-19 05:35:40 +00001059- isinstance() now allows any object as the first argument and a
1060 class, a type or something with a __bases__ tuple attribute for the
1061 second argument. The second argument may also be a tuple of a
1062 class, type, or something with __bases__, in which case isinstance()
1063 will return true if the first argument is an instance of any of the
1064 things contained in the second argument tuple. E.g.
1065
1066 isinstance(x, (A, B))
1067
1068 returns true if x is an instance of A or B.
1069
Guido van Rossum9074ef62001-10-16 21:34:49 +00001070Extension modules
1071
1072- thread.start_new_thread() now returns the thread ID (previously None).
1073
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001074- binascii has now two quopri support functions, a2b_qp and b2a_qp.
1075
Guido van Rossumc524d952001-10-19 01:31:59 +00001076- readline now supports setting the startup_hook and the
1077 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +00001078
Guido van Rossumc524d952001-10-19 01:31:59 +00001079- os and posix supports chroot(), setgroups() and unsetenv() where
1080 available. The stat(), fstat(), statvfs() and fstatvfs() functions
1081 now return "pseudo-sequences" -- the various fields can now be
1082 accessed as attributes (e.g. os.stat("/").st_mtime) but for
1083 backwards compatibility they also behave as a fixed-length sequence.
1084 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +00001085 attributes.
1086
1087- time: localtime(), gmtime() and strptime() now return a
1088 pseudo-sequence similar to the os.stat() return value, with
1089 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +00001090
Guido van Rossum9074ef62001-10-16 21:34:49 +00001091- Decompression objects in the zlib module now accept an optional
1092 second parameter to decompress() that specifies the maximum amount
1093 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +00001094
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001095- optional SSL support in the socket module now exports OpenSSL
1096 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
1097 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +00001098 automatically seed its PRNG. Also, the keyfile and certfile
1099 arguments to socket.ssl() are now optional.
1100
1101- posixmodule (and by extension, the os module on POSIX platforms) now
1102 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001103
Guido van Rossum9074ef62001-10-16 21:34:49 +00001104Library
Guido van Rossum3c288632001-10-16 21:13:49 +00001105
Tim Peters7402f792001-10-02 03:53:41 +00001106- doctest now excludes functions and classes not defined by the module
1107 being tested, thanks to Tim Hochberg.
1108
Fred Drakecb7a6b52001-10-22 18:41:51 +00001109- HotShot, a new profiler implemented using a C-based callback, has
1110 been added. This substantially reduces the overhead of profiling,
1111 but it is still quite preliminary. Support modules and
1112 documentation will be added in upcoming releases (before 2.2 final).
1113
Guido van Rossumc4b09b42001-10-04 10:19:00 +00001114- profile now produces correct output in situations where an exception
1115 raised in Python is cleared by C code (e.g. hasattr()). This used
1116 to cause wrong output, including spurious claims of recursive
1117 functions and attribution of time spent to the wrong function.
1118
Tim Peters0a1fc4e2001-10-07 03:12:08 +00001119 The code and documentation for the derived OldProfile and HotProfile
1120 profiling classes was removed. The code hasn't worked for years (if
1121 you tried to use them, they raised exceptions). OldProfile
1122 intended to reproduce the behavior of the profiler Python used more
1123 than 7 years ago, and isn't interesting anymore. HotProfile intended
1124 to provide a faster profiler (but producing less information), and
1125 that's a worthy goal we intend to meet via a different approach (but
1126 without losing information).
1127
Tim Peterscce092d2001-10-09 05:31:56 +00001128- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +00001129 a much better system-specific calibration constant. The constant can
1130 now be specified in an instance constructor, or as a Profile class or
1131 instance variable, instead of by editing profile.py's source code.
1132 Calibration must still be done manually (see the docs for the profile
1133 module).
1134
1135 Note that Profile.calibrate() must be overriden by subclasses.
1136 Improving the accuracy required exploiting detailed knowledge of
1137 profiler internals; the earlier method abstracted away the details
1138 and measured a simplified model instead, but consequently computed
1139 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +00001140
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001141- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +00001142 which indicates whether output is intended for the header 'Q'
1143 encoding.
1144
Guido van Rossuma5343cc2001-10-18 18:02:07 +00001145- The SocketServer.ThreadingMixIn class now closes the request after
1146 finish_request() returns. (Not when it errors out though.)
1147
Barry Warsawf6fb1712001-10-19 05:35:40 +00001148- The nntplib module's NNTP.body() method has grown a `file' argument
1149 to allow saving the message body to a file.
1150
1151- The email package has added a class email.Parser.HeaderParser which
1152 only parses headers and does not recurse into the message's body.
1153 Also, the module/class MIMEAudio has been added for representing
1154 audio data (contributed by Anthony Baxter).
1155
1156- ftplib should be able to handle files > 2GB.
1157
1158- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
1159 ON, and OFF.
1160
Fred Drakecb7a6b52001-10-22 18:41:51 +00001161- xml.dom.minidom NodeList objects now support the length attribute
1162 and item() method as required by the DOM specifications.
1163
Guido van Rossumed554f62001-10-02 23:15:37 +00001164Tools/Demos
1165
1166- Demo/dns was removed. It no longer serves any purpose; a package
1167 derived from it is now maintained by Anthony Baxter, see
1168 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +00001169
Barry Warsawf6fb1712001-10-19 05:35:40 +00001170- The freeze tool has been made more robust, and two new options have
1171 been added: -X and -E.
1172
Tim Petersabf925f2001-09-28 21:53:42 +00001173Build
1174
Barry Warsawf6fb1712001-10-19 05:35:40 +00001175- configure will use CXX in LINKCC if CXX is used to build main() and
1176 the system requires to link a C++ main using the C++ compiler.
1177
Tim Petersabf925f2001-09-28 21:53:42 +00001178C API
1179
Guido van Rossum6c4bce32001-10-18 19:20:25 +00001180- The documentation for the tp_compare slot is updated to require that
1181 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
1182 not correct. This is not yet enforced but will be enforced in
1183 Python 2.3; even later, we may use -2 to indicate errors and +2 for
1184 "NotImplemented". Right now, -1 should be used for an error return.
1185
Tim Petersd38b1c72001-09-30 05:09:37 +00001186- PyLong_AsLongLong() now accepts int (as well as long) arguments.
1187 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
1188 as long) arguments.
1189
Guido van Rossum3c288632001-10-16 21:13:49 +00001190- PyThread_start_new_thread() now returns a long int giving the thread
1191 ID, if one can be calculated; it returns -1 for error, 0 if no
1192 thread ID is calculated (this is an incompatible change, but only
1193 the thread module used this API). This code has only really been
1194 tested on Linux and Windows; other platforms please beware (and
1195 report any bugs or strange behavior).
1196
Guido van Rossum1c486092001-10-19 02:05:35 +00001197- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
1198 input.
1199
Tim Petersabf925f2001-09-28 21:53:42 +00001200New platforms
1201
1202Tests
1203
1204Windows
1205
Tim Peters04cf1d32001-10-09 22:39:40 +00001206- Installer: If you install IDLE, and don't disable file-extension
1207 registration, a new "Edit with IDLE" context (right-click) menu entry
1208 is created for .py and .pyw files.
1209
Tim Peters1ce3cf72001-10-01 17:58:40 +00001210- The signal module now supports SIGBREAK on Windows, thanks to Steven
1211 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
1212 action remains to call Win32 ExitProcess(). This can be changed via
1213 signal.signal(). For example:
1214
1215 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
1216 # (SIGINT) behavior.
1217 import signal
1218 signal.signal(signal.SIGBREAK,
1219 signal.default_int_handler)
1220
1221 try:
1222 while 1:
1223 pass
1224 except KeyboardInterrupt:
1225 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
1226 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
1227 # program without the possibility for any Python-level cleanup).
1228 print "Clean exit"
1229
Tim Petersabf925f2001-09-28 21:53:42 +00001230
Tim Petersb07352e2001-09-08 01:25:47 +00001231What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001232Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +00001233===========================
1234
Guido van Rossum808eea72001-09-25 04:15:41 +00001235Type/class unification and new-style classes
1236
1237- pydoc and inspect are now aware of new-style classes;
1238 e.g. help(list) at the interactive prompt now shows proper
1239 documentation for all operations on list objects.
1240
1241- Applications using Jim Fulton's ExtensionClass module can now safely
1242 be used with Python 2.2. In particular, Zope 2.4.1 now works with
1243 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
1244 examples also work again. It is hoped that Gtk and Boost also work
1245 with 2.2a4 and beyond. (If you can confirm this, please write
1246 webmaster@python.org; if there are still problems, please open a bug
1247 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +00001248
Tim Peters66c1a522001-09-24 21:17:50 +00001249- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001250 These map to read-only attributes 'fget', 'fset', 'fdel', and '__doc__'
Tim Peters66c1a522001-09-24 21:17:50 +00001251 in the constructed property object. fget, fset and fdel weren't
1252 discoverable from Python in 2.2a3. __doc__ is new, and allows to
1253 associate a docstring with a property.
1254
Guido van Rossum808eea72001-09-25 04:15:41 +00001255- Comparison overloading is now more completely implemented. For
1256 example, a str subclass instance can properly be compared to a str
1257 instance, and it can properly overload comparison. Ditto for most
1258 other built-in object types.
1259
1260- The repr() of new-style classes has changed; instead of <type
1261 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
1262 *except* for built-in types, which are still rendered as <type
1263 'Foo'> (to avoid upsetting existing code that might parse or
1264 otherwise rely on repr() of certain type objects).
1265
1266- The repr() of new-style objects is now always <Foo object at XXX>;
1267 previously, it was sometimes <Foo instance at XXX>.
1268
1269- For new-style classes, what was previously called __getattr__ is now
1270 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001271 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +00001272 one in classic classes is defined which is called only if regular
1273 attribute access raises AttributeError; to catch *all* attribute
1274 access, you can use __getattribute__ (for new-style classes). If
1275 both are defined, __getattribute__ is called first, and if it raises
1276 AttributeError, __getattr__ is called.
1277
1278- The __class__ attribute of new-style objects can be assigned to.
1279 The new class must have the same C-level object layout as the old
1280 class.
1281
1282- The builtin file type can be subclassed now. In the usual pattern,
1283 "file" is the name of the builtin type, and file() is a new builtin
1284 constructor, with the same signature as the builtin open() function.
1285 file() is now the preferred way to open a file.
1286
1287- Previously, __new__ would only see sequential arguments passed to
1288 the type in a constructor call; __init__ would see both sequential
1289 and keyword arguments. This made no sense whatsoever any more, so
1290 now both __new__ and __init__ see all arguments.
1291
1292- Previously, hash() applied to an instance of a subclass of str or
1293 unicode always returned 0. This has been repaired.
1294
1295- Previously, an operation on an instance of a subclass of an
1296 immutable type (int, long, float, complex, tuple, str, unicode),
1297 where the subtype didn't override the operation (and so the
1298 operation was handled by the builtin type), could return that
1299 instance instead a value of the base type. For example, if s was of
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001300 a str subclass type, s[:] returned s as-is. Now it returns a str
Guido van Rossum808eea72001-09-25 04:15:41 +00001301 with the same value as s.
1302
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001303- Provisional support for pickling new-style objects has been added.
1304
Guido van Rossum808eea72001-09-25 04:15:41 +00001305Core
1306
Tim Peters2c9aa5e2001-09-23 04:06:05 +00001307- file.writelines() now accepts any iterable object producing strings.
1308
Marc-André Lemburgaefd7662001-09-20 12:59:37 +00001309- PyUnicode_FromEncodedObject() now works very much like
1310 PyObject_Str(obj) in that it tries to use __str__/tp_str
1311 on the object if the object is not a string or buffer. This
1312 makes unicode() behave like str() when applied to non-string/buffer
1313 objects.
1314
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001315- PyFile_WriteObject now passes Unicode objects to the file's write
1316 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +00001317 of a print statement must support Unicode objects, i.e. they must
1318 at least convert them into ASCII strings.
1319
Guido van Rossum624c8af2001-09-18 15:21:04 +00001320- Thread scheduling on Solaris should be improved; it is no longer
1321 necessary to insert a small sleep at the start of a thread in order
1322 to let other runnable threads be scheduled.
1323
Tim Petersb07352e2001-09-08 01:25:47 +00001324Library
1325
Marc-André Lemburgbf990172001-09-27 14:17:33 +00001326- StringIO.StringIO instances and cStringIO.StringIO instances support
1327 read character buffer compatible objects for their .write() methods.
1328 These objects are converted to strings and then handled as such
1329 by the instances.
1330
Barry Warsaw2f600732001-09-24 04:28:10 +00001331- The "email" package has been added. This is basically a port of the
1332 mimelib package <http://sf.net/projects/mimelib> with API changes
1333 and some implementations updated to use iterators and generators.
1334
Tim Peters8a9c2842001-09-22 21:30:22 +00001335- difflib.ndiff() and difflib.Differ.compare() are generators now. This
1336 restores the ability of Tools/scripts/ndiff.py to start producing output
1337 before the entire comparison is complete.
