blob: 5abfb42ee3a840450df3efc6db667b7120a5f5b4 [file] [log] [blame]
Tim Petersaf8446f2001-12-21 21:36:50 +00001What's New in Python 2.3 alpha 1?
2XXX Release date: DD-MMM-2002 XXX
3=================================
4
5Type/class unification and new-style classes
6
Guido van Rossume3438782002-08-12 03:42:03 +00007- Assignment to __class__ is disallowed if either the old and the new
8 class is a statically allocated type object (such as defined by an
9 extenson module). This prevents anomalies like 2.__class__ = bool.
10
11- New-style object creation and deallocation have been sped up
12 significantly; they are now faster than classic instance creation
13 and deallocation.
14
15- The __slots__ variable can now mention "private" names, and the
16 right thing will happen (e.g. __slots__ = ["__foo"]).
17
18- The built-ins slice() and buffer() are now callable types. The
19 types classobj (formerly class), code, function, instance, and
20 instancemethod (formerly instance-method), which have no built-in
21 names but are accessible through the types module, are now also
22 callable. The type dict-proxy is renamed to dictproxy.
23
24- Cycles going through the __class__ link of a new-style instance are
25 now detected by the garbage collector.
26
27- Classes using __slots__ are now properly garbage collected.
28 [SF bug 519621]
29
30- Tightened the __slots__ rules: a slot name must be a valid Python
31 identifier.
32
33- The constructor for the module type now requires a name argument and
34 takes an optional docstring argument. Previously, this constructor
35 ignored its arguments. As a consequence, deriving a class from a
36 module (not from the module type) is now illegal; previously this
37 created an unnamed module, just like invoking the module type did.
38 [SF bug 563060]
39
40- A new type object, 'basestring', is added. This is a common base type
41 for 'str' and 'unicode', and can be used instead of
42 types.StringTypes, e.g. to test whether something is "a string":
43 isinstance(x, basestring) is True for Unicode and 8-bit strings. This
44 is an abstract base class and cannot be instantiated directly.
45
46- Changed new-style class instantiation so that when C's __new__
47 method returns something that's not a C instance, its __init__ is
48 not called. [SF bug #537450]
49
50- Fixed super() to work correctly with class methods. [SF bug #535444]
51
52- If you try to pickle an instance of a class that has __slots__ but
53 doesn't define or override __getstate__, a TypeError is now raised.
54 This is done by adding a bozo __getstate__ to the class that always
55 raises TypeError. (Before, this would appear to be pickled, but the
56 state of the slots would be lost.)
57
Tim Petersaf8446f2001-12-21 21:36:50 +000058Core and builtins
59
Guido van Rossum9be89462002-08-14 16:11:30 +000060- There's a new warning category, FutureWarning. This is used to warn
61 about a number of situations where the value or sign of an integer
62 result will change in Python 2.4 as a result of PEP 237 (integer
63 unification). The warnings implement stage B0 mentioned in that
64 PEP. The warnings are about the following situations:
65
66 - Octal and hex literals without 'L' prefix in the inclusive range
67 [0x80000000..0xffffffff]; these are currently negative ints, but
68 in Python 2.4 they will be positive longs with the same bit
69 pattern.
70
71 - Left shifts on integer values that cause the outcome to lose
72 bits or have a different sign than the left operand. To be
73 precise: x<<n where this currently doesn't yield the same value
74 as long(x)<<n; in Python 2.4, the outcome will be long(x)<<n.
75
76 - Conversions from ints to string that show negative values as
77 unsigned ints in the inclusive range [0x80000000..0xffffffff];
78 this affects the functions hex() and oct(), and the string
79 formatting codes %u, %o, %x, and %X. In Python 2.4, these will
80 show signed values (e.g. hex(-1) currently returns "0xffffffff";
81 in Python 2.4 it will return "-0x1").
82
Tim Petersd64c1de2002-08-12 17:36:03 +000083- When multiplying very large integers, a version of the so-called
84 Karatsuba algorithm is now used. This is most effective if the
85 inputs have roughly the same size. If they both have about N digits,
86 Karatsuba multiplication has O(N**1.58) runtime (the exponent is
87 log_base_2(3)) instead of the previous O(N**2). Measured results may
88 be better or worse than that, depending on platform quirks. Note that
89 this is a simple implementation, and there's no intent here to compete
Tim Peters60004642002-08-12 22:01:34 +000090 with, e.g., GMP. It gives a very nice speedup when it applies, but
91 a package devoted to fast large-integer arithmetic should run circles
92 around it.
Tim Peters5af4e6c2002-08-12 02:31:19 +000093
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +000094- u'%c' will now raise a ValueError in case the argument is an
95 integer outside the valid range of Unicode code point ordinals.
96
Guido van Rossumdeb09362002-08-09 17:16:30 +000097- The tempfile module has been overhauled for enhanced security. The
98 mktemp() function is now deprecated; new, safe replacements are
99 mkstemp() (for files) and mkdtemp() (for directories), and the
100 higher-level functions NamedTemporaryFile() and TemporaryFile().
101 Use of some global variables in this module is also deprecated; the
102 new functions have keyword arguments to provide the same
103 functionality. All Lib, Tools and Demo modules that used the unsafe
104 interfaces have been updated to use the safe replacements. Thanks
105 to Zack Weinberg!
106
Guido van Rossumd81a9832002-08-09 15:57:34 +0000107- When x is an object whose class implements __mul__ and __rmul__,
108 1.0*x would correctly invoke __rmul__, but 1*x would erroneously
109 invoke __mul__. This was due to the sequence-repeat code in the int
110 type. This has been fixed now.
111
Barry Warsawd79f6832002-08-06 17:01:51 +0000112- Previously, "str1 in str2" required str1 to be a string of length 1.
113 This restriction has been relaxed to allow str1 to be a string of
114 any length. Thus "'el' in 'hello world'" returns True now.
115
Guido van Rossumb57089c2002-08-06 16:20:26 +0000116- File objects are now their own iterators. For a file f, iter(f) now
117 returns f (unless f is closed), and f.next() is similar to
118 f.readline() when EOF is not reached; however, f.next() uses a
119 readahead buffer that messes up the file position, so mixing
120 f.next() and f.readline() (or other methods) doesn't work right.
121 Calling f.seek() drops the readahead buffer, but other operations
122 don't. It so happens that this gives a nice additional speed boost
123 to "for line in file:"; the xreadlines method and corresponding
Guido van Rossumbffb2ef2002-08-09 17:17:07 +0000124 module are now obsolete. Thanks to Oren Tirosh!
Guido van Rossumb57089c2002-08-06 16:20:26 +0000125
Guido van Rossumde392d32002-08-05 14:17:20 +0000126- Encoding declarations (PEP 263, phase 1) have been implemented. A
127 comment of the form "# -*- coding: <encodingname> -*-" in the first
128 or second line of a Python source file indicates the encoding.
Martin v. Löwis00f1e3f2002-08-04 17:29:52 +0000129
Tim Petersf47630f2002-08-01 02:34:51 +0000130- list.sort() has a new implementation. While cross-platform results
131 may vary, and in data-dependent ways, this is much faster on many
132 kinds of partially ordered lists than the previous implementation,
133 and reported to be just as fast on randomly ordered lists on
134 several major platforms. This sort is also stable (if A==B and A
135 precedes B in the list at the start, A precedes B after the sort too),
136 although the language definition does not guarantee stability. A
137 potential drawback is that list.sort() may require temp space of
138 len(list)*2 bytes (*4 on a 64-bit machine). It's therefore possible
139 for list.sort() to raise MemoryError now, even if a comparison function
140 does not. See <http://www.python.org/sf/587076> for full details.
141
Guido van Rossum2d5389c2002-07-23 03:44:35 +0000142- All standard iterators now ensure that, once StopIteration has been
143 raised, all future calls to next() on the same iterator will also
144 raise StopIteration. There used to be various counterexamples to
145 this behavior, which could caused confusion or subtle program
146 breakage, without any benefits. (Note that this is still an
147 iterator's responsibility; the iterator framework does not enforce
148 this.)
149
Mark Hammondc0e35152002-07-16 01:32:30 +0000150- Ctrl+C handling on Windows has been made more consistent with
151 other platforms. KeyboardInterrupt can now reliably be caught,
Tim Petersf47630f2002-08-01 02:34:51 +0000152 and Ctrl+C at an interative prompt no longer terminates the
Mark Hammondc0e35152002-07-16 01:32:30 +0000153 process under NT/2k/XP (it never did under Win9x). Ctrl+C will
Tim Peters5af4e6c2002-08-12 02:31:19 +0000154 interrupt time.sleep() in the main thread, and any child processes
155 created via the popen family (on win2k; we can't make win9x work
Mark Hammond8f3afc72002-08-10 06:26:31 +0000156 reliably) are also interrupted (as generally happens on for Linux/Unix.)
157 [SF bugs 231273, 439992 and 581232]
Mark Hammondc0e35152002-07-16 01:32:30 +0000158
Raymond Hettinger5a04aec2002-06-25 00:25:30 +0000159- Slices and repetitions of buffer objects now consistently return
160 a string. Formerly, strings would be returned most of the time,
161 but a buffer object would be returned when the repetition count
162 was one or when the slice range was all inclusive.
163
Walter Dörwald3430d702002-06-17 10:43:59 +0000164- Unicode objects in sys.path are no longer ignored but treated
165 as directory names.
166
Neal Norwitz1f68fc72002-06-14 00:50:42 +0000167- Fixed string.startswith and string.endswith builtin methods
168 so they accept negative indices. [SF bug 493951]
169
Guido van Rossumc5fe5eb2002-06-12 03:45:21 +0000170- Fixed a bug with a continue inside a try block and a yield in the
171 finally clause. [SF bug 567538]
172
Michael W. Hudson5efaf7e2002-06-11 10:55:12 +0000173- Most builtin sequences now support "extended slices", i.e. slices
Guido van Rossum2e82e712002-06-13 11:41:07 +0000174 with a third "stride" parameter. For example, "hello world"[::-1]
175 gives "dlrow olleh".
Michael W. Hudson5efaf7e2002-06-11 10:55:12 +0000176
Neal Norwitzd68f5172002-05-29 15:54:55 +0000177- A new warning PendingDeprecationWarning was added to provide
178 direction on features which are in the process of being deprecated.
179 The warning will not be printed by default. To see the pending
180 deprecations, use -Walways::PendingDeprecationWarning::
181 as a command line option or warnings.filterwarnings() in code.
182
Fred Draked0ba6362002-05-02 21:28:26 +0000183- Deprecated features of xrange objects have been removed as
184 promised. The start, stop, and step attributes and the tolist()
185 method no longer exist. xrange repetition and slicing have been
186 removed.
187
Guido van Rossum7dab2422002-04-26 19:40:56 +0000188- New builtin function enumerate(x), from PEP 279. Example:
189 enumerate("abc") is an iterator returning (0,"a"), (1,"b"), (2,"c").
190 The argument can be an arbitrary iterable object.
191
Neil Schemenauer89e3ee02002-04-26 01:58:53 +0000192- The assert statement no longer tests __debug__ at runtime. This means
193 that assert statements cannot be disabled by assigning a false value
194 to __debug__.
195
Walter Dörwald068325e2002-04-15 13:36:47 +0000196- A method zfill() was added to str and unicode, that fills a numeric
197 string to the left with zeros. For example,
198 "+123".zfill(6) -> "+00123".
199
Guido van Rossum862fe3c2002-04-15 12:36:47 +0000200- Complex numbers supported divmod() and the // and % operators, but
201 these make no sense. Since this was documented, they're being
202 deprecated now.
203
Guido van Rossum26dd8302002-04-26 20:11:29 +0000204- String and unicode methods lstrip(), rstrip() and strip() now take
205 an optional argument that specifies the characters to strip. For
206 example, "Foo!!!?!?!?".rstrip("?!") -> "Foo".
Guido van Rossum49042042002-04-13 00:59:05 +0000207
Guido van Rossumc69343b2002-04-12 19:22:48 +0000208- Added a new dict method pop(key). This removes and returns the
209 value corresponding to key. [SF patch #539949]
210
Guido van Rossum47834462002-04-04 15:21:33 +0000211- A new built-in type, bool, has been added, as well as built-in
212 names for its two values, True and False. Comparisons and sundry
213 other operations that return a truth value have been changed to
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000214 return a bool instead. Read PEP 285 for an explanation of why this
Guido van Rossum47834462002-04-04 15:21:33 +0000215 is backward compatible.
216
Guido van Rossum95b62a62002-03-29 01:07:24 +0000217- Fixed two bugs reported as SF #535905: under certain conditions,
218 deallocating a deeply nested structure could cause a segfault in the
219 garbage collector, due to interaction with the "trashcan" code;
220 access to the current frame during destruction of a local variable
221 could access a pointer to freed memory.
222
Guido van Rossumfe0ca4a2002-06-18 21:20:13 +0000223- The optional object allocator ("pymalloc") has been enabled by
224 default. The recommended practice for memory allocation and
225 deallocation has been streamlined. A header file is included,
226 Misc/pymemcompat.h, which can be bundled with 3rd party extensions
227 and lets them use the same API with Python versions from 1.5.2
228 onwards.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000229
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +0000230- PyErr_Display will provide file and line information for all exceptions
231 that have an attribute print_file_and_line, not just SyntaxErrors.
232
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000233- The UTF-8 codec will now encode and decode Unicode surrogates
234 correctly and without raising exceptions for unpaired ones.
235
Guido van Rossumadd88062002-08-15 14:01:14 +0000236- Universal newlines (PEP 278) is implemented. Briefly, using 'U'
237 instead of 'r' when opening a text file for reading changes the line
238 ending convention so that any of '\r', '\r\n', and '\n' is
239 recognized (even mixed in one file); all three are converted to
240 '\n', the standard Python line end character.
241
Neal Norwitz649b7592002-01-01 19:07:13 +0000242- file.xreadlines() now raises a ValueError if the file is closed:
243 Previously, an xreadlines object was returned which would raise
244 a ValueError when the xreadlines.next() method was called.
245
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000246- sys.exit() inadvertently allowed more than one argument.
Neal Norwitz0c766a02002-03-27 13:03:09 +0000247 An exception will now be raised if more than one argument is used.
248
Tim Petersaf8446f2001-12-21 21:36:50 +0000249Extension modules
250
Guido van Rossumb57089c2002-08-06 16:20:26 +0000251- The xreadlines module is slated for obsolescence.
252
Guido van Rossum79f0a102002-07-23 03:32:08 +0000253- The strptime function in the time module is now always available (a
254 Python implementation is used when the C library doesn't define it).
255
Guido van Rossum9562bcf2002-06-14 21:31:18 +0000256- The 'new' module is no longer an extension, but a Python module that
257 only exists for backwards compatibility. Its contents are no longer
258 functions but callable type objects.
259
Tim Peters81b92512002-04-29 01:37:32 +0000260- The bsddb.*open functions can now take 'None' as a filename.
Anthony Baxter83888952002-04-23 02:11:05 +0000261 This will create a temporary in-memory bsddb that won't be
Tim Peters81b92512002-04-29 01:37:32 +0000262 written to disk.
Anthony Baxter83888952002-04-23 02:11:05 +0000263
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000264- posix.lchown, posix.killpg, posix.mknod, and posix.getpgid have been
265 added where available.
Martin v. Löwis06a83e92002-04-14 10:19:44 +0000266
Martin v. Löwis2e64c342002-03-27 18:49:02 +0000267- The locale module now exposes the C library's gettext interface.
268
Tim Petersfbf74f22002-03-14 19:06:01 +0000269- A security hole ("double free") was found in zlib-1.1.3, a popular
270 third party compression library used by some Python modules. The
271 hole was quickly plugged in zlib-1.1.4, and the Windows build of
272 Python now ships with zlib-1.1.4.
273
Martin v. Löwis688357e2002-04-08 21:28:20 +0000274- pwd, grp, and resource return enhanced tuples now, with symbolic
275 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +0000276
Martin v. Löwis99866332002-03-01 10:27:01 +0000277- array.array is now a type object. A new format character
278 'u' indicates Py_UNICODE arrays. For those, .tounicode and
279 .fromunicode methods are available. Arrays now support __iadd__
280 and __imul__.
281
Neal Norwitze790eae2002-01-01 21:14:12 +0000282- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +0000283 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
284 is called.
285
Michael W. Hudson34f20ea2002-05-27 15:08:24 +0000286- signal.sigpending, signal.sigprocmask and signal.sigsuspend have
287 been added where available.
288
Tim Petersaf8446f2001-12-21 21:36:50 +0000289Library
290
Guido van Rossum4a57c332002-08-02 18:05:20 +0000291- New "algorithms" module: heapq, implements a heap queue. Thanks to
292 Kevin O'Connor for the code and François Pinard for an entertaining
293 write-up explaining the theory and practical uses of heaps.
294
Marc-André Lemburg58e2ff22002-07-12 14:40:04 +0000295- New encoding for the Palm OS character set: palmos.
296
Tim Peters943382c2002-07-07 03:59:34 +0000297- binascii.crc32() and the zipfile module had problems on some 64-bit
298 platforms. These have been fixed. On a platform with 8-byte C longs,
299 crc32() now returns a signed-extended 4-byte result, so that its value
300 as a Python int is equal to the value computed a 32-bit platform.
301
Martin v. Löwis7d650ca2002-06-30 15:05:00 +0000302- xml.dom.minidom.toxml and toprettyxml now take an optional encoding
303 argument.
304
Guido van Rossum9f7549b2002-06-10 21:39:42 +0000305- Some fixes in the copy module: when an object is copied through its
306 __reduce__ method, there was no check for a __setstate__ method on
307 the result [SF patch 565085]; deepcopy should treat instances of
308 custom metaclasses the same way it treats instances of type 'type'
309 [SF patch 560794].
310
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000311- Sockets now support timeout mode. After s.settimeout(T), where T is
312 a float expressing seconds, subsequent operations raise an exception
313 if they cannot be completed within T seconds. To disable timeout
Guido van Rossum79f0a102002-07-23 03:32:08 +0000314 mode, use s.settimeout(None). There's also a module function,
315 socket.setdefaulttimeout(T), which sets the default for all sockets
316 created henceforth.
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000317
318- getopt.gnu_getopt was added. This supports GNU-style option
319 processing, where options can be mixed with non-option arguments.
Martin v. Löwis446a25f2002-06-06 10:58:36 +0000320
Michael W. Hudsonb0dc1a32002-06-04 18:27:35 +0000321- Stop using strings for exceptions. String objects used for
322 exceptions are now classes deriving from Exception. The objects
323 changed were: Tkinter.TclError, bdb.BdbQuit, macpath.norm_error,
324 tabnanny.NannyNag, and xdrlib.Error.
Neal Norwitzb5b5a262002-06-04 17:14:07 +0000325
Walter Dörwald474458d2002-06-04 15:16:29 +0000326- Constants BOM_UTF8, BOM_UTF16, BOM_UTF16_LE, BOM_UTF16_BE,
327 BOM_UTF32, BOM_UTF32_LE and BOM_UTF32_BE that represent the Byte
328 Order Mark in UTF-8, UTF-16 and UTF-32 encodings for little and
329 big endian systems were added to the codecs module. The old names
330 BOM32_* and BOM64_* were off by a factor of 2.
331
Guido van Rossumf9257822002-06-18 20:43:18 +0000332- Added conversion functions math.degrees() and math.radians().
