blob: b877703afb16a957fb9d2c18f800ce2d3629abb6 [file] [log] [blame]
Tim Petersaf8446f2001-12-21 21:36:50 +00001What's New in Python 2.3 alpha 1?
2XXX Release date: DD-MMM-2002 XXX
3=================================
4
5Type/class unification and new-style classes
6
Guido van Rossume3438782002-08-12 03:42:03 +00007- Assignment to __class__ is disallowed if either the old and the new
8 class is a statically allocated type object (such as defined by an
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00009 extension module). This prevents anomalies like 2.__class__ = bool.
Guido van Rossume3438782002-08-12 03:42:03 +000010
11- New-style object creation and deallocation have been sped up
12 significantly; they are now faster than classic instance creation
13 and deallocation.
14
15- The __slots__ variable can now mention "private" names, and the
16 right thing will happen (e.g. __slots__ = ["__foo"]).
17
18- The built-ins slice() and buffer() are now callable types. The
19 types classobj (formerly class), code, function, instance, and
20 instancemethod (formerly instance-method), which have no built-in
21 names but are accessible through the types module, are now also
22 callable. The type dict-proxy is renamed to dictproxy.
23
24- Cycles going through the __class__ link of a new-style instance are
25 now detected by the garbage collector.
26
27- Classes using __slots__ are now properly garbage collected.
28 [SF bug 519621]
29
30- Tightened the __slots__ rules: a slot name must be a valid Python
31 identifier.
32
33- The constructor for the module type now requires a name argument and
34 takes an optional docstring argument. Previously, this constructor
35 ignored its arguments. As a consequence, deriving a class from a
36 module (not from the module type) is now illegal; previously this
37 created an unnamed module, just like invoking the module type did.
38 [SF bug 563060]
39
40- A new type object, 'basestring', is added. This is a common base type
41 for 'str' and 'unicode', and can be used instead of
42 types.StringTypes, e.g. to test whether something is "a string":
43 isinstance(x, basestring) is True for Unicode and 8-bit strings. This
44 is an abstract base class and cannot be instantiated directly.
45
46- Changed new-style class instantiation so that when C's __new__
47 method returns something that's not a C instance, its __init__ is
48 not called. [SF bug #537450]
49
50- Fixed super() to work correctly with class methods. [SF bug #535444]
51
52- If you try to pickle an instance of a class that has __slots__ but
53 doesn't define or override __getstate__, a TypeError is now raised.
54 This is done by adding a bozo __getstate__ to the class that always
55 raises TypeError. (Before, this would appear to be pickled, but the
56 state of the slots would be lost.)
57
Tim Petersaf8446f2001-12-21 21:36:50 +000058Core and builtins
59
Walter Dörwald3aeb6322002-09-02 13:14:32 +000060- Codec error handling callbacks (PEP 293) are implemented.
61 Error handling in unicode.encode or str.decode can now be customized.
62
Guido van Rossum45ec02a2002-08-19 21:43:18 +000063- A subtle change to the semantics of the built-in function intern():
64 interned strings are no longer immortal. You must keep a reference
65 to the return value intern() around to get the benefit.
66
Guido van Rossumf808b892002-08-16 03:38:10 +000067- Use of 'None' as a variable, argument or attribute name now
68 issues a SyntaxWarning. In the future, None may become a keyword.
69
Michael W. Hudsondd32a912002-08-15 14:59:02 +000070- SET_LINENO is gone. co_lnotab is now consulted to determine when to
71 call the trace function. C code that accessed f_lineno should call
72 PyCode_Addr2Line instead (f_lineno is still there, but not kept up
73 to date).
74
Guido van Rossum9be89462002-08-14 16:11:30 +000075- There's a new warning category, FutureWarning. This is used to warn
76 about a number of situations where the value or sign of an integer
77 result will change in Python 2.4 as a result of PEP 237 (integer
78 unification). The warnings implement stage B0 mentioned in that
79 PEP. The warnings are about the following situations:
80
81 - Octal and hex literals without 'L' prefix in the inclusive range
82 [0x80000000..0xffffffff]; these are currently negative ints, but
83 in Python 2.4 they will be positive longs with the same bit
84 pattern.
85
86 - Left shifts on integer values that cause the outcome to lose
87 bits or have a different sign than the left operand. To be
88 precise: x<<n where this currently doesn't yield the same value
89 as long(x)<<n; in Python 2.4, the outcome will be long(x)<<n.
90
91 - Conversions from ints to string that show negative values as
92 unsigned ints in the inclusive range [0x80000000..0xffffffff];
93 this affects the functions hex() and oct(), and the string
94 formatting codes %u, %o, %x, and %X. In Python 2.4, these will
95 show signed values (e.g. hex(-1) currently returns "0xffffffff";
96 in Python 2.4 it will return "-0x1").
97
Skip Montanaro979c74b2002-09-03 21:25:14 +000098 - The bits manipulated under the cover by sys.setcheckinterval() have
99 been changed. Both the check interval and the ticker used to be
100 per-thread values. They are now just a pair of global variables. In
101 addition, the default check interval was boosted from 10 to 100
Neal Norwitz7165af22002-09-05 21:42:24 +0000102 bytecode instructions. This may have some effect on systems that
103 relied on the old default value. In particular, in multi-threaded
104 applications which try to be highly responsive, response time will
105 increase by some (perhaps imperceptible) amount.
Skip Montanaro979c74b2002-09-03 21:25:14 +0000106
Tim Petersd64c1de2002-08-12 17:36:03 +0000107- When multiplying very large integers, a version of the so-called
108 Karatsuba algorithm is now used. This is most effective if the
109 inputs have roughly the same size. If they both have about N digits,
110 Karatsuba multiplication has O(N**1.58) runtime (the exponent is
111 log_base_2(3)) instead of the previous O(N**2). Measured results may
Tim Peters012c0a32002-08-16 03:40:07 +0000112 be better or worse than that, depending on platform quirks. Besides
113 the O() improvement in raw instruction count, the Karatsuba algorithm
114 appears to have much better cache behavior on extremely large integers
115 (starting in the ballpark of a million bits). Note that this is a
116 simple implementation, and there's no intent here to compete with,
117 e.g., GMP. It gives a very nice speedup when it applies, but a package
118 devoted to fast large-integer arithmetic should run circles around it.