1338
Barry Warsaw58b072d2001-09-22 04:44:21 +00001339- StringIO.StringIO instances and cStringIO.StringIO instances support
1340 iteration just like file objects (i.e. their .readline() method is
1341 called for each iteration until it returns an empty string).
1342
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +00001343- The codecs module has grown four new helper APIs to access
1344 builtin codecs: getencoder(), getdecoder(), getreader(),
1345 getwriter().
1346
Guido van Rossum624c8af2001-09-18 15:21:04 +00001347- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
1348 simplifies writing XML RPC servers.
1349
Barry Warsaw647d5e82001-09-28 17:01:02 +00001350- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +00001351 after interpretation of symbolic links. On non-Unix systems, this
1352 is an alias for os.path.abspath().
1353
Tim Peters16a77ad2001-09-08 04:00:12 +00001354- operator.indexOf() (PySequence_Index() in the C API) now works with any
1355 iterable object.
1356
Guido van Rossum624c8af2001-09-18 15:21:04 +00001357- smtplib now supports various authentication and security features of
1358 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001359
Guido van Rossum624c8af2001-09-18 15:21:04 +00001360- hmac: a new module implementing keyed hashing for message
1361 authentication.
1362
1363- mimetypes now recognizes more extensions and file types. At the
1364 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001365
Guido van Rossum624c8af2001-09-18 15:21:04 +00001366- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001367 Python 2.2 bytecode generation. It has also been promoted from a
1368 Tool to a standard library package. (Tools/compiler still exists as
1369 a sample driver.)
1370
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001371Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +00001372
Tim Petersb07352e2001-09-08 01:25:47 +00001373Build
1374
Guido van Rossum624c8af2001-09-18 15:21:04 +00001375- Large file support (LFS) is now automatic when the platform supports
1376 it; no more manual configuration tweaks are needed. On Linux, at
1377 least, it's possible to have a system whose C library supports large
1378 files but whose kernel doesn't; in this case, large file support is
1379 still enabled but doesn't do you any good unless you upgrade your
1380 kernel or share your Python executable with another system whose
1381 kernel has large file support.
1382
1383- The configure script now supplies plausible defaults in a
1384 cross-compilation environment. This doesn't mean that the supplied
1385 values are always correct, or that cross-compilation now works
1386 flawlessly -- but it's a first step (and it shuts up most of
1387 autoconf's warnings about AC_TRY_RUN).
1388
1389- The Unix build is now a bit less chatty, courtesy of the parser
1390 generator. The build is completely silent (except for errors) when
1391 using "make -s", thanks to a -q option to setup.py.
1392
Tim Petersb07352e2001-09-08 01:25:47 +00001393C API
1394
Guido van Rossum624c8af2001-09-18 15:21:04 +00001395- The "structmember" API now supports some new flag bits to deny read
1396 and/or write access to attributes in restricted execution mode.
1397
Tim Petersb07352e2001-09-08 01:25:47 +00001398New platforms
1399
Guido van Rossum624c8af2001-09-18 15:21:04 +00001400- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1401 (http://familiar.handhelds.org).
1402
Tim Petersb07352e2001-09-08 01:25:47 +00001403Tests
1404
Tim Peters8a9c2842001-09-22 21:30:22 +00001405- The "classic" standard tests, which work by comparing stdout to
1406 an expected-output file under Lib/test/output/, no longer stop at
1407 the first mismatch. Instead the test is run to completion, and a
1408 variant of ndiff-style comparison is used to report all differences.
1409 This is much easier to understand than the previous style of reporting.
1410
1411- The unittest-based standard tests now use regrtest's test_main()
1412 convention, instead of running as a side-effect of merely being
1413 imported. This allows these tests to be run in more natural and
1414 flexible ways as unittests, outside the regrtest framework.
1415
1416- regrtest.py is much better integrated with unittest and doctest now,
1417 especially in regard to reporting errors.
1418
Tim Petersb07352e2001-09-08 01:25:47 +00001419Windows
1420
Guido van Rossum624c8af2001-09-18 15:21:04 +00001421- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001422 that support it (NTFS under Windows 2000). See "What's New in
1423 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001424
Tim Petersb07352e2001-09-08 01:25:47 +00001425
Tim Petersedc99312001-08-22 21:36:50 +00001426What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001427Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001428===========================
1429
1430Core
1431
Tim Peters9fffa3e2001-09-04 05:14:19 +00001432- Conversion of long to float now raises OverflowError if the long is too
1433 big to represent as a C double.
1434
Tim Peters32f453e2001-09-03 08:35:41 +00001435- The 3-argument builtin pow() no longer allows a third non-None argument
1436 if either of the first two arguments is a float, or if both are of
1437 integer types and the second argument is negative (in which latter case
1438 the arguments are converted to float, so this is really the same
1439 restriction).
1440
Tim Peters5d2b77c2001-09-03 05:47:38 +00001441- The builtin dir() now returns more information, and sometimes much
1442 more, generally naming all attributes of an object, and all attributes
1443 reachable from the object via its class, and from its class's base
1444 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1445 an empty list. In 2.2a3,
1446
1447 >>> dir([])
1448 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1449 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1450 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1451 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1452 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1453 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1454 'reverse', 'sort']
1455
1456 dir(module) continues to return only the module's attributes, though.
1457
Tim Petersbdee63f2001-09-02 03:40:59 +00001458- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001459 than raising OverflowError. This is a partial implementation of PEP
1460 237. You can use -Wdefault::OverflowWarning to enable a warning for
1461 this situation, and -Werror::OverflowWarning to revert to the old
1462 OverflowError exception.
1463
Guido van Rossum61c345f2001-09-04 03:26:15 +00001464- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001465 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001466 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1467 -Qold, meaning the / operator has its classic meaning and no
1468 warnings are issued. Using -Qwarn issues a run-time warning about
1469 all uses of classic division for int and long arguments; -Qwarnall
1470 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001471 (for use with fixdiv.py).
1472 [Note: the remainder of this paragraph (preserved below) became
1473 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1474 <obsolete>
1475 Using -Qnew is questionable; it turns on new division by default, but
1476 only in the __main__ module. You can usefully combine -Qwarn or
1477 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1478 warns about classic division everywhere else.
1479 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001480
Tim Petersbdee63f2001-09-02 03:40:59 +00001481- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001482 long, float, str, unicode, and tuple. (The types complex, list and
1483 dictionary can also be subclassed; this was introduced earlier.)
1484 Note that restrictions apply when subclassing immutable built-in
1485 types: you can only affect the value of the instance by overloading
1486 __new__. You can add mutable attributes, and the subclass instances
1487 will have a __dict__ attribute, but you cannot change the "value"
1488 (as implemented by the base class) of an immutable subclass instance
1489 once it is created.
1490
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001491- The dictionary constructor now takes an optional argument, a
1492 mapping-like object, and initializes the dictionary from its
1493 (key, value) pairs.
1494
Tim Petersbdee63f2001-09-02 03:40:59 +00001495- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001496 "cooperative super calls" in a multiple inheritance setting. For an
1497 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1498
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001499- A new built-in type, property, has been added. This enables the
1500 creation of "properties". These are attributes implemented by
1501 getter and setter functions (or only one of these for read-only or
1502 write-only attributes), without the need to override __getattr__.
1503 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001504
Tim Petersbdee63f2001-09-02 03:40:59 +00001505- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001506 liberalized, to allow leading zeroes. Examples of literals now
1507 legal that were SyntaxErrors before:
1508
1509 00.0 0e3 0100j 07.5 00000000000000000008.
1510
Tim Petersbdee63f2001-09-02 03:40:59 +00001511- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001512 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1513
Tim Petersedc99312001-08-22 21:36:50 +00001514Library
1515
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001516- telnetlib includes symbolic names for the options, and support for
1517 setting an option negotiation callback.
1518
Tim Petersa40c7932001-09-05 22:36:56 +00001519- The new C standard no longer requires that math libraries set errno to
1520 ERANGE on overflow. For platform libraries that exploit this new
1521 freedom, Python's overflow-checking was wholly broken. A new overflow-
1522 checking scheme attempts to repair that, but may not be reliable on all
1523 platforms (C doesn't seem to provide anything both useful and portable
1524 in this area anymore).
1525
Martin v. Löwis44f86962001-09-05 13:44:54 +00001526- Asynchronous timeout actions are available through the new class
1527 threading.Timer.
1528
Tim Peters78526162001-09-05 00:53:45 +00001529- math.log and math.log10 now return sensible results for even huge
1530 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1531
Tim Petersbdee63f2001-09-02 03:40:59 +00001532- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001533 currently held. See the docs for the imp module.
1534
Tim Petersbdee63f2001-09-02 03:40:59 +00001535- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001536 dumps containing ints written on platforms where Python ints are 8 bytes.
1537 When read on a box where Python ints are 4 bytes, such values are
1538 converted to Python longs.
1539
Tim Petersbdee63f2001-09-02 03:40:59 +00001540- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001541 code objects is no longer allowed. This plugs a security hole.
1542
Steve Purcell6091cd62001-09-06 16:05:17 +00001543- unittest.TestResult instances no longer store references to tracebacks
1544 generated by test failures. This prevents unexpected dangling references
1545 to objects that should be garbage collected between tests.
1546
Tim Petersedc99312001-08-22 21:36:50 +00001547Tools
1548
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001549- Tools/scripts/fixdiv.py has been added which can be used to fix
1550 division operators as per PEP 238.
1551
Tim Petersedc99312001-08-22 21:36:50 +00001552Build
1553
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001554- If you are an adventurous person using Mac OS X you may want to look at
1555 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1556 application, which can be used for experimenting with Carbon or Cocoa.
1557 Discussion of this on pythonmac-sig, please.
1558
Tim Peters7eea37e2001-09-04 22:08:56 +00001559C API
1560
1561- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001562
Tim Peters9fffa3e2001-09-04 05:14:19 +00001563- Note that PyLong_AsDouble can fail! This has always been true, but no
1564 callers checked for it. It's more likely to fail now, because overflow
1565 errors are properly detected now. The proper way to check:
1566
1567 double x = PyLong_AsDouble(some_long_object);
1568 if (x == -1.0 && PyErr_Occurred()) {
1569 /* The conversion failed. */
1570 }
1571
Tim Petersbdee63f2001-09-02 03:40:59 +00001572- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001573 compile but will not participate in GC. To upgrade an extension
1574 module:
1575
1576 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001577
Neil Schemenauer4042c692001-08-30 15:38:01 +00001578 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1579 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001580
Neil Schemenauer4042c692001-08-30 15:38:01 +00001581 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1582 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001583
Neil Schemenauer4042c692001-08-30 15:38:01 +00001584 - remove PyGC_HEAD_SIZE from object size calculations
1585
1586 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1587
Tim Petersbdee63f2001-09-02 03:40:59 +00001588- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001589 These can be used safely to construct string objects from a
1590 sprintf-style format string (similar to the format string supported
1591 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001592
Tim Petersedc99312001-08-22 21:36:50 +00001593New platforms
1594
Tim Petersb7da0902001-09-02 23:01:43 +00001595- Stephen Hansen contributed patches sufficient to get a clean compile
1596 under Borland C (Windows), but he reports problems running it and ran
1597 out of time to complete the port. Volunteers? Expect a MemoryError
1598 when importing the types module; this is probably shallow, and
1599 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001600
Tim Petersedc99312001-08-22 21:36:50 +00001601Tests
1602
1603Windows
1604
Tim Peters6e13a562001-09-06 00:32:15 +00001605- Large file support is now enabled on Win32 platforms as well as on
1606 Win64. This means that, for example, you can use f.tell() and f.seek()
1607 to manipulate files larger than 2 gigabytes (provided you have enough
1608 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001609 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1610 filesize limit, and large file support makes no difference there.
1611 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1612 NTFS has no practical limit on file size, and files of any size can be
1613 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001614
Tim Petersbdee63f2001-09-02 03:40:59 +00001615- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001616 points to command.com (patch from Brian Quinlan).
1617
Tim Petersedc99312001-08-22 21:36:50 +00001618
Tim Peters20f51a72001-07-21 02:31:40 +00001619What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001620Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001621===========================
1622
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001623Build
1624
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001625- Tim Peters developed a brand new Windows installer using Wise 8.1,
1626 generously donated to us by Wise Solutions.
1627
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001628- configure supports a new option --enable-unicode, with the values
1629 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1630 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001631
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001632- A new configure option --enable-framework builds a Mac OS X framework,
1633 which "make frameworkinstall" will install. This provides a starting
1634 point for more mac-like functionality, join pythonmac-sig@python.org
1635 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001636
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001637- The NeXT platform is no longer supported.
1638
1639- The `new' module is now statically linked.
1640
Tim Peters0afb6092001-08-15 06:06:44 +00001641Tools
1642
1643- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001644 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001645 the module docstring for details.
