blob: 5595d0180ed9818ffc1d910c03d11d55ab03051f [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
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00009 extension module). This prevents anomalies like 2.__class__ = bool.
Guido van Rossume3438782002-08-12 03:42:03 +000010
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,
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +0000162 and Ctrl+C at an interactive 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
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +0000301- Added operator.pow(a,b) which is equivalent to a**b.
302
Tim Peters012c0a32002-08-16 03:40:07 +0000303- random.randrange(-sys.maxint-1, sys.maxint) no longer raises
304 OverflowError. That is, it now accepts any combination of 'start'
305 and 'stop' arguments so long as each is in the range of Python's
306 bounded integers.
307
Guido van Rossum4a57c332002-08-02 18:05:20 +0000308- New "algorithms" module: heapq, implements a heap queue. Thanks to
309 Kevin O'Connor for the code and François Pinard for an entertaining
310 write-up explaining the theory and practical uses of heaps.
311
Marc-André Lemburg58e2ff22002-07-12 14:40:04 +0000312- New encoding for the Palm OS character set: palmos.
313
Tim Peters943382c2002-07-07 03:59:34 +0000314- binascii.crc32() and the zipfile module had problems on some 64-bit
315 platforms. These have been fixed. On a platform with 8-byte C longs,
316 crc32() now returns a signed-extended 4-byte result, so that its value
317 as a Python int is equal to the value computed a 32-bit platform.
318
Martin v. Löwis7d650ca2002-06-30 15:05:00 +0000319- xml.dom.minidom.toxml and toprettyxml now take an optional encoding
320 argument.
321
Guido van Rossum9f7549b2002-06-10 21:39:42 +0000322- Some fixes in the copy module: when an object is copied through its
323 __reduce__ method, there was no check for a __setstate__ method on
324 the result [SF patch 565085]; deepcopy should treat instances of
325 custom metaclasses the same way it treats instances of type 'type'
326 [SF patch 560794].
327
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000328- Sockets now support timeout mode. After s.settimeout(T), where T is
329 a float expressing seconds, subsequent operations raise an exception
330 if they cannot be completed within T seconds. To disable timeout
Guido van Rossum79f0a102002-07-23 03:32:08 +0000331 mode, use s.settimeout(None). There's also a module function,
332 socket.setdefaulttimeout(T), which sets the default for all sockets
333 created henceforth.
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000334
335- getopt.gnu_getopt was added. This supports GNU-style option
336 processing, where options can be mixed with non-option arguments.
Martin v. Löwis446a25f2002-06-06 10:58:36 +0000337
Michael W. Hudsonb0dc1a32002-06-04 18:27:35 +0000338- Stop using strings for exceptions. String objects used for
339 exceptions are now classes deriving from Exception. The objects
340 changed were: Tkinter.TclError, bdb.BdbQuit, macpath.norm_error,
341 tabnanny.NannyNag, and xdrlib.Error.
Neal Norwitzb5b5a262002-06-04 17:14:07 +0000342
Walter Dörwald474458d2002-06-04 15:16:29 +0000343- Constants BOM_UTF8, BOM_UTF16, BOM_UTF16_LE, BOM_UTF16_BE,
344 BOM_UTF32, BOM_UTF32_LE and BOM_UTF32_BE that represent the Byte
345 Order Mark in UTF-8, UTF-16 and UTF-32 encodings for little and
346 big endian systems were added to the codecs module. The old names
347 BOM32_* and BOM64_* were off by a factor of 2.
348
Guido van Rossumf9257822002-06-18 20:43:18 +0000349- Added conversion functions math.degrees() and math.radians().
Raymond Hettinger87f59ee2002-05-13 04:17:32 +0000350
Raymond Hettinger9b1df1d2002-05-12 06:07:21 +0000351- ftplib.retrlines() now tests for callback is None rather than testing
352 for False. Was causing an error when given a callback object which
353 was callable but also returned len() as zero. The change may
354 create new breakage if the caller relied on the undocumented behavior
355 and called with callback set to [] or some other False value not
356 identical to None.
357
Tim Peters46c04e12002-05-05 20:40:00 +0000358- random.gauss() uses a piece of hidden state used by nothing else,
359 and the .seed() and .whseed() methods failed to reset it. In other
360 words, setting the seed didn't completely determine the sequence of
361 results produced by random.gauss(). It does now. Programs repeatedly
362 mixing calls to a seed method with calls to gauss() may see different
363 results now.
364
Fred Drake7f781c92002-05-01 20:33:53 +0000365- The pickle.Pickler class grew a clear_memo() method to mimic that
366 provided by cPickle.Pickler.
367
Tim Peters81b92512002-04-29 01:37:32 +0000368- difflib's SequenceMatcher class now does a dynamic analysis of
369 which elements are so frequent as to constitute noise. For
370 comparing files as sequences of lines, this generally works better
371 than the IS_LINE_JUNK function, and function ndiff's linejunk
372 argument defaults to None now as a result. A happy benefit is
373 that SequenceMatcher may run much faster now when applied
374 to large files with many duplicate lines (for example, C program
375 text with lots of repeated "}" and "return NULL;" lines).
376
Guido van Rossum256705b2002-04-23 13:29:43 +0000377- New Text.dump() method in Tkinter module.
378
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000379- New distutils commands for building packagers were added to
380 support pkgtool on Solaris and swinstall on HP-UX.
381
382- distutils now has a new abstract binary packager base class
383 command/bdist_packager, which simplifies writing packagers.
384 This will hopefully provide the missing bits to encourage
385 people to submit more packagers, e.g. for Debian, FreeBSD
386 and other systems.
387
Guido van Rossumf9257822002-06-18 20:43:18 +0000388- The UTF-16, -LE and -BE stream readers now raise a
389 NotImplementedError for all calls to .readline(). Previously, they
390 used to just produce garbage or fail with an encoding error --
391 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 +0000392 work well with these.
393
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000394- compileall now supports quiet operation.
395
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000396- The BaseHTTPServer now implements optional HTTP/1.1 persistent
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000397 connections.
398
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000399- socket module: the SSL support was broken out of the main
400 _socket module C helper and placed into a new _ssl helper
401 which now gets imported by socket.py if available and working.
402
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000403- encodings package: added aliases for all supported IANA character
404 sets
405
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000406- ftplib: to safeguard the user's privacy, anonymous login will use
407 "anonymous@" as default password, rather than the real user and host
408 name.
409
Fred Drake36736122002-01-10 13:50:31 +0000410- webbrowser: tightened up the command passed to os.system() so that
411 arbitrary shell code can't be executed because a bogus URL was
412 passed in.
413
Tim Peters11bd9942002-02-01 00:52:29 +0000414- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000415 gettext.find an optional all argument. Translations will now fallback
416 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000417
Martin v. Löwis9668b932002-01-12 11:27:42 +0000418- distutils bdist commands now offer a --skip-build option.
419
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000420- warnings.warn now accepts a Warning instance as first argument.
421
Fred Drakefed7e852002-04-04 19:36:15 +0000422- The xml.sax.expatreader.ExpatParser class will no longer create
423 circular references by using itself as the locator that gets passed
424 to the content handler implementation. [SF bug #535474]
425
Barry Warsaw47f3e2c2002-05-20 00:14:24 +0000426- The email.Parser.Parser class now properly parses strings regardless
427 of their line endings, which can be any of \r, \n, or \r\n (CR, LF,
428 or CRLF). Also, the Header class's constructor default arguments
429 has changed slightly so that an explicit maxlinelen value is always
430 honored.
431
Tim Petersaf8446f2001-12-21 21:36:50 +0000432Tools/Demos
433
Fred Drake40813b12002-08-05 15:24:19 +0000434- IDLE supports the new encoding declarations (PEP 263); it can also
435 deal with legacy 8-bit files if they use the locale's encoding. It
436 allows non-ASCII strings in the interactive shell and executes them
437 in the locale's encoding.
Martin v. Löwis98ce7b72002-08-05 15:11:26 +0000438
Marc-André Lemburg46260092002-04-04 16:17:11 +0000439- freeze.py now produces binaries which can import shared modules,
440 unlike before when this failed due to missing symbol exports in
441 the generated binary.
442
Tim Petersaf8446f2001-12-21 21:36:50 +0000443Build
444
Tim Petersf47630f2002-08-01 02:34:51 +0000445- The public Python C API will generally be declared using PyAPI_FUNC
Neal Norwitz1389f3e2002-07-22 13:21:10 +0000446 and PyAPI_DATA macros, while Python extension module init functions
447 will be declared with PyMODINIT_FUNC. DL_EXPORT/DL_IMPORT macros
448 are deprecated.
449
Tim Petersc6a3ff62002-07-08 22:11:52 +0000450- A bug was fixed that could cause COUNT_ALLOCS builds to segfault, or
451 get into infinite loops, when a new-style class got garbage-collected.
452 Unfortunately, to avoid this, the way COUNT_ALLOCS works requires
453 that new-style classes be immortal in COUNT_ALLOCS builds. Note that
454 COUNT_ALLOCS is not enabled by default, in either release or debug
455 builds, and that new-style classes are immortal only in COUNT_ALLOCS
456 builds.
457
Tim Peters943382c2002-07-07 03:59:34 +0000458- Compiling out the cyclic garbage collector is no longer an option.
459 The old symbol WITH_CYCLE_GC is now ignored, and Python.h arranges
460 that it's always defined (for the benefit of any extension modules
461 that may be conditionalizing on it). A bonus is that any extension
462 type participating in cyclic gc can choose to participate in the
463 Py_TRASHCAN mechanism now too; in the absence of cyclic gc, this used
464 to require editing the core to teach the trashcan mechanism about the
465 new type.
466
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000467- According to Annex F of the current C standard,
Tim Peters1de41bf2002-07-03 03:31:20 +0000468
469 The Standard C macro HUGE_VAL and its float and long double analogs,
470 HUGE_VALF and HUGE_VALL, expand to expressions whose values are
471 positive infinities.
472
473 Python only uses the double HUGE_VAL, and only to #define its own symbol
474 Py_HUGE_VAL. Some platforms have incorrect definitions for HUGE_VAL.
475 pyport.h used to try to worm around that, but the workarounds triggered
476 other bugs on other platforms, so we gave up. If your platform defines
477 HUGE_VAL incorrectly, you'll need to #define Py_HUGE_VAL to something
478 that works on your platform. The only instance of this I'm sure about
479 is on an unknown subset of Cray systems, described here:
480
481 http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm
482
483 Presumably 2.3a1 breaks such systems. If anyone uses such a system, help!
484
Martin v. Löwisa3fb4f72002-06-09 13:33:54 +0000485- The configure option --without-doc-strings can be used to remove the
486 doc strings from the builtin functions and modules; this reduces the
487 size of the executable.
488
Guido van Rossumadd88062002-08-15 14:01:14 +0000489- The universal newlines option (PEP 278) is on by default. On Unix
490 it can be disabled by passing --without-universal-newlines to the
491 configure script. On other platforms, remove
492 WITH_UNIVERSAL_NEWLINES from pyconfig.h.
Tim Peters639295f2002-04-21 07:30:30 +0000493
Martin v. Löwis1142de32002-03-29 16:28:31 +0000494- On Unix, a shared libpython2.3.so can be created with --enable-shared.
495
Tim Peters8deda702002-03-30 10:06:07 +0000496- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
497 preprocessor symbols were eliminated. The internal decisions they
498 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000499
Fred Drake7d28b732002-05-02 21:17:00 +0000500- The tools used to build the documentation now work under Cygwin as
501 well as Unix.
502
Skip Montanaro57454e52002-06-14 20:30:31 +0000503- The bsddb and dbm module builds have been changed to try and avoid version
504 skew problems and disable linkage with Berkeley DB 1.85 unless the
505 installer knows what s/he's doing. See the section on building these
506 modules in the README file for details.
507
Tim Petersaf8446f2001-12-21 21:36:50 +0000508C API
509
Guido van Rossumfdb86482002-08-14 21:20:32 +0000510- The Py_InitModule*() functions now accept NULL for the 'methods'
511 argument. Modules without global functions are becoming more common
512 now that factories can be types rather than functions.
513
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +0000514- New C API PyUnicode_FromOrdinal() which exposes unichr() at C
515 level.
516
Thomas Heller085358a2002-07-29 14:27:41 +0000517- New functions PyErr_SetExcFromWindowsErr() and
518 PyErr_SetExcFromWindowsErrWithFilename(). Similar to
519 PyErr_SetFromWindowsErrWithFilename() and
520 PyErr_SetFromWindowsErr(), but they allow to specify
521 the exception type to raise. Available on Windows.
522
Tim Peters7c321a82002-07-09 02:57:01 +0000523- Py_FatalError() is now declared as taking a const char* argument. It
524 was previously declared without const. This should not affect working
525 code.
526
Martin v. Löwis01f94bd2002-05-08 08:44:21 +0000527- Added new macro PySequence_ITEM(o, i) that directly calls
528 sq_item without rechecking that o is a sequence and without
529 adjusting for negative indices.
530
Fred Draked0ba6362002-05-02 21:28:26 +0000531- PyRange_New() now raises ValueError if the fourth argument is not 1.
532 This is part of the removal of deprecated features of the xrange
533 object.
534
Guido van Rossum517c7d42002-04-26 02:49:14 +0000535- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
536 coercion if both arguments have the same type but this type has the
537 CHECKTYPES flag set. This is to better support proxies.
538
Neil Schemenauer9344b142002-04-12 23:00:08 +0000539- The type of tp_free has been changed from "void (*)(PyObject *)" to
540 "void (*)(void *)".
541
542- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
543
Guido van Rossum0986d822002-04-08 01:38:42 +0000544- A type can now inherit its metatype from its base type. Previously,
545 when PyType_Ready() was called, if ob_type was found to be NULL, it
546 was always set to &PyType_Type; now it is set to base->ob_type,
547 where base is tp_base, defaulting to &PyObject_Type.
548
549- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
550
Neil Schemenauerc9abc1d2002-05-08 14:14:41 +0000551- The PyCore_* family of APIs have been removed.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000552
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000553- The "u#" parser marker will now pass through Unicode objects as-is
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000554 without going through the buffer API.
555
Martin v. Löwis7198a522002-01-01 19:59:11 +0000556- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
557
Tim Peters10a3bb52001-12-25 19:07:38 +0000558- An old #define of ANY as void has been removed from pyport.h. This
559 hasn't been used since Python's pre-ANSI days, and the #define has
560 been marked as obsolete since then. SF bug 495548 says it created
561 conflicts with other packages, so keeping it around wasn't harmless.
562
Tim Petersaf8446f2001-12-21 21:36:50 +0000563- Because Python's magic number scheme broke on January 1st, we decided
564 to stop Python development. Thanks for all the fish!
565
Tim Petersfb05db22002-03-11 00:24:00 +0000566- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000567 scheme to a new one. See Python/import.c for details.
568
Tim Petersaf8446f2001-12-21 21:36:50 +0000569New platforms
570
Martin v. Löwisf90ae202002-06-11 06:22:31 +0000571- AtheOS is now supported.
572
Andrew MacIntyre161ad0e2002-08-04 07:25:58 +0000573- the EMX runtime environment on OS/2 is now supported.
574
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000575- GNU/Hurd is now supported.
576
Tim Petersaf8446f2001-12-21 21:36:50 +0000577Tests
578
579Windows
580
Tim Peters08e72952002-04-16 20:48:01 +0000581- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
582 of that has been fixed in the installer (disabled Wise's "delete in-
583 use files" uninstall option).
584
Guido van Rossum181e41a2002-04-06 00:23:25 +0000585- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
586
Tim Peters33187922002-04-04 20:02:04 +0000587- The installer now installs Start menu shortcuts under (the local
588 equivalent of) "All Users" when doing an Admin install.
589
Tim Petersfb05db22002-03-11 00:24:00 +0000590- file.truncate([newsize]) now works on Windows for all newsize values.
591 It used to fail if newsize didn't fit in 32 bits, reflecting a
592 limitation of MS _chsize (which is no longer used).
593
Tim Petersab034fa2002-02-01 11:27:43 +0000594- os.waitpid() is now implemented for Windows, and can be used to block
595 until a specified process exits. This is similar to, but not exactly
596 the same as, os.waitpid() on POSIX systems. If you're waiting for
597 a specific process whose pid was obtained from one of the spawn()
598 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000599 See the docs for details. The docs were changed to clarify that
600 spawn functions return, and waitpid requires, a process handle on
601 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000602
Tim Peters11bd9942002-02-01 00:52:29 +0000603- New tempfile.TemporaryFile implementation for Windows: this doesn't
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000604 need a TemporaryFileWrapper wrapper anymore, and should be immune
Tim Peters11bd9942002-02-01 00:52:29 +0000605 to a nasty problem: before 2.3, if you got a temp file on Windows, it
606 got wrapped in an object whose close() method first closed the
607 underlying file, then deleted the file. This usually worked fine.
608 However, the spawn family of functions on Windows create (at a low C
609 level) the same set of open files in the spawned process Q as were
610 open in the spawning process P. If a temp file f was among them, then
611 doing f.close() in P first closed P's C-level file handle on f, but Q's
612 C-level file handle on f remained open, so the attempt in P to delete f
613 blew up with a "Permission denied" error (Windows doesn't allow
614 deleting open files). This was surprising, subtle, and difficult to
615 work around.
616
617- The os module now exports all the symbolic constants usable with the
618 low-level os.open() on Windows: the new constants in 2.3 are
619 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
620 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
621 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
622 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
623 (so specify both if you want both; note that neither is useful unless
624 specified with O_CREAT too).
