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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
Neal Norwitz649b7592002-01-01 19:07:13 +0000236- file.xreadlines() now raises a ValueError if the file is closed:
237 Previously, an xreadlines object was returned which would raise
238 a ValueError when the xreadlines.next() method was called.
239
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000240- sys.exit() inadvertently allowed more than one argument.
Neal Norwitz0c766a02002-03-27 13:03:09 +0000241 An exception will now be raised if more than one argument is used.
242
Tim Petersaf8446f2001-12-21 21:36:50 +0000243Extension modules
244
Guido van Rossumb57089c2002-08-06 16:20:26 +0000245- The xreadlines module is slated for obsolescence.
246
Guido van Rossum79f0a102002-07-23 03:32:08 +0000247- The strptime function in the time module is now always available (a
248 Python implementation is used when the C library doesn't define it).
249
Guido van Rossum9562bcf2002-06-14 21:31:18 +0000250- The 'new' module is no longer an extension, but a Python module that
251 only exists for backwards compatibility. Its contents are no longer
252 functions but callable type objects.
253
Tim Peters81b92512002-04-29 01:37:32 +0000254- The bsddb.*open functions can now take 'None' as a filename.
Anthony Baxter83888952002-04-23 02:11:05 +0000255 This will create a temporary in-memory bsddb that won't be
Tim Peters81b92512002-04-29 01:37:32 +0000256 written to disk.
Anthony Baxter83888952002-04-23 02:11:05 +0000257
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000258- posix.lchown, posix.killpg, posix.mknod, and posix.getpgid have been
259 added where available.
Martin v. Löwis06a83e92002-04-14 10:19:44 +0000260
Martin v. Löwis2e64c342002-03-27 18:49:02 +0000261- The locale module now exposes the C library's gettext interface.
262
Tim Petersfbf74f22002-03-14 19:06:01 +0000263- A security hole ("double free") was found in zlib-1.1.3, a popular
264 third party compression library used by some Python modules. The
265 hole was quickly plugged in zlib-1.1.4, and the Windows build of
266 Python now ships with zlib-1.1.4.
267
Martin v. Löwis688357e2002-04-08 21:28:20 +0000268- pwd, grp, and resource return enhanced tuples now, with symbolic
269 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +0000270
Martin v. Löwis99866332002-03-01 10:27:01 +0000271- array.array is now a type object. A new format character
272 'u' indicates Py_UNICODE arrays. For those, .tounicode and
273 .fromunicode methods are available. Arrays now support __iadd__
274 and __imul__.
275
Neal Norwitze790eae2002-01-01 21:14:12 +0000276- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +0000277 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
278 is called.
279
Michael W. Hudson34f20ea2002-05-27 15:08:24 +0000280- signal.sigpending, signal.sigprocmask and signal.sigsuspend have
281 been added where available.
282
Tim Petersaf8446f2001-12-21 21:36:50 +0000283Library
284
Guido van Rossum4a57c332002-08-02 18:05:20 +0000285- New "algorithms" module: heapq, implements a heap queue. Thanks to
286 Kevin O'Connor for the code and François Pinard for an entertaining
287 write-up explaining the theory and practical uses of heaps.
288
Marc-André Lemburg58e2ff22002-07-12 14:40:04 +0000289- New encoding for the Palm OS character set: palmos.
290
Tim Peters943382c2002-07-07 03:59:34 +0000291- binascii.crc32() and the zipfile module had problems on some 64-bit
292 platforms. These have been fixed. On a platform with 8-byte C longs,
293 crc32() now returns a signed-extended 4-byte result, so that its value
294 as a Python int is equal to the value computed a 32-bit platform.
295
Martin v. Löwis7d650ca2002-06-30 15:05:00 +0000296- xml.dom.minidom.toxml and toprettyxml now take an optional encoding
297 argument.
298
Guido van Rossum9f7549b2002-06-10 21:39:42 +0000299- Some fixes in the copy module: when an object is copied through its
300 __reduce__ method, there was no check for a __setstate__ method on
301 the result [SF patch 565085]; deepcopy should treat instances of
302 custom metaclasses the same way it treats instances of type 'type'
303 [SF patch 560794].
304
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000305- Sockets now support timeout mode. After s.settimeout(T), where T is
306 a float expressing seconds, subsequent operations raise an exception
307 if they cannot be completed within T seconds. To disable timeout
Guido van Rossum79f0a102002-07-23 03:32:08 +0000308 mode, use s.settimeout(None). There's also a module function,
309 socket.setdefaulttimeout(T), which sets the default for all sockets
310 created henceforth.
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000311
312- getopt.gnu_getopt was added. This supports GNU-style option
313 processing, where options can be mixed with non-option arguments.
Martin v. Löwis446a25f2002-06-06 10:58:36 +0000314
Michael W. Hudsonb0dc1a32002-06-04 18:27:35 +0000315- Stop using strings for exceptions. String objects used for
316 exceptions are now classes deriving from Exception. The objects
317 changed were: Tkinter.TclError, bdb.BdbQuit, macpath.norm_error,
318 tabnanny.NannyNag, and xdrlib.Error.
Neal Norwitzb5b5a262002-06-04 17:14:07 +0000319
Walter Dörwald474458d2002-06-04 15:16:29 +0000320- Constants BOM_UTF8, BOM_UTF16, BOM_UTF16_LE, BOM_UTF16_BE,
321 BOM_UTF32, BOM_UTF32_LE and BOM_UTF32_BE that represent the Byte
322 Order Mark in UTF-8, UTF-16 and UTF-32 encodings for little and
323 big endian systems were added to the codecs module. The old names
324 BOM32_* and BOM64_* were off by a factor of 2.
325
Guido van Rossumf9257822002-06-18 20:43:18 +0000326- Added conversion functions math.degrees() and math.radians().
Raymond Hettinger87f59ee2002-05-13 04:17:32 +0000327
Raymond Hettinger9b1df1d2002-05-12 06:07:21 +0000328- ftplib.retrlines() now tests for callback is None rather than testing
329 for False. Was causing an error when given a callback object which
330 was callable but also returned len() as zero. The change may
331 create new breakage if the caller relied on the undocumented behavior
332 and called with callback set to [] or some other False value not
333 identical to None.
334
Tim Peters46c04e12002-05-05 20:40:00 +0000335- random.gauss() uses a piece of hidden state used by nothing else,
336 and the .seed() and .whseed() methods failed to reset it. In other
337 words, setting the seed didn't completely determine the sequence of
338 results produced by random.gauss(). It does now. Programs repeatedly
339 mixing calls to a seed method with calls to gauss() may see different
340 results now.
341
Fred Drake7f781c92002-05-01 20:33:53 +0000342- The pickle.Pickler class grew a clear_memo() method to mimic that
343 provided by cPickle.Pickler.
344
Tim Peters81b92512002-04-29 01:37:32 +0000345- difflib's SequenceMatcher class now does a dynamic analysis of
346 which elements are so frequent as to constitute noise. For
347 comparing files as sequences of lines, this generally works better
348 than the IS_LINE_JUNK function, and function ndiff's linejunk
349 argument defaults to None now as a result. A happy benefit is
350 that SequenceMatcher may run much faster now when applied
351 to large files with many duplicate lines (for example, C program
352 text with lots of repeated "}" and "return NULL;" lines).
353
Guido van Rossum256705b2002-04-23 13:29:43 +0000354- New Text.dump() method in Tkinter module.
355
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000356- New distutils commands for building packagers were added to
357 support pkgtool on Solaris and swinstall on HP-UX.
358
359- distutils now has a new abstract binary packager base class
360 command/bdist_packager, which simplifies writing packagers.
361 This will hopefully provide the missing bits to encourage
362 people to submit more packagers, e.g. for Debian, FreeBSD
363 and other systems.
364
Guido van Rossumf9257822002-06-18 20:43:18 +0000365- The UTF-16, -LE and -BE stream readers now raise a
366 NotImplementedError for all calls to .readline(). Previously, they
367 used to just produce garbage or fail with an encoding error --
368 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 +0000369 work well with these.
370
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000371- compileall now supports quiet operation.
372
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000373- The BaseHTTPServer now implements optional HTTP/1.1 persistent
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000374 connections.
375
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000376- socket module: the SSL support was broken out of the main
377 _socket module C helper and placed into a new _ssl helper
378 which now gets imported by socket.py if available and working.
379
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000380- encodings package: added aliases for all supported IANA character
381 sets
382
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000383- ftplib: to safeguard the user's privacy, anonymous login will use
384 "anonymous@" as default password, rather than the real user and host
385 name.
386
Fred Drake36736122002-01-10 13:50:31 +0000387- webbrowser: tightened up the command passed to os.system() so that
388 arbitrary shell code can't be executed because a bogus URL was
389 passed in.
390
Tim Peters11bd9942002-02-01 00:52:29 +0000391- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000392 gettext.find an optional all argument. Translations will now fallback
393 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000394
Martin v. Löwis9668b932002-01-12 11:27:42 +0000395- distutils bdist commands now offer a --skip-build option.
396
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000397- warnings.warn now accepts a Warning instance as first argument.
398
Fred Drakefed7e852002-04-04 19:36:15 +0000399- The xml.sax.expatreader.ExpatParser class will no longer create
400 circular references by using itself as the locator that gets passed
401 to the content handler implementation. [SF bug #535474]
402
Barry Warsaw47f3e2c2002-05-20 00:14:24 +0000403- The email.Parser.Parser class now properly parses strings regardless
404 of their line endings, which can be any of \r, \n, or \r\n (CR, LF,
405 or CRLF). Also, the Header class's constructor default arguments
406 has changed slightly so that an explicit maxlinelen value is always
407 honored.
408
Tim Petersaf8446f2001-12-21 21:36:50 +0000409Tools/Demos
410
Fred Drake40813b12002-08-05 15:24:19 +0000411- IDLE supports the new encoding declarations (PEP 263); it can also
412 deal with legacy 8-bit files if they use the locale's encoding. It
413 allows non-ASCII strings in the interactive shell and executes them
414 in the locale's encoding.
Martin v. Löwis98ce7b72002-08-05 15:11:26 +0000415
Marc-André Lemburg46260092002-04-04 16:17:11 +0000416- freeze.py now produces binaries which can import shared modules,
417 unlike before when this failed due to missing symbol exports in
418 the generated binary.
419
Tim Petersaf8446f2001-12-21 21:36:50 +0000420Build
421
Tim Petersf47630f2002-08-01 02:34:51 +0000422- The public Python C API will generally be declared using PyAPI_FUNC
Neal Norwitz1389f3e2002-07-22 13:21:10 +0000423 and PyAPI_DATA macros, while Python extension module init functions
424 will be declared with PyMODINIT_FUNC. DL_EXPORT/DL_IMPORT macros
425 are deprecated.
426
Tim Petersc6a3ff62002-07-08 22:11:52 +0000427- A bug was fixed that could cause COUNT_ALLOCS builds to segfault, or
428 get into infinite loops, when a new-style class got garbage-collected.
429 Unfortunately, to avoid this, the way COUNT_ALLOCS works requires
430 that new-style classes be immortal in COUNT_ALLOCS builds. Note that
431 COUNT_ALLOCS is not enabled by default, in either release or debug
432 builds, and that new-style classes are immortal only in COUNT_ALLOCS
433 builds.
434
Tim Peters943382c2002-07-07 03:59:34 +0000435- Compiling out the cyclic garbage collector is no longer an option.
436 The old symbol WITH_CYCLE_GC is now ignored, and Python.h arranges
437 that it's always defined (for the benefit of any extension modules
438 that may be conditionalizing on it). A bonus is that any extension
439 type participating in cyclic gc can choose to participate in the
440 Py_TRASHCAN mechanism now too; in the absence of cyclic gc, this used
441 to require editing the core to teach the trashcan mechanism about the
442 new type.
443
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000444- According to Annex F of the current C standard,
Tim Peters1de41bf2002-07-03 03:31:20 +0000445
446 The Standard C macro HUGE_VAL and its float and long double analogs,
447 HUGE_VALF and HUGE_VALL, expand to expressions whose values are
448 positive infinities.
449
450 Python only uses the double HUGE_VAL, and only to #define its own symbol
451 Py_HUGE_VAL. Some platforms have incorrect definitions for HUGE_VAL.
452 pyport.h used to try to worm around that, but the workarounds triggered
453 other bugs on other platforms, so we gave up. If your platform defines
454 HUGE_VAL incorrectly, you'll need to #define Py_HUGE_VAL to something
455 that works on your platform. The only instance of this I'm sure about
456 is on an unknown subset of Cray systems, described here:
457
458 http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm
459
460 Presumably 2.3a1 breaks such systems. If anyone uses such a system, help!
461
Martin v. Löwisa3fb4f72002-06-09 13:33:54 +0000462- The configure option --without-doc-strings can be used to remove the
463 doc strings from the builtin functions and modules; this reduces the
464 size of the executable.
465
Tim Peters639295f2002-04-21 07:30:30 +0000466- XXX WITH_UNIVERSAL_NEWLINES Somebody fill this in; the PEP doesn't
467 say how or when to configure it, or how to turn it off.
468
Martin v. Löwis1142de32002-03-29 16:28:31 +0000469- On Unix, a shared libpython2.3.so can be created with --enable-shared.
470
Tim Peters8deda702002-03-30 10:06:07 +0000471- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
472 preprocessor symbols were eliminated. The internal decisions they
473 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000474
Fred Drake7d28b732002-05-02 21:17:00 +0000475- The tools used to build the documentation now work under Cygwin as
476 well as Unix.
477
Skip Montanaro57454e52002-06-14 20:30:31 +0000478- The bsddb and dbm module builds have been changed to try and avoid version
479 skew problems and disable linkage with Berkeley DB 1.85 unless the
480 installer knows what s/he's doing. See the section on building these
481 modules in the README file for details.
482
Tim Petersaf8446f2001-12-21 21:36:50 +0000483C API
484
Guido van Rossumfdb86482002-08-14 21:20:32 +0000485- The Py_InitModule*() functions now accept NULL for the 'methods'
486 argument. Modules without global functions are becoming more common
487 now that factories can be types rather than functions.
488
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +0000489- New C API PyUnicode_FromOrdinal() which exposes unichr() at C
490 level.
491
Thomas Heller085358a2002-07-29 14:27:41 +0000492- New functions PyErr_SetExcFromWindowsErr() and
493 PyErr_SetExcFromWindowsErrWithFilename(). Similar to
494 PyErr_SetFromWindowsErrWithFilename() and
495 PyErr_SetFromWindowsErr(), but they allow to specify
496 the exception type to raise. Available on Windows.
497
Tim Peters7c321a82002-07-09 02:57:01 +0000498- Py_FatalError() is now declared as taking a const char* argument. It
499 was previously declared without const. This should not affect working
500 code.
501
Martin v. Löwis01f94bd2002-05-08 08:44:21 +0000502- Added new macro PySequence_ITEM(o, i) that directly calls
503 sq_item without rechecking that o is a sequence and without
504 adjusting for negative indices.
505
Fred Draked0ba6362002-05-02 21:28:26 +0000506- PyRange_New() now raises ValueError if the fourth argument is not 1.
507 This is part of the removal of deprecated features of the xrange
508 object.
509
Guido van Rossum517c7d42002-04-26 02:49:14 +0000510- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
511 coercion if both arguments have the same type but this type has the
512 CHECKTYPES flag set. This is to better support proxies.
513
Neil Schemenauer9344b142002-04-12 23:00:08 +0000514- The type of tp_free has been changed from "void (*)(PyObject *)" to
515 "void (*)(void *)".
516
517- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
518
Guido van Rossum0986d822002-04-08 01:38:42 +0000519- A type can now inherit its metatype from its base type. Previously,
520 when PyType_Ready() was called, if ob_type was found to be NULL, it
521 was always set to &PyType_Type; now it is set to base->ob_type,
522 where base is tp_base, defaulting to &PyObject_Type.
523
524- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
525
Neil Schemenauerc9abc1d2002-05-08 14:14:41 +0000526- The PyCore_* family of APIs have been removed.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000527
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000528- The "u#" parser marker will now pass through Unicode objects as-is
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000529 without going through the buffer API.
530
Martin v. Löwis7198a522002-01-01 19:59:11 +0000531- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
532
Tim Peters10a3bb52001-12-25 19:07:38 +0000533- An old #define of ANY as void has been removed from pyport.h. This
534 hasn't been used since Python's pre-ANSI days, and the #define has
535 been marked as obsolete since then. SF bug 495548 says it created
536 conflicts with other packages, so keeping it around wasn't harmless.
537
Tim Petersaf8446f2001-12-21 21:36:50 +0000538- Because Python's magic number scheme broke on January 1st, we decided
539 to stop Python development. Thanks for all the fish!
540
Tim Petersfb05db22002-03-11 00:24:00 +0000541- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000542 scheme to a new one. See Python/import.c for details.
543
Tim Petersaf8446f2001-12-21 21:36:50 +0000544New platforms
545
Martin v. Löwisf90ae202002-06-11 06:22:31 +0000546- AtheOS is now supported.
547
Andrew MacIntyre161ad0e2002-08-04 07:25:58 +0000548- the EMX runtime environment on OS/2 is now supported.
549
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000550- GNU/Hurd is now supported.
551
Tim Petersaf8446f2001-12-21 21:36:50 +0000552Tests
553
554Windows
555
Tim Peters08e72952002-04-16 20:48:01 +0000556- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
557 of that has been fixed in the installer (disabled Wise's "delete in-
558 use files" uninstall option).
559
Guido van Rossum181e41a2002-04-06 00:23:25 +0000560- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
561
Tim Peters33187922002-04-04 20:02:04 +0000562- The installer now installs Start menu shortcuts under (the local
563 equivalent of) "All Users" when doing an Admin install.