Tim Peters5af4e6c2002-08-12 02:31:19 +0000119
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +0000120- u'%c' will now raise a ValueError in case the argument is an
121 integer outside the valid range of Unicode code point ordinals.
122
Guido van Rossumdeb09362002-08-09 17:16:30 +0000123- The tempfile module has been overhauled for enhanced security. The
124 mktemp() function is now deprecated; new, safe replacements are
125 mkstemp() (for files) and mkdtemp() (for directories), and the
126 higher-level functions NamedTemporaryFile() and TemporaryFile().
127 Use of some global variables in this module is also deprecated; the
128 new functions have keyword arguments to provide the same
129 functionality. All Lib, Tools and Demo modules that used the unsafe
130 interfaces have been updated to use the safe replacements. Thanks
131 to Zack Weinberg!
132
Guido van Rossumd81a9832002-08-09 15:57:34 +0000133- When x is an object whose class implements __mul__ and __rmul__,
134 1.0*x would correctly invoke __rmul__, but 1*x would erroneously
135 invoke __mul__. This was due to the sequence-repeat code in the int
136 type. This has been fixed now.
137
Barry Warsawd79f6832002-08-06 17:01:51 +0000138- Previously, "str1 in str2" required str1 to be a string of length 1.
139 This restriction has been relaxed to allow str1 to be a string of
140 any length. Thus "'el' in 'hello world'" returns True now.
141
Guido van Rossumb57089c2002-08-06 16:20:26 +0000142- File objects are now their own iterators. For a file f, iter(f) now
143 returns f (unless f is closed), and f.next() is similar to
144 f.readline() when EOF is not reached; however, f.next() uses a
145 readahead buffer that messes up the file position, so mixing
146 f.next() and f.readline() (or other methods) doesn't work right.
147 Calling f.seek() drops the readahead buffer, but other operations
148 don't. It so happens that this gives a nice additional speed boost
149 to "for line in file:"; the xreadlines method and corresponding
Guido van Rossumbffb2ef2002-08-09 17:17:07 +0000150 module are now obsolete. Thanks to Oren Tirosh!
Guido van Rossumb57089c2002-08-06 16:20:26 +0000151
Guido van Rossumde392d32002-08-05 14:17:20 +0000152- Encoding declarations (PEP 263, phase 1) have been implemented. A
153 comment of the form "# -*- coding: <encodingname> -*-" in the first
154 or second line of a Python source file indicates the encoding.
Martin v. Löwis00f1e3f2002-08-04 17:29:52 +0000155
Tim Petersf47630f2002-08-01 02:34:51 +0000156- list.sort() has a new implementation. While cross-platform results
157 may vary, and in data-dependent ways, this is much faster on many
158 kinds of partially ordered lists than the previous implementation,
159 and reported to be just as fast on randomly ordered lists on
160 several major platforms. This sort is also stable (if A==B and A
161 precedes B in the list at the start, A precedes B after the sort too),
162 although the language definition does not guarantee stability. A
163 potential drawback is that list.sort() may require temp space of
164 len(list)*2 bytes (*4 on a 64-bit machine). It's therefore possible
165 for list.sort() to raise MemoryError now, even if a comparison function
166 does not. See <http://www.python.org/sf/587076> for full details.
167
Guido van Rossum2d5389c2002-07-23 03:44:35 +0000168- All standard iterators now ensure that, once StopIteration has been
169 raised, all future calls to next() on the same iterator will also
170 raise StopIteration. There used to be various counterexamples to
171 this behavior, which could caused confusion or subtle program
172 breakage, without any benefits. (Note that this is still an
173 iterator's responsibility; the iterator framework does not enforce
174 this.)
175
Mark Hammondc0e35152002-07-16 01:32:30 +0000176- Ctrl+C handling on Windows has been made more consistent with
177 other platforms. KeyboardInterrupt can now reliably be caught,
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +0000178 and Ctrl+C at an interactive prompt no longer terminates the
Mark Hammondc0e35152002-07-16 01:32:30 +0000179 process under NT/2k/XP (it never did under Win9x). Ctrl+C will
Tim Peters5af4e6c2002-08-12 02:31:19 +0000180 interrupt time.sleep() in the main thread, and any child processes
181 created via the popen family (on win2k; we can't make win9x work
Mark Hammond8f3afc72002-08-10 06:26:31 +0000182 reliably) are also interrupted (as generally happens on for Linux/Unix.)
183 [SF bugs 231273, 439992 and 581232]
Mark Hammondc0e35152002-07-16 01:32:30 +0000184
Raymond Hettinger5a04aec2002-06-25 00:25:30 +0000185- Slices and repetitions of buffer objects now consistently return
186 a string. Formerly, strings would be returned most of the time,
187 but a buffer object would be returned when the repetition count
188 was one or when the slice range was all inclusive.
189
Walter Dörwald3430d702002-06-17 10:43:59 +0000190- Unicode objects in sys.path are no longer ignored but treated
191 as directory names.
192
Neal Norwitz1f68fc72002-06-14 00:50:42 +0000193- Fixed string.startswith and string.endswith builtin methods
194 so they accept negative indices. [SF bug 493951]
195
Guido van Rossumc5fe5eb2002-06-12 03:45:21 +0000196- Fixed a bug with a continue inside a try block and a yield in the
197 finally clause. [SF bug 567538]
198
Michael W. Hudson5efaf7e2002-06-11 10:55:12 +0000199- Most builtin sequences now support "extended slices", i.e. slices
Guido van Rossum2e82e712002-06-13 11:41:07 +0000200 with a third "stride" parameter. For example, "hello world"[::-1]
201 gives "dlrow olleh".