1646
Tim Peters20f51a72001-07-21 02:31:40 +00001647Tests
1648
Tim Peters5e824c32001-08-12 22:25:01 +00001649- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001650 platforms, allowing to give clearer test result output. regrtest
1651 also has optional --use/-u switch to run normally disabled tests
1652 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001653
Tim Peters20f51a72001-07-21 02:31:40 +00001654- Several new tests in the standard test suite, with special thanks to
1655 Nick Mathewson.
1656
1657Core
1658
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001659- The floor division operator // has been added as outlined in PEP
1660 238. The / operator still provides classic division (and will until
1661 Python 3.0) unless "from __future__ import division" is included, in
1662 which case the / operator will provide true division. The operator
1663 module provides truediv() and floordiv() functions. Augmented
1664 assignment variants are included, as are the equivalent overloadable
1665 methods and C API methods. See the PEP for a full discussion:
1666 <http://python.sf.net/peps/pep-0238.html>
1667
Tim Peters6cd6a822001-08-17 22:11:27 +00001668- Future statements are now effective in simulated interactive shells
1669 (like IDLE). This should "just work" by magic, but read Michael
1670 Hudson's "Future statements in simulated shells" PEP 264 for full
1671 details: <http://python.sf.net/peps/pep-0264.html>.
1672
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001673- The type/class unification (PEP 252-253) was integrated into the
1674 trunk and is not so tentative any more (the exact specification of
1675 some features is still tentative). A lot of work has done on fixing
1676 bugs and adding robustness and features (performance still has to
1677 come a long way).
1678
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001679- Warnings about a mismatch in the Python API during extension import
1680 now use the Python warning framework (which makes it possible to
1681 write filters for these warnings).
1682
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001683- A function's __dict__ (aka func_dict) will now always be a
1684 dictionary. It used to be possible to delete it or set it to None,
1685 but now both actions raise TypeErrors. It is still legal to set it
1686 to a dictionary object. Getting func.__dict__ before any attributes
1687 have been assigned now returns an empty dictionary instead of None.
1688
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001689- A new command line option, -E, was added which disables the use of
1690 all environment variables, or at least those that are specifically
1691 significant to Python. Usually those have a name starting with
1692 "PYTHON". This was used to fix a problem where the tests fail if
1693 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1694 older distribution.
1695
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001696Library
1697
Tim Peters5e824c32001-08-12 22:25:01 +00001698- New class Differ and new functions ndiff() and restore() in difflib.py.
1699 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001700 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001701
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001702- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1703 value using the minimal quoting required for the value; more
1704 reliable than using xml.sax.saxutils.escape() for attribute values.
1705
1706- Readline completion support for cmd.Cmd was added.
1707
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001708- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1709
1710- Added function threading.BoundedSemaphore()
1711
1712- Added Ka-Ping Yee's cgitb.py module.
1713
1714- The `new' module now exposes the CO_xxx flags.
1715
Martin v. Löwis560da622001-11-24 09:24:51 +00001716- The gc module offers the get_referents function.
1717
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001718New platforms
1719
1720C API
1721
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001722- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1723 which provide a cross-platform implementations for the
1724 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1725 the standard sprintf() and vsprintf() C lib APIs, these versions
1726 apply bounds checking on the used buffer which enhances protection
1727 against buffer overruns.
1728
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001729- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001730 and extensions using different Unicode widths is rendered next to
1731 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001732 will result in an ImportError. Unicode extensions writers must make
1733 sure to check the Unicode width compatibility in their extensions by
1734 using at least one of the mangled Unicode APIs in the extension.
1735
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001736- Two new flags METH_NOARGS and METH_O are available in method definition
1737 tables to simplify implementation of methods with no arguments and a
1738 single untyped argument. Calling such methods is more efficient than
1739 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1740 deprecated.
1741
Tim Petersc1731372001-08-04 08:12:36 +00001742Windows
1743
1744- "import module" now compiles module.pyw if it exists and nothing else
1745 relevant is found.
1746
Tim Peters20f51a72001-07-21 02:31:40 +00001747
Guido van Rossum55a78992001-07-17 17:22:32 +00001748What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001749Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001750===========================
1751
1752Core
Tim Petersa814db52001-05-14 07:05:58 +00001753
Tim Peters6d6c1a32001-08-02 04:15:00 +00001754- TENTATIVELY, a large amount of code implementing much of what's
1755 described in PEP 252 (Making Types Look More Like Classes) and PEP
1756 253 (Subtyping Built-in Types) was added. This will be released
1757 with Python 2.2a1. Documentation will be provided separately
1758 through http://www.python.org/2.2/. The purpose of releasing this
1759 with Python 2.2a1 is to test backwards compatibility. It is
1760 possible, though not likely, that a decision is made not to release
1761 this code as part of 2.2 final, if any serious backwards
1762 incompapatibilities are found during alpha testing that cannot be
1763 repaired.
1764
Guido van Rossum55a78992001-07-17 17:22:32 +00001765- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001766 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001767 more 'yield' statements. See PEP 255. Since this adds a new
1768 keyword to the language, this feature must be enabled by including a
1769 future statement: "from __future__ import generators" (see PEP 236).
1770 Generators will become a standard feature in a future release
1771 (probably 2.3). Without this future statement, 'yield' remains an
1772 ordinary identifier, but a warning is issued each time it is used.
1773 (These warnings currently don't conform to the warnings framework of
1774 PEP 230; we intend to fix this in 2.2a2.)
1775
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001776- The UTF-16 codec was modified to be more RFC compliant. It will now
1777 only remove BOM characters at the start of the string and then
1778 only if running in native mode (UTF-16-LE and -BE won't remove a
1779 leading BMO character).
1780
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001781- Strings now have a new method .decode() to complement the already
1782 existing .encode() method. These two methods provide direct access
1783 to the corresponding decoders and encoders of the registered codecs.
1784
1785 To enhance the usability of the .encode() method, the special
1786 casing of Unicode object return values was dropped (Unicode objects
1787 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001788
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001789 Both methods will now return whatever the codec in charge of the
1790 requested encoding returns as object, e.g. Unicode codecs will
1791 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1792 will return u"äöü"). This enables codec writer to create codecs
1793 for various simple to use conversions.
1794
1795 New codecs were added to demonstrate these new features (the .encode()
1796 and .decode() columns indicate the type of the returned objects):
1797
1798 Name | .encode() | .decode() | Description
1799 ----------------------------------------------------------------------
1800 uu | string | string | UU codec (e.g. for email)
1801 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001802 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001803 zlib | string | string | zlib compression
1804 hex | string | string | 2-byte hex codec
1805 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1806
Mark Hammond2a0af792001-05-14 03:09:36 +00001807- Some operating systems now support the concept of a default Unicode
1808 encoding for file system operations. Notably, Windows supports 'mbcs'
1809 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001810 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001811 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001812
1813 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001814 functions that return filenames (such as os.listdir()) to return Python
1815 string objects pre-encoded using the default file system encoding for
1816 the platform. As this encoding is likely to be different from Python's
1817 default encoding, converting this name to a Unicode object before passing
1818 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001819 would attempt to use its default encoding (generally ASCII) rather than
1820 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001821
Tim Petersa814db52001-05-14 07:05:58 +00001822 In general, this change simply removes surprises when working with
1823 Unicode and the file system, making these operations work as you expect,
1824 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001825 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001826
Tim Peters61dff2b2001-05-08 15:43:37 +00001827- Float (and complex) literals in source code were evaluated to full
1828 precision only when running from a .py file; the same code loaded from a
1829 .pyc (or .pyo) file could suffer numeric differences starting at about the
1830 12th significant decimal digit. For example, on a machine with IEEE-754
1831 floating arithmetic,
1832
1833 x = 9007199254740992.0
1834 print long(x)
1835
1836 printed 9007199254740992 if run directly from .py, but 9007199254740000
1837 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1838 str(float) instead of repr(float) when building code objects. marshal
1839 now uses repr(float) instead, which should reproduce floats to full
1840 machine precision (assuming the platform C float<->string I/O conversion
1841 functions are of good quality).
1842
1843 This may cause floating-point results to change in some cases, and
1844 usually for the better, but may also cause numerically unstable
1845 algorithms to break.
1846
Tim Peters2f228e72001-05-13 00:19:31 +00001847- The implementation of dicts suffers fewer collisions, which has speed
1848 benefits. However, the order in which dict entries appear in dict.keys(),
1849 dict.values() and dict.items() may differ from previous releases for a
1850 given dict. Nothing is defined about this order, so no program should
1851 rely on it. Nevertheless, it's easy to write test cases that rely on the
1852 order by accident, typically because of printing the str() or repr() of a
1853 dict to an "expected results" file. See Lib/test/test_support.py's new
1854 sortdict(dict) function for a simple way to display a dict in sorted
1855 order.
1856
Tim Peters7a3bfc32001-06-12 01:22:22 +00001857- Many other small changes to dicts were made, resulting in faster
1858 operation along the most common code paths.
1859
Guido van Rossum10315822001-05-01 20:54:30 +00001860- Dictionary objects now support the "in" operator: "x in dict" means
1861 the same as dict.has_key(x).
1862
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001863- The update() method of dictionaries now accepts generic mapping
1864 objects. Specifically the argument object must support the .keys()
1865 and __getitem__() methods. This allows you to say, for example,
1866 {}.update(UserDict())
1867
Guido van Rossum10315822001-05-01 20:54:30 +00001868- Iterators were added; this is a generalized way of providing values
1869 to a for loop. See PEP 234. There's a new built-in function iter()
1870 to return an iterator. There's a new protocol to get the next value
1871 from an iterator using the next() method (in Python) or the
1872 tp_iternext slot (in C). There's a new protocol to get iterators
1873 using the __iter__() method (in Python) or the tp_iter slot (in C).
1874 Iterating (i.e. a for loop) over a dictionary generates its keys.
1875 Iterating over a file generates its lines.
1876
Tim Petersf553f892001-05-01 20:45:31 +00001877- The following functions were generalized to work nicely with iterator
1878 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001879 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001880 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1881 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001882 join() method of strings
1883 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001884 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1885 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001886 right-hand side of assignment statements with multiple targets, such as
1887 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001888
Tim Petersd85e1022001-05-11 21:51:48 +00001889- Accessing module attributes is significantly faster (for example,
1890 random.random or os.path or yourPythonModule.yourAttribute).
1891
Tim Peterse63415e2001-05-08 04:38:29 +00001892- Comparing dictionary objects via == and != is faster, and now works even
1893 if the keys and values don't support comparisons other than ==.
1894
Tim Peters95bf9392001-05-10 08:32:44 +00001895- Comparing dictionaries in ways other than == and != is slower: there were
1896 insecurities in the dict comparison implementation that could cause Python
1897 to crash if the element comparison routines for the dict keys and/or
1898 values mutated the dicts. Making the code bulletproof slowed it down.
1899
Tim Peterseb28ef22001-06-02 05:27:19 +00001900- Collisions in dicts are resolved via a new approach, which can help
1901 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001902 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001903 faster now. Thanks to Christian Tismer for pointing out the cause and
1904 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001905
Tim Peters52e155e2001-06-16 05:42:57 +00001906- repr() is much faster for large containers (dict, list, tuple).
1907
1908
Tim Petersa814db52001-05-14 07:05:58 +00001909Library
1910
Fred Drake960fdf92001-07-20 18:38:26 +00001911- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1912 were added to the string module. These a locale-indenpendent
1913 constants, unlike letters, lowercase, and uppercase. These are now
1914 use in appropriate locations in the standard library.
1915
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001916- The flags used in dlopen calls can now be configured using
1917 sys.setdlopenflags and queried using sys.getdlopenflags.
1918
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001919- Fredrik Lundh's xmlrpclib is now a standard library module. This
1920 provides full client-side XML-RPC support. In addition,
1921 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1922 one asyncore-based). Thanks to Eric Raymond for the documentation.
1923
Guido van Rossum643d3912001-07-05 14:46:25 +00001924- The xrange() object is simplified: it no longer supports slicing,
1925 repetition, comparisons, efficient 'in' checking, the tolist()
1926 method, or the start, stop and step attributes. See PEP 260.
1927
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001928- A new function fnmatch.filter to filter lists of file names was added.
1929
Barry Warsawffd674d2001-05-22 16:00:10 +00001930- calendar.py uses month and day names based on the current locale.
1931
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001932- strop is now *really* obsolete (this was announced before with 1.6),
1933 and issues DeprecationWarning when used (except for the four items
1934 that are still imported into string.py).
1935
Tim Petersa814db52001-05-14 07:05:58 +00001936- Cookie.py now sorts key+value pairs by key in output strings.
1937
1938- pprint.isrecursive(object) didn't correctly identify recursive objects.
1939 Now it does.
1940
Tim Peters95b3f782001-05-14 18:39:41 +00001941- pprint functions now much faster for large containers (tuple, list, dict).
1942
Tim Peters7b9542a2001-06-10 23:40:19 +00001943- New 'q' and 'Q' format codes in the struct module, corresponding to C
1944 types "long long" and "unsigned long long" (on Windows, __int64). In
1945 native mode, these can be used only when the platform C compiler supports
1946 these types (when HAVE_LONG_LONG is #define'd by the Python config
1947 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001948 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1949 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001950
Guido van Rossum83213cc2001-06-12 16:48:52 +00001951- The site module installs a new built-in function 'help' that invokes
1952 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1953 it displays a message reminding the user to use 'help()' or
1954 'help(object)'.