564
Tim Petersfb05db22002-03-11 00:24:00 +0000565- file.truncate([newsize]) now works on Windows for all newsize values.
566 It used to fail if newsize didn't fit in 32 bits, reflecting a
567 limitation of MS _chsize (which is no longer used).
568
Tim Petersab034fa2002-02-01 11:27:43 +0000569- os.waitpid() is now implemented for Windows, and can be used to block
570 until a specified process exits. This is similar to, but not exactly
571 the same as, os.waitpid() on POSIX systems. If you're waiting for
572 a specific process whose pid was obtained from one of the spawn()
573 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000574 See the docs for details. The docs were changed to clarify that
575 spawn functions return, and waitpid requires, a process handle on
576 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000577
Tim Peters11bd9942002-02-01 00:52:29 +0000578- New tempfile.TemporaryFile implementation for Windows: this doesn't
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000579 need a TemporaryFileWrapper wrapper anymore, and should be immune
Tim Peters11bd9942002-02-01 00:52:29 +0000580 to a nasty problem: before 2.3, if you got a temp file on Windows, it
581 got wrapped in an object whose close() method first closed the
582 underlying file, then deleted the file. This usually worked fine.
583 However, the spawn family of functions on Windows create (at a low C
584 level) the same set of open files in the spawned process Q as were
585 open in the spawning process P. If a temp file f was among them, then
586 doing f.close() in P first closed P's C-level file handle on f, but Q's
587 C-level file handle on f remained open, so the attempt in P to delete f
588 blew up with a "Permission denied" error (Windows doesn't allow
589 deleting open files). This was surprising, subtle, and difficult to
590 work around.
591
592- The os module now exports all the symbolic constants usable with the
593 low-level os.open() on Windows: the new constants in 2.3 are
594 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
595 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
596 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
597 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
598 (so specify both if you want both; note that neither is useful unless
599 specified with O_CREAT too).
600
Tim Petersaf8446f2001-12-21 21:36:50 +0000601Mac
602
603
Tim Peters909c0912001-12-14 23:16:18 +0000604What's New in Python 2.2 final?
605Release date: 21-Dec-2001
606===============================
607
608Type/class unification and new-style classes
609
Barry Warsaw52acb492001-12-21 20:04:22 +0000610- pickle.py, cPickle: allow pickling instances of new-style classes
611 with a custom metaclass.
612
Tim Peters909c0912001-12-14 23:16:18 +0000613Core and builtins
614
Barry Warsaw52acb492001-12-21 20:04:22 +0000615- weakref proxy object: when comparing, unwrap both arguments if both
616 are proxies.
617
Tim Peters909c0912001-12-14 23:16:18 +0000618Extension modules
619
Barry Warsaw52acb492001-12-21 20:04:22 +0000620- binascii.b2a_base64(): fix a potential buffer overrun when encoding
621 very short strings.
622
623- cPickle: the obscure "fast" mode was suspected of causing stack
624 overflows on the Mac. Hopefully fixed this by setting the recursion
625 limit much smaller. If the limit is too low (it only affects
626 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
627 when compiling cPickle.c (or in pyconfig.h).
628
Tim Peters909c0912001-12-14 23:16:18 +0000629Library
630
Barry Warsaw52acb492001-12-21 20:04:22 +0000631- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
632 close or delete time).
633
634- rfc822.py: fixed a bug where the address '<>' was converted to None
635 instead of an empty string (also fixes the email.Utils module).
636
637- xmlrpclib.py: version 1.0.0; uses precision for doubles.
638
639- test suite: the pickle and cPickle tests were not executing any code
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000640 when run from the standard regression test.
Barry Warsaw52acb492001-12-21 20:04:22 +0000641
Tim Peters909c0912001-12-14 23:16:18 +0000642Tools/Demos
643
644Build
645
646C API
647
648New platforms
649
650Tests
651
652Windows
653
Barry Warsaw52acb492001-12-21 20:04:22 +0000654- distutils package: fixed broken Windows installers (bdist_wininst).
655
656- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
657 instances are deleted at process exit time.
658
659- socket.py: prevent mysterious warnings when socket instances are
660 deleted at process exit time.
661
662- posixmodule.c: fix a Windows crash with stat() of a filename ending
663 in backslash.
664
Tim Peters909c0912001-12-14 23:16:18 +0000665Mac
666
Barry Warsaw52acb492001-12-21 20:04:22 +0000667- The Carbon toolbox modules have been upgraded to Universal Headers
668 3.4, and experimental CoreGraphics and CarbonEvents modules have
669 been added. All only for framework-enabled MacOSX.
670
Tim Peters909c0912001-12-14 23:16:18 +0000671
Tim Peters6272dfd2001-12-13 19:34:00 +0000672What's New in Python 2.2c1?
673Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000674===========================
675
676Type/class unification and new-style classes
677
Barry Warsaw06557452001-12-14 20:47:12 +0000678- Guido's tutorial introduction to the new type/class features has
679 been extensively updated. See
680
681 http://www.python.org/2.2/descrintro.html
682
683 That remains the primary documentation in this area.
684
Guido van Rossum33bab012001-12-05 22:45:48 +0000685- Fixed a leak: instance variables declared with __slots__ were never
686 deleted!
687
Guido van Rossum4b800852001-12-03 00:54:52 +0000688- The "delete attribute" method of descriptor objects is called
689 __delete__, not __del__. In previous releases, it was mistakenly
690 called __del__, which created an unfortunate overloading condition
691 with finalizers. (The "get attribute" and "set attribute" methods
692 are still called __get__ and __set__, respectively.)
693
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000694- Some subtle issues with the super built-in were fixed:
695
696 (a) When super itself is subclassed, its __get__ method would still
697 return an instance of the base class (i.e., of super).
698
699 (b) super(C, C()).__class__ would return C rather than super. This
700 is confusing. To fix this, I decided to change the semantics of
701 super so that it only applies to code attributes, not to data
702 attributes. After all, overriding data attributes is not
703 supported anyway.
704
705 (c) The __get__ method didn't check whether the argument was an
706 instance of the type used in creation of the super instance.
707
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000708- Previously, hash() of an instance of a subclass of a mutable type
709 (list or dictionary) would return some value, rather than raising
710 TypeError. This has been fixed. Also, directly calling
711 dict.__hash__ and list.__hash__ now raises the same TypeError
712 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000713
Guido van Rossumd331cb52001-12-05 19:46:42 +0000714- New-style objects now support deleting their __dict__. This is for
715 all intents and purposes equivalent to assigning a brand new empty
716 dictionary, but saves space if the object is not used further.
717
Tim Petersb3c9af12001-11-17 00:21:57 +0000718Core and builtins
719
Tim Peters3caca232001-12-06 06:23:26 +0000720- -Qnew now works as documented in PEP 238: when -Qnew is passed on
721 the command line, all occurrences of "/" use true division instead
722 of classic division. See the PEP for details. Note that "all"
723 means all instances in library and 3rd-party modules, as well as in
724 your own code. As the PEP says, -Qnew is intended for use only in
725 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000726 Note that test_coercion.py in the standard Python test suite fails
727 under -Qnew; this is expected, and won't be repaired until true
728 division becomes the default (in the meantime, test_coercion is
729 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000730
Fred Drake6c01e252001-12-14 17:08:12 +0000731- complex() now only allows the first argument to be a string
732 argument, and raises TypeError if either the second arg is a string
733 or if the second arg is specified when the first is a string.
734
Tim Petersb3c9af12001-11-17 00:21:57 +0000735Extension modules
736
Martin v. Löwis560da622001-11-24 09:24:51 +0000737- gc.get_referents was renamed to gc.get_referrers.
738
Tim Petersb3c9af12001-11-17 00:21:57 +0000739Library
740
Tim Peters25059d32001-12-07 20:35:43 +0000741- Functions in the os.spawn() family now release the global interpreter
742 lock around calling the platform spawn. They should always have done
743 this, but did not before 2.2c1. Multithreaded programs calling
744 an os.spawn function with P_WAIT will no longer block all Python threads
745 until the spawned program completes. It's possible that some programs
746 relies on blocking, although more likely by accident than by design.
747
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000748- webbrowser defaults to netscape.exe on OS/2 now.
749
Martin v. Löwis652e1912001-11-25 14:50:56 +0000750- Tix.ResizeHandle exposes detach_widget, hide, and show.
751
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000752- The charset alias windows_1252 has been added.
753
Barry Warsaw06557452001-12-14 20:47:12 +0000754- types.StringTypes is a tuple containing the defined string types;
755 usually this will be (str, unicode), but if Python was compiled
756 without Unicode support it will be just (str,).
757
758- The pulldom and minidom modules were synchronized to PyXML.
759
Tim Petersb3c9af12001-11-17 00:21:57 +0000760Tools/Demos
761
Barry Warsaw06557452001-12-14 20:47:12 +0000762- A new script called Tools/scripts/google.py was added, which fires
763 off a search on Google.
764
Tim Petersb3c9af12001-11-17 00:21:57 +0000765Build
766
Barry Warsaw06557452001-12-14 20:47:12 +0000767- Note that release builds of Python should arrange to define the
768 preprocessor symbol NDEBUG on the command line (or equivalent).
769 In the 2.2 pre-release series we tried to define this by magic in
770 Python.h instead, but it proved to cause problems for extension
771 authors. The Unix, Windows and Mac builds now all define NDEBUG in
772 release builds via cmdline (or equivalent) instead. Ports to
773 other platforms should do likewise.
774
Jack Jansen1999ef42001-12-06 21:47:20 +0000775- It is no longer necessary to use --with-suffix when building on a
776 case-insensitive file system (such as Mac OS X HFS+). In the build
777 directory an extension is used, but not in the installed python.
778
Tim Petersb3c9af12001-11-17 00:21:57 +0000779C API
780
Tim Petersf582b822001-12-11 18:51:08 +0000781- New function PyDict_MergeFromSeq2() exposes the builtin dict
782 constructor's logic for updating a dictionary from an iterable object
783 producing key-value pairs.
784
Tim Peterscffed4b2001-11-29 03:26:37 +0000785- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000786 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000787 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
788 dump core in some bad cases. This has been repaired. As a result,
789 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
790 previously went unchallenged.
791
Tim Petersb3c9af12001-11-17 00:21:57 +0000792New platforms
793
794Tests
795
796Windows
797
798Mac
799
Jack Jansenffa260f2001-12-06 21:14:00 +0000800- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
801 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000802
Barry Warsaw06557452001-12-14 20:47:12 +0000803- Changed logic for finding python home in Mac OS X framework Pythons.
804 Now sys.executable points to the executable again, in stead of to
805 the shared library. The latter is used only for locating the python
806 home.
807
808
Tim Peters84362bc2001-10-19 17:55:30 +0000809What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000810Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000811===========================
812
813Type/class unification and new-style classes
814
Guido van Rossum3d27df02001-11-15 20:27:54 +0000815- Multiple inheritance mixing new-style and classic classes in the
816 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000817
818 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000819 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000820
821 The MRO (method resolution order) for each base class is respected
822 according to its kind, but the MRO for the derived class is computed
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000823 using new-style MRO rules if any base class is a new-style class.
Tim Peters76f7fe32001-11-15 20:02:21 +0000824 This needs to be documented.
825
Tim Petersa427a2b2001-10-29 22:25:45 +0000826- The new builtin dictionary() constructor, and dictionary type, have
827 been renamed to dict. This reflects a decade of common usage.
828
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000829- dict() now accepts an iterable object producing 2-sequences. For
830 example, dict(d.items()) == d for any dictionary d. The argument,
831 and the elements of the argument, can be any iterable objects.
832
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000833- New-style classes can now have a __del__ method, which is called
834 when the instance is deleted (just like for classic classes).
835
Guido van Rossum12d955c2001-10-26 14:56:06 +0000836- Assignment to object.__dict__ is now possible, for objects that are
837 instances of new-style classes that have a __dict__ (unless the base
838 class forbids it).
839
Guido van Rossumc8e56452001-10-22 00:43:43 +0000840- Methods of built-in types now properly check for keyword arguments
841 (formerly these were silently ignored). The only built-in methods
842 that take keyword arguments are __call__, __init__ and __new__.
843
Guido van Rossum86443212001-10-27 22:28:54 +0000844- The socket function has been converted to a type; see below.
845
Tim Peters84362bc2001-10-19 17:55:30 +0000846Core and builtins
847
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000848- Assignment to __debug__ raises SyntaxError at compile-time. This
849 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000850 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000851
Guido van Rossum12d955c2001-10-26 14:56:06 +0000852- Clarified the error messages for unsupported operands to an operator
853 (like 1 + '').
854
Tim Peters84362bc2001-10-19 17:55:30 +0000855Extension modules
856
Tim Peters5ebfd362001-11-13 23:11:19 +0000857- mmap has a new keyword argument, "access", allowing a uniform way for
858 both Windows and Unix users to create read-only, write-through and
859 copy-on-write memory mappings. This was previously possible only on
860 Unix. A new keyword argument was required to support this in a
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000861 uniform way because the mmap() signatures had diverged across
Tim Peters5ebfd362001-11-13 23:11:19 +0000862 platforms. Thanks to Jay T Miller for repairing this!
863
Tim Peters169ded02001-11-03 19:57:21 +0000864- By default, the gc.garbage list now contains only those instances in
865 unreachable cycles that have __del__ methods; in 2.1 it contained all
866 instances in unreachable cycles. "Instances" here has been generalized
867 to include instances of both new-style and old-style classes.
868
Guido van Rossum12d955c2001-10-26 14:56:06 +0000869- The socket module defines a new method for socket objects,
870 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000871 send() until all data has been sent. Also, the socket function has
872 been converted to a subclassable type, like list and tuple (etc.)
873 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000874
875- Various bugfixes to the curses module. There is now a test suite
876 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000877
Guido van Rossum692adf12001-10-30 03:03:03 +0000878- binascii.b2a_base64 no longer places an arbitrary restriction of 57
879 bytes on its input.
880
Tim Peters84362bc2001-10-19 17:55:30 +0000881Library
882
Tim Peters5ebfd362001-11-13 23:11:19 +0000883- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000884 convenience function.
885
Tim Peters75335872001-11-03 19:35:43 +0000886- Symbolic group names in regular expressions must be unique. For
887 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
888 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000889 Python 2.2 detects this error at regexp compilation time;
890 previously, the error went undetected, and results were
891 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
892 pattern.subn() methods have been rewritten in C. Also, an
893 experimental function/method finditer() has been added, which works
894 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000895
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000896- Tix exposes more commands through the classes DirSelectBox,
897 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
898 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
899 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
900
Tim Peters98791af2001-10-23 01:59:54 +0000901- Traceback objects are now scanned by cyclic garbage collection, so
902 cycles created by casual use of sys.exc_info() no longer cause
903 permanent memory leaks (provided garbage collection is enabled).
904
Guido van Rossum49192142001-10-24 20:51:44 +0000905- os.extsep -- a new variable needed by the RISCOS support. It is the
906 separator used by extensions, and is '.' on all platforms except
907 RISCOS, where it is '/'. There is no need to use this variable
908 unless you have a masochistic desire to port your code to RISCOS.
909
Barry Warsaw012852b2001-11-16 16:17:27 +0000910- mimetypes.py has optional support for non-standard, but commonly
911 found types. guess_type() and guess_extension() now accept an
912 optional `strict' flag, defaulting to true, which controls whether
913 recognize non-standard types or not. A few non-standard types we
914 know about have been added. Also, when run as a script, there are
915 new -l and -e options.
916
917- statcache is now deprecated.
918
919- email.Utils.formatdate() now produces the preferred RFC 2822 style
920 dates with numeric timezones (it used to produce obsolete dates
921 hard coded to "GMT" timezone). An optional `localtime' flag is
922 added to produce dates in the local timezone, with daylight savings
923 time properly taken into account.
924
925- In pickle and cPickle, instead of masking errors in load() by
926 transforming them into SystemError, we let the original exception
927 propagate out. Also, implement support for __safe_for_unpickling__
928 in pickle, as it already was supported in cPickle.
929
Tim Peters84362bc2001-10-19 17:55:30 +0000930Tools/Demos
931
932Build
933
Barry Warsaw012852b2001-11-16 16:17:27 +0000934- The dbm module is built using libdb1 if available. The bsddb module
935 is built with libdb3 if available.
936
937- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
938
Tim Peters84362bc2001-10-19 17:55:30 +0000939C API
940
Tim Peters1fc240e2001-10-26 05:06:50 +0000941- New function PySequence_Fast_GET_SIZE() returns the size of a non-
942 NULL result from PySequence_Fast(), more quickly than calling
943 PySequence_Size().
944
Barry Warsaw012852b2001-11-16 16:17:27 +0000945- New argument unpacking function PyArg_UnpackTuple() added.
946
947- New functions PyObject_CallFunctionObjArgs() and
948 PyObject_CallMethodObjArgs() have been added to make it more
949 convenient and efficient to call functions and methods from C.
950
951- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
952 possible that this will propagate errors it didn't before.
953
954- New function PyObject_CheckReadBuffer(), which returns true if its
955 argument supports the single-segment readable buffer interface.
956
Tim Peters84362bc2001-10-19 17:55:30 +0000957New platforms
958
Guido van Rossum86443212001-10-27 22:28:54 +0000959- We've finally confirmed that this release builds on HP-UX 11.00,
960 *with* threads, and passes the test suite.
961
Tim Peters7a33d8b2001-11-05 02:51:07 +0000962- Thanks to a series of patches from Michael Muller, Python may build
963 again under OS/2 Visual Age C++.
964
Guido van Rossum49192142001-10-24 20:51:44 +0000965- Updated RISCOS port by Dietmar Schwertberger.
966
Tim Peters84362bc2001-10-19 17:55:30 +0000967Tests
968
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000969- Added a test script for the curses module. It isn't run automatically;
970 regrtest.py must be run with '-u curses' to enable it.