625
Tim Petersaf8446f2001-12-21 21:36:50 +0000626Mac
627
628
Tim Peters909c0912001-12-14 23:16:18 +0000629What's New in Python 2.2 final?
630Release date: 21-Dec-2001
631===============================
632
633Type/class unification and new-style classes
634
Barry Warsaw52acb492001-12-21 20:04:22 +0000635- pickle.py, cPickle: allow pickling instances of new-style classes
636 with a custom metaclass.
637
Tim Peters909c0912001-12-14 23:16:18 +0000638Core and builtins
639
Barry Warsaw52acb492001-12-21 20:04:22 +0000640- weakref proxy object: when comparing, unwrap both arguments if both
641 are proxies.
642
Tim Peters909c0912001-12-14 23:16:18 +0000643Extension modules
644
Barry Warsaw52acb492001-12-21 20:04:22 +0000645- binascii.b2a_base64(): fix a potential buffer overrun when encoding
646 very short strings.
647
648- cPickle: the obscure "fast" mode was suspected of causing stack
649 overflows on the Mac. Hopefully fixed this by setting the recursion
650 limit much smaller. If the limit is too low (it only affects
651 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
652 when compiling cPickle.c (or in pyconfig.h).
653
Tim Peters909c0912001-12-14 23:16:18 +0000654Library
655
Barry Warsaw52acb492001-12-21 20:04:22 +0000656- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
657 close or delete time).
658
659- rfc822.py: fixed a bug where the address '<>' was converted to None
660 instead of an empty string (also fixes the email.Utils module).
661
662- xmlrpclib.py: version 1.0.0; uses precision for doubles.
663
664- test suite: the pickle and cPickle tests were not executing any code
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000665 when run from the standard regression test.
Barry Warsaw52acb492001-12-21 20:04:22 +0000666
Tim Peters909c0912001-12-14 23:16:18 +0000667Tools/Demos
668
669Build
670
671C API
672
673New platforms
674
675Tests
676
677Windows
678
Barry Warsaw52acb492001-12-21 20:04:22 +0000679- distutils package: fixed broken Windows installers (bdist_wininst).
680
681- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
682 instances are deleted at process exit time.
683
684- socket.py: prevent mysterious warnings when socket instances are
685 deleted at process exit time.
686
687- posixmodule.c: fix a Windows crash with stat() of a filename ending
688 in backslash.
689
Tim Peters909c0912001-12-14 23:16:18 +0000690Mac
691
Barry Warsaw52acb492001-12-21 20:04:22 +0000692- The Carbon toolbox modules have been upgraded to Universal Headers
693 3.4, and experimental CoreGraphics and CarbonEvents modules have
694 been added. All only for framework-enabled MacOSX.
695
Tim Peters909c0912001-12-14 23:16:18 +0000696
Tim Peters6272dfd2001-12-13 19:34:00 +0000697What's New in Python 2.2c1?
698Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000699===========================
700
701Type/class unification and new-style classes
702
Barry Warsaw06557452001-12-14 20:47:12 +0000703- Guido's tutorial introduction to the new type/class features has
704 been extensively updated. See
705
706 http://www.python.org/2.2/descrintro.html
707
708 That remains the primary documentation in this area.
709
Guido van Rossum33bab012001-12-05 22:45:48 +0000710- Fixed a leak: instance variables declared with __slots__ were never
711 deleted!
712
Guido van Rossum4b800852001-12-03 00:54:52 +0000713- The "delete attribute" method of descriptor objects is called
714 __delete__, not __del__. In previous releases, it was mistakenly
715 called __del__, which created an unfortunate overloading condition
716 with finalizers. (The "get attribute" and "set attribute" methods
717 are still called __get__ and __set__, respectively.)
718
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000719- Some subtle issues with the super built-in were fixed:
720
721 (a) When super itself is subclassed, its __get__ method would still
722 return an instance of the base class (i.e., of super).
723
724 (b) super(C, C()).__class__ would return C rather than super. This
725 is confusing. To fix this, I decided to change the semantics of
726 super so that it only applies to code attributes, not to data
727 attributes. After all, overriding data attributes is not
728 supported anyway.
729
730 (c) The __get__ method didn't check whether the argument was an
731 instance of the type used in creation of the super instance.
732
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000733- Previously, hash() of an instance of a subclass of a mutable type
734 (list or dictionary) would return some value, rather than raising
735 TypeError. This has been fixed. Also, directly calling
736 dict.__hash__ and list.__hash__ now raises the same TypeError
737 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000738
Guido van Rossumd331cb52001-12-05 19:46:42 +0000739- New-style objects now support deleting their __dict__. This is for
740 all intents and purposes equivalent to assigning a brand new empty
741 dictionary, but saves space if the object is not used further.
742
Tim Petersb3c9af12001-11-17 00:21:57 +0000743Core and builtins
744
Tim Peters3caca232001-12-06 06:23:26 +0000745- -Qnew now works as documented in PEP 238: when -Qnew is passed on
746 the command line, all occurrences of "/" use true division instead
747 of classic division. See the PEP for details. Note that "all"
748 means all instances in library and 3rd-party modules, as well as in
749 your own code. As the PEP says, -Qnew is intended for use only in
750 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000751 Note that test_coercion.py in the standard Python test suite fails
752 under -Qnew; this is expected, and won't be repaired until true
753 division becomes the default (in the meantime, test_coercion is
754 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000755
Fred Drake6c01e252001-12-14 17:08:12 +0000756- complex() now only allows the first argument to be a string
757 argument, and raises TypeError if either the second arg is a string
758 or if the second arg is specified when the first is a string.
759
Tim Petersb3c9af12001-11-17 00:21:57 +0000760Extension modules
761
Martin v. Löwis560da622001-11-24 09:24:51 +0000762- gc.get_referents was renamed to gc.get_referrers.
763
Tim Petersb3c9af12001-11-17 00:21:57 +0000764Library
765
Tim Peters25059d32001-12-07 20:35:43 +0000766- Functions in the os.spawn() family now release the global interpreter
767 lock around calling the platform spawn. They should always have done
768 this, but did not before 2.2c1. Multithreaded programs calling
769 an os.spawn function with P_WAIT will no longer block all Python threads
770 until the spawned program completes. It's possible that some programs
771 relies on blocking, although more likely by accident than by design.
772
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000773- webbrowser defaults to netscape.exe on OS/2 now.
774
Martin v. Löwis652e1912001-11-25 14:50:56 +0000775- Tix.ResizeHandle exposes detach_widget, hide, and show.
776
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000777- The charset alias windows_1252 has been added.
778
Barry Warsaw06557452001-12-14 20:47:12 +0000779- types.StringTypes is a tuple containing the defined string types;
780 usually this will be (str, unicode), but if Python was compiled
781 without Unicode support it will be just (str,).
782
783- The pulldom and minidom modules were synchronized to PyXML.
784
Tim Petersb3c9af12001-11-17 00:21:57 +0000785Tools/Demos
786
Barry Warsaw06557452001-12-14 20:47:12 +0000787- A new script called Tools/scripts/google.py was added, which fires
788 off a search on Google.
789
Tim Petersb3c9af12001-11-17 00:21:57 +0000790Build
791
Barry Warsaw06557452001-12-14 20:47:12 +0000792- Note that release builds of Python should arrange to define the
793 preprocessor symbol NDEBUG on the command line (or equivalent).
794 In the 2.2 pre-release series we tried to define this by magic in
795 Python.h instead, but it proved to cause problems for extension
796 authors. The Unix, Windows and Mac builds now all define NDEBUG in
797 release builds via cmdline (or equivalent) instead. Ports to
798 other platforms should do likewise.
799
Jack Jansen1999ef42001-12-06 21:47:20 +0000800- It is no longer necessary to use --with-suffix when building on a
801 case-insensitive file system (such as Mac OS X HFS+). In the build
802 directory an extension is used, but not in the installed python.
803
Tim Petersb3c9af12001-11-17 00:21:57 +0000804C API
805
Tim Petersf582b822001-12-11 18:51:08 +0000806- New function PyDict_MergeFromSeq2() exposes the builtin dict
807 constructor's logic for updating a dictionary from an iterable object
808 producing key-value pairs.
809
Tim Peterscffed4b2001-11-29 03:26:37 +0000810- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000811 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000812 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
813 dump core in some bad cases. This has been repaired. As a result,
814 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
815 previously went unchallenged.
816
Tim Petersb3c9af12001-11-17 00:21:57 +0000817New platforms
818
819Tests
820
821Windows
822
823Mac
824
Jack Jansenffa260f2001-12-06 21:14:00 +0000825- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
826 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000827
Barry Warsaw06557452001-12-14 20:47:12 +0000828- Changed logic for finding python home in Mac OS X framework Pythons.
829 Now sys.executable points to the executable again, in stead of to
830 the shared library. The latter is used only for locating the python
831 home.
832
833
Tim Peters84362bc2001-10-19 17:55:30 +0000834What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000835Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000836===========================
837
838Type/class unification and new-style classes
839
Guido van Rossum3d27df02001-11-15 20:27:54 +0000840- Multiple inheritance mixing new-style and classic classes in the
841 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000842
843 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000844 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000845
846 The MRO (method resolution order) for each base class is respected
847 according to its kind, but the MRO for the derived class is computed
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000848 using new-style MRO rules if any base class is a new-style class.
Tim Peters76f7fe32001-11-15 20:02:21 +0000849 This needs to be documented.
850
Tim Petersa427a2b2001-10-29 22:25:45 +0000851- The new builtin dictionary() constructor, and dictionary type, have
852 been renamed to dict. This reflects a decade of common usage.
853
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000854- dict() now accepts an iterable object producing 2-sequences. For
855 example, dict(d.items()) == d for any dictionary d. The argument,
856 and the elements of the argument, can be any iterable objects.
857
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000858- New-style classes can now have a __del__ method, which is called
859 when the instance is deleted (just like for classic classes).
860
Guido van Rossum12d955c2001-10-26 14:56:06 +0000861- Assignment to object.__dict__ is now possible, for objects that are
862 instances of new-style classes that have a __dict__ (unless the base
863 class forbids it).
864
Guido van Rossumc8e56452001-10-22 00:43:43 +0000865- Methods of built-in types now properly check for keyword arguments
866 (formerly these were silently ignored). The only built-in methods
867 that take keyword arguments are __call__, __init__ and __new__.
868
Guido van Rossum86443212001-10-27 22:28:54 +0000869- The socket function has been converted to a type; see below.
870
Tim Peters84362bc2001-10-19 17:55:30 +0000871Core and builtins
872
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000873- Assignment to __debug__ raises SyntaxError at compile-time. This
874 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000875 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000876
Guido van Rossum12d955c2001-10-26 14:56:06 +0000877- Clarified the error messages for unsupported operands to an operator
878 (like 1 + '').
879
Tim Peters84362bc2001-10-19 17:55:30 +0000880Extension modules
881
Tim Peters5ebfd362001-11-13 23:11:19 +0000882- mmap has a new keyword argument, "access", allowing a uniform way for
883 both Windows and Unix users to create read-only, write-through and
884 copy-on-write memory mappings. This was previously possible only on
885 Unix. A new keyword argument was required to support this in a
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000886 uniform way because the mmap() signatures had diverged across
Tim Peters5ebfd362001-11-13 23:11:19 +0000887 platforms. Thanks to Jay T Miller for repairing this!
888
Tim Peters169ded02001-11-03 19:57:21 +0000889- By default, the gc.garbage list now contains only those instances in
890 unreachable cycles that have __del__ methods; in 2.1 it contained all
891 instances in unreachable cycles. "Instances" here has been generalized
892 to include instances of both new-style and old-style classes.
893
Guido van Rossum12d955c2001-10-26 14:56:06 +0000894- The socket module defines a new method for socket objects,
895 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000896 send() until all data has been sent. Also, the socket function has
897 been converted to a subclassable type, like list and tuple (etc.)
898 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000899
900- Various bugfixes to the curses module. There is now a test suite
901 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000902
Guido van Rossum692adf12001-10-30 03:03:03 +0000903- binascii.b2a_base64 no longer places an arbitrary restriction of 57
904 bytes on its input.
905
Tim Peters84362bc2001-10-19 17:55:30 +0000906Library
907
Tim Peters5ebfd362001-11-13 23:11:19 +0000908- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000909 convenience function.
910
Tim Peters75335872001-11-03 19:35:43 +0000911- Symbolic group names in regular expressions must be unique. For
912 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
913 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000914 Python 2.2 detects this error at regexp compilation time;
915 previously, the error went undetected, and results were
916 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
917 pattern.subn() methods have been rewritten in C. Also, an
918 experimental function/method finditer() has been added, which works
919 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000920
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000921- Tix exposes more commands through the classes DirSelectBox,
922 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
923 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
924 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
925
Tim Peters98791af2001-10-23 01:59:54 +0000926- Traceback objects are now scanned by cyclic garbage collection, so
927 cycles created by casual use of sys.exc_info() no longer cause
928 permanent memory leaks (provided garbage collection is enabled).
929
Guido van Rossum49192142001-10-24 20:51:44 +0000930- os.extsep -- a new variable needed by the RISCOS support. It is the
931 separator used by extensions, and is '.' on all platforms except
932 RISCOS, where it is '/'. There is no need to use this variable
933 unless you have a masochistic desire to port your code to RISCOS.
934
Barry Warsaw012852b2001-11-16 16:17:27 +0000935- mimetypes.py has optional support for non-standard, but commonly
936 found types. guess_type() and guess_extension() now accept an
937 optional `strict' flag, defaulting to true, which controls whether
938 recognize non-standard types or not. A few non-standard types we
939 know about have been added. Also, when run as a script, there are
940 new -l and -e options.
941
942- statcache is now deprecated.
943
944- email.Utils.formatdate() now produces the preferred RFC 2822 style
945 dates with numeric timezones (it used to produce obsolete dates
946 hard coded to "GMT" timezone). An optional `localtime' flag is
947 added to produce dates in the local timezone, with daylight savings
948 time properly taken into account.
949
950- In pickle and cPickle, instead of masking errors in load() by
951 transforming them into SystemError, we let the original exception
952 propagate out. Also, implement support for __safe_for_unpickling__
953 in pickle, as it already was supported in cPickle.
954
Tim Peters84362bc2001-10-19 17:55:30 +0000955Tools/Demos
956
957Build
958
Barry Warsaw012852b2001-11-16 16:17:27 +0000959- The dbm module is built using libdb1 if available. The bsddb module
960 is built with libdb3 if available.
961
962- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
963
Tim Peters84362bc2001-10-19 17:55:30 +0000964C API
965
Tim Peters1fc240e2001-10-26 05:06:50 +0000966- New function PySequence_Fast_GET_SIZE() returns the size of a non-
967 NULL result from PySequence_Fast(), more quickly than calling
968 PySequence_Size().
969
Barry Warsaw012852b2001-11-16 16:17:27 +0000970- New argument unpacking function PyArg_UnpackTuple() added.
971
972- New functions PyObject_CallFunctionObjArgs() and
973 PyObject_CallMethodObjArgs() have been added to make it more
974 convenient and efficient to call functions and methods from C.
975
976- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
977 possible that this will propagate errors it didn't before.
978
979- New function PyObject_CheckReadBuffer(), which returns true if its
980 argument supports the single-segment readable buffer interface.
981
Tim Peters84362bc2001-10-19 17:55:30 +0000982New platforms
983
Guido van Rossum86443212001-10-27 22:28:54 +0000984- We've finally confirmed that this release builds on HP-UX 11.00,
985 *with* threads, and passes the test suite.
986
Tim Peters7a33d8b2001-11-05 02:51:07 +0000987- Thanks to a series of patches from Michael Muller, Python may build
988 again under OS/2 Visual Age C++.
989
Guido van Rossum49192142001-10-24 20:51:44 +0000990- Updated RISCOS port by Dietmar Schwertberger.
991
Tim Peters84362bc2001-10-19 17:55:30 +0000992Tests
993
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000994- Added a test script for the curses module. It isn't run automatically;
995 regrtest.py must be run with '-u curses' to enable it.
996
Tim Peters84362bc2001-10-19 17:55:30 +0000997Windows
998
Barry Warsaw012852b2001-11-16 16:17:27 +0000999Mac
1000
1001- PythonScript has been moved to unsupported and is slated to be
1002 removed completely in the next release.
1003
1004- It should now be possible to build applets that work on both OS9 and
1005 OSX.
1006
1007- The core is now linked with CoreServices not Carbon; as a side
1008 result, default 8bit encoding on OSX is now ASCII.
1009
1010- Python should now build on OSX 10.1.1
1011
Tim Peters84362bc2001-10-19 17:55:30 +00001012
Tim Petersabf925f2001-09-28 21:53:42 +00001013What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +00001014Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +00001015===========================
1016
1017Type/class unification and new-style classes
1018
Guido van Rossum687ae002001-10-15 22:03:32 +00001019- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001020 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +00001021 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001022 remains: the __dict__ of a new-style class is a read-only proxy; you
1023 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +00001024 __defined__ attribute of new-style types no longer exists, for lack
1025 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001026 future a __cache__ may be resurrected with a similar function, if I
1027 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +00001028
Tim Peters1c9ca872001-10-04 06:43:12 +00001029- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
1030 always returned None, even when there was a class docstring).
1031
1032- doctest now finds and runs docstrings attached to new-style classes,
1033 class methods, static methods, and properties.
1034
Guido van Rossum9074ef62001-10-16 21:34:49 +00001035Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +00001036
Guido van Rossuma8bcf802001-10-15 15:53:58 +00001037- A very subtle syntactical pitfall in list comprehensions was fixed.
