blob: 2c9d83f40dbb3d8066e08526ff30a25f4f2bed15 [file] [log] [blame]
Tim Petersaf8446f2001-12-21 21:36:50 +00001What's New in Python 2.3 alpha 1?
2XXX Release date: DD-MMM-2002 XXX
3=================================
4
5Type/class unification and new-style classes
6
Guido van Rossume3438782002-08-12 03:42:03 +00007- Assignment to __class__ is disallowed if either the old and the new
8 class is a statically allocated type object (such as defined by an
9 extenson module). This prevents anomalies like 2.__class__ = bool.
10
11- New-style object creation and deallocation have been sped up
12 significantly; they are now faster than classic instance creation
13 and deallocation.
14
15- The __slots__ variable can now mention "private" names, and the
16 right thing will happen (e.g. __slots__ = ["__foo"]).
17
18- The built-ins slice() and buffer() are now callable types. The
19 types classobj (formerly class), code, function, instance, and
20 instancemethod (formerly instance-method), which have no built-in
21 names but are accessible through the types module, are now also
22 callable. The type dict-proxy is renamed to dictproxy.
23
24- Cycles going through the __class__ link of a new-style instance are
25 now detected by the garbage collector.
26
27- Classes using __slots__ are now properly garbage collected.
28 [SF bug 519621]
29
30- Tightened the __slots__ rules: a slot name must be a valid Python
31 identifier.
32
33- The constructor for the module type now requires a name argument and
34 takes an optional docstring argument. Previously, this constructor
35 ignored its arguments. As a consequence, deriving a class from a
36 module (not from the module type) is now illegal; previously this
37 created an unnamed module, just like invoking the module type did.
38 [SF bug 563060]
39
40- A new type object, 'basestring', is added. This is a common base type
41 for 'str' and 'unicode', and can be used instead of
42 types.StringTypes, e.g. to test whether something is "a string":
43 isinstance(x, basestring) is True for Unicode and 8-bit strings. This
44 is an abstract base class and cannot be instantiated directly.
45
46- Changed new-style class instantiation so that when C's __new__
47 method returns something that's not a C instance, its __init__ is
48 not called. [SF bug #537450]
49
50- Fixed super() to work correctly with class methods. [SF bug #535444]
51
52- If you try to pickle an instance of a class that has __slots__ but
53 doesn't define or override __getstate__, a TypeError is now raised.
54 This is done by adding a bozo __getstate__ to the class that always
55 raises TypeError. (Before, this would appear to be pickled, but the
56 state of the slots would be lost.)
57
Tim Petersaf8446f2001-12-21 21:36:50 +000058Core and builtins
59
Michael W. Hudsondd32a912002-08-15 14:59:02 +000060- SET_LINENO is gone. co_lnotab is now consulted to determine when to
61 call the trace function. C code that accessed f_lineno should call
62 PyCode_Addr2Line instead (f_lineno is still there, but not kept up
63 to date).
64
Guido van Rossum9be89462002-08-14 16:11:30 +000065- There's a new warning category, FutureWarning. This is used to warn
66 about a number of situations where the value or sign of an integer
67 result will change in Python 2.4 as a result of PEP 237 (integer
68 unification). The warnings implement stage B0 mentioned in that
69 PEP. The warnings are about the following situations:
70
71 - Octal and hex literals without 'L' prefix in the inclusive range
72 [0x80000000..0xffffffff]; these are currently negative ints, but
73 in Python 2.4 they will be positive longs with the same bit
74 pattern.
75
76 - Left shifts on integer values that cause the outcome to lose
77 bits or have a different sign than the left operand. To be
78 precise: x<<n where this currently doesn't yield the same value
79 as long(x)<<n; in Python 2.4, the outcome will be long(x)<<n.
80
81 - Conversions from ints to string that show negative values as
82 unsigned ints in the inclusive range [0x80000000..0xffffffff];
83 this affects the functions hex() and oct(), and the string
84 formatting codes %u, %o, %x, and %X. In Python 2.4, these will
85 show signed values (e.g. hex(-1) currently returns "0xffffffff";
86 in Python 2.4 it will return "-0x1").
87
Tim Petersd64c1de2002-08-12 17:36:03 +000088- When multiplying very large integers, a version of the so-called
89 Karatsuba algorithm is now used. This is most effective if the
90 inputs have roughly the same size. If they both have about N digits,
91 Karatsuba multiplication has O(N**1.58) runtime (the exponent is
92 log_base_2(3)) instead of the previous O(N**2). Measured results may
93 be better or worse than that, depending on platform quirks. Note that
94 this is a simple implementation, and there's no intent here to compete
Tim Peters60004642002-08-12 22:01:34 +000095 with, e.g., GMP. It gives a very nice speedup when it applies, but
96 a package devoted to fast large-integer arithmetic should run circles
97 around it.
Tim Peters5af4e6c2002-08-12 02:31:19 +000098
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +000099- u'%c' will now raise a ValueError in case the argument is an
100 integer outside the valid range of Unicode code point ordinals.
101
Guido van Rossumdeb09362002-08-09 17:16:30 +0000102- The tempfile module has been overhauled for enhanced security. The
103 mktemp() function is now deprecated; new, safe replacements are
104 mkstemp() (for files) and mkdtemp() (for directories), and the
105 higher-level functions NamedTemporaryFile() and TemporaryFile().
106 Use of some global variables in this module is also deprecated; the
107 new functions have keyword arguments to provide the same
108 functionality. All Lib, Tools and Demo modules that used the unsafe
109 interfaces have been updated to use the safe replacements. Thanks
110 to Zack Weinberg!
111
Guido van Rossumd81a9832002-08-09 15:57:34 +0000112- When x is an object whose class implements __mul__ and __rmul__,
113 1.0*x would correctly invoke __rmul__, but 1*x would erroneously
114 invoke __mul__. This was due to the sequence-repeat code in the int
115 type. This has been fixed now.
116
Barry Warsawd79f6832002-08-06 17:01:51 +0000117- Previously, "str1 in str2" required str1 to be a string of length 1.
118 This restriction has been relaxed to allow str1 to be a string of
119 any length. Thus "'el' in 'hello world'" returns True now.
120
Guido van Rossumb57089c2002-08-06 16:20:26 +0000121- File objects are now their own iterators. For a file f, iter(f) now
122 returns f (unless f is closed), and f.next() is similar to
123 f.readline() when EOF is not reached; however, f.next() uses a
124 readahead buffer that messes up the file position, so mixing
125 f.next() and f.readline() (or other methods) doesn't work right.
126 Calling f.seek() drops the readahead buffer, but other operations
127 don't. It so happens that this gives a nice additional speed boost
128 to "for line in file:"; the xreadlines method and corresponding
Guido van Rossumbffb2ef2002-08-09 17:17:07 +0000129 module are now obsolete. Thanks to Oren Tirosh!
Guido van Rossumb57089c2002-08-06 16:20:26 +0000130
Guido van Rossumde392d32002-08-05 14:17:20 +0000131- Encoding declarations (PEP 263, phase 1) have been implemented. A
132 comment of the form "# -*- coding: <encodingname> -*-" in the first
133 or second line of a Python source file indicates the encoding.
Martin v. Löwis00f1e3f2002-08-04 17:29:52 +0000134
Tim Petersf47630f2002-08-01 02:34:51 +0000135- list.sort() has a new implementation. While cross-platform results
136 may vary, and in data-dependent ways, this is much faster on many
137 kinds of partially ordered lists than the previous implementation,
138 and reported to be just as fast on randomly ordered lists on
139 several major platforms. This sort is also stable (if A==B and A
140 precedes B in the list at the start, A precedes B after the sort too),
141 although the language definition does not guarantee stability. A
142 potential drawback is that list.sort() may require temp space of
143 len(list)*2 bytes (*4 on a 64-bit machine). It's therefore possible
144 for list.sort() to raise MemoryError now, even if a comparison function
145 does not. See <http://www.python.org/sf/587076> for full details.
146
Guido van Rossum2d5389c2002-07-23 03:44:35 +0000147- All standard iterators now ensure that, once StopIteration has been
148 raised, all future calls to next() on the same iterator will also
149 raise StopIteration. There used to be various counterexamples to
150 this behavior, which could caused confusion or subtle program
151 breakage, without any benefits. (Note that this is still an
152 iterator's responsibility; the iterator framework does not enforce
153 this.)
154
Mark Hammondc0e35152002-07-16 01:32:30 +0000155- Ctrl+C handling on Windows has been made more consistent with
156 other platforms. KeyboardInterrupt can now reliably be caught,
Tim Petersf47630f2002-08-01 02:34:51 +0000157 and Ctrl+C at an interative prompt no longer terminates the
Mark Hammondc0e35152002-07-16 01:32:30 +0000158 process under NT/2k/XP (it never did under Win9x). Ctrl+C will
Tim Peters5af4e6c2002-08-12 02:31:19 +0000159 interrupt time.sleep() in the main thread, and any child processes
160 created via the popen family (on win2k; we can't make win9x work
Mark Hammond8f3afc72002-08-10 06:26:31 +0000161 reliably) are also interrupted (as generally happens on for Linux/Unix.)
162 [SF bugs 231273, 439992 and 581232]
Mark Hammondc0e35152002-07-16 01:32:30 +0000163
Raymond Hettinger5a04aec2002-06-25 00:25:30 +0000164- Slices and repetitions of buffer objects now consistently return
165 a string. Formerly, strings would be returned most of the time,
166 but a buffer object would be returned when the repetition count
167 was one or when the slice range was all inclusive.
168
Walter Dörwald3430d702002-06-17 10:43:59 +0000169- Unicode objects in sys.path are no longer ignored but treated
170 as directory names.
171
Neal Norwitz1f68fc72002-06-14 00:50:42 +0000172- Fixed string.startswith and string.endswith builtin methods
173 so they accept negative indices. [SF bug 493951]
174
Guido van Rossumc5fe5eb2002-06-12 03:45:21 +0000175- Fixed a bug with a continue inside a try block and a yield in the
176 finally clause. [SF bug 567538]
177
Michael W. Hudson5efaf7e2002-06-11 10:55:12 +0000178- Most builtin sequences now support "extended slices", i.e. slices
Guido van Rossum2e82e712002-06-13 11:41:07 +0000179 with a third "stride" parameter. For example, "hello world"[::-1]
180 gives "dlrow olleh".
Michael W. Hudson5efaf7e2002-06-11 10:55:12 +0000181
Neal Norwitzd68f5172002-05-29 15:54:55 +0000182- A new warning PendingDeprecationWarning was added to provide
183 direction on features which are in the process of being deprecated.
184 The warning will not be printed by default. To see the pending
185 deprecations, use -Walways::PendingDeprecationWarning::
186 as a command line option or warnings.filterwarnings() in code.
187
Fred Draked0ba6362002-05-02 21:28:26 +0000188- Deprecated features of xrange objects have been removed as
189 promised. The start, stop, and step attributes and the tolist()
190 method no longer exist. xrange repetition and slicing have been
191 removed.
192
Guido van Rossum7dab2422002-04-26 19:40:56 +0000193- New builtin function enumerate(x), from PEP 279. Example:
194 enumerate("abc") is an iterator returning (0,"a"), (1,"b"), (2,"c").
195 The argument can be an arbitrary iterable object.
196
Neil Schemenauer89e3ee02002-04-26 01:58:53 +0000197- The assert statement no longer tests __debug__ at runtime. This means
198 that assert statements cannot be disabled by assigning a false value
199 to __debug__.
200
Walter Dörwald068325e2002-04-15 13:36:47 +0000201- A method zfill() was added to str and unicode, that fills a numeric
202 string to the left with zeros. For example,
203 "+123".zfill(6) -> "+00123".
204
Guido van Rossum862fe3c2002-04-15 12:36:47 +0000205- Complex numbers supported divmod() and the // and % operators, but
206 these make no sense. Since this was documented, they're being
207 deprecated now.
208
Guido van Rossum26dd8302002-04-26 20:11:29 +0000209- String and unicode methods lstrip(), rstrip() and strip() now take
210 an optional argument that specifies the characters to strip. For
211 example, "Foo!!!?!?!?".rstrip("?!") -> "Foo".
Guido van Rossum49042042002-04-13 00:59:05 +0000212
Guido van Rossumc69343b2002-04-12 19:22:48 +0000213- Added a new dict method pop(key). This removes and returns the
214 value corresponding to key. [SF patch #539949]
215
Guido van Rossum47834462002-04-04 15:21:33 +0000216- A new built-in type, bool, has been added, as well as built-in
217 names for its two values, True and False. Comparisons and sundry
218 other operations that return a truth value have been changed to
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000219 return a bool instead. Read PEP 285 for an explanation of why this
Guido van Rossum47834462002-04-04 15:21:33 +0000220 is backward compatible.
221
Guido van Rossum95b62a62002-03-29 01:07:24 +0000222- Fixed two bugs reported as SF #535905: under certain conditions,
223 deallocating a deeply nested structure could cause a segfault in the
224 garbage collector, due to interaction with the "trashcan" code;
225 access to the current frame during destruction of a local variable
226 could access a pointer to freed memory.
227
Guido van Rossumfe0ca4a2002-06-18 21:20:13 +0000228- The optional object allocator ("pymalloc") has been enabled by
229 default. The recommended practice for memory allocation and
230 deallocation has been streamlined. A header file is included,
231 Misc/pymemcompat.h, which can be bundled with 3rd party extensions
232 and lets them use the same API with Python versions from 1.5.2
233 onwards.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000234
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +0000235- PyErr_Display will provide file and line information for all exceptions
236 that have an attribute print_file_and_line, not just SyntaxErrors.
237
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000238- The UTF-8 codec will now encode and decode Unicode surrogates
239 correctly and without raising exceptions for unpaired ones.
240
Guido van Rossumadd88062002-08-15 14:01:14 +0000241- Universal newlines (PEP 278) is implemented. Briefly, using 'U'
242 instead of 'r' when opening a text file for reading changes the line
243 ending convention so that any of '\r', '\r\n', and '\n' is
244 recognized (even mixed in one file); all three are converted to
245 '\n', the standard Python line end character.
246
Neal Norwitz649b7592002-01-01 19:07:13 +0000247- file.xreadlines() now raises a ValueError if the file is closed:
248 Previously, an xreadlines object was returned which would raise
249 a ValueError when the xreadlines.next() method was called.
250
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000251- sys.exit() inadvertently allowed more than one argument.
Neal Norwitz0c766a02002-03-27 13:03:09 +0000252 An exception will now be raised if more than one argument is used.
253
Tim Petersaf8446f2001-12-21 21:36:50 +0000254Extension modules
255
Guido van Rossumb57089c2002-08-06 16:20:26 +0000256- The xreadlines module is slated for obsolescence.
257
Guido van Rossum79f0a102002-07-23 03:32:08 +0000258- The strptime function in the time module is now always available (a
259 Python implementation is used when the C library doesn't define it).
260
Guido van Rossum9562bcf2002-06-14 21:31:18 +0000261- The 'new' module is no longer an extension, but a Python module that
262 only exists for backwards compatibility. Its contents are no longer
263 functions but callable type objects.
264
Tim Peters81b92512002-04-29 01:37:32 +0000265- The bsddb.*open functions can now take 'None' as a filename.
Anthony Baxter83888952002-04-23 02:11:05 +0000266 This will create a temporary in-memory bsddb that won't be
Tim Peters81b92512002-04-29 01:37:32 +0000267 written to disk.
Anthony Baxter83888952002-04-23 02:11:05 +0000268
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000269- posix.lchown, posix.killpg, posix.mknod, and posix.getpgid have been
270 added where available.
Martin v. Löwis06a83e92002-04-14 10:19:44 +0000271
Martin v. Löwis2e64c342002-03-27 18:49:02 +0000272- The locale module now exposes the C library's gettext interface.
273
Tim Petersfbf74f22002-03-14 19:06:01 +0000274- A security hole ("double free") was found in zlib-1.1.3, a popular
275 third party compression library used by some Python modules. The
276 hole was quickly plugged in zlib-1.1.4, and the Windows build of
277 Python now ships with zlib-1.1.4.
278
Martin v. Löwis688357e2002-04-08 21:28:20 +0000279- pwd, grp, and resource return enhanced tuples now, with symbolic
280 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +0000281
Martin v. Löwis99866332002-03-01 10:27:01 +0000282- array.array is now a type object. A new format character
283 'u' indicates Py_UNICODE arrays. For those, .tounicode and
284 .fromunicode methods are available. Arrays now support __iadd__
285 and __imul__.
286
Neal Norwitze790eae2002-01-01 21:14:12 +0000287- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +0000288 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
289 is called.
290
Michael W. Hudson34f20ea2002-05-27 15:08:24 +0000291- signal.sigpending, signal.sigprocmask and signal.sigsuspend have
292 been added where available.
293
Tim Petersaf8446f2001-12-21 21:36:50 +0000294Library
295
Guido van Rossum4a57c332002-08-02 18:05:20 +0000296- New "algorithms" module: heapq, implements a heap queue. Thanks to
297 Kevin O'Connor for the code and François Pinard for an entertaining
298 write-up explaining the theory and practical uses of heaps.
299
Marc-André Lemburg58e2ff22002-07-12 14:40:04 +0000300- New encoding for the Palm OS character set: palmos.
301
Tim Peters943382c2002-07-07 03:59:34 +0000302- binascii.crc32() and the zipfile module had problems on some 64-bit
303 platforms. These have been fixed. On a platform with 8-byte C longs,
304 crc32() now returns a signed-extended 4-byte result, so that its value
305 as a Python int is equal to the value computed a 32-bit platform.
306
Martin v. Löwis7d650ca2002-06-30 15:05:00 +0000307- xml.dom.minidom.toxml and toprettyxml now take an optional encoding
308 argument.
309
Guido van Rossum9f7549b2002-06-10 21:39:42 +0000310- Some fixes in the copy module: when an object is copied through its
311 __reduce__ method, there was no check for a __setstate__ method on
312 the result [SF patch 565085]; deepcopy should treat instances of
313 custom metaclasses the same way it treats instances of type 'type'
314 [SF patch 560794].
315
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000316- Sockets now support timeout mode. After s.settimeout(T), where T is
317 a float expressing seconds, subsequent operations raise an exception
318 if they cannot be completed within T seconds. To disable timeout
Guido van Rossum79f0a102002-07-23 03:32:08 +0000319 mode, use s.settimeout(None). There's also a module function,
320 socket.setdefaulttimeout(T), which sets the default for all sockets
321 created henceforth.
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000322
323- getopt.gnu_getopt was added. This supports GNU-style option
324 processing, where options can be mixed with non-option arguments.
Martin v. Löwis446a25f2002-06-06 10:58:36 +0000325
Michael W. Hudsonb0dc1a32002-06-04 18:27:35 +0000326- Stop using strings for exceptions. String objects used for
327 exceptions are now classes deriving from Exception. The objects
328 changed were: Tkinter.TclError, bdb.BdbQuit, macpath.norm_error,
329 tabnanny.NannyNag, and xdrlib.Error.
Neal Norwitzb5b5a262002-06-04 17:14:07 +0000330
Walter Dörwald474458d2002-06-04 15:16:29 +0000331- Constants BOM_UTF8, BOM_UTF16, BOM_UTF16_LE, BOM_UTF16_BE,
332 BOM_UTF32, BOM_UTF32_LE and BOM_UTF32_BE that represent the Byte
333 Order Mark in UTF-8, UTF-16 and UTF-32 encodings for little and
334 big endian systems were added to the codecs module. The old names
335 BOM32_* and BOM64_* were off by a factor of 2.
336
Guido van Rossumf9257822002-06-18 20:43:18 +0000337- Added conversion functions math.degrees() and math.radians().