971
Tim Peters84362bc2001-10-19 17:55:30 +0000972Windows
973
Barry Warsaw012852b2001-11-16 16:17:27 +0000974Mac
975
976- PythonScript has been moved to unsupported and is slated to be
977 removed completely in the next release.
978
979- It should now be possible to build applets that work on both OS9 and
980 OSX.
981
982- The core is now linked with CoreServices not Carbon; as a side
983 result, default 8bit encoding on OSX is now ASCII.
984
985- Python should now build on OSX 10.1.1
986
Tim Peters84362bc2001-10-19 17:55:30 +0000987
Tim Petersabf925f2001-09-28 21:53:42 +0000988What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000989Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000990===========================
991
992Type/class unification and new-style classes
993
Guido van Rossum687ae002001-10-15 22:03:32 +0000994- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000995 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000996 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000997 remains: the __dict__ of a new-style class is a read-only proxy; you
998 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000999 __defined__ attribute of new-style types no longer exists, for lack
1000 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001001 future a __cache__ may be resurrected with a similar function, if I
1002 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +00001003
Tim Peters1c9ca872001-10-04 06:43:12 +00001004- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
1005 always returned None, even when there was a class docstring).
1006
1007- doctest now finds and runs docstrings attached to new-style classes,
1008 class methods, static methods, and properties.
1009
Guido van Rossum9074ef62001-10-16 21:34:49 +00001010Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +00001011
Guido van Rossuma8bcf802001-10-15 15:53:58 +00001012- A very subtle syntactical pitfall in list comprehensions was fixed.
1013 For example: [a+b for a in 'abc', for b in 'def']. The comma in
1014 this example is a mistake. Previously, this would silently let 'a'
1015 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
1016 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
1017 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
1018 Note that [a for a in <singleton>] is a convoluted way to say
1019 [<singleton>] anyway, so it's not like any expressiveness is lost.
1020
Guido van Rossum9074ef62001-10-16 21:34:49 +00001021- getattr(obj, name, default) now only catches AttributeError, as
1022 documented, rather than returning the default value for all
1023 exceptions (which could mask bugs in a __getattr__ hook, for
1024 example).
1025
Fred Drakecb7a6b52001-10-22 18:41:51 +00001026- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +00001027 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001028 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +00001029 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +00001030
Guido van Rossum1c486092001-10-19 02:05:35 +00001031- unicode(obj) now behaves more like str(obj), accepting arbitrary
1032 objects, and calling a __unicode__ method if it exists.
1033 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +00001034 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +00001035
Barry Warsawf6fb1712001-10-19 05:35:40 +00001036- isinstance() now allows any object as the first argument and a
1037 class, a type or something with a __bases__ tuple attribute for the
1038 second argument. The second argument may also be a tuple of a
1039 class, type, or something with __bases__, in which case isinstance()
1040 will return true if the first argument is an instance of any of the
1041 things contained in the second argument tuple. E.g.
1042
1043 isinstance(x, (A, B))
1044
1045 returns true if x is an instance of A or B.
1046
Guido van Rossum9074ef62001-10-16 21:34:49 +00001047Extension modules
1048
1049- thread.start_new_thread() now returns the thread ID (previously None).
1050
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001051- binascii has now two quopri support functions, a2b_qp and b2a_qp.
1052
Guido van Rossumc524d952001-10-19 01:31:59 +00001053- readline now supports setting the startup_hook and the
1054 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +00001055
Guido van Rossumc524d952001-10-19 01:31:59 +00001056- os and posix supports chroot(), setgroups() and unsetenv() where
1057 available. The stat(), fstat(), statvfs() and fstatvfs() functions
1058 now return "pseudo-sequences" -- the various fields can now be
1059 accessed as attributes (e.g. os.stat("/").st_mtime) but for
1060 backwards compatibility they also behave as a fixed-length sequence.
1061 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +00001062 attributes.
1063
1064- time: localtime(), gmtime() and strptime() now return a
1065 pseudo-sequence similar to the os.stat() return value, with
1066 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +00001067
Guido van Rossum9074ef62001-10-16 21:34:49 +00001068- Decompression objects in the zlib module now accept an optional
1069 second parameter to decompress() that specifies the maximum amount
1070 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +00001071
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001072- optional SSL support in the socket module now exports OpenSSL
1073 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
1074 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +00001075 automatically seed its PRNG. Also, the keyfile and certfile
1076 arguments to socket.ssl() are now optional.
1077
1078- posixmodule (and by extension, the os module on POSIX platforms) now
1079 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001080
Guido van Rossum9074ef62001-10-16 21:34:49 +00001081Library
Guido van Rossum3c288632001-10-16 21:13:49 +00001082
Tim Peters7402f792001-10-02 03:53:41 +00001083- doctest now excludes functions and classes not defined by the module
1084 being tested, thanks to Tim Hochberg.
1085
Fred Drakecb7a6b52001-10-22 18:41:51 +00001086- HotShot, a new profiler implemented using a C-based callback, has
1087 been added. This substantially reduces the overhead of profiling,
1088 but it is still quite preliminary. Support modules and
1089 documentation will be added in upcoming releases (before 2.2 final).
1090
Guido van Rossumc4b09b42001-10-04 10:19:00 +00001091- profile now produces correct output in situations where an exception
1092 raised in Python is cleared by C code (e.g. hasattr()). This used
1093 to cause wrong output, including spurious claims of recursive
1094 functions and attribution of time spent to the wrong function.
1095
Tim Peters0a1fc4e2001-10-07 03:12:08 +00001096 The code and documentation for the derived OldProfile and HotProfile
1097 profiling classes was removed. The code hasn't worked for years (if
1098 you tried to use them, they raised exceptions). OldProfile
1099 intended to reproduce the behavior of the profiler Python used more
1100 than 7 years ago, and isn't interesting anymore. HotProfile intended
1101 to provide a faster profiler (but producing less information), and
1102 that's a worthy goal we intend to meet via a different approach (but
1103 without losing information).
1104
Tim Peterscce092d2001-10-09 05:31:56 +00001105- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +00001106 a much better system-specific calibration constant. The constant can
1107 now be specified in an instance constructor, or as a Profile class or
1108 instance variable, instead of by editing profile.py's source code.
1109 Calibration must still be done manually (see the docs for the profile
1110 module).
1111
1112 Note that Profile.calibrate() must be overriden by subclasses.
1113 Improving the accuracy required exploiting detailed knowledge of
1114 profiler internals; the earlier method abstracted away the details
1115 and measured a simplified model instead, but consequently computed
1116 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +00001117
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001118- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +00001119 which indicates whether output is intended for the header 'Q'
1120 encoding.
1121
Guido van Rossuma5343cc2001-10-18 18:02:07 +00001122- The SocketServer.ThreadingMixIn class now closes the request after
1123 finish_request() returns. (Not when it errors out though.)
1124
Barry Warsawf6fb1712001-10-19 05:35:40 +00001125- The nntplib module's NNTP.body() method has grown a `file' argument
1126 to allow saving the message body to a file.
1127
1128- The email package has added a class email.Parser.HeaderParser which
1129 only parses headers and does not recurse into the message's body.
1130 Also, the module/class MIMEAudio has been added for representing
1131 audio data (contributed by Anthony Baxter).
1132
1133- ftplib should be able to handle files > 2GB.
1134
1135- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
1136 ON, and OFF.
1137
Fred Drakecb7a6b52001-10-22 18:41:51 +00001138- xml.dom.minidom NodeList objects now support the length attribute
1139 and item() method as required by the DOM specifications.
1140
Guido van Rossumed554f62001-10-02 23:15:37 +00001141Tools/Demos
1142
1143- Demo/dns was removed. It no longer serves any purpose; a package
1144 derived from it is now maintained by Anthony Baxter, see
1145 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +00001146
Barry Warsawf6fb1712001-10-19 05:35:40 +00001147- The freeze tool has been made more robust, and two new options have
1148 been added: -X and -E.
1149
Tim Petersabf925f2001-09-28 21:53:42 +00001150Build
1151
Barry Warsawf6fb1712001-10-19 05:35:40 +00001152- configure will use CXX in LINKCC if CXX is used to build main() and
1153 the system requires to link a C++ main using the C++ compiler.
1154
Tim Petersabf925f2001-09-28 21:53:42 +00001155C API
1156
Guido van Rossum6c4bce32001-10-18 19:20:25 +00001157- The documentation for the tp_compare slot is updated to require that
1158 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
1159 not correct. This is not yet enforced but will be enforced in
1160 Python 2.3; even later, we may use -2 to indicate errors and +2 for
1161 "NotImplemented". Right now, -1 should be used for an error return.
1162
Tim Petersd38b1c72001-09-30 05:09:37 +00001163- PyLong_AsLongLong() now accepts int (as well as long) arguments.
1164 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
1165 as long) arguments.
1166
Guido van Rossum3c288632001-10-16 21:13:49 +00001167- PyThread_start_new_thread() now returns a long int giving the thread
1168 ID, if one can be calculated; it returns -1 for error, 0 if no
1169 thread ID is calculated (this is an incompatible change, but only
1170 the thread module used this API). This code has only really been
1171 tested on Linux and Windows; other platforms please beware (and
1172 report any bugs or strange behavior).
1173
Guido van Rossum1c486092001-10-19 02:05:35 +00001174- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
1175 input.
1176
Tim Petersabf925f2001-09-28 21:53:42 +00001177New platforms
1178
1179Tests
1180
1181Windows
1182
Tim Peters04cf1d32001-10-09 22:39:40 +00001183- Installer: If you install IDLE, and don't disable file-extension
1184 registration, a new "Edit with IDLE" context (right-click) menu entry
1185 is created for .py and .pyw files.
1186
Tim Peters1ce3cf72001-10-01 17:58:40 +00001187- The signal module now supports SIGBREAK on Windows, thanks to Steven
1188 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
1189 action remains to call Win32 ExitProcess(). This can be changed via
1190 signal.signal(). For example:
1191
1192 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
1193 # (SIGINT) behavior.
1194 import signal
1195 signal.signal(signal.SIGBREAK,
1196 signal.default_int_handler)
1197
1198 try:
1199 while 1:
1200 pass
1201 except KeyboardInterrupt:
1202 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
1203 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
1204 # program without the possibility for any Python-level cleanup).
1205 print "Clean exit"
1206
Tim Petersabf925f2001-09-28 21:53:42 +00001207
Tim Petersb07352e2001-09-08 01:25:47 +00001208What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001209Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +00001210===========================
1211
Guido van Rossum808eea72001-09-25 04:15:41 +00001212Type/class unification and new-style classes
1213
1214- pydoc and inspect are now aware of new-style classes;
1215 e.g. help(list) at the interactive prompt now shows proper
1216 documentation for all operations on list objects.
1217
1218- Applications using Jim Fulton's ExtensionClass module can now safely
1219 be used with Python 2.2. In particular, Zope 2.4.1 now works with
1220 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
1221 examples also work again. It is hoped that Gtk and Boost also work
1222 with 2.2a4 and beyond. (If you can confirm this, please write
1223 webmaster@python.org; if there are still problems, please open a bug
1224 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +00001225
Tim Peters66c1a522001-09-24 21:17:50 +00001226- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001227 These map to read-only attributes 'fget', 'fset', 'fdel', and '__doc__'
Tim Peters66c1a522001-09-24 21:17:50 +00001228 in the constructed property object. fget, fset and fdel weren't
1229 discoverable from Python in 2.2a3. __doc__ is new, and allows to
1230 associate a docstring with a property.
1231
Guido van Rossum808eea72001-09-25 04:15:41 +00001232- Comparison overloading is now more completely implemented. For
1233 example, a str subclass instance can properly be compared to a str
1234 instance, and it can properly overload comparison. Ditto for most
1235 other built-in object types.
1236
1237- The repr() of new-style classes has changed; instead of <type
1238 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
1239 *except* for built-in types, which are still rendered as <type
1240 'Foo'> (to avoid upsetting existing code that might parse or
1241 otherwise rely on repr() of certain type objects).
1242
1243- The repr() of new-style objects is now always <Foo object at XXX>;
1244 previously, it was sometimes <Foo instance at XXX>.
1245
1246- For new-style classes, what was previously called __getattr__ is now
1247 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001248 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +00001249 one in classic classes is defined which is called only if regular
1250 attribute access raises AttributeError; to catch *all* attribute
1251 access, you can use __getattribute__ (for new-style classes). If
1252 both are defined, __getattribute__ is called first, and if it raises
1253 AttributeError, __getattr__ is called.
1254
1255- The __class__ attribute of new-style objects can be assigned to.
1256 The new class must have the same C-level object layout as the old
1257 class.
1258
1259- The builtin file type can be subclassed now. In the usual pattern,
1260 "file" is the name of the builtin type, and file() is a new builtin
1261 constructor, with the same signature as the builtin open() function.
1262 file() is now the preferred way to open a file.
1263
1264- Previously, __new__ would only see sequential arguments passed to
1265 the type in a constructor call; __init__ would see both sequential
1266 and keyword arguments. This made no sense whatsoever any more, so
1267 now both __new__ and __init__ see all arguments.
1268
1269- Previously, hash() applied to an instance of a subclass of str or
1270 unicode always returned 0. This has been repaired.
1271
1272- Previously, an operation on an instance of a subclass of an
1273 immutable type (int, long, float, complex, tuple, str, unicode),
1274 where the subtype didn't override the operation (and so the
1275 operation was handled by the builtin type), could return that
1276 instance instead a value of the base type. For example, if s was of
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001277 a str subclass type, s[:] returned s as-is. Now it returns a str
Guido van Rossum808eea72001-09-25 04:15:41 +00001278 with the same value as s.
1279
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001280- Provisional support for pickling new-style objects has been added.
1281
Guido van Rossum808eea72001-09-25 04:15:41 +00001282Core
1283
Tim Peters2c9aa5e2001-09-23 04:06:05 +00001284- file.writelines() now accepts any iterable object producing strings.
1285
Marc-André Lemburgaefd7662001-09-20 12:59:37 +00001286- PyUnicode_FromEncodedObject() now works very much like
1287 PyObject_Str(obj) in that it tries to use __str__/tp_str
1288 on the object if the object is not a string or buffer. This
1289 makes unicode() behave like str() when applied to non-string/buffer
1290 objects.
1291
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001292- PyFile_WriteObject now passes Unicode objects to the file's write
1293 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +00001294 of a print statement must support Unicode objects, i.e. they must
1295 at least convert them into ASCII strings.
1296
Guido van Rossum624c8af2001-09-18 15:21:04 +00001297- Thread scheduling on Solaris should be improved; it is no longer
1298 necessary to insert a small sleep at the start of a thread in order
1299 to let other runnable threads be scheduled.
1300
Tim Petersb07352e2001-09-08 01:25:47 +00001301Library
1302
Marc-André Lemburgbf990172001-09-27 14:17:33 +00001303- StringIO.StringIO instances and cStringIO.StringIO instances support
1304 read character buffer compatible objects for their .write() methods.
1305 These objects are converted to strings and then handled as such
1306 by the instances.
1307
Barry Warsaw2f600732001-09-24 04:28:10 +00001308- The "email" package has been added. This is basically a port of the
1309 mimelib package <http://sf.net/projects/mimelib> with API changes
1310 and some implementations updated to use iterators and generators.
1311
Tim Peters8a9c2842001-09-22 21:30:22 +00001312- difflib.ndiff() and difflib.Differ.compare() are generators now. This
1313 restores the ability of Tools/scripts/ndiff.py to start producing output
1314 before the entire comparison is complete.
1315
Barry Warsaw58b072d2001-09-22 04:44:21 +00001316- StringIO.StringIO instances and cStringIO.StringIO instances support
1317 iteration just like file objects (i.e. their .readline() method is
1318 called for each iteration until it returns an empty string).
1319
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +00001320- The codecs module has grown four new helper APIs to access
1321 builtin codecs: getencoder(), getdecoder(), getreader(),
1322 getwriter().
1323
Guido van Rossum624c8af2001-09-18 15:21:04 +00001324- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
1325 simplifies writing XML RPC servers.
1326
Barry Warsaw647d5e82001-09-28 17:01:02 +00001327- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +00001328 after interpretation of symbolic links. On non-Unix systems, this
1329 is an alias for os.path.abspath().
1330
Tim Peters16a77ad2001-09-08 04:00:12 +00001331- operator.indexOf() (PySequence_Index() in the C API) now works with any
1332 iterable object.
1333
Guido van Rossum624c8af2001-09-18 15:21:04 +00001334- smtplib now supports various authentication and security features of
1335 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001336
Guido van Rossum624c8af2001-09-18 15:21:04 +00001337- hmac: a new module implementing keyed hashing for message
1338 authentication.
1339
1340- mimetypes now recognizes more extensions and file types. At the
1341 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001342
Guido van Rossum624c8af2001-09-18 15:21:04 +00001343- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001344 Python 2.2 bytecode generation. It has also been promoted from a
1345 Tool to a standard library package. (Tools/compiler still exists as
1346 a sample driver.)
1347
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001348Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +00001349
Tim Petersb07352e2001-09-08 01:25:47 +00001350Build
1351
Guido van Rossum624c8af2001-09-18 15:21:04 +00001352- Large file support (LFS) is now automatic when the platform supports
1353 it; no more manual configuration tweaks are needed. On Linux, at
1354 least, it's possible to have a system whose C library supports large
1355 files but whose kernel doesn't; in this case, large file support is
1356 still enabled but doesn't do you any good unless you upgrade your
1357 kernel or share your Python executable with another system whose
1358 kernel has large file support.
1359
1360- The configure script now supplies plausible defaults in a
1361 cross-compilation environment. This doesn't mean that the supplied
1362 values are always correct, or that cross-compilation now works
1363 flawlessly -- but it's a first step (and it shuts up most of
1364 autoconf's warnings about AC_TRY_RUN).