1955
Tim Petersa814db52001-05-14 07:05:58 +00001956Tests
1957
1958- New test_mutants.py runs dict comparisons where the key and value
1959 comparison operators mutute the dicts randomly during comparison. This
1960 rapidly causes Python to crash under earlier releases (not for the faint
1961 of heart: it can also cause Win9x to freeze or reboot!).
1962
1963- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001964 pprint.isreadable() return sensible results. Also verifies that simple
1965 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001966
Tim Peters4324aa32001-05-28 22:30:08 +00001967C API
1968
1969- Removed the unused last_is_sticky argument from the internal
1970 _PyTuple_Resize(). If this affects you, you were cheating.
1971
1972
Guido van Rossum55a78992001-07-17 17:22:32 +00001973======================================================================
1974
1975
Guido van Rossumffe13be2001-04-16 18:46:45 +00001976What's New in Python 2.1 (final)?
1977=================================
1978
1979We only changed a few things since the last release candidate, all in
1980Python library code:
1981
1982- A bug in the locale module was fixed that affected locales which
1983 define no grouping for numeric formatting.
1984
1985- A few bugs in the weakref module's implementations of weak
1986 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1987 and the test suite was updated to check for these bugs.
1988
1989- An old bug in the os.path.walk() function (introduced in Python
1990 2.0!) was fixed: a non-existent file would cause an exception
1991 instead of being ignored.
1992
1993- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1994 PyChecker.
1995
1996
Guido van Rossum5b08f132001-04-16 02:05:23 +00001997What's New in Python 2.1c2?
1998===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001999
Guido van Rossum5b08f132001-04-16 02:05:23 +00002000A flurry of small changes, and one showstopper fixed in the nick of
2001time made it necessary to release another release candidate. The list
2002here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00002003
Guido van Rossum5b08f132001-04-16 02:05:23 +00002004Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00002005
Guido van Rossum5b08f132001-04-16 02:05:23 +00002006- Tim discovered a nasty bug in the dictionary code, caused by
2007 PyDict_Next() calling dict_resize(), and the GC code's use of
2008 PyDict_Next() violating an assumption in dict_items(). This was
2009 fixed with considerable amounts of band-aid, but the net effect is a
2010 saner and more robust implementation.
2011
2012- Made a bunch of symbols static that were accidentally global.
2013
2014Build and Ports
2015
2016- The setup.py script didn't check for a new enough version of zlib
2017 (1.1.3 is needed). Now it does.
2018
2019- Changed "make clean" target to also remove shared libraries.
2020
2021- Added a more general warning about the SGI Irix optimizer to README.
2022
2023Library
2024
2025- Fix a bug in urllib.basejoin("http://host", "../file.html") which
2026 omitted the slash between host and file.html.
2027
2028- The mailbox module's _Mailbox class contained a completely broken
2029 and undocumented seek() method. Ripped it out.
2030
2031- Fixed a bunch of typos in various library modules (urllib2, smtpd,
2032 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
2033
2034- Fixed a few last-minute bugs in unittest.
2035
2036Extensions
2037
2038- Reverted the patch to the OpenSSL code in socketmodule.c to support
2039 RAND_status() and the EGD, and the subsequent patch that tried to
2040 fix it for pre-0.9.5 versions; the problem with the patch is that on
2041 some systems it issues a warning whenever socket is imported, and
2042 that's unacceptable.
2043
2044Tests
2045
2046- Fixed the pickle tests to work with "import test.test_pickle".
2047
2048- Tweaked test_locale.py to actually run the test Windows.
2049
2050- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
2051 not "wb" (which is not a valid mode at all).
2052
2053- Fix pstats browser crashes. Import readline if it exists to make
2054 the user interface nicer.
2055
2056- Add "import thread" to the top of test modules that import the
2057 threading module (test_asynchat and test_threadedtempfile). This
2058 prevents test failures caused by a broken threading module resulting
2059 from a previously caught failed import.
2060
2061- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
2062 needed on some platforms (e.g. Solaris 8) when the tests are run
2063 twice in succession.
2064
2065- Skip rather than fail test_sunaudiodev if no audio device is found.
2066
2067
2068What's New in Python 2.1c1?
2069===========================
2070
2071This list was significantly updated when 2.1c2 was released; the 2.1c1
2072release didn't mention most changes that were actually part of 2.1c1:
2073
2074Legal
2075
2076- Copyright was assigned to the Python Software Foundation (PSF) and a
2077 PSF license (very similar to the CNRI license) was added.
2078
2079- The CNRI copyright notice was updated to include 2001.
2080
2081Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00002082
Guido van Rossumc9932722001-04-12 02:31:27 +00002083- After a public outcry, assignment to __debug__ is no longer illegal;
2084 instead, a warning is issued. It will become illegal in 2.2.
2085
Guido van Rossum5b08f132001-04-16 02:05:23 +00002086- Fixed a core dump with "%#x" % 0, and changed the semantics so that
2087 "%#x" now always prepends "0x", even if the value is zero.
2088
2089- Fixed some nits in the bytecode compiler.
2090
2091- Fixed core dumps when calling certain kinds of non-functions.
2092
2093- Fixed various core dumps caused by reference count bugs.
2094
2095Build and Ports
2096
2097- Use INSTALL_SCRIPT to install script files.
2098
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002099- New port: SCO Unixware 7, by Billy G. Allie.
2100
Guido van Rossum5b08f132001-04-16 02:05:23 +00002101- Updated RISCOS port.
2102
2103- Updated BeOS port and notes.
2104
2105- Various other porting problems resolved.
2106
2107Library
2108
2109- The TERMIOS and SOCKET modules are now truly obsolete and
2110 unnecessary. Their symbols are incorporated in the termios and
2111 socket modules.
2112
2113- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
2114 better tests for pickling.
2115
2116- threading: make Condition.wait() robust against KeyboardInterrupt.
2117
2118- zipfile: add support to zipfile to support opening an archive
2119 represented by an open file rather than a file name. Fix bug where
2120 the archive was not properly closed. Fixed a bug in this bugfix
2121 where flush() was called for a read-only file.
2122
2123- imputil: added an uninstall() method to the ImportManager.
2124
2125- Canvas: fixed bugs in lower() and tkraise() methods.
2126
2127- SocketServer: API change (added overridable close_request() method)
2128 so that the TCP server can explicitly close the request.
2129
2130- pstats: Eric Raymond added a simple interactive statistics browser,
2131 invoked when the module is run as a script.
2132
2133- locale: fixed a problem in format().
2134
2135- webbrowser: made it work when the BROWSER environment variable has a
2136 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
2137 KDE 2. Fixed some other nits.
2138
2139- unittest: changes to allow using a different exception than
2140 AssertionError, and added a few more function aliases. Some other
2141 small changes.
2142
2143- urllib, urllib2: fixed redirect problems and a coupleof other nits.
2144
2145- asynchat: fixed a critical bug in asynchat that slipped through the
2146 2.1b2 release. Fixed another rare bug.
2147
2148- Fix some unqualified except: clauses (always a bad code example).
2149
2150XML
2151
2152- pyexpat: new API get_version_string().
2153
2154- Fixed some minidom bugs.
2155
2156Extensions
2157
2158- Fixed a core dump in _weakref. Removed the weakref.mapping()
2159 function (it adds nothing to the API).
2160
2161- Rationalized the use of header files in the readline module, to make
2162 it compile (albeit with some warnings) with the very recent readline
2163 4.2, without breaking for earlier versions.
2164
2165- Hopefully fixed a buffering problem in linuxaudiodev.
2166
2167- Attempted a fix to make the OpenSSL support in the socket module
2168 work again with pre-0.9.5 versions of OpenSSL.
2169
2170Tests
2171
2172- Added a test case for asynchat and asyncore.
2173
2174- Removed coupling between tests where one test failing could break
2175 another.
2176
2177Tools
2178
2179- Ping added an interactive help browser to pydoc, fixed some nits
2180 in the rest of the pydoc code, and added some features to his
2181 inspect module.
2182
2183- An updated python-mode.el version 4.1 which integrates Ken
2184 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
2185 much nicer in XEmacs and Emacs. When stepping through your program
2186 with pdb, in either the shell window or the *Python* window, the
2187 source file and line will be tracked by an arrow. Very cool!
2188
2189- IDLE: syntax warnings in interactive mode are changed into errors.
2190
2191- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00002192 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00002193
2194- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002195
Barry Warsaw11e89c72001-04-11 20:37:57 +00002196
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002197What's New in Python 2.1 beta 2?
2198================================
2199
Guido van Rossum053ae352001-03-22 14:17:21 +00002200(Unlisted are many fixed bugs, more documentation, etc.)
2201
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002202Core language, builtins, and interpreter
2203
Guido van Rossum053ae352001-03-22 14:17:21 +00002204- The nested scopes work (enabled by "from __future__ import
2205 nested_scopes") is completed; in particular, the future now extends
2206 into code executed through exec, eval() and execfile(), and into the
2207 interactive interpreter.
2208
2209- When calling a base class method (e.g. BaseClass.__init__(self)),
2210 this is now allowed even if self is not strictly spoken a class
2211 instance (e.g. when using metaclasses or the Don Beaudry hook).
2212
2213- Slice objects are now comparable but not hashable; this prevents
2214 dict[:] from being accepted but meaningless.
2215
2216- Complex division is now calculated using less braindead algorithms.
2217 This doesn't change semantics except it's more likely to give useful
2218 results in extreme cases. Complex repr() now uses full precision
2219 like float repr().
2220
2221- sgmllib.py now calls handle_decl() for simple <!...> declarations.
2222
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002223- It is illegal to assign to the name __debug__, which is set when the
2224 interpreter starts. It is effectively a compile-time constant.
2225
2226- A warning will be issued if a global statement for a variable
2227 follows a use or assignment of that variable.
2228
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002229Standard library
2230
Guido van Rossum053ae352001-03-22 14:17:21 +00002231- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
2232 inspired by JUnit), is now part of the standard library. You now
2233 have a choice of two testing frameworks: unittest requires you to
2234 write testcases as separate code, doctest gathers them from
2235 docstrings. Both approaches have their advantages and
2236 disadvantages.
2237
2238- A new module Tix was added, which wraps the Tix extension library
2239 for Tk. With that module, it is not necessary to statically link
2240 Tix with _tkinter, since Tix will be loaded with Tcl's "package
2241 require" command. See Demo/tix/.
2242
2243- tzparse.py is now obsolete.
2244
2245- In gzip.py, the seek() and tell() methods are removed -- they were
2246 non-functional anyway, and it's better if callers can test for their
2247 existence with hasattr().
2248
2249Python/C API
2250
2251- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
2252 that's already in the dictionary during a PyDict_Next() iteration.
2253 This used to fail occasionally when a dictionary resize operation
2254 could be triggered that would rehash all the keys. All other
2255 modifications to the dictionary are still off-limits during a
2256 PyDict_Next() iteration!
2257
2258- New extended APIs related to passing compiler variables around.
2259
2260- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
2261 implement isinstance() and issubclass().
2262
2263- Py_BuildValue() now has a "D" conversion to create a Python complex
2264 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002265
Fred Drake4e262a92001-03-22 18:26:47 +00002266- Extensions types which support weak references must now set the
2267 field allocated for the weak reference machinery to NULL themselves;
2268 this is done to avoid the cost of checking each object for having a
2269 weakly referencable type in PyObject_INIT(), since most types are
2270 not weakly referencable.
2271
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002272- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
2273 free variables and cell variables to and from the frame's f_locals.
2274
2275- Variants of several functions defined in pythonrun.h have been added
2276 to support the nested_scopes future statement. The variants all end
2277 in Flags and take an extra argument, a PyCompilerFlags *; examples:
2278 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
2279 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00002280 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002281
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002282Distutils
2283
2284- the sdist command now writes a PKG-INFO file, as described in PEP 241,
2285 into the release tree.
2286
Tim Peters0e57abf2001-05-02 07:39:38 +00002287- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002288 (an uninstaller, more customization of the installer's display)
2289
2290- from Jack Jansen: added Mac-specific code to generate a dialog for
2291 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00002292 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002293 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00002294
2295- added 'platforms' and 'keywords' to the set of metadata that can be
2296 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002297
2298- applied patches from Jason Tishler to make the compiler class work with
2299 Cygwin.
2300
2301
Tim Peters2fe289a2001-03-01 22:19:38 +00002302What's New in Python 2.1 beta 1?
2303================================
Tim Petersd66595f2001-02-04 03:09:53 +00002304
2305Core language, builtins, and interpreter
2306
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00002307- Following an outcry from the community about the amount of code
2308 broken by the nested scopes feature introduced in 2.1a2, we decided
2309 to make this feature optional, and to wait until Python 2.2 (or at
2310 least 6 months) to make it standard. The option can be enabled on a
2311 per-module basis by adding "from __future__ import nested_scopes" at
2312 the beginning of a module (before any other statements, but after
2313 comments and an optional docstring). See PEP 236 (Back to the
2314 __future__) for a description of the __future__ statement. PEP 227
2315 (Statically Nested Scopes) has been updated to reflect this change,
2316 and to clarify the semantics in a number of endcases.