1038 For example: [a+b for a in 'abc', for b in 'def']. The comma in
1039 this example is a mistake. Previously, this would silently let 'a'
1040 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
1041 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
1042 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
1043 Note that [a for a in <singleton>] is a convoluted way to say
1044 [<singleton>] anyway, so it's not like any expressiveness is lost.
1045
Guido van Rossum9074ef62001-10-16 21:34:49 +00001046- getattr(obj, name, default) now only catches AttributeError, as
1047 documented, rather than returning the default value for all
1048 exceptions (which could mask bugs in a __getattr__ hook, for
1049 example).
1050
Fred Drakecb7a6b52001-10-22 18:41:51 +00001051- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +00001052 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001053 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +00001054 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +00001055
Guido van Rossum1c486092001-10-19 02:05:35 +00001056- unicode(obj) now behaves more like str(obj), accepting arbitrary
1057 objects, and calling a __unicode__ method if it exists.
1058 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +00001059 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +00001060
Barry Warsawf6fb1712001-10-19 05:35:40 +00001061- isinstance() now allows any object as the first argument and a
1062 class, a type or something with a __bases__ tuple attribute for the
1063 second argument. The second argument may also be a tuple of a
1064 class, type, or something with __bases__, in which case isinstance()
1065 will return true if the first argument is an instance of any of the
1066 things contained in the second argument tuple. E.g.
1067
1068 isinstance(x, (A, B))
1069
1070 returns true if x is an instance of A or B.
1071
Guido van Rossum9074ef62001-10-16 21:34:49 +00001072Extension modules
1073
1074- thread.start_new_thread() now returns the thread ID (previously None).
1075
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001076- binascii has now two quopri support functions, a2b_qp and b2a_qp.
1077
Guido van Rossumc524d952001-10-19 01:31:59 +00001078- readline now supports setting the startup_hook and the
1079 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +00001080
Guido van Rossumc524d952001-10-19 01:31:59 +00001081- os and posix supports chroot(), setgroups() and unsetenv() where
1082 available. The stat(), fstat(), statvfs() and fstatvfs() functions
1083 now return "pseudo-sequences" -- the various fields can now be
1084 accessed as attributes (e.g. os.stat("/").st_mtime) but for
1085 backwards compatibility they also behave as a fixed-length sequence.
1086 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +00001087 attributes.
1088
1089- time: localtime(), gmtime() and strptime() now return a
1090 pseudo-sequence similar to the os.stat() return value, with
1091 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +00001092
Guido van Rossum9074ef62001-10-16 21:34:49 +00001093- Decompression objects in the zlib module now accept an optional
1094 second parameter to decompress() that specifies the maximum amount
1095 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +00001096
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001097- optional SSL support in the socket module now exports OpenSSL
1098 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
1099 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +00001100 automatically seed its PRNG. Also, the keyfile and certfile
1101 arguments to socket.ssl() are now optional.
1102
1103- posixmodule (and by extension, the os module on POSIX platforms) now
1104 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001105
Guido van Rossum9074ef62001-10-16 21:34:49 +00001106Library
Guido van Rossum3c288632001-10-16 21:13:49 +00001107
Tim Peters7402f792001-10-02 03:53:41 +00001108- doctest now excludes functions and classes not defined by the module
1109 being tested, thanks to Tim Hochberg.
1110
Fred Drakecb7a6b52001-10-22 18:41:51 +00001111- HotShot, a new profiler implemented using a C-based callback, has
1112 been added. This substantially reduces the overhead of profiling,
1113 but it is still quite preliminary. Support modules and
1114 documentation will be added in upcoming releases (before 2.2 final).
1115
Guido van Rossumc4b09b42001-10-04 10:19:00 +00001116- profile now produces correct output in situations where an exception
1117 raised in Python is cleared by C code (e.g. hasattr()). This used
1118 to cause wrong output, including spurious claims of recursive
1119 functions and attribution of time spent to the wrong function.
1120
Tim Peters0a1fc4e2001-10-07 03:12:08 +00001121 The code and documentation for the derived OldProfile and HotProfile
1122 profiling classes was removed. The code hasn't worked for years (if
1123 you tried to use them, they raised exceptions). OldProfile
1124 intended to reproduce the behavior of the profiler Python used more
1125 than 7 years ago, and isn't interesting anymore. HotProfile intended
1126 to provide a faster profiler (but producing less information), and
1127 that's a worthy goal we intend to meet via a different approach (but
1128 without losing information).
1129
Tim Peterscce092d2001-10-09 05:31:56 +00001130- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +00001131 a much better system-specific calibration constant. The constant can
1132 now be specified in an instance constructor, or as a Profile class or
1133 instance variable, instead of by editing profile.py's source code.
1134 Calibration must still be done manually (see the docs for the profile
1135 module).
1136
1137 Note that Profile.calibrate() must be overriden by subclasses.
1138 Improving the accuracy required exploiting detailed knowledge of
1139 profiler internals; the earlier method abstracted away the details
1140 and measured a simplified model instead, but consequently computed
1141 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +00001142
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001143- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +00001144 which indicates whether output is intended for the header 'Q'
1145 encoding.
1146
Guido van Rossuma5343cc2001-10-18 18:02:07 +00001147- The SocketServer.ThreadingMixIn class now closes the request after
1148 finish_request() returns. (Not when it errors out though.)
1149
Barry Warsawf6fb1712001-10-19 05:35:40 +00001150- The nntplib module's NNTP.body() method has grown a `file' argument
1151 to allow saving the message body to a file.
1152
1153- The email package has added a class email.Parser.HeaderParser which
1154 only parses headers and does not recurse into the message's body.
1155 Also, the module/class MIMEAudio has been added for representing
1156 audio data (contributed by Anthony Baxter).
1157
1158- ftplib should be able to handle files > 2GB.
1159
1160- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
1161 ON, and OFF.
1162
Fred Drakecb7a6b52001-10-22 18:41:51 +00001163- xml.dom.minidom NodeList objects now support the length attribute
1164 and item() method as required by the DOM specifications.
1165
Guido van Rossumed554f62001-10-02 23:15:37 +00001166Tools/Demos
1167
1168- Demo/dns was removed. It no longer serves any purpose; a package
1169 derived from it is now maintained by Anthony Baxter, see
1170 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +00001171
Barry Warsawf6fb1712001-10-19 05:35:40 +00001172- The freeze tool has been made more robust, and two new options have
1173 been added: -X and -E.
1174
Tim Petersabf925f2001-09-28 21:53:42 +00001175Build
1176
Barry Warsawf6fb1712001-10-19 05:35:40 +00001177- configure will use CXX in LINKCC if CXX is used to build main() and
1178 the system requires to link a C++ main using the C++ compiler.
1179
Tim Petersabf925f2001-09-28 21:53:42 +00001180C API
1181
Guido van Rossum6c4bce32001-10-18 19:20:25 +00001182- The documentation for the tp_compare slot is updated to require that
1183 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
1184 not correct. This is not yet enforced but will be enforced in
1185 Python 2.3; even later, we may use -2 to indicate errors and +2 for
1186 "NotImplemented". Right now, -1 should be used for an error return.
1187
Tim Petersd38b1c72001-09-30 05:09:37 +00001188- PyLong_AsLongLong() now accepts int (as well as long) arguments.
1189 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
1190 as long) arguments.
1191
Guido van Rossum3c288632001-10-16 21:13:49 +00001192- PyThread_start_new_thread() now returns a long int giving the thread
1193 ID, if one can be calculated; it returns -1 for error, 0 if no
1194 thread ID is calculated (this is an incompatible change, but only
1195 the thread module used this API). This code has only really been
1196 tested on Linux and Windows; other platforms please beware (and
1197 report any bugs or strange behavior).
1198
Guido van Rossum1c486092001-10-19 02:05:35 +00001199- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
1200 input.
1201
Tim Petersabf925f2001-09-28 21:53:42 +00001202New platforms
1203
1204Tests
1205
1206Windows
1207
Tim Peters04cf1d32001-10-09 22:39:40 +00001208- Installer: If you install IDLE, and don't disable file-extension
1209 registration, a new "Edit with IDLE" context (right-click) menu entry
1210 is created for .py and .pyw files.
1211
Tim Peters1ce3cf72001-10-01 17:58:40 +00001212- The signal module now supports SIGBREAK on Windows, thanks to Steven
1213 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
1214 action remains to call Win32 ExitProcess(). This can be changed via
1215 signal.signal(). For example:
1216
1217 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
1218 # (SIGINT) behavior.
1219 import signal
1220 signal.signal(signal.SIGBREAK,
1221 signal.default_int_handler)
1222
1223 try:
1224 while 1:
1225 pass
1226 except KeyboardInterrupt:
1227 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
1228 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
1229 # program without the possibility for any Python-level cleanup).
1230 print "Clean exit"
1231
Tim Petersabf925f2001-09-28 21:53:42 +00001232
Tim Petersb07352e2001-09-08 01:25:47 +00001233What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001234Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +00001235===========================
1236
Guido van Rossum808eea72001-09-25 04:15:41 +00001237Type/class unification and new-style classes
1238
1239- pydoc and inspect are now aware of new-style classes;
1240 e.g. help(list) at the interactive prompt now shows proper
1241 documentation for all operations on list objects.
1242
1243- Applications using Jim Fulton's ExtensionClass module can now safely
1244 be used with Python 2.2. In particular, Zope 2.4.1 now works with
1245 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
1246 examples also work again. It is hoped that Gtk and Boost also work
1247 with 2.2a4 and beyond. (If you can confirm this, please write
1248 webmaster@python.org; if there are still problems, please open a bug
1249 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +00001250
Tim Peters66c1a522001-09-24 21:17:50 +00001251- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001252 These map to read-only attributes 'fget', 'fset', 'fdel', and '__doc__'
Tim Peters66c1a522001-09-24 21:17:50 +00001253 in the constructed property object. fget, fset and fdel weren't
1254 discoverable from Python in 2.2a3. __doc__ is new, and allows to
1255 associate a docstring with a property.
1256
Guido van Rossum808eea72001-09-25 04:15:41 +00001257- Comparison overloading is now more completely implemented. For
1258 example, a str subclass instance can properly be compared to a str
1259 instance, and it can properly overload comparison. Ditto for most
1260 other built-in object types.
1261
1262- The repr() of new-style classes has changed; instead of <type
1263 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
1264 *except* for built-in types, which are still rendered as <type
1265 'Foo'> (to avoid upsetting existing code that might parse or
1266 otherwise rely on repr() of certain type objects).
1267
1268- The repr() of new-style objects is now always <Foo object at XXX>;
1269 previously, it was sometimes <Foo instance at XXX>.
1270
1271- For new-style classes, what was previously called __getattr__ is now
1272 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001273 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +00001274 one in classic classes is defined which is called only if regular
1275 attribute access raises AttributeError; to catch *all* attribute
1276 access, you can use __getattribute__ (for new-style classes). If
1277 both are defined, __getattribute__ is called first, and if it raises
1278 AttributeError, __getattr__ is called.
1279
1280- The __class__ attribute of new-style objects can be assigned to.
1281 The new class must have the same C-level object layout as the old
1282 class.
1283
1284- The builtin file type can be subclassed now. In the usual pattern,
1285 "file" is the name of the builtin type, and file() is a new builtin
1286 constructor, with the same signature as the builtin open() function.
1287 file() is now the preferred way to open a file.
1288
1289- Previously, __new__ would only see sequential arguments passed to
1290 the type in a constructor call; __init__ would see both sequential
1291 and keyword arguments. This made no sense whatsoever any more, so
1292 now both __new__ and __init__ see all arguments.
1293
1294- Previously, hash() applied to an instance of a subclass of str or
1295 unicode always returned 0. This has been repaired.
1296
1297- Previously, an operation on an instance of a subclass of an
1298 immutable type (int, long, float, complex, tuple, str, unicode),
1299 where the subtype didn't override the operation (and so the
1300 operation was handled by the builtin type), could return that
1301 instance instead a value of the base type. For example, if s was of
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001302 a str subclass type, s[:] returned s as-is. Now it returns a str
Guido van Rossum808eea72001-09-25 04:15:41 +00001303 with the same value as s.
1304
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001305- Provisional support for pickling new-style objects has been added.
1306
Guido van Rossum808eea72001-09-25 04:15:41 +00001307Core
1308
Tim Peters2c9aa5e2001-09-23 04:06:05 +00001309- file.writelines() now accepts any iterable object producing strings.
1310
Marc-André Lemburgaefd7662001-09-20 12:59:37 +00001311- PyUnicode_FromEncodedObject() now works very much like
1312 PyObject_Str(obj) in that it tries to use __str__/tp_str
1313 on the object if the object is not a string or buffer. This
1314 makes unicode() behave like str() when applied to non-string/buffer
1315 objects.
1316
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001317- PyFile_WriteObject now passes Unicode objects to the file's write
1318 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +00001319 of a print statement must support Unicode objects, i.e. they must
1320 at least convert them into ASCII strings.
1321
Guido van Rossum624c8af2001-09-18 15:21:04 +00001322- Thread scheduling on Solaris should be improved; it is no longer
1323 necessary to insert a small sleep at the start of a thread in order
1324 to let other runnable threads be scheduled.
1325
Tim Petersb07352e2001-09-08 01:25:47 +00001326Library
1327
Marc-André Lemburgbf990172001-09-27 14:17:33 +00001328- StringIO.StringIO instances and cStringIO.StringIO instances support
1329 read character buffer compatible objects for their .write() methods.
1330 These objects are converted to strings and then handled as such
1331 by the instances.
1332
Barry Warsaw2f600732001-09-24 04:28:10 +00001333- The "email" package has been added. This is basically a port of the
1334 mimelib package <http://sf.net/projects/mimelib> with API changes
1335 and some implementations updated to use iterators and generators.
1336
Tim Peters8a9c2842001-09-22 21:30:22 +00001337- difflib.ndiff() and difflib.Differ.compare() are generators now. This
1338 restores the ability of Tools/scripts/ndiff.py to start producing output
1339 before the entire comparison is complete.
1340
Barry Warsaw58b072d2001-09-22 04:44:21 +00001341- StringIO.StringIO instances and cStringIO.StringIO instances support
1342 iteration just like file objects (i.e. their .readline() method is
1343 called for each iteration until it returns an empty string).
1344
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +00001345- The codecs module has grown four new helper APIs to access
1346 builtin codecs: getencoder(), getdecoder(), getreader(),
1347 getwriter().
1348
Guido van Rossum624c8af2001-09-18 15:21:04 +00001349- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
1350 simplifies writing XML RPC servers.
1351
Barry Warsaw647d5e82001-09-28 17:01:02 +00001352- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +00001353 after interpretation of symbolic links. On non-Unix systems, this
1354 is an alias for os.path.abspath().
1355
Tim Peters16a77ad2001-09-08 04:00:12 +00001356- operator.indexOf() (PySequence_Index() in the C API) now works with any
1357 iterable object.
1358
Guido van Rossum624c8af2001-09-18 15:21:04 +00001359- smtplib now supports various authentication and security features of
1360 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001361
Guido van Rossum624c8af2001-09-18 15:21:04 +00001362- hmac: a new module implementing keyed hashing for message
1363 authentication.
1364
1365- mimetypes now recognizes more extensions and file types. At the
1366 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001367
Guido van Rossum624c8af2001-09-18 15:21:04 +00001368- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001369 Python 2.2 bytecode generation. It has also been promoted from a
1370 Tool to a standard library package. (Tools/compiler still exists as
1371 a sample driver.)
1372
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001373Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +00001374
Tim Petersb07352e2001-09-08 01:25:47 +00001375Build
1376
Guido van Rossum624c8af2001-09-18 15:21:04 +00001377- Large file support (LFS) is now automatic when the platform supports
1378 it; no more manual configuration tweaks are needed. On Linux, at
1379 least, it's possible to have a system whose C library supports large
1380 files but whose kernel doesn't; in this case, large file support is
1381 still enabled but doesn't do you any good unless you upgrade your
1382 kernel or share your Python executable with another system whose
1383 kernel has large file support.
1384
1385- The configure script now supplies plausible defaults in a
1386 cross-compilation environment. This doesn't mean that the supplied
1387 values are always correct, or that cross-compilation now works
1388 flawlessly -- but it's a first step (and it shuts up most of
1389 autoconf's warnings about AC_TRY_RUN).
1390
1391- The Unix build is now a bit less chatty, courtesy of the parser
1392 generator. The build is completely silent (except for errors) when
1393 using "make -s", thanks to a -q option to setup.py.
1394
Tim Petersb07352e2001-09-08 01:25:47 +00001395C API
1396
Guido van Rossum624c8af2001-09-18 15:21:04 +00001397- The "structmember" API now supports some new flag bits to deny read
1398 and/or write access to attributes in restricted execution mode.
1399
Tim Petersb07352e2001-09-08 01:25:47 +00001400New platforms
1401
Guido van Rossum624c8af2001-09-18 15:21:04 +00001402- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1403 (http://familiar.handhelds.org).
1404
Tim Petersb07352e2001-09-08 01:25:47 +00001405Tests
1406
Tim Peters8a9c2842001-09-22 21:30:22 +00001407- The "classic" standard tests, which work by comparing stdout to
1408 an expected-output file under Lib/test/output/, no longer stop at
1409 the first mismatch. Instead the test is run to completion, and a
1410 variant of ndiff-style comparison is used to report all differences.
1411 This is much easier to understand than the previous style of reporting.
1412
1413- The unittest-based standard tests now use regrtest's test_main()
1414 convention, instead of running as a side-effect of merely being
1415 imported. This allows these tests to be run in more natural and
1416 flexible ways as unittests, outside the regrtest framework.