Michael W. Hudson5efaf7e2002-06-11 10:55:12 +0000202
Neal Norwitzd68f5172002-05-29 15:54:55 +0000203- A new warning PendingDeprecationWarning was added to provide
204 direction on features which are in the process of being deprecated.
205 The warning will not be printed by default. To see the pending
206 deprecations, use -Walways::PendingDeprecationWarning::
207 as a command line option or warnings.filterwarnings() in code.
208
Fred Draked0ba6362002-05-02 21:28:26 +0000209- Deprecated features of xrange objects have been removed as
210 promised. The start, stop, and step attributes and the tolist()
211 method no longer exist. xrange repetition and slicing have been
212 removed.
213
Guido van Rossum7dab2422002-04-26 19:40:56 +0000214- New builtin function enumerate(x), from PEP 279. Example:
215 enumerate("abc") is an iterator returning (0,"a"), (1,"b"), (2,"c").
216 The argument can be an arbitrary iterable object.
217
Neil Schemenauer89e3ee02002-04-26 01:58:53 +0000218- The assert statement no longer tests __debug__ at runtime. This means
219 that assert statements cannot be disabled by assigning a false value
220 to __debug__.
221
Walter Dörwald068325e2002-04-15 13:36:47 +0000222- A method zfill() was added to str and unicode, that fills a numeric
223 string to the left with zeros. For example,
224 "+123".zfill(6) -> "+00123".
225
Guido van Rossum862fe3c2002-04-15 12:36:47 +0000226- Complex numbers supported divmod() and the // and % operators, but
227 these make no sense. Since this was documented, they're being
228 deprecated now.
229
Guido van Rossum26dd8302002-04-26 20:11:29 +0000230- String and unicode methods lstrip(), rstrip() and strip() now take
231 an optional argument that specifies the characters to strip. For
232 example, "Foo!!!?!?!?".rstrip("?!") -> "Foo".
Guido van Rossum49042042002-04-13 00:59:05 +0000233
Guido van Rossumc69343b2002-04-12 19:22:48 +0000234- Added a new dict method pop(key). This removes and returns the
235 value corresponding to key. [SF patch #539949]
236
Guido van Rossum47834462002-04-04 15:21:33 +0000237- A new built-in type, bool, has been added, as well as built-in
238 names for its two values, True and False. Comparisons and sundry
239 other operations that return a truth value have been changed to
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000240 return a bool instead. Read PEP 285 for an explanation of why this
Guido van Rossum47834462002-04-04 15:21:33 +0000241 is backward compatible.
242
Guido van Rossum95b62a62002-03-29 01:07:24 +0000243- Fixed two bugs reported as SF #535905: under certain conditions,
244 deallocating a deeply nested structure could cause a segfault in the
245 garbage collector, due to interaction with the "trashcan" code;
246 access to the current frame during destruction of a local variable
247 could access a pointer to freed memory.
248
Guido van Rossumfe0ca4a2002-06-18 21:20:13 +0000249- The optional object allocator ("pymalloc") has been enabled by
250 default. The recommended practice for memory allocation and
251 deallocation has been streamlined. A header file is included,
252 Misc/pymemcompat.h, which can be bundled with 3rd party extensions
253 and lets them use the same API with Python versions from 1.5.2
254 onwards.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000255
Martin v. Löwiscfeb3b62002-03-03 21:30:27 +0000256- PyErr_Display will provide file and line information for all exceptions
257 that have an attribute print_file_and_line, not just SyntaxErrors.
258
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000259- The UTF-8 codec will now encode and decode Unicode surrogates
260 correctly and without raising exceptions for unpaired ones.
261
Guido van Rossumadd88062002-08-15 14:01:14 +0000262- Universal newlines (PEP 278) is implemented. Briefly, using 'U'
263 instead of 'r' when opening a text file for reading changes the line
264 ending convention so that any of '\r', '\r\n', and '\n' is
265 recognized (even mixed in one file); all three are converted to
266 '\n', the standard Python line end character.
267
Neal Norwitz649b7592002-01-01 19:07:13 +0000268- file.xreadlines() now raises a ValueError if the file is closed:
269 Previously, an xreadlines object was returned which would raise
270 a ValueError when the xreadlines.next() method was called.
271
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000272- sys.exit() inadvertently allowed more than one argument.
Neal Norwitz0c766a02002-03-27 13:03:09 +0000273 An exception will now be raised if more than one argument is used.
274
Tim Petersaf8446f2001-12-21 21:36:50 +0000275Extension modules
276
Neal Norwitzb5673922002-09-05 21:48:07 +0000277- If the size passed to mmap.mmap() is larger than the length of the
278 file on non-Windows platforms, a ValueError is raised. [SF bug 585792]
279
Guido van Rossumb57089c2002-08-06 16:20:26 +0000280- The xreadlines module is slated for obsolescence.
281
Guido van Rossum79f0a102002-07-23 03:32:08 +0000282- The strptime function in the time module is now always available (a
283 Python implementation is used when the C library doesn't define it).
284
Guido van Rossum9562bcf2002-06-14 21:31:18 +0000285- The 'new' module is no longer an extension, but a Python module that
286 only exists for backwards compatibility. Its contents are no longer
287 functions but callable type objects.
288
Tim Peters81b92512002-04-29 01:37:32 +0000289- The bsddb.*open functions can now take 'None' as a filename.
Anthony Baxter83888952002-04-23 02:11:05 +0000290 This will create a temporary in-memory bsddb that won't be
Tim Peters81b92512002-04-29 01:37:32 +0000291 written to disk.
Anthony Baxter83888952002-04-23 02:11:05 +0000292
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000293- posix.lchown, posix.killpg, posix.mknod, and posix.getpgid have been
294 added where available.