Raymond Hettinger87f59ee2002-05-13 04:17:32 +0000333
Raymond Hettinger9b1df1d2002-05-12 06:07:21 +0000334- ftplib.retrlines() now tests for callback is None rather than testing
335 for False. Was causing an error when given a callback object which
336 was callable but also returned len() as zero. The change may
337 create new breakage if the caller relied on the undocumented behavior
338 and called with callback set to [] or some other False value not
339 identical to None.
340
Tim Peters46c04e12002-05-05 20:40:00 +0000341- random.gauss() uses a piece of hidden state used by nothing else,
342 and the .seed() and .whseed() methods failed to reset it. In other
343 words, setting the seed didn't completely determine the sequence of
344 results produced by random.gauss(). It does now. Programs repeatedly
345 mixing calls to a seed method with calls to gauss() may see different
346 results now.
347
Fred Drake7f781c92002-05-01 20:33:53 +0000348- The pickle.Pickler class grew a clear_memo() method to mimic that
349 provided by cPickle.Pickler.
350
Tim Peters81b92512002-04-29 01:37:32 +0000351- difflib's SequenceMatcher class now does a dynamic analysis of
352 which elements are so frequent as to constitute noise. For
353 comparing files as sequences of lines, this generally works better
354 than the IS_LINE_JUNK function, and function ndiff's linejunk
355 argument defaults to None now as a result. A happy benefit is
356 that SequenceMatcher may run much faster now when applied
357 to large files with many duplicate lines (for example, C program
358 text with lots of repeated "}" and "return NULL;" lines).
359
Guido van Rossum256705b2002-04-23 13:29:43 +0000360- New Text.dump() method in Tkinter module.
361
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000362- New distutils commands for building packagers were added to
363 support pkgtool on Solaris and swinstall on HP-UX.
364
365- distutils now has a new abstract binary packager base class
366 command/bdist_packager, which simplifies writing packagers.
367 This will hopefully provide the missing bits to encourage
368 people to submit more packagers, e.g. for Debian, FreeBSD
369 and other systems.
370
Guido van Rossumf9257822002-06-18 20:43:18 +0000371- The UTF-16, -LE and -BE stream readers now raise a
372 NotImplementedError for all calls to .readline(). Previously, they
373 used to just produce garbage or fail with an encoding error --
374 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 +0000375 work well with these.
376
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000377- compileall now supports quiet operation.
378
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000379- The BaseHTTPServer now implements optional HTTP/1.1 persistent
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000380 connections.
381
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000382- socket module: the SSL support was broken out of the main
383 _socket module C helper and placed into a new _ssl helper
384 which now gets imported by socket.py if available and working.
385
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000386- encodings package: added aliases for all supported IANA character
387 sets
388
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000389- ftplib: to safeguard the user's privacy, anonymous login will use
390 "anonymous@" as default password, rather than the real user and host
391 name.
392
Fred Drake36736122002-01-10 13:50:31 +0000393- webbrowser: tightened up the command passed to os.system() so that
394 arbitrary shell code can't be executed because a bogus URL was
395 passed in.
396
Tim Peters11bd9942002-02-01 00:52:29 +0000397- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000398 gettext.find an optional all argument. Translations will now fallback
399 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000400
Martin v. Löwis9668b932002-01-12 11:27:42 +0000401- distutils bdist commands now offer a --skip-build option.
402
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000403- warnings.warn now accepts a Warning instance as first argument.
404
Fred Drakefed7e852002-04-04 19:36:15 +0000405- The xml.sax.expatreader.ExpatParser class will no longer create
406 circular references by using itself as the locator that gets passed
407 to the content handler implementation. [SF bug #535474]
408
Barry Warsaw47f3e2c2002-05-20 00:14:24 +0000409- The email.Parser.Parser class now properly parses strings regardless
410 of their line endings, which can be any of \r, \n, or \r\n (CR, LF,
411 or CRLF). Also, the Header class's constructor default arguments
412 has changed slightly so that an explicit maxlinelen value is always
413 honored.
414
Tim Petersaf8446f2001-12-21 21:36:50 +0000415Tools/Demos
416
Fred Drake40813b12002-08-05 15:24:19 +0000417- IDLE supports the new encoding declarations (PEP 263); it can also
418 deal with legacy 8-bit files if they use the locale's encoding. It
419 allows non-ASCII strings in the interactive shell and executes them
420 in the locale's encoding.
Martin v. Löwis98ce7b72002-08-05 15:11:26 +0000421
Marc-André Lemburg46260092002-04-04 16:17:11 +0000422- freeze.py now produces binaries which can import shared modules,
423 unlike before when this failed due to missing symbol exports in
424 the generated binary.
425
Tim Petersaf8446f2001-12-21 21:36:50 +0000426Build
427
Tim Petersf47630f2002-08-01 02:34:51 +0000428- The public Python C API will generally be declared using PyAPI_FUNC
Neal Norwitz1389f3e2002-07-22 13:21:10 +0000429 and PyAPI_DATA macros, while Python extension module init functions
430 will be declared with PyMODINIT_FUNC. DL_EXPORT/DL_IMPORT macros
431 are deprecated.
432
Tim Petersc6a3ff62002-07-08 22:11:52 +0000433- A bug was fixed that could cause COUNT_ALLOCS builds to segfault, or
434 get into infinite loops, when a new-style class got garbage-collected.
435 Unfortunately, to avoid this, the way COUNT_ALLOCS works requires
436 that new-style classes be immortal in COUNT_ALLOCS builds. Note that
437 COUNT_ALLOCS is not enabled by default, in either release or debug
438 builds, and that new-style classes are immortal only in COUNT_ALLOCS
439 builds.
440
Tim Peters943382c2002-07-07 03:59:34 +0000441- Compiling out the cyclic garbage collector is no longer an option.
442 The old symbol WITH_CYCLE_GC is now ignored, and Python.h arranges
443 that it's always defined (for the benefit of any extension modules
444 that may be conditionalizing on it). A bonus is that any extension
445 type participating in cyclic gc can choose to participate in the
446 Py_TRASHCAN mechanism now too; in the absence of cyclic gc, this used
447 to require editing the core to teach the trashcan mechanism about the
448 new type.
449
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000450- According to Annex F of the current C standard,
Tim Peters1de41bf2002-07-03 03:31:20 +0000451
452 The Standard C macro HUGE_VAL and its float and long double analogs,
453 HUGE_VALF and HUGE_VALL, expand to expressions whose values are
454 positive infinities.
455
456 Python only uses the double HUGE_VAL, and only to #define its own symbol
457 Py_HUGE_VAL. Some platforms have incorrect definitions for HUGE_VAL.
458 pyport.h used to try to worm around that, but the workarounds triggered
459 other bugs on other platforms, so we gave up. If your platform defines
460 HUGE_VAL incorrectly, you'll need to #define Py_HUGE_VAL to something
461 that works on your platform. The only instance of this I'm sure about
462 is on an unknown subset of Cray systems, described here:
463
464 http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm
465
466 Presumably 2.3a1 breaks such systems. If anyone uses such a system, help!
467
Martin v. Löwisa3fb4f72002-06-09 13:33:54 +0000468- The configure option --without-doc-strings can be used to remove the
469 doc strings from the builtin functions and modules; this reduces the
470 size of the executable.
471
Guido van Rossumadd88062002-08-15 14:01:14 +0000472- The universal newlines option (PEP 278) is on by default. On Unix
473 it can be disabled by passing --without-universal-newlines to the
474 configure script. On other platforms, remove
475 WITH_UNIVERSAL_NEWLINES from pyconfig.h.
Tim Peters639295f2002-04-21 07:30:30 +0000476
Martin v. Löwis1142de32002-03-29 16:28:31 +0000477- On Unix, a shared libpython2.3.so can be created with --enable-shared.
478
Tim Peters8deda702002-03-30 10:06:07 +0000479- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
480 preprocessor symbols were eliminated. The internal decisions they
481 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000482
Fred Drake7d28b732002-05-02 21:17:00 +0000483- The tools used to build the documentation now work under Cygwin as
484 well as Unix.
485
Skip Montanaro57454e52002-06-14 20:30:31 +0000486- The bsddb and dbm module builds have been changed to try and avoid version
487 skew problems and disable linkage with Berkeley DB 1.85 unless the
488 installer knows what s/he's doing. See the section on building these
489 modules in the README file for details.
490
Tim Petersaf8446f2001-12-21 21:36:50 +0000491C API
492
Guido van Rossumfdb86482002-08-14 21:20:32 +0000493- The Py_InitModule*() functions now accept NULL for the 'methods'
494 argument. Modules without global functions are becoming more common
495 now that factories can be types rather than functions.
496
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +0000497- New C API PyUnicode_FromOrdinal() which exposes unichr() at C
498 level.
499
Thomas Heller085358a2002-07-29 14:27:41 +0000500- New functions PyErr_SetExcFromWindowsErr() and
501 PyErr_SetExcFromWindowsErrWithFilename(). Similar to
502 PyErr_SetFromWindowsErrWithFilename() and
503 PyErr_SetFromWindowsErr(), but they allow to specify
504 the exception type to raise. Available on Windows.
505
Tim Peters7c321a82002-07-09 02:57:01 +0000506- Py_FatalError() is now declared as taking a const char* argument. It
507 was previously declared without const. This should not affect working
508 code.
509
Martin v. Löwis01f94bd2002-05-08 08:44:21 +0000510- Added new macro PySequence_ITEM(o, i) that directly calls
511 sq_item without rechecking that o is a sequence and without
512 adjusting for negative indices.
513
Fred Draked0ba6362002-05-02 21:28:26 +0000514- PyRange_New() now raises ValueError if the fourth argument is not 1.
515 This is part of the removal of deprecated features of the xrange
516 object.
517
Guido van Rossum517c7d42002-04-26 02:49:14 +0000518- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
519 coercion if both arguments have the same type but this type has the
520 CHECKTYPES flag set. This is to better support proxies.
521
Neil Schemenauer9344b142002-04-12 23:00:08 +0000522- The type of tp_free has been changed from "void (*)(PyObject *)" to
523 "void (*)(void *)".
524
525- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
526
Guido van Rossum0986d822002-04-08 01:38:42 +0000527- A type can now inherit its metatype from its base type. Previously,
528 when PyType_Ready() was called, if ob_type was found to be NULL, it
529 was always set to &PyType_Type; now it is set to base->ob_type,
530 where base is tp_base, defaulting to &PyObject_Type.
531
532- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
533
Neil Schemenauerc9abc1d2002-05-08 14:14:41 +0000534- The PyCore_* family of APIs have been removed.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000535
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000536- The "u#" parser marker will now pass through Unicode objects as-is
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000537 without going through the buffer API.
538
Martin v. Löwis7198a522002-01-01 19:59:11 +0000539- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
540
Tim Peters10a3bb52001-12-25 19:07:38 +0000541- An old #define of ANY as void has been removed from pyport.h. This
542 hasn't been used since Python's pre-ANSI days, and the #define has
543 been marked as obsolete since then. SF bug 495548 says it created
544 conflicts with other packages, so keeping it around wasn't harmless.
545
Tim Petersaf8446f2001-12-21 21:36:50 +0000546- Because Python's magic number scheme broke on January 1st, we decided
547 to stop Python development. Thanks for all the fish!
548
Tim Petersfb05db22002-03-11 00:24:00 +0000549- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000550 scheme to a new one. See Python/import.c for details.
551
Tim Petersaf8446f2001-12-21 21:36:50 +0000552New platforms
553
Martin v. Löwisf90ae202002-06-11 06:22:31 +0000554- AtheOS is now supported.
555
Andrew MacIntyre161ad0e2002-08-04 07:25:58 +0000556- the EMX runtime environment on OS/2 is now supported.
557
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000558- GNU/Hurd is now supported.
559
Tim Petersaf8446f2001-12-21 21:36:50 +0000560Tests
561
562Windows
563
Tim Peters08e72952002-04-16 20:48:01 +0000564- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
565 of that has been fixed in the installer (disabled Wise's "delete in-
566 use files" uninstall option).
567
Guido van Rossum181e41a2002-04-06 00:23:25 +0000568- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
569
Tim Peters33187922002-04-04 20:02:04 +0000570- The installer now installs Start menu shortcuts under (the local
571 equivalent of) "All Users" when doing an Admin install.
572
Tim Petersfb05db22002-03-11 00:24:00 +0000573- file.truncate([newsize]) now works on Windows for all newsize values.
574 It used to fail if newsize didn't fit in 32 bits, reflecting a
575 limitation of MS _chsize (which is no longer used).
576
Tim Petersab034fa2002-02-01 11:27:43 +0000577- os.waitpid() is now implemented for Windows, and can be used to block
578 until a specified process exits. This is similar to, but not exactly
579 the same as, os.waitpid() on POSIX systems. If you're waiting for
580 a specific process whose pid was obtained from one of the spawn()
581 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000582 See the docs for details. The docs were changed to clarify that
583 spawn functions return, and waitpid requires, a process handle on
584 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000585
Tim Peters11bd9942002-02-01 00:52:29 +0000586- New tempfile.TemporaryFile implementation for Windows: this doesn't
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000587 need a TemporaryFileWrapper wrapper anymore, and should be immune
Tim Peters11bd9942002-02-01 00:52:29 +0000588 to a nasty problem: before 2.3, if you got a temp file on Windows, it
589 got wrapped in an object whose close() method first closed the
590 underlying file, then deleted the file. This usually worked fine.
591 However, the spawn family of functions on Windows create (at a low C
592 level) the same set of open files in the spawned process Q as were
593 open in the spawning process P. If a temp file f was among them, then
594 doing f.close() in P first closed P's C-level file handle on f, but Q's
595 C-level file handle on f remained open, so the attempt in P to delete f
596 blew up with a "Permission denied" error (Windows doesn't allow
597 deleting open files). This was surprising, subtle, and difficult to
598 work around.
599
600- The os module now exports all the symbolic constants usable with the
601 low-level os.open() on Windows: the new constants in 2.3 are
602 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
603 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
604 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
605 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
606 (so specify both if you want both; note that neither is useful unless
607 specified with O_CREAT too).
608
Tim Petersaf8446f2001-12-21 21:36:50 +0000609Mac
610
611
Tim Peters909c0912001-12-14 23:16:18 +0000612What's New in Python 2.2 final?
613Release date: 21-Dec-2001
614===============================
615
616Type/class unification and new-style classes
617
Barry Warsaw52acb492001-12-21 20:04:22 +0000618- pickle.py, cPickle: allow pickling instances of new-style classes
619 with a custom metaclass.
620
Tim Peters909c0912001-12-14 23:16:18 +0000621Core and builtins
622
Barry Warsaw52acb492001-12-21 20:04:22 +0000623- weakref proxy object: when comparing, unwrap both arguments if both
624 are proxies.
625
Tim Peters909c0912001-12-14 23:16:18 +0000626Extension modules
627
Barry Warsaw52acb492001-12-21 20:04:22 +0000628- binascii.b2a_base64(): fix a potential buffer overrun when encoding
629 very short strings.
630
631- cPickle: the obscure "fast" mode was suspected of causing stack
632 overflows on the Mac. Hopefully fixed this by setting the recursion
633 limit much smaller. If the limit is too low (it only affects
634 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
635 when compiling cPickle.c (or in pyconfig.h).
636
Tim Peters909c0912001-12-14 23:16:18 +0000637Library
638
Barry Warsaw52acb492001-12-21 20:04:22 +0000639- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
640 close or delete time).
641
642- rfc822.py: fixed a bug where the address '<>' was converted to None
643 instead of an empty string (also fixes the email.Utils module).
644
645- xmlrpclib.py: version 1.0.0; uses precision for doubles.
646
647- test suite: the pickle and cPickle tests were not executing any code
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000648 when run from the standard regression test.
Barry Warsaw52acb492001-12-21 20:04:22 +0000649
Tim Peters909c0912001-12-14 23:16:18 +0000650Tools/Demos
651
652Build
653
654C API
655
656New platforms
657
658Tests
659
660Windows
661
Barry Warsaw52acb492001-12-21 20:04:22 +0000662- distutils package: fixed broken Windows installers (bdist_wininst).
663
664- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
665 instances are deleted at process exit time.
666
667- socket.py: prevent mysterious warnings when socket instances are
668 deleted at process exit time.
669
670- posixmodule.c: fix a Windows crash with stat() of a filename ending
671 in backslash.
672
Tim Peters909c0912001-12-14 23:16:18 +0000673Mac
674
Barry Warsaw52acb492001-12-21 20:04:22 +0000675- The Carbon toolbox modules have been upgraded to Universal Headers
676 3.4, and experimental CoreGraphics and CarbonEvents modules have
677 been added. All only for framework-enabled MacOSX.
678
Tim Peters909c0912001-12-14 23:16:18 +0000679
Tim Peters6272dfd2001-12-13 19:34:00 +0000680What's New in Python 2.2c1?
681Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000682===========================
683
684Type/class unification and new-style classes
685
Barry Warsaw06557452001-12-14 20:47:12 +0000686- Guido's tutorial introduction to the new type/class features has
687 been extensively updated. See
688
689 http://www.python.org/2.2/descrintro.html
690
691 That remains the primary documentation in this area.
692
Guido van Rossum33bab012001-12-05 22:45:48 +0000693- Fixed a leak: instance variables declared with __slots__ were never
694 deleted!
695
Guido van Rossum4b800852001-12-03 00:54:52 +0000696- The "delete attribute" method of descriptor objects is called
697 __delete__, not __del__. In previous releases, it was mistakenly
698 called __del__, which created an unfortunate overloading condition
699 with finalizers. (The "get attribute" and "set attribute" methods
700 are still called __get__ and __set__, respectively.)
701
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000702- Some subtle issues with the super built-in were fixed:
703
704 (a) When super itself is subclassed, its __get__ method would still
705 return an instance of the base class (i.e., of super).
706
707 (b) super(C, C()).__class__ would return C rather than super. This
708 is confusing. To fix this, I decided to change the semantics of
709 super so that it only applies to code attributes, not to data
710 attributes. After all, overriding data attributes is not
711 supported anyway.
712
713 (c) The __get__ method didn't check whether the argument was an
714 instance of the type used in creation of the super instance.
715
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000716- Previously, hash() of an instance of a subclass of a mutable type
717 (list or dictionary) would return some value, rather than raising
718 TypeError. This has been fixed. Also, directly calling
719 dict.__hash__ and list.__hash__ now raises the same TypeError
720 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000721
Guido van Rossumd331cb52001-12-05 19:46:42 +0000722- New-style objects now support deleting their __dict__. This is for
723 all intents and purposes equivalent to assigning a brand new empty
724 dictionary, but saves space if the object is not used further.
725
Tim Petersb3c9af12001-11-17 00:21:57 +0000726Core and builtins
727
Tim Peters3caca232001-12-06 06:23:26 +0000728- -Qnew now works as documented in PEP 238: when -Qnew is passed on
729 the command line, all occurrences of "/" use true division instead
730 of classic division. See the PEP for details. Note that "all"
731 means all instances in library and 3rd-party modules, as well as in
732 your own code. As the PEP says, -Qnew is intended for use only in
733 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000734 Note that test_coercion.py in the standard Python test suite fails
735 under -Qnew; this is expected, and won't be repaired until true
736 division becomes the default (in the meantime, test_coercion is
737 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000738
Fred Drake6c01e252001-12-14 17:08:12 +0000739- complex() now only allows the first argument to be a string
740 argument, and raises TypeError if either the second arg is a string
741 or if the second arg is specified when the first is a string.