2317
2318- The nested scopes code, when enabled, has been hardened, and most
2319 bugs and memory leaks in it have been fixed.
2320
2321- Compile-time warnings are now generated for a number of conditions
2322 that will break or change in meaning when nested scopes are enabled:
2323
2324 - Using "from...import *" or "exec" without in-clause in a function
2325 scope that also defines a lambda or nested function with one or
2326 more free (non-local) variables. The presence of the import* or
2327 bare exec makes it impossible for the compiler to determine the
2328 exact set of local variables in the outer scope, which makes it
2329 impossible to determine the bindings for free variables in the
2330 inner scope. To avoid the warning about import *, change it into
2331 an import of explicitly name object, or move the import* statement
2332 to the global scope; to avoid the warning about bare exec, use
2333 exec...in... (a good idea anyway -- there's a possibility that
2334 bare exec will be deprecated in the future).
2335
2336 - Use of a global variable in a nested scope with the same name as a
2337 local variable in a surrounding scope. This will change in
2338 meaning with nested scopes: the name in the inner scope will
2339 reference the variable in the outer scope rather than the global
2340 of the same name. To avoid the warning, either rename the outer
2341 variable, or use a global statement in the inner function.
2342
Neil Schemenauera35c6882001-02-27 04:45:05 +00002343- An optional object allocator has been included. This allocator is
2344 optimized for Python objects and should be faster and use less memory
2345 than the standard system allocator. It is not enabled by default
2346 because of possible thread safety problems. The allocator is only
2347 protected by the Python interpreter lock and it is possible that some
2348 extension modules require a thread safe allocator. The object
2349 allocator can be enabled by providing the "--with-pymalloc" option to
2350 configure.
2351
Tim Petersd66595f2001-02-04 03:09:53 +00002352Standard library
2353
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002354- pyexpat now detects the expat version if expat.h defines it. A
2355 number of additional handlers are provided, which are only available
2356 since expat 1.95. In addition, the methods SetParamEntityParsing and
2357 GetInputContext of Parser objects are available with 1.95.x
2358 only. Parser objects now provide the ordered_attributes and
2359 specified_attributes attributes. A new module expat.model was added,
2360 which offers a number of additional constants if 1.95.x is used.
2361
2362- xml.dom offers the new functions registerDOMImplementation and
2363 getDOMImplementation.
2364
2365- xml.dom.minidom offers a toprettyxml method. A number of DOM
2366 conformance issues have been resolved. In particular, Element now
2367 has an hasAttributes method, and the handling of namespaces was
2368 improved.
2369
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002370- Ka-Ping Yee contributed two new modules: inspect.py, a module for
2371 getting information about live Python code, and pydoc.py, a module
2372 for interactively converting docstrings to HTML or text.
2373 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002374 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002375 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2376 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002377
Tim Peters1eff7962001-03-01 02:31:33 +00002378- New library module difflib.py, primarily packaging the SequenceMatcher
2379 class at the heart of the popular ndiff.py file-comparison tool.
2380
2381- doctest.py (a framework for verifying Python code examples in docstrings)
2382 is now part of the std library.
2383
Tim Petersd66595f2001-02-04 03:09:53 +00002384Windows changes
2385
Guido van Rossume3955a82001-03-02 14:05:59 +00002386- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2387 small GUI that lets you browse the module docstrings using your
2388 default web browser.
2389
Tim Peters1eff7962001-03-01 02:31:33 +00002390- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2391 Platforms) is implemented. See
2392
2393 http://python.sourceforge.net/peps/pep-0235.html
2394
2395 for full details, especially the "Current Lower-Left Semantics" section.
2396 The new Windows import rules are simpler than before:
2397
2398 A. If the PYTHONCASEOK environment variable exists, same as
2399 before: silently accept the first case-insensitive match of any
2400 kind; raise ImportError if none found.
2401
2402 B. Else search sys.path for the first case-sensitive match; raise
2403 ImportError if none found.
2404
2405 The same rules have been implented on other platforms with case-
2406 insensitive but case-preserving filesystems too (including Cygwin, and
2407 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002408
Tim Peters25a9ce32001-02-19 07:06:36 +00002409- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2410 what it's supposed to do (and does do under NT and 2000) via direct
2411 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002412 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002413 all Win9x systems before.
2414
Tim Peters1eff7962001-03-01 02:31:33 +00002415- Build: Subproject _test (effectively) renamed to _testcapi.
2416
Tim Peters2fe289a2001-03-01 22:19:38 +00002417New platforms
2418
2419- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2420 Thanks to Steven Majewski!
2421
2422- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2423 Tishler!
2424
Guido van Rossum9089b272001-03-02 06:49:50 +00002425- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2426 Schwertberger! See RISCOS/README for more information -- it seems
2427 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002428 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002429
Tim Peters25a9ce32001-02-19 07:06:36 +00002430
Tim Petersd7b5e882001-01-25 03:36:26 +00002431What's New in Python 2.1 alpha 2?
2432=================================
Tim Peters40ead762001-01-27 05:35:26 +00002433
Tim Petersd7b5e882001-01-25 03:36:26 +00002434Core language, builtins, and interpreter
2435
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002436- Scopes nest. If a name is used in a function or class, but is not
2437 local, the definition in the nearest enclosing function scope will
2438 be used. One consequence of this change is that lambda statements
2439 could reference variables in the namespaces where the lambda is
2440 defined. In some unusual cases, this change will break code.
2441
2442 In all previous version of Python, names were resolved in exactly
2443 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002444 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002445 function A is defined within a function B, the names bound in B are
2446 not visible in A. The new rules make names bound in B visible in A,
2447 unless A contains a name binding that hides the binding in B.
2448
2449 Section 4.1 of the reference manual describes the new scoping rules
2450 in detail. The test script in Lib/test/test_scope.py demonstrates
2451 some of the effects of the change.
2452
2453 The new rules will cause existing code to break if it defines nested
2454 functions where an outer function has local variables with the same
2455 name as globals or builtins used by the inner function. Example:
2456
2457 def munge(str):
2458 def helper(x):
2459 return str(x)
2460 if type(str) != type(''):
2461 str = helper(str)
2462 return str.strip()
2463
2464 Under the old rules, the name str in helper() is bound to the
2465 builtin function str(). Under the new rules, it will be bound to
2466 the argument named str and an error will occur when helper() is
2467 called.
2468
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002469- The compiler will report a SyntaxError if "from ... import *" occurs
2470 in a function or class scope. The language reference has documented
2471 that this case is illegal, but the compiler never checked for it.
2472 The recent introduction of nested scope makes the meaning of this
2473 form of name binding ambiguous. In a future release, the compiler
2474 may allow this form when there is no possibility of ambiguity.
2475
Tim Peters40ead762001-01-27 05:35:26 +00002476- repr(string) is easier to read, now using hex escapes instead of octal,
2477 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2478
2479 >>> "\texample \r\n" + chr(0) + chr(255)
2480 '\texample \r\n\x00\xff' # in 2.1
2481 '\011example \015\012\000\377' # in 2.0
2482
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002483- Functions are now compared and hashed by identity, not by value, since
2484 the func_code attribute is writable.
2485
Fred Drakefb9d7122001-02-01 20:00:40 +00002486- Weak references (PEP 205) have been added. This involves a few
2487 changes in the core, an extension module (_weakref), and a Python
2488 module (weakref). The weakref module is the public interface. It
2489 includes support for "explicit" weak references, proxy objects, and
2490 mappings with weakly held values.
2491
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002492- A 'continue' statement can now appear in a try block within the body
2493 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002494 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002495
Tim Petersd7b5e882001-01-25 03:36:26 +00002496Standard library
2497
Barry Warsaw30dbd142001-01-31 22:14:01 +00002498- mailbox.py now has a new class, PortableUnixMailbox which is
2499 identical to UnixMailbox but uses a more portable scheme for
2500 determining From_ separators. Also, the constructors for all the
2501 classes in this module have a new optional `factory' argument, which
2502 is a callable used when new message classes must be instantiated by
2503 the next() method.
2504
Tim Petersd7b5e882001-01-25 03:36:26 +00002505- random.py is now self-contained, and offers all the functionality of
2506 the now-deprecated whrandom.py. See the docs for details. random.py
2507 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002508 and restoring the internal state of the generator; and jumpahead(n),
2509 for quickly forcing the internal state to be the same as if n calls to
2510 random() had been made. The latter is particularly useful for multi-
2511 threaded programs, creating one instance of the random.Random() class for
2512 each thread, then using .jumpahead() to force each instance to use a
2513 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002514
Tim Peters0de88fc2001-02-01 04:59:18 +00002515- random.py's seed() function is new. For bit-for-bit compatibility with
2516 prior releases, use the whseed function instead. The new seed function
2517 addresses two problems: (1) The old function couldn't produce more than
2518 about 2**24 distinct internal states; the new one about 2**45 (the best
2519 that can be done in the Wichmann-Hill generator). (2) The old function
2520 sometimes produced identical internal states when passed distinct
2521 integers, and there was no simple way to predict when that would happen;
2522 the new one guarantees to produce distinct internal states for all
2523 arguments in [0, 27814431486576L).
2524
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002525- The socket module now supports raw packets on Linux. The socket
2526 family is AF_PACKET.
2527
Tim Peters9ea17ac2001-02-02 05:57:15 +00002528- test_capi.py is a start at running tests of the Python C API. The tests
2529 are implemented by the new Modules/_testmodule.c.
2530
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002531- A new extension module, _symtable, provides provisional access to the
2532 internal symbol table used by the Python compiler. A higher-level
2533 interface will be added on top of _symtable in a future release.
2534
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002535- Removed the obsolete soundex module.
2536
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002537- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2538 the isSameNode method; NamedNodeMap the get method.
2539
2540- xml.sax.expatreader supports the lexical handler property; it
2541 generates comment, startCDATA, and endCDATA events.
2542
Tim Petersee826f82001-01-31 19:39:44 +00002543Windows changes
2544
2545- Build procedure: the zlib project is built in a different way that
2546 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002547 the zlib binary used. See PCbuild\readme.txt for details. Your old
2548 zlib-related directories can be deleted; you'll need to download fresh
2549 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002550
Tim Peters9ea17ac2001-02-02 05:57:15 +00002551- Build: New subproject _test for the benefit of test_capi.py (see above).
2552
Tim Petersb16c56f2001-02-02 21:24:51 +00002553- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2554 interface to some Python compiler internals).
2555
2556- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002557 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002558
Tim Petersa3a3a032000-11-30 05:22:44 +00002559What's New in Python 2.1 alpha 1?
2560=================================
2561
2562Core language, builtins, and interpreter
2563
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002564- There is a new Unicode companion to the PyObject_Str() API
2565 called PyObject_Unicode(). It behaves in the same way as the
2566 former, but assures that the returned value is an Unicode object
2567 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002568
Guido van Rossumf98eda02001-01-17 15:54:45 +00002569- The comparison operators support "rich comparison overloading" (PEP
2570 207). C extension types can provide a rich comparison function in
2571 the new tp_richcompare slot in the type object. The cmp() function
2572 and the C function PyObject_Compare() first try the new rich
2573 comparison operators before trying the old 3-way comparison. There
2574 is also a new C API PyObject_RichCompare() (which also falls back on
2575 the old 3-way comparison, but does not constrain the outcome of the
2576 rich comparison to a Boolean result).
2577
2578 The rich comparison function takes two objects (at least one of
2579 which is guaranteed to have the type that provided the function) and
2580 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2581 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2582 object, which may be NotImplemented (in which case the tp_compare
2583 slot function is used as a fallback, if defined).
2584
2585 Classes can overload individual comparison operators by defining one
2586 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002587 __ge__. There are no explicit "reflected argument" versions of
2588 these; instead, __lt__ and __gt__ are each other's reflection,
2589 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2590 reflection (similar at the C level). No other implications are
2591 made; in particular, Python does not assume that == is the Boolean
2592 inverse of !=, or that < is the Boolean inverse of >=. This makes
2593 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002594
2595 Classes or types that want to implement (in)equality tests but not
2596 the ordering operators (i.e. unordered types) should implement ==
2597 and !=, and raise an error for the ordering operators.
2598
Guido van Rossuma88479f2001-01-18 14:28:08 +00002599 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002600 Boolean; e.g. a matrix type might want to return a matrix of bits
2601 for A < B, giving elementwise comparisons. Such types should ensure
2602 that any interpretation of their value in a Boolean context raises
2603 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2604 at the C level) to always raise an exception.
2605
Guido van Rossuma88479f2001-01-18 14:28:08 +00002606- Complex numbers use rich comparisons to define == and != but raise
2607 an exception for <, <=, > and >=. Unfortunately, this also means
2608 that cmp() of two complex numbers raises an exception when the two
2609 numbers differ. Since it is not mathematically meaningful to compare
2610 complex numbers except for equality, I hope that this doesn't break
2611 too much code.