1365
1366- The Unix build is now a bit less chatty, courtesy of the parser
1367 generator. The build is completely silent (except for errors) when
1368 using "make -s", thanks to a -q option to setup.py.
1369
Tim Petersb07352e2001-09-08 01:25:47 +00001370C API
1371
Guido van Rossum624c8af2001-09-18 15:21:04 +00001372- The "structmember" API now supports some new flag bits to deny read
1373 and/or write access to attributes in restricted execution mode.
1374
Tim Petersb07352e2001-09-08 01:25:47 +00001375New platforms
1376
Guido van Rossum624c8af2001-09-18 15:21:04 +00001377- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1378 (http://familiar.handhelds.org).
1379
Tim Petersb07352e2001-09-08 01:25:47 +00001380Tests
1381
Tim Peters8a9c2842001-09-22 21:30:22 +00001382- The "classic" standard tests, which work by comparing stdout to
1383 an expected-output file under Lib/test/output/, no longer stop at
1384 the first mismatch. Instead the test is run to completion, and a
1385 variant of ndiff-style comparison is used to report all differences.
1386 This is much easier to understand than the previous style of reporting.
1387
1388- The unittest-based standard tests now use regrtest's test_main()
1389 convention, instead of running as a side-effect of merely being
1390 imported. This allows these tests to be run in more natural and
1391 flexible ways as unittests, outside the regrtest framework.
1392
1393- regrtest.py is much better integrated with unittest and doctest now,
1394 especially in regard to reporting errors.
1395
Tim Petersb07352e2001-09-08 01:25:47 +00001396Windows
1397
Guido van Rossum624c8af2001-09-18 15:21:04 +00001398- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001399 that support it (NTFS under Windows 2000). See "What's New in
1400 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001401
Tim Petersb07352e2001-09-08 01:25:47 +00001402
Tim Petersedc99312001-08-22 21:36:50 +00001403What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001404Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001405===========================
1406
1407Core
1408
Tim Peters9fffa3e2001-09-04 05:14:19 +00001409- Conversion of long to float now raises OverflowError if the long is too
1410 big to represent as a C double.
1411
Tim Peters32f453e2001-09-03 08:35:41 +00001412- The 3-argument builtin pow() no longer allows a third non-None argument
1413 if either of the first two arguments is a float, or if both are of
1414 integer types and the second argument is negative (in which latter case
1415 the arguments are converted to float, so this is really the same
1416 restriction).
1417
Tim Peters5d2b77c2001-09-03 05:47:38 +00001418- The builtin dir() now returns more information, and sometimes much
1419 more, generally naming all attributes of an object, and all attributes
1420 reachable from the object via its class, and from its class's base
1421 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1422 an empty list. In 2.2a3,
1423
1424 >>> dir([])
1425 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1426 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1427 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1428 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1429 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1430 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1431 'reverse', 'sort']
1432
1433 dir(module) continues to return only the module's attributes, though.
1434
Tim Petersbdee63f2001-09-02 03:40:59 +00001435- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001436 than raising OverflowError. This is a partial implementation of PEP
1437 237. You can use -Wdefault::OverflowWarning to enable a warning for
1438 this situation, and -Werror::OverflowWarning to revert to the old
1439 OverflowError exception.
1440
Guido van Rossum61c345f2001-09-04 03:26:15 +00001441- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001442 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001443 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1444 -Qold, meaning the / operator has its classic meaning and no
1445 warnings are issued. Using -Qwarn issues a run-time warning about
1446 all uses of classic division for int and long arguments; -Qwarnall
1447 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001448 (for use with fixdiv.py).
1449 [Note: the remainder of this paragraph (preserved below) became
1450 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1451 <obsolete>
1452 Using -Qnew is questionable; it turns on new division by default, but
1453 only in the __main__ module. You can usefully combine -Qwarn or
1454 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1455 warns about classic division everywhere else.
1456 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001457
Tim Petersbdee63f2001-09-02 03:40:59 +00001458- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001459 long, float, str, unicode, and tuple. (The types complex, list and
1460 dictionary can also be subclassed; this was introduced earlier.)
1461 Note that restrictions apply when subclassing immutable built-in
1462 types: you can only affect the value of the instance by overloading
1463 __new__. You can add mutable attributes, and the subclass instances
1464 will have a __dict__ attribute, but you cannot change the "value"
1465 (as implemented by the base class) of an immutable subclass instance
1466 once it is created.
1467
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001468- The dictionary constructor now takes an optional argument, a
1469 mapping-like object, and initializes the dictionary from its
1470 (key, value) pairs.
1471
Tim Petersbdee63f2001-09-02 03:40:59 +00001472- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001473 "cooperative super calls" in a multiple inheritance setting. For an
1474 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1475
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001476- A new built-in type, property, has been added. This enables the
1477 creation of "properties". These are attributes implemented by
1478 getter and setter functions (or only one of these for read-only or
1479 write-only attributes), without the need to override __getattr__.
1480 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001481
Tim Petersbdee63f2001-09-02 03:40:59 +00001482- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001483 liberalized, to allow leading zeroes. Examples of literals now
1484 legal that were SyntaxErrors before:
1485
1486 00.0 0e3 0100j 07.5 00000000000000000008.
1487
Tim Petersbdee63f2001-09-02 03:40:59 +00001488- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001489 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1490
Tim Petersedc99312001-08-22 21:36:50 +00001491Library
1492
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001493- telnetlib includes symbolic names for the options, and support for
1494 setting an option negotiation callback.
1495
Tim Petersa40c7932001-09-05 22:36:56 +00001496- The new C standard no longer requires that math libraries set errno to
1497 ERANGE on overflow. For platform libraries that exploit this new
1498 freedom, Python's overflow-checking was wholly broken. A new overflow-
1499 checking scheme attempts to repair that, but may not be reliable on all
1500 platforms (C doesn't seem to provide anything both useful and portable
1501 in this area anymore).
1502
Martin v. Löwis44f86962001-09-05 13:44:54 +00001503- Asynchronous timeout actions are available through the new class
1504 threading.Timer.
1505
Tim Peters78526162001-09-05 00:53:45 +00001506- math.log and math.log10 now return sensible results for even huge
1507 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1508
Tim Petersbdee63f2001-09-02 03:40:59 +00001509- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001510 currently held. See the docs for the imp module.
1511
Tim Petersbdee63f2001-09-02 03:40:59 +00001512- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001513 dumps containing ints written on platforms where Python ints are 8 bytes.
1514 When read on a box where Python ints are 4 bytes, such values are
1515 converted to Python longs.
1516
Tim Petersbdee63f2001-09-02 03:40:59 +00001517- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001518 code objects is no longer allowed. This plugs a security hole.
1519
Steve Purcell6091cd62001-09-06 16:05:17 +00001520- unittest.TestResult instances no longer store references to tracebacks
1521 generated by test failures. This prevents unexpected dangling references
1522 to objects that should be garbage collected between tests.
1523
Tim Petersedc99312001-08-22 21:36:50 +00001524Tools
1525
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001526- Tools/scripts/fixdiv.py has been added which can be used to fix
1527 division operators as per PEP 238.
1528
Tim Petersedc99312001-08-22 21:36:50 +00001529Build
1530
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001531- If you are an adventurous person using Mac OS X you may want to look at
1532 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1533 application, which can be used for experimenting with Carbon or Cocoa.
1534 Discussion of this on pythonmac-sig, please.
1535
Tim Peters7eea37e2001-09-04 22:08:56 +00001536C API
1537
1538- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001539
Tim Peters9fffa3e2001-09-04 05:14:19 +00001540- Note that PyLong_AsDouble can fail! This has always been true, but no
1541 callers checked for it. It's more likely to fail now, because overflow
1542 errors are properly detected now. The proper way to check:
1543
1544 double x = PyLong_AsDouble(some_long_object);
1545 if (x == -1.0 && PyErr_Occurred()) {
1546 /* The conversion failed. */
1547 }
1548
Tim Petersbdee63f2001-09-02 03:40:59 +00001549- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001550 compile but will not participate in GC. To upgrade an extension
1551 module:
1552
1553 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001554
Neil Schemenauer4042c692001-08-30 15:38:01 +00001555 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1556 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001557
Neil Schemenauer4042c692001-08-30 15:38:01 +00001558 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1559 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001560
Neil Schemenauer4042c692001-08-30 15:38:01 +00001561 - remove PyGC_HEAD_SIZE from object size calculations
1562
1563 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1564
Tim Petersbdee63f2001-09-02 03:40:59 +00001565- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001566 These can be used safely to construct string objects from a
1567 sprintf-style format string (similar to the format string supported
1568 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001569
Tim Petersedc99312001-08-22 21:36:50 +00001570New platforms
1571
Tim Petersb7da0902001-09-02 23:01:43 +00001572- Stephen Hansen contributed patches sufficient to get a clean compile
1573 under Borland C (Windows), but he reports problems running it and ran
1574 out of time to complete the port. Volunteers? Expect a MemoryError
1575 when importing the types module; this is probably shallow, and
1576 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001577
Tim Petersedc99312001-08-22 21:36:50 +00001578Tests
1579
1580Windows
1581
Tim Peters6e13a562001-09-06 00:32:15 +00001582- Large file support is now enabled on Win32 platforms as well as on
1583 Win64. This means that, for example, you can use f.tell() and f.seek()
1584 to manipulate files larger than 2 gigabytes (provided you have enough
1585 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001586 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1587 filesize limit, and large file support makes no difference there.
1588 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1589 NTFS has no practical limit on file size, and files of any size can be
1590 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001591
Tim Petersbdee63f2001-09-02 03:40:59 +00001592- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001593 points to command.com (patch from Brian Quinlan).
1594
Tim Petersedc99312001-08-22 21:36:50 +00001595
Tim Peters20f51a72001-07-21 02:31:40 +00001596What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001597Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001598===========================
1599
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001600Build
1601
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001602- Tim Peters developed a brand new Windows installer using Wise 8.1,
1603 generously donated to us by Wise Solutions.
1604
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001605- configure supports a new option --enable-unicode, with the values
1606 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1607 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001608
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001609- A new configure option --enable-framework builds a Mac OS X framework,
1610 which "make frameworkinstall" will install. This provides a starting
1611 point for more mac-like functionality, join pythonmac-sig@python.org
1612 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001613
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001614- The NeXT platform is no longer supported.
1615
1616- The `new' module is now statically linked.
1617
Tim Peters0afb6092001-08-15 06:06:44 +00001618Tools
1619
1620- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001621 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001622 the module docstring for details.
1623
Tim Peters20f51a72001-07-21 02:31:40 +00001624Tests
1625
Tim Peters5e824c32001-08-12 22:25:01 +00001626- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001627 platforms, allowing to give clearer test result output. regrtest
1628 also has optional --use/-u switch to run normally disabled tests
1629 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001630
Tim Peters20f51a72001-07-21 02:31:40 +00001631- Several new tests in the standard test suite, with special thanks to
1632 Nick Mathewson.
1633
1634Core
1635
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001636- The floor division operator // has been added as outlined in PEP
1637 238. The / operator still provides classic division (and will until
1638 Python 3.0) unless "from __future__ import division" is included, in
1639 which case the / operator will provide true division. The operator
1640 module provides truediv() and floordiv() functions. Augmented
1641 assignment variants are included, as are the equivalent overloadable
1642 methods and C API methods. See the PEP for a full discussion:
1643 <http://python.sf.net/peps/pep-0238.html>
1644
Tim Peters6cd6a822001-08-17 22:11:27 +00001645- Future statements are now effective in simulated interactive shells
1646 (like IDLE). This should "just work" by magic, but read Michael
1647 Hudson's "Future statements in simulated shells" PEP 264 for full
1648 details: <http://python.sf.net/peps/pep-0264.html>.
1649
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001650- The type/class unification (PEP 252-253) was integrated into the
1651 trunk and is not so tentative any more (the exact specification of
1652 some features is still tentative). A lot of work has done on fixing
1653 bugs and adding robustness and features (performance still has to
1654 come a long way).
1655
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001656- Warnings about a mismatch in the Python API during extension import
1657 now use the Python warning framework (which makes it possible to
1658 write filters for these warnings).
1659
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001660- A function's __dict__ (aka func_dict) will now always be a
1661 dictionary. It used to be possible to delete it or set it to None,
1662 but now both actions raise TypeErrors. It is still legal to set it
1663 to a dictionary object. Getting func.__dict__ before any attributes
1664 have been assigned now returns an empty dictionary instead of None.
1665
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001666- A new command line option, -E, was added which disables the use of
1667 all environment variables, or at least those that are specifically
1668 significant to Python. Usually those have a name starting with
1669 "PYTHON". This was used to fix a problem where the tests fail if
1670 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1671 older distribution.
1672
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001673Library
1674
Tim Peters5e824c32001-08-12 22:25:01 +00001675- New class Differ and new functions ndiff() and restore() in difflib.py.
1676 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001677 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001678
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001679- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1680 value using the minimal quoting required for the value; more
1681 reliable than using xml.sax.saxutils.escape() for attribute values.
1682
1683- Readline completion support for cmd.Cmd was added.
1684
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001685- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1686
1687- Added function threading.BoundedSemaphore()
1688
1689- Added Ka-Ping Yee's cgitb.py module.
1690
1691- The `new' module now exposes the CO_xxx flags.
1692
Martin v. Löwis560da622001-11-24 09:24:51 +00001693- The gc module offers the get_referents function.
1694
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001695New platforms
1696
1697C API
1698
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001699- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1700 which provide a cross-platform implementations for the
1701 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1702 the standard sprintf() and vsprintf() C lib APIs, these versions
1703 apply bounds checking on the used buffer which enhances protection
1704 against buffer overruns.
1705
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001706- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001707 and extensions using different Unicode widths is rendered next to
1708 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001709 will result in an ImportError. Unicode extensions writers must make
1710 sure to check the Unicode width compatibility in their extensions by
1711 using at least one of the mangled Unicode APIs in the extension.
1712
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001713- Two new flags METH_NOARGS and METH_O are available in method definition
1714 tables to simplify implementation of methods with no arguments and a
1715 single untyped argument. Calling such methods is more efficient than
1716 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1717 deprecated.
1718
Tim Petersc1731372001-08-04 08:12:36 +00001719Windows
1720
1721- "import module" now compiles module.pyw if it exists and nothing else
1722 relevant is found.
1723
Tim Peters20f51a72001-07-21 02:31:40 +00001724
Guido van Rossum55a78992001-07-17 17:22:32 +00001725What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001726Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001727===========================
1728
1729Core
Tim Petersa814db52001-05-14 07:05:58 +00001730
Tim Peters6d6c1a32001-08-02 04:15:00 +00001731- TENTATIVELY, a large amount of code implementing much of what's
1732 described in PEP 252 (Making Types Look More Like Classes) and PEP
1733 253 (Subtyping Built-in Types) was added. This will be released
1734 with Python 2.2a1. Documentation will be provided separately
1735 through http://www.python.org/2.2/. The purpose of releasing this
1736 with Python 2.2a1 is to test backwards compatibility. It is
1737 possible, though not likely, that a decision is made not to release
1738 this code as part of 2.2 final, if any serious backwards
1739 incompapatibilities are found during alpha testing that cannot be
1740 repaired.
1741
Guido van Rossum55a78992001-07-17 17:22:32 +00001742- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001743 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001744 more 'yield' statements. See PEP 255. Since this adds a new
1745 keyword to the language, this feature must be enabled by including a
1746 future statement: "from __future__ import generators" (see PEP 236).
1747 Generators will become a standard feature in a future release
1748 (probably 2.3). Without this future statement, 'yield' remains an
1749 ordinary identifier, but a warning is issued each time it is used.
1750 (These warnings currently don't conform to the warnings framework of
1751 PEP 230; we intend to fix this in 2.2a2.)
1752
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001753- The UTF-16 codec was modified to be more RFC compliant. It will now
1754 only remove BOM characters at the start of the string and then
1755 only if running in native mode (UTF-16-LE and -BE won't remove a
1756 leading BMO character).
1757
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001758- Strings now have a new method .decode() to complement the already
1759 existing .encode() method. These two methods provide direct access
1760 to the corresponding decoders and encoders of the registered codecs.
1761
1762 To enhance the usability of the .encode() method, the special
1763 casing of Unicode object return values was dropped (Unicode objects
1764 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001765
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001766 Both methods will now return whatever the codec in charge of the
1767 requested encoding returns as object, e.g. Unicode codecs will
1768 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1769 will return u"äöü"). This enables codec writer to create codecs
1770 for various simple to use conversions.
1771
1772 New codecs were added to demonstrate these new features (the .encode()
1773 and .decode() columns indicate the type of the returned objects):
1774
1775 Name | .encode() | .decode() | Description
1776 ----------------------------------------------------------------------
1777 uu | string | string | UU codec (e.g. for email)
1778 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001779 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001780 zlib | string | string | zlib compression
1781 hex | string | string | 2-byte hex codec
1782 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1783
Mark Hammond2a0af792001-05-14 03:09:36 +00001784- Some operating systems now support the concept of a default Unicode
1785 encoding for file system operations. Notably, Windows supports 'mbcs'
1786 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001787 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001788 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001789
1790 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001791 functions that return filenames (such as os.listdir()) to return Python
1792 string objects pre-encoded using the default file system encoding for
1793 the platform. As this encoding is likely to be different from Python's
1794 default encoding, converting this name to a Unicode object before passing
1795 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001796 would attempt to use its default encoding (generally ASCII) rather than
1797 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001798
Tim Petersa814db52001-05-14 07:05:58 +00001799 In general, this change simply removes surprises when working with
1800 Unicode and the file system, making these operations work as you expect,
1801 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001802 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001803
Tim Peters61dff2b2001-05-08 15:43:37 +00001804- Float (and complex) literals in source code were evaluated to full
1805 precision only when running from a .py file; the same code loaded from a
1806 .pyc (or .pyo) file could suffer numeric differences starting at about the
1807 12th significant decimal digit. For example, on a machine with IEEE-754
1808 floating arithmetic,
1809
1810 x = 9007199254740992.0
1811 print long(x)
1812
1813 printed 9007199254740992 if run directly from .py, but 9007199254740000
1814 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1815 str(float) instead of repr(float) when building code objects. marshal
1816 now uses repr(float) instead, which should reproduce floats to full
1817 machine precision (assuming the platform C float<->string I/O conversion
1818 functions are of good quality).