742
Tim Petersb3c9af12001-11-17 00:21:57 +0000743Extension modules
744
Martin v. Löwis560da622001-11-24 09:24:51 +0000745- gc.get_referents was renamed to gc.get_referrers.
746
Tim Petersb3c9af12001-11-17 00:21:57 +0000747Library
748
Tim Peters25059d32001-12-07 20:35:43 +0000749- Functions in the os.spawn() family now release the global interpreter
750 lock around calling the platform spawn. They should always have done
751 this, but did not before 2.2c1. Multithreaded programs calling
752 an os.spawn function with P_WAIT will no longer block all Python threads
753 until the spawned program completes. It's possible that some programs
754 relies on blocking, although more likely by accident than by design.
755
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000756- webbrowser defaults to netscape.exe on OS/2 now.
757
Martin v. Löwis652e1912001-11-25 14:50:56 +0000758- Tix.ResizeHandle exposes detach_widget, hide, and show.
759
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000760- The charset alias windows_1252 has been added.
761
Barry Warsaw06557452001-12-14 20:47:12 +0000762- types.StringTypes is a tuple containing the defined string types;
763 usually this will be (str, unicode), but if Python was compiled
764 without Unicode support it will be just (str,).
765
766- The pulldom and minidom modules were synchronized to PyXML.
767
Tim Petersb3c9af12001-11-17 00:21:57 +0000768Tools/Demos
769
Barry Warsaw06557452001-12-14 20:47:12 +0000770- A new script called Tools/scripts/google.py was added, which fires
771 off a search on Google.
772
Tim Petersb3c9af12001-11-17 00:21:57 +0000773Build
774
Barry Warsaw06557452001-12-14 20:47:12 +0000775- Note that release builds of Python should arrange to define the
776 preprocessor symbol NDEBUG on the command line (or equivalent).
777 In the 2.2 pre-release series we tried to define this by magic in
778 Python.h instead, but it proved to cause problems for extension
779 authors. The Unix, Windows and Mac builds now all define NDEBUG in
780 release builds via cmdline (or equivalent) instead. Ports to
781 other platforms should do likewise.
782
Jack Jansen1999ef42001-12-06 21:47:20 +0000783- It is no longer necessary to use --with-suffix when building on a
784 case-insensitive file system (such as Mac OS X HFS+). In the build
785 directory an extension is used, but not in the installed python.
786
Tim Petersb3c9af12001-11-17 00:21:57 +0000787C API
788
Tim Petersf582b822001-12-11 18:51:08 +0000789- New function PyDict_MergeFromSeq2() exposes the builtin dict
790 constructor's logic for updating a dictionary from an iterable object
791 producing key-value pairs.
792
Tim Peterscffed4b2001-11-29 03:26:37 +0000793- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000794 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000795 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
796 dump core in some bad cases. This has been repaired. As a result,
797 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
798 previously went unchallenged.
799
Tim Petersb3c9af12001-11-17 00:21:57 +0000800New platforms
801
802Tests
803
804Windows
805
806Mac
807
Jack Jansenffa260f2001-12-06 21:14:00 +0000808- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
809 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000810
Barry Warsaw06557452001-12-14 20:47:12 +0000811- Changed logic for finding python home in Mac OS X framework Pythons.
812 Now sys.executable points to the executable again, in stead of to
813 the shared library. The latter is used only for locating the python
814 home.
815
816
Tim Peters84362bc2001-10-19 17:55:30 +0000817What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000818Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000819===========================
820
821Type/class unification and new-style classes
822
Guido van Rossum3d27df02001-11-15 20:27:54 +0000823- Multiple inheritance mixing new-style and classic classes in the
824 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000825
826 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000827 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000828
829 The MRO (method resolution order) for each base class is respected
830 according to its kind, but the MRO for the derived class is computed
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000831 using new-style MRO rules if any base class is a new-style class.
Tim Peters76f7fe32001-11-15 20:02:21 +0000832 This needs to be documented.
833
Tim Petersa427a2b2001-10-29 22:25:45 +0000834- The new builtin dictionary() constructor, and dictionary type, have
835 been renamed to dict. This reflects a decade of common usage.
836
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000837- dict() now accepts an iterable object producing 2-sequences. For
838 example, dict(d.items()) == d for any dictionary d. The argument,
839 and the elements of the argument, can be any iterable objects.
840
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000841- New-style classes can now have a __del__ method, which is called
842 when the instance is deleted (just like for classic classes).
843
Guido van Rossum12d955c2001-10-26 14:56:06 +0000844- Assignment to object.__dict__ is now possible, for objects that are
845 instances of new-style classes that have a __dict__ (unless the base
846 class forbids it).
847
Guido van Rossumc8e56452001-10-22 00:43:43 +0000848- Methods of built-in types now properly check for keyword arguments
849 (formerly these were silently ignored). The only built-in methods
850 that take keyword arguments are __call__, __init__ and __new__.
851
Guido van Rossum86443212001-10-27 22:28:54 +0000852- The socket function has been converted to a type; see below.
853
Tim Peters84362bc2001-10-19 17:55:30 +0000854Core and builtins
855
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000856- Assignment to __debug__ raises SyntaxError at compile-time. This
857 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000858 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000859
Guido van Rossum12d955c2001-10-26 14:56:06 +0000860- Clarified the error messages for unsupported operands to an operator
861 (like 1 + '').
862
Tim Peters84362bc2001-10-19 17:55:30 +0000863Extension modules
864
Tim Peters5ebfd362001-11-13 23:11:19 +0000865- mmap has a new keyword argument, "access", allowing a uniform way for
866 both Windows and Unix users to create read-only, write-through and
867 copy-on-write memory mappings. This was previously possible only on
868 Unix. A new keyword argument was required to support this in a
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000869 uniform way because the mmap() signatures had diverged across
Tim Peters5ebfd362001-11-13 23:11:19 +0000870 platforms. Thanks to Jay T Miller for repairing this!
871
Tim Peters169ded02001-11-03 19:57:21 +0000872- By default, the gc.garbage list now contains only those instances in
873 unreachable cycles that have __del__ methods; in 2.1 it contained all
874 instances in unreachable cycles. "Instances" here has been generalized
875 to include instances of both new-style and old-style classes.
876
Guido van Rossum12d955c2001-10-26 14:56:06 +0000877- The socket module defines a new method for socket objects,
878 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000879 send() until all data has been sent. Also, the socket function has
880 been converted to a subclassable type, like list and tuple (etc.)
881 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000882
883- Various bugfixes to the curses module. There is now a test suite
884 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000885
Guido van Rossum692adf12001-10-30 03:03:03 +0000886- binascii.b2a_base64 no longer places an arbitrary restriction of 57
887 bytes on its input.
888
Tim Peters84362bc2001-10-19 17:55:30 +0000889Library
890
Tim Peters5ebfd362001-11-13 23:11:19 +0000891- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000892 convenience function.
893
Tim Peters75335872001-11-03 19:35:43 +0000894- Symbolic group names in regular expressions must be unique. For
895 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
896 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000897 Python 2.2 detects this error at regexp compilation time;
898 previously, the error went undetected, and results were
899 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
900 pattern.subn() methods have been rewritten in C. Also, an
901 experimental function/method finditer() has been added, which works
902 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000903
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000904- Tix exposes more commands through the classes DirSelectBox,
905 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
906 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
907 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
908
Tim Peters98791af2001-10-23 01:59:54 +0000909- Traceback objects are now scanned by cyclic garbage collection, so
910 cycles created by casual use of sys.exc_info() no longer cause
911 permanent memory leaks (provided garbage collection is enabled).
912
Guido van Rossum49192142001-10-24 20:51:44 +0000913- os.extsep -- a new variable needed by the RISCOS support. It is the
914 separator used by extensions, and is '.' on all platforms except
915 RISCOS, where it is '/'. There is no need to use this variable
916 unless you have a masochistic desire to port your code to RISCOS.
917
Barry Warsaw012852b2001-11-16 16:17:27 +0000918- mimetypes.py has optional support for non-standard, but commonly
919 found types. guess_type() and guess_extension() now accept an
920 optional `strict' flag, defaulting to true, which controls whether
921 recognize non-standard types or not. A few non-standard types we
922 know about have been added. Also, when run as a script, there are
923 new -l and -e options.
924
925- statcache is now deprecated.
926
927- email.Utils.formatdate() now produces the preferred RFC 2822 style
928 dates with numeric timezones (it used to produce obsolete dates
929 hard coded to "GMT" timezone). An optional `localtime' flag is
930 added to produce dates in the local timezone, with daylight savings
931 time properly taken into account.
932
933- In pickle and cPickle, instead of masking errors in load() by
934 transforming them into SystemError, we let the original exception
935 propagate out. Also, implement support for __safe_for_unpickling__
936 in pickle, as it already was supported in cPickle.
937
Tim Peters84362bc2001-10-19 17:55:30 +0000938Tools/Demos
939
940Build
941
Barry Warsaw012852b2001-11-16 16:17:27 +0000942- The dbm module is built using libdb1 if available. The bsddb module
943 is built with libdb3 if available.
944
945- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
946
Tim Peters84362bc2001-10-19 17:55:30 +0000947C API
948
Tim Peters1fc240e2001-10-26 05:06:50 +0000949- New function PySequence_Fast_GET_SIZE() returns the size of a non-
950 NULL result from PySequence_Fast(), more quickly than calling
951 PySequence_Size().
952
Barry Warsaw012852b2001-11-16 16:17:27 +0000953- New argument unpacking function PyArg_UnpackTuple() added.
954
955- New functions PyObject_CallFunctionObjArgs() and
956 PyObject_CallMethodObjArgs() have been added to make it more
957 convenient and efficient to call functions and methods from C.
958
959- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
960 possible that this will propagate errors it didn't before.
961
962- New function PyObject_CheckReadBuffer(), which returns true if its
963 argument supports the single-segment readable buffer interface.
964
Tim Peters84362bc2001-10-19 17:55:30 +0000965New platforms
966
Guido van Rossum86443212001-10-27 22:28:54 +0000967- We've finally confirmed that this release builds on HP-UX 11.00,
968 *with* threads, and passes the test suite.
969
Tim Peters7a33d8b2001-11-05 02:51:07 +0000970- Thanks to a series of patches from Michael Muller, Python may build
971 again under OS/2 Visual Age C++.
972
Guido van Rossum49192142001-10-24 20:51:44 +0000973- Updated RISCOS port by Dietmar Schwertberger.
974
Tim Peters84362bc2001-10-19 17:55:30 +0000975Tests
976
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000977- Added a test script for the curses module. It isn't run automatically;
978 regrtest.py must be run with '-u curses' to enable it.
979
Tim Peters84362bc2001-10-19 17:55:30 +0000980Windows
981
Barry Warsaw012852b2001-11-16 16:17:27 +0000982Mac
983
984- PythonScript has been moved to unsupported and is slated to be
985 removed completely in the next release.
986
987- It should now be possible to build applets that work on both OS9 and
988 OSX.
989
990- The core is now linked with CoreServices not Carbon; as a side
991 result, default 8bit encoding on OSX is now ASCII.
992
993- Python should now build on OSX 10.1.1
994
Tim Peters84362bc2001-10-19 17:55:30 +0000995
Tim Petersabf925f2001-09-28 21:53:42 +0000996What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000997Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000998===========================
999
1000Type/class unification and new-style classes
1001
Guido van Rossum687ae002001-10-15 22:03:32 +00001002- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001003 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +00001004 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001005 remains: the __dict__ of a new-style class is a read-only proxy; you
1006 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +00001007 __defined__ attribute of new-style types no longer exists, for lack
1008 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001009 future a __cache__ may be resurrected with a similar function, if I
1010 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +00001011
Tim Peters1c9ca872001-10-04 06:43:12 +00001012- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
1013 always returned None, even when there was a class docstring).
1014
1015- doctest now finds and runs docstrings attached to new-style classes,
1016 class methods, static methods, and properties.
1017
Guido van Rossum9074ef62001-10-16 21:34:49 +00001018Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +00001019
Guido van Rossuma8bcf802001-10-15 15:53:58 +00001020- A very subtle syntactical pitfall in list comprehensions was fixed.
1021 For example: [a+b for a in 'abc', for b in 'def']. The comma in
1022 this example is a mistake. Previously, this would silently let 'a'
1023 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
1024 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
1025 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
1026 Note that [a for a in <singleton>] is a convoluted way to say
1027 [<singleton>] anyway, so it's not like any expressiveness is lost.
1028
Guido van Rossum9074ef62001-10-16 21:34:49 +00001029- getattr(obj, name, default) now only catches AttributeError, as
1030 documented, rather than returning the default value for all
1031 exceptions (which could mask bugs in a __getattr__ hook, for
1032 example).
1033
Fred Drakecb7a6b52001-10-22 18:41:51 +00001034- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +00001035 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001036 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +00001037 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +00001038
Guido van Rossum1c486092001-10-19 02:05:35 +00001039- unicode(obj) now behaves more like str(obj), accepting arbitrary
1040 objects, and calling a __unicode__ method if it exists.
1041 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +00001042 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +00001043
Barry Warsawf6fb1712001-10-19 05:35:40 +00001044- isinstance() now allows any object as the first argument and a
1045 class, a type or something with a __bases__ tuple attribute for the
1046 second argument. The second argument may also be a tuple of a
1047 class, type, or something with __bases__, in which case isinstance()
1048 will return true if the first argument is an instance of any of the
1049 things contained in the second argument tuple. E.g.
1050
1051 isinstance(x, (A, B))
1052
1053 returns true if x is an instance of A or B.
1054
Guido van Rossum9074ef62001-10-16 21:34:49 +00001055Extension modules
1056
1057- thread.start_new_thread() now returns the thread ID (previously None).
1058
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001059- binascii has now two quopri support functions, a2b_qp and b2a_qp.
1060
Guido van Rossumc524d952001-10-19 01:31:59 +00001061- readline now supports setting the startup_hook and the
1062 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +00001063
Guido van Rossumc524d952001-10-19 01:31:59 +00001064- os and posix supports chroot(), setgroups() and unsetenv() where
1065 available. The stat(), fstat(), statvfs() and fstatvfs() functions
1066 now return "pseudo-sequences" -- the various fields can now be
1067 accessed as attributes (e.g. os.stat("/").st_mtime) but for
1068 backwards compatibility they also behave as a fixed-length sequence.
1069 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +00001070 attributes.
1071
1072- time: localtime(), gmtime() and strptime() now return a
1073 pseudo-sequence similar to the os.stat() return value, with
1074 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +00001075
Guido van Rossum9074ef62001-10-16 21:34:49 +00001076- Decompression objects in the zlib module now accept an optional
1077 second parameter to decompress() that specifies the maximum amount
1078 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +00001079
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001080- optional SSL support in the socket module now exports OpenSSL
1081 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
1082 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +00001083 automatically seed its PRNG. Also, the keyfile and certfile
1084 arguments to socket.ssl() are now optional.
1085
1086- posixmodule (and by extension, the os module on POSIX platforms) now
1087 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001088
Guido van Rossum9074ef62001-10-16 21:34:49 +00001089Library
Guido van Rossum3c288632001-10-16 21:13:49 +00001090
Tim Peters7402f792001-10-02 03:53:41 +00001091- doctest now excludes functions and classes not defined by the module
1092 being tested, thanks to Tim Hochberg.
1093
Fred Drakecb7a6b52001-10-22 18:41:51 +00001094- HotShot, a new profiler implemented using a C-based callback, has
1095 been added. This substantially reduces the overhead of profiling,
1096 but it is still quite preliminary. Support modules and
1097 documentation will be added in upcoming releases (before 2.2 final).
1098
Guido van Rossumc4b09b42001-10-04 10:19:00 +00001099- profile now produces correct output in situations where an exception
1100 raised in Python is cleared by C code (e.g. hasattr()). This used
1101 to cause wrong output, including spurious claims of recursive
1102 functions and attribution of time spent to the wrong function.
1103
Tim Peters0a1fc4e2001-10-07 03:12:08 +00001104 The code and documentation for the derived OldProfile and HotProfile
1105 profiling classes was removed. The code hasn't worked for years (if
1106 you tried to use them, they raised exceptions). OldProfile
1107 intended to reproduce the behavior of the profiler Python used more
1108 than 7 years ago, and isn't interesting anymore. HotProfile intended
1109 to provide a faster profiler (but producing less information), and
1110 that's a worthy goal we intend to meet via a different approach (but
1111 without losing information).
1112
Tim Peterscce092d2001-10-09 05:31:56 +00001113- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +00001114 a much better system-specific calibration constant. The constant can
1115 now be specified in an instance constructor, or as a Profile class or
1116 instance variable, instead of by editing profile.py's source code.
1117 Calibration must still be done manually (see the docs for the profile
1118 module).
1119
1120 Note that Profile.calibrate() must be overriden by subclasses.
1121 Improving the accuracy required exploiting detailed knowledge of
1122 profiler internals; the earlier method abstracted away the details
1123 and measured a simplified model instead, but consequently computed
1124 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +00001125
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001126- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +00001127 which indicates whether output is intended for the header 'Q'
1128 encoding.
1129
Guido van Rossuma5343cc2001-10-18 18:02:07 +00001130- The SocketServer.ThreadingMixIn class now closes the request after
1131 finish_request() returns. (Not when it errors out though.)
1132
Barry Warsawf6fb1712001-10-19 05:35:40 +00001133- The nntplib module's NNTP.body() method has grown a `file' argument
1134 to allow saving the message body to a file.
1135
1136- The email package has added a class email.Parser.HeaderParser which
1137 only parses headers and does not recurse into the message's body.
1138 Also, the module/class MIMEAudio has been added for representing
1139 audio data (contributed by Anthony Baxter).
1140
1141- ftplib should be able to handle files > 2GB.
1142
1143- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
1144 ON, and OFF.
1145
Fred Drakecb7a6b52001-10-22 18:41:51 +00001146- xml.dom.minidom NodeList objects now support the length attribute
1147 and item() method as required by the DOM specifications.
1148
Guido van Rossumed554f62001-10-02 23:15:37 +00001149Tools/Demos
1150
1151- Demo/dns was removed. It no longer serves any purpose; a package
1152 derived from it is now maintained by Anthony Baxter, see
1153 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +00001154
Barry Warsawf6fb1712001-10-19 05:35:40 +00001155- The freeze tool has been made more robust, and two new options have
1156 been added: -X and -E.
1157
Tim Petersabf925f2001-09-28 21:53:42 +00001158Build
1159
Barry Warsawf6fb1712001-10-19 05:35:40 +00001160- configure will use CXX in LINKCC if CXX is used to build main() and
1161 the system requires to link a C++ main using the C++ compiler.
1162
Tim Petersabf925f2001-09-28 21:53:42 +00001163C API
1164
Guido van Rossum6c4bce32001-10-18 19:20:25 +00001165- The documentation for the tp_compare slot is updated to require that
1166 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
1167 not correct. This is not yet enforced but will be enforced in
1168 Python 2.3; even later, we may use -2 to indicate errors and +2 for
1169 "NotImplemented". Right now, -1 should be used for an error return.
1170
Tim Petersd38b1c72001-09-30 05:09:37 +00001171- PyLong_AsLongLong() now accepts int (as well as long) arguments.
1172 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
1173 as long) arguments.
1174
Guido van Rossum3c288632001-10-16 21:13:49 +00001175- PyThread_start_new_thread() now returns a long int giving the thread
1176 ID, if one can be calculated; it returns -1 for error, 0 if no
1177 thread ID is calculated (this is an incompatible change, but only
1178 the thread module used this API). This code has only really been
1179 tested on Linux and Windows; other platforms please beware (and
1180 report any bugs or strange behavior).