2612
Tim Peters3389f192001-02-18 08:48:49 +00002613- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002614 not defined by the language, other than that it's arbitrary but
2615 consistent (see the Reference Manual). An implementation detail changed
2616 in 2.1a1 such that None now compares less than any other object. Code
2617 relying on this new behavior (like code that relied on the previous
2618 behavior) does so at its own risk.
2619
Barry Warsaw573b5412001-01-15 20:43:18 +00002620- Functions and methods now support getting and setting arbitrarily
2621 named attributes (PEP 232). Functions have a new __dict__
2622 (a.k.a. func_dict) which hold the function attributes. Methods get
2623 and set attributes on their underlying im_func. It is a TypeError
2624 to set an attribute on a bound method.
2625
Guido van Rossum051e3352001-01-15 19:11:10 +00002626- The xrange() object implementation has been improved so that
2627 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2628 limitation that in this case len(xrange(sys.maxint)) can't be
2629 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2630 work fine as long as the index i doesn't actually reach 2**31.
2631 (Python uses regular ints for sequence and string indices; fixing
2632 that is much more work.)
2633
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002634- Two changes to from...import:
2635
Guido van Rossumba381232001-02-03 15:06:40 +00002636 1) "from M import X" now works even if (after loading module M)
2637 sys.modules['M'] is not a real module; it's basically a getattr()
2638 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002639
2640 2) "from M import *" now looks for M.__all__ to decide which names to
2641 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2642 filters out names starting with '_' as before. Whether or not
2643 __all__ exists, there's no restriction on the type of M.
2644
Guido van Rossumf61f1662001-01-10 20:13:55 +00002645- File objects have a new method, xreadlines(). This is the fastest
2646 way to iterate over all lines in a file:
2647
2648 for line in file.xreadlines():
2649 ...do something to line...
2650
2651 See the xreadlines module (mentioned below) for how to do this for
2652 other file-like objects.
2653
2654- Even if you don't use file.xreadlines(), you may expect a speedup on
2655 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002656 quite a bit in platform-specific ways: on systems (like Linux) that
2657 support flockfile(), getc_unlocked(), and funlockfile(), those are
2658 used by default. On systems (like Windows) without getc_unlocked(),
2659 a complicated (but still thread-safe) method using fgets() is used by
2660 default.
2661
Tim Petersd52269b2001-01-25 06:23:18 +00002662 You can force use of the fgets() method by #define'ing
2663 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002664 getc_unlocked()).
2665
Tim Petersd52269b2001-01-25 06:23:18 +00002666 You can force fgets() not to be used by #define'ing
2667 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002668 test_bufio.py fails -- and let us know if it does!).
2669
2670- In addition, the fileinput module, while still slower than the other
2671 methods on most platforms, has been sped up too, by using
2672 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002673
2674- Support for run-time warnings has been added, including a new
2675 command line option (-W) to specify the disposition of warnings.
2676 See the description of the warnings module below.
2677
2678- Extensive changes have been made to the coercion code. This mostly
2679 affects extension modules (which can now implement mixed-type
2680 numerical operators without having to use coercion), but
2681 occasionally, in boundary cases the coercion semantics have changed
2682 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002683 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002684 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002685 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002686
Guido van Rossumf98eda02001-01-17 15:54:45 +00002687- In connection with the coercion changes, a new built-in singleton
2688 object, NotImplemented is defined. This can be returned for
2689 operations that wish to indicate they are not implemented for a
2690 particular combination of arguments. From C, this is
2691 Py_NotImplemented.
2692
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002693- The interpreter accepts now bytecode files on the command line even
2694 if they do not have a .pyc or .pyo extension. On Linux, after executing
2695
Martin v. Löwise214baa2001-02-04 22:37:56 +00002696import imp,sys,string
2697magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2698reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2699open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002700
2701 any byte code file can be used as an executable (i.e. as an argument
2702 to execve(2)).
2703
Tim Peters9940b802000-12-01 07:59:35 +00002704- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002705 character. In 1.6 and earlier, they never produced a sign,
2706 and raised an error if the value of the long was too large
2707 to fit in a Python int. In 2.0, they produced a sign if and
2708 only if too large to fit in an int. This was inconsistent
2709 across platforms (because the size of an int varies across
2710 platforms), and inconsistent with hex() and oct(). Example:
2711
2712 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002713 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002714 'ffffffbe' # in 2.0 and before, on 32-bit machines
2715 >>> hex(-0x42L)
2716 '-0x42L' # in all versions of Python
2717
Tim Peters9940b802000-12-01 07:59:35 +00002718 The behavior of %d formats for negative Python longs remains
2719 the same as in 2.0 (although in 1.6 and before, they raised
2720 an error if the long didn't fit in a Python int).
2721
2722 %u formats don't make sense for Python longs, but are allowed
2723 and treated the same as %d in 2.1. In 2.0, a negative long
2724 formatted via %u produced a sign if and only if too large to
2725 fit in an int. In 1.6 and earlier, a negative long formatted
2726 via %u raised an error if it was too big to fit in an int.
2727
Guido van Rossum3661d392000-12-12 22:10:31 +00002728- Dictionary objects have an odd new method, popitem(). This removes
2729 an arbitrary item from the dictionary and returns it (in the form of
2730 a (key, value) pair). This can be useful for algorithms that use a
2731 dictionary as a bag of "to do" items and repeatedly need to pick one
2732 item. Such algorithms normally end up running in quadratic time;
2733 using popitem() they can usually be made to run in linear time.
2734
Tim Peters36cdad12000-12-29 02:06:45 +00002735Standard library
2736
Thomas Woutersfe385252001-01-19 23:16:56 +00002737- In the time module, the time argument to the functions strftime,
2738 localtime, gmtime, asctime and ctime is now optional, defaulting to
2739 the current time (in the local timezone).
2740
Guido van Rossumda91f222001-01-15 16:36:08 +00002741- The ftplib module now defaults to passive mode, which is deemed a
2742 more useful default given that clients are often inside firewalls
2743 these days. Note that this could break if ftplib is used to connect
2744 to a *server* that is inside a firewall, from outside; this is
2745 expected to be a very rare situation. To fix that, you can call
2746 ftp.set_pasv(0).
2747
Martin v. Löwis10a27872001-01-13 09:54:41 +00002748- The module site now treats .pth files not only for path configuration,
2749 but also supports extensions to the initialization code: Lines starting
2750 with import are executed.
2751
Guido van Rossumf61f1662001-01-10 20:13:55 +00002752- There's a new module, warnings, which implements a mechanism for
2753 issuing and filtering warnings. There are some new built-in
2754 exceptions that serve as warning categories, and a new command line
2755 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2756 turns warnings into errors). warnings.warn(message[, category])
2757 issues a warning message; this can also be called from C as
2758 PyErr_Warn(category, message).
2759
2760- A new module xreadlines was added. This exports a single factory
2761 function, xreadlines(). The intention is that this code is the
2762 absolutely fastest way to iterate over all lines in an open
2763 file(-like) object:
2764
2765 import xreadlines
2766 for line in xreadlines.xreadlines(file):
2767 ...do something to line...
2768
2769 This is equivalent to the previous the speed record holder using
2770 file.readlines(sizehint). Note that if file is a real file object
2771 (as opposed to a file-like object), this is equivalent:
2772
2773 for line in file.xreadlines():
2774 ...do something to line...
2775
Tim Peters36cdad12000-12-29 02:06:45 +00002776- The bisect module has new functions bisect_left, insort_left,
2777 bisect_right and insort_right. The old names bisect and insort
2778 are now aliases for bisect_right and insort_right. XXX_right
2779 and XXX_left methods differ in what happens when the new element
2780 compares equal to one or more elements already in the list: the
2781 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002782 right. Code that doesn't care where equal elements end up should
2783 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002784
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002785- The new curses.panel module wraps the panel library that forms part
2786 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2787
Guido van Rossumf61f1662001-01-10 20:13:55 +00002788- The SocketServer module now sets the allow_reuse_address flag by
2789 default in the TCPServer class.
2790
2791- A new function, sys._getframe(), returns the stack frame pointer of
2792 the caller. This is intended only as a building block for
2793 higher-level mechanisms such as string interpolation.
2794
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002795- The pyexpat module supports a number of new handlers, which are
2796 available only in expat 1.2. If invocation of a callback fails, it
2797 will report an additional frame in the traceback. Parser objects
2798 participate now in garbage collection. If expat reports an unknown
2799 encoding, pyexpat will try to use a Python codec; that works only
2800 for single-byte charsets. The parser type objects is exposed as
2801 XMLParserObject.
2802
2803- xml.dom now offers standard definitions for symbolic node type and
2804 exception code constants, and a hierarchy of DOM exceptions. minidom
2805 was adjusted to use them.
2806
2807- The conformance of xml.dom.minidom to the DOM specification was
2808 improved. It detects a number of additional error cases; the
2809 previous/next relationship works even when the tree is modified;
2810 Node supports the normalize() method; NamedNodeMap, DocumentType and
2811 DOMImplementation classes were added; Element supports the
2812 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2813 method.
2814
Guido van Rossumf61f1662001-01-10 20:13:55 +00002815Build issues
2816
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002817- For Unix (and Unix-compatible) builds, configuration and building of
2818 extension modules is now greatly automated. Rather than having to
2819 edit the Modules/Setup file to indicate which modules should be
2820 built and where their include files and libraries are, a
2821 distutils-based setup.py script now takes care of building most
2822 extension modules. All extension modules built this way are built
2823 as shared libraries. Only a few modules that must be linked
2824 statically are still listed in the Setup file; you won't need to
2825 edit their configuration.
2826
2827- Python should now build out of the box on Cygwin. If it doesn't,
2828 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002829
2830- Python now always uses its own (renamed) implementation of getopt()
2831 -- there's too much variation among C library getopt()
2832 implementations.
2833
2834- C++ compilers are better supported; the CXX macro is always set to a
2835 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002836
Tim Petersd92dfe02000-12-12 01:18:41 +00002837Windows changes
2838
2839- select module: By default under Windows, a select() call
2840 can specify no more than 64 sockets. Python now boosts
2841 this Microsoft default to 512. If you need even more than
2842 that, see the MS docs (you'll need to #define FD_SETSIZE
2843 and recompile Python from source).
2844
Guido van Rossumf61f1662001-01-10 20:13:55 +00002845- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2846 subdirectory is no more!
2847
Tim Petersa3a3a032000-11-30 05:22:44 +00002848
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002849What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002850=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002851
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002852Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002853changes are in the file HISTORY. If you are making the jump directly
2854from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2855HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002856
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002857Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2858the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2859http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002860
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002861--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002862
2863======================================================================
2864
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002865What's new in 2.0 (since release candidate 1)?
2866==============================================
2867
2868Standard library
2869
2870- The copy_reg module was modified to clarify its intended use: to
2871 register pickle support for extension types, not for classes.
2872 pickle() will raise a TypeError if it is passed a class.
2873
2874- Fixed a bug in gettext's "normalize and expand" code that prevented
2875 it from finding an existing .mo file.
2876
2877- Restored support for HTTP/0.9 servers in httplib.
2878
Tim Peters989b7b92000-10-16 20:24:53 +00002879- The math module was changed to stop raising OverflowError in case of
2880 underflow, and return 0 instead in underflow cases. Whether Python
2881 used to raise OverflowError in case of underflow was platform-
2882 dependent (it did when the platform math library set errno to ERANGE
2883 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002884
2885- Fixed a bug in StringIO that occurred when the file position was not
2886 at the end of the file and write() was called with enough data to
2887 extend past the end of the file.
2888
2889- Fixed a bug that caused Tkinter error messages to get lost on
2890 Windows. The bug was fixed by replacing direct use of
2891 interp->result with Tcl_GetStringResult(interp).
2892
2893- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2894 redirect response.
2895
2896- Several changes were made to distutils: Some debugging code was
2897 removed from util. Fixed the installer used when an external zip
2898 program (like WinZip) is not found; the source code for this
2899 installer is in Misc/distutils. check_lib() was modified to behave
2900 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2901 test for whether installed modules are on sys.path was changed to
2902 use both normcase() and normpath().
2903
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002904- Several minor bugs were fixed in the xml package (the minidom,
2905 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002906
2907- The regression test driver (regrtest.py) behavior when invoked with
2908 -l changed: It now reports a count of objects that are recognized as
2909 garbage but not freed by the garbage collector.
2910
Tim Peters989b7b92000-10-16 20:24:53 +00002911- The regression test for the math module was changed to test
2912 exceptional behavior when the test is run in verbose mode. Python
2913 cannot yet guarantee consistent exception behavior across platforms,
2914 so the exception part of test_math is run only in verbose mode, and
2915 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002916
2917Internals
2918
2919- PyOS_CheckStack() has been disabled on Win64, where it caused
2920 test_sre to fail.
2921
2922Build issues
2923
2924- Changed compiler flags, so that gcc is always invoked with -Wall and
2925 -Wstrict-prototypes. Users compiling Python with GCC should see
2926 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002927 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002928 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002929
Tim Petersa3a3a032000-11-30 05:22:44 +00002930- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002931
2932Tools and other miscellany
2933
2934- The compiler in Tools/compiler was updated to support the new
2935 language features introduced in 2.0: extended print statement, list
2936 comprehensions, and augmented assignments. The new compiler should
2937 also be backwards compatible with Python 1.5.2; the compiler will
2938 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002939 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002940
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002941What's new in 2.0 release candidate 1 (since beta 2)?