1819
1820 This may cause floating-point results to change in some cases, and
1821 usually for the better, but may also cause numerically unstable
1822 algorithms to break.
1823
Tim Peters2f228e72001-05-13 00:19:31 +00001824- The implementation of dicts suffers fewer collisions, which has speed
1825 benefits. However, the order in which dict entries appear in dict.keys(),
1826 dict.values() and dict.items() may differ from previous releases for a
1827 given dict. Nothing is defined about this order, so no program should
1828 rely on it. Nevertheless, it's easy to write test cases that rely on the
1829 order by accident, typically because of printing the str() or repr() of a
1830 dict to an "expected results" file. See Lib/test/test_support.py's new
1831 sortdict(dict) function for a simple way to display a dict in sorted
1832 order.
1833
Tim Peters7a3bfc32001-06-12 01:22:22 +00001834- Many other small changes to dicts were made, resulting in faster
1835 operation along the most common code paths.
1836
Guido van Rossum10315822001-05-01 20:54:30 +00001837- Dictionary objects now support the "in" operator: "x in dict" means
1838 the same as dict.has_key(x).
1839
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001840- The update() method of dictionaries now accepts generic mapping
1841 objects. Specifically the argument object must support the .keys()
1842 and __getitem__() methods. This allows you to say, for example,
1843 {}.update(UserDict())
1844
Guido van Rossum10315822001-05-01 20:54:30 +00001845- Iterators were added; this is a generalized way of providing values
1846 to a for loop. See PEP 234. There's a new built-in function iter()
1847 to return an iterator. There's a new protocol to get the next value
1848 from an iterator using the next() method (in Python) or the
1849 tp_iternext slot (in C). There's a new protocol to get iterators
1850 using the __iter__() method (in Python) or the tp_iter slot (in C).
1851 Iterating (i.e. a for loop) over a dictionary generates its keys.
1852 Iterating over a file generates its lines.
1853
Tim Petersf553f892001-05-01 20:45:31 +00001854- The following functions were generalized to work nicely with iterator
1855 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001856 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001857 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1858 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001859 join() method of strings
1860 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001861 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1862 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001863 right-hand side of assignment statements with multiple targets, such as
1864 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001865
Tim Petersd85e1022001-05-11 21:51:48 +00001866- Accessing module attributes is significantly faster (for example,
1867 random.random or os.path or yourPythonModule.yourAttribute).
1868
Tim Peterse63415e2001-05-08 04:38:29 +00001869- Comparing dictionary objects via == and != is faster, and now works even
1870 if the keys and values don't support comparisons other than ==.
1871
Tim Peters95bf9392001-05-10 08:32:44 +00001872- Comparing dictionaries in ways other than == and != is slower: there were
1873 insecurities in the dict comparison implementation that could cause Python
1874 to crash if the element comparison routines for the dict keys and/or
1875 values mutated the dicts. Making the code bulletproof slowed it down.
1876
Tim Peterseb28ef22001-06-02 05:27:19 +00001877- Collisions in dicts are resolved via a new approach, which can help
1878 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001879 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001880 faster now. Thanks to Christian Tismer for pointing out the cause and
1881 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001882
Tim Peters52e155e2001-06-16 05:42:57 +00001883- repr() is much faster for large containers (dict, list, tuple).
1884
1885
Tim Petersa814db52001-05-14 07:05:58 +00001886Library
1887
Fred Drake960fdf92001-07-20 18:38:26 +00001888- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1889 were added to the string module. These a locale-indenpendent
1890 constants, unlike letters, lowercase, and uppercase. These are now
1891 use in appropriate locations in the standard library.
1892
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001893- The flags used in dlopen calls can now be configured using
1894 sys.setdlopenflags and queried using sys.getdlopenflags.
1895
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001896- Fredrik Lundh's xmlrpclib is now a standard library module. This
1897 provides full client-side XML-RPC support. In addition,
1898 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1899 one asyncore-based). Thanks to Eric Raymond for the documentation.
1900
Guido van Rossum643d3912001-07-05 14:46:25 +00001901- The xrange() object is simplified: it no longer supports slicing,
1902 repetition, comparisons, efficient 'in' checking, the tolist()
1903 method, or the start, stop and step attributes. See PEP 260.
1904
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001905- A new function fnmatch.filter to filter lists of file names was added.
1906
Barry Warsawffd674d2001-05-22 16:00:10 +00001907- calendar.py uses month and day names based on the current locale.
1908
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001909- strop is now *really* obsolete (this was announced before with 1.6),
1910 and issues DeprecationWarning when used (except for the four items
1911 that are still imported into string.py).
1912
Tim Petersa814db52001-05-14 07:05:58 +00001913- Cookie.py now sorts key+value pairs by key in output strings.
1914
1915- pprint.isrecursive(object) didn't correctly identify recursive objects.
1916 Now it does.
1917
Tim Peters95b3f782001-05-14 18:39:41 +00001918- pprint functions now much faster for large containers (tuple, list, dict).
1919
Tim Peters7b9542a2001-06-10 23:40:19 +00001920- New 'q' and 'Q' format codes in the struct module, corresponding to C
1921 types "long long" and "unsigned long long" (on Windows, __int64). In
1922 native mode, these can be used only when the platform C compiler supports
1923 these types (when HAVE_LONG_LONG is #define'd by the Python config
1924 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001925 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1926 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001927
Guido van Rossum83213cc2001-06-12 16:48:52 +00001928- The site module installs a new built-in function 'help' that invokes
1929 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1930 it displays a message reminding the user to use 'help()' or
1931 'help(object)'.
1932
Tim Petersa814db52001-05-14 07:05:58 +00001933Tests
1934
1935- New test_mutants.py runs dict comparisons where the key and value
1936 comparison operators mutute the dicts randomly during comparison. This
1937 rapidly causes Python to crash under earlier releases (not for the faint
1938 of heart: it can also cause Win9x to freeze or reboot!).
1939
1940- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001941 pprint.isreadable() return sensible results. Also verifies that simple
1942 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001943
Tim Peters4324aa32001-05-28 22:30:08 +00001944C API
1945
1946- Removed the unused last_is_sticky argument from the internal
1947 _PyTuple_Resize(). If this affects you, you were cheating.
1948
1949
Guido van Rossum55a78992001-07-17 17:22:32 +00001950======================================================================
1951
1952
Guido van Rossumffe13be2001-04-16 18:46:45 +00001953What's New in Python 2.1 (final)?
1954=================================
1955
1956We only changed a few things since the last release candidate, all in
1957Python library code:
1958
1959- A bug in the locale module was fixed that affected locales which
1960 define no grouping for numeric formatting.
1961
1962- A few bugs in the weakref module's implementations of weak
1963 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1964 and the test suite was updated to check for these bugs.
1965
1966- An old bug in the os.path.walk() function (introduced in Python
1967 2.0!) was fixed: a non-existent file would cause an exception
1968 instead of being ignored.
1969
1970- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1971 PyChecker.
1972
1973
Guido van Rossum5b08f132001-04-16 02:05:23 +00001974What's New in Python 2.1c2?
1975===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001976
Guido van Rossum5b08f132001-04-16 02:05:23 +00001977A flurry of small changes, and one showstopper fixed in the nick of
1978time made it necessary to release another release candidate. The list
1979here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001980
Guido van Rossum5b08f132001-04-16 02:05:23 +00001981Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001982
Guido van Rossum5b08f132001-04-16 02:05:23 +00001983- Tim discovered a nasty bug in the dictionary code, caused by
1984 PyDict_Next() calling dict_resize(), and the GC code's use of
1985 PyDict_Next() violating an assumption in dict_items(). This was
1986 fixed with considerable amounts of band-aid, but the net effect is a
1987 saner and more robust implementation.
1988
1989- Made a bunch of symbols static that were accidentally global.
1990
1991Build and Ports
1992
1993- The setup.py script didn't check for a new enough version of zlib
1994 (1.1.3 is needed). Now it does.
1995
1996- Changed "make clean" target to also remove shared libraries.
1997
1998- Added a more general warning about the SGI Irix optimizer to README.
1999
2000Library
2001
2002- Fix a bug in urllib.basejoin("http://host", "../file.html") which
2003 omitted the slash between host and file.html.
2004
2005- The mailbox module's _Mailbox class contained a completely broken
2006 and undocumented seek() method. Ripped it out.
2007
2008- Fixed a bunch of typos in various library modules (urllib2, smtpd,
2009 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
2010
2011- Fixed a few last-minute bugs in unittest.
2012
2013Extensions
2014
2015- Reverted the patch to the OpenSSL code in socketmodule.c to support
2016 RAND_status() and the EGD, and the subsequent patch that tried to
2017 fix it for pre-0.9.5 versions; the problem with the patch is that on
2018 some systems it issues a warning whenever socket is imported, and
2019 that's unacceptable.
2020
2021Tests
2022
2023- Fixed the pickle tests to work with "import test.test_pickle".
2024
2025- Tweaked test_locale.py to actually run the test Windows.
2026
2027- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
2028 not "wb" (which is not a valid mode at all).
2029
2030- Fix pstats browser crashes. Import readline if it exists to make
2031 the user interface nicer.
2032
2033- Add "import thread" to the top of test modules that import the
2034 threading module (test_asynchat and test_threadedtempfile). This
2035 prevents test failures caused by a broken threading module resulting
2036 from a previously caught failed import.
2037
2038- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
2039 needed on some platforms (e.g. Solaris 8) when the tests are run
2040 twice in succession.
2041
2042- Skip rather than fail test_sunaudiodev if no audio device is found.
2043
2044
2045What's New in Python 2.1c1?
2046===========================
2047
2048This list was significantly updated when 2.1c2 was released; the 2.1c1
2049release didn't mention most changes that were actually part of 2.1c1:
2050
2051Legal
2052
2053- Copyright was assigned to the Python Software Foundation (PSF) and a
2054 PSF license (very similar to the CNRI license) was added.
2055
2056- The CNRI copyright notice was updated to include 2001.
2057
2058Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00002059
Guido van Rossumc9932722001-04-12 02:31:27 +00002060- After a public outcry, assignment to __debug__ is no longer illegal;
2061 instead, a warning is issued. It will become illegal in 2.2.
2062
Guido van Rossum5b08f132001-04-16 02:05:23 +00002063- Fixed a core dump with "%#x" % 0, and changed the semantics so that
2064 "%#x" now always prepends "0x", even if the value is zero.
2065
2066- Fixed some nits in the bytecode compiler.
2067
2068- Fixed core dumps when calling certain kinds of non-functions.
2069
2070- Fixed various core dumps caused by reference count bugs.
2071
2072Build and Ports
2073
2074- Use INSTALL_SCRIPT to install script files.
2075
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002076- New port: SCO Unixware 7, by Billy G. Allie.
2077
Guido van Rossum5b08f132001-04-16 02:05:23 +00002078- Updated RISCOS port.
2079
2080- Updated BeOS port and notes.
2081
2082- Various other porting problems resolved.
2083
2084Library
2085
2086- The TERMIOS and SOCKET modules are now truly obsolete and
2087 unnecessary. Their symbols are incorporated in the termios and
2088 socket modules.
2089
2090- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
2091 better tests for pickling.
2092
2093- threading: make Condition.wait() robust against KeyboardInterrupt.
2094
2095- zipfile: add support to zipfile to support opening an archive
2096 represented by an open file rather than a file name. Fix bug where
2097 the archive was not properly closed. Fixed a bug in this bugfix
2098 where flush() was called for a read-only file.
2099
2100- imputil: added an uninstall() method to the ImportManager.
2101
2102- Canvas: fixed bugs in lower() and tkraise() methods.
2103
2104- SocketServer: API change (added overridable close_request() method)
2105 so that the TCP server can explicitly close the request.
2106
2107- pstats: Eric Raymond added a simple interactive statistics browser,
2108 invoked when the module is run as a script.
2109
2110- locale: fixed a problem in format().
2111
2112- webbrowser: made it work when the BROWSER environment variable has a
2113 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
2114 KDE 2. Fixed some other nits.
2115
2116- unittest: changes to allow using a different exception than
2117 AssertionError, and added a few more function aliases. Some other
2118 small changes.
2119
2120- urllib, urllib2: fixed redirect problems and a coupleof other nits.
2121
2122- asynchat: fixed a critical bug in asynchat that slipped through the
2123 2.1b2 release. Fixed another rare bug.
2124
2125- Fix some unqualified except: clauses (always a bad code example).
2126
2127XML
2128
2129- pyexpat: new API get_version_string().
2130
2131- Fixed some minidom bugs.
2132
2133Extensions
2134
2135- Fixed a core dump in _weakref. Removed the weakref.mapping()
2136 function (it adds nothing to the API).
2137
2138- Rationalized the use of header files in the readline module, to make
2139 it compile (albeit with some warnings) with the very recent readline
2140 4.2, without breaking for earlier versions.
2141
2142- Hopefully fixed a buffering problem in linuxaudiodev.
2143
2144- Attempted a fix to make the OpenSSL support in the socket module
2145 work again with pre-0.9.5 versions of OpenSSL.
2146
2147Tests
2148
2149- Added a test case for asynchat and asyncore.
2150
2151- Removed coupling between tests where one test failing could break
2152 another.
2153
2154Tools
2155
2156- Ping added an interactive help browser to pydoc, fixed some nits
2157 in the rest of the pydoc code, and added some features to his
2158 inspect module.
2159
2160- An updated python-mode.el version 4.1 which integrates Ken
2161 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
2162 much nicer in XEmacs and Emacs. When stepping through your program
2163 with pdb, in either the shell window or the *Python* window, the
2164 source file and line will be tracked by an arrow. Very cool!
2165
2166- IDLE: syntax warnings in interactive mode are changed into errors.
2167
2168- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00002169 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00002170
2171- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002172
Barry Warsaw11e89c72001-04-11 20:37:57 +00002173
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002174What's New in Python 2.1 beta 2?
2175================================
2176
Guido van Rossum053ae352001-03-22 14:17:21 +00002177(Unlisted are many fixed bugs, more documentation, etc.)
2178
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002179Core language, builtins, and interpreter
2180
Guido van Rossum053ae352001-03-22 14:17:21 +00002181- The nested scopes work (enabled by "from __future__ import
2182 nested_scopes") is completed; in particular, the future now extends
2183 into code executed through exec, eval() and execfile(), and into the
2184 interactive interpreter.
2185
2186- When calling a base class method (e.g. BaseClass.__init__(self)),
2187 this is now allowed even if self is not strictly spoken a class
2188 instance (e.g. when using metaclasses or the Don Beaudry hook).
2189
2190- Slice objects are now comparable but not hashable; this prevents
2191 dict[:] from being accepted but meaningless.
2192
2193- Complex division is now calculated using less braindead algorithms.
2194 This doesn't change semantics except it's more likely to give useful
2195 results in extreme cases. Complex repr() now uses full precision
2196 like float repr().
2197
2198- sgmllib.py now calls handle_decl() for simple <!...> declarations.
2199
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002200- It is illegal to assign to the name __debug__, which is set when the
2201 interpreter starts. It is effectively a compile-time constant.
2202
2203- A warning will be issued if a global statement for a variable
2204 follows a use or assignment of that variable.
2205
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002206Standard library
2207
Guido van Rossum053ae352001-03-22 14:17:21 +00002208- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
2209 inspired by JUnit), is now part of the standard library. You now
2210 have a choice of two testing frameworks: unittest requires you to
2211 write testcases as separate code, doctest gathers them from
2212 docstrings. Both approaches have their advantages and
2213 disadvantages.
2214
2215- A new module Tix was added, which wraps the Tix extension library
2216 for Tk. With that module, it is not necessary to statically link
2217 Tix with _tkinter, since Tix will be loaded with Tcl's "package
2218 require" command. See Demo/tix/.
2219
2220- tzparse.py is now obsolete.
2221
2222- In gzip.py, the seek() and tell() methods are removed -- they were
2223 non-functional anyway, and it's better if callers can test for their
2224 existence with hasattr().
2225
2226Python/C API
2227
2228- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
2229 that's already in the dictionary during a PyDict_Next() iteration.
2230 This used to fail occasionally when a dictionary resize operation
2231 could be triggered that would rehash all the keys. All other
2232 modifications to the dictionary are still off-limits during a
2233 PyDict_Next() iteration!
2234
2235- New extended APIs related to passing compiler variables around.
2236
2237- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
2238 implement isinstance() and issubclass().
2239
2240- Py_BuildValue() now has a "D" conversion to create a Python complex
2241 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002242
Fred Drake4e262a92001-03-22 18:26:47 +00002243- Extensions types which support weak references must now set the
2244 field allocated for the weak reference machinery to NULL themselves;
2245 this is done to avoid the cost of checking each object for having a
2246 weakly referencable type in PyObject_INIT(), since most types are
2247 not weakly referencable.
2248
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002249- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
2250 free variables and cell variables to and from the frame's f_locals.
2251
2252- Variants of several functions defined in pythonrun.h have been added
2253 to support the nested_scopes future statement. The variants all end
2254 in Flags and take an extra argument, a PyCompilerFlags *; examples:
2255 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
2256 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00002257 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002258
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002259Distutils
2260
2261- the sdist command now writes a PKG-INFO file, as described in PEP 241,
2262 into the release tree.