Martin v. Löwis06a83e92002-04-14 10:19:44 +0000295
Martin v. Löwis2e64c342002-03-27 18:49:02 +0000296- The locale module now exposes the C library's gettext interface.
297
Tim Petersfbf74f22002-03-14 19:06:01 +0000298- A security hole ("double free") was found in zlib-1.1.3, a popular
299 third party compression library used by some Python modules. The
300 hole was quickly plugged in zlib-1.1.4, and the Windows build of
301 Python now ships with zlib-1.1.4.
302
Martin v. Löwis688357e2002-04-08 21:28:20 +0000303- pwd, grp, and resource return enhanced tuples now, with symbolic
304 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +0000305
Martin v. Löwis99866332002-03-01 10:27:01 +0000306- array.array is now a type object. A new format character
307 'u' indicates Py_UNICODE arrays. For those, .tounicode and
308 .fromunicode methods are available. Arrays now support __iadd__
309 and __imul__.
310
Neal Norwitze790eae2002-01-01 21:14:12 +0000311- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +0000312 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
313 is called.
314
Michael W. Hudson34f20ea2002-05-27 15:08:24 +0000315- signal.sigpending, signal.sigprocmask and signal.sigsuspend have
316 been added where available.
317
Skip Montanaro8e790e72002-09-03 13:25:17 +0000318- The sys module acquired a new attribute, api_version, which evaluates
319 to the value of the PYTHON_API_VERSION macro with which the
320 interpreter was compiled.
321
Tim Petersaf8446f2001-12-21 21:36:50 +0000322Library
323
Guido van Rossumd8ab35c2002-08-19 16:25:46 +0000324- New module: sets, defines the class Set that implements a mutable
325 set type using the keys of a dict to represent the set. There's
326 also a class ImmutableSet which is useful when you need sets of sets
327 or when you need to use sets as dict keys, and a class BaseSet which
328 is the base class of the two. (This is not documented yet, but
329 help(sets) gives a wealth of information.)
330
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +0000331- Added operator.pow(a,b) which is equivalent to a**b.
332
Tim Peters012c0a32002-08-16 03:40:07 +0000333- random.randrange(-sys.maxint-1, sys.maxint) no longer raises
334 OverflowError. That is, it now accepts any combination of 'start'
335 and 'stop' arguments so long as each is in the range of Python's
336 bounded integers.
337
Guido van Rossum4a57c332002-08-02 18:05:20 +0000338- New "algorithms" module: heapq, implements a heap queue. Thanks to
339 Kevin O'Connor for the code and François Pinard for an entertaining
340 write-up explaining the theory and practical uses of heaps.
341
Marc-André Lemburg58e2ff22002-07-12 14:40:04 +0000342- New encoding for the Palm OS character set: palmos.
343
Tim Peters943382c2002-07-07 03:59:34 +0000344- binascii.crc32() and the zipfile module had problems on some 64-bit
345 platforms. These have been fixed. On a platform with 8-byte C longs,
346 crc32() now returns a signed-extended 4-byte result, so that its value
347 as a Python int is equal to the value computed a 32-bit platform.
348
Martin v. Löwis7d650ca2002-06-30 15:05:00 +0000349- xml.dom.minidom.toxml and toprettyxml now take an optional encoding
350 argument.
351
Guido van Rossum9f7549b2002-06-10 21:39:42 +0000352- Some fixes in the copy module: when an object is copied through its
353 __reduce__ method, there was no check for a __setstate__ method on
354 the result [SF patch 565085]; deepcopy should treat instances of
355 custom metaclasses the same way it treats instances of type 'type'
356 [SF patch 560794].
357
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000358- Sockets now support timeout mode. After s.settimeout(T), where T is
359 a float expressing seconds, subsequent operations raise an exception
360 if they cannot be completed within T seconds. To disable timeout
Guido van Rossum79f0a102002-07-23 03:32:08 +0000361 mode, use s.settimeout(None). There's also a module function,
362 socket.setdefaulttimeout(T), which sets the default for all sockets
363 created henceforth.
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000364
365- getopt.gnu_getopt was added. This supports GNU-style option
366 processing, where options can be mixed with non-option arguments.
Martin v. Löwis446a25f2002-06-06 10:58:36 +0000367
Michael W. Hudsonb0dc1a32002-06-04 18:27:35 +0000368- Stop using strings for exceptions. String objects used for
369 exceptions are now classes deriving from Exception. The objects
370 changed were: Tkinter.TclError, bdb.BdbQuit, macpath.norm_error,
371 tabnanny.NannyNag, and xdrlib.Error.
Neal Norwitzb5b5a262002-06-04 17:14:07 +0000372
Walter Dörwald474458d2002-06-04 15:16:29 +0000373- Constants BOM_UTF8, BOM_UTF16, BOM_UTF16_LE, BOM_UTF16_BE,
374 BOM_UTF32, BOM_UTF32_LE and BOM_UTF32_BE that represent the Byte
375 Order Mark in UTF-8, UTF-16 and UTF-32 encodings for little and
376 big endian systems were added to the codecs module. The old names
377 BOM32_* and BOM64_* were off by a factor of 2.
378
Guido van Rossumf9257822002-06-18 20:43:18 +0000379- Added conversion functions math.degrees() and math.radians().
Raymond Hettinger87f59ee2002-05-13 04:17:32 +0000380
Raymond Hettinger9b1df1d2002-05-12 06:07:21 +0000381- ftplib.retrlines() now tests for callback is None rather than testing
382 for False. Was causing an error when given a callback object which
383 was callable but also returned len() as zero. The change may
384 create new breakage if the caller relied on the undocumented behavior
385 and called with callback set to [] or some other False value not
386 identical to None.
387
Tim Peters46c04e12002-05-05 20:40:00 +0000388- random.gauss() uses a piece of hidden state used by nothing else,
389 and the .seed() and .whseed() methods failed to reset it. In other
390 words, setting the seed didn't completely determine the sequence of
391 results produced by random.gauss(). It does now. Programs repeatedly
392 mixing calls to a seed method with calls to gauss() may see different
393 results now.