Raymond Hettinger87f59ee2002-05-13 04:17:32 +0000338
Raymond Hettinger9b1df1d2002-05-12 06:07:21 +0000339- ftplib.retrlines() now tests for callback is None rather than testing
340 for False. Was causing an error when given a callback object which
341 was callable but also returned len() as zero. The change may
342 create new breakage if the caller relied on the undocumented behavior
343 and called with callback set to [] or some other False value not
344 identical to None.
345
Tim Peters46c04e12002-05-05 20:40:00 +0000346- random.gauss() uses a piece of hidden state used by nothing else,
347 and the .seed() and .whseed() methods failed to reset it. In other
348 words, setting the seed didn't completely determine the sequence of
349 results produced by random.gauss(). It does now. Programs repeatedly
350 mixing calls to a seed method with calls to gauss() may see different
351 results now.
352
Fred Drake7f781c92002-05-01 20:33:53 +0000353- The pickle.Pickler class grew a clear_memo() method to mimic that
354 provided by cPickle.Pickler.
355
Tim Peters81b92512002-04-29 01:37:32 +0000356- difflib's SequenceMatcher class now does a dynamic analysis of
357 which elements are so frequent as to constitute noise. For
358 comparing files as sequences of lines, this generally works better
359 than the IS_LINE_JUNK function, and function ndiff's linejunk
360 argument defaults to None now as a result. A happy benefit is
361 that SequenceMatcher may run much faster now when applied
362 to large files with many duplicate lines (for example, C program
363 text with lots of repeated "}" and "return NULL;" lines).
364
Guido van Rossum256705b2002-04-23 13:29:43 +0000365- New Text.dump() method in Tkinter module.
366
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000367- New distutils commands for building packagers were added to
368 support pkgtool on Solaris and swinstall on HP-UX.
369
370- distutils now has a new abstract binary packager base class
371 command/bdist_packager, which simplifies writing packagers.
372 This will hopefully provide the missing bits to encourage
373 people to submit more packagers, e.g. for Debian, FreeBSD
374 and other systems.
375
Guido van Rossumf9257822002-06-18 20:43:18 +0000376- The UTF-16, -LE and -BE stream readers now raise a
377 NotImplementedError for all calls to .readline(). Previously, they
378 used to just produce garbage or fail with an encoding error --
379 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 +0000380 work well with these.
381
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000382- compileall now supports quiet operation.
383
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000384- The BaseHTTPServer now implements optional HTTP/1.1 persistent
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000385 connections.
386
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000387- socket module: the SSL support was broken out of the main
388 _socket module C helper and placed into a new _ssl helper
389 which now gets imported by socket.py if available and working.
390
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000391- encodings package: added aliases for all supported IANA character
392 sets
393
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000394- ftplib: to safeguard the user's privacy, anonymous login will use
395 "anonymous@" as default password, rather than the real user and host
396 name.
397
Fred Drake36736122002-01-10 13:50:31 +0000398- webbrowser: tightened up the command passed to os.system() so that
399 arbitrary shell code can't be executed because a bogus URL was
400 passed in.
401
Tim Peters11bd9942002-02-01 00:52:29 +0000402- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000403 gettext.find an optional all argument. Translations will now fallback
404 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000405
Martin v. Löwis9668b932002-01-12 11:27:42 +0000406- distutils bdist commands now offer a --skip-build option.
407
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000408- warnings.warn now accepts a Warning instance as first argument.
409
Fred Drakefed7e852002-04-04 19:36:15 +0000410- The xml.sax.expatreader.ExpatParser class will no longer create
411 circular references by using itself as the locator that gets passed
412 to the content handler implementation. [SF bug #535474]
413
Barry Warsaw47f3e2c2002-05-20 00:14:24 +0000414- The email.Parser.Parser class now properly parses strings regardless
415 of their line endings, which can be any of \r, \n, or \r\n (CR, LF,
416 or CRLF). Also, the Header class's constructor default arguments
417 has changed slightly so that an explicit maxlinelen value is always
418 honored.
419
Tim Petersaf8446f2001-12-21 21:36:50 +0000420Tools/Demos
421
Fred Drake40813b12002-08-05 15:24:19 +0000422- IDLE supports the new encoding declarations (PEP 263); it can also
423 deal with legacy 8-bit files if they use the locale's encoding. It
424 allows non-ASCII strings in the interactive shell and executes them
425 in the locale's encoding.
Martin v. Löwis98ce7b72002-08-05 15:11:26 +0000426
Marc-André Lemburg46260092002-04-04 16:17:11 +0000427- freeze.py now produces binaries which can import shared modules,
428 unlike before when this failed due to missing symbol exports in
429 the generated binary.
430
Tim Petersaf8446f2001-12-21 21:36:50 +0000431Build
432
Tim Petersf47630f2002-08-01 02:34:51 +0000433- The public Python C API will generally be declared using PyAPI_FUNC
Neal Norwitz1389f3e2002-07-22 13:21:10 +0000434 and PyAPI_DATA macros, while Python extension module init functions
435 will be declared with PyMODINIT_FUNC. DL_EXPORT/DL_IMPORT macros
436 are deprecated.
437
Tim Petersc6a3ff62002-07-08 22:11:52 +0000438- A bug was fixed that could cause COUNT_ALLOCS builds to segfault, or
439 get into infinite loops, when a new-style class got garbage-collected.
440 Unfortunately, to avoid this, the way COUNT_ALLOCS works requires
441 that new-style classes be immortal in COUNT_ALLOCS builds. Note that
442 COUNT_ALLOCS is not enabled by default, in either release or debug
443 builds, and that new-style classes are immortal only in COUNT_ALLOCS
444 builds.
445
Tim Peters943382c2002-07-07 03:59:34 +0000446- Compiling out the cyclic garbage collector is no longer an option.
447 The old symbol WITH_CYCLE_GC is now ignored, and Python.h arranges
448 that it's always defined (for the benefit of any extension modules
449 that may be conditionalizing on it). A bonus is that any extension
450 type participating in cyclic gc can choose to participate in the
451 Py_TRASHCAN mechanism now too; in the absence of cyclic gc, this used
452 to require editing the core to teach the trashcan mechanism about the
453 new type.
454
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000455- According to Annex F of the current C standard,
Tim Peters1de41bf2002-07-03 03:31:20 +0000456
457 The Standard C macro HUGE_VAL and its float and long double analogs,
458 HUGE_VALF and HUGE_VALL, expand to expressions whose values are
459 positive infinities.
460
461 Python only uses the double HUGE_VAL, and only to #define its own symbol
462 Py_HUGE_VAL. Some platforms have incorrect definitions for HUGE_VAL.
463 pyport.h used to try to worm around that, but the workarounds triggered
464 other bugs on other platforms, so we gave up. If your platform defines
465 HUGE_VAL incorrectly, you'll need to #define Py_HUGE_VAL to something
466 that works on your platform. The only instance of this I'm sure about
467 is on an unknown subset of Cray systems, described here:
468
469 http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm
470
471 Presumably 2.3a1 breaks such systems. If anyone uses such a system, help!
472
Martin v. Löwisa3fb4f72002-06-09 13:33:54 +0000473- The configure option --without-doc-strings can be used to remove the
474 doc strings from the builtin functions and modules; this reduces the
475 size of the executable.
476
Guido van Rossumadd88062002-08-15 14:01:14 +0000477- The universal newlines option (PEP 278) is on by default. On Unix
478 it can be disabled by passing --without-universal-newlines to the
479 configure script. On other platforms, remove
480 WITH_UNIVERSAL_NEWLINES from pyconfig.h.
Tim Peters639295f2002-04-21 07:30:30 +0000481
Martin v. Löwis1142de32002-03-29 16:28:31 +0000482- On Unix, a shared libpython2.3.so can be created with --enable-shared.
483
Tim Peters8deda702002-03-30 10:06:07 +0000484- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
485 preprocessor symbols were eliminated. The internal decisions they
486 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000487
Fred Drake7d28b732002-05-02 21:17:00 +0000488- The tools used to build the documentation now work under Cygwin as
489 well as Unix.
490
Skip Montanaro57454e52002-06-14 20:30:31 +0000491- The bsddb and dbm module builds have been changed to try and avoid version
492 skew problems and disable linkage with Berkeley DB 1.85 unless the
493 installer knows what s/he's doing. See the section on building these
494 modules in the README file for details.
495
Tim Petersaf8446f2001-12-21 21:36:50 +0000496C API
497
Guido van Rossumfdb86482002-08-14 21:20:32 +0000498- The Py_InitModule*() functions now accept NULL for the 'methods'
499 argument. Modules without global functions are becoming more common
500 now that factories can be types rather than functions.
501
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +0000502- New C API PyUnicode_FromOrdinal() which exposes unichr() at C
503 level.
504
Thomas Heller085358a2002-07-29 14:27:41 +0000505- New functions PyErr_SetExcFromWindowsErr() and
506 PyErr_SetExcFromWindowsErrWithFilename(). Similar to
507 PyErr_SetFromWindowsErrWithFilename() and
508 PyErr_SetFromWindowsErr(), but they allow to specify
509 the exception type to raise. Available on Windows.
510
Tim Peters7c321a82002-07-09 02:57:01 +0000511- Py_FatalError() is now declared as taking a const char* argument. It
512 was previously declared without const. This should not affect working
513 code.
514
Martin v. Löwis01f94bd2002-05-08 08:44:21 +0000515- Added new macro PySequence_ITEM(o, i) that directly calls
516 sq_item without rechecking that o is a sequence and without
517 adjusting for negative indices.
518
Fred Draked0ba6362002-05-02 21:28:26 +0000519- PyRange_New() now raises ValueError if the fourth argument is not 1.
520 This is part of the removal of deprecated features of the xrange
521 object.
522
Guido van Rossum517c7d42002-04-26 02:49:14 +0000523- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
524 coercion if both arguments have the same type but this type has the
525 CHECKTYPES flag set. This is to better support proxies.
526
Neil Schemenauer9344b142002-04-12 23:00:08 +0000527- The type of tp_free has been changed from "void (*)(PyObject *)" to
528 "void (*)(void *)".
529
530- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
531
Guido van Rossum0986d822002-04-08 01:38:42 +0000532- A type can now inherit its metatype from its base type. Previously,
533 when PyType_Ready() was called, if ob_type was found to be NULL, it
534 was always set to &PyType_Type; now it is set to base->ob_type,
535 where base is tp_base, defaulting to &PyObject_Type.
536
537- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
538
Neil Schemenauerc9abc1d2002-05-08 14:14:41 +0000539- The PyCore_* family of APIs have been removed.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000540
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000541- The "u#" parser marker will now pass through Unicode objects as-is
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000542 without going through the buffer API.
543
Martin v. Löwis7198a522002-01-01 19:59:11 +0000544- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
545
Tim Peters10a3bb52001-12-25 19:07:38 +0000546- An old #define of ANY as void has been removed from pyport.h. This
547 hasn't been used since Python's pre-ANSI days, and the #define has
548 been marked as obsolete since then. SF bug 495548 says it created
549 conflicts with other packages, so keeping it around wasn't harmless.
550
Tim Petersaf8446f2001-12-21 21:36:50 +0000551- Because Python's magic number scheme broke on January 1st, we decided
552 to stop Python development. Thanks for all the fish!
553
Tim Petersfb05db22002-03-11 00:24:00 +0000554- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000555 scheme to a new one. See Python/import.c for details.
556
Tim Petersaf8446f2001-12-21 21:36:50 +0000557New platforms
558
Martin v. Löwisf90ae202002-06-11 06:22:31 +0000559- AtheOS is now supported.
560
Andrew MacIntyre161ad0e2002-08-04 07:25:58 +0000561- the EMX runtime environment on OS/2 is now supported.
562
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000563- GNU/Hurd is now supported.
564
Tim Petersaf8446f2001-12-21 21:36:50 +0000565Tests
566
567Windows
568
Tim Peters08e72952002-04-16 20:48:01 +0000569- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
570 of that has been fixed in the installer (disabled Wise's "delete in-
571 use files" uninstall option).
572
Guido van Rossum181e41a2002-04-06 00:23:25 +0000573- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
574
Tim Peters33187922002-04-04 20:02:04 +0000575- The installer now installs Start menu shortcuts under (the local
576 equivalent of) "All Users" when doing an Admin install.
577
Tim Petersfb05db22002-03-11 00:24:00 +0000578- file.truncate([newsize]) now works on Windows for all newsize values.
579 It used to fail if newsize didn't fit in 32 bits, reflecting a
580 limitation of MS _chsize (which is no longer used).
581
Tim Petersab034fa2002-02-01 11:27:43 +0000582- os.waitpid() is now implemented for Windows, and can be used to block
583 until a specified process exits. This is similar to, but not exactly
584 the same as, os.waitpid() on POSIX systems. If you're waiting for
585 a specific process whose pid was obtained from one of the spawn()
586 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000587 See the docs for details. The docs were changed to clarify that
588 spawn functions return, and waitpid requires, a process handle on
589 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000590
Tim Peters11bd9942002-02-01 00:52:29 +0000591- New tempfile.TemporaryFile implementation for Windows: this doesn't
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000592 need a TemporaryFileWrapper wrapper anymore, and should be immune
Tim Peters11bd9942002-02-01 00:52:29 +0000593 to a nasty problem: before 2.3, if you got a temp file on Windows, it
594 got wrapped in an object whose close() method first closed the
595 underlying file, then deleted the file. This usually worked fine.
596 However, the spawn family of functions on Windows create (at a low C
597 level) the same set of open files in the spawned process Q as were
598 open in the spawning process P. If a temp file f was among them, then
599 doing f.close() in P first closed P's C-level file handle on f, but Q's
600 C-level file handle on f remained open, so the attempt in P to delete f
601 blew up with a "Permission denied" error (Windows doesn't allow
602 deleting open files). This was surprising, subtle, and difficult to
603 work around.
604
605- The os module now exports all the symbolic constants usable with the
606 low-level os.open() on Windows: the new constants in 2.3 are
607 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
608 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
609 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
610 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
611 (so specify both if you want both; note that neither is useful unless
612 specified with O_CREAT too).
613
Tim Petersaf8446f2001-12-21 21:36:50 +0000614Mac
615
616
Tim Peters909c0912001-12-14 23:16:18 +0000617What's New in Python 2.2 final?
618Release date: 21-Dec-2001
619===============================
620
621Type/class unification and new-style classes
622
Barry Warsaw52acb492001-12-21 20:04:22 +0000623- pickle.py, cPickle: allow pickling instances of new-style classes
624 with a custom metaclass.
625
Tim Peters909c0912001-12-14 23:16:18 +0000626Core and builtins
627
Barry Warsaw52acb492001-12-21 20:04:22 +0000628- weakref proxy object: when comparing, unwrap both arguments if both
629 are proxies.
630
Tim Peters909c0912001-12-14 23:16:18 +0000631Extension modules
632
Barry Warsaw52acb492001-12-21 20:04:22 +0000633- binascii.b2a_base64(): fix a potential buffer overrun when encoding
634 very short strings.
635
636- cPickle: the obscure "fast" mode was suspected of causing stack
637 overflows on the Mac. Hopefully fixed this by setting the recursion
638 limit much smaller. If the limit is too low (it only affects
639 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
640 when compiling cPickle.c (or in pyconfig.h).
641
Tim Peters909c0912001-12-14 23:16:18 +0000642Library
643
Barry Warsaw52acb492001-12-21 20:04:22 +0000644- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
645 close or delete time).
646
647- rfc822.py: fixed a bug where the address '<>' was converted to None
648 instead of an empty string (also fixes the email.Utils module).
649
650- xmlrpclib.py: version 1.0.0; uses precision for doubles.
651
652- test suite: the pickle and cPickle tests were not executing any code
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000653 when run from the standard regression test.
Barry Warsaw52acb492001-12-21 20:04:22 +0000654
Tim Peters909c0912001-12-14 23:16:18 +0000655Tools/Demos
656
657Build
658
659C API
660
661New platforms
662
663Tests
664
665Windows
666
Barry Warsaw52acb492001-12-21 20:04:22 +0000667- distutils package: fixed broken Windows installers (bdist_wininst).
668
669- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
670 instances are deleted at process exit time.
671
672- socket.py: prevent mysterious warnings when socket instances are
673 deleted at process exit time.
674
675- posixmodule.c: fix a Windows crash with stat() of a filename ending
676 in backslash.
677
Tim Peters909c0912001-12-14 23:16:18 +0000678Mac
679
Barry Warsaw52acb492001-12-21 20:04:22 +0000680- The Carbon toolbox modules have been upgraded to Universal Headers
681 3.4, and experimental CoreGraphics and CarbonEvents modules have
682 been added. All only for framework-enabled MacOSX.
683
Tim Peters909c0912001-12-14 23:16:18 +0000684
Tim Peters6272dfd2001-12-13 19:34:00 +0000685What's New in Python 2.2c1?
686Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000687===========================
688
689Type/class unification and new-style classes
690
Barry Warsaw06557452001-12-14 20:47:12 +0000691- Guido's tutorial introduction to the new type/class features has
692 been extensively updated. See
693
694 http://www.python.org/2.2/descrintro.html
695
696 That remains the primary documentation in this area.
697
Guido van Rossum33bab012001-12-05 22:45:48 +0000698- Fixed a leak: instance variables declared with __slots__ were never
699 deleted!
700
Guido van Rossum4b800852001-12-03 00:54:52 +0000701- The "delete attribute" method of descriptor objects is called
702 __delete__, not __del__. In previous releases, it was mistakenly
703 called __del__, which created an unfortunate overloading condition
704 with finalizers. (The "get attribute" and "set attribute" methods
705 are still called __get__ and __set__, respectively.)
706
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000707- Some subtle issues with the super built-in were fixed:
708
709 (a) When super itself is subclassed, its __get__ method would still
710 return an instance of the base class (i.e., of super).
711
712 (b) super(C, C()).__class__ would return C rather than super. This
713 is confusing. To fix this, I decided to change the semantics of
714 super so that it only applies to code attributes, not to data
715 attributes. After all, overriding data attributes is not
716 supported anyway.
717
718 (c) The __get__ method didn't check whether the argument was an
719 instance of the type used in creation of the super instance.
720
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000721- Previously, hash() of an instance of a subclass of a mutable type
722 (list or dictionary) would return some value, rather than raising
723 TypeError. This has been fixed. Also, directly calling
724 dict.__hash__ and list.__hash__ now raises the same TypeError
725 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000726
Guido van Rossumd331cb52001-12-05 19:46:42 +0000727- New-style objects now support deleting their __dict__. This is for
728 all intents and purposes equivalent to assigning a brand new empty
729 dictionary, but saves space if the object is not used further.
730
Tim Petersb3c9af12001-11-17 00:21:57 +0000731Core and builtins
732
Tim Peters3caca232001-12-06 06:23:26 +0000733- -Qnew now works as documented in PEP 238: when -Qnew is passed on
734 the command line, all occurrences of "/" use true division instead
735 of classic division. See the PEP for details. Note that "all"
736 means all instances in library and 3rd-party modules, as well as in
737 your own code. As the PEP says, -Qnew is intended for use only in
738 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000739 Note that test_coercion.py in the standard Python test suite fails
740 under -Qnew; this is expected, and won't be repaired until true
741 division becomes the default (in the meantime, test_coercion is
742 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000743
Fred Drake6c01e252001-12-14 17:08:12 +0000744- complex() now only allows the first argument to be a string
745 argument, and raises TypeError if either the second arg is a string
746 or if the second arg is specified when the first is a string.