1417
1418- regrtest.py is much better integrated with unittest and doctest now,
1419 especially in regard to reporting errors.
1420
Tim Petersb07352e2001-09-08 01:25:47 +00001421Windows
1422
Guido van Rossum624c8af2001-09-18 15:21:04 +00001423- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001424 that support it (NTFS under Windows 2000). See "What's New in
1425 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001426
Tim Petersb07352e2001-09-08 01:25:47 +00001427
Tim Petersedc99312001-08-22 21:36:50 +00001428What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001429Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001430===========================
1431
1432Core
1433
Tim Peters9fffa3e2001-09-04 05:14:19 +00001434- Conversion of long to float now raises OverflowError if the long is too
1435 big to represent as a C double.
1436
Tim Peters32f453e2001-09-03 08:35:41 +00001437- The 3-argument builtin pow() no longer allows a third non-None argument
1438 if either of the first two arguments is a float, or if both are of
1439 integer types and the second argument is negative (in which latter case
1440 the arguments are converted to float, so this is really the same
1441 restriction).
1442
Tim Peters5d2b77c2001-09-03 05:47:38 +00001443- The builtin dir() now returns more information, and sometimes much
1444 more, generally naming all attributes of an object, and all attributes
1445 reachable from the object via its class, and from its class's base
1446 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1447 an empty list. In 2.2a3,
1448
1449 >>> dir([])
1450 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1451 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1452 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1453 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1454 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1455 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1456 'reverse', 'sort']
1457
1458 dir(module) continues to return only the module's attributes, though.
1459
Tim Petersbdee63f2001-09-02 03:40:59 +00001460- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001461 than raising OverflowError. This is a partial implementation of PEP
1462 237. You can use -Wdefault::OverflowWarning to enable a warning for
1463 this situation, and -Werror::OverflowWarning to revert to the old
1464 OverflowError exception.
1465
Guido van Rossum61c345f2001-09-04 03:26:15 +00001466- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001467 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001468 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1469 -Qold, meaning the / operator has its classic meaning and no
1470 warnings are issued. Using -Qwarn issues a run-time warning about
1471 all uses of classic division for int and long arguments; -Qwarnall
1472 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001473 (for use with fixdiv.py).
1474 [Note: the remainder of this paragraph (preserved below) became
1475 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1476 <obsolete>
1477 Using -Qnew is questionable; it turns on new division by default, but
1478 only in the __main__ module. You can usefully combine -Qwarn or
1479 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1480 warns about classic division everywhere else.
1481 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001482
Tim Petersbdee63f2001-09-02 03:40:59 +00001483- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001484 long, float, str, unicode, and tuple. (The types complex, list and
1485 dictionary can also be subclassed; this was introduced earlier.)
1486 Note that restrictions apply when subclassing immutable built-in
1487 types: you can only affect the value of the instance by overloading
1488 __new__. You can add mutable attributes, and the subclass instances
1489 will have a __dict__ attribute, but you cannot change the "value"
1490 (as implemented by the base class) of an immutable subclass instance
1491 once it is created.
1492
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001493- The dictionary constructor now takes an optional argument, a
1494 mapping-like object, and initializes the dictionary from its
1495 (key, value) pairs.
1496
Tim Petersbdee63f2001-09-02 03:40:59 +00001497- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001498 "cooperative super calls" in a multiple inheritance setting. For an
1499 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1500
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001501- A new built-in type, property, has been added. This enables the
1502 creation of "properties". These are attributes implemented by
1503 getter and setter functions (or only one of these for read-only or
1504 write-only attributes), without the need to override __getattr__.
1505 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001506
Tim Petersbdee63f2001-09-02 03:40:59 +00001507- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001508 liberalized, to allow leading zeroes. Examples of literals now
1509 legal that were SyntaxErrors before:
1510
1511 00.0 0e3 0100j 07.5 00000000000000000008.
1512
Tim Petersbdee63f2001-09-02 03:40:59 +00001513- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001514 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1515
Tim Petersedc99312001-08-22 21:36:50 +00001516Library
1517
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001518- telnetlib includes symbolic names for the options, and support for
1519 setting an option negotiation callback.
1520
Tim Petersa40c7932001-09-05 22:36:56 +00001521- The new C standard no longer requires that math libraries set errno to
1522 ERANGE on overflow. For platform libraries that exploit this new
1523 freedom, Python's overflow-checking was wholly broken. A new overflow-
1524 checking scheme attempts to repair that, but may not be reliable on all
1525 platforms (C doesn't seem to provide anything both useful and portable
1526 in this area anymore).
1527
Martin v. Löwis44f86962001-09-05 13:44:54 +00001528- Asynchronous timeout actions are available through the new class
1529 threading.Timer.
1530
Tim Peters78526162001-09-05 00:53:45 +00001531- math.log and math.log10 now return sensible results for even huge
1532 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1533
Tim Petersbdee63f2001-09-02 03:40:59 +00001534- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001535 currently held. See the docs for the imp module.
1536
Tim Petersbdee63f2001-09-02 03:40:59 +00001537- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001538 dumps containing ints written on platforms where Python ints are 8 bytes.
1539 When read on a box where Python ints are 4 bytes, such values are
1540 converted to Python longs.
1541
Tim Petersbdee63f2001-09-02 03:40:59 +00001542- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001543 code objects is no longer allowed. This plugs a security hole.
1544
Steve Purcell6091cd62001-09-06 16:05:17 +00001545- unittest.TestResult instances no longer store references to tracebacks
1546 generated by test failures. This prevents unexpected dangling references
1547 to objects that should be garbage collected between tests.
1548
Tim Petersedc99312001-08-22 21:36:50 +00001549Tools
1550
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001551- Tools/scripts/fixdiv.py has been added which can be used to fix
1552 division operators as per PEP 238.
1553
Tim Petersedc99312001-08-22 21:36:50 +00001554Build
1555
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001556- If you are an adventurous person using Mac OS X you may want to look at
1557 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1558 application, which can be used for experimenting with Carbon or Cocoa.
1559 Discussion of this on pythonmac-sig, please.
1560
Tim Peters7eea37e2001-09-04 22:08:56 +00001561C API
1562
1563- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001564
Tim Peters9fffa3e2001-09-04 05:14:19 +00001565- Note that PyLong_AsDouble can fail! This has always been true, but no
1566 callers checked for it. It's more likely to fail now, because overflow
1567 errors are properly detected now. The proper way to check:
1568
1569 double x = PyLong_AsDouble(some_long_object);
1570 if (x == -1.0 && PyErr_Occurred()) {
1571 /* The conversion failed. */
1572 }
1573
Tim Petersbdee63f2001-09-02 03:40:59 +00001574- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001575 compile but will not participate in GC. To upgrade an extension
1576 module:
1577
1578 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001579
Neil Schemenauer4042c692001-08-30 15:38:01 +00001580 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1581 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001582
Neil Schemenauer4042c692001-08-30 15:38:01 +00001583 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1584 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001585
Neil Schemenauer4042c692001-08-30 15:38:01 +00001586 - remove PyGC_HEAD_SIZE from object size calculations
1587
1588 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1589
Tim Petersbdee63f2001-09-02 03:40:59 +00001590- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001591 These can be used safely to construct string objects from a
1592 sprintf-style format string (similar to the format string supported
1593 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001594
Tim Petersedc99312001-08-22 21:36:50 +00001595New platforms
1596
Tim Petersb7da0902001-09-02 23:01:43 +00001597- Stephen Hansen contributed patches sufficient to get a clean compile
1598 under Borland C (Windows), but he reports problems running it and ran
1599 out of time to complete the port. Volunteers? Expect a MemoryError
1600 when importing the types module; this is probably shallow, and
1601 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001602
Tim Petersedc99312001-08-22 21:36:50 +00001603Tests
1604
1605Windows
1606
Tim Peters6e13a562001-09-06 00:32:15 +00001607- Large file support is now enabled on Win32 platforms as well as on
1608 Win64. This means that, for example, you can use f.tell() and f.seek()
1609 to manipulate files larger than 2 gigabytes (provided you have enough
1610 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001611 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1612 filesize limit, and large file support makes no difference there.
1613 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1614 NTFS has no practical limit on file size, and files of any size can be
1615 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001616
Tim Petersbdee63f2001-09-02 03:40:59 +00001617- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001618 points to command.com (patch from Brian Quinlan).
1619
Tim Petersedc99312001-08-22 21:36:50 +00001620
Tim Peters20f51a72001-07-21 02:31:40 +00001621What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001622Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001623===========================
1624
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001625Build
1626
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001627- Tim Peters developed a brand new Windows installer using Wise 8.1,
1628 generously donated to us by Wise Solutions.
1629
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001630- configure supports a new option --enable-unicode, with the values
1631 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1632 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001633
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001634- A new configure option --enable-framework builds a Mac OS X framework,
1635 which "make frameworkinstall" will install. This provides a starting
1636 point for more mac-like functionality, join pythonmac-sig@python.org
1637 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001638
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001639- The NeXT platform is no longer supported.
1640
1641- The `new' module is now statically linked.
1642
Tim Peters0afb6092001-08-15 06:06:44 +00001643Tools
1644
1645- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001646 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001647 the module docstring for details.
1648
Tim Peters20f51a72001-07-21 02:31:40 +00001649Tests
1650
Tim Peters5e824c32001-08-12 22:25:01 +00001651- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001652 platforms, allowing to give clearer test result output. regrtest
1653 also has optional --use/-u switch to run normally disabled tests
1654 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001655
Tim Peters20f51a72001-07-21 02:31:40 +00001656- Several new tests in the standard test suite, with special thanks to
1657 Nick Mathewson.
1658
1659Core
1660
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001661- The floor division operator // has been added as outlined in PEP
1662 238. The / operator still provides classic division (and will until
1663 Python 3.0) unless "from __future__ import division" is included, in
1664 which case the / operator will provide true division. The operator
1665 module provides truediv() and floordiv() functions. Augmented
1666 assignment variants are included, as are the equivalent overloadable
1667 methods and C API methods. See the PEP for a full discussion:
1668 <http://python.sf.net/peps/pep-0238.html>
1669
Tim Peters6cd6a822001-08-17 22:11:27 +00001670- Future statements are now effective in simulated interactive shells
1671 (like IDLE). This should "just work" by magic, but read Michael
1672 Hudson's "Future statements in simulated shells" PEP 264 for full
1673 details: <http://python.sf.net/peps/pep-0264.html>.
1674
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001675- The type/class unification (PEP 252-253) was integrated into the
1676 trunk and is not so tentative any more (the exact specification of
1677 some features is still tentative). A lot of work has done on fixing
1678 bugs and adding robustness and features (performance still has to
1679 come a long way).
1680
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001681- Warnings about a mismatch in the Python API during extension import
1682 now use the Python warning framework (which makes it possible to
1683 write filters for these warnings).
1684
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001685- A function's __dict__ (aka func_dict) will now always be a
1686 dictionary. It used to be possible to delete it or set it to None,
1687 but now both actions raise TypeErrors. It is still legal to set it
1688 to a dictionary object. Getting func.__dict__ before any attributes
1689 have been assigned now returns an empty dictionary instead of None.
1690
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001691- A new command line option, -E, was added which disables the use of
1692 all environment variables, or at least those that are specifically
1693 significant to Python. Usually those have a name starting with
1694 "PYTHON". This was used to fix a problem where the tests fail if
1695 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1696 older distribution.
1697
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001698Library
1699
Tim Peters5e824c32001-08-12 22:25:01 +00001700- New class Differ and new functions ndiff() and restore() in difflib.py.
1701 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001702 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001703
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001704- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1705 value using the minimal quoting required for the value; more
1706 reliable than using xml.sax.saxutils.escape() for attribute values.
1707
1708- Readline completion support for cmd.Cmd was added.
1709
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001710- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1711
1712- Added function threading.BoundedSemaphore()
1713
1714- Added Ka-Ping Yee's cgitb.py module.
1715
1716- The `new' module now exposes the CO_xxx flags.
1717
Martin v. Löwis560da622001-11-24 09:24:51 +00001718- The gc module offers the get_referents function.
1719
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001720New platforms
1721
1722C API
1723
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001724- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1725 which provide a cross-platform implementations for the
1726 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1727 the standard sprintf() and vsprintf() C lib APIs, these versions
1728 apply bounds checking on the used buffer which enhances protection
1729 against buffer overruns.
1730
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001731- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001732 and extensions using different Unicode widths is rendered next to
1733 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001734 will result in an ImportError. Unicode extensions writers must make
1735 sure to check the Unicode width compatibility in their extensions by
1736 using at least one of the mangled Unicode APIs in the extension.
1737
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001738- Two new flags METH_NOARGS and METH_O are available in method definition
1739 tables to simplify implementation of methods with no arguments and a
1740 single untyped argument. Calling such methods is more efficient than
1741 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1742 deprecated.
1743
Tim Petersc1731372001-08-04 08:12:36 +00001744Windows
1745
1746- "import module" now compiles module.pyw if it exists and nothing else
1747 relevant is found.
1748
Tim Peters20f51a72001-07-21 02:31:40 +00001749
Guido van Rossum55a78992001-07-17 17:22:32 +00001750What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001751Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001752===========================
1753
1754Core
Tim Petersa814db52001-05-14 07:05:58 +00001755
Tim Peters6d6c1a32001-08-02 04:15:00 +00001756- TENTATIVELY, a large amount of code implementing much of what's
1757 described in PEP 252 (Making Types Look More Like Classes) and PEP
1758 253 (Subtyping Built-in Types) was added. This will be released
1759 with Python 2.2a1. Documentation will be provided separately
1760 through http://www.python.org/2.2/. The purpose of releasing this
1761 with Python 2.2a1 is to test backwards compatibility. It is
1762 possible, though not likely, that a decision is made not to release
1763 this code as part of 2.2 final, if any serious backwards
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00001764 incompatibilities are found during alpha testing that cannot be
Tim Peters6d6c1a32001-08-02 04:15:00 +00001765 repaired.
1766
Guido van Rossum55a78992001-07-17 17:22:32 +00001767- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001768 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001769 more 'yield' statements. See PEP 255. Since this adds a new
1770 keyword to the language, this feature must be enabled by including a
1771 future statement: "from __future__ import generators" (see PEP 236).
1772 Generators will become a standard feature in a future release
1773 (probably 2.3). Without this future statement, 'yield' remains an
1774 ordinary identifier, but a warning is issued each time it is used.
1775 (These warnings currently don't conform to the warnings framework of
1776 PEP 230; we intend to fix this in 2.2a2.)
1777
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001778- The UTF-16 codec was modified to be more RFC compliant. It will now
1779 only remove BOM characters at the start of the string and then
1780 only if running in native mode (UTF-16-LE and -BE won't remove a
1781 leading BMO character).
1782
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001783- Strings now have a new method .decode() to complement the already
1784 existing .encode() method. These two methods provide direct access
1785 to the corresponding decoders and encoders of the registered codecs.
1786
1787 To enhance the usability of the .encode() method, the special
1788 casing of Unicode object return values was dropped (Unicode objects
1789 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001790
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001791 Both methods will now return whatever the codec in charge of the
1792 requested encoding returns as object, e.g. Unicode codecs will
1793 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1794 will return u"äöü"). This enables codec writer to create codecs
1795 for various simple to use conversions.
1796
1797 New codecs were added to demonstrate these new features (the .encode()
1798 and .decode() columns indicate the type of the returned objects):
1799
1800 Name | .encode() | .decode() | Description
1801 ----------------------------------------------------------------------
1802 uu | string | string | UU codec (e.g. for email)
1803 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001804 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001805 zlib | string | string | zlib compression
1806 hex | string | string | 2-byte hex codec
1807 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1808
Mark Hammond2a0af792001-05-14 03:09:36 +00001809- Some operating systems now support the concept of a default Unicode
1810 encoding for file system operations. Notably, Windows supports 'mbcs'
1811 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001812 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001813 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001814
1815 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001816 functions that return filenames (such as os.listdir()) to return Python
1817 string objects pre-encoded using the default file system encoding for
1818 the platform. As this encoding is likely to be different from Python's
1819 default encoding, converting this name to a Unicode object before passing
1820 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001821 would attempt to use its default encoding (generally ASCII) rather than
1822 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001823
Tim Petersa814db52001-05-14 07:05:58 +00001824 In general, this change simply removes surprises when working with
1825 Unicode and the file system, making these operations work as you expect,
1826 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001827 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001828
Tim Peters61dff2b2001-05-08 15:43:37 +00001829- Float (and complex) literals in source code were evaluated to full
1830 precision only when running from a .py file; the same code loaded from a
1831 .pyc (or .pyo) file could suffer numeric differences starting at about the
1832 12th significant decimal digit. For example, on a machine with IEEE-754
1833 floating arithmetic,
1834
1835 x = 9007199254740992.0
1836 print long(x)
1837
1838 printed 9007199254740992 if run directly from .py, but 9007199254740000
1839 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1840 str(float) instead of repr(float) when building code objects. marshal
1841 now uses repr(float) instead, which should reproduce floats to full
1842 machine precision (assuming the platform C float<->string I/O conversion
1843 functions are of good quality).
1844
1845 This may cause floating-point results to change in some cases, and
1846 usually for the better, but may also cause numerically unstable
1847 algorithms to break.