394
Fred Drake7f781c92002-05-01 20:33:53 +0000395- The pickle.Pickler class grew a clear_memo() method to mimic that
396 provided by cPickle.Pickler.
397
Tim Peters81b92512002-04-29 01:37:32 +0000398- difflib's SequenceMatcher class now does a dynamic analysis of
399 which elements are so frequent as to constitute noise. For
400 comparing files as sequences of lines, this generally works better
401 than the IS_LINE_JUNK function, and function ndiff's linejunk
402 argument defaults to None now as a result. A happy benefit is
403 that SequenceMatcher may run much faster now when applied
404 to large files with many duplicate lines (for example, C program
405 text with lots of repeated "}" and "return NULL;" lines).
406
Guido van Rossum256705b2002-04-23 13:29:43 +0000407- New Text.dump() method in Tkinter module.
408
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000409- New distutils commands for building packagers were added to
410 support pkgtool on Solaris and swinstall on HP-UX.
411
412- distutils now has a new abstract binary packager base class
413 command/bdist_packager, which simplifies writing packagers.
414 This will hopefully provide the missing bits to encourage
415 people to submit more packagers, e.g. for Debian, FreeBSD
416 and other systems.
417
Guido van Rossumf9257822002-06-18 20:43:18 +0000418- The UTF-16, -LE and -BE stream readers now raise a
419 NotImplementedError for all calls to .readline(). Previously, they
420 used to just produce garbage or fail with an encoding error --
421 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 +0000422 work well with these.
423
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000424- compileall now supports quiet operation.
425
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000426- The BaseHTTPServer now implements optional HTTP/1.1 persistent
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000427 connections.
428
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000429- socket module: the SSL support was broken out of the main
430 _socket module C helper and placed into a new _ssl helper
431 which now gets imported by socket.py if available and working.
432
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000433- encodings package: added aliases for all supported IANA character
434 sets
435
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000436- ftplib: to safeguard the user's privacy, anonymous login will use
437 "anonymous@" as default password, rather than the real user and host
438 name.
439
Fred Drake36736122002-01-10 13:50:31 +0000440- webbrowser: tightened up the command passed to os.system() so that
441 arbitrary shell code can't be executed because a bogus URL was
442 passed in.
443
Tim Peters11bd9942002-02-01 00:52:29 +0000444- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000445 gettext.find an optional all argument. Translations will now fallback
446 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000447
Martin v. Löwis9668b932002-01-12 11:27:42 +0000448- distutils bdist commands now offer a --skip-build option.
449
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000450- warnings.warn now accepts a Warning instance as first argument.
451
Fred Drakefed7e852002-04-04 19:36:15 +0000452- The xml.sax.expatreader.ExpatParser class will no longer create
453 circular references by using itself as the locator that gets passed
454 to the content handler implementation. [SF bug #535474]
455
Barry Warsaw47f3e2c2002-05-20 00:14:24 +0000456- The email.Parser.Parser class now properly parses strings regardless
457 of their line endings, which can be any of \r, \n, or \r\n (CR, LF,
458 or CRLF). Also, the Header class's constructor default arguments
459 has changed slightly so that an explicit maxlinelen value is always
460 honored.
461
Tim Petersaf8446f2001-12-21 21:36:50 +0000462Tools/Demos
463
Fred Drake40813b12002-08-05 15:24:19 +0000464- IDLE supports the new encoding declarations (PEP 263); it can also
465 deal with legacy 8-bit files if they use the locale's encoding. It
466 allows non-ASCII strings in the interactive shell and executes them
467 in the locale's encoding.
Martin v. Löwis98ce7b72002-08-05 15:11:26 +0000468
Marc-André Lemburg46260092002-04-04 16:17:11 +0000469- freeze.py now produces binaries which can import shared modules,
470 unlike before when this failed due to missing symbol exports in
471 the generated binary.
472
Tim Petersaf8446f2001-12-21 21:36:50 +0000473Build
474
Tim Petersf47630f2002-08-01 02:34:51 +0000475- The public Python C API will generally be declared using PyAPI_FUNC
Neal Norwitz1389f3e2002-07-22 13:21:10 +0000476 and PyAPI_DATA macros, while Python extension module init functions
477 will be declared with PyMODINIT_FUNC. DL_EXPORT/DL_IMPORT macros
478 are deprecated.
479
Tim Petersc6a3ff62002-07-08 22:11:52 +0000480- A bug was fixed that could cause COUNT_ALLOCS builds to segfault, or
481 get into infinite loops, when a new-style class got garbage-collected.
482 Unfortunately, to avoid this, the way COUNT_ALLOCS works requires
483 that new-style classes be immortal in COUNT_ALLOCS builds. Note that
484 COUNT_ALLOCS is not enabled by default, in either release or debug
485 builds, and that new-style classes are immortal only in COUNT_ALLOCS
486 builds.
487
Tim Peters943382c2002-07-07 03:59:34 +0000488- Compiling out the cyclic garbage collector is no longer an option.
489 The old symbol WITH_CYCLE_GC is now ignored, and Python.h arranges
490 that it's always defined (for the benefit of any extension modules
491 that may be conditionalizing on it). A bonus is that any extension
492 type participating in cyclic gc can choose to participate in the
493 Py_TRASHCAN mechanism now too; in the absence of cyclic gc, this used
494 to require editing the core to teach the trashcan mechanism about the
495 new type.
496
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000497- According to Annex F of the current C standard,
Tim Peters1de41bf2002-07-03 03:31:20 +0000498
499 The Standard C macro HUGE_VAL and its float and long double analogs,
500 HUGE_VALF and HUGE_VALL, expand to expressions whose values are
501 positive infinities.