747
Tim Petersb3c9af12001-11-17 00:21:57 +0000748Extension modules
749
Martin v. Löwis560da622001-11-24 09:24:51 +0000750- gc.get_referents was renamed to gc.get_referrers.
751
Tim Petersb3c9af12001-11-17 00:21:57 +0000752Library
753
Tim Peters25059d32001-12-07 20:35:43 +0000754- Functions in the os.spawn() family now release the global interpreter
755 lock around calling the platform spawn. They should always have done
756 this, but did not before 2.2c1. Multithreaded programs calling
757 an os.spawn function with P_WAIT will no longer block all Python threads
758 until the spawned program completes. It's possible that some programs
759 relies on blocking, although more likely by accident than by design.
760
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000761- webbrowser defaults to netscape.exe on OS/2 now.
762
Martin v. Löwis652e1912001-11-25 14:50:56 +0000763- Tix.ResizeHandle exposes detach_widget, hide, and show.
764
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000765- The charset alias windows_1252 has been added.
766
Barry Warsaw06557452001-12-14 20:47:12 +0000767- types.StringTypes is a tuple containing the defined string types;
768 usually this will be (str, unicode), but if Python was compiled
769 without Unicode support it will be just (str,).
770
771- The pulldom and minidom modules were synchronized to PyXML.
772
Tim Petersb3c9af12001-11-17 00:21:57 +0000773Tools/Demos
774
Barry Warsaw06557452001-12-14 20:47:12 +0000775- A new script called Tools/scripts/google.py was added, which fires
776 off a search on Google.
777
Tim Petersb3c9af12001-11-17 00:21:57 +0000778Build
779
Barry Warsaw06557452001-12-14 20:47:12 +0000780- Note that release builds of Python should arrange to define the
781 preprocessor symbol NDEBUG on the command line (or equivalent).
782 In the 2.2 pre-release series we tried to define this by magic in
783 Python.h instead, but it proved to cause problems for extension
784 authors. The Unix, Windows and Mac builds now all define NDEBUG in
785 release builds via cmdline (or equivalent) instead. Ports to
786 other platforms should do likewise.
787
Jack Jansen1999ef42001-12-06 21:47:20 +0000788- It is no longer necessary to use --with-suffix when building on a
789 case-insensitive file system (such as Mac OS X HFS+). In the build
790 directory an extension is used, but not in the installed python.
791
Tim Petersb3c9af12001-11-17 00:21:57 +0000792C API
793
Tim Petersf582b822001-12-11 18:51:08 +0000794- New function PyDict_MergeFromSeq2() exposes the builtin dict
795 constructor's logic for updating a dictionary from an iterable object
796 producing key-value pairs.
797
Tim Peterscffed4b2001-11-29 03:26:37 +0000798- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000799 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000800 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
801 dump core in some bad cases. This has been repaired. As a result,
802 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
803 previously went unchallenged.
804
Tim Petersb3c9af12001-11-17 00:21:57 +0000805New platforms
806
807Tests
808
809Windows
810
811Mac
812
Jack Jansenffa260f2001-12-06 21:14:00 +0000813- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
814 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000815
Barry Warsaw06557452001-12-14 20:47:12 +0000816- Changed logic for finding python home in Mac OS X framework Pythons.
817 Now sys.executable points to the executable again, in stead of to
818 the shared library. The latter is used only for locating the python
819 home.
820
821
Tim Peters84362bc2001-10-19 17:55:30 +0000822What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000823Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000824===========================
825
826Type/class unification and new-style classes
827
Guido van Rossum3d27df02001-11-15 20:27:54 +0000828- Multiple inheritance mixing new-style and classic classes in the
829 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000830
831 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000832 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000833
834 The MRO (method resolution order) for each base class is respected
835 according to its kind, but the MRO for the derived class is computed
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000836 using new-style MRO rules if any base class is a new-style class.
Tim Peters76f7fe32001-11-15 20:02:21 +0000837 This needs to be documented.
838
Tim Petersa427a2b2001-10-29 22:25:45 +0000839- The new builtin dictionary() constructor, and dictionary type, have
840 been renamed to dict. This reflects a decade of common usage.
841
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000842- dict() now accepts an iterable object producing 2-sequences. For
843 example, dict(d.items()) == d for any dictionary d. The argument,
844 and the elements of the argument, can be any iterable objects.
845
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000846- New-style classes can now have a __del__ method, which is called
847 when the instance is deleted (just like for classic classes).
848
Guido van Rossum12d955c2001-10-26 14:56:06 +0000849- Assignment to object.__dict__ is now possible, for objects that are
850 instances of new-style classes that have a __dict__ (unless the base
851 class forbids it).
852
Guido van Rossumc8e56452001-10-22 00:43:43 +0000853- Methods of built-in types now properly check for keyword arguments
854 (formerly these were silently ignored). The only built-in methods
855 that take keyword arguments are __call__, __init__ and __new__.
856
Guido van Rossum86443212001-10-27 22:28:54 +0000857- The socket function has been converted to a type; see below.
858
Tim Peters84362bc2001-10-19 17:55:30 +0000859Core and builtins
860
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000861- Assignment to __debug__ raises SyntaxError at compile-time. This
862 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000863 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000864
Guido van Rossum12d955c2001-10-26 14:56:06 +0000865- Clarified the error messages for unsupported operands to an operator
866 (like 1 + '').
867
Tim Peters84362bc2001-10-19 17:55:30 +0000868Extension modules
869
Tim Peters5ebfd362001-11-13 23:11:19 +0000870- mmap has a new keyword argument, "access", allowing a uniform way for
871 both Windows and Unix users to create read-only, write-through and
872 copy-on-write memory mappings. This was previously possible only on
873 Unix. A new keyword argument was required to support this in a
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000874 uniform way because the mmap() signatures had diverged across
Tim Peters5ebfd362001-11-13 23:11:19 +0000875 platforms. Thanks to Jay T Miller for repairing this!
876
Tim Peters169ded02001-11-03 19:57:21 +0000877- By default, the gc.garbage list now contains only those instances in
878 unreachable cycles that have __del__ methods; in 2.1 it contained all
879 instances in unreachable cycles. "Instances" here has been generalized
880 to include instances of both new-style and old-style classes.
881
Guido van Rossum12d955c2001-10-26 14:56:06 +0000882- The socket module defines a new method for socket objects,
883 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000884 send() until all data has been sent. Also, the socket function has
885 been converted to a subclassable type, like list and tuple (etc.)
886 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000887
888- Various bugfixes to the curses module. There is now a test suite
889 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000890
Guido van Rossum692adf12001-10-30 03:03:03 +0000891- binascii.b2a_base64 no longer places an arbitrary restriction of 57
892 bytes on its input.
893
Tim Peters84362bc2001-10-19 17:55:30 +0000894Library
895
Tim Peters5ebfd362001-11-13 23:11:19 +0000896- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000897 convenience function.
898
Tim Peters75335872001-11-03 19:35:43 +0000899- Symbolic group names in regular expressions must be unique. For
900 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
901 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000902 Python 2.2 detects this error at regexp compilation time;
903 previously, the error went undetected, and results were
904 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
905 pattern.subn() methods have been rewritten in C. Also, an
906 experimental function/method finditer() has been added, which works
907 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000908
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000909- Tix exposes more commands through the classes DirSelectBox,
910 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
911 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
912 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
913
Tim Peters98791af2001-10-23 01:59:54 +0000914- Traceback objects are now scanned by cyclic garbage collection, so
915 cycles created by casual use of sys.exc_info() no longer cause
916 permanent memory leaks (provided garbage collection is enabled).
917
Guido van Rossum49192142001-10-24 20:51:44 +0000918- os.extsep -- a new variable needed by the RISCOS support. It is the
919 separator used by extensions, and is '.' on all platforms except
920 RISCOS, where it is '/'. There is no need to use this variable
921 unless you have a masochistic desire to port your code to RISCOS.
922
Barry Warsaw012852b2001-11-16 16:17:27 +0000923- mimetypes.py has optional support for non-standard, but commonly
924 found types. guess_type() and guess_extension() now accept an
925 optional `strict' flag, defaulting to true, which controls whether
926 recognize non-standard types or not. A few non-standard types we
927 know about have been added. Also, when run as a script, there are
928 new -l and -e options.
929
930- statcache is now deprecated.
931
932- email.Utils.formatdate() now produces the preferred RFC 2822 style
933 dates with numeric timezones (it used to produce obsolete dates
934 hard coded to "GMT" timezone). An optional `localtime' flag is
935 added to produce dates in the local timezone, with daylight savings
936 time properly taken into account.
937
938- In pickle and cPickle, instead of masking errors in load() by
939 transforming them into SystemError, we let the original exception
940 propagate out. Also, implement support for __safe_for_unpickling__
941 in pickle, as it already was supported in cPickle.
942
Tim Peters84362bc2001-10-19 17:55:30 +0000943Tools/Demos
944
945Build
946
Barry Warsaw012852b2001-11-16 16:17:27 +0000947- The dbm module is built using libdb1 if available. The bsddb module
948 is built with libdb3 if available.
949
950- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
951
Tim Peters84362bc2001-10-19 17:55:30 +0000952C API
953
Tim Peters1fc240e2001-10-26 05:06:50 +0000954- New function PySequence_Fast_GET_SIZE() returns the size of a non-
955 NULL result from PySequence_Fast(), more quickly than calling
956 PySequence_Size().
957
Barry Warsaw012852b2001-11-16 16:17:27 +0000958- New argument unpacking function PyArg_UnpackTuple() added.
959
960- New functions PyObject_CallFunctionObjArgs() and
961 PyObject_CallMethodObjArgs() have been added to make it more
962 convenient and efficient to call functions and methods from C.
963
964- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
965 possible that this will propagate errors it didn't before.
966
967- New function PyObject_CheckReadBuffer(), which returns true if its
968 argument supports the single-segment readable buffer interface.
969
Tim Peters84362bc2001-10-19 17:55:30 +0000970New platforms
971
Guido van Rossum86443212001-10-27 22:28:54 +0000972- We've finally confirmed that this release builds on HP-UX 11.00,
973 *with* threads, and passes the test suite.
974
Tim Peters7a33d8b2001-11-05 02:51:07 +0000975- Thanks to a series of patches from Michael Muller, Python may build
976 again under OS/2 Visual Age C++.
977
Guido van Rossum49192142001-10-24 20:51:44 +0000978- Updated RISCOS port by Dietmar Schwertberger.
979
Tim Peters84362bc2001-10-19 17:55:30 +0000980Tests
981
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000982- Added a test script for the curses module. It isn't run automatically;
983 regrtest.py must be run with '-u curses' to enable it.
984
Tim Peters84362bc2001-10-19 17:55:30 +0000985Windows
986
Barry Warsaw012852b2001-11-16 16:17:27 +0000987Mac
988
989- PythonScript has been moved to unsupported and is slated to be
990 removed completely in the next release.
991
992- It should now be possible to build applets that work on both OS9 and
993 OSX.
994
995- The core is now linked with CoreServices not Carbon; as a side
996 result, default 8bit encoding on OSX is now ASCII.
997
998- Python should now build on OSX 10.1.1
999
Tim Peters84362bc2001-10-19 17:55:30 +00001000
Tim Petersabf925f2001-09-28 21:53:42 +00001001What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +00001002Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +00001003===========================
1004
1005Type/class unification and new-style classes
1006
Guido van Rossum687ae002001-10-15 22:03:32 +00001007- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001008 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +00001009 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001010 remains: the __dict__ of a new-style class is a read-only proxy; you
1011 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +00001012 __defined__ attribute of new-style types no longer exists, for lack
1013 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001014 future a __cache__ may be resurrected with a similar function, if I
1015 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +00001016
Tim Peters1c9ca872001-10-04 06:43:12 +00001017- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
1018 always returned None, even when there was a class docstring).
1019
1020- doctest now finds and runs docstrings attached to new-style classes,
1021 class methods, static methods, and properties.
1022
Guido van Rossum9074ef62001-10-16 21:34:49 +00001023Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +00001024
Guido van Rossuma8bcf802001-10-15 15:53:58 +00001025- A very subtle syntactical pitfall in list comprehensions was fixed.
1026 For example: [a+b for a in 'abc', for b in 'def']. The comma in
1027 this example is a mistake. Previously, this would silently let 'a'
1028 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
1029 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
1030 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
1031 Note that [a for a in <singleton>] is a convoluted way to say
1032 [<singleton>] anyway, so it's not like any expressiveness is lost.
1033
Guido van Rossum9074ef62001-10-16 21:34:49 +00001034- getattr(obj, name, default) now only catches AttributeError, as
1035 documented, rather than returning the default value for all
1036 exceptions (which could mask bugs in a __getattr__ hook, for
1037 example).
1038
Fred Drakecb7a6b52001-10-22 18:41:51 +00001039- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +00001040 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001041 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +00001042 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +00001043
Guido van Rossum1c486092001-10-19 02:05:35 +00001044- unicode(obj) now behaves more like str(obj), accepting arbitrary
1045 objects, and calling a __unicode__ method if it exists.
1046 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +00001047 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +00001048
Barry Warsawf6fb1712001-10-19 05:35:40 +00001049- isinstance() now allows any object as the first argument and a
1050 class, a type or something with a __bases__ tuple attribute for the
1051 second argument. The second argument may also be a tuple of a
1052 class, type, or something with __bases__, in which case isinstance()
1053 will return true if the first argument is an instance of any of the
1054 things contained in the second argument tuple. E.g.
1055
1056 isinstance(x, (A, B))
1057
1058 returns true if x is an instance of A or B.
1059
Guido van Rossum9074ef62001-10-16 21:34:49 +00001060Extension modules
1061
1062- thread.start_new_thread() now returns the thread ID (previously None).
1063
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001064- binascii has now two quopri support functions, a2b_qp and b2a_qp.
1065
Guido van Rossumc524d952001-10-19 01:31:59 +00001066- readline now supports setting the startup_hook and the
1067 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +00001068
Guido van Rossumc524d952001-10-19 01:31:59 +00001069- os and posix supports chroot(), setgroups() and unsetenv() where
1070 available. The stat(), fstat(), statvfs() and fstatvfs() functions
1071 now return "pseudo-sequences" -- the various fields can now be
1072 accessed as attributes (e.g. os.stat("/").st_mtime) but for
1073 backwards compatibility they also behave as a fixed-length sequence.
1074 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +00001075 attributes.
1076
1077- time: localtime(), gmtime() and strptime() now return a
1078 pseudo-sequence similar to the os.stat() return value, with
1079 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +00001080
Guido van Rossum9074ef62001-10-16 21:34:49 +00001081- Decompression objects in the zlib module now accept an optional
1082 second parameter to decompress() that specifies the maximum amount
1083 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +00001084
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001085- optional SSL support in the socket module now exports OpenSSL
1086 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
1087 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +00001088 automatically seed its PRNG. Also, the keyfile and certfile
1089 arguments to socket.ssl() are now optional.
1090
1091- posixmodule (and by extension, the os module on POSIX platforms) now
1092 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001093
Guido van Rossum9074ef62001-10-16 21:34:49 +00001094Library
Guido van Rossum3c288632001-10-16 21:13:49 +00001095
Tim Peters7402f792001-10-02 03:53:41 +00001096- doctest now excludes functions and classes not defined by the module
1097 being tested, thanks to Tim Hochberg.
1098
Fred Drakecb7a6b52001-10-22 18:41:51 +00001099- HotShot, a new profiler implemented using a C-based callback, has
1100 been added. This substantially reduces the overhead of profiling,
1101 but it is still quite preliminary. Support modules and
1102 documentation will be added in upcoming releases (before 2.2 final).
1103
Guido van Rossumc4b09b42001-10-04 10:19:00 +00001104- profile now produces correct output in situations where an exception
1105 raised in Python is cleared by C code (e.g. hasattr()). This used
1106 to cause wrong output, including spurious claims of recursive
1107 functions and attribution of time spent to the wrong function.
1108
Tim Peters0a1fc4e2001-10-07 03:12:08 +00001109 The code and documentation for the derived OldProfile and HotProfile
1110 profiling classes was removed. The code hasn't worked for years (if
1111 you tried to use them, they raised exceptions). OldProfile
1112 intended to reproduce the behavior of the profiler Python used more
1113 than 7 years ago, and isn't interesting anymore. HotProfile intended
1114 to provide a faster profiler (but producing less information), and
1115 that's a worthy goal we intend to meet via a different approach (but
1116 without losing information).
1117
Tim Peterscce092d2001-10-09 05:31:56 +00001118- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +00001119 a much better system-specific calibration constant. The constant can
1120 now be specified in an instance constructor, or as a Profile class or
1121 instance variable, instead of by editing profile.py's source code.
1122 Calibration must still be done manually (see the docs for the profile
1123 module).
1124
1125 Note that Profile.calibrate() must be overriden by subclasses.
1126 Improving the accuracy required exploiting detailed knowledge of
1127 profiler internals; the earlier method abstracted away the details
1128 and measured a simplified model instead, but consequently computed
1129 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +00001130
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001131- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +00001132 which indicates whether output is intended for the header 'Q'
1133 encoding.
1134
Guido van Rossuma5343cc2001-10-18 18:02:07 +00001135- The SocketServer.ThreadingMixIn class now closes the request after
1136 finish_request() returns. (Not when it errors out though.)
1137
Barry Warsawf6fb1712001-10-19 05:35:40 +00001138- The nntplib module's NNTP.body() method has grown a `file' argument
1139 to allow saving the message body to a file.
1140
1141- The email package has added a class email.Parser.HeaderParser which
1142 only parses headers and does not recurse into the message's body.
1143 Also, the module/class MIMEAudio has been added for representing
1144 audio data (contributed by Anthony Baxter).
1145
1146- ftplib should be able to handle files > 2GB.
1147
1148- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
1149 ON, and OFF.
1150
Fred Drakecb7a6b52001-10-22 18:41:51 +00001151- xml.dom.minidom NodeList objects now support the length attribute
1152 and item() method as required by the DOM specifications.
1153
Guido van Rossumed554f62001-10-02 23:15:37 +00001154Tools/Demos
1155
1156- Demo/dns was removed. It no longer serves any purpose; a package
1157 derived from it is now maintained by Anthony Baxter, see
1158 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +00001159
Barry Warsawf6fb1712001-10-19 05:35:40 +00001160- The freeze tool has been made more robust, and two new options have
1161 been added: -X and -E.
1162
Tim Petersabf925f2001-09-28 21:53:42 +00001163Build
1164
Barry Warsawf6fb1712001-10-19 05:35:40 +00001165- configure will use CXX in LINKCC if CXX is used to build main() and
1166 the system requires to link a C++ main using the C++ compiler.
1167
Tim Petersabf925f2001-09-28 21:53:42 +00001168C API
1169
Guido van Rossum6c4bce32001-10-18 19:20:25 +00001170- The documentation for the tp_compare slot is updated to require that
1171 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
1172 not correct. This is not yet enforced but will be enforced in
1173 Python 2.3; even later, we may use -2 to indicate errors and +2 for
1174 "NotImplemented". Right now, -1 should be used for an error return.
1175
Tim Petersd38b1c72001-09-30 05:09:37 +00001176- PyLong_AsLongLong() now accepts int (as well as long) arguments.
1177 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
1178 as long) arguments.