1848
Tim Peters2f228e72001-05-13 00:19:31 +00001849- The implementation of dicts suffers fewer collisions, which has speed
1850 benefits. However, the order in which dict entries appear in dict.keys(),
1851 dict.values() and dict.items() may differ from previous releases for a
1852 given dict. Nothing is defined about this order, so no program should
1853 rely on it. Nevertheless, it's easy to write test cases that rely on the
1854 order by accident, typically because of printing the str() or repr() of a
1855 dict to an "expected results" file. See Lib/test/test_support.py's new
1856 sortdict(dict) function for a simple way to display a dict in sorted
1857 order.
1858
Tim Peters7a3bfc32001-06-12 01:22:22 +00001859- Many other small changes to dicts were made, resulting in faster
1860 operation along the most common code paths.
1861
Guido van Rossum10315822001-05-01 20:54:30 +00001862- Dictionary objects now support the "in" operator: "x in dict" means
1863 the same as dict.has_key(x).
1864
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001865- The update() method of dictionaries now accepts generic mapping
1866 objects. Specifically the argument object must support the .keys()
1867 and __getitem__() methods. This allows you to say, for example,
1868 {}.update(UserDict())
1869
Guido van Rossum10315822001-05-01 20:54:30 +00001870- Iterators were added; this is a generalized way of providing values
1871 to a for loop. See PEP 234. There's a new built-in function iter()
1872 to return an iterator. There's a new protocol to get the next value
1873 from an iterator using the next() method (in Python) or the
1874 tp_iternext slot (in C). There's a new protocol to get iterators
1875 using the __iter__() method (in Python) or the tp_iter slot (in C).
1876 Iterating (i.e. a for loop) over a dictionary generates its keys.
1877 Iterating over a file generates its lines.
1878
Tim Petersf553f892001-05-01 20:45:31 +00001879- The following functions were generalized to work nicely with iterator
1880 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001881 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001882 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1883 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001884 join() method of strings
1885 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001886 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1887 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001888 right-hand side of assignment statements with multiple targets, such as
1889 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001890
Tim Petersd85e1022001-05-11 21:51:48 +00001891- Accessing module attributes is significantly faster (for example,
1892 random.random or os.path or yourPythonModule.yourAttribute).
1893
Tim Peterse63415e2001-05-08 04:38:29 +00001894- Comparing dictionary objects via == and != is faster, and now works even
1895 if the keys and values don't support comparisons other than ==.
1896
Tim Peters95bf9392001-05-10 08:32:44 +00001897- Comparing dictionaries in ways other than == and != is slower: there were
1898 insecurities in the dict comparison implementation that could cause Python
1899 to crash if the element comparison routines for the dict keys and/or
1900 values mutated the dicts. Making the code bulletproof slowed it down.
1901
Tim Peterseb28ef22001-06-02 05:27:19 +00001902- Collisions in dicts are resolved via a new approach, which can help
1903 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001904 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001905 faster now. Thanks to Christian Tismer for pointing out the cause and
1906 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001907
Tim Peters52e155e2001-06-16 05:42:57 +00001908- repr() is much faster for large containers (dict, list, tuple).
1909
1910
Tim Petersa814db52001-05-14 07:05:58 +00001911Library
1912
Fred Drake960fdf92001-07-20 18:38:26 +00001913- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00001914 were added to the string module. These a locale-independent
Fred Drake960fdf92001-07-20 18:38:26 +00001915 constants, unlike letters, lowercase, and uppercase. These are now
1916 use in appropriate locations in the standard library.
1917
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001918- The flags used in dlopen calls can now be configured using
1919 sys.setdlopenflags and queried using sys.getdlopenflags.
1920
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001921- Fredrik Lundh's xmlrpclib is now a standard library module. This
1922 provides full client-side XML-RPC support. In addition,
1923 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1924 one asyncore-based). Thanks to Eric Raymond for the documentation.
1925
Guido van Rossum643d3912001-07-05 14:46:25 +00001926- The xrange() object is simplified: it no longer supports slicing,
1927 repetition, comparisons, efficient 'in' checking, the tolist()
1928 method, or the start, stop and step attributes. See PEP 260.
1929
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001930- A new function fnmatch.filter to filter lists of file names was added.
1931
Barry Warsawffd674d2001-05-22 16:00:10 +00001932- calendar.py uses month and day names based on the current locale.
1933
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001934- strop is now *really* obsolete (this was announced before with 1.6),
1935 and issues DeprecationWarning when used (except for the four items
1936 that are still imported into string.py).
1937
Tim Petersa814db52001-05-14 07:05:58 +00001938- Cookie.py now sorts key+value pairs by key in output strings.
1939
1940- pprint.isrecursive(object) didn't correctly identify recursive objects.
1941 Now it does.
1942
Tim Peters95b3f782001-05-14 18:39:41 +00001943- pprint functions now much faster for large containers (tuple, list, dict).
1944
Tim Peters7b9542a2001-06-10 23:40:19 +00001945- New 'q' and 'Q' format codes in the struct module, corresponding to C
1946 types "long long" and "unsigned long long" (on Windows, __int64). In
1947 native mode, these can be used only when the platform C compiler supports
1948 these types (when HAVE_LONG_LONG is #define'd by the Python config
1949 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001950 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1951 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001952
Guido van Rossum83213cc2001-06-12 16:48:52 +00001953- The site module installs a new built-in function 'help' that invokes
1954 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1955 it displays a message reminding the user to use 'help()' or
1956 'help(object)'.
1957
Tim Petersa814db52001-05-14 07:05:58 +00001958Tests
1959
1960- New test_mutants.py runs dict comparisons where the key and value
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00001961 comparison operators mutate the dicts randomly during comparison. This
Tim Petersa814db52001-05-14 07:05:58 +00001962 rapidly causes Python to crash under earlier releases (not for the faint
1963 of heart: it can also cause Win9x to freeze or reboot!).
1964
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00001965- New test_pprint.py verifies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001966 pprint.isreadable() return sensible results. Also verifies that simple
1967 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001968
Tim Peters4324aa32001-05-28 22:30:08 +00001969C API
1970
1971- Removed the unused last_is_sticky argument from the internal
1972 _PyTuple_Resize(). If this affects you, you were cheating.
1973
1974
Guido van Rossum55a78992001-07-17 17:22:32 +00001975======================================================================
1976
1977
Guido van Rossumffe13be2001-04-16 18:46:45 +00001978What's New in Python 2.1 (final)?
1979=================================
1980
1981We only changed a few things since the last release candidate, all in
1982Python library code:
1983
1984- A bug in the locale module was fixed that affected locales which
1985 define no grouping for numeric formatting.
1986
1987- A few bugs in the weakref module's implementations of weak
1988 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1989 and the test suite was updated to check for these bugs.
1990
1991- An old bug in the os.path.walk() function (introduced in Python
1992 2.0!) was fixed: a non-existent file would cause an exception
1993 instead of being ignored.
1994
1995- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1996 PyChecker.
1997
1998
Guido van Rossum5b08f132001-04-16 02:05:23 +00001999What's New in Python 2.1c2?
2000===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00002001
Guido van Rossum5b08f132001-04-16 02:05:23 +00002002A flurry of small changes, and one showstopper fixed in the nick of
2003time made it necessary to release another release candidate. The list
2004here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00002005
Guido van Rossum5b08f132001-04-16 02:05:23 +00002006Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00002007
Guido van Rossum5b08f132001-04-16 02:05:23 +00002008- Tim discovered a nasty bug in the dictionary code, caused by
2009 PyDict_Next() calling dict_resize(), and the GC code's use of
2010 PyDict_Next() violating an assumption in dict_items(). This was
2011 fixed with considerable amounts of band-aid, but the net effect is a
2012 saner and more robust implementation.
2013
2014- Made a bunch of symbols static that were accidentally global.
2015
2016Build and Ports
2017
2018- The setup.py script didn't check for a new enough version of zlib
2019 (1.1.3 is needed). Now it does.
2020
2021- Changed "make clean" target to also remove shared libraries.
2022
2023- Added a more general warning about the SGI Irix optimizer to README.
2024
2025Library
2026
2027- Fix a bug in urllib.basejoin("http://host", "../file.html") which
2028 omitted the slash between host and file.html.
2029
2030- The mailbox module's _Mailbox class contained a completely broken
2031 and undocumented seek() method. Ripped it out.
2032
2033- Fixed a bunch of typos in various library modules (urllib2, smtpd,
2034 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
2035
2036- Fixed a few last-minute bugs in unittest.
2037
2038Extensions
2039
2040- Reverted the patch to the OpenSSL code in socketmodule.c to support
2041 RAND_status() and the EGD, and the subsequent patch that tried to
2042 fix it for pre-0.9.5 versions; the problem with the patch is that on
2043 some systems it issues a warning whenever socket is imported, and
2044 that's unacceptable.
2045
2046Tests
2047
2048- Fixed the pickle tests to work with "import test.test_pickle".
2049
2050- Tweaked test_locale.py to actually run the test Windows.
2051
2052- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
2053 not "wb" (which is not a valid mode at all).
2054
2055- Fix pstats browser crashes. Import readline if it exists to make
2056 the user interface nicer.
2057
2058- Add "import thread" to the top of test modules that import the
2059 threading module (test_asynchat and test_threadedtempfile). This
2060 prevents test failures caused by a broken threading module resulting
2061 from a previously caught failed import.
2062
2063- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
2064 needed on some platforms (e.g. Solaris 8) when the tests are run
2065 twice in succession.
2066
2067- Skip rather than fail test_sunaudiodev if no audio device is found.
2068
2069
2070What's New in Python 2.1c1?
2071===========================
2072
2073This list was significantly updated when 2.1c2 was released; the 2.1c1
2074release didn't mention most changes that were actually part of 2.1c1:
2075
2076Legal
2077
2078- Copyright was assigned to the Python Software Foundation (PSF) and a
2079 PSF license (very similar to the CNRI license) was added.
2080
2081- The CNRI copyright notice was updated to include 2001.
2082
2083Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00002084
Guido van Rossumc9932722001-04-12 02:31:27 +00002085- After a public outcry, assignment to __debug__ is no longer illegal;
2086 instead, a warning is issued. It will become illegal in 2.2.
2087
Guido van Rossum5b08f132001-04-16 02:05:23 +00002088- Fixed a core dump with "%#x" % 0, and changed the semantics so that
2089 "%#x" now always prepends "0x", even if the value is zero.
2090
2091- Fixed some nits in the bytecode compiler.
2092
2093- Fixed core dumps when calling certain kinds of non-functions.
2094
2095- Fixed various core dumps caused by reference count bugs.
2096
2097Build and Ports
2098
2099- Use INSTALL_SCRIPT to install script files.
2100
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002101- New port: SCO Unixware 7, by Billy G. Allie.
2102
Guido van Rossum5b08f132001-04-16 02:05:23 +00002103- Updated RISCOS port.
2104
2105- Updated BeOS port and notes.
2106
2107- Various other porting problems resolved.
2108
2109Library
2110
2111- The TERMIOS and SOCKET modules are now truly obsolete and
2112 unnecessary. Their symbols are incorporated in the termios and
2113 socket modules.
2114
2115- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
2116 better tests for pickling.
2117
2118- threading: make Condition.wait() robust against KeyboardInterrupt.
2119
2120- zipfile: add support to zipfile to support opening an archive
2121 represented by an open file rather than a file name. Fix bug where
2122 the archive was not properly closed. Fixed a bug in this bugfix
2123 where flush() was called for a read-only file.
2124
2125- imputil: added an uninstall() method to the ImportManager.
2126
2127- Canvas: fixed bugs in lower() and tkraise() methods.
2128
2129- SocketServer: API change (added overridable close_request() method)
2130 so that the TCP server can explicitly close the request.
2131
2132- pstats: Eric Raymond added a simple interactive statistics browser,
2133 invoked when the module is run as a script.
2134
2135- locale: fixed a problem in format().
2136
2137- webbrowser: made it work when the BROWSER environment variable has a
2138 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
2139 KDE 2. Fixed some other nits.
2140
2141- unittest: changes to allow using a different exception than
2142 AssertionError, and added a few more function aliases. Some other
2143 small changes.
2144
2145- urllib, urllib2: fixed redirect problems and a coupleof other nits.
2146
2147- asynchat: fixed a critical bug in asynchat that slipped through the
2148 2.1b2 release. Fixed another rare bug.
2149
2150- Fix some unqualified except: clauses (always a bad code example).
2151
2152XML
2153
2154- pyexpat: new API get_version_string().
2155
2156- Fixed some minidom bugs.
2157
2158Extensions
2159
2160- Fixed a core dump in _weakref. Removed the weakref.mapping()
2161 function (it adds nothing to the API).
2162
2163- Rationalized the use of header files in the readline module, to make
2164 it compile (albeit with some warnings) with the very recent readline
2165 4.2, without breaking for earlier versions.
2166
2167- Hopefully fixed a buffering problem in linuxaudiodev.
2168
2169- Attempted a fix to make the OpenSSL support in the socket module
2170 work again with pre-0.9.5 versions of OpenSSL.
2171
2172Tests
2173
2174- Added a test case for asynchat and asyncore.
2175
2176- Removed coupling between tests where one test failing could break
2177 another.
2178
2179Tools
2180
2181- Ping added an interactive help browser to pydoc, fixed some nits
2182 in the rest of the pydoc code, and added some features to his
2183 inspect module.
2184
2185- An updated python-mode.el version 4.1 which integrates Ken
2186 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
2187 much nicer in XEmacs and Emacs. When stepping through your program
2188 with pdb, in either the shell window or the *Python* window, the
2189 source file and line will be tracked by an arrow. Very cool!
2190
2191- IDLE: syntax warnings in interactive mode are changed into errors.
2192
2193- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00002194 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00002195
2196- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002197
Barry Warsaw11e89c72001-04-11 20:37:57 +00002198
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002199What's New in Python 2.1 beta 2?
2200================================
2201
Guido van Rossum053ae352001-03-22 14:17:21 +00002202(Unlisted are many fixed bugs, more documentation, etc.)
2203
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002204Core language, builtins, and interpreter
2205
Guido van Rossum053ae352001-03-22 14:17:21 +00002206- The nested scopes work (enabled by "from __future__ import
2207 nested_scopes") is completed; in particular, the future now extends
2208 into code executed through exec, eval() and execfile(), and into the
2209 interactive interpreter.
2210
2211- When calling a base class method (e.g. BaseClass.__init__(self)),
2212 this is now allowed even if self is not strictly spoken a class
2213 instance (e.g. when using metaclasses or the Don Beaudry hook).
2214
2215- Slice objects are now comparable but not hashable; this prevents
2216 dict[:] from being accepted but meaningless.
2217
2218- Complex division is now calculated using less braindead algorithms.
2219 This doesn't change semantics except it's more likely to give useful
2220 results in extreme cases. Complex repr() now uses full precision
2221 like float repr().
2222
2223- sgmllib.py now calls handle_decl() for simple <!...> declarations.
2224
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002225- It is illegal to assign to the name __debug__, which is set when the
2226 interpreter starts. It is effectively a compile-time constant.
2227
2228- A warning will be issued if a global statement for a variable
2229 follows a use or assignment of that variable.
2230
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002231Standard library
2232
Guido van Rossum053ae352001-03-22 14:17:21 +00002233- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
2234 inspired by JUnit), is now part of the standard library. You now
2235 have a choice of two testing frameworks: unittest requires you to
2236 write testcases as separate code, doctest gathers them from
2237 docstrings. Both approaches have their advantages and
2238 disadvantages.
2239
2240- A new module Tix was added, which wraps the Tix extension library
2241 for Tk. With that module, it is not necessary to statically link
2242 Tix with _tkinter, since Tix will be loaded with Tcl's "package
2243 require" command. See Demo/tix/.
2244
2245- tzparse.py is now obsolete.
2246
2247- In gzip.py, the seek() and tell() methods are removed -- they were
2248 non-functional anyway, and it's better if callers can test for their
2249 existence with hasattr().
2250
2251Python/C API
2252
2253- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
2254 that's already in the dictionary during a PyDict_Next() iteration.
2255 This used to fail occasionally when a dictionary resize operation
2256 could be triggered that would rehash all the keys. All other
2257 modifications to the dictionary are still off-limits during a
2258 PyDict_Next() iteration!
2259
2260- New extended APIs related to passing compiler variables around.
2261
2262- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
2263 implement isinstance() and issubclass().
2264
2265- Py_BuildValue() now has a "D" conversion to create a Python complex
2266 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002267
Fred Drake4e262a92001-03-22 18:26:47 +00002268- Extensions types which support weak references must now set the
2269 field allocated for the weak reference machinery to NULL themselves;
2270 this is done to avoid the cost of checking each object for having a
2271 weakly referencable type in PyObject_INIT(), since most types are
2272 not weakly referencable.
2273
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002274- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
2275 free variables and cell variables to and from the frame's f_locals.
2276
2277- Variants of several functions defined in pythonrun.h have been added
2278 to support the nested_scopes future statement. The variants all end
2279 in Flags and take an extra argument, a PyCompilerFlags *; examples:
2280 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
2281 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00002282 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002283
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002284Distutils
2285
2286- the sdist command now writes a PKG-INFO file, as described in PEP 241,
2287 into the release tree.
2288
Tim Peters0e57abf2001-05-02 07:39:38 +00002289- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002290 (an uninstaller, more customization of the installer's display)
2291
2292- from Jack Jansen: added Mac-specific code to generate a dialog for
2293 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00002294 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002295 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00002296
2297- added 'platforms' and 'keywords' to the set of metadata that can be
2298 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002299
2300- applied patches from Jason Tishler to make the compiler class work with
2301 Cygwin.
2302
2303
Tim Peters2fe289a2001-03-01 22:19:38 +00002304What's New in Python 2.1 beta 1?