1181
Guido van Rossum1c486092001-10-19 02:05:35 +00001182- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
1183 input.
1184
Tim Petersabf925f2001-09-28 21:53:42 +00001185New platforms
1186
1187Tests
1188
1189Windows
1190
Tim Peters04cf1d32001-10-09 22:39:40 +00001191- Installer: If you install IDLE, and don't disable file-extension
1192 registration, a new "Edit with IDLE" context (right-click) menu entry
1193 is created for .py and .pyw files.
1194
Tim Peters1ce3cf72001-10-01 17:58:40 +00001195- The signal module now supports SIGBREAK on Windows, thanks to Steven
1196 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
1197 action remains to call Win32 ExitProcess(). This can be changed via
1198 signal.signal(). For example:
1199
1200 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
1201 # (SIGINT) behavior.
1202 import signal
1203 signal.signal(signal.SIGBREAK,
1204 signal.default_int_handler)
1205
1206 try:
1207 while 1:
1208 pass
1209 except KeyboardInterrupt:
1210 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
1211 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
1212 # program without the possibility for any Python-level cleanup).
1213 print "Clean exit"
1214
Tim Petersabf925f2001-09-28 21:53:42 +00001215
Tim Petersb07352e2001-09-08 01:25:47 +00001216What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001217Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +00001218===========================
1219
Guido van Rossum808eea72001-09-25 04:15:41 +00001220Type/class unification and new-style classes
1221
1222- pydoc and inspect are now aware of new-style classes;
1223 e.g. help(list) at the interactive prompt now shows proper
1224 documentation for all operations on list objects.
1225
1226- Applications using Jim Fulton's ExtensionClass module can now safely
1227 be used with Python 2.2. In particular, Zope 2.4.1 now works with
1228 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
1229 examples also work again. It is hoped that Gtk and Boost also work
1230 with 2.2a4 and beyond. (If you can confirm this, please write
1231 webmaster@python.org; if there are still problems, please open a bug
1232 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +00001233
Tim Peters66c1a522001-09-24 21:17:50 +00001234- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001235 These map to read-only attributes 'fget', 'fset', 'fdel', and '__doc__'
Tim Peters66c1a522001-09-24 21:17:50 +00001236 in the constructed property object. fget, fset and fdel weren't
1237 discoverable from Python in 2.2a3. __doc__ is new, and allows to
1238 associate a docstring with a property.
1239
Guido van Rossum808eea72001-09-25 04:15:41 +00001240- Comparison overloading is now more completely implemented. For
1241 example, a str subclass instance can properly be compared to a str
1242 instance, and it can properly overload comparison. Ditto for most
1243 other built-in object types.
1244
1245- The repr() of new-style classes has changed; instead of <type
1246 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
1247 *except* for built-in types, which are still rendered as <type
1248 'Foo'> (to avoid upsetting existing code that might parse or
1249 otherwise rely on repr() of certain type objects).
1250
1251- The repr() of new-style objects is now always <Foo object at XXX>;
1252 previously, it was sometimes <Foo instance at XXX>.
1253
1254- For new-style classes, what was previously called __getattr__ is now
1255 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001256 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +00001257 one in classic classes is defined which is called only if regular
1258 attribute access raises AttributeError; to catch *all* attribute
1259 access, you can use __getattribute__ (for new-style classes). If
1260 both are defined, __getattribute__ is called first, and if it raises
1261 AttributeError, __getattr__ is called.
1262
1263- The __class__ attribute of new-style objects can be assigned to.
1264 The new class must have the same C-level object layout as the old
1265 class.
1266
1267- The builtin file type can be subclassed now. In the usual pattern,
1268 "file" is the name of the builtin type, and file() is a new builtin
1269 constructor, with the same signature as the builtin open() function.
1270 file() is now the preferred way to open a file.
1271
1272- Previously, __new__ would only see sequential arguments passed to
1273 the type in a constructor call; __init__ would see both sequential
1274 and keyword arguments. This made no sense whatsoever any more, so
1275 now both __new__ and __init__ see all arguments.
1276
1277- Previously, hash() applied to an instance of a subclass of str or
1278 unicode always returned 0. This has been repaired.
1279
1280- Previously, an operation on an instance of a subclass of an
1281 immutable type (int, long, float, complex, tuple, str, unicode),
1282 where the subtype didn't override the operation (and so the
1283 operation was handled by the builtin type), could return that
1284 instance instead a value of the base type. For example, if s was of
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001285 a str subclass type, s[:] returned s as-is. Now it returns a str
Guido van Rossum808eea72001-09-25 04:15:41 +00001286 with the same value as s.
1287
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001288- Provisional support for pickling new-style objects has been added.
1289
Guido van Rossum808eea72001-09-25 04:15:41 +00001290Core
1291
Tim Peters2c9aa5e2001-09-23 04:06:05 +00001292- file.writelines() now accepts any iterable object producing strings.
1293
Marc-André Lemburgaefd7662001-09-20 12:59:37 +00001294- PyUnicode_FromEncodedObject() now works very much like
1295 PyObject_Str(obj) in that it tries to use __str__/tp_str
1296 on the object if the object is not a string or buffer. This
1297 makes unicode() behave like str() when applied to non-string/buffer
1298 objects.
1299
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001300- PyFile_WriteObject now passes Unicode objects to the file's write
1301 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +00001302 of a print statement must support Unicode objects, i.e. they must
1303 at least convert them into ASCII strings.
1304
Guido van Rossum624c8af2001-09-18 15:21:04 +00001305- Thread scheduling on Solaris should be improved; it is no longer
1306 necessary to insert a small sleep at the start of a thread in order
1307 to let other runnable threads be scheduled.
1308
Tim Petersb07352e2001-09-08 01:25:47 +00001309Library
1310
Marc-André Lemburgbf990172001-09-27 14:17:33 +00001311- StringIO.StringIO instances and cStringIO.StringIO instances support
1312 read character buffer compatible objects for their .write() methods.
1313 These objects are converted to strings and then handled as such
1314 by the instances.
1315
Barry Warsaw2f600732001-09-24 04:28:10 +00001316- The "email" package has been added. This is basically a port of the
1317 mimelib package <http://sf.net/projects/mimelib> with API changes
1318 and some implementations updated to use iterators and generators.
1319
Tim Peters8a9c2842001-09-22 21:30:22 +00001320- difflib.ndiff() and difflib.Differ.compare() are generators now. This
1321 restores the ability of Tools/scripts/ndiff.py to start producing output
1322 before the entire comparison is complete.
1323
Barry Warsaw58b072d2001-09-22 04:44:21 +00001324- StringIO.StringIO instances and cStringIO.StringIO instances support
1325 iteration just like file objects (i.e. their .readline() method is
1326 called for each iteration until it returns an empty string).
1327
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +00001328- The codecs module has grown four new helper APIs to access
1329 builtin codecs: getencoder(), getdecoder(), getreader(),
1330 getwriter().
1331
Guido van Rossum624c8af2001-09-18 15:21:04 +00001332- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
1333 simplifies writing XML RPC servers.
1334
Barry Warsaw647d5e82001-09-28 17:01:02 +00001335- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +00001336 after interpretation of symbolic links. On non-Unix systems, this
1337 is an alias for os.path.abspath().
1338
Tim Peters16a77ad2001-09-08 04:00:12 +00001339- operator.indexOf() (PySequence_Index() in the C API) now works with any
1340 iterable object.
1341
Guido van Rossum624c8af2001-09-18 15:21:04 +00001342- smtplib now supports various authentication and security features of
1343 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001344
Guido van Rossum624c8af2001-09-18 15:21:04 +00001345- hmac: a new module implementing keyed hashing for message
1346 authentication.
1347
1348- mimetypes now recognizes more extensions and file types. At the
1349 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001350
Guido van Rossum624c8af2001-09-18 15:21:04 +00001351- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001352 Python 2.2 bytecode generation. It has also been promoted from a
1353 Tool to a standard library package. (Tools/compiler still exists as
1354 a sample driver.)
1355
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001356Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +00001357
Tim Petersb07352e2001-09-08 01:25:47 +00001358Build
1359
Guido van Rossum624c8af2001-09-18 15:21:04 +00001360- Large file support (LFS) is now automatic when the platform supports
1361 it; no more manual configuration tweaks are needed. On Linux, at
1362 least, it's possible to have a system whose C library supports large
1363 files but whose kernel doesn't; in this case, large file support is
1364 still enabled but doesn't do you any good unless you upgrade your
1365 kernel or share your Python executable with another system whose
1366 kernel has large file support.
1367
1368- The configure script now supplies plausible defaults in a
1369 cross-compilation environment. This doesn't mean that the supplied
1370 values are always correct, or that cross-compilation now works
1371 flawlessly -- but it's a first step (and it shuts up most of
1372 autoconf's warnings about AC_TRY_RUN).
1373
1374- The Unix build is now a bit less chatty, courtesy of the parser
1375 generator. The build is completely silent (except for errors) when
1376 using "make -s", thanks to a -q option to setup.py.
1377
Tim Petersb07352e2001-09-08 01:25:47 +00001378C API
1379
Guido van Rossum624c8af2001-09-18 15:21:04 +00001380- The "structmember" API now supports some new flag bits to deny read
1381 and/or write access to attributes in restricted execution mode.
1382
Tim Petersb07352e2001-09-08 01:25:47 +00001383New platforms
1384
Guido van Rossum624c8af2001-09-18 15:21:04 +00001385- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1386 (http://familiar.handhelds.org).
1387
Tim Petersb07352e2001-09-08 01:25:47 +00001388Tests
1389
Tim Peters8a9c2842001-09-22 21:30:22 +00001390- The "classic" standard tests, which work by comparing stdout to
1391 an expected-output file under Lib/test/output/, no longer stop at
1392 the first mismatch. Instead the test is run to completion, and a
1393 variant of ndiff-style comparison is used to report all differences.
1394 This is much easier to understand than the previous style of reporting.
1395
1396- The unittest-based standard tests now use regrtest's test_main()
1397 convention, instead of running as a side-effect of merely being
1398 imported. This allows these tests to be run in more natural and
1399 flexible ways as unittests, outside the regrtest framework.
1400
1401- regrtest.py is much better integrated with unittest and doctest now,
1402 especially in regard to reporting errors.
1403
Tim Petersb07352e2001-09-08 01:25:47 +00001404Windows
1405
Guido van Rossum624c8af2001-09-18 15:21:04 +00001406- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001407 that support it (NTFS under Windows 2000). See "What's New in
1408 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001409
Tim Petersb07352e2001-09-08 01:25:47 +00001410
Tim Petersedc99312001-08-22 21:36:50 +00001411What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001412Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001413===========================
1414
1415Core
1416
Tim Peters9fffa3e2001-09-04 05:14:19 +00001417- Conversion of long to float now raises OverflowError if the long is too
1418 big to represent as a C double.
1419
Tim Peters32f453e2001-09-03 08:35:41 +00001420- The 3-argument builtin pow() no longer allows a third non-None argument
1421 if either of the first two arguments is a float, or if both are of
1422 integer types and the second argument is negative (in which latter case
1423 the arguments are converted to float, so this is really the same
1424 restriction).
1425
Tim Peters5d2b77c2001-09-03 05:47:38 +00001426- The builtin dir() now returns more information, and sometimes much
1427 more, generally naming all attributes of an object, and all attributes
1428 reachable from the object via its class, and from its class's base
1429 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1430 an empty list. In 2.2a3,
1431
1432 >>> dir([])
1433 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1434 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1435 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1436 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1437 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1438 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1439 'reverse', 'sort']
1440
1441 dir(module) continues to return only the module's attributes, though.
1442
Tim Petersbdee63f2001-09-02 03:40:59 +00001443- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001444 than raising OverflowError. This is a partial implementation of PEP
1445 237. You can use -Wdefault::OverflowWarning to enable a warning for
1446 this situation, and -Werror::OverflowWarning to revert to the old
1447 OverflowError exception.
1448
Guido van Rossum61c345f2001-09-04 03:26:15 +00001449- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001450 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001451 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1452 -Qold, meaning the / operator has its classic meaning and no
1453 warnings are issued. Using -Qwarn issues a run-time warning about
1454 all uses of classic division for int and long arguments; -Qwarnall
1455 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001456 (for use with fixdiv.py).
1457 [Note: the remainder of this paragraph (preserved below) became
1458 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1459 <obsolete>
1460 Using -Qnew is questionable; it turns on new division by default, but
1461 only in the __main__ module. You can usefully combine -Qwarn or
1462 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1463 warns about classic division everywhere else.
1464 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001465
Tim Petersbdee63f2001-09-02 03:40:59 +00001466- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001467 long, float, str, unicode, and tuple. (The types complex, list and
1468 dictionary can also be subclassed; this was introduced earlier.)
1469 Note that restrictions apply when subclassing immutable built-in
1470 types: you can only affect the value of the instance by overloading
1471 __new__. You can add mutable attributes, and the subclass instances
1472 will have a __dict__ attribute, but you cannot change the "value"
1473 (as implemented by the base class) of an immutable subclass instance
1474 once it is created.
1475
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001476- The dictionary constructor now takes an optional argument, a
1477 mapping-like object, and initializes the dictionary from its
1478 (key, value) pairs.
1479
Tim Petersbdee63f2001-09-02 03:40:59 +00001480- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001481 "cooperative super calls" in a multiple inheritance setting. For an
1482 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1483
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001484- A new built-in type, property, has been added. This enables the
1485 creation of "properties". These are attributes implemented by
1486 getter and setter functions (or only one of these for read-only or
1487 write-only attributes), without the need to override __getattr__.
1488 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001489
Tim Petersbdee63f2001-09-02 03:40:59 +00001490- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001491 liberalized, to allow leading zeroes. Examples of literals now
1492 legal that were SyntaxErrors before:
1493
1494 00.0 0e3 0100j 07.5 00000000000000000008.
1495
Tim Petersbdee63f2001-09-02 03:40:59 +00001496- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001497 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1498
Tim Petersedc99312001-08-22 21:36:50 +00001499Library
1500
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001501- telnetlib includes symbolic names for the options, and support for
1502 setting an option negotiation callback.
1503
Tim Petersa40c7932001-09-05 22:36:56 +00001504- The new C standard no longer requires that math libraries set errno to
1505 ERANGE on overflow. For platform libraries that exploit this new
1506 freedom, Python's overflow-checking was wholly broken. A new overflow-
1507 checking scheme attempts to repair that, but may not be reliable on all
1508 platforms (C doesn't seem to provide anything both useful and portable
1509 in this area anymore).
1510
Martin v. Löwis44f86962001-09-05 13:44:54 +00001511- Asynchronous timeout actions are available through the new class
1512 threading.Timer.
1513
Tim Peters78526162001-09-05 00:53:45 +00001514- math.log and math.log10 now return sensible results for even huge
1515 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1516
Tim Petersbdee63f2001-09-02 03:40:59 +00001517- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001518 currently held. See the docs for the imp module.
1519
Tim Petersbdee63f2001-09-02 03:40:59 +00001520- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001521 dumps containing ints written on platforms where Python ints are 8 bytes.
1522 When read on a box where Python ints are 4 bytes, such values are
1523 converted to Python longs.
1524
Tim Petersbdee63f2001-09-02 03:40:59 +00001525- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001526 code objects is no longer allowed. This plugs a security hole.
1527
Steve Purcell6091cd62001-09-06 16:05:17 +00001528- unittest.TestResult instances no longer store references to tracebacks
1529 generated by test failures. This prevents unexpected dangling references
1530 to objects that should be garbage collected between tests.
1531
Tim Petersedc99312001-08-22 21:36:50 +00001532Tools
1533
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001534- Tools/scripts/fixdiv.py has been added which can be used to fix
1535 division operators as per PEP 238.
1536
Tim Petersedc99312001-08-22 21:36:50 +00001537Build
1538
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001539- If you are an adventurous person using Mac OS X you may want to look at
1540 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1541 application, which can be used for experimenting with Carbon or Cocoa.
1542 Discussion of this on pythonmac-sig, please.
1543
Tim Peters7eea37e2001-09-04 22:08:56 +00001544C API
1545
1546- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001547
Tim Peters9fffa3e2001-09-04 05:14:19 +00001548- Note that PyLong_AsDouble can fail! This has always been true, but no
1549 callers checked for it. It's more likely to fail now, because overflow
1550 errors are properly detected now. The proper way to check:
1551
1552 double x = PyLong_AsDouble(some_long_object);
1553 if (x == -1.0 && PyErr_Occurred()) {
1554 /* The conversion failed. */
1555 }
1556
Tim Petersbdee63f2001-09-02 03:40:59 +00001557- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001558 compile but will not participate in GC. To upgrade an extension
1559 module:
1560
1561 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001562
Neil Schemenauer4042c692001-08-30 15:38:01 +00001563 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1564 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001565
Neil Schemenauer4042c692001-08-30 15:38:01 +00001566 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1567 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001568
Neil Schemenauer4042c692001-08-30 15:38:01 +00001569 - remove PyGC_HEAD_SIZE from object size calculations
1570
1571 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1572
Tim Petersbdee63f2001-09-02 03:40:59 +00001573- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001574 These can be used safely to construct string objects from a
1575 sprintf-style format string (similar to the format string supported
1576 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001577
Tim Petersedc99312001-08-22 21:36:50 +00001578New platforms
1579
Tim Petersb7da0902001-09-02 23:01:43 +00001580- Stephen Hansen contributed patches sufficient to get a clean compile
1581 under Borland C (Windows), but he reports problems running it and ran
1582 out of time to complete the port. Volunteers? Expect a MemoryError
1583 when importing the types module; this is probably shallow, and
1584 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001585
Tim Petersedc99312001-08-22 21:36:50 +00001586Tests
1587
1588Windows
1589
Tim Peters6e13a562001-09-06 00:32:15 +00001590- Large file support is now enabled on Win32 platforms as well as on
1591 Win64. This means that, for example, you can use f.tell() and f.seek()
1592 to manipulate files larger than 2 gigabytes (provided you have enough
1593 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001594 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1595 filesize limit, and large file support makes no difference there.
1596 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1597 NTFS has no practical limit on file size, and files of any size can be
1598 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001599
Tim Petersbdee63f2001-09-02 03:40:59 +00001600- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001601 points to command.com (patch from Brian Quinlan).
1602
Tim Petersedc99312001-08-22 21:36:50 +00001603
Tim Peters20f51a72001-07-21 02:31:40 +00001604What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001605Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001606===========================
1607
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001608Build
1609
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001610- Tim Peters developed a brand new Windows installer using Wise 8.1,
1611 generously donated to us by Wise Solutions.
1612
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001613- configure supports a new option --enable-unicode, with the values
1614 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1615 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001616
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001617- A new configure option --enable-framework builds a Mac OS X framework,
1618 which "make frameworkinstall" will install. This provides a starting
1619 point for more mac-like functionality, join pythonmac-sig@python.org
1620 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001621
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001622- The NeXT platform is no longer supported.
1623
1624- The `new' module is now statically linked.
1625
Tim Peters0afb6092001-08-15 06:06:44 +00001626Tools
1627
1628- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001629 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001630 the module docstring for details.