1179
Guido van Rossum3c288632001-10-16 21:13:49 +00001180- PyThread_start_new_thread() now returns a long int giving the thread
1181 ID, if one can be calculated; it returns -1 for error, 0 if no
1182 thread ID is calculated (this is an incompatible change, but only
1183 the thread module used this API). This code has only really been
1184 tested on Linux and Windows; other platforms please beware (and
1185 report any bugs or strange behavior).
1186
Guido van Rossum1c486092001-10-19 02:05:35 +00001187- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
1188 input.
1189
Tim Petersabf925f2001-09-28 21:53:42 +00001190New platforms
1191
1192Tests
1193
1194Windows
1195
Tim Peters04cf1d32001-10-09 22:39:40 +00001196- Installer: If you install IDLE, and don't disable file-extension
1197 registration, a new "Edit with IDLE" context (right-click) menu entry
1198 is created for .py and .pyw files.
1199
Tim Peters1ce3cf72001-10-01 17:58:40 +00001200- The signal module now supports SIGBREAK on Windows, thanks to Steven
1201 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
1202 action remains to call Win32 ExitProcess(). This can be changed via
1203 signal.signal(). For example:
1204
1205 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
1206 # (SIGINT) behavior.
1207 import signal
1208 signal.signal(signal.SIGBREAK,
1209 signal.default_int_handler)
1210
1211 try:
1212 while 1:
1213 pass
1214 except KeyboardInterrupt:
1215 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
1216 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
1217 # program without the possibility for any Python-level cleanup).
1218 print "Clean exit"
1219
Tim Petersabf925f2001-09-28 21:53:42 +00001220
Tim Petersb07352e2001-09-08 01:25:47 +00001221What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001222Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +00001223===========================
1224
Guido van Rossum808eea72001-09-25 04:15:41 +00001225Type/class unification and new-style classes
1226
1227- pydoc and inspect are now aware of new-style classes;
1228 e.g. help(list) at the interactive prompt now shows proper
1229 documentation for all operations on list objects.
1230
1231- Applications using Jim Fulton's ExtensionClass module can now safely
1232 be used with Python 2.2. In particular, Zope 2.4.1 now works with
1233 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
1234 examples also work again. It is hoped that Gtk and Boost also work
1235 with 2.2a4 and beyond. (If you can confirm this, please write
1236 webmaster@python.org; if there are still problems, please open a bug
1237 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +00001238
Tim Peters66c1a522001-09-24 21:17:50 +00001239- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001240 These map to read-only attributes 'fget', 'fset', 'fdel', and '__doc__'
Tim Peters66c1a522001-09-24 21:17:50 +00001241 in the constructed property object. fget, fset and fdel weren't
1242 discoverable from Python in 2.2a3. __doc__ is new, and allows to
1243 associate a docstring with a property.
1244
Guido van Rossum808eea72001-09-25 04:15:41 +00001245- Comparison overloading is now more completely implemented. For
1246 example, a str subclass instance can properly be compared to a str
1247 instance, and it can properly overload comparison. Ditto for most
1248 other built-in object types.
1249
1250- The repr() of new-style classes has changed; instead of <type
1251 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
1252 *except* for built-in types, which are still rendered as <type
1253 'Foo'> (to avoid upsetting existing code that might parse or
1254 otherwise rely on repr() of certain type objects).
1255
1256- The repr() of new-style objects is now always <Foo object at XXX>;
1257 previously, it was sometimes <Foo instance at XXX>.
1258
1259- For new-style classes, what was previously called __getattr__ is now
1260 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001261 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +00001262 one in classic classes is defined which is called only if regular
1263 attribute access raises AttributeError; to catch *all* attribute
1264 access, you can use __getattribute__ (for new-style classes). If
1265 both are defined, __getattribute__ is called first, and if it raises
1266 AttributeError, __getattr__ is called.
1267
1268- The __class__ attribute of new-style objects can be assigned to.
1269 The new class must have the same C-level object layout as the old
1270 class.
1271
1272- The builtin file type can be subclassed now. In the usual pattern,
1273 "file" is the name of the builtin type, and file() is a new builtin
1274 constructor, with the same signature as the builtin open() function.
1275 file() is now the preferred way to open a file.
1276
1277- Previously, __new__ would only see sequential arguments passed to
1278 the type in a constructor call; __init__ would see both sequential
1279 and keyword arguments. This made no sense whatsoever any more, so
1280 now both __new__ and __init__ see all arguments.
1281
1282- Previously, hash() applied to an instance of a subclass of str or
1283 unicode always returned 0. This has been repaired.
1284
1285- Previously, an operation on an instance of a subclass of an
1286 immutable type (int, long, float, complex, tuple, str, unicode),
1287 where the subtype didn't override the operation (and so the
1288 operation was handled by the builtin type), could return that
1289 instance instead a value of the base type. For example, if s was of
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001290 a str subclass type, s[:] returned s as-is. Now it returns a str
Guido van Rossum808eea72001-09-25 04:15:41 +00001291 with the same value as s.
1292
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001293- Provisional support for pickling new-style objects has been added.
1294
Guido van Rossum808eea72001-09-25 04:15:41 +00001295Core
1296
Tim Peters2c9aa5e2001-09-23 04:06:05 +00001297- file.writelines() now accepts any iterable object producing strings.
1298
Marc-André Lemburgaefd7662001-09-20 12:59:37 +00001299- PyUnicode_FromEncodedObject() now works very much like
1300 PyObject_Str(obj) in that it tries to use __str__/tp_str
1301 on the object if the object is not a string or buffer. This
1302 makes unicode() behave like str() when applied to non-string/buffer
1303 objects.
1304
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001305- PyFile_WriteObject now passes Unicode objects to the file's write
1306 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +00001307 of a print statement must support Unicode objects, i.e. they must
1308 at least convert them into ASCII strings.
1309
Guido van Rossum624c8af2001-09-18 15:21:04 +00001310- Thread scheduling on Solaris should be improved; it is no longer
1311 necessary to insert a small sleep at the start of a thread in order
1312 to let other runnable threads be scheduled.
1313
Tim Petersb07352e2001-09-08 01:25:47 +00001314Library
1315
Marc-André Lemburgbf990172001-09-27 14:17:33 +00001316- StringIO.StringIO instances and cStringIO.StringIO instances support
1317 read character buffer compatible objects for their .write() methods.
1318 These objects are converted to strings and then handled as such
1319 by the instances.
1320
Barry Warsaw2f600732001-09-24 04:28:10 +00001321- The "email" package has been added. This is basically a port of the
1322 mimelib package <http://sf.net/projects/mimelib> with API changes
1323 and some implementations updated to use iterators and generators.
1324
Tim Peters8a9c2842001-09-22 21:30:22 +00001325- difflib.ndiff() and difflib.Differ.compare() are generators now. This
1326 restores the ability of Tools/scripts/ndiff.py to start producing output
1327 before the entire comparison is complete.
1328
Barry Warsaw58b072d2001-09-22 04:44:21 +00001329- StringIO.StringIO instances and cStringIO.StringIO instances support
1330 iteration just like file objects (i.e. their .readline() method is
1331 called for each iteration until it returns an empty string).
1332
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +00001333- The codecs module has grown four new helper APIs to access
1334 builtin codecs: getencoder(), getdecoder(), getreader(),
1335 getwriter().
1336
Guido van Rossum624c8af2001-09-18 15:21:04 +00001337- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
1338 simplifies writing XML RPC servers.
1339
Barry Warsaw647d5e82001-09-28 17:01:02 +00001340- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +00001341 after interpretation of symbolic links. On non-Unix systems, this
1342 is an alias for os.path.abspath().
1343
Tim Peters16a77ad2001-09-08 04:00:12 +00001344- operator.indexOf() (PySequence_Index() in the C API) now works with any
1345 iterable object.
1346
Guido van Rossum624c8af2001-09-18 15:21:04 +00001347- smtplib now supports various authentication and security features of
1348 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001349
Guido van Rossum624c8af2001-09-18 15:21:04 +00001350- hmac: a new module implementing keyed hashing for message
1351 authentication.
1352
1353- mimetypes now recognizes more extensions and file types. At the
1354 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001355
Guido van Rossum624c8af2001-09-18 15:21:04 +00001356- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001357 Python 2.2 bytecode generation. It has also been promoted from a
1358 Tool to a standard library package. (Tools/compiler still exists as
1359 a sample driver.)
1360
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001361Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +00001362
Tim Petersb07352e2001-09-08 01:25:47 +00001363Build
1364
Guido van Rossum624c8af2001-09-18 15:21:04 +00001365- Large file support (LFS) is now automatic when the platform supports
1366 it; no more manual configuration tweaks are needed. On Linux, at
1367 least, it's possible to have a system whose C library supports large
1368 files but whose kernel doesn't; in this case, large file support is
1369 still enabled but doesn't do you any good unless you upgrade your
1370 kernel or share your Python executable with another system whose
1371 kernel has large file support.
1372
1373- The configure script now supplies plausible defaults in a
1374 cross-compilation environment. This doesn't mean that the supplied
1375 values are always correct, or that cross-compilation now works
1376 flawlessly -- but it's a first step (and it shuts up most of
1377 autoconf's warnings about AC_TRY_RUN).
1378
1379- The Unix build is now a bit less chatty, courtesy of the parser
1380 generator. The build is completely silent (except for errors) when
1381 using "make -s", thanks to a -q option to setup.py.
1382
Tim Petersb07352e2001-09-08 01:25:47 +00001383C API
1384
Guido van Rossum624c8af2001-09-18 15:21:04 +00001385- The "structmember" API now supports some new flag bits to deny read
1386 and/or write access to attributes in restricted execution mode.
1387
Tim Petersb07352e2001-09-08 01:25:47 +00001388New platforms
1389
Guido van Rossum624c8af2001-09-18 15:21:04 +00001390- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1391 (http://familiar.handhelds.org).
1392
Tim Petersb07352e2001-09-08 01:25:47 +00001393Tests
1394
Tim Peters8a9c2842001-09-22 21:30:22 +00001395- The "classic" standard tests, which work by comparing stdout to
1396 an expected-output file under Lib/test/output/, no longer stop at
1397 the first mismatch. Instead the test is run to completion, and a
1398 variant of ndiff-style comparison is used to report all differences.
1399 This is much easier to understand than the previous style of reporting.
1400
1401- The unittest-based standard tests now use regrtest's test_main()
1402 convention, instead of running as a side-effect of merely being
1403 imported. This allows these tests to be run in more natural and
1404 flexible ways as unittests, outside the regrtest framework.
1405
1406- regrtest.py is much better integrated with unittest and doctest now,
1407 especially in regard to reporting errors.
1408
Tim Petersb07352e2001-09-08 01:25:47 +00001409Windows
1410
Guido van Rossum624c8af2001-09-18 15:21:04 +00001411- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001412 that support it (NTFS under Windows 2000). See "What's New in
1413 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001414
Tim Petersb07352e2001-09-08 01:25:47 +00001415
Tim Petersedc99312001-08-22 21:36:50 +00001416What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001417Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001418===========================
1419
1420Core
1421
Tim Peters9fffa3e2001-09-04 05:14:19 +00001422- Conversion of long to float now raises OverflowError if the long is too
1423 big to represent as a C double.
1424
Tim Peters32f453e2001-09-03 08:35:41 +00001425- The 3-argument builtin pow() no longer allows a third non-None argument
1426 if either of the first two arguments is a float, or if both are of
1427 integer types and the second argument is negative (in which latter case
1428 the arguments are converted to float, so this is really the same
1429 restriction).
1430
Tim Peters5d2b77c2001-09-03 05:47:38 +00001431- The builtin dir() now returns more information, and sometimes much
1432 more, generally naming all attributes of an object, and all attributes
1433 reachable from the object via its class, and from its class's base
1434 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1435 an empty list. In 2.2a3,
1436
1437 >>> dir([])
1438 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1439 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1440 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1441 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1442 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1443 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1444 'reverse', 'sort']
1445
1446 dir(module) continues to return only the module's attributes, though.
1447
Tim Petersbdee63f2001-09-02 03:40:59 +00001448- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001449 than raising OverflowError. This is a partial implementation of PEP
1450 237. You can use -Wdefault::OverflowWarning to enable a warning for
1451 this situation, and -Werror::OverflowWarning to revert to the old
1452 OverflowError exception.
1453
Guido van Rossum61c345f2001-09-04 03:26:15 +00001454- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001455 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001456 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1457 -Qold, meaning the / operator has its classic meaning and no
1458 warnings are issued. Using -Qwarn issues a run-time warning about
1459 all uses of classic division for int and long arguments; -Qwarnall
1460 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001461 (for use with fixdiv.py).
1462 [Note: the remainder of this paragraph (preserved below) became
1463 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1464 <obsolete>
1465 Using -Qnew is questionable; it turns on new division by default, but
1466 only in the __main__ module. You can usefully combine -Qwarn or
1467 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1468 warns about classic division everywhere else.
1469 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001470
Tim Petersbdee63f2001-09-02 03:40:59 +00001471- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001472 long, float, str, unicode, and tuple. (The types complex, list and
1473 dictionary can also be subclassed; this was introduced earlier.)
1474 Note that restrictions apply when subclassing immutable built-in
1475 types: you can only affect the value of the instance by overloading
1476 __new__. You can add mutable attributes, and the subclass instances
1477 will have a __dict__ attribute, but you cannot change the "value"
1478 (as implemented by the base class) of an immutable subclass instance
1479 once it is created.
1480
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001481- The dictionary constructor now takes an optional argument, a
1482 mapping-like object, and initializes the dictionary from its
1483 (key, value) pairs.
1484
Tim Petersbdee63f2001-09-02 03:40:59 +00001485- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001486 "cooperative super calls" in a multiple inheritance setting. For an
1487 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1488
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001489- A new built-in type, property, has been added. This enables the
1490 creation of "properties". These are attributes implemented by
1491 getter and setter functions (or only one of these for read-only or
1492 write-only attributes), without the need to override __getattr__.
1493 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001494
Tim Petersbdee63f2001-09-02 03:40:59 +00001495- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001496 liberalized, to allow leading zeroes. Examples of literals now
1497 legal that were SyntaxErrors before:
1498
1499 00.0 0e3 0100j 07.5 00000000000000000008.
1500
Tim Petersbdee63f2001-09-02 03:40:59 +00001501- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001502 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1503
Tim Petersedc99312001-08-22 21:36:50 +00001504Library
1505
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001506- telnetlib includes symbolic names for the options, and support for
1507 setting an option negotiation callback.
1508
Tim Petersa40c7932001-09-05 22:36:56 +00001509- The new C standard no longer requires that math libraries set errno to
1510 ERANGE on overflow. For platform libraries that exploit this new
1511 freedom, Python's overflow-checking was wholly broken. A new overflow-
1512 checking scheme attempts to repair that, but may not be reliable on all
1513 platforms (C doesn't seem to provide anything both useful and portable
1514 in this area anymore).
1515
Martin v. Löwis44f86962001-09-05 13:44:54 +00001516- Asynchronous timeout actions are available through the new class
1517 threading.Timer.
1518
Tim Peters78526162001-09-05 00:53:45 +00001519- math.log and math.log10 now return sensible results for even huge
1520 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1521
Tim Petersbdee63f2001-09-02 03:40:59 +00001522- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001523 currently held. See the docs for the imp module.
1524
Tim Petersbdee63f2001-09-02 03:40:59 +00001525- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001526 dumps containing ints written on platforms where Python ints are 8 bytes.
1527 When read on a box where Python ints are 4 bytes, such values are
1528 converted to Python longs.
1529
Tim Petersbdee63f2001-09-02 03:40:59 +00001530- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001531 code objects is no longer allowed. This plugs a security hole.
1532
Steve Purcell6091cd62001-09-06 16:05:17 +00001533- unittest.TestResult instances no longer store references to tracebacks
1534 generated by test failures. This prevents unexpected dangling references
1535 to objects that should be garbage collected between tests.
1536
Tim Petersedc99312001-08-22 21:36:50 +00001537Tools
1538
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001539- Tools/scripts/fixdiv.py has been added which can be used to fix
1540 division operators as per PEP 238.
1541
Tim Petersedc99312001-08-22 21:36:50 +00001542Build
1543
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001544- If you are an adventurous person using Mac OS X you may want to look at
1545 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1546 application, which can be used for experimenting with Carbon or Cocoa.
1547 Discussion of this on pythonmac-sig, please.
1548
Tim Peters7eea37e2001-09-04 22:08:56 +00001549C API
1550
1551- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001552
Tim Peters9fffa3e2001-09-04 05:14:19 +00001553- Note that PyLong_AsDouble can fail! This has always been true, but no
1554 callers checked for it. It's more likely to fail now, because overflow
1555 errors are properly detected now. The proper way to check:
1556
1557 double x = PyLong_AsDouble(some_long_object);
1558 if (x == -1.0 && PyErr_Occurred()) {
1559 /* The conversion failed. */
1560 }
1561
Tim Petersbdee63f2001-09-02 03:40:59 +00001562- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001563 compile but will not participate in GC. To upgrade an extension
1564 module:
1565
1566 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001567
Neil Schemenauer4042c692001-08-30 15:38:01 +00001568 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1569 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001570
Neil Schemenauer4042c692001-08-30 15:38:01 +00001571 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1572 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001573
Neil Schemenauer4042c692001-08-30 15:38:01 +00001574 - remove PyGC_HEAD_SIZE from object size calculations
1575
1576 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1577
Tim Petersbdee63f2001-09-02 03:40:59 +00001578- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001579 These can be used safely to construct string objects from a
1580 sprintf-style format string (similar to the format string supported
1581 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001582
Tim Petersedc99312001-08-22 21:36:50 +00001583New platforms
1584
Tim Petersb7da0902001-09-02 23:01:43 +00001585- Stephen Hansen contributed patches sufficient to get a clean compile
1586 under Borland C (Windows), but he reports problems running it and ran
1587 out of time to complete the port. Volunteers? Expect a MemoryError
1588 when importing the types module; this is probably shallow, and
1589 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001590
Tim Petersedc99312001-08-22 21:36:50 +00001591Tests
1592
1593Windows
1594
Tim Peters6e13a562001-09-06 00:32:15 +00001595- Large file support is now enabled on Win32 platforms as well as on
1596 Win64. This means that, for example, you can use f.tell() and f.seek()
1597 to manipulate files larger than 2 gigabytes (provided you have enough
1598 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001599 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1600 filesize limit, and large file support makes no difference there.
1601 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1602 NTFS has no practical limit on file size, and files of any size can be
1603 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001604
Tim Petersbdee63f2001-09-02 03:40:59 +00001605- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001606 points to command.com (patch from Brian Quinlan).
1607
Tim Petersedc99312001-08-22 21:36:50 +00001608
Tim Peters20f51a72001-07-21 02:31:40 +00001609What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001610Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001611===========================
1612
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001613Build
1614
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001615- Tim Peters developed a brand new Windows installer using Wise 8.1,
1616 generously donated to us by Wise Solutions.
1617
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001618- configure supports a new option --enable-unicode, with the values
1619 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1620 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001621
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001622- A new configure option --enable-framework builds a Mac OS X framework,
1623 which "make frameworkinstall" will install. This provides a starting
1624 point for more mac-like functionality, join pythonmac-sig@python.org
1625 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001626
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001627- The NeXT platform is no longer supported.
1628
1629- The `new' module is now statically linked.
1630
Tim Peters0afb6092001-08-15 06:06:44 +00001631Tools
1632
1633- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001634 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001635 the module docstring for details.