2305================================
Tim Petersd66595f2001-02-04 03:09:53 +00002306
2307Core language, builtins, and interpreter
2308
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00002309- Following an outcry from the community about the amount of code
2310 broken by the nested scopes feature introduced in 2.1a2, we decided
2311 to make this feature optional, and to wait until Python 2.2 (or at
2312 least 6 months) to make it standard. The option can be enabled on a
2313 per-module basis by adding "from __future__ import nested_scopes" at
2314 the beginning of a module (before any other statements, but after
2315 comments and an optional docstring). See PEP 236 (Back to the
2316 __future__) for a description of the __future__ statement. PEP 227
2317 (Statically Nested Scopes) has been updated to reflect this change,
2318 and to clarify the semantics in a number of endcases.
2319
2320- The nested scopes code, when enabled, has been hardened, and most
2321 bugs and memory leaks in it have been fixed.
2322
2323- Compile-time warnings are now generated for a number of conditions
2324 that will break or change in meaning when nested scopes are enabled:
2325
2326 - Using "from...import *" or "exec" without in-clause in a function
2327 scope that also defines a lambda or nested function with one or
2328 more free (non-local) variables. The presence of the import* or
2329 bare exec makes it impossible for the compiler to determine the
2330 exact set of local variables in the outer scope, which makes it
2331 impossible to determine the bindings for free variables in the
2332 inner scope. To avoid the warning about import *, change it into
2333 an import of explicitly name object, or move the import* statement
2334 to the global scope; to avoid the warning about bare exec, use
2335 exec...in... (a good idea anyway -- there's a possibility that
2336 bare exec will be deprecated in the future).
2337
2338 - Use of a global variable in a nested scope with the same name as a
2339 local variable in a surrounding scope. This will change in
2340 meaning with nested scopes: the name in the inner scope will
2341 reference the variable in the outer scope rather than the global
2342 of the same name. To avoid the warning, either rename the outer
2343 variable, or use a global statement in the inner function.
2344
Neil Schemenauera35c6882001-02-27 04:45:05 +00002345- An optional object allocator has been included. This allocator is
2346 optimized for Python objects and should be faster and use less memory
2347 than the standard system allocator. It is not enabled by default
2348 because of possible thread safety problems. The allocator is only
2349 protected by the Python interpreter lock and it is possible that some
2350 extension modules require a thread safe allocator. The object
2351 allocator can be enabled by providing the "--with-pymalloc" option to
2352 configure.
2353
Tim Petersd66595f2001-02-04 03:09:53 +00002354Standard library
2355
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002356- pyexpat now detects the expat version if expat.h defines it. A
2357 number of additional handlers are provided, which are only available
2358 since expat 1.95. In addition, the methods SetParamEntityParsing and
2359 GetInputContext of Parser objects are available with 1.95.x
2360 only. Parser objects now provide the ordered_attributes and
2361 specified_attributes attributes. A new module expat.model was added,
2362 which offers a number of additional constants if 1.95.x is used.
2363
2364- xml.dom offers the new functions registerDOMImplementation and
2365 getDOMImplementation.
2366
2367- xml.dom.minidom offers a toprettyxml method. A number of DOM
2368 conformance issues have been resolved. In particular, Element now
2369 has an hasAttributes method, and the handling of namespaces was
2370 improved.
2371
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002372- Ka-Ping Yee contributed two new modules: inspect.py, a module for
2373 getting information about live Python code, and pydoc.py, a module
2374 for interactively converting docstrings to HTML or text.
2375 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002376 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002377 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2378 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002379
Tim Peters1eff7962001-03-01 02:31:33 +00002380- New library module difflib.py, primarily packaging the SequenceMatcher
2381 class at the heart of the popular ndiff.py file-comparison tool.
2382
2383- doctest.py (a framework for verifying Python code examples in docstrings)
2384 is now part of the std library.
2385
Tim Petersd66595f2001-02-04 03:09:53 +00002386Windows changes
2387
Guido van Rossume3955a82001-03-02 14:05:59 +00002388- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2389 small GUI that lets you browse the module docstrings using your
2390 default web browser.
2391
Tim Peters1eff7962001-03-01 02:31:33 +00002392- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2393 Platforms) is implemented. See
2394
2395 http://python.sourceforge.net/peps/pep-0235.html
2396
2397 for full details, especially the "Current Lower-Left Semantics" section.
2398 The new Windows import rules are simpler than before:
2399
2400 A. If the PYTHONCASEOK environment variable exists, same as
2401 before: silently accept the first case-insensitive match of any
2402 kind; raise ImportError if none found.
2403
2404 B. Else search sys.path for the first case-sensitive match; raise
2405 ImportError if none found.
2406
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002407 The same rules have been implemented on other platforms with case-
Tim Peters1eff7962001-03-01 02:31:33 +00002408 insensitive but case-preserving filesystems too (including Cygwin, and
2409 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002410
Tim Peters25a9ce32001-02-19 07:06:36 +00002411- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2412 what it's supposed to do (and does do under NT and 2000) via direct
2413 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002414 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002415 all Win9x systems before.
2416
Tim Peters1eff7962001-03-01 02:31:33 +00002417- Build: Subproject _test (effectively) renamed to _testcapi.
2418
Tim Peters2fe289a2001-03-01 22:19:38 +00002419New platforms
2420
2421- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2422 Thanks to Steven Majewski!
2423
2424- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2425 Tishler!
2426
Guido van Rossum9089b272001-03-02 06:49:50 +00002427- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2428 Schwertberger! See RISCOS/README for more information -- it seems
2429 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002430 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002431
Tim Peters25a9ce32001-02-19 07:06:36 +00002432
Tim Petersd7b5e882001-01-25 03:36:26 +00002433What's New in Python 2.1 alpha 2?
2434=================================
Tim Peters40ead762001-01-27 05:35:26 +00002435
Tim Petersd7b5e882001-01-25 03:36:26 +00002436Core language, builtins, and interpreter
2437
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002438- Scopes nest. If a name is used in a function or class, but is not
2439 local, the definition in the nearest enclosing function scope will
2440 be used. One consequence of this change is that lambda statements
2441 could reference variables in the namespaces where the lambda is
2442 defined. In some unusual cases, this change will break code.
2443
2444 In all previous version of Python, names were resolved in exactly
2445 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002446 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002447 function A is defined within a function B, the names bound in B are
2448 not visible in A. The new rules make names bound in B visible in A,
2449 unless A contains a name binding that hides the binding in B.
2450
2451 Section 4.1 of the reference manual describes the new scoping rules
2452 in detail. The test script in Lib/test/test_scope.py demonstrates
2453 some of the effects of the change.
2454
2455 The new rules will cause existing code to break if it defines nested
2456 functions where an outer function has local variables with the same
2457 name as globals or builtins used by the inner function. Example:
2458
2459 def munge(str):
2460 def helper(x):
2461 return str(x)
2462 if type(str) != type(''):
2463 str = helper(str)
2464 return str.strip()
2465
2466 Under the old rules, the name str in helper() is bound to the
2467 builtin function str(). Under the new rules, it will be bound to
2468 the argument named str and an error will occur when helper() is
2469 called.
2470
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002471- The compiler will report a SyntaxError if "from ... import *" occurs
2472 in a function or class scope. The language reference has documented
2473 that this case is illegal, but the compiler never checked for it.
2474 The recent introduction of nested scope makes the meaning of this
2475 form of name binding ambiguous. In a future release, the compiler
2476 may allow this form when there is no possibility of ambiguity.
2477
Tim Peters40ead762001-01-27 05:35:26 +00002478- repr(string) is easier to read, now using hex escapes instead of octal,
2479 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2480
2481 >>> "\texample \r\n" + chr(0) + chr(255)
2482 '\texample \r\n\x00\xff' # in 2.1
2483 '\011example \015\012\000\377' # in 2.0
2484
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002485- Functions are now compared and hashed by identity, not by value, since
2486 the func_code attribute is writable.
2487
Fred Drakefb9d7122001-02-01 20:00:40 +00002488- Weak references (PEP 205) have been added. This involves a few
2489 changes in the core, an extension module (_weakref), and a Python
2490 module (weakref). The weakref module is the public interface. It
2491 includes support for "explicit" weak references, proxy objects, and
2492 mappings with weakly held values.
2493
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002494- A 'continue' statement can now appear in a try block within the body
2495 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002496 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002497
Tim Petersd7b5e882001-01-25 03:36:26 +00002498Standard library
2499
Barry Warsaw30dbd142001-01-31 22:14:01 +00002500- mailbox.py now has a new class, PortableUnixMailbox which is
2501 identical to UnixMailbox but uses a more portable scheme for
2502 determining From_ separators. Also, the constructors for all the
2503 classes in this module have a new optional `factory' argument, which
2504 is a callable used when new message classes must be instantiated by
2505 the next() method.
2506
Tim Petersd7b5e882001-01-25 03:36:26 +00002507- random.py is now self-contained, and offers all the functionality of
2508 the now-deprecated whrandom.py. See the docs for details. random.py
2509 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002510 and restoring the internal state of the generator; and jumpahead(n),
2511 for quickly forcing the internal state to be the same as if n calls to
2512 random() had been made. The latter is particularly useful for multi-
2513 threaded programs, creating one instance of the random.Random() class for
2514 each thread, then using .jumpahead() to force each instance to use a
2515 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002516
Tim Peters0de88fc2001-02-01 04:59:18 +00002517- random.py's seed() function is new. For bit-for-bit compatibility with
2518 prior releases, use the whseed function instead. The new seed function
2519 addresses two problems: (1) The old function couldn't produce more than
2520 about 2**24 distinct internal states; the new one about 2**45 (the best
2521 that can be done in the Wichmann-Hill generator). (2) The old function
2522 sometimes produced identical internal states when passed distinct
2523 integers, and there was no simple way to predict when that would happen;
2524 the new one guarantees to produce distinct internal states for all
2525 arguments in [0, 27814431486576L).
2526
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002527- The socket module now supports raw packets on Linux. The socket
2528 family is AF_PACKET.
2529
Tim Peters9ea17ac2001-02-02 05:57:15 +00002530- test_capi.py is a start at running tests of the Python C API. The tests
2531 are implemented by the new Modules/_testmodule.c.
2532
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002533- A new extension module, _symtable, provides provisional access to the
2534 internal symbol table used by the Python compiler. A higher-level
2535 interface will be added on top of _symtable in a future release.
2536
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002537- Removed the obsolete soundex module.
2538
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002539- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2540 the isSameNode method; NamedNodeMap the get method.
2541
2542- xml.sax.expatreader supports the lexical handler property; it
2543 generates comment, startCDATA, and endCDATA events.
2544
Tim Petersee826f82001-01-31 19:39:44 +00002545Windows changes
2546
2547- Build procedure: the zlib project is built in a different way that
2548 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002549 the zlib binary used. See PCbuild\readme.txt for details. Your old
2550 zlib-related directories can be deleted; you'll need to download fresh
2551 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002552
Tim Peters9ea17ac2001-02-02 05:57:15 +00002553- Build: New subproject _test for the benefit of test_capi.py (see above).
2554
Tim Petersb16c56f2001-02-02 21:24:51 +00002555- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2556 interface to some Python compiler internals).
2557
2558- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002559 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002560
Tim Petersa3a3a032000-11-30 05:22:44 +00002561What's New in Python 2.1 alpha 1?
2562=================================
2563
2564Core language, builtins, and interpreter
2565
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002566- There is a new Unicode companion to the PyObject_Str() API
2567 called PyObject_Unicode(). It behaves in the same way as the
2568 former, but assures that the returned value is an Unicode object
2569 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002570
Guido van Rossumf98eda02001-01-17 15:54:45 +00002571- The comparison operators support "rich comparison overloading" (PEP
2572 207). C extension types can provide a rich comparison function in
2573 the new tp_richcompare slot in the type object. The cmp() function
2574 and the C function PyObject_Compare() first try the new rich
2575 comparison operators before trying the old 3-way comparison. There
2576 is also a new C API PyObject_RichCompare() (which also falls back on
2577 the old 3-way comparison, but does not constrain the outcome of the
2578 rich comparison to a Boolean result).
2579
2580 The rich comparison function takes two objects (at least one of
2581 which is guaranteed to have the type that provided the function) and
2582 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2583 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2584 object, which may be NotImplemented (in which case the tp_compare
2585 slot function is used as a fallback, if defined).
2586
2587 Classes can overload individual comparison operators by defining one
2588 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002589 __ge__. There are no explicit "reflected argument" versions of
2590 these; instead, __lt__ and __gt__ are each other's reflection,
2591 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2592 reflection (similar at the C level). No other implications are
2593 made; in particular, Python does not assume that == is the Boolean
2594 inverse of !=, or that < is the Boolean inverse of >=. This makes
2595 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002596
2597 Classes or types that want to implement (in)equality tests but not
2598 the ordering operators (i.e. unordered types) should implement ==
2599 and !=, and raise an error for the ordering operators.
2600
Guido van Rossuma88479f2001-01-18 14:28:08 +00002601 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002602 Boolean; e.g. a matrix type might want to return a matrix of bits
2603 for A < B, giving elementwise comparisons. Such types should ensure
2604 that any interpretation of their value in a Boolean context raises
2605 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2606 at the C level) to always raise an exception.
2607
Guido van Rossuma88479f2001-01-18 14:28:08 +00002608- Complex numbers use rich comparisons to define == and != but raise
2609 an exception for <, <=, > and >=. Unfortunately, this also means
2610 that cmp() of two complex numbers raises an exception when the two
2611 numbers differ. Since it is not mathematically meaningful to compare
2612 complex numbers except for equality, I hope that this doesn't break
2613 too much code.
2614
Tim Peters3389f192001-02-18 08:48:49 +00002615- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002616 not defined by the language, other than that it's arbitrary but
2617 consistent (see the Reference Manual). An implementation detail changed
2618 in 2.1a1 such that None now compares less than any other object. Code
2619 relying on this new behavior (like code that relied on the previous
2620 behavior) does so at its own risk.
2621
Barry Warsaw573b5412001-01-15 20:43:18 +00002622- Functions and methods now support getting and setting arbitrarily
2623 named attributes (PEP 232). Functions have a new __dict__
2624 (a.k.a. func_dict) which hold the function attributes. Methods get
2625 and set attributes on their underlying im_func. It is a TypeError
2626 to set an attribute on a bound method.
2627
Guido van Rossum051e3352001-01-15 19:11:10 +00002628- The xrange() object implementation has been improved so that
2629 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2630 limitation that in this case len(xrange(sys.maxint)) can't be
2631 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2632 work fine as long as the index i doesn't actually reach 2**31.
2633 (Python uses regular ints for sequence and string indices; fixing
2634 that is much more work.)
2635
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002636- Two changes to from...import:
2637
Guido van Rossumba381232001-02-03 15:06:40 +00002638 1) "from M import X" now works even if (after loading module M)
2639 sys.modules['M'] is not a real module; it's basically a getattr()
2640 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002641
2642 2) "from M import *" now looks for M.__all__ to decide which names to
2643 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2644 filters out names starting with '_' as before. Whether or not
2645 __all__ exists, there's no restriction on the type of M.
2646
Guido van Rossumf61f1662001-01-10 20:13:55 +00002647- File objects have a new method, xreadlines(). This is the fastest
2648 way to iterate over all lines in a file:
2649
2650 for line in file.xreadlines():
2651 ...do something to line...
2652
2653 See the xreadlines module (mentioned below) for how to do this for
2654 other file-like objects.
2655
2656- Even if you don't use file.xreadlines(), you may expect a speedup on
2657 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002658 quite a bit in platform-specific ways: on systems (like Linux) that
2659 support flockfile(), getc_unlocked(), and funlockfile(), those are
2660 used by default. On systems (like Windows) without getc_unlocked(),
2661 a complicated (but still thread-safe) method using fgets() is used by
2662 default.
2663
Tim Petersd52269b2001-01-25 06:23:18 +00002664 You can force use of the fgets() method by #define'ing
2665 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002666 getc_unlocked()).
2667
Tim Petersd52269b2001-01-25 06:23:18 +00002668 You can force fgets() not to be used by #define'ing
2669 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002670 test_bufio.py fails -- and let us know if it does!).
2671
2672- In addition, the fileinput module, while still slower than the other
2673 methods on most platforms, has been sped up too, by using
2674 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002675
2676- Support for run-time warnings has been added, including a new
2677 command line option (-W) to specify the disposition of warnings.
2678 See the description of the warnings module below.
2679
2680- Extensive changes have been made to the coercion code. This mostly
2681 affects extension modules (which can now implement mixed-type
2682 numerical operators without having to use coercion), but
2683 occasionally, in boundary cases the coercion semantics have changed
2684 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002685 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002686 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002687 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002688
Guido van Rossumf98eda02001-01-17 15:54:45 +00002689- In connection with the coercion changes, a new built-in singleton
2690 object, NotImplemented is defined. This can be returned for
2691 operations that wish to indicate they are not implemented for a
2692 particular combination of arguments. From C, this is
2693 Py_NotImplemented.
2694
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002695- The interpreter accepts now bytecode files on the command line even
2696 if they do not have a .pyc or .pyo extension. On Linux, after executing
2697
Martin v. Löwise214baa2001-02-04 22:37:56 +00002698import imp,sys,string
2699magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2700reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2701open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002702
2703 any byte code file can be used as an executable (i.e. as an argument
2704 to execve(2)).