2263
Tim Peters0e57abf2001-05-02 07:39:38 +00002264- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002265 (an uninstaller, more customization of the installer's display)
2266
2267- from Jack Jansen: added Mac-specific code to generate a dialog for
2268 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00002269 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002270 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00002271
2272- added 'platforms' and 'keywords' to the set of metadata that can be
2273 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002274
2275- applied patches from Jason Tishler to make the compiler class work with
2276 Cygwin.
2277
2278
Tim Peters2fe289a2001-03-01 22:19:38 +00002279What's New in Python 2.1 beta 1?
2280================================
Tim Petersd66595f2001-02-04 03:09:53 +00002281
2282Core language, builtins, and interpreter
2283
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00002284- Following an outcry from the community about the amount of code
2285 broken by the nested scopes feature introduced in 2.1a2, we decided
2286 to make this feature optional, and to wait until Python 2.2 (or at
2287 least 6 months) to make it standard. The option can be enabled on a
2288 per-module basis by adding "from __future__ import nested_scopes" at
2289 the beginning of a module (before any other statements, but after
2290 comments and an optional docstring). See PEP 236 (Back to the
2291 __future__) for a description of the __future__ statement. PEP 227
2292 (Statically Nested Scopes) has been updated to reflect this change,
2293 and to clarify the semantics in a number of endcases.
2294
2295- The nested scopes code, when enabled, has been hardened, and most
2296 bugs and memory leaks in it have been fixed.
2297
2298- Compile-time warnings are now generated for a number of conditions
2299 that will break or change in meaning when nested scopes are enabled:
2300
2301 - Using "from...import *" or "exec" without in-clause in a function
2302 scope that also defines a lambda or nested function with one or
2303 more free (non-local) variables. The presence of the import* or
2304 bare exec makes it impossible for the compiler to determine the
2305 exact set of local variables in the outer scope, which makes it
2306 impossible to determine the bindings for free variables in the
2307 inner scope. To avoid the warning about import *, change it into
2308 an import of explicitly name object, or move the import* statement
2309 to the global scope; to avoid the warning about bare exec, use
2310 exec...in... (a good idea anyway -- there's a possibility that
2311 bare exec will be deprecated in the future).
2312
2313 - Use of a global variable in a nested scope with the same name as a
2314 local variable in a surrounding scope. This will change in
2315 meaning with nested scopes: the name in the inner scope will
2316 reference the variable in the outer scope rather than the global
2317 of the same name. To avoid the warning, either rename the outer
2318 variable, or use a global statement in the inner function.
2319
Neil Schemenauera35c6882001-02-27 04:45:05 +00002320- An optional object allocator has been included. This allocator is
2321 optimized for Python objects and should be faster and use less memory
2322 than the standard system allocator. It is not enabled by default
2323 because of possible thread safety problems. The allocator is only
2324 protected by the Python interpreter lock and it is possible that some
2325 extension modules require a thread safe allocator. The object
2326 allocator can be enabled by providing the "--with-pymalloc" option to
2327 configure.
2328
Tim Petersd66595f2001-02-04 03:09:53 +00002329Standard library
2330
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002331- pyexpat now detects the expat version if expat.h defines it. A
2332 number of additional handlers are provided, which are only available
2333 since expat 1.95. In addition, the methods SetParamEntityParsing and
2334 GetInputContext of Parser objects are available with 1.95.x
2335 only. Parser objects now provide the ordered_attributes and
2336 specified_attributes attributes. A new module expat.model was added,
2337 which offers a number of additional constants if 1.95.x is used.
2338
2339- xml.dom offers the new functions registerDOMImplementation and
2340 getDOMImplementation.
2341
2342- xml.dom.minidom offers a toprettyxml method. A number of DOM
2343 conformance issues have been resolved. In particular, Element now
2344 has an hasAttributes method, and the handling of namespaces was
2345 improved.
2346
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002347- Ka-Ping Yee contributed two new modules: inspect.py, a module for
2348 getting information about live Python code, and pydoc.py, a module
2349 for interactively converting docstrings to HTML or text.
2350 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002351 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002352 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2353 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002354
Tim Peters1eff7962001-03-01 02:31:33 +00002355- New library module difflib.py, primarily packaging the SequenceMatcher
2356 class at the heart of the popular ndiff.py file-comparison tool.
2357
2358- doctest.py (a framework for verifying Python code examples in docstrings)
2359 is now part of the std library.
2360
Tim Petersd66595f2001-02-04 03:09:53 +00002361Windows changes
2362
Guido van Rossume3955a82001-03-02 14:05:59 +00002363- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2364 small GUI that lets you browse the module docstrings using your
2365 default web browser.
2366
Tim Peters1eff7962001-03-01 02:31:33 +00002367- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2368 Platforms) is implemented. See
2369
2370 http://python.sourceforge.net/peps/pep-0235.html
2371
2372 for full details, especially the "Current Lower-Left Semantics" section.
2373 The new Windows import rules are simpler than before:
2374
2375 A. If the PYTHONCASEOK environment variable exists, same as
2376 before: silently accept the first case-insensitive match of any
2377 kind; raise ImportError if none found.
2378
2379 B. Else search sys.path for the first case-sensitive match; raise
2380 ImportError if none found.
2381
2382 The same rules have been implented on other platforms with case-
2383 insensitive but case-preserving filesystems too (including Cygwin, and
2384 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002385
Tim Peters25a9ce32001-02-19 07:06:36 +00002386- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2387 what it's supposed to do (and does do under NT and 2000) via direct
2388 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002389 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002390 all Win9x systems before.
2391
Tim Peters1eff7962001-03-01 02:31:33 +00002392- Build: Subproject _test (effectively) renamed to _testcapi.
2393
Tim Peters2fe289a2001-03-01 22:19:38 +00002394New platforms
2395
2396- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2397 Thanks to Steven Majewski!
2398
2399- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2400 Tishler!
2401
Guido van Rossum9089b272001-03-02 06:49:50 +00002402- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2403 Schwertberger! See RISCOS/README for more information -- it seems
2404 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002405 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002406
Tim Peters25a9ce32001-02-19 07:06:36 +00002407
Tim Petersd7b5e882001-01-25 03:36:26 +00002408What's New in Python 2.1 alpha 2?
2409=================================
Tim Peters40ead762001-01-27 05:35:26 +00002410
Tim Petersd7b5e882001-01-25 03:36:26 +00002411Core language, builtins, and interpreter
2412
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002413- Scopes nest. If a name is used in a function or class, but is not
2414 local, the definition in the nearest enclosing function scope will
2415 be used. One consequence of this change is that lambda statements
2416 could reference variables in the namespaces where the lambda is
2417 defined. In some unusual cases, this change will break code.
2418
2419 In all previous version of Python, names were resolved in exactly
2420 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002421 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002422 function A is defined within a function B, the names bound in B are
2423 not visible in A. The new rules make names bound in B visible in A,
2424 unless A contains a name binding that hides the binding in B.
2425
2426 Section 4.1 of the reference manual describes the new scoping rules
2427 in detail. The test script in Lib/test/test_scope.py demonstrates
2428 some of the effects of the change.
2429
2430 The new rules will cause existing code to break if it defines nested
2431 functions where an outer function has local variables with the same
2432 name as globals or builtins used by the inner function. Example:
2433
2434 def munge(str):
2435 def helper(x):
2436 return str(x)
2437 if type(str) != type(''):
2438 str = helper(str)
2439 return str.strip()
2440
2441 Under the old rules, the name str in helper() is bound to the
2442 builtin function str(). Under the new rules, it will be bound to
2443 the argument named str and an error will occur when helper() is
2444 called.
2445
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002446- The compiler will report a SyntaxError if "from ... import *" occurs
2447 in a function or class scope. The language reference has documented
2448 that this case is illegal, but the compiler never checked for it.
2449 The recent introduction of nested scope makes the meaning of this
2450 form of name binding ambiguous. In a future release, the compiler
2451 may allow this form when there is no possibility of ambiguity.
2452
Tim Peters40ead762001-01-27 05:35:26 +00002453- repr(string) is easier to read, now using hex escapes instead of octal,
2454 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2455
2456 >>> "\texample \r\n" + chr(0) + chr(255)
2457 '\texample \r\n\x00\xff' # in 2.1
2458 '\011example \015\012\000\377' # in 2.0
2459
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002460- Functions are now compared and hashed by identity, not by value, since
2461 the func_code attribute is writable.
2462
Fred Drakefb9d7122001-02-01 20:00:40 +00002463- Weak references (PEP 205) have been added. This involves a few
2464 changes in the core, an extension module (_weakref), and a Python
2465 module (weakref). The weakref module is the public interface. It
2466 includes support for "explicit" weak references, proxy objects, and
2467 mappings with weakly held values.
2468
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002469- A 'continue' statement can now appear in a try block within the body
2470 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002471 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002472
Tim Petersd7b5e882001-01-25 03:36:26 +00002473Standard library
2474
Barry Warsaw30dbd142001-01-31 22:14:01 +00002475- mailbox.py now has a new class, PortableUnixMailbox which is
2476 identical to UnixMailbox but uses a more portable scheme for
2477 determining From_ separators. Also, the constructors for all the
2478 classes in this module have a new optional `factory' argument, which
2479 is a callable used when new message classes must be instantiated by
2480 the next() method.
2481
Tim Petersd7b5e882001-01-25 03:36:26 +00002482- random.py is now self-contained, and offers all the functionality of
2483 the now-deprecated whrandom.py. See the docs for details. random.py
2484 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002485 and restoring the internal state of the generator; and jumpahead(n),
2486 for quickly forcing the internal state to be the same as if n calls to
2487 random() had been made. The latter is particularly useful for multi-
2488 threaded programs, creating one instance of the random.Random() class for
2489 each thread, then using .jumpahead() to force each instance to use a
2490 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002491
Tim Peters0de88fc2001-02-01 04:59:18 +00002492- random.py's seed() function is new. For bit-for-bit compatibility with
2493 prior releases, use the whseed function instead. The new seed function
2494 addresses two problems: (1) The old function couldn't produce more than
2495 about 2**24 distinct internal states; the new one about 2**45 (the best
2496 that can be done in the Wichmann-Hill generator). (2) The old function
2497 sometimes produced identical internal states when passed distinct
2498 integers, and there was no simple way to predict when that would happen;
2499 the new one guarantees to produce distinct internal states for all
2500 arguments in [0, 27814431486576L).
2501
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002502- The socket module now supports raw packets on Linux. The socket
2503 family is AF_PACKET.
2504
Tim Peters9ea17ac2001-02-02 05:57:15 +00002505- test_capi.py is a start at running tests of the Python C API. The tests
2506 are implemented by the new Modules/_testmodule.c.
2507
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002508- A new extension module, _symtable, provides provisional access to the
2509 internal symbol table used by the Python compiler. A higher-level
2510 interface will be added on top of _symtable in a future release.
2511
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002512- Removed the obsolete soundex module.
2513
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002514- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2515 the isSameNode method; NamedNodeMap the get method.
2516
2517- xml.sax.expatreader supports the lexical handler property; it
2518 generates comment, startCDATA, and endCDATA events.
2519
Tim Petersee826f82001-01-31 19:39:44 +00002520Windows changes
2521
2522- Build procedure: the zlib project is built in a different way that
2523 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002524 the zlib binary used. See PCbuild\readme.txt for details. Your old
2525 zlib-related directories can be deleted; you'll need to download fresh
2526 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002527
Tim Peters9ea17ac2001-02-02 05:57:15 +00002528- Build: New subproject _test for the benefit of test_capi.py (see above).
2529
Tim Petersb16c56f2001-02-02 21:24:51 +00002530- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2531 interface to some Python compiler internals).
2532
2533- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002534 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002535
Tim Petersa3a3a032000-11-30 05:22:44 +00002536What's New in Python 2.1 alpha 1?
2537=================================
2538
2539Core language, builtins, and interpreter
2540
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002541- There is a new Unicode companion to the PyObject_Str() API
2542 called PyObject_Unicode(). It behaves in the same way as the
2543 former, but assures that the returned value is an Unicode object
2544 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002545
Guido van Rossumf98eda02001-01-17 15:54:45 +00002546- The comparison operators support "rich comparison overloading" (PEP
2547 207). C extension types can provide a rich comparison function in
2548 the new tp_richcompare slot in the type object. The cmp() function
2549 and the C function PyObject_Compare() first try the new rich
2550 comparison operators before trying the old 3-way comparison. There
2551 is also a new C API PyObject_RichCompare() (which also falls back on
2552 the old 3-way comparison, but does not constrain the outcome of the
2553 rich comparison to a Boolean result).
2554
2555 The rich comparison function takes two objects (at least one of
2556 which is guaranteed to have the type that provided the function) and
2557 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2558 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2559 object, which may be NotImplemented (in which case the tp_compare
2560 slot function is used as a fallback, if defined).
2561
2562 Classes can overload individual comparison operators by defining one
2563 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002564 __ge__. There are no explicit "reflected argument" versions of
2565 these; instead, __lt__ and __gt__ are each other's reflection,
2566 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2567 reflection (similar at the C level). No other implications are
2568 made; in particular, Python does not assume that == is the Boolean
2569 inverse of !=, or that < is the Boolean inverse of >=. This makes
2570 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002571
2572 Classes or types that want to implement (in)equality tests but not
2573 the ordering operators (i.e. unordered types) should implement ==
2574 and !=, and raise an error for the ordering operators.
2575
Guido van Rossuma88479f2001-01-18 14:28:08 +00002576 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002577 Boolean; e.g. a matrix type might want to return a matrix of bits
2578 for A < B, giving elementwise comparisons. Such types should ensure
2579 that any interpretation of their value in a Boolean context raises
2580 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2581 at the C level) to always raise an exception.
2582
Guido van Rossuma88479f2001-01-18 14:28:08 +00002583- Complex numbers use rich comparisons to define == and != but raise
2584 an exception for <, <=, > and >=. Unfortunately, this also means
2585 that cmp() of two complex numbers raises an exception when the two
2586 numbers differ. Since it is not mathematically meaningful to compare
2587 complex numbers except for equality, I hope that this doesn't break
2588 too much code.
2589
Tim Peters3389f192001-02-18 08:48:49 +00002590- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002591 not defined by the language, other than that it's arbitrary but
2592 consistent (see the Reference Manual). An implementation detail changed
2593 in 2.1a1 such that None now compares less than any other object. Code
2594 relying on this new behavior (like code that relied on the previous
2595 behavior) does so at its own risk.
2596
Barry Warsaw573b5412001-01-15 20:43:18 +00002597- Functions and methods now support getting and setting arbitrarily
2598 named attributes (PEP 232). Functions have a new __dict__
2599 (a.k.a. func_dict) which hold the function attributes. Methods get
2600 and set attributes on their underlying im_func. It is a TypeError
2601 to set an attribute on a bound method.
2602
Guido van Rossum051e3352001-01-15 19:11:10 +00002603- The xrange() object implementation has been improved so that
2604 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2605 limitation that in this case len(xrange(sys.maxint)) can't be
2606 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2607 work fine as long as the index i doesn't actually reach 2**31.
2608 (Python uses regular ints for sequence and string indices; fixing
2609 that is much more work.)
2610
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002611- Two changes to from...import:
2612
Guido van Rossumba381232001-02-03 15:06:40 +00002613 1) "from M import X" now works even if (after loading module M)
2614 sys.modules['M'] is not a real module; it's basically a getattr()
2615 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002616
2617 2) "from M import *" now looks for M.__all__ to decide which names to
2618 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2619 filters out names starting with '_' as before. Whether or not
2620 __all__ exists, there's no restriction on the type of M.
2621
Guido van Rossumf61f1662001-01-10 20:13:55 +00002622- File objects have a new method, xreadlines(). This is the fastest
2623 way to iterate over all lines in a file:
2624
2625 for line in file.xreadlines():
2626 ...do something to line...
2627
2628 See the xreadlines module (mentioned below) for how to do this for
2629 other file-like objects.
2630
2631- Even if you don't use file.xreadlines(), you may expect a speedup on
2632 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002633 quite a bit in platform-specific ways: on systems (like Linux) that
2634 support flockfile(), getc_unlocked(), and funlockfile(), those are
2635 used by default. On systems (like Windows) without getc_unlocked(),
2636 a complicated (but still thread-safe) method using fgets() is used by
2637 default.
2638
Tim Petersd52269b2001-01-25 06:23:18 +00002639 You can force use of the fgets() method by #define'ing
2640 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002641 getc_unlocked()).
2642
Tim Petersd52269b2001-01-25 06:23:18 +00002643 You can force fgets() not to be used by #define'ing
2644 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002645 test_bufio.py fails -- and let us know if it does!).
2646
2647- In addition, the fileinput module, while still slower than the other
2648 methods on most platforms, has been sped up too, by using
2649 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002650
2651- Support for run-time warnings has been added, including a new
2652 command line option (-W) to specify the disposition of warnings.
2653 See the description of the warnings module below.
2654
2655- Extensive changes have been made to the coercion code. This mostly
2656 affects extension modules (which can now implement mixed-type
2657 numerical operators without having to use coercion), but
2658 occasionally, in boundary cases the coercion semantics have changed
2659 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002660 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002661 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002662 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002663
Guido van Rossumf98eda02001-01-17 15:54:45 +00002664- In connection with the coercion changes, a new built-in singleton
2665 object, NotImplemented is defined. This can be returned for
2666 operations that wish to indicate they are not implemented for a
2667 particular combination of arguments. From C, this is
2668 Py_NotImplemented.
2669
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002670- The interpreter accepts now bytecode files on the command line even
2671 if they do not have a .pyc or .pyo extension. On Linux, after executing
2672
Martin v. Löwise214baa2001-02-04 22:37:56 +00002673import imp,sys,string
2674magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2675reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2676open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002677
2678 any byte code file can be used as an executable (i.e. as an argument
2679 to execve(2)).