502
503 Python only uses the double HUGE_VAL, and only to #define its own symbol
504 Py_HUGE_VAL. Some platforms have incorrect definitions for HUGE_VAL.
505 pyport.h used to try to worm around that, but the workarounds triggered
506 other bugs on other platforms, so we gave up. If your platform defines
507 HUGE_VAL incorrectly, you'll need to #define Py_HUGE_VAL to something
508 that works on your platform. The only instance of this I'm sure about
509 is on an unknown subset of Cray systems, described here:
510
511 http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm
512
513 Presumably 2.3a1 breaks such systems. If anyone uses such a system, help!
514
Martin v. Löwisa3fb4f72002-06-09 13:33:54 +0000515- The configure option --without-doc-strings can be used to remove the
516 doc strings from the builtin functions and modules; this reduces the
517 size of the executable.
518
Guido van Rossumadd88062002-08-15 14:01:14 +0000519- The universal newlines option (PEP 278) is on by default. On Unix
520 it can be disabled by passing --without-universal-newlines to the
521 configure script. On other platforms, remove
522 WITH_UNIVERSAL_NEWLINES from pyconfig.h.
Tim Peters639295f2002-04-21 07:30:30 +0000523
Martin v. Löwis1142de32002-03-29 16:28:31 +0000524- On Unix, a shared libpython2.3.so can be created with --enable-shared.
525
Tim Peters8deda702002-03-30 10:06:07 +0000526- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
527 preprocessor symbols were eliminated. The internal decisions they
528 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000529
Fred Drake7d28b732002-05-02 21:17:00 +0000530- The tools used to build the documentation now work under Cygwin as
531 well as Unix.
532
Skip Montanaro57454e52002-06-14 20:30:31 +0000533- The bsddb and dbm module builds have been changed to try and avoid version
534 skew problems and disable linkage with Berkeley DB 1.85 unless the
535 installer knows what s/he's doing. See the section on building these
536 modules in the README file for details.
537
Tim Petersaf8446f2001-12-21 21:36:50 +0000538C API
539
Guido van Rossum45ec02a2002-08-19 21:43:18 +0000540- The string object's layout has changed: the pointer member
541 ob_sinterned has been replaced by an int member ob_sstate. On some
542 platforms (e.g. most 64-bit systems) this may change the offset of
543 the ob_sval member, so as a precaution the API_VERSION has been
544 incremented. The apparently unused feature of "indirect interned
545 strings", supported by the ob_sinterned member, is gone. Interned
546 strings are now usually mortal; theres a new API,
547 PyString_InternImmortal() that creates immortal interned strings.
548 (The ob_sstate member can only take three values; however, while
549 making it a char saves a few bytes per string object on average, in
550 it also slowed things down a bit because ob_sval was no longer
551 aligned.)
552
Guido van Rossumfdb86482002-08-14 21:20:32 +0000553- The Py_InitModule*() functions now accept NULL for the 'methods'
554 argument. Modules without global functions are becoming more common
555 now that factories can be types rather than functions.
556
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +0000557- New C API PyUnicode_FromOrdinal() which exposes unichr() at C
558 level.
559
Thomas Heller085358a2002-07-29 14:27:41 +0000560- New functions PyErr_SetExcFromWindowsErr() and
561 PyErr_SetExcFromWindowsErrWithFilename(). Similar to
562 PyErr_SetFromWindowsErrWithFilename() and
563 PyErr_SetFromWindowsErr(), but they allow to specify
564 the exception type to raise. Available on Windows.
565
Tim Peters7c321a82002-07-09 02:57:01 +0000566- Py_FatalError() is now declared as taking a const char* argument. It
567 was previously declared without const. This should not affect working
568 code.
569
Martin v. Löwis01f94bd2002-05-08 08:44:21 +0000570- Added new macro PySequence_ITEM(o, i) that directly calls
571 sq_item without rechecking that o is a sequence and without
572 adjusting for negative indices.
573
Fred Draked0ba6362002-05-02 21:28:26 +0000574- PyRange_New() now raises ValueError if the fourth argument is not 1.
575 This is part of the removal of deprecated features of the xrange
576 object.
577
Guido van Rossum517c7d42002-04-26 02:49:14 +0000578- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
579 coercion if both arguments have the same type but this type has the
580 CHECKTYPES flag set. This is to better support proxies.
581
Neil Schemenauer9344b142002-04-12 23:00:08 +0000582- The type of tp_free has been changed from "void (*)(PyObject *)" to
583 "void (*)(void *)".
584
585- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
586
Guido van Rossum0986d822002-04-08 01:38:42 +0000587- A type can now inherit its metatype from its base type. Previously,
588 when PyType_Ready() was called, if ob_type was found to be NULL, it
589 was always set to &PyType_Type; now it is set to base->ob_type,
590 where base is tp_base, defaulting to &PyObject_Type.
591
592- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
593
Neil Schemenauerc9abc1d2002-05-08 14:14:41 +0000594- The PyCore_* family of APIs have been removed.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000595
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000596- The "u#" parser marker will now pass through Unicode objects as-is
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000597 without going through the buffer API.
598
Martin v. Löwis7198a522002-01-01 19:59:11 +0000599- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
600
Tim Peters10a3bb52001-12-25 19:07:38 +0000601- An old #define of ANY as void has been removed from pyport.h. This
602 hasn't been used since Python's pre-ANSI days, and the #define has
603 been marked as obsolete since then. SF bug 495548 says it created
604 conflicts with other packages, so keeping it around wasn't harmless.
605
Tim Petersaf8446f2001-12-21 21:36:50 +0000606- Because Python's magic number scheme broke on January 1st, we decided
607 to stop Python development. Thanks for all the fish!
608
Tim Petersfb05db22002-03-11 00:24:00 +0000609- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000610 scheme to a new one. See Python/import.c for details.
611
Tim Petersaf8446f2001-12-21 21:36:50 +0000612New platforms
613
Martin v. Löwisf90ae202002-06-11 06:22:31 +0000614- AtheOS is now supported.