1636
Tim Peters20f51a72001-07-21 02:31:40 +00001637Tests
1638
Tim Peters5e824c32001-08-12 22:25:01 +00001639- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001640 platforms, allowing to give clearer test result output. regrtest
1641 also has optional --use/-u switch to run normally disabled tests
1642 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001643
Tim Peters20f51a72001-07-21 02:31:40 +00001644- Several new tests in the standard test suite, with special thanks to
1645 Nick Mathewson.
1646
1647Core
1648
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001649- The floor division operator // has been added as outlined in PEP
1650 238. The / operator still provides classic division (and will until
1651 Python 3.0) unless "from __future__ import division" is included, in
1652 which case the / operator will provide true division. The operator
1653 module provides truediv() and floordiv() functions. Augmented
1654 assignment variants are included, as are the equivalent overloadable
1655 methods and C API methods. See the PEP for a full discussion:
1656 <http://python.sf.net/peps/pep-0238.html>
1657
Tim Peters6cd6a822001-08-17 22:11:27 +00001658- Future statements are now effective in simulated interactive shells
1659 (like IDLE). This should "just work" by magic, but read Michael
1660 Hudson's "Future statements in simulated shells" PEP 264 for full
1661 details: <http://python.sf.net/peps/pep-0264.html>.
1662
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001663- The type/class unification (PEP 252-253) was integrated into the
1664 trunk and is not so tentative any more (the exact specification of
1665 some features is still tentative). A lot of work has done on fixing
1666 bugs and adding robustness and features (performance still has to
1667 come a long way).
1668
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001669- Warnings about a mismatch in the Python API during extension import
1670 now use the Python warning framework (which makes it possible to
1671 write filters for these warnings).
1672
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001673- A function's __dict__ (aka func_dict) will now always be a
1674 dictionary. It used to be possible to delete it or set it to None,
1675 but now both actions raise TypeErrors. It is still legal to set it
1676 to a dictionary object. Getting func.__dict__ before any attributes
1677 have been assigned now returns an empty dictionary instead of None.
1678
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001679- A new command line option, -E, was added which disables the use of
1680 all environment variables, or at least those that are specifically
1681 significant to Python. Usually those have a name starting with
1682 "PYTHON". This was used to fix a problem where the tests fail if
1683 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1684 older distribution.
1685
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001686Library
1687
Tim Peters5e824c32001-08-12 22:25:01 +00001688- New class Differ and new functions ndiff() and restore() in difflib.py.
1689 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001690 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001691
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001692- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1693 value using the minimal quoting required for the value; more
1694 reliable than using xml.sax.saxutils.escape() for attribute values.
1695
1696- Readline completion support for cmd.Cmd was added.
1697
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001698- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1699
1700- Added function threading.BoundedSemaphore()
1701
1702- Added Ka-Ping Yee's cgitb.py module.
1703
1704- The `new' module now exposes the CO_xxx flags.
1705
Martin v. Löwis560da622001-11-24 09:24:51 +00001706- The gc module offers the get_referents function.
1707
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001708New platforms
1709
1710C API
1711
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001712- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1713 which provide a cross-platform implementations for the
1714 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1715 the standard sprintf() and vsprintf() C lib APIs, these versions
1716 apply bounds checking on the used buffer which enhances protection
1717 against buffer overruns.
1718
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001719- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001720 and extensions using different Unicode widths is rendered next to
1721 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001722 will result in an ImportError. Unicode extensions writers must make
1723 sure to check the Unicode width compatibility in their extensions by
1724 using at least one of the mangled Unicode APIs in the extension.
1725
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001726- Two new flags METH_NOARGS and METH_O are available in method definition
1727 tables to simplify implementation of methods with no arguments and a
1728 single untyped argument. Calling such methods is more efficient than
1729 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1730 deprecated.
1731
Tim Petersc1731372001-08-04 08:12:36 +00001732Windows
1733
1734- "import module" now compiles module.pyw if it exists and nothing else
1735 relevant is found.
1736
Tim Peters20f51a72001-07-21 02:31:40 +00001737
Guido van Rossum55a78992001-07-17 17:22:32 +00001738What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001739Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001740===========================
1741
1742Core
Tim Petersa814db52001-05-14 07:05:58 +00001743
Tim Peters6d6c1a32001-08-02 04:15:00 +00001744- TENTATIVELY, a large amount of code implementing much of what's
1745 described in PEP 252 (Making Types Look More Like Classes) and PEP
1746 253 (Subtyping Built-in Types) was added. This will be released
1747 with Python 2.2a1. Documentation will be provided separately
1748 through http://www.python.org/2.2/. The purpose of releasing this
1749 with Python 2.2a1 is to test backwards compatibility. It is
1750 possible, though not likely, that a decision is made not to release
1751 this code as part of 2.2 final, if any serious backwards
1752 incompapatibilities are found during alpha testing that cannot be
1753 repaired.
1754
Guido van Rossum55a78992001-07-17 17:22:32 +00001755- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001756 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001757 more 'yield' statements. See PEP 255. Since this adds a new
1758 keyword to the language, this feature must be enabled by including a
1759 future statement: "from __future__ import generators" (see PEP 236).
1760 Generators will become a standard feature in a future release
1761 (probably 2.3). Without this future statement, 'yield' remains an
1762 ordinary identifier, but a warning is issued each time it is used.
1763 (These warnings currently don't conform to the warnings framework of
1764 PEP 230; we intend to fix this in 2.2a2.)
1765
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001766- The UTF-16 codec was modified to be more RFC compliant. It will now
1767 only remove BOM characters at the start of the string and then
1768 only if running in native mode (UTF-16-LE and -BE won't remove a
1769 leading BMO character).
1770
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001771- Strings now have a new method .decode() to complement the already
1772 existing .encode() method. These two methods provide direct access
1773 to the corresponding decoders and encoders of the registered codecs.
1774
1775 To enhance the usability of the .encode() method, the special
1776 casing of Unicode object return values was dropped (Unicode objects
1777 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001778
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001779 Both methods will now return whatever the codec in charge of the
1780 requested encoding returns as object, e.g. Unicode codecs will
1781 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1782 will return u"äöü"). This enables codec writer to create codecs
1783 for various simple to use conversions.
1784
1785 New codecs were added to demonstrate these new features (the .encode()
1786 and .decode() columns indicate the type of the returned objects):
1787
1788 Name | .encode() | .decode() | Description
1789 ----------------------------------------------------------------------
1790 uu | string | string | UU codec (e.g. for email)
1791 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001792 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001793 zlib | string | string | zlib compression
1794 hex | string | string | 2-byte hex codec
1795 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1796
Mark Hammond2a0af792001-05-14 03:09:36 +00001797- Some operating systems now support the concept of a default Unicode
1798 encoding for file system operations. Notably, Windows supports 'mbcs'
1799 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001800 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001801 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001802
1803 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001804 functions that return filenames (such as os.listdir()) to return Python
1805 string objects pre-encoded using the default file system encoding for
1806 the platform. As this encoding is likely to be different from Python's
1807 default encoding, converting this name to a Unicode object before passing
1808 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001809 would attempt to use its default encoding (generally ASCII) rather than
1810 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001811
Tim Petersa814db52001-05-14 07:05:58 +00001812 In general, this change simply removes surprises when working with
1813 Unicode and the file system, making these operations work as you expect,
1814 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001815 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001816
Tim Peters61dff2b2001-05-08 15:43:37 +00001817- Float (and complex) literals in source code were evaluated to full
1818 precision only when running from a .py file; the same code loaded from a
1819 .pyc (or .pyo) file could suffer numeric differences starting at about the
1820 12th significant decimal digit. For example, on a machine with IEEE-754
1821 floating arithmetic,
1822
1823 x = 9007199254740992.0
1824 print long(x)
1825
1826 printed 9007199254740992 if run directly from .py, but 9007199254740000
1827 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1828 str(float) instead of repr(float) when building code objects. marshal
1829 now uses repr(float) instead, which should reproduce floats to full
1830 machine precision (assuming the platform C float<->string I/O conversion
1831 functions are of good quality).
1832
1833 This may cause floating-point results to change in some cases, and
1834 usually for the better, but may also cause numerically unstable
1835 algorithms to break.
1836
Tim Peters2f228e72001-05-13 00:19:31 +00001837- The implementation of dicts suffers fewer collisions, which has speed
1838 benefits. However, the order in which dict entries appear in dict.keys(),
1839 dict.values() and dict.items() may differ from previous releases for a
1840 given dict. Nothing is defined about this order, so no program should
1841 rely on it. Nevertheless, it's easy to write test cases that rely on the
1842 order by accident, typically because of printing the str() or repr() of a
1843 dict to an "expected results" file. See Lib/test/test_support.py's new
1844 sortdict(dict) function for a simple way to display a dict in sorted
1845 order.
1846
Tim Peters7a3bfc32001-06-12 01:22:22 +00001847- Many other small changes to dicts were made, resulting in faster
1848 operation along the most common code paths.
1849
Guido van Rossum10315822001-05-01 20:54:30 +00001850- Dictionary objects now support the "in" operator: "x in dict" means
1851 the same as dict.has_key(x).
1852
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001853- The update() method of dictionaries now accepts generic mapping
1854 objects. Specifically the argument object must support the .keys()
1855 and __getitem__() methods. This allows you to say, for example,
1856 {}.update(UserDict())
1857
Guido van Rossum10315822001-05-01 20:54:30 +00001858- Iterators were added; this is a generalized way of providing values
1859 to a for loop. See PEP 234. There's a new built-in function iter()
1860 to return an iterator. There's a new protocol to get the next value
1861 from an iterator using the next() method (in Python) or the
1862 tp_iternext slot (in C). There's a new protocol to get iterators
1863 using the __iter__() method (in Python) or the tp_iter slot (in C).
1864 Iterating (i.e. a for loop) over a dictionary generates its keys.
1865 Iterating over a file generates its lines.
1866
Tim Petersf553f892001-05-01 20:45:31 +00001867- The following functions were generalized to work nicely with iterator
1868 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001869 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001870 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1871 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001872 join() method of strings
1873 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001874 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1875 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001876 right-hand side of assignment statements with multiple targets, such as
1877 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001878
Tim Petersd85e1022001-05-11 21:51:48 +00001879- Accessing module attributes is significantly faster (for example,
1880 random.random or os.path or yourPythonModule.yourAttribute).
1881
Tim Peterse63415e2001-05-08 04:38:29 +00001882- Comparing dictionary objects via == and != is faster, and now works even
1883 if the keys and values don't support comparisons other than ==.
1884
Tim Peters95bf9392001-05-10 08:32:44 +00001885- Comparing dictionaries in ways other than == and != is slower: there were
1886 insecurities in the dict comparison implementation that could cause Python
1887 to crash if the element comparison routines for the dict keys and/or
1888 values mutated the dicts. Making the code bulletproof slowed it down.
1889
Tim Peterseb28ef22001-06-02 05:27:19 +00001890- Collisions in dicts are resolved via a new approach, which can help
1891 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001892 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001893 faster now. Thanks to Christian Tismer for pointing out the cause and
1894 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001895
Tim Peters52e155e2001-06-16 05:42:57 +00001896- repr() is much faster for large containers (dict, list, tuple).
1897
1898
Tim Petersa814db52001-05-14 07:05:58 +00001899Library
1900
Fred Drake960fdf92001-07-20 18:38:26 +00001901- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1902 were added to the string module. These a locale-indenpendent
1903 constants, unlike letters, lowercase, and uppercase. These are now
1904 use in appropriate locations in the standard library.
1905
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001906- The flags used in dlopen calls can now be configured using
1907 sys.setdlopenflags and queried using sys.getdlopenflags.
1908
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001909- Fredrik Lundh's xmlrpclib is now a standard library module. This
1910 provides full client-side XML-RPC support. In addition,
1911 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1912 one asyncore-based). Thanks to Eric Raymond for the documentation.
1913
Guido van Rossum643d3912001-07-05 14:46:25 +00001914- The xrange() object is simplified: it no longer supports slicing,
1915 repetition, comparisons, efficient 'in' checking, the tolist()
1916 method, or the start, stop and step attributes. See PEP 260.
1917
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001918- A new function fnmatch.filter to filter lists of file names was added.
1919
Barry Warsawffd674d2001-05-22 16:00:10 +00001920- calendar.py uses month and day names based on the current locale.
1921
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001922- strop is now *really* obsolete (this was announced before with 1.6),
1923 and issues DeprecationWarning when used (except for the four items
1924 that are still imported into string.py).
1925
Tim Petersa814db52001-05-14 07:05:58 +00001926- Cookie.py now sorts key+value pairs by key in output strings.
1927
1928- pprint.isrecursive(object) didn't correctly identify recursive objects.
1929 Now it does.
1930
Tim Peters95b3f782001-05-14 18:39:41 +00001931- pprint functions now much faster for large containers (tuple, list, dict).
1932
Tim Peters7b9542a2001-06-10 23:40:19 +00001933- New 'q' and 'Q' format codes in the struct module, corresponding to C
1934 types "long long" and "unsigned long long" (on Windows, __int64). In
1935 native mode, these can be used only when the platform C compiler supports
1936 these types (when HAVE_LONG_LONG is #define'd by the Python config
1937 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001938 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1939 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001940
Guido van Rossum83213cc2001-06-12 16:48:52 +00001941- The site module installs a new built-in function 'help' that invokes
1942 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1943 it displays a message reminding the user to use 'help()' or
1944 'help(object)'.
1945
Tim Petersa814db52001-05-14 07:05:58 +00001946Tests
1947
1948- New test_mutants.py runs dict comparisons where the key and value
1949 comparison operators mutute the dicts randomly during comparison. This
1950 rapidly causes Python to crash under earlier releases (not for the faint
1951 of heart: it can also cause Win9x to freeze or reboot!).
1952
1953- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001954 pprint.isreadable() return sensible results. Also verifies that simple
1955 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001956
Tim Peters4324aa32001-05-28 22:30:08 +00001957C API
1958
1959- Removed the unused last_is_sticky argument from the internal
1960 _PyTuple_Resize(). If this affects you, you were cheating.
1961
1962
Guido van Rossum55a78992001-07-17 17:22:32 +00001963======================================================================
1964
1965
Guido van Rossumffe13be2001-04-16 18:46:45 +00001966What's New in Python 2.1 (final)?
1967=================================
1968
1969We only changed a few things since the last release candidate, all in
1970Python library code:
1971
1972- A bug in the locale module was fixed that affected locales which
1973 define no grouping for numeric formatting.
1974
1975- A few bugs in the weakref module's implementations of weak
1976 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1977 and the test suite was updated to check for these bugs.
1978
1979- An old bug in the os.path.walk() function (introduced in Python
1980 2.0!) was fixed: a non-existent file would cause an exception
1981 instead of being ignored.
1982
1983- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1984 PyChecker.
1985
1986
Guido van Rossum5b08f132001-04-16 02:05:23 +00001987What's New in Python 2.1c2?
1988===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001989
Guido van Rossum5b08f132001-04-16 02:05:23 +00001990A flurry of small changes, and one showstopper fixed in the nick of
1991time made it necessary to release another release candidate. The list
1992here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001993
Guido van Rossum5b08f132001-04-16 02:05:23 +00001994Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001995
Guido van Rossum5b08f132001-04-16 02:05:23 +00001996- Tim discovered a nasty bug in the dictionary code, caused by
1997 PyDict_Next() calling dict_resize(), and the GC code's use of
1998 PyDict_Next() violating an assumption in dict_items(). This was
1999 fixed with considerable amounts of band-aid, but the net effect is a
2000 saner and more robust implementation.
2001
2002- Made a bunch of symbols static that were accidentally global.
2003
2004Build and Ports
2005
2006- The setup.py script didn't check for a new enough version of zlib
2007 (1.1.3 is needed). Now it does.
2008
2009- Changed "make clean" target to also remove shared libraries.
2010
2011- Added a more general warning about the SGI Irix optimizer to README.
2012
2013Library
2014
2015- Fix a bug in urllib.basejoin("http://host", "../file.html") which
2016 omitted the slash between host and file.html.
2017
2018- The mailbox module's _Mailbox class contained a completely broken
2019 and undocumented seek() method. Ripped it out.
2020
2021- Fixed a bunch of typos in various library modules (urllib2, smtpd,
2022 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
2023
2024- Fixed a few last-minute bugs in unittest.
2025
2026Extensions
2027
2028- Reverted the patch to the OpenSSL code in socketmodule.c to support
2029 RAND_status() and the EGD, and the subsequent patch that tried to
2030 fix it for pre-0.9.5 versions; the problem with the patch is that on
2031 some systems it issues a warning whenever socket is imported, and
2032 that's unacceptable.
2033
2034Tests
2035
2036- Fixed the pickle tests to work with "import test.test_pickle".
2037
2038- Tweaked test_locale.py to actually run the test Windows.
2039
2040- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
2041 not "wb" (which is not a valid mode at all).
2042
2043- Fix pstats browser crashes. Import readline if it exists to make
2044 the user interface nicer.
2045
2046- Add "import thread" to the top of test modules that import the
2047 threading module (test_asynchat and test_threadedtempfile). This
2048 prevents test failures caused by a broken threading module resulting
2049 from a previously caught failed import.
2050
2051- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
2052 needed on some platforms (e.g. Solaris 8) when the tests are run
2053 twice in succession.
2054
2055- Skip rather than fail test_sunaudiodev if no audio device is found.
2056
2057
2058What's New in Python 2.1c1?
2059===========================
2060
2061This list was significantly updated when 2.1c2 was released; the 2.1c1
2062release didn't mention most changes that were actually part of 2.1c1:
2063
2064Legal
2065
2066- Copyright was assigned to the Python Software Foundation (PSF) and a
2067 PSF license (very similar to the CNRI license) was added.
2068
2069- The CNRI copyright notice was updated to include 2001.
2070
2071Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00002072
Guido van Rossumc9932722001-04-12 02:31:27 +00002073- After a public outcry, assignment to __debug__ is no longer illegal;
2074 instead, a warning is issued. It will become illegal in 2.2.
2075
Guido van Rossum5b08f132001-04-16 02:05:23 +00002076- Fixed a core dump with "%#x" % 0, and changed the semantics so that
2077 "%#x" now always prepends "0x", even if the value is zero.
2078
2079- Fixed some nits in the bytecode compiler.
2080
2081- Fixed core dumps when calling certain kinds of non-functions.
2082
2083- Fixed various core dumps caused by reference count bugs.
2084
2085Build and Ports
2086
2087- Use INSTALL_SCRIPT to install script files.
2088
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002089- New port: SCO Unixware 7, by Billy G. Allie.
2090
Guido van Rossum5b08f132001-04-16 02:05:23 +00002091- Updated RISCOS port.
2092
2093- Updated BeOS port and notes.
2094
2095- Various other porting problems resolved.
2096
2097Library
2098
2099- The TERMIOS and SOCKET modules are now truly obsolete and
2100 unnecessary. Their symbols are incorporated in the termios and
2101 socket modules.
2102
2103- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
2104 better tests for pickling.
2105
2106- threading: make Condition.wait() robust against KeyboardInterrupt.
2107
2108- zipfile: add support to zipfile to support opening an archive
2109 represented by an open file rather than a file name. Fix bug where
2110 the archive was not properly closed. Fixed a bug in this bugfix
2111 where flush() was called for a read-only file.
2112
2113- imputil: added an uninstall() method to the ImportManager.
2114
2115- Canvas: fixed bugs in lower() and tkraise() methods.
2116
2117- SocketServer: API change (added overridable close_request() method)
2118 so that the TCP server can explicitly close the request.
2119
2120- pstats: Eric Raymond added a simple interactive statistics browser,
2121 invoked when the module is run as a script.