2705
Tim Peters9940b802000-12-01 07:59:35 +00002706- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002707 character. In 1.6 and earlier, they never produced a sign,
2708 and raised an error if the value of the long was too large
2709 to fit in a Python int. In 2.0, they produced a sign if and
2710 only if too large to fit in an int. This was inconsistent
2711 across platforms (because the size of an int varies across
2712 platforms), and inconsistent with hex() and oct(). Example:
2713
2714 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002715 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002716 'ffffffbe' # in 2.0 and before, on 32-bit machines
2717 >>> hex(-0x42L)
2718 '-0x42L' # in all versions of Python
2719
Tim Peters9940b802000-12-01 07:59:35 +00002720 The behavior of %d formats for negative Python longs remains
2721 the same as in 2.0 (although in 1.6 and before, they raised
2722 an error if the long didn't fit in a Python int).
2723
2724 %u formats don't make sense for Python longs, but are allowed
2725 and treated the same as %d in 2.1. In 2.0, a negative long
2726 formatted via %u produced a sign if and only if too large to
2727 fit in an int. In 1.6 and earlier, a negative long formatted
2728 via %u raised an error if it was too big to fit in an int.
2729
Guido van Rossum3661d392000-12-12 22:10:31 +00002730- Dictionary objects have an odd new method, popitem(). This removes
2731 an arbitrary item from the dictionary and returns it (in the form of
2732 a (key, value) pair). This can be useful for algorithms that use a
2733 dictionary as a bag of "to do" items and repeatedly need to pick one
2734 item. Such algorithms normally end up running in quadratic time;
2735 using popitem() they can usually be made to run in linear time.
2736
Tim Peters36cdad12000-12-29 02:06:45 +00002737Standard library
2738
Thomas Woutersfe385252001-01-19 23:16:56 +00002739- In the time module, the time argument to the functions strftime,
2740 localtime, gmtime, asctime and ctime is now optional, defaulting to
2741 the current time (in the local timezone).
2742
Guido van Rossumda91f222001-01-15 16:36:08 +00002743- The ftplib module now defaults to passive mode, which is deemed a
2744 more useful default given that clients are often inside firewalls
2745 these days. Note that this could break if ftplib is used to connect
2746 to a *server* that is inside a firewall, from outside; this is
2747 expected to be a very rare situation. To fix that, you can call
2748 ftp.set_pasv(0).
2749
Martin v. Löwis10a27872001-01-13 09:54:41 +00002750- The module site now treats .pth files not only for path configuration,
2751 but also supports extensions to the initialization code: Lines starting
2752 with import are executed.
2753
Guido van Rossumf61f1662001-01-10 20:13:55 +00002754- There's a new module, warnings, which implements a mechanism for
2755 issuing and filtering warnings. There are some new built-in
2756 exceptions that serve as warning categories, and a new command line
2757 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2758 turns warnings into errors). warnings.warn(message[, category])
2759 issues a warning message; this can also be called from C as
2760 PyErr_Warn(category, message).
2761
2762- A new module xreadlines was added. This exports a single factory
2763 function, xreadlines(). The intention is that this code is the
2764 absolutely fastest way to iterate over all lines in an open
2765 file(-like) object:
2766
2767 import xreadlines
2768 for line in xreadlines.xreadlines(file):
2769 ...do something to line...
2770
2771 This is equivalent to the previous the speed record holder using
2772 file.readlines(sizehint). Note that if file is a real file object
2773 (as opposed to a file-like object), this is equivalent:
2774
2775 for line in file.xreadlines():
2776 ...do something to line...
2777
Tim Peters36cdad12000-12-29 02:06:45 +00002778- The bisect module has new functions bisect_left, insort_left,
2779 bisect_right and insort_right. The old names bisect and insort
2780 are now aliases for bisect_right and insort_right. XXX_right
2781 and XXX_left methods differ in what happens when the new element
2782 compares equal to one or more elements already in the list: the
2783 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002784 right. Code that doesn't care where equal elements end up should
2785 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002786
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002787- The new curses.panel module wraps the panel library that forms part
2788 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2789
Guido van Rossumf61f1662001-01-10 20:13:55 +00002790- The SocketServer module now sets the allow_reuse_address flag by
2791 default in the TCPServer class.
2792
2793- A new function, sys._getframe(), returns the stack frame pointer of
2794 the caller. This is intended only as a building block for
2795 higher-level mechanisms such as string interpolation.
2796
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002797- The pyexpat module supports a number of new handlers, which are
2798 available only in expat 1.2. If invocation of a callback fails, it
2799 will report an additional frame in the traceback. Parser objects
2800 participate now in garbage collection. If expat reports an unknown
2801 encoding, pyexpat will try to use a Python codec; that works only
2802 for single-byte charsets. The parser type objects is exposed as
2803 XMLParserObject.
2804
2805- xml.dom now offers standard definitions for symbolic node type and
2806 exception code constants, and a hierarchy of DOM exceptions. minidom
2807 was adjusted to use them.
2808
2809- The conformance of xml.dom.minidom to the DOM specification was
2810 improved. It detects a number of additional error cases; the
2811 previous/next relationship works even when the tree is modified;
2812 Node supports the normalize() method; NamedNodeMap, DocumentType and
2813 DOMImplementation classes were added; Element supports the
2814 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2815 method.
2816
Guido van Rossumf61f1662001-01-10 20:13:55 +00002817Build issues
2818
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002819- For Unix (and Unix-compatible) builds, configuration and building of
2820 extension modules is now greatly automated. Rather than having to
2821 edit the Modules/Setup file to indicate which modules should be
2822 built and where their include files and libraries are, a
2823 distutils-based setup.py script now takes care of building most
2824 extension modules. All extension modules built this way are built
2825 as shared libraries. Only a few modules that must be linked
2826 statically are still listed in the Setup file; you won't need to
2827 edit their configuration.
2828
2829- Python should now build out of the box on Cygwin. If it doesn't,
2830 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002831
2832- Python now always uses its own (renamed) implementation of getopt()
2833 -- there's too much variation among C library getopt()
2834 implementations.
2835
2836- C++ compilers are better supported; the CXX macro is always set to a
2837 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002838
Tim Petersd92dfe02000-12-12 01:18:41 +00002839Windows changes
2840
2841- select module: By default under Windows, a select() call
2842 can specify no more than 64 sockets. Python now boosts
2843 this Microsoft default to 512. If you need even more than
2844 that, see the MS docs (you'll need to #define FD_SETSIZE
2845 and recompile Python from source).
2846
Guido van Rossumf61f1662001-01-10 20:13:55 +00002847- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2848 subdirectory is no more!
2849
Tim Petersa3a3a032000-11-30 05:22:44 +00002850
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002851What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002852=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002853
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002854Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002855changes are in the file HISTORY. If you are making the jump directly
2856from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2857HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002858
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002859Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2860the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2861http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002862
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002863--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002864
2865======================================================================
2866
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002867What's new in 2.0 (since release candidate 1)?
2868==============================================
2869
2870Standard library
2871
2872- The copy_reg module was modified to clarify its intended use: to
2873 register pickle support for extension types, not for classes.
2874 pickle() will raise a TypeError if it is passed a class.
2875
2876- Fixed a bug in gettext's "normalize and expand" code that prevented
2877 it from finding an existing .mo file.
2878
2879- Restored support for HTTP/0.9 servers in httplib.
2880
Tim Peters989b7b92000-10-16 20:24:53 +00002881- The math module was changed to stop raising OverflowError in case of
2882 underflow, and return 0 instead in underflow cases. Whether Python
2883 used to raise OverflowError in case of underflow was platform-
2884 dependent (it did when the platform math library set errno to ERANGE
2885 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002886
2887- Fixed a bug in StringIO that occurred when the file position was not
2888 at the end of the file and write() was called with enough data to
2889 extend past the end of the file.
2890
2891- Fixed a bug that caused Tkinter error messages to get lost on
2892 Windows. The bug was fixed by replacing direct use of
2893 interp->result with Tcl_GetStringResult(interp).
2894
2895- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2896 redirect response.
2897
2898- Several changes were made to distutils: Some debugging code was
2899 removed from util. Fixed the installer used when an external zip
2900 program (like WinZip) is not found; the source code for this
2901 installer is in Misc/distutils. check_lib() was modified to behave
2902 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2903 test for whether installed modules are on sys.path was changed to
2904 use both normcase() and normpath().
2905
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002906- Several minor bugs were fixed in the xml package (the minidom,
2907 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002908
2909- The regression test driver (regrtest.py) behavior when invoked with
2910 -l changed: It now reports a count of objects that are recognized as
2911 garbage but not freed by the garbage collector.
2912
Tim Peters989b7b92000-10-16 20:24:53 +00002913- The regression test for the math module was changed to test
2914 exceptional behavior when the test is run in verbose mode. Python
2915 cannot yet guarantee consistent exception behavior across platforms,
2916 so the exception part of test_math is run only in verbose mode, and
2917 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002918
2919Internals
2920
2921- PyOS_CheckStack() has been disabled on Win64, where it caused
2922 test_sre to fail.
2923
2924Build issues
2925
2926- Changed compiler flags, so that gcc is always invoked with -Wall and
2927 -Wstrict-prototypes. Users compiling Python with GCC should see
2928 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002929 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002930 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002931
Tim Petersa3a3a032000-11-30 05:22:44 +00002932- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002933
2934Tools and other miscellany
2935
2936- The compiler in Tools/compiler was updated to support the new
2937 language features introduced in 2.0: extended print statement, list
2938 comprehensions, and augmented assignments. The new compiler should
2939 also be backwards compatible with Python 1.5.2; the compiler will
2940 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002941 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002942
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002943What's new in 2.0 release candidate 1 (since beta 2)?
2944=====================================================
2945
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002946What is release candidate 1?
2947
2948We believe that release candidate 1 will fix all known bugs that we
2949intend to fix for the 2.0 final release. This release should be a bit
2950more stable than the previous betas. We would like to see even more
2951widespread testing before the final release, so we are producing this
2952release candidate. The final release will be exactly the same unless
2953any show-stopping (or brown bag) bugs are found by testers of the
2954release candidate.
2955
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002956All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002957to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002958
2959Core language, builtins, and interpreter
2960
2961- A bug that caused crashes when __coerce__ was used with augmented
2962 assignment, e.g. +=, was fixed.
2963
2964- Raise ZeroDivisionError when raising zero to a negative number,
2965 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2966 power operator and the result of math.pow(0.0, -2.0) will vary by
2967 platform. On Linux, it raises a ValueError.
2968
2969- A bug in Unicode string interpolation was fixed that occasionally
2970 caused errors with formats including "%%". For example, the
2971 following expression "%% %s" % u"abc" no longer raises a TypeError.
2972
2973- Compilation of deeply nested expressions raises MemoryError instead
2974 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2975
2976- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2977 rendering them useless. They are now written in binary mode again.
2978
2979Standard library
2980
2981- Keyword arguments are now accepted for most pattern and match object
2982 methods in SRE, the standard regular expression engine.
2983
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002984- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002985 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002986
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002987- Several bugs in the Unicode handling and error handling in _tkinter
2988 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002989
2990- Fix memory management errors in Merge() and Tkapp_Call() routines.
2991
2992- Several changes were made to cStringIO to make it compatible with
2993 the file-like object interface and with StringIO. If operations are
2994 performed on a closed object, an exception is raised. The truncate
2995 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002996 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002997
2998- There were many changes made to the linuxaudiodev module and its
2999 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00003000 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003001
3002 Note that this module is named poorly, because it should work
3003 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00003004 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003005
3006 The module now raises exceptions when errors occur instead of
3007 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
3008 audio) and defines a getptr() method that calls the
3009 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
3010
3011- The library_version attribute, introduced in an earlier beta, was
3012 removed because it can not be supported with early versions of the C
3013 readline library, which provides no way to determine the version at
3014 compile-time.
3015
3016- The binascii module is now enabled on Win64.
3017
Tim Peters46446d62000-10-09 21:19:31 +00003018- tokenize.py no longer suffers "recursion depth" errors when parsing
3019 programs with very long string literals.
3020
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003021Internals
3022
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003023- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003024 which is called when the interpreter starts up to determine where
3025 the standard library is installed. These vulnerabilities affect all
3026 previous versions of Python and can be exploited by setting very
3027 long values for PYTHONHOME or argv[0]. The risk is greatest for a
3028 setuid Python script, although use of the wrapper in
3029 Misc/setuid-prog.c will eliminate the vulnerability.
3030
3031- Fixed garbage collection bugs in instance creation that were
3032 triggered when errors occurred during initialization. The solution,
3033 applied in cPickle and in PyInstance_New(), is to call
3034 PyObject_GC_Init() after the initialization of the object's
3035 container attributes is complete.
3036
3037- pyexpat adds definitions of PyModule_AddStringConstant and
3038 PyModule_AddObject if the Python version is less than 2.0, which
3039 provides compatibility with PyXML on Python 1.5.2.
3040
3041- If the platform has a bogus definition for LONG_BIT (the number of
3042 bits in a long), an error will be reported at compile time.
3043
3044- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
3045 collection crashes and possibly other, unreported crashes.
3046
3047- Fixed a memory leak in _PyUnicode_Fini().
3048
3049Build issues
3050
3051- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003052 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00003053 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003054
3055- The mmap.PAGESIZE constant is now initialized using sysconf when
3056 possible, which eliminates a dependency on -lucb for Reliant UNIX.
3057
3058- The md5 file should now compile on all platforms.
3059
3060- The select module now compiles on platforms that do not define
3061 POLLRDNORM and related constants.
3062
3063- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00003064 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003065
Jeremy Hylton10921202000-10-09 18:34:12 +00003066- BeOS: A number of changes were made to the build and installation
3067 process. ar-fake now operates on a directory of object files.
3068 dl_export.h is gone, and its macros now appear on the mwcc command
3069 line during build on PPC BeOS.
3070
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003071- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00003072 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003073
3074- Cygwin: Support for shared libraries, Tkinter, and sockets.
3075
3076- SunOS 4.1.4_JL: Fix test for directory existence in configure.
3077
3078Tools and other miscellany
3079
3080- Removed debugging prints from main used with freeze.
3081
Tim Peters46446d62000-10-09 21:19:31 +00003082- IDLE auto-indent no longer crashes when it encounters Unicode
3083 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003084
3085What's new in 2.0 beta 2 (since beta 1)?
3086========================================
3087
3088Core language, builtins, and interpreter
3089
Tim Peters482c0212000-09-26 06:33:09 +00003090- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003091 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003092
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003093- Add -h and -V command line options to print the usage message and
3094 Python version number and exit immediately.
3095
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003096- eval() and exec accept Unicode objects as code parameters.
3097
3098- getattr() and setattr() now also accept Unicode objects for the
3099 attribute name, which are converted to strings using the default
3100 encoding before lookup.
3101
3102- Multiplication on string and Unicode now does proper bounds
3103 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
3104 string is too long."
3105
3106- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00003107 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003108
Jeremy Hylton1b618592000-09-26 05:32:36 +00003109
3110Standard library and extensions
3111
Guido van Rossum5b08f132001-04-16 02:05:23 +00003112- socket module: the OpenSSL code now adds support for RAND_status()
3113 and EGD (Entropy Gathering Device).
3114
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003115- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00003116 argument checking; it still takes no arguments.
3117
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003118- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003119
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003120- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003121
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003122- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003123
3124- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003125 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003126
3127- copy: Copy Unicode objects atomically.
3128
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003129- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003130
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003131- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003132
Fred Drake67233bc2000-09-26 16:40:27 +00003133- dbm: Add get() and setdefault() methods to dbm object. Add constant
3134 `library' to module that names the library used. Added doc strings
3135 and method names to error messages. Uses configure to determine
3136 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
3137 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003138
3139- distutils: Update to version 0.9.3.
3140
3141- dl: Add several dl.RTLD_ constants.
3142
3143- fpectl: Now supported on FreeBSD.
3144
3145- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
3146 found by the collector will be saved in gc.garbage. This is useful
3147 for debugging a program that creates reference cycles.
3148
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003149- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00003150 of HTTP class. Do not close socket on zero-length response. Do not
3151 crash when server sends invalid content-length header.
3152
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003153- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003154
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003155- marshal: When reading a short, sign-extend on platforms where shorts
3156 are bigger than 16 bits. When reading a long, repair the unportable
3157 sign extension that was being done for 64-bit machines. (It assumed
3158 that signed right shift sign-extends.)
3159
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003160- operator: Add contains(), invert(), __invert__() as aliases for
3161 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003162
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003163- os: Add support for popen2() and popen3() on all platforms where
3164 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003165
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003166- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00003167 clicking on a file in Explorer (or passing the file name to the
3168 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003169
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003170- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00003171 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003172
3173- pickle: Now raises ValueError when an invalid pickle that contains
3174 a non-string repr where a string repr was expected. This behavior
3175 matches cPickle.
3176
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003177- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003178
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003179- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003180
3181- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003182 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003183 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003184
3185- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003186 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003187
3188- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00003189 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00003190 few cycles during startup since the first call to
3191 setdefaultencoding() will initialize the codec registry and the
3192 encodings package.
3193
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003194- socket: Support for size hint in readlines() method of object returned
3195 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003196
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003197- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00003198 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00003199 is followed by whitespace.
3200
Tim Petersa3a3a032000-11-30 05:22:44 +00003201- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003202
3203- struct: Check ranges for bytes and shorts.
3204
3205- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003206 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003207
3208- Tkinter: Image objects are now guaranteed to have unique ids. Set
3209 event.delta to zero if Tk version doesn't support mousewheel.