2942=====================================================
2943
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002944What is release candidate 1?
2945
2946We believe that release candidate 1 will fix all known bugs that we
2947intend to fix for the 2.0 final release. This release should be a bit
2948more stable than the previous betas. We would like to see even more
2949widespread testing before the final release, so we are producing this
2950release candidate. The final release will be exactly the same unless
2951any show-stopping (or brown bag) bugs are found by testers of the
2952release candidate.
2953
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002954All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002955to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002956
2957Core language, builtins, and interpreter
2958
2959- A bug that caused crashes when __coerce__ was used with augmented
2960 assignment, e.g. +=, was fixed.
2961
2962- Raise ZeroDivisionError when raising zero to a negative number,
2963 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2964 power operator and the result of math.pow(0.0, -2.0) will vary by
2965 platform. On Linux, it raises a ValueError.
2966
2967- A bug in Unicode string interpolation was fixed that occasionally
2968 caused errors with formats including "%%". For example, the
2969 following expression "%% %s" % u"abc" no longer raises a TypeError.
2970
2971- Compilation of deeply nested expressions raises MemoryError instead
2972 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2973
2974- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2975 rendering them useless. They are now written in binary mode again.
2976
2977Standard library
2978
2979- Keyword arguments are now accepted for most pattern and match object
2980 methods in SRE, the standard regular expression engine.
2981
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002982- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002983 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002984
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002985- Several bugs in the Unicode handling and error handling in _tkinter
2986 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002987
2988- Fix memory management errors in Merge() and Tkapp_Call() routines.
2989
2990- Several changes were made to cStringIO to make it compatible with
2991 the file-like object interface and with StringIO. If operations are
2992 performed on a closed object, an exception is raised. The truncate
2993 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002994 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002995
2996- There were many changes made to the linuxaudiodev module and its
2997 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002998 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002999
3000 Note that this module is named poorly, because it should work
3001 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00003002 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003003
3004 The module now raises exceptions when errors occur instead of
3005 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
3006 audio) and defines a getptr() method that calls the
3007 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
3008
3009- The library_version attribute, introduced in an earlier beta, was
3010 removed because it can not be supported with early versions of the C
3011 readline library, which provides no way to determine the version at
3012 compile-time.
3013
3014- The binascii module is now enabled on Win64.
3015
Tim Peters46446d62000-10-09 21:19:31 +00003016- tokenize.py no longer suffers "recursion depth" errors when parsing
3017 programs with very long string literals.
3018
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003019Internals
3020
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003021- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003022 which is called when the interpreter starts up to determine where
3023 the standard library is installed. These vulnerabilities affect all
3024 previous versions of Python and can be exploited by setting very
3025 long values for PYTHONHOME or argv[0]. The risk is greatest for a
3026 setuid Python script, although use of the wrapper in
3027 Misc/setuid-prog.c will eliminate the vulnerability.
3028
3029- Fixed garbage collection bugs in instance creation that were
3030 triggered when errors occurred during initialization. The solution,
3031 applied in cPickle and in PyInstance_New(), is to call
3032 PyObject_GC_Init() after the initialization of the object's
3033 container attributes is complete.
3034
3035- pyexpat adds definitions of PyModule_AddStringConstant and
3036 PyModule_AddObject if the Python version is less than 2.0, which
3037 provides compatibility with PyXML on Python 1.5.2.
3038
3039- If the platform has a bogus definition for LONG_BIT (the number of
3040 bits in a long), an error will be reported at compile time.
3041
3042- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
3043 collection crashes and possibly other, unreported crashes.
3044
3045- Fixed a memory leak in _PyUnicode_Fini().
3046
3047Build issues
3048
3049- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003050 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00003051 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003052
3053- The mmap.PAGESIZE constant is now initialized using sysconf when
3054 possible, which eliminates a dependency on -lucb for Reliant UNIX.
3055
3056- The md5 file should now compile on all platforms.
3057
3058- The select module now compiles on platforms that do not define
3059 POLLRDNORM and related constants.
3060
3061- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00003062 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003063
Jeremy Hylton10921202000-10-09 18:34:12 +00003064- BeOS: A number of changes were made to the build and installation
3065 process. ar-fake now operates on a directory of object files.
3066 dl_export.h is gone, and its macros now appear on the mwcc command
3067 line during build on PPC BeOS.
3068
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003069- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00003070 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003071
3072- Cygwin: Support for shared libraries, Tkinter, and sockets.
3073
3074- SunOS 4.1.4_JL: Fix test for directory existence in configure.
3075
3076Tools and other miscellany
3077
3078- Removed debugging prints from main used with freeze.
3079
Tim Peters46446d62000-10-09 21:19:31 +00003080- IDLE auto-indent no longer crashes when it encounters Unicode
3081 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003082
3083What's new in 2.0 beta 2 (since beta 1)?
3084========================================
3085
3086Core language, builtins, and interpreter
3087
Tim Peters482c0212000-09-26 06:33:09 +00003088- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003089 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003090
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003091- Add -h and -V command line options to print the usage message and
3092 Python version number and exit immediately.
3093
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003094- eval() and exec accept Unicode objects as code parameters.
3095
3096- getattr() and setattr() now also accept Unicode objects for the
3097 attribute name, which are converted to strings using the default
3098 encoding before lookup.
3099
3100- Multiplication on string and Unicode now does proper bounds
3101 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
3102 string is too long."
3103
3104- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00003105 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003106
Jeremy Hylton1b618592000-09-26 05:32:36 +00003107
3108Standard library and extensions
3109
Guido van Rossum5b08f132001-04-16 02:05:23 +00003110- socket module: the OpenSSL code now adds support for RAND_status()
3111 and EGD (Entropy Gathering Device).
3112
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003113- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00003114 argument checking; it still takes no arguments.
3115
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003116- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003117
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003118- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003119
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003120- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003121
3122- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003123 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003124
3125- copy: Copy Unicode objects atomically.
3126
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003127- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003128
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003129- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003130
Fred Drake67233bc2000-09-26 16:40:27 +00003131- dbm: Add get() and setdefault() methods to dbm object. Add constant
3132 `library' to module that names the library used. Added doc strings
3133 and method names to error messages. Uses configure to determine
3134 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
3135 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003136
3137- distutils: Update to version 0.9.3.
3138
3139- dl: Add several dl.RTLD_ constants.
3140
3141- fpectl: Now supported on FreeBSD.
3142
3143- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
3144 found by the collector will be saved in gc.garbage. This is useful
3145 for debugging a program that creates reference cycles.
3146
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003147- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00003148 of HTTP class. Do not close socket on zero-length response. Do not
3149 crash when server sends invalid content-length header.
3150
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003151- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003152
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003153- marshal: When reading a short, sign-extend on platforms where shorts
3154 are bigger than 16 bits. When reading a long, repair the unportable
3155 sign extension that was being done for 64-bit machines. (It assumed
3156 that signed right shift sign-extends.)
3157
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003158- operator: Add contains(), invert(), __invert__() as aliases for
3159 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003160
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003161- os: Add support for popen2() and popen3() on all platforms where
3162 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003163
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003164- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00003165 clicking on a file in Explorer (or passing the file name to the
3166 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003167
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003168- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00003169 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003170
3171- pickle: Now raises ValueError when an invalid pickle that contains
3172 a non-string repr where a string repr was expected. This behavior
3173 matches cPickle.
3174
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003175- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003176
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003177- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003178
3179- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003180 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003181 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003182
3183- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003184 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003185
3186- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00003187 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00003188 few cycles during startup since the first call to
3189 setdefaultencoding() will initialize the codec registry and the
3190 encodings package.
3191
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003192- socket: Support for size hint in readlines() method of object returned
3193 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003194
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003195- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00003196 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00003197 is followed by whitespace.
3198
Tim Petersa3a3a032000-11-30 05:22:44 +00003199- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003200
3201- struct: Check ranges for bytes and shorts.
3202
3203- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003204 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003205
3206- Tkinter: Image objects are now guaranteed to have unique ids. Set
3207 event.delta to zero if Tk version doesn't support mousewheel.
3208 Removed some debugging prints.
3209
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003210- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003211
Fred Drake67233bc2000-09-26 16:40:27 +00003212- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003213 which works around a bug in Norton AntiVirus 2000 that leads directly
3214 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003215
3216- xml: New version detection code allows PyXML to override standard
3217 XML package if PyXML version is greater than 0.6.1.
3218
Fred Drake64bb3802000-09-26 16:21:35 +00003219- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
3220 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
3221 tree only for nodes which are sufficiently interesting to a specific
3222 application. Does not provide the HTML-specific extensions. Still
3223 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003224
Fred Drake64bb3802000-09-26 16:21:35 +00003225- xml.sax: SAX 2 support for Python, including all the handler
3226 interfaces needed to process XML 1.0 compliant XML. Some
3227 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003228
Fred Drake64bb3802000-09-26 16:21:35 +00003229- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
3230 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003231
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003232
Jeremy Hylton1b618592000-09-26 05:32:36 +00003233C API
3234
3235- Add three new convenience functions for module initialization --
3236 PyModule_AddObject(), PyModule_AddIntConstant(), and
3237 PyModule_AddStringConstant().
3238
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003239- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00003240 removed and add #error to Python.h if NULL isn't defined after
3241 #include of stdio.h.
3242
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003243- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00003244 backwards compatibility (at the source level) with old extensions.
3245
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003246- A wrapper API was added for signal() and sigaction(). Instead of
3247 either function, always use PyOS_getsig() to get a signal handler
3248 and PyOS_setsig() to set one. A new convenience typedef
3249 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003250
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003251- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00003252 internal data buffer and size of a string object -- or the default
3253 encoded version of a Unicode object.
3254
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003255- PyString_Size() and PyString_AsString() accept Unicode objects.
3256
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003257- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00003258 exists). INT_MAX and LONG_MAX will always be defined, even if
3259 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003260
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003261- PyFloat_FromString takes a second argument, pend, that was
3262 effectively useless. It is now officially useless but preserved for
3263 backwards compatibility. If the pend argument is not NULL, *pend is
3264 set to NULL.
3265
3266- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
3267 for the attribute name. See note on getattr() above.
3268
3269- A few bug fixes to argument processing for Unicode.
3270 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
3271 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
3272 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00003273 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003274
3275- Py_BuildValue accepts B format (for bgen-generated code).
3276
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003277
Jeremy Hylton1b618592000-09-26 05:32:36 +00003278Internals
3279
3280- On Unix, fix code for finding Python installation directory so that
3281 it works when argv[0] is a relative path.
3282
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00003283- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003284 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00003285 rather than by generating a copy of the object.
3286
Tim Peters482c0212000-09-26 06:33:09 +00003287- Several of the internal Unicode tables are much smaller now, and
3288 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003289
Jeremy Hylton97693b02000-09-26 17:42:51 +00003290- In the garbage collector: Fixed bug in collection of tuples. Fixed
3291 bug that caused some instances to be removed from the container set
3292 while they were still live. Fixed parsing in gc.set_debug() for
3293 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003294
3295- Fixed refcount problem in instance deallocation that only occurred
3296 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
3297
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003298- On Windows, getpythonregpath is now protected against null data in
3299 registry key.
3300
3301- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00003302 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003303
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003304
Jeremy Hylton1b618592000-09-26 05:32:36 +00003305Build and platform-specific issues
3306
3307- Better support of GNU Pth via --with-pth configure option.
3308
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003309- Python/C API now properly exposed to dynamically-loaded extension
3310 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003311
3312- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
3313 Don't define MS_SYNC to be zero when it is undefined. Added missing
3314 prototypes in posixmodule.c.
3315
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003316- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003317 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003318
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003319- Fix largefile support on older NetBSD systems and OpenBSD by adding
3320 define for TELL64.
3321
3322
3323Tools and other miscellany
3324
3325- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
3326
3327- freeze: The modulefinder now works with 2.0 opcodes.
3328
Tim Petersa3a3a032000-11-30 05:22:44 +00003329- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003330 Move hackery of sys.argv until after the Tk instance has been
3331 created, which allows the application-specific Tkinter
3332 initialization to be executed if present; also pass an explicit
3333 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00003334
Jeremy Hylton1b618592000-09-26 05:32:36 +00003335
3336What's new in 2.0 beta 1?
3337=========================
3338
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003339Source Incompatibilities
3340------------------------
3341
3342None. Note that 1.6 introduced several incompatibilities with 1.5.2,
3343such as single-argument append(), connect() and bind(), and changes to
3344str(long) and repr(float).
3345
3346
3347Binary Incompatibilities
3348------------------------
3349
3350- Third party extensions built for Python 1.5.x or 1.6 cannot be used
3351with Python 2.0; these extensions will have to be rebuilt for Python
33522.0.