1631
Tim Peters20f51a72001-07-21 02:31:40 +00001632Tests
1633
Tim Peters5e824c32001-08-12 22:25:01 +00001634- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001635 platforms, allowing to give clearer test result output. regrtest
1636 also has optional --use/-u switch to run normally disabled tests
1637 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001638
Tim Peters20f51a72001-07-21 02:31:40 +00001639- Several new tests in the standard test suite, with special thanks to
1640 Nick Mathewson.
1641
1642Core
1643
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001644- The floor division operator // has been added as outlined in PEP
1645 238. The / operator still provides classic division (and will until
1646 Python 3.0) unless "from __future__ import division" is included, in
1647 which case the / operator will provide true division. The operator
1648 module provides truediv() and floordiv() functions. Augmented
1649 assignment variants are included, as are the equivalent overloadable
1650 methods and C API methods. See the PEP for a full discussion:
1651 <http://python.sf.net/peps/pep-0238.html>
1652
Tim Peters6cd6a822001-08-17 22:11:27 +00001653- Future statements are now effective in simulated interactive shells
1654 (like IDLE). This should "just work" by magic, but read Michael
1655 Hudson's "Future statements in simulated shells" PEP 264 for full
1656 details: <http://python.sf.net/peps/pep-0264.html>.
1657
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001658- The type/class unification (PEP 252-253) was integrated into the
1659 trunk and is not so tentative any more (the exact specification of
1660 some features is still tentative). A lot of work has done on fixing
1661 bugs and adding robustness and features (performance still has to
1662 come a long way).
1663
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001664- Warnings about a mismatch in the Python API during extension import
1665 now use the Python warning framework (which makes it possible to
1666 write filters for these warnings).
1667
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001668- A function's __dict__ (aka func_dict) will now always be a
1669 dictionary. It used to be possible to delete it or set it to None,
1670 but now both actions raise TypeErrors. It is still legal to set it
1671 to a dictionary object. Getting func.__dict__ before any attributes
1672 have been assigned now returns an empty dictionary instead of None.
1673
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001674- A new command line option, -E, was added which disables the use of
1675 all environment variables, or at least those that are specifically
1676 significant to Python. Usually those have a name starting with
1677 "PYTHON". This was used to fix a problem where the tests fail if
1678 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1679 older distribution.
1680
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001681Library
1682
Tim Peters5e824c32001-08-12 22:25:01 +00001683- New class Differ and new functions ndiff() and restore() in difflib.py.
1684 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001685 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001686
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001687- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1688 value using the minimal quoting required for the value; more
1689 reliable than using xml.sax.saxutils.escape() for attribute values.
1690
1691- Readline completion support for cmd.Cmd was added.
1692
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001693- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1694
1695- Added function threading.BoundedSemaphore()
1696
1697- Added Ka-Ping Yee's cgitb.py module.
1698
1699- The `new' module now exposes the CO_xxx flags.
1700
Martin v. Löwis560da622001-11-24 09:24:51 +00001701- The gc module offers the get_referents function.
1702
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001703New platforms
1704
1705C API
1706
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001707- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1708 which provide a cross-platform implementations for the
1709 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1710 the standard sprintf() and vsprintf() C lib APIs, these versions
1711 apply bounds checking on the used buffer which enhances protection
1712 against buffer overruns.
1713
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001714- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001715 and extensions using different Unicode widths is rendered next to
1716 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001717 will result in an ImportError. Unicode extensions writers must make
1718 sure to check the Unicode width compatibility in their extensions by
1719 using at least one of the mangled Unicode APIs in the extension.
1720
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001721- Two new flags METH_NOARGS and METH_O are available in method definition
1722 tables to simplify implementation of methods with no arguments and a
1723 single untyped argument. Calling such methods is more efficient than
1724 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1725 deprecated.
1726
Tim Petersc1731372001-08-04 08:12:36 +00001727Windows
1728
1729- "import module" now compiles module.pyw if it exists and nothing else
1730 relevant is found.
1731
Tim Peters20f51a72001-07-21 02:31:40 +00001732
Guido van Rossum55a78992001-07-17 17:22:32 +00001733What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001734Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001735===========================
1736
1737Core
Tim Petersa814db52001-05-14 07:05:58 +00001738
Tim Peters6d6c1a32001-08-02 04:15:00 +00001739- TENTATIVELY, a large amount of code implementing much of what's
1740 described in PEP 252 (Making Types Look More Like Classes) and PEP
1741 253 (Subtyping Built-in Types) was added. This will be released
1742 with Python 2.2a1. Documentation will be provided separately
1743 through http://www.python.org/2.2/. The purpose of releasing this
1744 with Python 2.2a1 is to test backwards compatibility. It is
1745 possible, though not likely, that a decision is made not to release
1746 this code as part of 2.2 final, if any serious backwards
1747 incompapatibilities are found during alpha testing that cannot be
1748 repaired.
1749
Guido van Rossum55a78992001-07-17 17:22:32 +00001750- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001751 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001752 more 'yield' statements. See PEP 255. Since this adds a new
1753 keyword to the language, this feature must be enabled by including a
1754 future statement: "from __future__ import generators" (see PEP 236).
1755 Generators will become a standard feature in a future release
1756 (probably 2.3). Without this future statement, 'yield' remains an
1757 ordinary identifier, but a warning is issued each time it is used.
1758 (These warnings currently don't conform to the warnings framework of
1759 PEP 230; we intend to fix this in 2.2a2.)
1760
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001761- The UTF-16 codec was modified to be more RFC compliant. It will now
1762 only remove BOM characters at the start of the string and then
1763 only if running in native mode (UTF-16-LE and -BE won't remove a
1764 leading BMO character).
1765
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001766- Strings now have a new method .decode() to complement the already
1767 existing .encode() method. These two methods provide direct access
1768 to the corresponding decoders and encoders of the registered codecs.
1769
1770 To enhance the usability of the .encode() method, the special
1771 casing of Unicode object return values was dropped (Unicode objects
1772 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001773
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001774 Both methods will now return whatever the codec in charge of the
1775 requested encoding returns as object, e.g. Unicode codecs will
1776 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1777 will return u"äöü"). This enables codec writer to create codecs
1778 for various simple to use conversions.
1779
1780 New codecs were added to demonstrate these new features (the .encode()
1781 and .decode() columns indicate the type of the returned objects):
1782
1783 Name | .encode() | .decode() | Description
1784 ----------------------------------------------------------------------
1785 uu | string | string | UU codec (e.g. for email)
1786 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001787 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001788 zlib | string | string | zlib compression
1789 hex | string | string | 2-byte hex codec
1790 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1791
Mark Hammond2a0af792001-05-14 03:09:36 +00001792- Some operating systems now support the concept of a default Unicode
1793 encoding for file system operations. Notably, Windows supports 'mbcs'
1794 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001795 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001796 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001797
1798 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001799 functions that return filenames (such as os.listdir()) to return Python
1800 string objects pre-encoded using the default file system encoding for
1801 the platform. As this encoding is likely to be different from Python's
1802 default encoding, converting this name to a Unicode object before passing
1803 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001804 would attempt to use its default encoding (generally ASCII) rather than
1805 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001806
Tim Petersa814db52001-05-14 07:05:58 +00001807 In general, this change simply removes surprises when working with
1808 Unicode and the file system, making these operations work as you expect,
1809 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001810 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001811
Tim Peters61dff2b2001-05-08 15:43:37 +00001812- Float (and complex) literals in source code were evaluated to full
1813 precision only when running from a .py file; the same code loaded from a
1814 .pyc (or .pyo) file could suffer numeric differences starting at about the
1815 12th significant decimal digit. For example, on a machine with IEEE-754
1816 floating arithmetic,
1817
1818 x = 9007199254740992.0
1819 print long(x)
1820
1821 printed 9007199254740992 if run directly from .py, but 9007199254740000
1822 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1823 str(float) instead of repr(float) when building code objects. marshal
1824 now uses repr(float) instead, which should reproduce floats to full
1825 machine precision (assuming the platform C float<->string I/O conversion
1826 functions are of good quality).
1827
1828 This may cause floating-point results to change in some cases, and
1829 usually for the better, but may also cause numerically unstable
1830 algorithms to break.
1831
Tim Peters2f228e72001-05-13 00:19:31 +00001832- The implementation of dicts suffers fewer collisions, which has speed
1833 benefits. However, the order in which dict entries appear in dict.keys(),
1834 dict.values() and dict.items() may differ from previous releases for a
1835 given dict. Nothing is defined about this order, so no program should
1836 rely on it. Nevertheless, it's easy to write test cases that rely on the
1837 order by accident, typically because of printing the str() or repr() of a
1838 dict to an "expected results" file. See Lib/test/test_support.py's new
1839 sortdict(dict) function for a simple way to display a dict in sorted
1840 order.
1841
Tim Peters7a3bfc32001-06-12 01:22:22 +00001842- Many other small changes to dicts were made, resulting in faster
1843 operation along the most common code paths.
1844
Guido van Rossum10315822001-05-01 20:54:30 +00001845- Dictionary objects now support the "in" operator: "x in dict" means
1846 the same as dict.has_key(x).
1847
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001848- The update() method of dictionaries now accepts generic mapping
1849 objects. Specifically the argument object must support the .keys()
1850 and __getitem__() methods. This allows you to say, for example,
1851 {}.update(UserDict())
1852
Guido van Rossum10315822001-05-01 20:54:30 +00001853- Iterators were added; this is a generalized way of providing values
1854 to a for loop. See PEP 234. There's a new built-in function iter()
1855 to return an iterator. There's a new protocol to get the next value
1856 from an iterator using the next() method (in Python) or the
1857 tp_iternext slot (in C). There's a new protocol to get iterators
1858 using the __iter__() method (in Python) or the tp_iter slot (in C).
1859 Iterating (i.e. a for loop) over a dictionary generates its keys.
1860 Iterating over a file generates its lines.
1861
Tim Petersf553f892001-05-01 20:45:31 +00001862- The following functions were generalized to work nicely with iterator
1863 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001864 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001865 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1866 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001867 join() method of strings
1868 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001869 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1870 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001871 right-hand side of assignment statements with multiple targets, such as
1872 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001873
Tim Petersd85e1022001-05-11 21:51:48 +00001874- Accessing module attributes is significantly faster (for example,
1875 random.random or os.path or yourPythonModule.yourAttribute).
1876
Tim Peterse63415e2001-05-08 04:38:29 +00001877- Comparing dictionary objects via == and != is faster, and now works even
1878 if the keys and values don't support comparisons other than ==.
1879
Tim Peters95bf9392001-05-10 08:32:44 +00001880- Comparing dictionaries in ways other than == and != is slower: there were
1881 insecurities in the dict comparison implementation that could cause Python
1882 to crash if the element comparison routines for the dict keys and/or
1883 values mutated the dicts. Making the code bulletproof slowed it down.
1884
Tim Peterseb28ef22001-06-02 05:27:19 +00001885- Collisions in dicts are resolved via a new approach, which can help
1886 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001887 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001888 faster now. Thanks to Christian Tismer for pointing out the cause and
1889 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001890
Tim Peters52e155e2001-06-16 05:42:57 +00001891- repr() is much faster for large containers (dict, list, tuple).
1892
1893
Tim Petersa814db52001-05-14 07:05:58 +00001894Library
1895
Fred Drake960fdf92001-07-20 18:38:26 +00001896- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1897 were added to the string module. These a locale-indenpendent
1898 constants, unlike letters, lowercase, and uppercase. These are now
1899 use in appropriate locations in the standard library.
1900
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001901- The flags used in dlopen calls can now be configured using
1902 sys.setdlopenflags and queried using sys.getdlopenflags.
1903
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001904- Fredrik Lundh's xmlrpclib is now a standard library module. This
1905 provides full client-side XML-RPC support. In addition,
1906 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1907 one asyncore-based). Thanks to Eric Raymond for the documentation.
1908
Guido van Rossum643d3912001-07-05 14:46:25 +00001909- The xrange() object is simplified: it no longer supports slicing,
1910 repetition, comparisons, efficient 'in' checking, the tolist()
1911 method, or the start, stop and step attributes. See PEP 260.
1912
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001913- A new function fnmatch.filter to filter lists of file names was added.
1914
Barry Warsawffd674d2001-05-22 16:00:10 +00001915- calendar.py uses month and day names based on the current locale.
1916
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001917- strop is now *really* obsolete (this was announced before with 1.6),
1918 and issues DeprecationWarning when used (except for the four items
1919 that are still imported into string.py).
1920
Tim Petersa814db52001-05-14 07:05:58 +00001921- Cookie.py now sorts key+value pairs by key in output strings.
1922
1923- pprint.isrecursive(object) didn't correctly identify recursive objects.
1924 Now it does.
1925
Tim Peters95b3f782001-05-14 18:39:41 +00001926- pprint functions now much faster for large containers (tuple, list, dict).
1927
Tim Peters7b9542a2001-06-10 23:40:19 +00001928- New 'q' and 'Q' format codes in the struct module, corresponding to C
1929 types "long long" and "unsigned long long" (on Windows, __int64). In
1930 native mode, these can be used only when the platform C compiler supports
1931 these types (when HAVE_LONG_LONG is #define'd by the Python config
1932 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001933 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1934 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001935
Guido van Rossum83213cc2001-06-12 16:48:52 +00001936- The site module installs a new built-in function 'help' that invokes
1937 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1938 it displays a message reminding the user to use 'help()' or
1939 'help(object)'.
1940
Tim Petersa814db52001-05-14 07:05:58 +00001941Tests
1942
1943- New test_mutants.py runs dict comparisons where the key and value
1944 comparison operators mutute the dicts randomly during comparison. This
1945 rapidly causes Python to crash under earlier releases (not for the faint
1946 of heart: it can also cause Win9x to freeze or reboot!).
1947
1948- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001949 pprint.isreadable() return sensible results. Also verifies that simple
1950 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001951
Tim Peters4324aa32001-05-28 22:30:08 +00001952C API
1953
1954- Removed the unused last_is_sticky argument from the internal
1955 _PyTuple_Resize(). If this affects you, you were cheating.
1956
1957
Guido van Rossum55a78992001-07-17 17:22:32 +00001958======================================================================
1959
1960
Guido van Rossumffe13be2001-04-16 18:46:45 +00001961What's New in Python 2.1 (final)?
1962=================================
1963
1964We only changed a few things since the last release candidate, all in
1965Python library code:
1966
1967- A bug in the locale module was fixed that affected locales which
1968 define no grouping for numeric formatting.
1969
1970- A few bugs in the weakref module's implementations of weak
1971 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1972 and the test suite was updated to check for these bugs.
1973
1974- An old bug in the os.path.walk() function (introduced in Python
1975 2.0!) was fixed: a non-existent file would cause an exception
1976 instead of being ignored.
1977
1978- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1979 PyChecker.
1980
1981
Guido van Rossum5b08f132001-04-16 02:05:23 +00001982What's New in Python 2.1c2?
1983===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001984
Guido van Rossum5b08f132001-04-16 02:05:23 +00001985A flurry of small changes, and one showstopper fixed in the nick of
1986time made it necessary to release another release candidate. The list
1987here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001988
Guido van Rossum5b08f132001-04-16 02:05:23 +00001989Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001990
Guido van Rossum5b08f132001-04-16 02:05:23 +00001991- Tim discovered a nasty bug in the dictionary code, caused by
1992 PyDict_Next() calling dict_resize(), and the GC code's use of
1993 PyDict_Next() violating an assumption in dict_items(). This was
1994 fixed with considerable amounts of band-aid, but the net effect is a
1995 saner and more robust implementation.
1996
1997- Made a bunch of symbols static that were accidentally global.
1998
1999Build and Ports
2000
2001- The setup.py script didn't check for a new enough version of zlib
2002 (1.1.3 is needed). Now it does.
2003
2004- Changed "make clean" target to also remove shared libraries.
2005
2006- Added a more general warning about the SGI Irix optimizer to README.
2007
2008Library
2009
2010- Fix a bug in urllib.basejoin("http://host", "../file.html") which
2011 omitted the slash between host and file.html.
2012
2013- The mailbox module's _Mailbox class contained a completely broken
2014 and undocumented seek() method. Ripped it out.
2015
2016- Fixed a bunch of typos in various library modules (urllib2, smtpd,
2017 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
2018
2019- Fixed a few last-minute bugs in unittest.
2020
2021Extensions
2022
2023- Reverted the patch to the OpenSSL code in socketmodule.c to support
2024 RAND_status() and the EGD, and the subsequent patch that tried to
2025 fix it for pre-0.9.5 versions; the problem with the patch is that on
2026 some systems it issues a warning whenever socket is imported, and
2027 that's unacceptable.
2028
2029Tests
2030
2031- Fixed the pickle tests to work with "import test.test_pickle".
2032
2033- Tweaked test_locale.py to actually run the test Windows.
2034
2035- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
2036 not "wb" (which is not a valid mode at all).
2037
2038- Fix pstats browser crashes. Import readline if it exists to make
2039 the user interface nicer.
2040
2041- Add "import thread" to the top of test modules that import the
2042 threading module (test_asynchat and test_threadedtempfile). This
2043 prevents test failures caused by a broken threading module resulting
2044 from a previously caught failed import.
2045
2046- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
2047 needed on some platforms (e.g. Solaris 8) when the tests are run
2048 twice in succession.
2049
2050- Skip rather than fail test_sunaudiodev if no audio device is found.
2051
2052
2053What's New in Python 2.1c1?
2054===========================
2055
2056This list was significantly updated when 2.1c2 was released; the 2.1c1
2057release didn't mention most changes that were actually part of 2.1c1:
2058
2059Legal
2060
2061- Copyright was assigned to the Python Software Foundation (PSF) and a
2062 PSF license (very similar to the CNRI license) was added.
2063
2064- The CNRI copyright notice was updated to include 2001.
2065
2066Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00002067
Guido van Rossumc9932722001-04-12 02:31:27 +00002068- After a public outcry, assignment to __debug__ is no longer illegal;
2069 instead, a warning is issued. It will become illegal in 2.2.
2070
Guido van Rossum5b08f132001-04-16 02:05:23 +00002071- Fixed a core dump with "%#x" % 0, and changed the semantics so that
2072 "%#x" now always prepends "0x", even if the value is zero.
2073
2074- Fixed some nits in the bytecode compiler.
2075
2076- Fixed core dumps when calling certain kinds of non-functions.
2077
2078- Fixed various core dumps caused by reference count bugs.
2079
2080Build and Ports
2081
2082- Use INSTALL_SCRIPT to install script files.
2083
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002084- New port: SCO Unixware 7, by Billy G. Allie.
2085
Guido van Rossum5b08f132001-04-16 02:05:23 +00002086- Updated RISCOS port.
2087
2088- Updated BeOS port and notes.
2089
2090- Various other porting problems resolved.
2091
2092Library
2093
2094- The TERMIOS and SOCKET modules are now truly obsolete and
2095 unnecessary. Their symbols are incorporated in the termios and
2096 socket modules.
2097
2098- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
2099 better tests for pickling.
2100
2101- threading: make Condition.wait() robust against KeyboardInterrupt.
2102
2103- zipfile: add support to zipfile to support opening an archive
2104 represented by an open file rather than a file name. Fix bug where
2105 the archive was not properly closed. Fixed a bug in this bugfix
2106 where flush() was called for a read-only file.
2107
2108- imputil: added an uninstall() method to the ImportManager.
2109
2110- Canvas: fixed bugs in lower() and tkraise() methods.
2111
2112- SocketServer: API change (added overridable close_request() method)
2113 so that the TCP server can explicitly close the request.
2114
2115- pstats: Eric Raymond added a simple interactive statistics browser,
2116 invoked when the module is run as a script.
2117
2118- locale: fixed a problem in format().