2680
Tim Peters9940b802000-12-01 07:59:35 +00002681- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002682 character. In 1.6 and earlier, they never produced a sign,
2683 and raised an error if the value of the long was too large
2684 to fit in a Python int. In 2.0, they produced a sign if and
2685 only if too large to fit in an int. This was inconsistent
2686 across platforms (because the size of an int varies across
2687 platforms), and inconsistent with hex() and oct(). Example:
2688
2689 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002690 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002691 'ffffffbe' # in 2.0 and before, on 32-bit machines
2692 >>> hex(-0x42L)
2693 '-0x42L' # in all versions of Python
2694
Tim Peters9940b802000-12-01 07:59:35 +00002695 The behavior of %d formats for negative Python longs remains
2696 the same as in 2.0 (although in 1.6 and before, they raised
2697 an error if the long didn't fit in a Python int).
2698
2699 %u formats don't make sense for Python longs, but are allowed
2700 and treated the same as %d in 2.1. In 2.0, a negative long
2701 formatted via %u produced a sign if and only if too large to
2702 fit in an int. In 1.6 and earlier, a negative long formatted
2703 via %u raised an error if it was too big to fit in an int.
2704
Guido van Rossum3661d392000-12-12 22:10:31 +00002705- Dictionary objects have an odd new method, popitem(). This removes
2706 an arbitrary item from the dictionary and returns it (in the form of
2707 a (key, value) pair). This can be useful for algorithms that use a
2708 dictionary as a bag of "to do" items and repeatedly need to pick one
2709 item. Such algorithms normally end up running in quadratic time;
2710 using popitem() they can usually be made to run in linear time.
2711
Tim Peters36cdad12000-12-29 02:06:45 +00002712Standard library
2713
Thomas Woutersfe385252001-01-19 23:16:56 +00002714- In the time module, the time argument to the functions strftime,
2715 localtime, gmtime, asctime and ctime is now optional, defaulting to
2716 the current time (in the local timezone).
2717
Guido van Rossumda91f222001-01-15 16:36:08 +00002718- The ftplib module now defaults to passive mode, which is deemed a
2719 more useful default given that clients are often inside firewalls
2720 these days. Note that this could break if ftplib is used to connect
2721 to a *server* that is inside a firewall, from outside; this is
2722 expected to be a very rare situation. To fix that, you can call
2723 ftp.set_pasv(0).
2724
Martin v. Löwis10a27872001-01-13 09:54:41 +00002725- The module site now treats .pth files not only for path configuration,
2726 but also supports extensions to the initialization code: Lines starting
2727 with import are executed.
2728
Guido van Rossumf61f1662001-01-10 20:13:55 +00002729- There's a new module, warnings, which implements a mechanism for
2730 issuing and filtering warnings. There are some new built-in
2731 exceptions that serve as warning categories, and a new command line
2732 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2733 turns warnings into errors). warnings.warn(message[, category])
2734 issues a warning message; this can also be called from C as
2735 PyErr_Warn(category, message).
2736
2737- A new module xreadlines was added. This exports a single factory
2738 function, xreadlines(). The intention is that this code is the
2739 absolutely fastest way to iterate over all lines in an open
2740 file(-like) object:
2741
2742 import xreadlines
2743 for line in xreadlines.xreadlines(file):
2744 ...do something to line...
2745
2746 This is equivalent to the previous the speed record holder using
2747 file.readlines(sizehint). Note that if file is a real file object
2748 (as opposed to a file-like object), this is equivalent:
2749
2750 for line in file.xreadlines():
2751 ...do something to line...
2752
Tim Peters36cdad12000-12-29 02:06:45 +00002753- The bisect module has new functions bisect_left, insort_left,
2754 bisect_right and insort_right. The old names bisect and insort
2755 are now aliases for bisect_right and insort_right. XXX_right
2756 and XXX_left methods differ in what happens when the new element
2757 compares equal to one or more elements already in the list: the
2758 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002759 right. Code that doesn't care where equal elements end up should
2760 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002761
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002762- The new curses.panel module wraps the panel library that forms part
2763 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2764
Guido van Rossumf61f1662001-01-10 20:13:55 +00002765- The SocketServer module now sets the allow_reuse_address flag by
2766 default in the TCPServer class.
2767
2768- A new function, sys._getframe(), returns the stack frame pointer of
2769 the caller. This is intended only as a building block for
2770 higher-level mechanisms such as string interpolation.
2771
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002772- The pyexpat module supports a number of new handlers, which are
2773 available only in expat 1.2. If invocation of a callback fails, it
2774 will report an additional frame in the traceback. Parser objects
2775 participate now in garbage collection. If expat reports an unknown
2776 encoding, pyexpat will try to use a Python codec; that works only
2777 for single-byte charsets. The parser type objects is exposed as
2778 XMLParserObject.
2779
2780- xml.dom now offers standard definitions for symbolic node type and
2781 exception code constants, and a hierarchy of DOM exceptions. minidom
2782 was adjusted to use them.
2783
2784- The conformance of xml.dom.minidom to the DOM specification was
2785 improved. It detects a number of additional error cases; the
2786 previous/next relationship works even when the tree is modified;
2787 Node supports the normalize() method; NamedNodeMap, DocumentType and
2788 DOMImplementation classes were added; Element supports the
2789 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2790 method.
2791
Guido van Rossumf61f1662001-01-10 20:13:55 +00002792Build issues
2793
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002794- For Unix (and Unix-compatible) builds, configuration and building of
2795 extension modules is now greatly automated. Rather than having to
2796 edit the Modules/Setup file to indicate which modules should be
2797 built and where their include files and libraries are, a
2798 distutils-based setup.py script now takes care of building most
2799 extension modules. All extension modules built this way are built
2800 as shared libraries. Only a few modules that must be linked
2801 statically are still listed in the Setup file; you won't need to
2802 edit their configuration.
2803
2804- Python should now build out of the box on Cygwin. If it doesn't,
2805 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002806
2807- Python now always uses its own (renamed) implementation of getopt()
2808 -- there's too much variation among C library getopt()
2809 implementations.
2810
2811- C++ compilers are better supported; the CXX macro is always set to a
2812 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002813
Tim Petersd92dfe02000-12-12 01:18:41 +00002814Windows changes
2815
2816- select module: By default under Windows, a select() call
2817 can specify no more than 64 sockets. Python now boosts
2818 this Microsoft default to 512. If you need even more than
2819 that, see the MS docs (you'll need to #define FD_SETSIZE
2820 and recompile Python from source).
2821
Guido van Rossumf61f1662001-01-10 20:13:55 +00002822- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2823 subdirectory is no more!
2824
Tim Petersa3a3a032000-11-30 05:22:44 +00002825
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002826What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002827=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002828
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002829Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002830changes are in the file HISTORY. If you are making the jump directly
2831from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2832HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002833
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002834Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2835the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2836http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002837
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002838--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002839
2840======================================================================
2841
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002842What's new in 2.0 (since release candidate 1)?
2843==============================================
2844
2845Standard library
2846
2847- The copy_reg module was modified to clarify its intended use: to
2848 register pickle support for extension types, not for classes.
2849 pickle() will raise a TypeError if it is passed a class.
2850
2851- Fixed a bug in gettext's "normalize and expand" code that prevented
2852 it from finding an existing .mo file.
2853
2854- Restored support for HTTP/0.9 servers in httplib.
2855
Tim Peters989b7b92000-10-16 20:24:53 +00002856- The math module was changed to stop raising OverflowError in case of
2857 underflow, and return 0 instead in underflow cases. Whether Python
2858 used to raise OverflowError in case of underflow was platform-
2859 dependent (it did when the platform math library set errno to ERANGE
2860 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002861
2862- Fixed a bug in StringIO that occurred when the file position was not
2863 at the end of the file and write() was called with enough data to
2864 extend past the end of the file.
2865
2866- Fixed a bug that caused Tkinter error messages to get lost on
2867 Windows. The bug was fixed by replacing direct use of
2868 interp->result with Tcl_GetStringResult(interp).
2869
2870- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2871 redirect response.
2872
2873- Several changes were made to distutils: Some debugging code was
2874 removed from util. Fixed the installer used when an external zip
2875 program (like WinZip) is not found; the source code for this
2876 installer is in Misc/distutils. check_lib() was modified to behave
2877 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2878 test for whether installed modules are on sys.path was changed to
2879 use both normcase() and normpath().
2880
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002881- Several minor bugs were fixed in the xml package (the minidom,
2882 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002883
2884- The regression test driver (regrtest.py) behavior when invoked with
2885 -l changed: It now reports a count of objects that are recognized as
2886 garbage but not freed by the garbage collector.
2887
Tim Peters989b7b92000-10-16 20:24:53 +00002888- The regression test for the math module was changed to test
2889 exceptional behavior when the test is run in verbose mode. Python
2890 cannot yet guarantee consistent exception behavior across platforms,
2891 so the exception part of test_math is run only in verbose mode, and
2892 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002893
2894Internals
2895
2896- PyOS_CheckStack() has been disabled on Win64, where it caused
2897 test_sre to fail.
2898
2899Build issues
2900
2901- Changed compiler flags, so that gcc is always invoked with -Wall and
2902 -Wstrict-prototypes. Users compiling Python with GCC should see
2903 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002904 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002905 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002906
Tim Petersa3a3a032000-11-30 05:22:44 +00002907- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002908
2909Tools and other miscellany
2910
2911- The compiler in Tools/compiler was updated to support the new
2912 language features introduced in 2.0: extended print statement, list
2913 comprehensions, and augmented assignments. The new compiler should
2914 also be backwards compatible with Python 1.5.2; the compiler will
2915 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002916 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002917
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002918What's new in 2.0 release candidate 1 (since beta 2)?
2919=====================================================
2920
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002921What is release candidate 1?
2922
2923We believe that release candidate 1 will fix all known bugs that we
2924intend to fix for the 2.0 final release. This release should be a bit
2925more stable than the previous betas. We would like to see even more
2926widespread testing before the final release, so we are producing this
2927release candidate. The final release will be exactly the same unless
2928any show-stopping (or brown bag) bugs are found by testers of the
2929release candidate.
2930
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002931All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002932to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002933
2934Core language, builtins, and interpreter
2935
2936- A bug that caused crashes when __coerce__ was used with augmented
2937 assignment, e.g. +=, was fixed.
2938
2939- Raise ZeroDivisionError when raising zero to a negative number,
2940 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2941 power operator and the result of math.pow(0.0, -2.0) will vary by
2942 platform. On Linux, it raises a ValueError.
2943
2944- A bug in Unicode string interpolation was fixed that occasionally
2945 caused errors with formats including "%%". For example, the
2946 following expression "%% %s" % u"abc" no longer raises a TypeError.
2947
2948- Compilation of deeply nested expressions raises MemoryError instead
2949 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2950
2951- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2952 rendering them useless. They are now written in binary mode again.
2953
2954Standard library
2955
2956- Keyword arguments are now accepted for most pattern and match object
2957 methods in SRE, the standard regular expression engine.
2958
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002959- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002960 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002961
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002962- Several bugs in the Unicode handling and error handling in _tkinter
2963 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002964
2965- Fix memory management errors in Merge() and Tkapp_Call() routines.
2966
2967- Several changes were made to cStringIO to make it compatible with
2968 the file-like object interface and with StringIO. If operations are
2969 performed on a closed object, an exception is raised. The truncate
2970 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002971 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002972
2973- There were many changes made to the linuxaudiodev module and its
2974 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002975 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002976
2977 Note that this module is named poorly, because it should work
2978 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002979 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002980
2981 The module now raises exceptions when errors occur instead of
2982 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2983 audio) and defines a getptr() method that calls the
2984 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2985
2986- The library_version attribute, introduced in an earlier beta, was
2987 removed because it can not be supported with early versions of the C
2988 readline library, which provides no way to determine the version at
2989 compile-time.
2990
2991- The binascii module is now enabled on Win64.
2992
Tim Peters46446d62000-10-09 21:19:31 +00002993- tokenize.py no longer suffers "recursion depth" errors when parsing
2994 programs with very long string literals.
2995
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002996Internals
2997
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002998- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002999 which is called when the interpreter starts up to determine where
3000 the standard library is installed. These vulnerabilities affect all
3001 previous versions of Python and can be exploited by setting very
3002 long values for PYTHONHOME or argv[0]. The risk is greatest for a
3003 setuid Python script, although use of the wrapper in
3004 Misc/setuid-prog.c will eliminate the vulnerability.
3005
3006- Fixed garbage collection bugs in instance creation that were
3007 triggered when errors occurred during initialization. The solution,
3008 applied in cPickle and in PyInstance_New(), is to call
3009 PyObject_GC_Init() after the initialization of the object's
3010 container attributes is complete.
3011
3012- pyexpat adds definitions of PyModule_AddStringConstant and
3013 PyModule_AddObject if the Python version is less than 2.0, which
3014 provides compatibility with PyXML on Python 1.5.2.
3015
3016- If the platform has a bogus definition for LONG_BIT (the number of
3017 bits in a long), an error will be reported at compile time.
3018
3019- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
3020 collection crashes and possibly other, unreported crashes.
3021
3022- Fixed a memory leak in _PyUnicode_Fini().
3023
3024Build issues
3025
3026- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003027 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00003028 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003029
3030- The mmap.PAGESIZE constant is now initialized using sysconf when
3031 possible, which eliminates a dependency on -lucb for Reliant UNIX.
3032
3033- The md5 file should now compile on all platforms.
3034
3035- The select module now compiles on platforms that do not define
3036 POLLRDNORM and related constants.
3037
3038- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00003039 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003040
Jeremy Hylton10921202000-10-09 18:34:12 +00003041- BeOS: A number of changes were made to the build and installation
3042 process. ar-fake now operates on a directory of object files.
3043 dl_export.h is gone, and its macros now appear on the mwcc command
3044 line during build on PPC BeOS.
3045
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003046- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00003047 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003048
3049- Cygwin: Support for shared libraries, Tkinter, and sockets.
3050
3051- SunOS 4.1.4_JL: Fix test for directory existence in configure.
3052
3053Tools and other miscellany
3054
3055- Removed debugging prints from main used with freeze.
3056
Tim Peters46446d62000-10-09 21:19:31 +00003057- IDLE auto-indent no longer crashes when it encounters Unicode
3058 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003059
3060What's new in 2.0 beta 2 (since beta 1)?
3061========================================
3062
3063Core language, builtins, and interpreter
3064
Tim Peters482c0212000-09-26 06:33:09 +00003065- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003066 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003067
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003068- Add -h and -V command line options to print the usage message and
3069 Python version number and exit immediately.
3070
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003071- eval() and exec accept Unicode objects as code parameters.
3072
3073- getattr() and setattr() now also accept Unicode objects for the
3074 attribute name, which are converted to strings using the default
3075 encoding before lookup.
3076
3077- Multiplication on string and Unicode now does proper bounds
3078 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
3079 string is too long."
3080
3081- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00003082 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003083
Jeremy Hylton1b618592000-09-26 05:32:36 +00003084
3085Standard library and extensions
3086
Guido van Rossum5b08f132001-04-16 02:05:23 +00003087- socket module: the OpenSSL code now adds support for RAND_status()
3088 and EGD (Entropy Gathering Device).
3089
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003090- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00003091 argument checking; it still takes no arguments.
3092
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003093- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003094
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003095- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003096
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003097- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003098
3099- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003100 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003101
3102- copy: Copy Unicode objects atomically.
3103
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003104- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003105
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003106- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003107
Fred Drake67233bc2000-09-26 16:40:27 +00003108- dbm: Add get() and setdefault() methods to dbm object. Add constant
3109 `library' to module that names the library used. Added doc strings
3110 and method names to error messages. Uses configure to determine
3111 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
3112 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003113
3114- distutils: Update to version 0.9.3.
3115
3116- dl: Add several dl.RTLD_ constants.
3117
3118- fpectl: Now supported on FreeBSD.
3119
3120- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
3121 found by the collector will be saved in gc.garbage. This is useful
3122 for debugging a program that creates reference cycles.
3123
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003124- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00003125 of HTTP class. Do not close socket on zero-length response. Do not
3126 crash when server sends invalid content-length header.
3127
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003128- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003129
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003130- marshal: When reading a short, sign-extend on platforms where shorts
3131 are bigger than 16 bits. When reading a long, repair the unportable
3132 sign extension that was being done for 64-bit machines. (It assumed
3133 that signed right shift sign-extends.)
3134
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003135- operator: Add contains(), invert(), __invert__() as aliases for
3136 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003137
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003138- os: Add support for popen2() and popen3() on all platforms where
3139 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003140
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003141- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00003142 clicking on a file in Explorer (or passing the file name to the
3143 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003144
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003145- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00003146 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003147
3148- pickle: Now raises ValueError when an invalid pickle that contains
3149 a non-string repr where a string repr was expected. This behavior
3150 matches cPickle.
3151
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003152- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003153
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003154- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003155
3156- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003157 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003158 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003159
3160- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003161 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003162
3163- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00003164 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00003165 few cycles during startup since the first call to
3166 setdefaultencoding() will initialize the codec registry and the
3167 encodings package.
3168
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003169- socket: Support for size hint in readlines() method of object returned
3170 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003171
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003172- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00003173 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00003174 is followed by whitespace.
3175
Tim Petersa3a3a032000-11-30 05:22:44 +00003176- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003177
3178- struct: Check ranges for bytes and shorts.
3179
3180- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003181 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003182
3183- Tkinter: Image objects are now guaranteed to have unique ids. Set
3184 event.delta to zero if Tk version doesn't support mousewheel.