3353
3354- On Windows, attempting to import a third party extension built for
3355Python 1.5.x or 1.6 results in an immediate crash; there's not much we
3356can do about this. Check your PYTHONPATH environment variable!
3357
3358- Python bytecode files (*.pyc and *.pyo) are not compatible between
3359releases.
3360
3361
3362Overview of Changes Since 1.6
3363-----------------------------
3364
3365There are many new modules (including brand new XML support through
3366the xml package, and i18n support through the gettext module); a list
3367of all new modules is included below. Lots of bugs have been fixed.
3368
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003369The process for making major new changes to the language has changed
3370since Python 1.6. Enhancements must now be documented by a Python
3371Enhancement Proposal (PEP) before they can be accepted.
3372
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003373There are several important syntax enhancements, described in more
3374detail below:
3375
3376 - Augmented assignment, e.g. x += 1
3377
3378 - List comprehensions, e.g. [x**2 for x in range(10)]
3379
3380 - Extended import statement, e.g. import Module as Name
3381
3382 - Extended print statement, e.g. print >> file, "Hello"
3383
3384Other important changes:
3385
3386 - Optional collection of cyclical garbage
3387
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003388Python Enhancement Proposal (PEP)
3389---------------------------------
3390
3391PEP stands for Python Enhancement Proposal. A PEP is a design
3392document providing information to the Python community, or describing
3393a new feature for Python. The PEP should provide a concise technical
3394specification of the feature and a rationale for the feature.
3395
3396We intend PEPs to be the primary mechanisms for proposing new
3397features, for collecting community input on an issue, and for
3398documenting the design decisions that have gone into Python. The PEP
3399author is responsible for building consensus within the community and
3400documenting dissenting opinions.
3401
3402The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003403
3404Augmented Assignment
3405--------------------
3406
3407This must have been the most-requested feature of the past years!
3408Eleven new assignment operators were added:
3409
Guido van Rossume905e952000-09-05 12:42:46 +00003410 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003411
3412For example,
3413
3414 A += B
3415
3416is similar to
3417
3418 A = A + B
3419
3420except that A is evaluated only once (relevant when A is something
3421like dict[index].attr).
3422
3423However, if A is a mutable object, A may be modified in place. Thus,
3424if A is a number or a string, A += B has the same effect as A = A+B
3425(except A is only evaluated once); but if a is a list, A += B has the
3426same effect as A.extend(B)!
3427
3428Classes and built-in object types can override the new operators in
3429order to implement the in-place behavior; the not-in-place behavior is
3430used automatically as a fallback when an object doesn't implement the
3431in-place behavior. For classes, the method name is derived from the
3432method name for the corresponding not-in-place operator by inserting
3433an 'i' in front of the name, e.g. __iadd__ implements in-place
3434__add__.
3435
3436Augmented assignment was implemented by Thomas Wouters.
3437
3438
3439List Comprehensions
3440-------------------
3441
3442This is a flexible new notation for lists whose elements are computed
3443from another list (or lists). The simplest form is:
3444
3445 [<expression> for <variable> in <sequence>]
3446
Guido van Rossum56db0952000-09-06 23:34:25 +00003447For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003448This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003449
3450You can also add a condition:
3451
3452 [<expression> for <variable> in <sequence> if <condition>]
3453
3454For example, [w for w in words if w == w.lower()] would yield the list
3455of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003456than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003457
3458You can also have nested for loops and more than one 'if' clause. For
3459example, here's a function that flattens a sequence of sequences::
3460
3461 def flatten(seq):
3462 return [x for subseq in seq for x in subseq]
3463
3464 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3465
3466This prints
3467
3468 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3469
3470List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003471Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003472
3473
3474Extended Import Statement
3475-------------------------
3476
3477Many people have asked for a way to import a module under a different
3478name. This can be accomplished like this:
3479
3480 import foo
3481 bar = foo
3482 del foo
3483
3484but this common idiom gets old quickly. A simple extension of the
3485import statement now allows this to be written as follows:
3486
3487 import foo as bar
3488
3489There's also a variant for 'from ... import':
3490
3491 from foo import bar as spam
3492
3493This also works with packages; e.g. you can write this:
3494
3495 import test.regrtest as regrtest
3496
3497Note that 'as' is not a new keyword -- it is recognized only in this
3498context (this is only possible because the syntax for the import
3499statement doesn't involve expressions).
3500
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003501Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003502
3503
3504Extended Print Statement
3505------------------------
3506
3507Easily the most controversial new feature, this extension to the print
3508statement adds an option to make the output go to a different file
3509than the default sys.stdout.
3510
3511For example, to write an error message to sys.stderr, you can now
3512write:
3513
3514 print >> sys.stderr, "Error: bad dog!"
3515
3516As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003517evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003518
3519 print >> None, "Hello world"
3520
3521is equivalent to
3522
3523 print "Hello world"
3524
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003525Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003526
3527
3528Optional Collection of Cyclical Garbage
3529---------------------------------------
3530
3531Python is now equipped with a garbage collector that can hunt down
3532cyclical references between Python objects. It's no replacement for
3533reference counting; in fact, it depends on the reference counts being
3534correct, and decides that a set of objects belong to a cycle if all
3535their reference counts can be accounted for from their references to
3536each other. This devious scheme was first proposed by Eric Tiedemann,
3537and brought to implementation by Neil Schemenauer.
3538
3539There's a module "gc" that lets you control some parameters of the
3540garbage collection. There's also an option to the configure script
3541that lets you enable or disable the garbage collection. In 2.0b1,
3542it's on by default, so that we (hopefully) can collect decent user
3543experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003544performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003545off by default in the final 2.0 release.
3546
3547
3548Smaller Changes
3549---------------
3550
3551A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3552map(None, seq1, seq2, ...) when the sequences have the same length;
3553i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3554the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003555zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003556
3557sys.version_info is a tuple (major, minor, micro, level, serial).
3558
3559Dictionaries have an odd new method, setdefault(key, default).
3560dict.setdefault(key, default) returns dict[key] if it exists; if not,
3561it sets dict[key] to default and returns that value. Thus:
3562
3563 dict.setdefault(key, []).append(item)
3564
3565does the same work as this common idiom:
3566
3567 if not dict.has_key(key):
3568 dict[key] = []
3569 dict[key].append(item)
3570
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003571There are two new variants of SyntaxError that are raised for
3572indentation-related errors: IndentationError and TabError.
3573
3574Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3575escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003576
3577The limits on the size of expressions and file in Python source code
3578have been raised from 2**16 to 2**32. Previous versions of Python
3579were limited because the maximum argument size the Python VM accepted
3580was 2**16. This limited the size of object constructor expressions,
3581e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3582limit was raised thanks to a patch by Charles Waldman that effectively
3583fixes the problem. It is now much more likely that you will be
3584limited by available memory than by an arbitrary limit in Python.
3585
3586The interpreter's maximum recursion depth can be modified by Python
3587programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3588limit is the maximum number of recursive calls that can be made by
3589Python code. The limit exists to prevent infinite recursion from
3590overflowing the C stack and causing a core dump. The default value is
35911000. The maximum safe value for a particular platform can be found
3592by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003593
3594New Modules and Packages
3595------------------------
3596
3597atexit - for registering functions to be called when Python exits.
3598
3599imputil - Greg Stein's alternative API for writing custom import
3600hooks.
3601
3602pyexpat - an interface to the Expat XML parser, contributed by Paul
3603Prescod.
3604
3605xml - a new package with XML support code organized (so far) in three
3606subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3607would fill a volume. There's a special feature whereby a
3608user-installed package named _xmlplus overrides the standard
3609xmlpackage; this is intended to give the XML SIG a hook to distribute
3610backwards-compatible updates to the standard xml package.
3611
3612webbrowser - a platform-independent API to launch a web browser.
3613
3614
Guido van Rossume905e952000-09-05 12:42:46 +00003615Changed Modules
3616---------------
3617
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003618array -- new methods for array objects: count, extend, index, pop, and
3619remove
3620
3621binascii -- new functions b2a_hex and a2b_hex that convert between
3622binary data and its hex representation
3623
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003624calendar -- Many new functions that support features including control
3625over which day of the week is the first day, returning strings instead
3626of printing them. Also new symbolic constants for days of week,
3627e.g. MONDAY, ..., SUNDAY.
3628
3629cgi -- FieldStorage objects have a getvalue method that works like a
3630dictionary's get method and returns the value attribute of the object.
3631
3632ConfigParser -- The parser object has new methods has_option,
3633remove_section, remove_option, set, and write. They allow the module
3634to be used for writing config files as well as reading them.
3635
3636ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003637optionally support the RFC 959 REST command.
3638
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003639gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003640
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003641httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3642the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003643
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003644locale -- implement getdefaultlocale for Win32 and Macintosh
3645
3646marshal -- no longer dumps core when marshaling deeply nested or
3647recursive data structures
3648
3649os -- new functions isatty, seteuid, setegid, setreuid, setregid
3650
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003651os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3652support under Unix.
3653
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003654os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003655
3656os.path -- fix semantics of os.path.commonprefix
3657
3658smtplib -- support for sending very long messages
3659
3660socket -- new function getfqdn()
3661
3662readline -- new functions to read, write and truncate history files.
3663The readline section of the library reference manual contains an
3664example.
3665
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003666select -- add interface to poll system call
3667
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003668shutil -- new copyfileobj function
3669
3670SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3671HTTP server.
3672
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003673Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003674
3675urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003676e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003677
3678whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003679
3680
3681Obsolete Modules
3682----------------
3683
3684None. However note that 1.6 made a whole slew of modules obsolete:
3685stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3686poly, zmod, strop, util, whatsound.
3687
3688
3689Changed, New, Obsolete Tools
3690----------------------------
3691
Tim Peters8b092332000-09-05 20:15:25 +00003692None.
Guido van Rossume905e952000-09-05 12:42:46 +00003693
3694
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003695C-level Changes
3696---------------
3697
3698Several cleanup jobs were carried out throughout the source code.
3699
3700All C code was converted to ANSI C; we got rid of all uses of the
3701Py_PROTO() macro, which makes the header files a lot more readable.
3702
3703Most of the portability hacks were moved to a new header file,
3704pyport.h; several other new header files were added and some old
3705header files were removed, in an attempt to create a more rational set
3706of header files. (Few of these ever need to be included explicitly;
3707they are all included by Python.h.)
3708
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003709Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003710and Win64, especially for the new Intel Itanium processor. Mick also
3711added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003712
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003713The C APIs to return an object's size have been update to consistently
3714use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3715previous versions, the abstract interfaces used PyXXX_Length and the
3716concrete interfaces used PyXXX_Size. The old names,
3717e.g. PyObject_Length, are still available for backwards compatibility
3718at the API level, but are deprecated.
3719
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003720The PyOS_CheckStack function has been implemented on Windows by
3721Fredrik Lundh. It prevents Python from failing with a stack overflow
3722on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003723
3724The GC changes resulted in creation of two new slots on object,
3725tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003726the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003727
3728The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003729C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003730
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003731PyErr_Format has been updated to automatically calculate the size of
3732the buffer needed to hold the formatted result string. This change
3733prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003734
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003735New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003736
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003737PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3738that are the same as their non-Ex counterparts except they take an
3739extra flag argument that tells them to close the file when done.
3740
3741XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003742
Tim Peters8b092332000-09-05 20:15:25 +00003743
3744Windows Changes
3745---------------
3746
3747New popen2/popen3/peopen4 in os module (see Changed Modules above).
3748
3749os.popen is much more usable on Windows 95 and 98. See Microsoft
3750Knowledge Base article Q150956. The Win9x workaround described there
3751is implemented by the new w9xpopen.exe helper in the root of your
3752Python installation. Note that Python uses this internally; it is not
3753a standalone program.
3754
3755Administrator privileges are no longer required to install Python
3756on Windows NT or Windows 2000. If you have administrator privileges,
3757Python's registry info will be written under HKEY_LOCAL_MACHINE.
3758Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003759under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003760uses of Python, but will prevent some advanced uses from working
3761(for example, running a Python script as an NT service, or possibly
3762from CGI).
3763
3764[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3765installer; instead, it installs the needed Tcl/Tk files directly in the
3766Python directory. If you already have a Tcl/Tk installation, this
3767wastes some disk space (about 4 Megs) but avoids problems with
3768conflicting Tcl/Tk installations, and makes it much easier for Python
3769to ensure that Tcl/Tk can find all its files.
3770
3771[This was new in 1.6] The Windows installer now installs by default in
3772\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3773
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003774
3775Updates to the changes between 1.5.2 and 1.6
3776--------------------------------------------
3777
3778The 1.6 NEWS file can't be changed after the release is done, so here
3779is some late-breaking news:
3780
3781New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3782and changes to getlocale() and setlocale().
3783
3784The new module is now enabled per default.
3785
3786It is not true that the encodings codecs cannot be used for normal
3787strings: the string.encode() (which is also present on 8-bit strings
3788!) allows using them for 8-bit strings too, e.g. to convert files from
3789cp1252 (Windows) to latin-1 or vice-versa.
3790
3791Japanese codecs are available from Tamito KAJIYAMA:
3792http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3793
3794
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003795======================================================================