2119
2120- webbrowser: made it work when the BROWSER environment variable has a
2121 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
2122 KDE 2. Fixed some other nits.
2123
2124- unittest: changes to allow using a different exception than
2125 AssertionError, and added a few more function aliases. Some other
2126 small changes.
2127
2128- urllib, urllib2: fixed redirect problems and a coupleof other nits.
2129
2130- asynchat: fixed a critical bug in asynchat that slipped through the
2131 2.1b2 release. Fixed another rare bug.
2132
2133- Fix some unqualified except: clauses (always a bad code example).
2134
2135XML
2136
2137- pyexpat: new API get_version_string().
2138
2139- Fixed some minidom bugs.
2140
2141Extensions
2142
2143- Fixed a core dump in _weakref. Removed the weakref.mapping()
2144 function (it adds nothing to the API).
2145
2146- Rationalized the use of header files in the readline module, to make
2147 it compile (albeit with some warnings) with the very recent readline
2148 4.2, without breaking for earlier versions.
2149
2150- Hopefully fixed a buffering problem in linuxaudiodev.
2151
2152- Attempted a fix to make the OpenSSL support in the socket module
2153 work again with pre-0.9.5 versions of OpenSSL.
2154
2155Tests
2156
2157- Added a test case for asynchat and asyncore.
2158
2159- Removed coupling between tests where one test failing could break
2160 another.
2161
2162Tools
2163
2164- Ping added an interactive help browser to pydoc, fixed some nits
2165 in the rest of the pydoc code, and added some features to his
2166 inspect module.
2167
2168- An updated python-mode.el version 4.1 which integrates Ken
2169 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
2170 much nicer in XEmacs and Emacs. When stepping through your program
2171 with pdb, in either the shell window or the *Python* window, the
2172 source file and line will be tracked by an arrow. Very cool!
2173
2174- IDLE: syntax warnings in interactive mode are changed into errors.
2175
2176- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00002177 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00002178
2179- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002180
Barry Warsaw11e89c72001-04-11 20:37:57 +00002181
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002182What's New in Python 2.1 beta 2?
2183================================
2184
Guido van Rossum053ae352001-03-22 14:17:21 +00002185(Unlisted are many fixed bugs, more documentation, etc.)
2186
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002187Core language, builtins, and interpreter
2188
Guido van Rossum053ae352001-03-22 14:17:21 +00002189- The nested scopes work (enabled by "from __future__ import
2190 nested_scopes") is completed; in particular, the future now extends
2191 into code executed through exec, eval() and execfile(), and into the
2192 interactive interpreter.
2193
2194- When calling a base class method (e.g. BaseClass.__init__(self)),
2195 this is now allowed even if self is not strictly spoken a class
2196 instance (e.g. when using metaclasses or the Don Beaudry hook).
2197
2198- Slice objects are now comparable but not hashable; this prevents
2199 dict[:] from being accepted but meaningless.
2200
2201- Complex division is now calculated using less braindead algorithms.
2202 This doesn't change semantics except it's more likely to give useful
2203 results in extreme cases. Complex repr() now uses full precision
2204 like float repr().
2205
2206- sgmllib.py now calls handle_decl() for simple <!...> declarations.
2207
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002208- It is illegal to assign to the name __debug__, which is set when the
2209 interpreter starts. It is effectively a compile-time constant.
2210
2211- A warning will be issued if a global statement for a variable
2212 follows a use or assignment of that variable.
2213
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002214Standard library
2215
Guido van Rossum053ae352001-03-22 14:17:21 +00002216- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
2217 inspired by JUnit), is now part of the standard library. You now
2218 have a choice of two testing frameworks: unittest requires you to
2219 write testcases as separate code, doctest gathers them from
2220 docstrings. Both approaches have their advantages and
2221 disadvantages.
2222
2223- A new module Tix was added, which wraps the Tix extension library
2224 for Tk. With that module, it is not necessary to statically link
2225 Tix with _tkinter, since Tix will be loaded with Tcl's "package
2226 require" command. See Demo/tix/.
2227
2228- tzparse.py is now obsolete.
2229
2230- In gzip.py, the seek() and tell() methods are removed -- they were
2231 non-functional anyway, and it's better if callers can test for their
2232 existence with hasattr().
2233
2234Python/C API
2235
2236- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
2237 that's already in the dictionary during a PyDict_Next() iteration.
2238 This used to fail occasionally when a dictionary resize operation
2239 could be triggered that would rehash all the keys. All other
2240 modifications to the dictionary are still off-limits during a
2241 PyDict_Next() iteration!
2242
2243- New extended APIs related to passing compiler variables around.
2244
2245- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
2246 implement isinstance() and issubclass().
2247
2248- Py_BuildValue() now has a "D" conversion to create a Python complex
2249 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002250
Fred Drake4e262a92001-03-22 18:26:47 +00002251- Extensions types which support weak references must now set the
2252 field allocated for the weak reference machinery to NULL themselves;
2253 this is done to avoid the cost of checking each object for having a
2254 weakly referencable type in PyObject_INIT(), since most types are
2255 not weakly referencable.
2256
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002257- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
2258 free variables and cell variables to and from the frame's f_locals.
2259
2260- Variants of several functions defined in pythonrun.h have been added
2261 to support the nested_scopes future statement. The variants all end
2262 in Flags and take an extra argument, a PyCompilerFlags *; examples:
2263 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
2264 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00002265 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002266
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002267Distutils
2268
2269- the sdist command now writes a PKG-INFO file, as described in PEP 241,
2270 into the release tree.
2271
Tim Peters0e57abf2001-05-02 07:39:38 +00002272- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002273 (an uninstaller, more customization of the installer's display)
2274
2275- from Jack Jansen: added Mac-specific code to generate a dialog for
2276 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00002277 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002278 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00002279
2280- added 'platforms' and 'keywords' to the set of metadata that can be
2281 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002282
2283- applied patches from Jason Tishler to make the compiler class work with
2284 Cygwin.
2285
2286
Tim Peters2fe289a2001-03-01 22:19:38 +00002287What's New in Python 2.1 beta 1?
2288================================
Tim Petersd66595f2001-02-04 03:09:53 +00002289
2290Core language, builtins, and interpreter
2291
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00002292- Following an outcry from the community about the amount of code
2293 broken by the nested scopes feature introduced in 2.1a2, we decided
2294 to make this feature optional, and to wait until Python 2.2 (or at
2295 least 6 months) to make it standard. The option can be enabled on a
2296 per-module basis by adding "from __future__ import nested_scopes" at
2297 the beginning of a module (before any other statements, but after
2298 comments and an optional docstring). See PEP 236 (Back to the
2299 __future__) for a description of the __future__ statement. PEP 227
2300 (Statically Nested Scopes) has been updated to reflect this change,
2301 and to clarify the semantics in a number of endcases.
2302
2303- The nested scopes code, when enabled, has been hardened, and most
2304 bugs and memory leaks in it have been fixed.
2305
2306- Compile-time warnings are now generated for a number of conditions
2307 that will break or change in meaning when nested scopes are enabled:
2308
2309 - Using "from...import *" or "exec" without in-clause in a function
2310 scope that also defines a lambda or nested function with one or
2311 more free (non-local) variables. The presence of the import* or
2312 bare exec makes it impossible for the compiler to determine the
2313 exact set of local variables in the outer scope, which makes it
2314 impossible to determine the bindings for free variables in the
2315 inner scope. To avoid the warning about import *, change it into
2316 an import of explicitly name object, or move the import* statement
2317 to the global scope; to avoid the warning about bare exec, use
2318 exec...in... (a good idea anyway -- there's a possibility that
2319 bare exec will be deprecated in the future).
2320
2321 - Use of a global variable in a nested scope with the same name as a
2322 local variable in a surrounding scope. This will change in
2323 meaning with nested scopes: the name in the inner scope will
2324 reference the variable in the outer scope rather than the global
2325 of the same name. To avoid the warning, either rename the outer
2326 variable, or use a global statement in the inner function.
2327
Neil Schemenauera35c6882001-02-27 04:45:05 +00002328- An optional object allocator has been included. This allocator is
2329 optimized for Python objects and should be faster and use less memory
2330 than the standard system allocator. It is not enabled by default
2331 because of possible thread safety problems. The allocator is only
2332 protected by the Python interpreter lock and it is possible that some
2333 extension modules require a thread safe allocator. The object
2334 allocator can be enabled by providing the "--with-pymalloc" option to
2335 configure.
2336
Tim Petersd66595f2001-02-04 03:09:53 +00002337Standard library
2338
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002339- pyexpat now detects the expat version if expat.h defines it. A
2340 number of additional handlers are provided, which are only available
2341 since expat 1.95. In addition, the methods SetParamEntityParsing and
2342 GetInputContext of Parser objects are available with 1.95.x
2343 only. Parser objects now provide the ordered_attributes and
2344 specified_attributes attributes. A new module expat.model was added,
2345 which offers a number of additional constants if 1.95.x is used.
2346
2347- xml.dom offers the new functions registerDOMImplementation and
2348 getDOMImplementation.
2349
2350- xml.dom.minidom offers a toprettyxml method. A number of DOM
2351 conformance issues have been resolved. In particular, Element now
2352 has an hasAttributes method, and the handling of namespaces was
2353 improved.
2354
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002355- Ka-Ping Yee contributed two new modules: inspect.py, a module for
2356 getting information about live Python code, and pydoc.py, a module
2357 for interactively converting docstrings to HTML or text.
2358 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002359 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002360 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2361 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002362
Tim Peters1eff7962001-03-01 02:31:33 +00002363- New library module difflib.py, primarily packaging the SequenceMatcher
2364 class at the heart of the popular ndiff.py file-comparison tool.
2365
2366- doctest.py (a framework for verifying Python code examples in docstrings)
2367 is now part of the std library.
2368
Tim Petersd66595f2001-02-04 03:09:53 +00002369Windows changes
2370
Guido van Rossume3955a82001-03-02 14:05:59 +00002371- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2372 small GUI that lets you browse the module docstrings using your
2373 default web browser.
2374
Tim Peters1eff7962001-03-01 02:31:33 +00002375- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2376 Platforms) is implemented. See
2377
2378 http://python.sourceforge.net/peps/pep-0235.html
2379
2380 for full details, especially the "Current Lower-Left Semantics" section.
2381 The new Windows import rules are simpler than before:
2382
2383 A. If the PYTHONCASEOK environment variable exists, same as
2384 before: silently accept the first case-insensitive match of any
2385 kind; raise ImportError if none found.
2386
2387 B. Else search sys.path for the first case-sensitive match; raise
2388 ImportError if none found.
2389
2390 The same rules have been implented on other platforms with case-
2391 insensitive but case-preserving filesystems too (including Cygwin, and
2392 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002393
Tim Peters25a9ce32001-02-19 07:06:36 +00002394- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2395 what it's supposed to do (and does do under NT and 2000) via direct
2396 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002397 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002398 all Win9x systems before.
2399
Tim Peters1eff7962001-03-01 02:31:33 +00002400- Build: Subproject _test (effectively) renamed to _testcapi.
2401
Tim Peters2fe289a2001-03-01 22:19:38 +00002402New platforms
2403
2404- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2405 Thanks to Steven Majewski!
2406
2407- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2408 Tishler!
2409
Guido van Rossum9089b272001-03-02 06:49:50 +00002410- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2411 Schwertberger! See RISCOS/README for more information -- it seems
2412 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002413 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002414
Tim Peters25a9ce32001-02-19 07:06:36 +00002415
Tim Petersd7b5e882001-01-25 03:36:26 +00002416What's New in Python 2.1 alpha 2?
2417=================================
Tim Peters40ead762001-01-27 05:35:26 +00002418
Tim Petersd7b5e882001-01-25 03:36:26 +00002419Core language, builtins, and interpreter
2420
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002421- Scopes nest. If a name is used in a function or class, but is not
2422 local, the definition in the nearest enclosing function scope will
2423 be used. One consequence of this change is that lambda statements
2424 could reference variables in the namespaces where the lambda is
2425 defined. In some unusual cases, this change will break code.
2426
2427 In all previous version of Python, names were resolved in exactly
2428 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002429 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002430 function A is defined within a function B, the names bound in B are
2431 not visible in A. The new rules make names bound in B visible in A,
2432 unless A contains a name binding that hides the binding in B.
2433
2434 Section 4.1 of the reference manual describes the new scoping rules
2435 in detail. The test script in Lib/test/test_scope.py demonstrates
2436 some of the effects of the change.
2437
2438 The new rules will cause existing code to break if it defines nested
2439 functions where an outer function has local variables with the same
2440 name as globals or builtins used by the inner function. Example:
2441
2442 def munge(str):
2443 def helper(x):
2444 return str(x)
2445 if type(str) != type(''):
2446 str = helper(str)
2447 return str.strip()
2448
2449 Under the old rules, the name str in helper() is bound to the
2450 builtin function str(). Under the new rules, it will be bound to
2451 the argument named str and an error will occur when helper() is
2452 called.
2453
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002454- The compiler will report a SyntaxError if "from ... import *" occurs
2455 in a function or class scope. The language reference has documented
2456 that this case is illegal, but the compiler never checked for it.
2457 The recent introduction of nested scope makes the meaning of this
2458 form of name binding ambiguous. In a future release, the compiler
2459 may allow this form when there is no possibility of ambiguity.
2460
Tim Peters40ead762001-01-27 05:35:26 +00002461- repr(string) is easier to read, now using hex escapes instead of octal,
2462 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2463
2464 >>> "\texample \r\n" + chr(0) + chr(255)
2465 '\texample \r\n\x00\xff' # in 2.1
2466 '\011example \015\012\000\377' # in 2.0
2467
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002468- Functions are now compared and hashed by identity, not by value, since
2469 the func_code attribute is writable.
2470
Fred Drakefb9d7122001-02-01 20:00:40 +00002471- Weak references (PEP 205) have been added. This involves a few
2472 changes in the core, an extension module (_weakref), and a Python
2473 module (weakref). The weakref module is the public interface. It
2474 includes support for "explicit" weak references, proxy objects, and
2475 mappings with weakly held values.
2476
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002477- A 'continue' statement can now appear in a try block within the body
2478 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002479 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002480
Tim Petersd7b5e882001-01-25 03:36:26 +00002481Standard library
2482
Barry Warsaw30dbd142001-01-31 22:14:01 +00002483- mailbox.py now has a new class, PortableUnixMailbox which is
2484 identical to UnixMailbox but uses a more portable scheme for
2485 determining From_ separators. Also, the constructors for all the
2486 classes in this module have a new optional `factory' argument, which
2487 is a callable used when new message classes must be instantiated by
2488 the next() method.
2489
Tim Petersd7b5e882001-01-25 03:36:26 +00002490- random.py is now self-contained, and offers all the functionality of
2491 the now-deprecated whrandom.py. See the docs for details. random.py
2492 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002493 and restoring the internal state of the generator; and jumpahead(n),
2494 for quickly forcing the internal state to be the same as if n calls to
2495 random() had been made. The latter is particularly useful for multi-
2496 threaded programs, creating one instance of the random.Random() class for
2497 each thread, then using .jumpahead() to force each instance to use a
2498 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002499
Tim Peters0de88fc2001-02-01 04:59:18 +00002500- random.py's seed() function is new. For bit-for-bit compatibility with
2501 prior releases, use the whseed function instead. The new seed function
2502 addresses two problems: (1) The old function couldn't produce more than
2503 about 2**24 distinct internal states; the new one about 2**45 (the best
2504 that can be done in the Wichmann-Hill generator). (2) The old function
2505 sometimes produced identical internal states when passed distinct
2506 integers, and there was no simple way to predict when that would happen;
2507 the new one guarantees to produce distinct internal states for all
2508 arguments in [0, 27814431486576L).
2509
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002510- The socket module now supports raw packets on Linux. The socket
2511 family is AF_PACKET.
2512
Tim Peters9ea17ac2001-02-02 05:57:15 +00002513- test_capi.py is a start at running tests of the Python C API. The tests
2514 are implemented by the new Modules/_testmodule.c.
2515
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002516- A new extension module, _symtable, provides provisional access to the
2517 internal symbol table used by the Python compiler. A higher-level
2518 interface will be added on top of _symtable in a future release.
2519
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002520- Removed the obsolete soundex module.
2521
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002522- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2523 the isSameNode method; NamedNodeMap the get method.
2524
2525- xml.sax.expatreader supports the lexical handler property; it
2526 generates comment, startCDATA, and endCDATA events.
2527
Tim Petersee826f82001-01-31 19:39:44 +00002528Windows changes
2529
2530- Build procedure: the zlib project is built in a different way that
2531 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002532 the zlib binary used. See PCbuild\readme.txt for details. Your old
2533 zlib-related directories can be deleted; you'll need to download fresh
2534 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002535
Tim Peters9ea17ac2001-02-02 05:57:15 +00002536- Build: New subproject _test for the benefit of test_capi.py (see above).
2537
Tim Petersb16c56f2001-02-02 21:24:51 +00002538- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2539 interface to some Python compiler internals).
2540
2541- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002542 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002543
Tim Petersa3a3a032000-11-30 05:22:44 +00002544What's New in Python 2.1 alpha 1?
2545=================================
2546
2547Core language, builtins, and interpreter
2548
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002549- There is a new Unicode companion to the PyObject_Str() API
2550 called PyObject_Unicode(). It behaves in the same way as the
2551 former, but assures that the returned value is an Unicode object
2552 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002553
Guido van Rossumf98eda02001-01-17 15:54:45 +00002554- The comparison operators support "rich comparison overloading" (PEP
2555 207). C extension types can provide a rich comparison function in
2556 the new tp_richcompare slot in the type object. The cmp() function
2557 and the C function PyObject_Compare() first try the new rich
2558 comparison operators before trying the old 3-way comparison. There
2559 is also a new C API PyObject_RichCompare() (which also falls back on
2560 the old 3-way comparison, but does not constrain the outcome of the
2561 rich comparison to a Boolean result).
2562
2563 The rich comparison function takes two objects (at least one of
2564 which is guaranteed to have the type that provided the function) and
2565 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2566 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2567 object, which may be NotImplemented (in which case the tp_compare
2568 slot function is used as a fallback, if defined).
2569
2570 Classes can overload individual comparison operators by defining one
2571 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002572 __ge__. There are no explicit "reflected argument" versions of
2573 these; instead, __lt__ and __gt__ are each other's reflection,
2574 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2575 reflection (similar at the C level). No other implications are
2576 made; in particular, Python does not assume that == is the Boolean
2577 inverse of !=, or that < is the Boolean inverse of >=. This makes
2578 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002579
2580 Classes or types that want to implement (in)equality tests but not
2581 the ordering operators (i.e. unordered types) should implement ==
2582 and !=, and raise an error for the ordering operators.
2583
Guido van Rossuma88479f2001-01-18 14:28:08 +00002584 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002585 Boolean; e.g. a matrix type might want to return a matrix of bits
2586 for A < B, giving elementwise comparisons. Such types should ensure
2587 that any interpretation of their value in a Boolean context raises
2588 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2589 at the C level) to always raise an exception.
2590
Guido van Rossuma88479f2001-01-18 14:28:08 +00002591- Complex numbers use rich comparisons to define == and != but raise
2592 an exception for <, <=, > and >=. Unfortunately, this also means
2593 that cmp() of two complex numbers raises an exception when the two
2594 numbers differ. Since it is not mathematically meaningful to compare
2595 complex numbers except for equality, I hope that this doesn't break
2596 too much code.