3185 Removed some debugging prints.
3186
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003187- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003188
Fred Drake67233bc2000-09-26 16:40:27 +00003189- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003190 which works around a bug in Norton AntiVirus 2000 that leads directly
3191 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003192
3193- xml: New version detection code allows PyXML to override standard
3194 XML package if PyXML version is greater than 0.6.1.
3195
Fred Drake64bb3802000-09-26 16:21:35 +00003196- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
3197 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
3198 tree only for nodes which are sufficiently interesting to a specific
3199 application. Does not provide the HTML-specific extensions. Still
3200 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003201
Fred Drake64bb3802000-09-26 16:21:35 +00003202- xml.sax: SAX 2 support for Python, including all the handler
3203 interfaces needed to process XML 1.0 compliant XML. Some
3204 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003205
Fred Drake64bb3802000-09-26 16:21:35 +00003206- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
3207 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003208
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003209
Jeremy Hylton1b618592000-09-26 05:32:36 +00003210C API
3211
3212- Add three new convenience functions for module initialization --
3213 PyModule_AddObject(), PyModule_AddIntConstant(), and
3214 PyModule_AddStringConstant().
3215
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003216- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00003217 removed and add #error to Python.h if NULL isn't defined after
3218 #include of stdio.h.
3219
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003220- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00003221 backwards compatibility (at the source level) with old extensions.
3222
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003223- A wrapper API was added for signal() and sigaction(). Instead of
3224 either function, always use PyOS_getsig() to get a signal handler
3225 and PyOS_setsig() to set one. A new convenience typedef
3226 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003227
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003228- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00003229 internal data buffer and size of a string object -- or the default
3230 encoded version of a Unicode object.
3231
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003232- PyString_Size() and PyString_AsString() accept Unicode objects.
3233
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003234- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00003235 exists). INT_MAX and LONG_MAX will always be defined, even if
3236 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003237
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003238- PyFloat_FromString takes a second argument, pend, that was
3239 effectively useless. It is now officially useless but preserved for
3240 backwards compatibility. If the pend argument is not NULL, *pend is
3241 set to NULL.
3242
3243- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
3244 for the attribute name. See note on getattr() above.
3245
3246- A few bug fixes to argument processing for Unicode.
3247 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
3248 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
3249 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00003250 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003251
3252- Py_BuildValue accepts B format (for bgen-generated code).
3253
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003254
Jeremy Hylton1b618592000-09-26 05:32:36 +00003255Internals
3256
3257- On Unix, fix code for finding Python installation directory so that
3258 it works when argv[0] is a relative path.
3259
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00003260- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003261 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00003262 rather than by generating a copy of the object.
3263
Tim Peters482c0212000-09-26 06:33:09 +00003264- Several of the internal Unicode tables are much smaller now, and
3265 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003266
Jeremy Hylton97693b02000-09-26 17:42:51 +00003267- In the garbage collector: Fixed bug in collection of tuples. Fixed
3268 bug that caused some instances to be removed from the container set
3269 while they were still live. Fixed parsing in gc.set_debug() for
3270 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003271
3272- Fixed refcount problem in instance deallocation that only occurred
3273 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
3274
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003275- On Windows, getpythonregpath is now protected against null data in
3276 registry key.
3277
3278- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00003279 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003280
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003281
Jeremy Hylton1b618592000-09-26 05:32:36 +00003282Build and platform-specific issues
3283
3284- Better support of GNU Pth via --with-pth configure option.
3285
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003286- Python/C API now properly exposed to dynamically-loaded extension
3287 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003288
3289- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
3290 Don't define MS_SYNC to be zero when it is undefined. Added missing
3291 prototypes in posixmodule.c.
3292
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003293- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003294 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003295
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003296- Fix largefile support on older NetBSD systems and OpenBSD by adding
3297 define for TELL64.
3298
3299
3300Tools and other miscellany
3301
3302- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
3303
3304- freeze: The modulefinder now works with 2.0 opcodes.
3305
Tim Petersa3a3a032000-11-30 05:22:44 +00003306- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003307 Move hackery of sys.argv until after the Tk instance has been
3308 created, which allows the application-specific Tkinter
3309 initialization to be executed if present; also pass an explicit
3310 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00003311
Jeremy Hylton1b618592000-09-26 05:32:36 +00003312
3313What's new in 2.0 beta 1?
3314=========================
3315
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003316Source Incompatibilities
3317------------------------
3318
3319None. Note that 1.6 introduced several incompatibilities with 1.5.2,
3320such as single-argument append(), connect() and bind(), and changes to
3321str(long) and repr(float).
3322
3323
3324Binary Incompatibilities
3325------------------------
3326
3327- Third party extensions built for Python 1.5.x or 1.6 cannot be used
3328with Python 2.0; these extensions will have to be rebuilt for Python
33292.0.
3330
3331- On Windows, attempting to import a third party extension built for
3332Python 1.5.x or 1.6 results in an immediate crash; there's not much we
3333can do about this. Check your PYTHONPATH environment variable!
3334
3335- Python bytecode files (*.pyc and *.pyo) are not compatible between
3336releases.
3337
3338
3339Overview of Changes Since 1.6
3340-----------------------------
3341
3342There are many new modules (including brand new XML support through
3343the xml package, and i18n support through the gettext module); a list
3344of all new modules is included below. Lots of bugs have been fixed.
3345
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003346The process for making major new changes to the language has changed
3347since Python 1.6. Enhancements must now be documented by a Python
3348Enhancement Proposal (PEP) before they can be accepted.
3349
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003350There are several important syntax enhancements, described in more
3351detail below:
3352
3353 - Augmented assignment, e.g. x += 1
3354
3355 - List comprehensions, e.g. [x**2 for x in range(10)]
3356
3357 - Extended import statement, e.g. import Module as Name
3358
3359 - Extended print statement, e.g. print >> file, "Hello"
3360
3361Other important changes:
3362
3363 - Optional collection of cyclical garbage
3364
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003365Python Enhancement Proposal (PEP)
3366---------------------------------
3367
3368PEP stands for Python Enhancement Proposal. A PEP is a design
3369document providing information to the Python community, or describing
3370a new feature for Python. The PEP should provide a concise technical
3371specification of the feature and a rationale for the feature.
3372
3373We intend PEPs to be the primary mechanisms for proposing new
3374features, for collecting community input on an issue, and for
3375documenting the design decisions that have gone into Python. The PEP
3376author is responsible for building consensus within the community and
3377documenting dissenting opinions.
3378
3379The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003380
3381Augmented Assignment
3382--------------------
3383
3384This must have been the most-requested feature of the past years!
3385Eleven new assignment operators were added:
3386
Guido van Rossume905e952000-09-05 12:42:46 +00003387 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003388
3389For example,
3390
3391 A += B
3392
3393is similar to
3394
3395 A = A + B
3396
3397except that A is evaluated only once (relevant when A is something
3398like dict[index].attr).
3399
3400However, if A is a mutable object, A may be modified in place. Thus,
3401if A is a number or a string, A += B has the same effect as A = A+B
3402(except A is only evaluated once); but if a is a list, A += B has the
3403same effect as A.extend(B)!
3404
3405Classes and built-in object types can override the new operators in
3406order to implement the in-place behavior; the not-in-place behavior is
3407used automatically as a fallback when an object doesn't implement the
3408in-place behavior. For classes, the method name is derived from the
3409method name for the corresponding not-in-place operator by inserting
3410an 'i' in front of the name, e.g. __iadd__ implements in-place
3411__add__.
3412
3413Augmented assignment was implemented by Thomas Wouters.
3414
3415
3416List Comprehensions
3417-------------------
3418
3419This is a flexible new notation for lists whose elements are computed
3420from another list (or lists). The simplest form is:
3421
3422 [<expression> for <variable> in <sequence>]
3423
Guido van Rossum56db0952000-09-06 23:34:25 +00003424For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003425This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003426
3427You can also add a condition:
3428
3429 [<expression> for <variable> in <sequence> if <condition>]
3430
3431For example, [w for w in words if w == w.lower()] would yield the list
3432of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003433than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003434
3435You can also have nested for loops and more than one 'if' clause. For
3436example, here's a function that flattens a sequence of sequences::
3437
3438 def flatten(seq):
3439 return [x for subseq in seq for x in subseq]
3440
3441 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3442
3443This prints
3444
3445 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3446
3447List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003448Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003449
3450
3451Extended Import Statement
3452-------------------------
3453
3454Many people have asked for a way to import a module under a different
3455name. This can be accomplished like this:
3456
3457 import foo
3458 bar = foo
3459 del foo
3460
3461but this common idiom gets old quickly. A simple extension of the
3462import statement now allows this to be written as follows:
3463
3464 import foo as bar
3465
3466There's also a variant for 'from ... import':
3467
3468 from foo import bar as spam
3469
3470This also works with packages; e.g. you can write this:
3471
3472 import test.regrtest as regrtest
3473
3474Note that 'as' is not a new keyword -- it is recognized only in this
3475context (this is only possible because the syntax for the import
3476statement doesn't involve expressions).
3477
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003478Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003479
3480
3481Extended Print Statement
3482------------------------
3483
3484Easily the most controversial new feature, this extension to the print
3485statement adds an option to make the output go to a different file
3486than the default sys.stdout.
3487
3488For example, to write an error message to sys.stderr, you can now
3489write:
3490
3491 print >> sys.stderr, "Error: bad dog!"
3492
3493As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003494evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003495
3496 print >> None, "Hello world"
3497
3498is equivalent to
3499
3500 print "Hello world"
3501
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003502Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003503
3504
3505Optional Collection of Cyclical Garbage
3506---------------------------------------
3507
3508Python is now equipped with a garbage collector that can hunt down
3509cyclical references between Python objects. It's no replacement for
3510reference counting; in fact, it depends on the reference counts being
3511correct, and decides that a set of objects belong to a cycle if all
3512their reference counts can be accounted for from their references to
3513each other. This devious scheme was first proposed by Eric Tiedemann,
3514and brought to implementation by Neil Schemenauer.
3515
3516There's a module "gc" that lets you control some parameters of the
3517garbage collection. There's also an option to the configure script
3518that lets you enable or disable the garbage collection. In 2.0b1,
3519it's on by default, so that we (hopefully) can collect decent user
3520experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003521performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003522off by default in the final 2.0 release.
3523
3524
3525Smaller Changes
3526---------------
3527
3528A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3529map(None, seq1, seq2, ...) when the sequences have the same length;
3530i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3531the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003532zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003533
3534sys.version_info is a tuple (major, minor, micro, level, serial).
3535
3536Dictionaries have an odd new method, setdefault(key, default).
3537dict.setdefault(key, default) returns dict[key] if it exists; if not,
3538it sets dict[key] to default and returns that value. Thus:
3539
3540 dict.setdefault(key, []).append(item)
3541
3542does the same work as this common idiom:
3543
3544 if not dict.has_key(key):
3545 dict[key] = []
3546 dict[key].append(item)
3547
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003548There are two new variants of SyntaxError that are raised for
3549indentation-related errors: IndentationError and TabError.
3550
3551Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3552escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003553
3554The limits on the size of expressions and file in Python source code
3555have been raised from 2**16 to 2**32. Previous versions of Python
3556were limited because the maximum argument size the Python VM accepted
3557was 2**16. This limited the size of object constructor expressions,
3558e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3559limit was raised thanks to a patch by Charles Waldman that effectively
3560fixes the problem. It is now much more likely that you will be
3561limited by available memory than by an arbitrary limit in Python.
3562
3563The interpreter's maximum recursion depth can be modified by Python
3564programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3565limit is the maximum number of recursive calls that can be made by
3566Python code. The limit exists to prevent infinite recursion from
3567overflowing the C stack and causing a core dump. The default value is
35681000. The maximum safe value for a particular platform can be found
3569by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003570
3571New Modules and Packages
3572------------------------
3573
3574atexit - for registering functions to be called when Python exits.
3575
3576imputil - Greg Stein's alternative API for writing custom import
3577hooks.
3578
3579pyexpat - an interface to the Expat XML parser, contributed by Paul
3580Prescod.
3581
3582xml - a new package with XML support code organized (so far) in three
3583subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3584would fill a volume. There's a special feature whereby a
3585user-installed package named _xmlplus overrides the standard
3586xmlpackage; this is intended to give the XML SIG a hook to distribute
3587backwards-compatible updates to the standard xml package.
3588
3589webbrowser - a platform-independent API to launch a web browser.
3590
3591
Guido van Rossume905e952000-09-05 12:42:46 +00003592Changed Modules
3593---------------
3594
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003595array -- new methods for array objects: count, extend, index, pop, and
3596remove
3597
3598binascii -- new functions b2a_hex and a2b_hex that convert between
3599binary data and its hex representation
3600
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003601calendar -- Many new functions that support features including control
3602over which day of the week is the first day, returning strings instead
3603of printing them. Also new symbolic constants for days of week,
3604e.g. MONDAY, ..., SUNDAY.
3605
3606cgi -- FieldStorage objects have a getvalue method that works like a
3607dictionary's get method and returns the value attribute of the object.
3608
3609ConfigParser -- The parser object has new methods has_option,
3610remove_section, remove_option, set, and write. They allow the module
3611to be used for writing config files as well as reading them.
3612
3613ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003614optionally support the RFC 959 REST command.
3615
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003616gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003617
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003618httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3619the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003620
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003621locale -- implement getdefaultlocale for Win32 and Macintosh
3622
3623marshal -- no longer dumps core when marshaling deeply nested or
3624recursive data structures
3625
3626os -- new functions isatty, seteuid, setegid, setreuid, setregid
3627
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003628os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3629support under Unix.
3630
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003631os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003632
3633os.path -- fix semantics of os.path.commonprefix
3634
3635smtplib -- support for sending very long messages
3636
3637socket -- new function getfqdn()
3638
3639readline -- new functions to read, write and truncate history files.
3640The readline section of the library reference manual contains an
3641example.
3642
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003643select -- add interface to poll system call
3644
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003645shutil -- new copyfileobj function
3646
3647SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3648HTTP server.
3649
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003650Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003651
3652urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003653e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003654
3655whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003656
3657
3658Obsolete Modules
3659----------------
3660
3661None. However note that 1.6 made a whole slew of modules obsolete:
3662stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3663poly, zmod, strop, util, whatsound.
3664
3665
3666Changed, New, Obsolete Tools
3667----------------------------
3668
Tim Peters8b092332000-09-05 20:15:25 +00003669None.
Guido van Rossume905e952000-09-05 12:42:46 +00003670
3671
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003672C-level Changes
3673---------------
3674
3675Several cleanup jobs were carried out throughout the source code.
3676
3677All C code was converted to ANSI C; we got rid of all uses of the
3678Py_PROTO() macro, which makes the header files a lot more readable.
3679
3680Most of the portability hacks were moved to a new header file,
3681pyport.h; several other new header files were added and some old
3682header files were removed, in an attempt to create a more rational set
3683of header files. (Few of these ever need to be included explicitly;
3684they are all included by Python.h.)
3685
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003686Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003687and Win64, especially for the new Intel Itanium processor. Mick also
3688added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003689
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003690The C APIs to return an object's size have been update to consistently
3691use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3692previous versions, the abstract interfaces used PyXXX_Length and the
3693concrete interfaces used PyXXX_Size. The old names,
3694e.g. PyObject_Length, are still available for backwards compatibility
3695at the API level, but are deprecated.
3696
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003697The PyOS_CheckStack function has been implemented on Windows by
3698Fredrik Lundh. It prevents Python from failing with a stack overflow
3699on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003700
3701The GC changes resulted in creation of two new slots on object,
3702tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003703the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003704
3705The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003706C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003707
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003708PyErr_Format has been updated to automatically calculate the size of
3709the buffer needed to hold the formatted result string. This change
3710prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003711
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003712New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003713
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003714PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3715that are the same as their non-Ex counterparts except they take an
3716extra flag argument that tells them to close the file when done.
3717
3718XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003719
Tim Peters8b092332000-09-05 20:15:25 +00003720
3721Windows Changes
3722---------------
3723
3724New popen2/popen3/peopen4 in os module (see Changed Modules above).
3725
3726os.popen is much more usable on Windows 95 and 98. See Microsoft
3727Knowledge Base article Q150956. The Win9x workaround described there
3728is implemented by the new w9xpopen.exe helper in the root of your
3729Python installation. Note that Python uses this internally; it is not
3730a standalone program.
3731
3732Administrator privileges are no longer required to install Python
3733on Windows NT or Windows 2000. If you have administrator privileges,
3734Python's registry info will be written under HKEY_LOCAL_MACHINE.
3735Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003736under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003737uses of Python, but will prevent some advanced uses from working
3738(for example, running a Python script as an NT service, or possibly
3739from CGI).
3740
3741[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3742installer; instead, it installs the needed Tcl/Tk files directly in the
3743Python directory. If you already have a Tcl/Tk installation, this
3744wastes some disk space (about 4 Megs) but avoids problems with
3745conflicting Tcl/Tk installations, and makes it much easier for Python
3746to ensure that Tcl/Tk can find all its files.
3747
3748[This was new in 1.6] The Windows installer now installs by default in
3749\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3750
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003751
3752Updates to the changes between 1.5.2 and 1.6
3753--------------------------------------------
3754
3755The 1.6 NEWS file can't be changed after the release is done, so here
3756is some late-breaking news:
3757
3758New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3759and changes to getlocale() and setlocale().
3760
3761The new module is now enabled per default.
3762
3763It is not true that the encodings codecs cannot be used for normal
3764strings: the string.encode() (which is also present on 8-bit strings
3765!) allows using them for 8-bit strings too, e.g. to convert files from
3766cp1252 (Windows) to latin-1 or vice-versa.
3767
3768Japanese codecs are available from Tamito KAJIYAMA:
3769http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3770
3771
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003772======================================================================