3210 Removed some debugging prints.
3211
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003212- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003213
Fred Drake67233bc2000-09-26 16:40:27 +00003214- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003215 which works around a bug in Norton AntiVirus 2000 that leads directly
3216 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003217
3218- xml: New version detection code allows PyXML to override standard
3219 XML package if PyXML version is greater than 0.6.1.
3220
Fred Drake64bb3802000-09-26 16:21:35 +00003221- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
3222 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
3223 tree only for nodes which are sufficiently interesting to a specific
3224 application. Does not provide the HTML-specific extensions. Still
3225 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003226
Fred Drake64bb3802000-09-26 16:21:35 +00003227- xml.sax: SAX 2 support for Python, including all the handler
3228 interfaces needed to process XML 1.0 compliant XML. Some
3229 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003230
Fred Drake64bb3802000-09-26 16:21:35 +00003231- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
3232 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003233
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003234
Jeremy Hylton1b618592000-09-26 05:32:36 +00003235C API
3236
3237- Add three new convenience functions for module initialization --
3238 PyModule_AddObject(), PyModule_AddIntConstant(), and
3239 PyModule_AddStringConstant().
3240
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003241- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00003242 removed and add #error to Python.h if NULL isn't defined after
3243 #include of stdio.h.
3244
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003245- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00003246 backwards compatibility (at the source level) with old extensions.
3247
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003248- A wrapper API was added for signal() and sigaction(). Instead of
3249 either function, always use PyOS_getsig() to get a signal handler
3250 and PyOS_setsig() to set one. A new convenience typedef
3251 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003252
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003253- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00003254 internal data buffer and size of a string object -- or the default
3255 encoded version of a Unicode object.
3256
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003257- PyString_Size() and PyString_AsString() accept Unicode objects.
3258
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003259- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00003260 exists). INT_MAX and LONG_MAX will always be defined, even if
3261 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003262
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003263- PyFloat_FromString takes a second argument, pend, that was
3264 effectively useless. It is now officially useless but preserved for
3265 backwards compatibility. If the pend argument is not NULL, *pend is
3266 set to NULL.
3267
3268- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
3269 for the attribute name. See note on getattr() above.
3270
3271- A few bug fixes to argument processing for Unicode.
3272 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
3273 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
3274 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00003275 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003276
3277- Py_BuildValue accepts B format (for bgen-generated code).
3278
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003279
Jeremy Hylton1b618592000-09-26 05:32:36 +00003280Internals
3281
3282- On Unix, fix code for finding Python installation directory so that
3283 it works when argv[0] is a relative path.
3284
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00003285- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003286 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00003287 rather than by generating a copy of the object.
3288
Tim Peters482c0212000-09-26 06:33:09 +00003289- Several of the internal Unicode tables are much smaller now, and
3290 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003291
Jeremy Hylton97693b02000-09-26 17:42:51 +00003292- In the garbage collector: Fixed bug in collection of tuples. Fixed
3293 bug that caused some instances to be removed from the container set
3294 while they were still live. Fixed parsing in gc.set_debug() for
3295 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003296
3297- Fixed refcount problem in instance deallocation that only occurred
3298 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
3299
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003300- On Windows, getpythonregpath is now protected against null data in
3301 registry key.
3302
3303- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00003304 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003305
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003306
Jeremy Hylton1b618592000-09-26 05:32:36 +00003307Build and platform-specific issues
3308
3309- Better support of GNU Pth via --with-pth configure option.
3310
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003311- Python/C API now properly exposed to dynamically-loaded extension
3312 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003313
3314- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
3315 Don't define MS_SYNC to be zero when it is undefined. Added missing
3316 prototypes in posixmodule.c.
3317
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003318- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003319 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003320
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003321- Fix largefile support on older NetBSD systems and OpenBSD by adding
3322 define for TELL64.
3323
3324
3325Tools and other miscellany
3326
3327- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
3328
3329- freeze: The modulefinder now works with 2.0 opcodes.
3330
Tim Petersa3a3a032000-11-30 05:22:44 +00003331- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003332 Move hackery of sys.argv until after the Tk instance has been
3333 created, which allows the application-specific Tkinter
3334 initialization to be executed if present; also pass an explicit
3335 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00003336
Jeremy Hylton1b618592000-09-26 05:32:36 +00003337
3338What's new in 2.0 beta 1?
3339=========================
3340
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003341Source Incompatibilities
3342------------------------
3343
3344None. Note that 1.6 introduced several incompatibilities with 1.5.2,
3345such as single-argument append(), connect() and bind(), and changes to
3346str(long) and repr(float).
3347
3348
3349Binary Incompatibilities
3350------------------------
3351
3352- Third party extensions built for Python 1.5.x or 1.6 cannot be used
3353with Python 2.0; these extensions will have to be rebuilt for Python
33542.0.
3355
3356- On Windows, attempting to import a third party extension built for
3357Python 1.5.x or 1.6 results in an immediate crash; there's not much we
3358can do about this. Check your PYTHONPATH environment variable!
3359
3360- Python bytecode files (*.pyc and *.pyo) are not compatible between
3361releases.
3362
3363
3364Overview of Changes Since 1.6
3365-----------------------------
3366
3367There are many new modules (including brand new XML support through
3368the xml package, and i18n support through the gettext module); a list
3369of all new modules is included below. Lots of bugs have been fixed.
3370
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003371The process for making major new changes to the language has changed
3372since Python 1.6. Enhancements must now be documented by a Python
3373Enhancement Proposal (PEP) before they can be accepted.
3374
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003375There are several important syntax enhancements, described in more
3376detail below:
3377
3378 - Augmented assignment, e.g. x += 1
3379
3380 - List comprehensions, e.g. [x**2 for x in range(10)]
3381
3382 - Extended import statement, e.g. import Module as Name
3383
3384 - Extended print statement, e.g. print >> file, "Hello"
3385
3386Other important changes:
3387
3388 - Optional collection of cyclical garbage
3389
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003390Python Enhancement Proposal (PEP)
3391---------------------------------
3392
3393PEP stands for Python Enhancement Proposal. A PEP is a design
3394document providing information to the Python community, or describing
3395a new feature for Python. The PEP should provide a concise technical
3396specification of the feature and a rationale for the feature.
3397
3398We intend PEPs to be the primary mechanisms for proposing new
3399features, for collecting community input on an issue, and for
3400documenting the design decisions that have gone into Python. The PEP
3401author is responsible for building consensus within the community and
3402documenting dissenting opinions.
3403
3404The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003405
3406Augmented Assignment
3407--------------------
3408
3409This must have been the most-requested feature of the past years!
3410Eleven new assignment operators were added:
3411
Guido van Rossume905e952000-09-05 12:42:46 +00003412 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003413
3414For example,
3415
3416 A += B
3417
3418is similar to
3419
3420 A = A + B
3421
3422except that A is evaluated only once (relevant when A is something
3423like dict[index].attr).
3424
3425However, if A is a mutable object, A may be modified in place. Thus,
3426if A is a number or a string, A += B has the same effect as A = A+B
3427(except A is only evaluated once); but if a is a list, A += B has the
3428same effect as A.extend(B)!
3429
3430Classes and built-in object types can override the new operators in
3431order to implement the in-place behavior; the not-in-place behavior is
3432used automatically as a fallback when an object doesn't implement the
3433in-place behavior. For classes, the method name is derived from the
3434method name for the corresponding not-in-place operator by inserting
3435an 'i' in front of the name, e.g. __iadd__ implements in-place
3436__add__.
3437
3438Augmented assignment was implemented by Thomas Wouters.
3439
3440
3441List Comprehensions
3442-------------------
3443
3444This is a flexible new notation for lists whose elements are computed
3445from another list (or lists). The simplest form is:
3446
3447 [<expression> for <variable> in <sequence>]
3448
Guido van Rossum56db0952000-09-06 23:34:25 +00003449For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003450This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003451
3452You can also add a condition:
3453
3454 [<expression> for <variable> in <sequence> if <condition>]
3455
3456For example, [w for w in words if w == w.lower()] would yield the list
3457of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003458than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003459
3460You can also have nested for loops and more than one 'if' clause. For
3461example, here's a function that flattens a sequence of sequences::
3462
3463 def flatten(seq):
3464 return [x for subseq in seq for x in subseq]
3465
3466 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3467
3468This prints
3469
3470 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3471
3472List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003473Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003474
3475
3476Extended Import Statement
3477-------------------------
3478
3479Many people have asked for a way to import a module under a different
3480name. This can be accomplished like this:
3481
3482 import foo
3483 bar = foo
3484 del foo
3485
3486but this common idiom gets old quickly. A simple extension of the
3487import statement now allows this to be written as follows:
3488
3489 import foo as bar
3490
3491There's also a variant for 'from ... import':
3492
3493 from foo import bar as spam
3494
3495This also works with packages; e.g. you can write this:
3496
3497 import test.regrtest as regrtest
3498
3499Note that 'as' is not a new keyword -- it is recognized only in this
3500context (this is only possible because the syntax for the import
3501statement doesn't involve expressions).
3502
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003503Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003504
3505
3506Extended Print Statement
3507------------------------
3508
3509Easily the most controversial new feature, this extension to the print
3510statement adds an option to make the output go to a different file
3511than the default sys.stdout.
3512
3513For example, to write an error message to sys.stderr, you can now
3514write:
3515
3516 print >> sys.stderr, "Error: bad dog!"
3517
3518As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003519evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003520
3521 print >> None, "Hello world"
3522
3523is equivalent to
3524
3525 print "Hello world"
3526
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003527Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003528
3529
3530Optional Collection of Cyclical Garbage
3531---------------------------------------
3532
3533Python is now equipped with a garbage collector that can hunt down
3534cyclical references between Python objects. It's no replacement for
3535reference counting; in fact, it depends on the reference counts being
3536correct, and decides that a set of objects belong to a cycle if all
3537their reference counts can be accounted for from their references to
3538each other. This devious scheme was first proposed by Eric Tiedemann,
3539and brought to implementation by Neil Schemenauer.
3540
3541There's a module "gc" that lets you control some parameters of the
3542garbage collection. There's also an option to the configure script
3543that lets you enable or disable the garbage collection. In 2.0b1,
3544it's on by default, so that we (hopefully) can collect decent user
3545experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003546performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003547off by default in the final 2.0 release.
3548
3549
3550Smaller Changes
3551---------------
3552
3553A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3554map(None, seq1, seq2, ...) when the sequences have the same length;
3555i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3556the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003557zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003558
3559sys.version_info is a tuple (major, minor, micro, level, serial).
3560
3561Dictionaries have an odd new method, setdefault(key, default).
3562dict.setdefault(key, default) returns dict[key] if it exists; if not,
3563it sets dict[key] to default and returns that value. Thus:
3564
3565 dict.setdefault(key, []).append(item)
3566
3567does the same work as this common idiom:
3568
3569 if not dict.has_key(key):
3570 dict[key] = []
3571 dict[key].append(item)
3572
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003573There are two new variants of SyntaxError that are raised for
3574indentation-related errors: IndentationError and TabError.
3575
3576Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3577escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003578
3579The limits on the size of expressions and file in Python source code
3580have been raised from 2**16 to 2**32. Previous versions of Python
3581were limited because the maximum argument size the Python VM accepted
3582was 2**16. This limited the size of object constructor expressions,
3583e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3584limit was raised thanks to a patch by Charles Waldman that effectively
3585fixes the problem. It is now much more likely that you will be
3586limited by available memory than by an arbitrary limit in Python.
3587
3588The interpreter's maximum recursion depth can be modified by Python
3589programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3590limit is the maximum number of recursive calls that can be made by
3591Python code. The limit exists to prevent infinite recursion from
3592overflowing the C stack and causing a core dump. The default value is
35931000. The maximum safe value for a particular platform can be found
3594by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003595
3596New Modules and Packages
3597------------------------
3598
3599atexit - for registering functions to be called when Python exits.
3600
3601imputil - Greg Stein's alternative API for writing custom import
3602hooks.
3603
3604pyexpat - an interface to the Expat XML parser, contributed by Paul
3605Prescod.
3606
3607xml - a new package with XML support code organized (so far) in three
3608subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3609would fill a volume. There's a special feature whereby a
3610user-installed package named _xmlplus overrides the standard
3611xmlpackage; this is intended to give the XML SIG a hook to distribute
3612backwards-compatible updates to the standard xml package.
3613
3614webbrowser - a platform-independent API to launch a web browser.
3615
3616
Guido van Rossume905e952000-09-05 12:42:46 +00003617Changed Modules
3618---------------
3619
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003620array -- new methods for array objects: count, extend, index, pop, and
3621remove
3622
3623binascii -- new functions b2a_hex and a2b_hex that convert between
3624binary data and its hex representation
3625
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003626calendar -- Many new functions that support features including control
3627over which day of the week is the first day, returning strings instead
3628of printing them. Also new symbolic constants for days of week,
3629e.g. MONDAY, ..., SUNDAY.
3630
3631cgi -- FieldStorage objects have a getvalue method that works like a
3632dictionary's get method and returns the value attribute of the object.
3633
3634ConfigParser -- The parser object has new methods has_option,
3635remove_section, remove_option, set, and write. They allow the module
3636to be used for writing config files as well as reading them.
3637
3638ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003639optionally support the RFC 959 REST command.
3640
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003641gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003642
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003643httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3644the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003645
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003646locale -- implement getdefaultlocale for Win32 and Macintosh
3647
3648marshal -- no longer dumps core when marshaling deeply nested or
3649recursive data structures
3650
3651os -- new functions isatty, seteuid, setegid, setreuid, setregid
3652
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003653os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3654support under Unix.
3655
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003656os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003657
3658os.path -- fix semantics of os.path.commonprefix
3659
3660smtplib -- support for sending very long messages
3661
3662socket -- new function getfqdn()
3663
3664readline -- new functions to read, write and truncate history files.
3665The readline section of the library reference manual contains an
3666example.
3667
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003668select -- add interface to poll system call
3669
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003670shutil -- new copyfileobj function
3671
3672SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3673HTTP server.
3674
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003675Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003676
3677urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003678e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003679
3680whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003681
3682
3683Obsolete Modules
3684----------------
3685
3686None. However note that 1.6 made a whole slew of modules obsolete:
3687stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3688poly, zmod, strop, util, whatsound.
3689
3690
3691Changed, New, Obsolete Tools
3692----------------------------
3693
Tim Peters8b092332000-09-05 20:15:25 +00003694None.
Guido van Rossume905e952000-09-05 12:42:46 +00003695
3696
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003697C-level Changes
3698---------------
3699
3700Several cleanup jobs were carried out throughout the source code.
3701
3702All C code was converted to ANSI C; we got rid of all uses of the
3703Py_PROTO() macro, which makes the header files a lot more readable.
3704
3705Most of the portability hacks were moved to a new header file,
3706pyport.h; several other new header files were added and some old
3707header files were removed, in an attempt to create a more rational set
3708of header files. (Few of these ever need to be included explicitly;
3709they are all included by Python.h.)
3710
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003711Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003712and Win64, especially for the new Intel Itanium processor. Mick also
3713added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003714
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003715The C APIs to return an object's size have been update to consistently
3716use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3717previous versions, the abstract interfaces used PyXXX_Length and the
3718concrete interfaces used PyXXX_Size. The old names,
3719e.g. PyObject_Length, are still available for backwards compatibility
3720at the API level, but are deprecated.
3721
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003722The PyOS_CheckStack function has been implemented on Windows by
3723Fredrik Lundh. It prevents Python from failing with a stack overflow
3724on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003725
3726The GC changes resulted in creation of two new slots on object,
3727tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003728the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003729
3730The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003731C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003732
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003733PyErr_Format has been updated to automatically calculate the size of
3734the buffer needed to hold the formatted result string. This change
3735prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003736
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003737New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003738
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003739PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3740that are the same as their non-Ex counterparts except they take an
3741extra flag argument that tells them to close the file when done.
3742
3743XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003744
Tim Peters8b092332000-09-05 20:15:25 +00003745
3746Windows Changes
3747---------------
3748
3749New popen2/popen3/peopen4 in os module (see Changed Modules above).
3750
3751os.popen is much more usable on Windows 95 and 98. See Microsoft
3752Knowledge Base article Q150956. The Win9x workaround described there
3753is implemented by the new w9xpopen.exe helper in the root of your
3754Python installation. Note that Python uses this internally; it is not
3755a standalone program.
3756
3757Administrator privileges are no longer required to install Python
3758on Windows NT or Windows 2000. If you have administrator privileges,
3759Python's registry info will be written under HKEY_LOCAL_MACHINE.
3760Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003761under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003762uses of Python, but will prevent some advanced uses from working
3763(for example, running a Python script as an NT service, or possibly
3764from CGI).
3765
3766[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3767installer; instead, it installs the needed Tcl/Tk files directly in the
3768Python directory. If you already have a Tcl/Tk installation, this
3769wastes some disk space (about 4 Megs) but avoids problems with
3770conflicting Tcl/Tk installations, and makes it much easier for Python
3771to ensure that Tcl/Tk can find all its files.
3772
3773[This was new in 1.6] The Windows installer now installs by default in
3774\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3775
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003776
3777Updates to the changes between 1.5.2 and 1.6
3778--------------------------------------------
3779
3780The 1.6 NEWS file can't be changed after the release is done, so here
3781is some late-breaking news:
3782
3783New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3784and changes to getlocale() and setlocale().
3785
3786The new module is now enabled per default.
3787
3788It is not true that the encodings codecs cannot be used for normal
3789strings: the string.encode() (which is also present on 8-bit strings
3790!) allows using them for 8-bit strings too, e.g. to convert files from
3791cp1252 (Windows) to latin-1 or vice-versa.
3792
3793Japanese codecs are available from Tamito KAJIYAMA:
3794http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3795
3796
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003797======================================================================