2122
2123- locale: fixed a problem in format().
2124
2125- webbrowser: made it work when the BROWSER environment variable has a
2126 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
2127 KDE 2. Fixed some other nits.
2128
2129- unittest: changes to allow using a different exception than
2130 AssertionError, and added a few more function aliases. Some other
2131 small changes.
2132
2133- urllib, urllib2: fixed redirect problems and a coupleof other nits.
2134
2135- asynchat: fixed a critical bug in asynchat that slipped through the
2136 2.1b2 release. Fixed another rare bug.
2137
2138- Fix some unqualified except: clauses (always a bad code example).
2139
2140XML
2141
2142- pyexpat: new API get_version_string().
2143
2144- Fixed some minidom bugs.
2145
2146Extensions
2147
2148- Fixed a core dump in _weakref. Removed the weakref.mapping()
2149 function (it adds nothing to the API).
2150
2151- Rationalized the use of header files in the readline module, to make
2152 it compile (albeit with some warnings) with the very recent readline
2153 4.2, without breaking for earlier versions.
2154
2155- Hopefully fixed a buffering problem in linuxaudiodev.
2156
2157- Attempted a fix to make the OpenSSL support in the socket module
2158 work again with pre-0.9.5 versions of OpenSSL.
2159
2160Tests
2161
2162- Added a test case for asynchat and asyncore.
2163
2164- Removed coupling between tests where one test failing could break
2165 another.
2166
2167Tools
2168
2169- Ping added an interactive help browser to pydoc, fixed some nits
2170 in the rest of the pydoc code, and added some features to his
2171 inspect module.
2172
2173- An updated python-mode.el version 4.1 which integrates Ken
2174 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
2175 much nicer in XEmacs and Emacs. When stepping through your program
2176 with pdb, in either the shell window or the *Python* window, the
2177 source file and line will be tracked by an arrow. Very cool!
2178
2179- IDLE: syntax warnings in interactive mode are changed into errors.
2180
2181- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00002182 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00002183
2184- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002185
Barry Warsaw11e89c72001-04-11 20:37:57 +00002186
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002187What's New in Python 2.1 beta 2?
2188================================
2189
Guido van Rossum053ae352001-03-22 14:17:21 +00002190(Unlisted are many fixed bugs, more documentation, etc.)
2191
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002192Core language, builtins, and interpreter
2193
Guido van Rossum053ae352001-03-22 14:17:21 +00002194- The nested scopes work (enabled by "from __future__ import
2195 nested_scopes") is completed; in particular, the future now extends
2196 into code executed through exec, eval() and execfile(), and into the
2197 interactive interpreter.
2198
2199- When calling a base class method (e.g. BaseClass.__init__(self)),
2200 this is now allowed even if self is not strictly spoken a class
2201 instance (e.g. when using metaclasses or the Don Beaudry hook).
2202
2203- Slice objects are now comparable but not hashable; this prevents
2204 dict[:] from being accepted but meaningless.
2205
2206- Complex division is now calculated using less braindead algorithms.
2207 This doesn't change semantics except it's more likely to give useful
2208 results in extreme cases. Complex repr() now uses full precision
2209 like float repr().
2210
2211- sgmllib.py now calls handle_decl() for simple <!...> declarations.
2212
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002213- It is illegal to assign to the name __debug__, which is set when the
2214 interpreter starts. It is effectively a compile-time constant.
2215
2216- A warning will be issued if a global statement for a variable
2217 follows a use or assignment of that variable.
2218
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002219Standard library
2220
Guido van Rossum053ae352001-03-22 14:17:21 +00002221- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
2222 inspired by JUnit), is now part of the standard library. You now
2223 have a choice of two testing frameworks: unittest requires you to
2224 write testcases as separate code, doctest gathers them from
2225 docstrings. Both approaches have their advantages and
2226 disadvantages.
2227
2228- A new module Tix was added, which wraps the Tix extension library
2229 for Tk. With that module, it is not necessary to statically link
2230 Tix with _tkinter, since Tix will be loaded with Tcl's "package
2231 require" command. See Demo/tix/.
2232
2233- tzparse.py is now obsolete.
2234
2235- In gzip.py, the seek() and tell() methods are removed -- they were
2236 non-functional anyway, and it's better if callers can test for their
2237 existence with hasattr().
2238
2239Python/C API
2240
2241- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
2242 that's already in the dictionary during a PyDict_Next() iteration.
2243 This used to fail occasionally when a dictionary resize operation
2244 could be triggered that would rehash all the keys. All other
2245 modifications to the dictionary are still off-limits during a
2246 PyDict_Next() iteration!
2247
2248- New extended APIs related to passing compiler variables around.
2249
2250- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
2251 implement isinstance() and issubclass().
2252
2253- Py_BuildValue() now has a "D" conversion to create a Python complex
2254 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002255
Fred Drake4e262a92001-03-22 18:26:47 +00002256- Extensions types which support weak references must now set the
2257 field allocated for the weak reference machinery to NULL themselves;
2258 this is done to avoid the cost of checking each object for having a
2259 weakly referencable type in PyObject_INIT(), since most types are
2260 not weakly referencable.
2261
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002262- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
2263 free variables and cell variables to and from the frame's f_locals.
2264
2265- Variants of several functions defined in pythonrun.h have been added
2266 to support the nested_scopes future statement. The variants all end
2267 in Flags and take an extra argument, a PyCompilerFlags *; examples:
2268 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
2269 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00002270 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002271
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002272Distutils
2273
2274- the sdist command now writes a PKG-INFO file, as described in PEP 241,
2275 into the release tree.
2276
Tim Peters0e57abf2001-05-02 07:39:38 +00002277- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002278 (an uninstaller, more customization of the installer's display)
2279
2280- from Jack Jansen: added Mac-specific code to generate a dialog for
2281 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00002282 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002283 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00002284
2285- added 'platforms' and 'keywords' to the set of metadata that can be
2286 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002287
2288- applied patches from Jason Tishler to make the compiler class work with
2289 Cygwin.
2290
2291
Tim Peters2fe289a2001-03-01 22:19:38 +00002292What's New in Python 2.1 beta 1?
2293================================
Tim Petersd66595f2001-02-04 03:09:53 +00002294
2295Core language, builtins, and interpreter
2296
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00002297- Following an outcry from the community about the amount of code
2298 broken by the nested scopes feature introduced in 2.1a2, we decided
2299 to make this feature optional, and to wait until Python 2.2 (or at
2300 least 6 months) to make it standard. The option can be enabled on a
2301 per-module basis by adding "from __future__ import nested_scopes" at
2302 the beginning of a module (before any other statements, but after
2303 comments and an optional docstring). See PEP 236 (Back to the
2304 __future__) for a description of the __future__ statement. PEP 227
2305 (Statically Nested Scopes) has been updated to reflect this change,
2306 and to clarify the semantics in a number of endcases.
2307
2308- The nested scopes code, when enabled, has been hardened, and most
2309 bugs and memory leaks in it have been fixed.
2310
2311- Compile-time warnings are now generated for a number of conditions
2312 that will break or change in meaning when nested scopes are enabled:
2313
2314 - Using "from...import *" or "exec" without in-clause in a function
2315 scope that also defines a lambda or nested function with one or
2316 more free (non-local) variables. The presence of the import* or
2317 bare exec makes it impossible for the compiler to determine the
2318 exact set of local variables in the outer scope, which makes it
2319 impossible to determine the bindings for free variables in the
2320 inner scope. To avoid the warning about import *, change it into
2321 an import of explicitly name object, or move the import* statement
2322 to the global scope; to avoid the warning about bare exec, use
2323 exec...in... (a good idea anyway -- there's a possibility that
2324 bare exec will be deprecated in the future).
2325
2326 - Use of a global variable in a nested scope with the same name as a
2327 local variable in a surrounding scope. This will change in
2328 meaning with nested scopes: the name in the inner scope will
2329 reference the variable in the outer scope rather than the global
2330 of the same name. To avoid the warning, either rename the outer
2331 variable, or use a global statement in the inner function.
2332
Neil Schemenauera35c6882001-02-27 04:45:05 +00002333- An optional object allocator has been included. This allocator is
2334 optimized for Python objects and should be faster and use less memory
2335 than the standard system allocator. It is not enabled by default
2336 because of possible thread safety problems. The allocator is only
2337 protected by the Python interpreter lock and it is possible that some
2338 extension modules require a thread safe allocator. The object
2339 allocator can be enabled by providing the "--with-pymalloc" option to
2340 configure.
2341
Tim Petersd66595f2001-02-04 03:09:53 +00002342Standard library
2343
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002344- pyexpat now detects the expat version if expat.h defines it. A
2345 number of additional handlers are provided, which are only available
2346 since expat 1.95. In addition, the methods SetParamEntityParsing and
2347 GetInputContext of Parser objects are available with 1.95.x
2348 only. Parser objects now provide the ordered_attributes and
2349 specified_attributes attributes. A new module expat.model was added,
2350 which offers a number of additional constants if 1.95.x is used.
2351
2352- xml.dom offers the new functions registerDOMImplementation and
2353 getDOMImplementation.
2354
2355- xml.dom.minidom offers a toprettyxml method. A number of DOM
2356 conformance issues have been resolved. In particular, Element now
2357 has an hasAttributes method, and the handling of namespaces was
2358 improved.
2359
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002360- Ka-Ping Yee contributed two new modules: inspect.py, a module for
2361 getting information about live Python code, and pydoc.py, a module
2362 for interactively converting docstrings to HTML or text.
2363 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002364 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002365 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2366 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002367
Tim Peters1eff7962001-03-01 02:31:33 +00002368- New library module difflib.py, primarily packaging the SequenceMatcher
2369 class at the heart of the popular ndiff.py file-comparison tool.
2370
2371- doctest.py (a framework for verifying Python code examples in docstrings)
2372 is now part of the std library.
2373
Tim Petersd66595f2001-02-04 03:09:53 +00002374Windows changes
2375
Guido van Rossume3955a82001-03-02 14:05:59 +00002376- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2377 small GUI that lets you browse the module docstrings using your
2378 default web browser.
2379
Tim Peters1eff7962001-03-01 02:31:33 +00002380- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2381 Platforms) is implemented. See
2382
2383 http://python.sourceforge.net/peps/pep-0235.html
2384
2385 for full details, especially the "Current Lower-Left Semantics" section.
2386 The new Windows import rules are simpler than before:
2387
2388 A. If the PYTHONCASEOK environment variable exists, same as
2389 before: silently accept the first case-insensitive match of any
2390 kind; raise ImportError if none found.
2391
2392 B. Else search sys.path for the first case-sensitive match; raise
2393 ImportError if none found.
2394
2395 The same rules have been implented on other platforms with case-
2396 insensitive but case-preserving filesystems too (including Cygwin, and
2397 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002398
Tim Peters25a9ce32001-02-19 07:06:36 +00002399- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2400 what it's supposed to do (and does do under NT and 2000) via direct
2401 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002402 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002403 all Win9x systems before.
2404
Tim Peters1eff7962001-03-01 02:31:33 +00002405- Build: Subproject _test (effectively) renamed to _testcapi.
2406
Tim Peters2fe289a2001-03-01 22:19:38 +00002407New platforms
2408
2409- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2410 Thanks to Steven Majewski!
2411
2412- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2413 Tishler!
2414
Guido van Rossum9089b272001-03-02 06:49:50 +00002415- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2416 Schwertberger! See RISCOS/README for more information -- it seems
2417 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002418 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002419
Tim Peters25a9ce32001-02-19 07:06:36 +00002420
Tim Petersd7b5e882001-01-25 03:36:26 +00002421What's New in Python 2.1 alpha 2?
2422=================================
Tim Peters40ead762001-01-27 05:35:26 +00002423
Tim Petersd7b5e882001-01-25 03:36:26 +00002424Core language, builtins, and interpreter
2425
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002426- Scopes nest. If a name is used in a function or class, but is not
2427 local, the definition in the nearest enclosing function scope will
2428 be used. One consequence of this change is that lambda statements
2429 could reference variables in the namespaces where the lambda is
2430 defined. In some unusual cases, this change will break code.
2431
2432 In all previous version of Python, names were resolved in exactly
2433 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002434 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002435 function A is defined within a function B, the names bound in B are
2436 not visible in A. The new rules make names bound in B visible in A,
2437 unless A contains a name binding that hides the binding in B.
2438
2439 Section 4.1 of the reference manual describes the new scoping rules
2440 in detail. The test script in Lib/test/test_scope.py demonstrates
2441 some of the effects of the change.
2442
2443 The new rules will cause existing code to break if it defines nested
2444 functions where an outer function has local variables with the same
2445 name as globals or builtins used by the inner function. Example:
2446
2447 def munge(str):
2448 def helper(x):
2449 return str(x)
2450 if type(str) != type(''):
2451 str = helper(str)
2452 return str.strip()
2453
2454 Under the old rules, the name str in helper() is bound to the
2455 builtin function str(). Under the new rules, it will be bound to
2456 the argument named str and an error will occur when helper() is
2457 called.
2458
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002459- The compiler will report a SyntaxError if "from ... import *" occurs
2460 in a function or class scope. The language reference has documented
2461 that this case is illegal, but the compiler never checked for it.
2462 The recent introduction of nested scope makes the meaning of this
2463 form of name binding ambiguous. In a future release, the compiler
2464 may allow this form when there is no possibility of ambiguity.
2465
Tim Peters40ead762001-01-27 05:35:26 +00002466- repr(string) is easier to read, now using hex escapes instead of octal,
2467 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2468
2469 >>> "\texample \r\n" + chr(0) + chr(255)
2470 '\texample \r\n\x00\xff' # in 2.1
2471 '\011example \015\012\000\377' # in 2.0
2472
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002473- Functions are now compared and hashed by identity, not by value, since
2474 the func_code attribute is writable.
2475
Fred Drakefb9d7122001-02-01 20:00:40 +00002476- Weak references (PEP 205) have been added. This involves a few
2477 changes in the core, an extension module (_weakref), and a Python
2478 module (weakref). The weakref module is the public interface. It
2479 includes support for "explicit" weak references, proxy objects, and
2480 mappings with weakly held values.
2481
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002482- A 'continue' statement can now appear in a try block within the body
2483 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002484 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002485
Tim Petersd7b5e882001-01-25 03:36:26 +00002486Standard library
2487
Barry Warsaw30dbd142001-01-31 22:14:01 +00002488- mailbox.py now has a new class, PortableUnixMailbox which is
2489 identical to UnixMailbox but uses a more portable scheme for
2490 determining From_ separators. Also, the constructors for all the
2491 classes in this module have a new optional `factory' argument, which
2492 is a callable used when new message classes must be instantiated by
2493 the next() method.
2494
Tim Petersd7b5e882001-01-25 03:36:26 +00002495- random.py is now self-contained, and offers all the functionality of
2496 the now-deprecated whrandom.py. See the docs for details. random.py
2497 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002498 and restoring the internal state of the generator; and jumpahead(n),
2499 for quickly forcing the internal state to be the same as if n calls to
2500 random() had been made. The latter is particularly useful for multi-
2501 threaded programs, creating one instance of the random.Random() class for
2502 each thread, then using .jumpahead() to force each instance to use a
2503 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002504
Tim Peters0de88fc2001-02-01 04:59:18 +00002505- random.py's seed() function is new. For bit-for-bit compatibility with
2506 prior releases, use the whseed function instead. The new seed function
2507 addresses two problems: (1) The old function couldn't produce more than
2508 about 2**24 distinct internal states; the new one about 2**45 (the best
2509 that can be done in the Wichmann-Hill generator). (2) The old function
2510 sometimes produced identical internal states when passed distinct
2511 integers, and there was no simple way to predict when that would happen;
2512 the new one guarantees to produce distinct internal states for all
2513 arguments in [0, 27814431486576L).
2514
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002515- The socket module now supports raw packets on Linux. The socket
2516 family is AF_PACKET.
2517
Tim Peters9ea17ac2001-02-02 05:57:15 +00002518- test_capi.py is a start at running tests of the Python C API. The tests
2519 are implemented by the new Modules/_testmodule.c.
2520
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002521- A new extension module, _symtable, provides provisional access to the
2522 internal symbol table used by the Python compiler. A higher-level
2523 interface will be added on top of _symtable in a future release.
2524
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002525- Removed the obsolete soundex module.
2526
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002527- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2528 the isSameNode method; NamedNodeMap the get method.
2529
2530- xml.sax.expatreader supports the lexical handler property; it
2531 generates comment, startCDATA, and endCDATA events.
2532
Tim Petersee826f82001-01-31 19:39:44 +00002533Windows changes
2534
2535- Build procedure: the zlib project is built in a different way that
2536 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002537 the zlib binary used. See PCbuild\readme.txt for details. Your old
2538 zlib-related directories can be deleted; you'll need to download fresh
2539 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002540
Tim Peters9ea17ac2001-02-02 05:57:15 +00002541- Build: New subproject _test for the benefit of test_capi.py (see above).
2542
Tim Petersb16c56f2001-02-02 21:24:51 +00002543- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2544 interface to some Python compiler internals).
2545
2546- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002547 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002548
Tim Petersa3a3a032000-11-30 05:22:44 +00002549What's New in Python 2.1 alpha 1?
2550=================================
2551
2552Core language, builtins, and interpreter
2553
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002554- There is a new Unicode companion to the PyObject_Str() API
2555 called PyObject_Unicode(). It behaves in the same way as the
2556 former, but assures that the returned value is an Unicode object
2557 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002558
Guido van Rossumf98eda02001-01-17 15:54:45 +00002559- The comparison operators support "rich comparison overloading" (PEP
2560 207). C extension types can provide a rich comparison function in
2561 the new tp_richcompare slot in the type object. The cmp() function
2562 and the C function PyObject_Compare() first try the new rich
2563 comparison operators before trying the old 3-way comparison. There
2564 is also a new C API PyObject_RichCompare() (which also falls back on
2565 the old 3-way comparison, but does not constrain the outcome of the
2566 rich comparison to a Boolean result).
2567
2568 The rich comparison function takes two objects (at least one of
2569 which is guaranteed to have the type that provided the function) and
2570 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2571 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2572 object, which may be NotImplemented (in which case the tp_compare
2573 slot function is used as a fallback, if defined).
2574
2575 Classes can overload individual comparison operators by defining one
2576 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002577 __ge__. There are no explicit "reflected argument" versions of
2578 these; instead, __lt__ and __gt__ are each other's reflection,
2579 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2580 reflection (similar at the C level). No other implications are
2581 made; in particular, Python does not assume that == is the Boolean
2582 inverse of !=, or that < is the Boolean inverse of >=. This makes
2583 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002584
2585 Classes or types that want to implement (in)equality tests but not
2586 the ordering operators (i.e. unordered types) should implement ==
2587 and !=, and raise an error for the ordering operators.
2588
Guido van Rossuma88479f2001-01-18 14:28:08 +00002589 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002590 Boolean; e.g. a matrix type might want to return a matrix of bits
2591 for A < B, giving elementwise comparisons. Such types should ensure
2592 that any interpretation of their value in a Boolean context raises
2593 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2594 at the C level) to always raise an exception.
2595
Guido van Rossuma88479f2001-01-18 14:28:08 +00002596- Complex numbers use rich comparisons to define == and != but raise
2597 an exception for <, <=, > and >=. Unfortunately, this also means
2598 that cmp() of two complex numbers raises an exception when the two
2599 numbers differ. Since it is not mathematically meaningful to compare
2600 complex numbers except for equality, I hope that this doesn't break
2601 too much code.