615
Andrew MacIntyre161ad0e2002-08-04 07:25:58 +0000616- the EMX runtime environment on OS/2 is now supported.
617
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000618- GNU/Hurd is now supported.
619
Tim Petersaf8446f2001-12-21 21:36:50 +0000620Tests
621
622Windows
623
Tim Peters08e72952002-04-16 20:48:01 +0000624- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
625 of that has been fixed in the installer (disabled Wise's "delete in-
626 use files" uninstall option).
627
Guido van Rossum181e41a2002-04-06 00:23:25 +0000628- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
629
Tim Peters33187922002-04-04 20:02:04 +0000630- The installer now installs Start menu shortcuts under (the local
631 equivalent of) "All Users" when doing an Admin install.
632
Tim Petersfb05db22002-03-11 00:24:00 +0000633- file.truncate([newsize]) now works on Windows for all newsize values.
634 It used to fail if newsize didn't fit in 32 bits, reflecting a
635 limitation of MS _chsize (which is no longer used).
636
Tim Petersab034fa2002-02-01 11:27:43 +0000637- os.waitpid() is now implemented for Windows, and can be used to block
638 until a specified process exits. This is similar to, but not exactly
639 the same as, os.waitpid() on POSIX systems. If you're waiting for
640 a specific process whose pid was obtained from one of the spawn()
641 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000642 See the docs for details. The docs were changed to clarify that
643 spawn functions return, and waitpid requires, a process handle on
644 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000645
Tim Peters11bd9942002-02-01 00:52:29 +0000646- New tempfile.TemporaryFile implementation for Windows: this doesn't
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000647 need a TemporaryFileWrapper wrapper anymore, and should be immune
Tim Peters11bd9942002-02-01 00:52:29 +0000648 to a nasty problem: before 2.3, if you got a temp file on Windows, it
649 got wrapped in an object whose close() method first closed the
650 underlying file, then deleted the file. This usually worked fine.
651 However, the spawn family of functions on Windows create (at a low C
652 level) the same set of open files in the spawned process Q as were
653 open in the spawning process P. If a temp file f was among them, then
654 doing f.close() in P first closed P's C-level file handle on f, but Q's
655 C-level file handle on f remained open, so the attempt in P to delete f
656 blew up with a "Permission denied" error (Windows doesn't allow
657 deleting open files). This was surprising, subtle, and difficult to
658 work around.
659
660- The os module now exports all the symbolic constants usable with the
661 low-level os.open() on Windows: the new constants in 2.3 are
662 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
663 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
664 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
665 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
666 (so specify both if you want both; note that neither is useful unless
667 specified with O_CREAT too).
668
Tim Petersaf8446f2001-12-21 21:36:50 +0000669Mac
670
671
Tim Peters909c0912001-12-14 23:16:18 +0000672What's New in Python 2.2 final?
673Release date: 21-Dec-2001
674===============================
675
676Type/class unification and new-style classes
677
Barry Warsaw52acb492001-12-21 20:04:22 +0000678- pickle.py, cPickle: allow pickling instances of new-style classes
679 with a custom metaclass.
680
Tim Peters909c0912001-12-14 23:16:18 +0000681Core and builtins
682
Barry Warsaw52acb492001-12-21 20:04:22 +0000683- weakref proxy object: when comparing, unwrap both arguments if both
684 are proxies.
685
Tim Peters909c0912001-12-14 23:16:18 +0000686Extension modules
687
Barry Warsaw52acb492001-12-21 20:04:22 +0000688- binascii.b2a_base64(): fix a potential buffer overrun when encoding
689 very short strings.
690
691- cPickle: the obscure "fast" mode was suspected of causing stack
692 overflows on the Mac. Hopefully fixed this by setting the recursion
693 limit much smaller. If the limit is too low (it only affects
694 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
695 when compiling cPickle.c (or in pyconfig.h).
696
Tim Peters909c0912001-12-14 23:16:18 +0000697Library
698
Barry Warsaw52acb492001-12-21 20:04:22 +0000699- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
700 close or delete time).
701
702- rfc822.py: fixed a bug where the address '<>' was converted to None
703 instead of an empty string (also fixes the email.Utils module).
704
705- xmlrpclib.py: version 1.0.0; uses precision for doubles.
706
707- test suite: the pickle and cPickle tests were not executing any code
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000708 when run from the standard regression test.
Barry Warsaw52acb492001-12-21 20:04:22 +0000709
Tim Peters909c0912001-12-14 23:16:18 +0000710Tools/Demos
711
712Build
713
714C API
715
716New platforms
717
718Tests
719
720Windows
721
Barry Warsaw52acb492001-12-21 20:04:22 +0000722- distutils package: fixed broken Windows installers (bdist_wininst).
723
724- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
725 instances are deleted at process exit time.
726
727- socket.py: prevent mysterious warnings when socket instances are
728 deleted at process exit time.
729
730- posixmodule.c: fix a Windows crash with stat() of a filename ending
731 in backslash.
732
Tim Peters909c0912001-12-14 23:16:18 +0000733Mac
734
Barry Warsaw52acb492001-12-21 20:04:22 +0000735- The Carbon toolbox modules have been upgraded to Universal Headers
736 3.4, and experimental CoreGraphics and CarbonEvents modules have
737 been added. All only for framework-enabled MacOSX.
738
Tim Peters909c0912001-12-14 23:16:18 +0000739
Tim Peters6272dfd2001-12-13 19:34:00 +0000740What's New in Python 2.2c1?
741Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000742===========================
743
744Type/class unification and new-style classes
745
Barry Warsaw06557452001-12-14 20:47:12 +0000746- Guido's tutorial introduction to the new type/class features has
747 been extensively updated. See
748
749 http://www.python.org/2.2/descrintro.html
750
751 That remains the primary documentation in this area.
752
Guido van Rossum33bab012001-12-05 22:45:48 +0000753- Fixed a leak: instance variables declared with __slots__ were never
754 deleted!