2597
Tim Peters3389f192001-02-18 08:48:49 +00002598- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002599 not defined by the language, other than that it's arbitrary but
2600 consistent (see the Reference Manual). An implementation detail changed
2601 in 2.1a1 such that None now compares less than any other object. Code
2602 relying on this new behavior (like code that relied on the previous
2603 behavior) does so at its own risk.
2604
Barry Warsaw573b5412001-01-15 20:43:18 +00002605- Functions and methods now support getting and setting arbitrarily
2606 named attributes (PEP 232). Functions have a new __dict__
2607 (a.k.a. func_dict) which hold the function attributes. Methods get
2608 and set attributes on their underlying im_func. It is a TypeError
2609 to set an attribute on a bound method.
2610
Guido van Rossum051e3352001-01-15 19:11:10 +00002611- The xrange() object implementation has been improved so that
2612 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2613 limitation that in this case len(xrange(sys.maxint)) can't be
2614 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2615 work fine as long as the index i doesn't actually reach 2**31.
2616 (Python uses regular ints for sequence and string indices; fixing
2617 that is much more work.)
2618
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002619- Two changes to from...import:
2620
Guido van Rossumba381232001-02-03 15:06:40 +00002621 1) "from M import X" now works even if (after loading module M)
2622 sys.modules['M'] is not a real module; it's basically a getattr()
2623 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002624
2625 2) "from M import *" now looks for M.__all__ to decide which names to
2626 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2627 filters out names starting with '_' as before. Whether or not
2628 __all__ exists, there's no restriction on the type of M.
2629
Guido van Rossumf61f1662001-01-10 20:13:55 +00002630- File objects have a new method, xreadlines(). This is the fastest
2631 way to iterate over all lines in a file:
2632
2633 for line in file.xreadlines():
2634 ...do something to line...
2635
2636 See the xreadlines module (mentioned below) for how to do this for
2637 other file-like objects.
2638
2639- Even if you don't use file.xreadlines(), you may expect a speedup on
2640 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002641 quite a bit in platform-specific ways: on systems (like Linux) that
2642 support flockfile(), getc_unlocked(), and funlockfile(), those are
2643 used by default. On systems (like Windows) without getc_unlocked(),
2644 a complicated (but still thread-safe) method using fgets() is used by
2645 default.
2646
Tim Petersd52269b2001-01-25 06:23:18 +00002647 You can force use of the fgets() method by #define'ing
2648 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002649 getc_unlocked()).
2650
Tim Petersd52269b2001-01-25 06:23:18 +00002651 You can force fgets() not to be used by #define'ing
2652 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002653 test_bufio.py fails -- and let us know if it does!).
2654
2655- In addition, the fileinput module, while still slower than the other
2656 methods on most platforms, has been sped up too, by using
2657 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002658
2659- Support for run-time warnings has been added, including a new
2660 command line option (-W) to specify the disposition of warnings.
2661 See the description of the warnings module below.
2662
2663- Extensive changes have been made to the coercion code. This mostly
2664 affects extension modules (which can now implement mixed-type
2665 numerical operators without having to use coercion), but
2666 occasionally, in boundary cases the coercion semantics have changed
2667 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002668 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002669 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002670 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002671
Guido van Rossumf98eda02001-01-17 15:54:45 +00002672- In connection with the coercion changes, a new built-in singleton
2673 object, NotImplemented is defined. This can be returned for
2674 operations that wish to indicate they are not implemented for a
2675 particular combination of arguments. From C, this is
2676 Py_NotImplemented.
2677
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002678- The interpreter accepts now bytecode files on the command line even
2679 if they do not have a .pyc or .pyo extension. On Linux, after executing
2680
Martin v. Löwise214baa2001-02-04 22:37:56 +00002681import imp,sys,string
2682magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2683reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2684open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002685
2686 any byte code file can be used as an executable (i.e. as an argument
2687 to execve(2)).
2688
Tim Peters9940b802000-12-01 07:59:35 +00002689- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002690 character. In 1.6 and earlier, they never produced a sign,
2691 and raised an error if the value of the long was too large
2692 to fit in a Python int. In 2.0, they produced a sign if and
2693 only if too large to fit in an int. This was inconsistent
2694 across platforms (because the size of an int varies across
2695 platforms), and inconsistent with hex() and oct(). Example:
2696
2697 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002698 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002699 'ffffffbe' # in 2.0 and before, on 32-bit machines
2700 >>> hex(-0x42L)
2701 '-0x42L' # in all versions of Python
2702
Tim Peters9940b802000-12-01 07:59:35 +00002703 The behavior of %d formats for negative Python longs remains
2704 the same as in 2.0 (although in 1.6 and before, they raised
2705 an error if the long didn't fit in a Python int).
2706
2707 %u formats don't make sense for Python longs, but are allowed
2708 and treated the same as %d in 2.1. In 2.0, a negative long
2709 formatted via %u produced a sign if and only if too large to
2710 fit in an int. In 1.6 and earlier, a negative long formatted
2711 via %u raised an error if it was too big to fit in an int.
2712
Guido van Rossum3661d392000-12-12 22:10:31 +00002713- Dictionary objects have an odd new method, popitem(). This removes
2714 an arbitrary item from the dictionary and returns it (in the form of
2715 a (key, value) pair). This can be useful for algorithms that use a
2716 dictionary as a bag of "to do" items and repeatedly need to pick one
2717 item. Such algorithms normally end up running in quadratic time;
2718 using popitem() they can usually be made to run in linear time.
2719
Tim Peters36cdad12000-12-29 02:06:45 +00002720Standard library
2721
Thomas Woutersfe385252001-01-19 23:16:56 +00002722- In the time module, the time argument to the functions strftime,
2723 localtime, gmtime, asctime and ctime is now optional, defaulting to
2724 the current time (in the local timezone).
2725
Guido van Rossumda91f222001-01-15 16:36:08 +00002726- The ftplib module now defaults to passive mode, which is deemed a
2727 more useful default given that clients are often inside firewalls
2728 these days. Note that this could break if ftplib is used to connect
2729 to a *server* that is inside a firewall, from outside; this is
2730 expected to be a very rare situation. To fix that, you can call
2731 ftp.set_pasv(0).
2732
Martin v. Löwis10a27872001-01-13 09:54:41 +00002733- The module site now treats .pth files not only for path configuration,
2734 but also supports extensions to the initialization code: Lines starting
2735 with import are executed.
2736
Guido van Rossumf61f1662001-01-10 20:13:55 +00002737- There's a new module, warnings, which implements a mechanism for
2738 issuing and filtering warnings. There are some new built-in
2739 exceptions that serve as warning categories, and a new command line
2740 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2741 turns warnings into errors). warnings.warn(message[, category])
2742 issues a warning message; this can also be called from C as
2743 PyErr_Warn(category, message).
2744
2745- A new module xreadlines was added. This exports a single factory
2746 function, xreadlines(). The intention is that this code is the
2747 absolutely fastest way to iterate over all lines in an open
2748 file(-like) object:
2749
2750 import xreadlines
2751 for line in xreadlines.xreadlines(file):
2752 ...do something to line...
2753
2754 This is equivalent to the previous the speed record holder using
2755 file.readlines(sizehint). Note that if file is a real file object
2756 (as opposed to a file-like object), this is equivalent:
2757
2758 for line in file.xreadlines():
2759 ...do something to line...
2760
Tim Peters36cdad12000-12-29 02:06:45 +00002761- The bisect module has new functions bisect_left, insort_left,
2762 bisect_right and insort_right. The old names bisect and insort
2763 are now aliases for bisect_right and insort_right. XXX_right
2764 and XXX_left methods differ in what happens when the new element
2765 compares equal to one or more elements already in the list: the
2766 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002767 right. Code that doesn't care where equal elements end up should
2768 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002769
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002770- The new curses.panel module wraps the panel library that forms part
2771 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2772
Guido van Rossumf61f1662001-01-10 20:13:55 +00002773- The SocketServer module now sets the allow_reuse_address flag by
2774 default in the TCPServer class.
2775
2776- A new function, sys._getframe(), returns the stack frame pointer of
2777 the caller. This is intended only as a building block for
2778 higher-level mechanisms such as string interpolation.
2779
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002780- The pyexpat module supports a number of new handlers, which are
2781 available only in expat 1.2. If invocation of a callback fails, it
2782 will report an additional frame in the traceback. Parser objects
2783 participate now in garbage collection. If expat reports an unknown
2784 encoding, pyexpat will try to use a Python codec; that works only
2785 for single-byte charsets. The parser type objects is exposed as
2786 XMLParserObject.
2787
2788- xml.dom now offers standard definitions for symbolic node type and
2789 exception code constants, and a hierarchy of DOM exceptions. minidom
2790 was adjusted to use them.
2791
2792- The conformance of xml.dom.minidom to the DOM specification was
2793 improved. It detects a number of additional error cases; the
2794 previous/next relationship works even when the tree is modified;
2795 Node supports the normalize() method; NamedNodeMap, DocumentType and
2796 DOMImplementation classes were added; Element supports the
2797 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2798 method.
2799
Guido van Rossumf61f1662001-01-10 20:13:55 +00002800Build issues
2801
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002802- For Unix (and Unix-compatible) builds, configuration and building of
2803 extension modules is now greatly automated. Rather than having to
2804 edit the Modules/Setup file to indicate which modules should be
2805 built and where their include files and libraries are, a
2806 distutils-based setup.py script now takes care of building most
2807 extension modules. All extension modules built this way are built
2808 as shared libraries. Only a few modules that must be linked
2809 statically are still listed in the Setup file; you won't need to
2810 edit their configuration.
2811
2812- Python should now build out of the box on Cygwin. If it doesn't,
2813 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002814
2815- Python now always uses its own (renamed) implementation of getopt()
2816 -- there's too much variation among C library getopt()
2817 implementations.
2818
2819- C++ compilers are better supported; the CXX macro is always set to a
2820 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002821
Tim Petersd92dfe02000-12-12 01:18:41 +00002822Windows changes
2823
2824- select module: By default under Windows, a select() call
2825 can specify no more than 64 sockets. Python now boosts
2826 this Microsoft default to 512. If you need even more than
2827 that, see the MS docs (you'll need to #define FD_SETSIZE
2828 and recompile Python from source).
2829
Guido van Rossumf61f1662001-01-10 20:13:55 +00002830- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2831 subdirectory is no more!
2832
Tim Petersa3a3a032000-11-30 05:22:44 +00002833
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002834What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002835=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002836
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002837Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002838changes are in the file HISTORY. If you are making the jump directly
2839from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2840HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002841
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002842Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2843the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2844http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002845
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002846--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002847
2848======================================================================
2849
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002850What's new in 2.0 (since release candidate 1)?
2851==============================================
2852
2853Standard library
2854
2855- The copy_reg module was modified to clarify its intended use: to
2856 register pickle support for extension types, not for classes.
2857 pickle() will raise a TypeError if it is passed a class.
2858
2859- Fixed a bug in gettext's "normalize and expand" code that prevented
2860 it from finding an existing .mo file.
2861
2862- Restored support for HTTP/0.9 servers in httplib.
2863
Tim Peters989b7b92000-10-16 20:24:53 +00002864- The math module was changed to stop raising OverflowError in case of
2865 underflow, and return 0 instead in underflow cases. Whether Python
2866 used to raise OverflowError in case of underflow was platform-
2867 dependent (it did when the platform math library set errno to ERANGE
2868 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002869
2870- Fixed a bug in StringIO that occurred when the file position was not
2871 at the end of the file and write() was called with enough data to
2872 extend past the end of the file.
2873
2874- Fixed a bug that caused Tkinter error messages to get lost on
2875 Windows. The bug was fixed by replacing direct use of
2876 interp->result with Tcl_GetStringResult(interp).
2877
2878- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2879 redirect response.
2880
2881- Several changes were made to distutils: Some debugging code was
2882 removed from util. Fixed the installer used when an external zip
2883 program (like WinZip) is not found; the source code for this
2884 installer is in Misc/distutils. check_lib() was modified to behave
2885 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2886 test for whether installed modules are on sys.path was changed to
2887 use both normcase() and normpath().
2888
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002889- Several minor bugs were fixed in the xml package (the minidom,
2890 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002891
2892- The regression test driver (regrtest.py) behavior when invoked with
2893 -l changed: It now reports a count of objects that are recognized as
2894 garbage but not freed by the garbage collector.
2895
Tim Peters989b7b92000-10-16 20:24:53 +00002896- The regression test for the math module was changed to test
2897 exceptional behavior when the test is run in verbose mode. Python
2898 cannot yet guarantee consistent exception behavior across platforms,
2899 so the exception part of test_math is run only in verbose mode, and
2900 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002901
2902Internals
2903
2904- PyOS_CheckStack() has been disabled on Win64, where it caused
2905 test_sre to fail.
2906
2907Build issues
2908
2909- Changed compiler flags, so that gcc is always invoked with -Wall and
2910 -Wstrict-prototypes. Users compiling Python with GCC should see
2911 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002912 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002913 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002914
Tim Petersa3a3a032000-11-30 05:22:44 +00002915- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002916
2917Tools and other miscellany
2918
2919- The compiler in Tools/compiler was updated to support the new
2920 language features introduced in 2.0: extended print statement, list
2921 comprehensions, and augmented assignments. The new compiler should
2922 also be backwards compatible with Python 1.5.2; the compiler will
2923 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002924 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002925
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002926What's new in 2.0 release candidate 1 (since beta 2)?
2927=====================================================
2928
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002929What is release candidate 1?
2930
2931We believe that release candidate 1 will fix all known bugs that we
2932intend to fix for the 2.0 final release. This release should be a bit
2933more stable than the previous betas. We would like to see even more
2934widespread testing before the final release, so we are producing this
2935release candidate. The final release will be exactly the same unless
2936any show-stopping (or brown bag) bugs are found by testers of the
2937release candidate.
2938
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002939All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002940to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002941
2942Core language, builtins, and interpreter
2943
2944- A bug that caused crashes when __coerce__ was used with augmented
2945 assignment, e.g. +=, was fixed.
2946
2947- Raise ZeroDivisionError when raising zero to a negative number,
2948 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2949 power operator and the result of math.pow(0.0, -2.0) will vary by
2950 platform. On Linux, it raises a ValueError.
2951
2952- A bug in Unicode string interpolation was fixed that occasionally
2953 caused errors with formats including "%%". For example, the
2954 following expression "%% %s" % u"abc" no longer raises a TypeError.
2955
2956- Compilation of deeply nested expressions raises MemoryError instead
2957 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2958
2959- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2960 rendering them useless. They are now written in binary mode again.
2961
2962Standard library
2963
2964- Keyword arguments are now accepted for most pattern and match object
2965 methods in SRE, the standard regular expression engine.
2966
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002967- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002968 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002969
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002970- Several bugs in the Unicode handling and error handling in _tkinter
2971 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002972
2973- Fix memory management errors in Merge() and Tkapp_Call() routines.
2974
2975- Several changes were made to cStringIO to make it compatible with
2976 the file-like object interface and with StringIO. If operations are
2977 performed on a closed object, an exception is raised. The truncate
2978 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002979 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002980
2981- There were many changes made to the linuxaudiodev module and its
2982 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002983 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002984
2985 Note that this module is named poorly, because it should work
2986 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002987 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002988
2989 The module now raises exceptions when errors occur instead of
2990 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2991 audio) and defines a getptr() method that calls the
2992 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2993
2994- The library_version attribute, introduced in an earlier beta, was
2995 removed because it can not be supported with early versions of the C
2996 readline library, which provides no way to determine the version at
2997 compile-time.
2998
2999- The binascii module is now enabled on Win64.
3000
Tim Peters46446d62000-10-09 21:19:31 +00003001- tokenize.py no longer suffers "recursion depth" errors when parsing
3002 programs with very long string literals.
3003
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003004Internals
3005
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003006- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003007 which is called when the interpreter starts up to determine where
3008 the standard library is installed. These vulnerabilities affect all
3009 previous versions of Python and can be exploited by setting very
3010 long values for PYTHONHOME or argv[0]. The risk is greatest for a
3011 setuid Python script, although use of the wrapper in
3012 Misc/setuid-prog.c will eliminate the vulnerability.
3013
3014- Fixed garbage collection bugs in instance creation that were
3015 triggered when errors occurred during initialization. The solution,
3016 applied in cPickle and in PyInstance_New(), is to call
3017 PyObject_GC_Init() after the initialization of the object's
3018 container attributes is complete.
3019
3020- pyexpat adds definitions of PyModule_AddStringConstant and
3021 PyModule_AddObject if the Python version is less than 2.0, which
3022 provides compatibility with PyXML on Python 1.5.2.
3023
3024- If the platform has a bogus definition for LONG_BIT (the number of
3025 bits in a long), an error will be reported at compile time.
3026
3027- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
3028 collection crashes and possibly other, unreported crashes.
3029
3030- Fixed a memory leak in _PyUnicode_Fini().
3031
3032Build issues
3033
3034- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003035 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00003036 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003037
3038- The mmap.PAGESIZE constant is now initialized using sysconf when
3039 possible, which eliminates a dependency on -lucb for Reliant UNIX.
3040
3041- The md5 file should now compile on all platforms.
3042
3043- The select module now compiles on platforms that do not define
3044 POLLRDNORM and related constants.
3045
3046- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00003047 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003048
Jeremy Hylton10921202000-10-09 18:34:12 +00003049- BeOS: A number of changes were made to the build and installation
3050 process. ar-fake now operates on a directory of object files.
3051 dl_export.h is gone, and its macros now appear on the mwcc command
3052 line during build on PPC BeOS.
3053
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003054- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00003055 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003056
3057- Cygwin: Support for shared libraries, Tkinter, and sockets.
3058
3059- SunOS 4.1.4_JL: Fix test for directory existence in configure.
3060
3061Tools and other miscellany
3062
3063- Removed debugging prints from main used with freeze.
3064
Tim Peters46446d62000-10-09 21:19:31 +00003065- IDLE auto-indent no longer crashes when it encounters Unicode
3066 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003067
3068What's new in 2.0 beta 2 (since beta 1)?
3069========================================
3070
3071Core language, builtins, and interpreter
3072
Tim Peters482c0212000-09-26 06:33:09 +00003073- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003074 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003075
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003076- Add -h and -V command line options to print the usage message and
3077 Python version number and exit immediately.
3078
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003079- eval() and exec accept Unicode objects as code parameters.
3080
3081- getattr() and setattr() now also accept Unicode objects for the
3082 attribute name, which are converted to strings using the default
3083 encoding before lookup.
3084
3085- Multiplication on string and Unicode now does proper bounds
3086 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
3087 string is too long."
3088
3089- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00003090 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003091
Jeremy Hylton1b618592000-09-26 05:32:36 +00003092
3093Standard library and extensions
3094
Guido van Rossum5b08f132001-04-16 02:05:23 +00003095- socket module: the OpenSSL code now adds support for RAND_status()
3096 and EGD (Entropy Gathering Device).
3097
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003098- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00003099 argument checking; it still takes no arguments.
3100
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003101- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003102
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003103- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003104
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003105- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003106
3107- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003108 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003109
3110- copy: Copy Unicode objects atomically.
3111
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003112- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003113
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003114- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003115
Fred Drake67233bc2000-09-26 16:40:27 +00003116- dbm: Add get() and setdefault() methods to dbm object. Add constant
3117 `library' to module that names the library used. Added doc strings
3118 and method names to error messages. Uses configure to determine
3119 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
3120 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003121
3122- distutils: Update to version 0.9.3.
3123
3124- dl: Add several dl.RTLD_ constants.