2602
Tim Peters3389f192001-02-18 08:48:49 +00002603- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002604 not defined by the language, other than that it's arbitrary but
2605 consistent (see the Reference Manual). An implementation detail changed
2606 in 2.1a1 such that None now compares less than any other object. Code
2607 relying on this new behavior (like code that relied on the previous
2608 behavior) does so at its own risk.
2609
Barry Warsaw573b5412001-01-15 20:43:18 +00002610- Functions and methods now support getting and setting arbitrarily
2611 named attributes (PEP 232). Functions have a new __dict__
2612 (a.k.a. func_dict) which hold the function attributes. Methods get
2613 and set attributes on their underlying im_func. It is a TypeError
2614 to set an attribute on a bound method.
2615
Guido van Rossum051e3352001-01-15 19:11:10 +00002616- The xrange() object implementation has been improved so that
2617 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2618 limitation that in this case len(xrange(sys.maxint)) can't be
2619 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2620 work fine as long as the index i doesn't actually reach 2**31.
2621 (Python uses regular ints for sequence and string indices; fixing
2622 that is much more work.)
2623
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002624- Two changes to from...import:
2625
Guido van Rossumba381232001-02-03 15:06:40 +00002626 1) "from M import X" now works even if (after loading module M)
2627 sys.modules['M'] is not a real module; it's basically a getattr()
2628 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002629
2630 2) "from M import *" now looks for M.__all__ to decide which names to
2631 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2632 filters out names starting with '_' as before. Whether or not
2633 __all__ exists, there's no restriction on the type of M.
2634
Guido van Rossumf61f1662001-01-10 20:13:55 +00002635- File objects have a new method, xreadlines(). This is the fastest
2636 way to iterate over all lines in a file:
2637
2638 for line in file.xreadlines():
2639 ...do something to line...
2640
2641 See the xreadlines module (mentioned below) for how to do this for
2642 other file-like objects.
2643
2644- Even if you don't use file.xreadlines(), you may expect a speedup on
2645 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002646 quite a bit in platform-specific ways: on systems (like Linux) that
2647 support flockfile(), getc_unlocked(), and funlockfile(), those are
2648 used by default. On systems (like Windows) without getc_unlocked(),
2649 a complicated (but still thread-safe) method using fgets() is used by
2650 default.
2651
Tim Petersd52269b2001-01-25 06:23:18 +00002652 You can force use of the fgets() method by #define'ing
2653 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002654 getc_unlocked()).
2655
Tim Petersd52269b2001-01-25 06:23:18 +00002656 You can force fgets() not to be used by #define'ing
2657 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002658 test_bufio.py fails -- and let us know if it does!).
2659
2660- In addition, the fileinput module, while still slower than the other
2661 methods on most platforms, has been sped up too, by using
2662 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002663
2664- Support for run-time warnings has been added, including a new
2665 command line option (-W) to specify the disposition of warnings.
2666 See the description of the warnings module below.
2667
2668- Extensive changes have been made to the coercion code. This mostly
2669 affects extension modules (which can now implement mixed-type
2670 numerical operators without having to use coercion), but
2671 occasionally, in boundary cases the coercion semantics have changed
2672 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002673 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002674 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002675 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002676
Guido van Rossumf98eda02001-01-17 15:54:45 +00002677- In connection with the coercion changes, a new built-in singleton
2678 object, NotImplemented is defined. This can be returned for
2679 operations that wish to indicate they are not implemented for a
2680 particular combination of arguments. From C, this is
2681 Py_NotImplemented.
2682
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002683- The interpreter accepts now bytecode files on the command line even
2684 if they do not have a .pyc or .pyo extension. On Linux, after executing
2685
Martin v. Löwise214baa2001-02-04 22:37:56 +00002686import imp,sys,string
2687magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2688reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2689open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002690
2691 any byte code file can be used as an executable (i.e. as an argument
2692 to execve(2)).
2693
Tim Peters9940b802000-12-01 07:59:35 +00002694- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002695 character. In 1.6 and earlier, they never produced a sign,
2696 and raised an error if the value of the long was too large
2697 to fit in a Python int. In 2.0, they produced a sign if and
2698 only if too large to fit in an int. This was inconsistent
2699 across platforms (because the size of an int varies across
2700 platforms), and inconsistent with hex() and oct(). Example:
2701
2702 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002703 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002704 'ffffffbe' # in 2.0 and before, on 32-bit machines
2705 >>> hex(-0x42L)
2706 '-0x42L' # in all versions of Python
2707
Tim Peters9940b802000-12-01 07:59:35 +00002708 The behavior of %d formats for negative Python longs remains
2709 the same as in 2.0 (although in 1.6 and before, they raised
2710 an error if the long didn't fit in a Python int).
2711
2712 %u formats don't make sense for Python longs, but are allowed
2713 and treated the same as %d in 2.1. In 2.0, a negative long
2714 formatted via %u produced a sign if and only if too large to
2715 fit in an int. In 1.6 and earlier, a negative long formatted
2716 via %u raised an error if it was too big to fit in an int.
2717
Guido van Rossum3661d392000-12-12 22:10:31 +00002718- Dictionary objects have an odd new method, popitem(). This removes
2719 an arbitrary item from the dictionary and returns it (in the form of
2720 a (key, value) pair). This can be useful for algorithms that use a
2721 dictionary as a bag of "to do" items and repeatedly need to pick one
2722 item. Such algorithms normally end up running in quadratic time;
2723 using popitem() they can usually be made to run in linear time.
2724
Tim Peters36cdad12000-12-29 02:06:45 +00002725Standard library
2726
Thomas Woutersfe385252001-01-19 23:16:56 +00002727- In the time module, the time argument to the functions strftime,
2728 localtime, gmtime, asctime and ctime is now optional, defaulting to
2729 the current time (in the local timezone).
2730
Guido van Rossumda91f222001-01-15 16:36:08 +00002731- The ftplib module now defaults to passive mode, which is deemed a
2732 more useful default given that clients are often inside firewalls
2733 these days. Note that this could break if ftplib is used to connect
2734 to a *server* that is inside a firewall, from outside; this is
2735 expected to be a very rare situation. To fix that, you can call
2736 ftp.set_pasv(0).
2737
Martin v. Löwis10a27872001-01-13 09:54:41 +00002738- The module site now treats .pth files not only for path configuration,
2739 but also supports extensions to the initialization code: Lines starting
2740 with import are executed.
2741
Guido van Rossumf61f1662001-01-10 20:13:55 +00002742- There's a new module, warnings, which implements a mechanism for
2743 issuing and filtering warnings. There are some new built-in
2744 exceptions that serve as warning categories, and a new command line
2745 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2746 turns warnings into errors). warnings.warn(message[, category])
2747 issues a warning message; this can also be called from C as
2748 PyErr_Warn(category, message).
2749
2750- A new module xreadlines was added. This exports a single factory
2751 function, xreadlines(). The intention is that this code is the
2752 absolutely fastest way to iterate over all lines in an open
2753 file(-like) object:
2754
2755 import xreadlines
2756 for line in xreadlines.xreadlines(file):
2757 ...do something to line...
2758
2759 This is equivalent to the previous the speed record holder using
2760 file.readlines(sizehint). Note that if file is a real file object
2761 (as opposed to a file-like object), this is equivalent:
2762
2763 for line in file.xreadlines():
2764 ...do something to line...
2765
Tim Peters36cdad12000-12-29 02:06:45 +00002766- The bisect module has new functions bisect_left, insort_left,
2767 bisect_right and insort_right. The old names bisect and insort
2768 are now aliases for bisect_right and insort_right. XXX_right
2769 and XXX_left methods differ in what happens when the new element
2770 compares equal to one or more elements already in the list: the
2771 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002772 right. Code that doesn't care where equal elements end up should
2773 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002774
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002775- The new curses.panel module wraps the panel library that forms part
2776 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2777
Guido van Rossumf61f1662001-01-10 20:13:55 +00002778- The SocketServer module now sets the allow_reuse_address flag by
2779 default in the TCPServer class.
2780
2781- A new function, sys._getframe(), returns the stack frame pointer of
2782 the caller. This is intended only as a building block for
2783 higher-level mechanisms such as string interpolation.
2784
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002785- The pyexpat module supports a number of new handlers, which are
2786 available only in expat 1.2. If invocation of a callback fails, it
2787 will report an additional frame in the traceback. Parser objects
2788 participate now in garbage collection. If expat reports an unknown
2789 encoding, pyexpat will try to use a Python codec; that works only
2790 for single-byte charsets. The parser type objects is exposed as
2791 XMLParserObject.
2792
2793- xml.dom now offers standard definitions for symbolic node type and
2794 exception code constants, and a hierarchy of DOM exceptions. minidom
2795 was adjusted to use them.
2796
2797- The conformance of xml.dom.minidom to the DOM specification was
2798 improved. It detects a number of additional error cases; the
2799 previous/next relationship works even when the tree is modified;
2800 Node supports the normalize() method; NamedNodeMap, DocumentType and
2801 DOMImplementation classes were added; Element supports the
2802 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2803 method.
2804
Guido van Rossumf61f1662001-01-10 20:13:55 +00002805Build issues
2806
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002807- For Unix (and Unix-compatible) builds, configuration and building of
2808 extension modules is now greatly automated. Rather than having to
2809 edit the Modules/Setup file to indicate which modules should be
2810 built and where their include files and libraries are, a
2811 distutils-based setup.py script now takes care of building most
2812 extension modules. All extension modules built this way are built
2813 as shared libraries. Only a few modules that must be linked
2814 statically are still listed in the Setup file; you won't need to
2815 edit their configuration.
2816
2817- Python should now build out of the box on Cygwin. If it doesn't,
2818 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002819
2820- Python now always uses its own (renamed) implementation of getopt()
2821 -- there's too much variation among C library getopt()
2822 implementations.
2823
2824- C++ compilers are better supported; the CXX macro is always set to a
2825 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002826
Tim Petersd92dfe02000-12-12 01:18:41 +00002827Windows changes
2828
2829- select module: By default under Windows, a select() call
2830 can specify no more than 64 sockets. Python now boosts
2831 this Microsoft default to 512. If you need even more than
2832 that, see the MS docs (you'll need to #define FD_SETSIZE
2833 and recompile Python from source).
2834
Guido van Rossumf61f1662001-01-10 20:13:55 +00002835- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2836 subdirectory is no more!
2837
Tim Petersa3a3a032000-11-30 05:22:44 +00002838
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002839What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002840=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002841
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002842Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002843changes are in the file HISTORY. If you are making the jump directly
2844from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2845HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002846
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002847Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2848the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2849http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002850
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002851--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002852
2853======================================================================
2854
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002855What's new in 2.0 (since release candidate 1)?
2856==============================================
2857
2858Standard library
2859
2860- The copy_reg module was modified to clarify its intended use: to
2861 register pickle support for extension types, not for classes.
2862 pickle() will raise a TypeError if it is passed a class.
2863
2864- Fixed a bug in gettext's "normalize and expand" code that prevented
2865 it from finding an existing .mo file.
2866
2867- Restored support for HTTP/0.9 servers in httplib.
2868
Tim Peters989b7b92000-10-16 20:24:53 +00002869- The math module was changed to stop raising OverflowError in case of
2870 underflow, and return 0 instead in underflow cases. Whether Python
2871 used to raise OverflowError in case of underflow was platform-
2872 dependent (it did when the platform math library set errno to ERANGE
2873 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002874
2875- Fixed a bug in StringIO that occurred when the file position was not
2876 at the end of the file and write() was called with enough data to
2877 extend past the end of the file.
2878
2879- Fixed a bug that caused Tkinter error messages to get lost on
2880 Windows. The bug was fixed by replacing direct use of
2881 interp->result with Tcl_GetStringResult(interp).
2882
2883- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2884 redirect response.
2885
2886- Several changes were made to distutils: Some debugging code was
2887 removed from util. Fixed the installer used when an external zip
2888 program (like WinZip) is not found; the source code for this
2889 installer is in Misc/distutils. check_lib() was modified to behave
2890 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2891 test for whether installed modules are on sys.path was changed to
2892 use both normcase() and normpath().
2893
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002894- Several minor bugs were fixed in the xml package (the minidom,
2895 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002896
2897- The regression test driver (regrtest.py) behavior when invoked with
2898 -l changed: It now reports a count of objects that are recognized as
2899 garbage but not freed by the garbage collector.
2900
Tim Peters989b7b92000-10-16 20:24:53 +00002901- The regression test for the math module was changed to test
2902 exceptional behavior when the test is run in verbose mode. Python
2903 cannot yet guarantee consistent exception behavior across platforms,
2904 so the exception part of test_math is run only in verbose mode, and
2905 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002906
2907Internals
2908
2909- PyOS_CheckStack() has been disabled on Win64, where it caused
2910 test_sre to fail.
2911
2912Build issues
2913
2914- Changed compiler flags, so that gcc is always invoked with -Wall and
2915 -Wstrict-prototypes. Users compiling Python with GCC should see
2916 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002917 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002918 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002919
Tim Petersa3a3a032000-11-30 05:22:44 +00002920- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002921
2922Tools and other miscellany
2923
2924- The compiler in Tools/compiler was updated to support the new
2925 language features introduced in 2.0: extended print statement, list
2926 comprehensions, and augmented assignments. The new compiler should
2927 also be backwards compatible with Python 1.5.2; the compiler will
2928 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002929 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002930
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002931What's new in 2.0 release candidate 1 (since beta 2)?
2932=====================================================
2933
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002934What is release candidate 1?
2935
2936We believe that release candidate 1 will fix all known bugs that we
2937intend to fix for the 2.0 final release. This release should be a bit
2938more stable than the previous betas. We would like to see even more
2939widespread testing before the final release, so we are producing this
2940release candidate. The final release will be exactly the same unless
2941any show-stopping (or brown bag) bugs are found by testers of the
2942release candidate.
2943
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002944All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002945to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002946
2947Core language, builtins, and interpreter
2948
2949- A bug that caused crashes when __coerce__ was used with augmented
2950 assignment, e.g. +=, was fixed.
2951
2952- Raise ZeroDivisionError when raising zero to a negative number,
2953 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2954 power operator and the result of math.pow(0.0, -2.0) will vary by
2955 platform. On Linux, it raises a ValueError.
2956
2957- A bug in Unicode string interpolation was fixed that occasionally
2958 caused errors with formats including "%%". For example, the
2959 following expression "%% %s" % u"abc" no longer raises a TypeError.
2960
2961- Compilation of deeply nested expressions raises MemoryError instead
2962 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2963
2964- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2965 rendering them useless. They are now written in binary mode again.
2966
2967Standard library
2968
2969- Keyword arguments are now accepted for most pattern and match object
2970 methods in SRE, the standard regular expression engine.
2971
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002972- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002973 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002974
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002975- Several bugs in the Unicode handling and error handling in _tkinter
2976 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002977
2978- Fix memory management errors in Merge() and Tkapp_Call() routines.
2979
2980- Several changes were made to cStringIO to make it compatible with
2981 the file-like object interface and with StringIO. If operations are
2982 performed on a closed object, an exception is raised. The truncate
2983 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002984 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002985
2986- There were many changes made to the linuxaudiodev module and its
2987 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002988 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002989
2990 Note that this module is named poorly, because it should work
2991 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002992 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002993
2994 The module now raises exceptions when errors occur instead of
2995 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2996 audio) and defines a getptr() method that calls the
2997 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2998
2999- The library_version attribute, introduced in an earlier beta, was
3000 removed because it can not be supported with early versions of the C
3001 readline library, which provides no way to determine the version at
3002 compile-time.
3003
3004- The binascii module is now enabled on Win64.
3005
Tim Peters46446d62000-10-09 21:19:31 +00003006- tokenize.py no longer suffers "recursion depth" errors when parsing
3007 programs with very long string literals.
3008
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003009Internals
3010
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003011- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003012 which is called when the interpreter starts up to determine where
3013 the standard library is installed. These vulnerabilities affect all
3014 previous versions of Python and can be exploited by setting very
3015 long values for PYTHONHOME or argv[0]. The risk is greatest for a
3016 setuid Python script, although use of the wrapper in
3017 Misc/setuid-prog.c will eliminate the vulnerability.
3018
3019- Fixed garbage collection bugs in instance creation that were
3020 triggered when errors occurred during initialization. The solution,
3021 applied in cPickle and in PyInstance_New(), is to call
3022 PyObject_GC_Init() after the initialization of the object's
3023 container attributes is complete.
3024
3025- pyexpat adds definitions of PyModule_AddStringConstant and
3026 PyModule_AddObject if the Python version is less than 2.0, which
3027 provides compatibility with PyXML on Python 1.5.2.
3028
3029- If the platform has a bogus definition for LONG_BIT (the number of
3030 bits in a long), an error will be reported at compile time.
3031
3032- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
3033 collection crashes and possibly other, unreported crashes.
3034
3035- Fixed a memory leak in _PyUnicode_Fini().
3036
3037Build issues
3038
3039- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003040 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00003041 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003042
3043- The mmap.PAGESIZE constant is now initialized using sysconf when
3044 possible, which eliminates a dependency on -lucb for Reliant UNIX.
3045
3046- The md5 file should now compile on all platforms.
3047
3048- The select module now compiles on platforms that do not define
3049 POLLRDNORM and related constants.
3050
3051- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00003052 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003053
Jeremy Hylton10921202000-10-09 18:34:12 +00003054- BeOS: A number of changes were made to the build and installation
3055 process. ar-fake now operates on a directory of object files.
3056 dl_export.h is gone, and its macros now appear on the mwcc command
3057 line during build on PPC BeOS.
3058
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003059- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00003060 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003061
3062- Cygwin: Support for shared libraries, Tkinter, and sockets.
3063
3064- SunOS 4.1.4_JL: Fix test for directory existence in configure.
3065
3066Tools and other miscellany
3067
3068- Removed debugging prints from main used with freeze.
3069
Tim Peters46446d62000-10-09 21:19:31 +00003070- IDLE auto-indent no longer crashes when it encounters Unicode
3071 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003072
3073What's new in 2.0 beta 2 (since beta 1)?
3074========================================
3075
3076Core language, builtins, and interpreter
3077
Tim Peters482c0212000-09-26 06:33:09 +00003078- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003079 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003080
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003081- Add -h and -V command line options to print the usage message and
3082 Python version number and exit immediately.
3083
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003084- eval() and exec accept Unicode objects as code parameters.
3085
3086- getattr() and setattr() now also accept Unicode objects for the
3087 attribute name, which are converted to strings using the default
3088 encoding before lookup.
3089
3090- Multiplication on string and Unicode now does proper bounds
3091 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
3092 string is too long."
3093
3094- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00003095 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003096
Jeremy Hylton1b618592000-09-26 05:32:36 +00003097
3098Standard library and extensions
3099
Guido van Rossum5b08f132001-04-16 02:05:23 +00003100- socket module: the OpenSSL code now adds support for RAND_status()
3101 and EGD (Entropy Gathering Device).
3102
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003103- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00003104 argument checking; it still takes no arguments.
3105
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003106- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003107
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003108- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003109
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003110- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003111
3112- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003113 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003114
3115- copy: Copy Unicode objects atomically.
3116
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003117- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003118
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003119- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003120
Fred Drake67233bc2000-09-26 16:40:27 +00003121- dbm: Add get() and setdefault() methods to dbm object. Add constant
3122 `library' to module that names the library used. Added doc strings
3123 and method names to error messages. Uses configure to determine
3124 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
3125 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003126
3127- distutils: Update to version 0.9.3.
3128
3129- dl: Add several dl.RTLD_ constants.