3125
3126- fpectl: Now supported on FreeBSD.
3127
3128- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
3129 found by the collector will be saved in gc.garbage. This is useful
3130 for debugging a program that creates reference cycles.
3131
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003132- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00003133 of HTTP class. Do not close socket on zero-length response. Do not
3134 crash when server sends invalid content-length header.
3135
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003136- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003137
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003138- marshal: When reading a short, sign-extend on platforms where shorts
3139 are bigger than 16 bits. When reading a long, repair the unportable
3140 sign extension that was being done for 64-bit machines. (It assumed
3141 that signed right shift sign-extends.)
3142
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003143- operator: Add contains(), invert(), __invert__() as aliases for
3144 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003145
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003146- os: Add support for popen2() and popen3() on all platforms where
3147 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003148
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003149- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00003150 clicking on a file in Explorer (or passing the file name to the
3151 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003152
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003153- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00003154 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003155
3156- pickle: Now raises ValueError when an invalid pickle that contains
3157 a non-string repr where a string repr was expected. This behavior
3158 matches cPickle.
3159
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003160- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003161
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003162- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003163
3164- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003165 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003166 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003167
3168- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003169 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003170
3171- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00003172 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00003173 few cycles during startup since the first call to
3174 setdefaultencoding() will initialize the codec registry and the
3175 encodings package.
3176
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003177- socket: Support for size hint in readlines() method of object returned
3178 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003179
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003180- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00003181 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00003182 is followed by whitespace.
3183
Tim Petersa3a3a032000-11-30 05:22:44 +00003184- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003185
3186- struct: Check ranges for bytes and shorts.
3187
3188- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003189 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003190
3191- Tkinter: Image objects are now guaranteed to have unique ids. Set
3192 event.delta to zero if Tk version doesn't support mousewheel.
3193 Removed some debugging prints.
3194
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003195- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003196
Fred Drake67233bc2000-09-26 16:40:27 +00003197- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003198 which works around a bug in Norton AntiVirus 2000 that leads directly
3199 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003200
3201- xml: New version detection code allows PyXML to override standard
3202 XML package if PyXML version is greater than 0.6.1.
3203
Fred Drake64bb3802000-09-26 16:21:35 +00003204- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
3205 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
3206 tree only for nodes which are sufficiently interesting to a specific
3207 application. Does not provide the HTML-specific extensions. Still
3208 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003209
Fred Drake64bb3802000-09-26 16:21:35 +00003210- xml.sax: SAX 2 support for Python, including all the handler
3211 interfaces needed to process XML 1.0 compliant XML. Some
3212 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003213
Fred Drake64bb3802000-09-26 16:21:35 +00003214- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
3215 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003216
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003217
Jeremy Hylton1b618592000-09-26 05:32:36 +00003218C API
3219
3220- Add three new convenience functions for module initialization --
3221 PyModule_AddObject(), PyModule_AddIntConstant(), and
3222 PyModule_AddStringConstant().
3223
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003224- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00003225 removed and add #error to Python.h if NULL isn't defined after
3226 #include of stdio.h.
3227
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003228- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00003229 backwards compatibility (at the source level) with old extensions.
3230
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003231- A wrapper API was added for signal() and sigaction(). Instead of
3232 either function, always use PyOS_getsig() to get a signal handler
3233 and PyOS_setsig() to set one. A new convenience typedef
3234 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003235
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003236- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00003237 internal data buffer and size of a string object -- or the default
3238 encoded version of a Unicode object.
3239
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003240- PyString_Size() and PyString_AsString() accept Unicode objects.
3241
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003242- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00003243 exists). INT_MAX and LONG_MAX will always be defined, even if
3244 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003245
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003246- PyFloat_FromString takes a second argument, pend, that was
3247 effectively useless. It is now officially useless but preserved for
3248 backwards compatibility. If the pend argument is not NULL, *pend is
3249 set to NULL.
3250
3251- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
3252 for the attribute name. See note on getattr() above.
3253
3254- A few bug fixes to argument processing for Unicode.
3255 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
3256 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
3257 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00003258 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003259
3260- Py_BuildValue accepts B format (for bgen-generated code).
3261
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003262
Jeremy Hylton1b618592000-09-26 05:32:36 +00003263Internals
3264
3265- On Unix, fix code for finding Python installation directory so that
3266 it works when argv[0] is a relative path.
3267
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00003268- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003269 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00003270 rather than by generating a copy of the object.
3271
Tim Peters482c0212000-09-26 06:33:09 +00003272- Several of the internal Unicode tables are much smaller now, and
3273 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003274
Jeremy Hylton97693b02000-09-26 17:42:51 +00003275- In the garbage collector: Fixed bug in collection of tuples. Fixed
3276 bug that caused some instances to be removed from the container set
3277 while they were still live. Fixed parsing in gc.set_debug() for
3278 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003279
3280- Fixed refcount problem in instance deallocation that only occurred
3281 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
3282
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003283- On Windows, getpythonregpath is now protected against null data in
3284 registry key.
3285
3286- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00003287 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003288
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003289
Jeremy Hylton1b618592000-09-26 05:32:36 +00003290Build and platform-specific issues
3291
3292- Better support of GNU Pth via --with-pth configure option.
3293
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003294- Python/C API now properly exposed to dynamically-loaded extension
3295 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003296
3297- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
3298 Don't define MS_SYNC to be zero when it is undefined. Added missing
3299 prototypes in posixmodule.c.
3300
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003301- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003302 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003303
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003304- Fix largefile support on older NetBSD systems and OpenBSD by adding
3305 define for TELL64.
3306
3307
3308Tools and other miscellany
3309
3310- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
3311
3312- freeze: The modulefinder now works with 2.0 opcodes.
3313
Tim Petersa3a3a032000-11-30 05:22:44 +00003314- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003315 Move hackery of sys.argv until after the Tk instance has been
3316 created, which allows the application-specific Tkinter
3317 initialization to be executed if present; also pass an explicit
3318 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00003319
Jeremy Hylton1b618592000-09-26 05:32:36 +00003320
3321What's new in 2.0 beta 1?
3322=========================
3323
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003324Source Incompatibilities
3325------------------------
3326
3327None. Note that 1.6 introduced several incompatibilities with 1.5.2,
3328such as single-argument append(), connect() and bind(), and changes to
3329str(long) and repr(float).
3330
3331
3332Binary Incompatibilities
3333------------------------
3334
3335- Third party extensions built for Python 1.5.x or 1.6 cannot be used
3336with Python 2.0; these extensions will have to be rebuilt for Python
33372.0.
3338
3339- On Windows, attempting to import a third party extension built for
3340Python 1.5.x or 1.6 results in an immediate crash; there's not much we
3341can do about this. Check your PYTHONPATH environment variable!
3342
3343- Python bytecode files (*.pyc and *.pyo) are not compatible between
3344releases.
3345
3346
3347Overview of Changes Since 1.6
3348-----------------------------
3349
3350There are many new modules (including brand new XML support through
3351the xml package, and i18n support through the gettext module); a list
3352of all new modules is included below. Lots of bugs have been fixed.
3353
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003354The process for making major new changes to the language has changed
3355since Python 1.6. Enhancements must now be documented by a Python
3356Enhancement Proposal (PEP) before they can be accepted.
3357
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003358There are several important syntax enhancements, described in more
3359detail below:
3360
3361 - Augmented assignment, e.g. x += 1
3362
3363 - List comprehensions, e.g. [x**2 for x in range(10)]
3364
3365 - Extended import statement, e.g. import Module as Name
3366
3367 - Extended print statement, e.g. print >> file, "Hello"
3368
3369Other important changes:
3370
3371 - Optional collection of cyclical garbage
3372
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003373Python Enhancement Proposal (PEP)
3374---------------------------------
3375
3376PEP stands for Python Enhancement Proposal. A PEP is a design
3377document providing information to the Python community, or describing
3378a new feature for Python. The PEP should provide a concise technical
3379specification of the feature and a rationale for the feature.
3380
3381We intend PEPs to be the primary mechanisms for proposing new
3382features, for collecting community input on an issue, and for
3383documenting the design decisions that have gone into Python. The PEP
3384author is responsible for building consensus within the community and
3385documenting dissenting opinions.
3386
3387The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003388
3389Augmented Assignment
3390--------------------
3391
3392This must have been the most-requested feature of the past years!
3393Eleven new assignment operators were added:
3394
Guido van Rossume905e952000-09-05 12:42:46 +00003395 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003396
3397For example,
3398
3399 A += B
3400
3401is similar to
3402
3403 A = A + B
3404
3405except that A is evaluated only once (relevant when A is something
3406like dict[index].attr).
3407
3408However, if A is a mutable object, A may be modified in place. Thus,
3409if A is a number or a string, A += B has the same effect as A = A+B
3410(except A is only evaluated once); but if a is a list, A += B has the
3411same effect as A.extend(B)!
3412
3413Classes and built-in object types can override the new operators in
3414order to implement the in-place behavior; the not-in-place behavior is
3415used automatically as a fallback when an object doesn't implement the
3416in-place behavior. For classes, the method name is derived from the
3417method name for the corresponding not-in-place operator by inserting
3418an 'i' in front of the name, e.g. __iadd__ implements in-place
3419__add__.
3420
3421Augmented assignment was implemented by Thomas Wouters.
3422
3423
3424List Comprehensions
3425-------------------
3426
3427This is a flexible new notation for lists whose elements are computed
3428from another list (or lists). The simplest form is:
3429
3430 [<expression> for <variable> in <sequence>]
3431
Guido van Rossum56db0952000-09-06 23:34:25 +00003432For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003433This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003434
3435You can also add a condition:
3436
3437 [<expression> for <variable> in <sequence> if <condition>]
3438
3439For example, [w for w in words if w == w.lower()] would yield the list
3440of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003441than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003442
3443You can also have nested for loops and more than one 'if' clause. For
3444example, here's a function that flattens a sequence of sequences::
3445
3446 def flatten(seq):
3447 return [x for subseq in seq for x in subseq]
3448
3449 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3450
3451This prints
3452
3453 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3454
3455List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003456Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003457
3458
3459Extended Import Statement
3460-------------------------
3461
3462Many people have asked for a way to import a module under a different
3463name. This can be accomplished like this:
3464
3465 import foo
3466 bar = foo
3467 del foo
3468
3469but this common idiom gets old quickly. A simple extension of the
3470import statement now allows this to be written as follows:
3471
3472 import foo as bar
3473
3474There's also a variant for 'from ... import':
3475
3476 from foo import bar as spam
3477
3478This also works with packages; e.g. you can write this:
3479
3480 import test.regrtest as regrtest
3481
3482Note that 'as' is not a new keyword -- it is recognized only in this
3483context (this is only possible because the syntax for the import
3484statement doesn't involve expressions).
3485
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003486Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003487
3488
3489Extended Print Statement
3490------------------------
3491
3492Easily the most controversial new feature, this extension to the print
3493statement adds an option to make the output go to a different file
3494than the default sys.stdout.
3495
3496For example, to write an error message to sys.stderr, you can now
3497write:
3498
3499 print >> sys.stderr, "Error: bad dog!"
3500
3501As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003502evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003503
3504 print >> None, "Hello world"
3505
3506is equivalent to
3507
3508 print "Hello world"
3509
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003510Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003511
3512
3513Optional Collection of Cyclical Garbage
3514---------------------------------------
3515
3516Python is now equipped with a garbage collector that can hunt down
3517cyclical references between Python objects. It's no replacement for
3518reference counting; in fact, it depends on the reference counts being
3519correct, and decides that a set of objects belong to a cycle if all
3520their reference counts can be accounted for from their references to
3521each other. This devious scheme was first proposed by Eric Tiedemann,
3522and brought to implementation by Neil Schemenauer.
3523
3524There's a module "gc" that lets you control some parameters of the
3525garbage collection. There's also an option to the configure script
3526that lets you enable or disable the garbage collection. In 2.0b1,
3527it's on by default, so that we (hopefully) can collect decent user
3528experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003529performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003530off by default in the final 2.0 release.
3531
3532
3533Smaller Changes
3534---------------
3535
3536A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3537map(None, seq1, seq2, ...) when the sequences have the same length;
3538i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3539the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003540zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003541
3542sys.version_info is a tuple (major, minor, micro, level, serial).
3543
3544Dictionaries have an odd new method, setdefault(key, default).
3545dict.setdefault(key, default) returns dict[key] if it exists; if not,
3546it sets dict[key] to default and returns that value. Thus:
3547
3548 dict.setdefault(key, []).append(item)
3549
3550does the same work as this common idiom:
3551
3552 if not dict.has_key(key):
3553 dict[key] = []
3554 dict[key].append(item)
3555
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003556There are two new variants of SyntaxError that are raised for
3557indentation-related errors: IndentationError and TabError.
3558
3559Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3560escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003561
3562The limits on the size of expressions and file in Python source code
3563have been raised from 2**16 to 2**32. Previous versions of Python
3564were limited because the maximum argument size the Python VM accepted
3565was 2**16. This limited the size of object constructor expressions,
3566e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3567limit was raised thanks to a patch by Charles Waldman that effectively
3568fixes the problem. It is now much more likely that you will be
3569limited by available memory than by an arbitrary limit in Python.
3570
3571The interpreter's maximum recursion depth can be modified by Python
3572programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3573limit is the maximum number of recursive calls that can be made by
3574Python code. The limit exists to prevent infinite recursion from
3575overflowing the C stack and causing a core dump. The default value is
35761000. The maximum safe value for a particular platform can be found
3577by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003578
3579New Modules and Packages
3580------------------------
3581
3582atexit - for registering functions to be called when Python exits.
3583
3584imputil - Greg Stein's alternative API for writing custom import
3585hooks.
3586
3587pyexpat - an interface to the Expat XML parser, contributed by Paul
3588Prescod.
3589
3590xml - a new package with XML support code organized (so far) in three
3591subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3592would fill a volume. There's a special feature whereby a
3593user-installed package named _xmlplus overrides the standard
3594xmlpackage; this is intended to give the XML SIG a hook to distribute
3595backwards-compatible updates to the standard xml package.
3596
3597webbrowser - a platform-independent API to launch a web browser.
3598
3599
Guido van Rossume905e952000-09-05 12:42:46 +00003600Changed Modules
3601---------------
3602
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003603array -- new methods for array objects: count, extend, index, pop, and
3604remove
3605
3606binascii -- new functions b2a_hex and a2b_hex that convert between
3607binary data and its hex representation
3608
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003609calendar -- Many new functions that support features including control
3610over which day of the week is the first day, returning strings instead
3611of printing them. Also new symbolic constants for days of week,
3612e.g. MONDAY, ..., SUNDAY.
3613
3614cgi -- FieldStorage objects have a getvalue method that works like a
3615dictionary's get method and returns the value attribute of the object.
3616
3617ConfigParser -- The parser object has new methods has_option,
3618remove_section, remove_option, set, and write. They allow the module
3619to be used for writing config files as well as reading them.
3620
3621ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003622optionally support the RFC 959 REST command.
3623
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003624gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003625
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003626httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3627the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003628
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003629locale -- implement getdefaultlocale for Win32 and Macintosh
3630
3631marshal -- no longer dumps core when marshaling deeply nested or
3632recursive data structures
3633
3634os -- new functions isatty, seteuid, setegid, setreuid, setregid
3635
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003636os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3637support under Unix.
3638
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003639os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003640
3641os.path -- fix semantics of os.path.commonprefix
3642
3643smtplib -- support for sending very long messages
3644
3645socket -- new function getfqdn()
3646
3647readline -- new functions to read, write and truncate history files.
3648The readline section of the library reference manual contains an
3649example.
3650
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003651select -- add interface to poll system call
3652
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003653shutil -- new copyfileobj function
3654
3655SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3656HTTP server.
3657
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003658Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003659
3660urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003661e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003662
3663whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003664
3665
3666Obsolete Modules
3667----------------
3668
3669None. However note that 1.6 made a whole slew of modules obsolete:
3670stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3671poly, zmod, strop, util, whatsound.
3672
3673
3674Changed, New, Obsolete Tools
3675----------------------------
3676
Tim Peters8b092332000-09-05 20:15:25 +00003677None.
Guido van Rossume905e952000-09-05 12:42:46 +00003678
3679
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003680C-level Changes
3681---------------
3682
3683Several cleanup jobs were carried out throughout the source code.
3684
3685All C code was converted to ANSI C; we got rid of all uses of the
3686Py_PROTO() macro, which makes the header files a lot more readable.
3687
3688Most of the portability hacks were moved to a new header file,
3689pyport.h; several other new header files were added and some old
3690header files were removed, in an attempt to create a more rational set
3691of header files. (Few of these ever need to be included explicitly;
3692they are all included by Python.h.)
3693
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003694Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003695and Win64, especially for the new Intel Itanium processor. Mick also
3696added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003697
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003698The C APIs to return an object's size have been update to consistently
3699use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3700previous versions, the abstract interfaces used PyXXX_Length and the
3701concrete interfaces used PyXXX_Size. The old names,
3702e.g. PyObject_Length, are still available for backwards compatibility
3703at the API level, but are deprecated.
3704
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003705The PyOS_CheckStack function has been implemented on Windows by
3706Fredrik Lundh. It prevents Python from failing with a stack overflow
3707on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003708
3709The GC changes resulted in creation of two new slots on object,
3710tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003711the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003712
3713The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003714C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003715
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003716PyErr_Format has been updated to automatically calculate the size of
3717the buffer needed to hold the formatted result string. This change
3718prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003719
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003720New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003721
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003722PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3723that are the same as their non-Ex counterparts except they take an
3724extra flag argument that tells them to close the file when done.
3725
3726XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003727
Tim Peters8b092332000-09-05 20:15:25 +00003728
3729Windows Changes
3730---------------
3731
3732New popen2/popen3/peopen4 in os module (see Changed Modules above).
3733
3734os.popen is much more usable on Windows 95 and 98. See Microsoft
3735Knowledge Base article Q150956. The Win9x workaround described there
3736is implemented by the new w9xpopen.exe helper in the root of your
3737Python installation. Note that Python uses this internally; it is not
3738a standalone program.
3739
3740Administrator privileges are no longer required to install Python
3741on Windows NT or Windows 2000. If you have administrator privileges,
3742Python's registry info will be written under HKEY_LOCAL_MACHINE.
3743Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003744under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003745uses of Python, but will prevent some advanced uses from working
3746(for example, running a Python script as an NT service, or possibly
3747from CGI).
3748
3749[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3750installer; instead, it installs the needed Tcl/Tk files directly in the
3751Python directory. If you already have a Tcl/Tk installation, this
3752wastes some disk space (about 4 Megs) but avoids problems with
3753conflicting Tcl/Tk installations, and makes it much easier for Python
3754to ensure that Tcl/Tk can find all its files.
3755
3756[This was new in 1.6] The Windows installer now installs by default in
3757\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3758
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003759
3760Updates to the changes between 1.5.2 and 1.6
3761--------------------------------------------
3762
3763The 1.6 NEWS file can't be changed after the release is done, so here
3764is some late-breaking news:
3765
3766New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3767and changes to getlocale() and setlocale().
3768
3769The new module is now enabled per default.
3770
3771It is not true that the encodings codecs cannot be used for normal
3772strings: the string.encode() (which is also present on 8-bit strings
3773!) allows using them for 8-bit strings too, e.g. to convert files from
3774cp1252 (Windows) to latin-1 or vice-versa.
3775
3776Japanese codecs are available from Tamito KAJIYAMA:
3777http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3778
3779
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003780======================================================================