3130
3131- fpectl: Now supported on FreeBSD.
3132
3133- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
3134 found by the collector will be saved in gc.garbage. This is useful
3135 for debugging a program that creates reference cycles.
3136
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003137- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00003138 of HTTP class. Do not close socket on zero-length response. Do not
3139 crash when server sends invalid content-length header.
3140
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003141- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003142
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003143- marshal: When reading a short, sign-extend on platforms where shorts
3144 are bigger than 16 bits. When reading a long, repair the unportable
3145 sign extension that was being done for 64-bit machines. (It assumed
3146 that signed right shift sign-extends.)
3147
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003148- operator: Add contains(), invert(), __invert__() as aliases for
3149 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003150
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003151- os: Add support for popen2() and popen3() on all platforms where
3152 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003153
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003154- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00003155 clicking on a file in Explorer (or passing the file name to the
3156 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003157
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003158- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00003159 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003160
3161- pickle: Now raises ValueError when an invalid pickle that contains
3162 a non-string repr where a string repr was expected. This behavior
3163 matches cPickle.
3164
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003165- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003166
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003167- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003168
3169- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003170 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003171 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003172
3173- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003174 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003175
3176- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00003177 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00003178 few cycles during startup since the first call to
3179 setdefaultencoding() will initialize the codec registry and the
3180 encodings package.
3181
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003182- socket: Support for size hint in readlines() method of object returned
3183 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003184
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003185- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00003186 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00003187 is followed by whitespace.
3188
Tim Petersa3a3a032000-11-30 05:22:44 +00003189- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003190
3191- struct: Check ranges for bytes and shorts.
3192
3193- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003194 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003195
3196- Tkinter: Image objects are now guaranteed to have unique ids. Set
3197 event.delta to zero if Tk version doesn't support mousewheel.
3198 Removed some debugging prints.
3199
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003200- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003201
Fred Drake67233bc2000-09-26 16:40:27 +00003202- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003203 which works around a bug in Norton AntiVirus 2000 that leads directly
3204 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003205
3206- xml: New version detection code allows PyXML to override standard
3207 XML package if PyXML version is greater than 0.6.1.
3208
Fred Drake64bb3802000-09-26 16:21:35 +00003209- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
3210 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
3211 tree only for nodes which are sufficiently interesting to a specific
3212 application. Does not provide the HTML-specific extensions. Still
3213 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003214
Fred Drake64bb3802000-09-26 16:21:35 +00003215- xml.sax: SAX 2 support for Python, including all the handler
3216 interfaces needed to process XML 1.0 compliant XML. Some
3217 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003218
Fred Drake64bb3802000-09-26 16:21:35 +00003219- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
3220 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003221
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003222
Jeremy Hylton1b618592000-09-26 05:32:36 +00003223C API
3224
3225- Add three new convenience functions for module initialization --
3226 PyModule_AddObject(), PyModule_AddIntConstant(), and
3227 PyModule_AddStringConstant().
3228
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003229- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00003230 removed and add #error to Python.h if NULL isn't defined after
3231 #include of stdio.h.
3232
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003233- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00003234 backwards compatibility (at the source level) with old extensions.
3235
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003236- A wrapper API was added for signal() and sigaction(). Instead of
3237 either function, always use PyOS_getsig() to get a signal handler
3238 and PyOS_setsig() to set one. A new convenience typedef
3239 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003240
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003241- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00003242 internal data buffer and size of a string object -- or the default
3243 encoded version of a Unicode object.
3244
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003245- PyString_Size() and PyString_AsString() accept Unicode objects.
3246
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003247- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00003248 exists). INT_MAX and LONG_MAX will always be defined, even if
3249 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003250
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003251- PyFloat_FromString takes a second argument, pend, that was
3252 effectively useless. It is now officially useless but preserved for
3253 backwards compatibility. If the pend argument is not NULL, *pend is
3254 set to NULL.
3255
3256- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
3257 for the attribute name. See note on getattr() above.
3258
3259- A few bug fixes to argument processing for Unicode.
3260 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
3261 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
3262 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00003263 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003264
3265- Py_BuildValue accepts B format (for bgen-generated code).
3266
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003267
Jeremy Hylton1b618592000-09-26 05:32:36 +00003268Internals
3269
3270- On Unix, fix code for finding Python installation directory so that
3271 it works when argv[0] is a relative path.
3272
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00003273- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003274 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00003275 rather than by generating a copy of the object.
3276
Tim Peters482c0212000-09-26 06:33:09 +00003277- Several of the internal Unicode tables are much smaller now, and
3278 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003279
Jeremy Hylton97693b02000-09-26 17:42:51 +00003280- In the garbage collector: Fixed bug in collection of tuples. Fixed
3281 bug that caused some instances to be removed from the container set
3282 while they were still live. Fixed parsing in gc.set_debug() for
3283 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003284
3285- Fixed refcount problem in instance deallocation that only occurred
3286 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
3287
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003288- On Windows, getpythonregpath is now protected against null data in
3289 registry key.
3290
3291- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00003292 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003293
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003294
Jeremy Hylton1b618592000-09-26 05:32:36 +00003295Build and platform-specific issues
3296
3297- Better support of GNU Pth via --with-pth configure option.
3298
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003299- Python/C API now properly exposed to dynamically-loaded extension
3300 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003301
3302- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
3303 Don't define MS_SYNC to be zero when it is undefined. Added missing
3304 prototypes in posixmodule.c.
3305
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003306- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003307 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003308
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003309- Fix largefile support on older NetBSD systems and OpenBSD by adding
3310 define for TELL64.
3311
3312
3313Tools and other miscellany
3314
3315- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
3316
3317- freeze: The modulefinder now works with 2.0 opcodes.
3318
Tim Petersa3a3a032000-11-30 05:22:44 +00003319- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003320 Move hackery of sys.argv until after the Tk instance has been
3321 created, which allows the application-specific Tkinter
3322 initialization to be executed if present; also pass an explicit
3323 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00003324
Jeremy Hylton1b618592000-09-26 05:32:36 +00003325
3326What's new in 2.0 beta 1?
3327=========================
3328
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003329Source Incompatibilities
3330------------------------
3331
3332None. Note that 1.6 introduced several incompatibilities with 1.5.2,
3333such as single-argument append(), connect() and bind(), and changes to
3334str(long) and repr(float).
3335
3336
3337Binary Incompatibilities
3338------------------------
3339
3340- Third party extensions built for Python 1.5.x or 1.6 cannot be used
3341with Python 2.0; these extensions will have to be rebuilt for Python
33422.0.
3343
3344- On Windows, attempting to import a third party extension built for
3345Python 1.5.x or 1.6 results in an immediate crash; there's not much we
3346can do about this. Check your PYTHONPATH environment variable!
3347
3348- Python bytecode files (*.pyc and *.pyo) are not compatible between
3349releases.
3350
3351
3352Overview of Changes Since 1.6
3353-----------------------------
3354
3355There are many new modules (including brand new XML support through
3356the xml package, and i18n support through the gettext module); a list
3357of all new modules is included below. Lots of bugs have been fixed.
3358
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003359The process for making major new changes to the language has changed
3360since Python 1.6. Enhancements must now be documented by a Python
3361Enhancement Proposal (PEP) before they can be accepted.
3362
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003363There are several important syntax enhancements, described in more
3364detail below:
3365
3366 - Augmented assignment, e.g. x += 1
3367
3368 - List comprehensions, e.g. [x**2 for x in range(10)]
3369
3370 - Extended import statement, e.g. import Module as Name
3371
3372 - Extended print statement, e.g. print >> file, "Hello"
3373
3374Other important changes:
3375
3376 - Optional collection of cyclical garbage
3377
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003378Python Enhancement Proposal (PEP)
3379---------------------------------
3380
3381PEP stands for Python Enhancement Proposal. A PEP is a design
3382document providing information to the Python community, or describing
3383a new feature for Python. The PEP should provide a concise technical
3384specification of the feature and a rationale for the feature.
3385
3386We intend PEPs to be the primary mechanisms for proposing new
3387features, for collecting community input on an issue, and for
3388documenting the design decisions that have gone into Python. The PEP
3389author is responsible for building consensus within the community and
3390documenting dissenting opinions.
3391
3392The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003393
3394Augmented Assignment
3395--------------------
3396
3397This must have been the most-requested feature of the past years!
3398Eleven new assignment operators were added:
3399
Guido van Rossume905e952000-09-05 12:42:46 +00003400 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003401
3402For example,
3403
3404 A += B
3405
3406is similar to
3407
3408 A = A + B
3409
3410except that A is evaluated only once (relevant when A is something
3411like dict[index].attr).
3412
3413However, if A is a mutable object, A may be modified in place. Thus,
3414if A is a number or a string, A += B has the same effect as A = A+B
3415(except A is only evaluated once); but if a is a list, A += B has the
3416same effect as A.extend(B)!
3417
3418Classes and built-in object types can override the new operators in
3419order to implement the in-place behavior; the not-in-place behavior is
3420used automatically as a fallback when an object doesn't implement the
3421in-place behavior. For classes, the method name is derived from the
3422method name for the corresponding not-in-place operator by inserting
3423an 'i' in front of the name, e.g. __iadd__ implements in-place
3424__add__.
3425
3426Augmented assignment was implemented by Thomas Wouters.
3427
3428
3429List Comprehensions
3430-------------------
3431
3432This is a flexible new notation for lists whose elements are computed
3433from another list (or lists). The simplest form is:
3434
3435 [<expression> for <variable> in <sequence>]
3436
Guido van Rossum56db0952000-09-06 23:34:25 +00003437For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003438This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003439
3440You can also add a condition:
3441
3442 [<expression> for <variable> in <sequence> if <condition>]
3443
3444For example, [w for w in words if w == w.lower()] would yield the list
3445of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003446than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003447
3448You can also have nested for loops and more than one 'if' clause. For
3449example, here's a function that flattens a sequence of sequences::
3450
3451 def flatten(seq):
3452 return [x for subseq in seq for x in subseq]
3453
3454 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3455
3456This prints
3457
3458 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3459
3460List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003461Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003462
3463
3464Extended Import Statement
3465-------------------------
3466
3467Many people have asked for a way to import a module under a different
3468name. This can be accomplished like this:
3469
3470 import foo
3471 bar = foo
3472 del foo
3473
3474but this common idiom gets old quickly. A simple extension of the
3475import statement now allows this to be written as follows:
3476
3477 import foo as bar
3478
3479There's also a variant for 'from ... import':
3480
3481 from foo import bar as spam
3482
3483This also works with packages; e.g. you can write this:
3484
3485 import test.regrtest as regrtest
3486
3487Note that 'as' is not a new keyword -- it is recognized only in this
3488context (this is only possible because the syntax for the import
3489statement doesn't involve expressions).
3490
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003491Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003492
3493
3494Extended Print Statement
3495------------------------
3496
3497Easily the most controversial new feature, this extension to the print
3498statement adds an option to make the output go to a different file
3499than the default sys.stdout.
3500
3501For example, to write an error message to sys.stderr, you can now
3502write:
3503
3504 print >> sys.stderr, "Error: bad dog!"
3505
3506As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003507evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003508
3509 print >> None, "Hello world"
3510
3511is equivalent to
3512
3513 print "Hello world"
3514
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003515Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003516
3517
3518Optional Collection of Cyclical Garbage
3519---------------------------------------
3520
3521Python is now equipped with a garbage collector that can hunt down
3522cyclical references between Python objects. It's no replacement for
3523reference counting; in fact, it depends on the reference counts being
3524correct, and decides that a set of objects belong to a cycle if all
3525their reference counts can be accounted for from their references to
3526each other. This devious scheme was first proposed by Eric Tiedemann,
3527and brought to implementation by Neil Schemenauer.
3528
3529There's a module "gc" that lets you control some parameters of the
3530garbage collection. There's also an option to the configure script
3531that lets you enable or disable the garbage collection. In 2.0b1,
3532it's on by default, so that we (hopefully) can collect decent user
3533experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003534performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003535off by default in the final 2.0 release.
3536
3537
3538Smaller Changes
3539---------------
3540
3541A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3542map(None, seq1, seq2, ...) when the sequences have the same length;
3543i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3544the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003545zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003546
3547sys.version_info is a tuple (major, minor, micro, level, serial).
3548
3549Dictionaries have an odd new method, setdefault(key, default).
3550dict.setdefault(key, default) returns dict[key] if it exists; if not,
3551it sets dict[key] to default and returns that value. Thus:
3552
3553 dict.setdefault(key, []).append(item)
3554
3555does the same work as this common idiom:
3556
3557 if not dict.has_key(key):
3558 dict[key] = []
3559 dict[key].append(item)
3560
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003561There are two new variants of SyntaxError that are raised for
3562indentation-related errors: IndentationError and TabError.
3563
3564Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3565escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003566
3567The limits on the size of expressions and file in Python source code
3568have been raised from 2**16 to 2**32. Previous versions of Python
3569were limited because the maximum argument size the Python VM accepted
3570was 2**16. This limited the size of object constructor expressions,
3571e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3572limit was raised thanks to a patch by Charles Waldman that effectively
3573fixes the problem. It is now much more likely that you will be
3574limited by available memory than by an arbitrary limit in Python.
3575
3576The interpreter's maximum recursion depth can be modified by Python
3577programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3578limit is the maximum number of recursive calls that can be made by
3579Python code. The limit exists to prevent infinite recursion from
3580overflowing the C stack and causing a core dump. The default value is
35811000. The maximum safe value for a particular platform can be found
3582by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003583
3584New Modules and Packages
3585------------------------
3586
3587atexit - for registering functions to be called when Python exits.
3588
3589imputil - Greg Stein's alternative API for writing custom import
3590hooks.
3591
3592pyexpat - an interface to the Expat XML parser, contributed by Paul
3593Prescod.
3594
3595xml - a new package with XML support code organized (so far) in three
3596subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3597would fill a volume. There's a special feature whereby a
3598user-installed package named _xmlplus overrides the standard
3599xmlpackage; this is intended to give the XML SIG a hook to distribute
3600backwards-compatible updates to the standard xml package.
3601
3602webbrowser - a platform-independent API to launch a web browser.
3603
3604
Guido van Rossume905e952000-09-05 12:42:46 +00003605Changed Modules
3606---------------
3607
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003608array -- new methods for array objects: count, extend, index, pop, and
3609remove
3610
3611binascii -- new functions b2a_hex and a2b_hex that convert between
3612binary data and its hex representation
3613
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003614calendar -- Many new functions that support features including control
3615over which day of the week is the first day, returning strings instead
3616of printing them. Also new symbolic constants for days of week,
3617e.g. MONDAY, ..., SUNDAY.
3618
3619cgi -- FieldStorage objects have a getvalue method that works like a
3620dictionary's get method and returns the value attribute of the object.
3621
3622ConfigParser -- The parser object has new methods has_option,
3623remove_section, remove_option, set, and write. They allow the module
3624to be used for writing config files as well as reading them.
3625
3626ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003627optionally support the RFC 959 REST command.
3628
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003629gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003630
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003631httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3632the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003633
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003634locale -- implement getdefaultlocale for Win32 and Macintosh
3635
3636marshal -- no longer dumps core when marshaling deeply nested or
3637recursive data structures
3638
3639os -- new functions isatty, seteuid, setegid, setreuid, setregid
3640
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003641os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3642support under Unix.
3643
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003644os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003645
3646os.path -- fix semantics of os.path.commonprefix
3647
3648smtplib -- support for sending very long messages
3649
3650socket -- new function getfqdn()
3651
3652readline -- new functions to read, write and truncate history files.
3653The readline section of the library reference manual contains an
3654example.
3655
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003656select -- add interface to poll system call
3657
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003658shutil -- new copyfileobj function
3659
3660SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3661HTTP server.
3662
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003663Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003664
3665urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003666e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003667
3668whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003669
3670
3671Obsolete Modules
3672----------------
3673
3674None. However note that 1.6 made a whole slew of modules obsolete:
3675stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3676poly, zmod, strop, util, whatsound.
3677
3678
3679Changed, New, Obsolete Tools
3680----------------------------
3681
Tim Peters8b092332000-09-05 20:15:25 +00003682None.
Guido van Rossume905e952000-09-05 12:42:46 +00003683
3684
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003685C-level Changes
3686---------------
3687
3688Several cleanup jobs were carried out throughout the source code.
3689
3690All C code was converted to ANSI C; we got rid of all uses of the
3691Py_PROTO() macro, which makes the header files a lot more readable.
3692
3693Most of the portability hacks were moved to a new header file,
3694pyport.h; several other new header files were added and some old
3695header files were removed, in an attempt to create a more rational set
3696of header files. (Few of these ever need to be included explicitly;
3697they are all included by Python.h.)
3698
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003699Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003700and Win64, especially for the new Intel Itanium processor. Mick also
3701added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003702
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003703The C APIs to return an object's size have been update to consistently
3704use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3705previous versions, the abstract interfaces used PyXXX_Length and the
3706concrete interfaces used PyXXX_Size. The old names,
3707e.g. PyObject_Length, are still available for backwards compatibility
3708at the API level, but are deprecated.
3709
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003710The PyOS_CheckStack function has been implemented on Windows by
3711Fredrik Lundh. It prevents Python from failing with a stack overflow
3712on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003713
3714The GC changes resulted in creation of two new slots on object,
3715tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003716the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003717
3718The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003719C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003720
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003721PyErr_Format has been updated to automatically calculate the size of
3722the buffer needed to hold the formatted result string. This change
3723prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003724
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003725New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003726
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003727PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3728that are the same as their non-Ex counterparts except they take an
3729extra flag argument that tells them to close the file when done.
3730
3731XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003732
Tim Peters8b092332000-09-05 20:15:25 +00003733
3734Windows Changes
3735---------------
3736
3737New popen2/popen3/peopen4 in os module (see Changed Modules above).
3738
3739os.popen is much more usable on Windows 95 and 98. See Microsoft
3740Knowledge Base article Q150956. The Win9x workaround described there
3741is implemented by the new w9xpopen.exe helper in the root of your
3742Python installation. Note that Python uses this internally; it is not
3743a standalone program.
3744
3745Administrator privileges are no longer required to install Python
3746on Windows NT or Windows 2000. If you have administrator privileges,
3747Python's registry info will be written under HKEY_LOCAL_MACHINE.
3748Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003749under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003750uses of Python, but will prevent some advanced uses from working
3751(for example, running a Python script as an NT service, or possibly
3752from CGI).
3753
3754[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3755installer; instead, it installs the needed Tcl/Tk files directly in the
3756Python directory. If you already have a Tcl/Tk installation, this
3757wastes some disk space (about 4 Megs) but avoids problems with
3758conflicting Tcl/Tk installations, and makes it much easier for Python
3759to ensure that Tcl/Tk can find all its files.
3760
3761[This was new in 1.6] The Windows installer now installs by default in
3762\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3763
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003764
3765Updates to the changes between 1.5.2 and 1.6
3766--------------------------------------------
3767
3768The 1.6 NEWS file can't be changed after the release is done, so here
3769is some late-breaking news:
3770
3771New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3772and changes to getlocale() and setlocale().
3773
3774The new module is now enabled per default.
3775
3776It is not true that the encodings codecs cannot be used for normal
3777strings: the string.encode() (which is also present on 8-bit strings
3778!) allows using them for 8-bit strings too, e.g. to convert files from
3779cp1252 (Windows) to latin-1 or vice-versa.
3780
3781Japanese codecs are available from Tamito KAJIYAMA:
3782http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3783
3784
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003785======================================================================