755
Guido van Rossum4b800852001-12-03 00:54:52 +0000756- The "delete attribute" method of descriptor objects is called
757 __delete__, not __del__. In previous releases, it was mistakenly
758 called __del__, which created an unfortunate overloading condition
759 with finalizers. (The "get attribute" and "set attribute" methods
760 are still called __get__ and __set__, respectively.)
761
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000762- Some subtle issues with the super built-in were fixed:
763
764 (a) When super itself is subclassed, its __get__ method would still
765 return an instance of the base class (i.e., of super).
766
767 (b) super(C, C()).__class__ would return C rather than super. This
768 is confusing. To fix this, I decided to change the semantics of
769 super so that it only applies to code attributes, not to data
770 attributes. After all, overriding data attributes is not
771 supported anyway.
772
773 (c) The __get__ method didn't check whether the argument was an
774 instance of the type used in creation of the super instance.
775
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000776- Previously, hash() of an instance of a subclass of a mutable type
777 (list or dictionary) would return some value, rather than raising
778 TypeError. This has been fixed. Also, directly calling
779 dict.__hash__ and list.__hash__ now raises the same TypeError
780 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000781
Guido van Rossumd331cb52001-12-05 19:46:42 +0000782- New-style objects now support deleting their __dict__. This is for
783 all intents and purposes equivalent to assigning a brand new empty
784 dictionary, but saves space if the object is not used further.
785
Tim Petersb3c9af12001-11-17 00:21:57 +0000786Core and builtins
787
Tim Peters3caca232001-12-06 06:23:26 +0000788- -Qnew now works as documented in PEP 238: when -Qnew is passed on
789 the command line, all occurrences of "/" use true division instead
790 of classic division. See the PEP for details. Note that "all"
791 means all instances in library and 3rd-party modules, as well as in
792 your own code. As the PEP says, -Qnew is intended for use only in
793 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000794 Note that test_coercion.py in the standard Python test suite fails
795 under -Qnew; this is expected, and won't be repaired until true
796 division becomes the default (in the meantime, test_coercion is
797 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000798
Fred Drake6c01e252001-12-14 17:08:12 +0000799- complex() now only allows the first argument to be a string
800 argument, and raises TypeError if either the second arg is a string
801 or if the second arg is specified when the first is a string.
802
Tim Petersb3c9af12001-11-17 00:21:57 +0000803Extension modules
804
Martin v. Löwis560da622001-11-24 09:24:51 +0000805- gc.get_referents was renamed to gc.get_referrers.
806
Tim Petersb3c9af12001-11-17 00:21:57 +0000807Library
808
Tim Peters25059d32001-12-07 20:35:43 +0000809- Functions in the os.spawn() family now release the global interpreter
810 lock around calling the platform spawn. They should always have done
811 this, but did not before 2.2c1. Multithreaded programs calling
812 an os.spawn function with P_WAIT will no longer block all Python threads
813 until the spawned program completes. It's possible that some programs
814 relies on blocking, although more likely by accident than by design.
815
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000816- webbrowser defaults to netscape.exe on OS/2 now.
817
Martin v. Löwis652e1912001-11-25 14:50:56 +0000818- Tix.ResizeHandle exposes detach_widget, hide, and show.
819
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000820- The charset alias windows_1252 has been added.
821
Barry Warsaw06557452001-12-14 20:47:12 +0000822- types.StringTypes is a tuple containing the defined string types;
823 usually this will be (str, unicode), but if Python was compiled
824 without Unicode support it will be just (str,).
825
826- The pulldom and minidom modules were synchronized to PyXML.
827
Tim Petersb3c9af12001-11-17 00:21:57 +0000828Tools/Demos
829
Barry Warsaw06557452001-12-14 20:47:12 +0000830- A new script called Tools/scripts/google.py was added, which fires
831 off a search on Google.
832
Tim Petersb3c9af12001-11-17 00:21:57 +0000833Build
834
Barry Warsaw06557452001-12-14 20:47:12 +0000835- Note that release builds of Python should arrange to define the
836 preprocessor symbol NDEBUG on the command line (or equivalent).
837 In the 2.2 pre-release series we tried to define this by magic in
838 Python.h instead, but it proved to cause problems for extension
839 authors. The Unix, Windows and Mac builds now all define NDEBUG in
840 release builds via cmdline (or equivalent) instead. Ports to
841 other platforms should do likewise.
842
Jack Jansen1999ef42001-12-06 21:47:20 +0000843- It is no longer necessary to use --with-suffix when building on a
844 case-insensitive file system (such as Mac OS X HFS+). In the build
845 directory an extension is used, but not in the installed python.
846
Tim Petersb3c9af12001-11-17 00:21:57 +0000847C API
848
Tim Petersf582b822001-12-11 18:51:08 +0000849- New function PyDict_MergeFromSeq2() exposes the builtin dict
850 constructor's logic for updating a dictionary from an iterable object
851 producing key-value pairs.
852
Tim Peterscffed4b2001-11-29 03:26:37 +0000853- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000854 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000855 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
856 dump core in some bad cases. This has been repaired. As a result,
857 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
858 previously went unchallenged.
859
Tim Petersb3c9af12001-11-17 00:21:57 +0000860New platforms
861
862Tests
863
864Windows
865
866Mac
867
Jack Jansenffa260f2001-12-06 21:14:00 +0000868- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
869 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000870
Barry Warsaw06557452001-12-14 20:47:12 +0000871- Changed logic for finding python home in Mac OS X framework Pythons.
872 Now sys.executable points to the executable again, in stead of to
873 the shared library. The latter is used only for locating the python
874 home.
875
876
Tim Peters84362bc2001-10-19 17:55:30 +0000877What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000878Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000879===========================
880
881Type/class unification and new-style classes
882
Guido van Rossum3d27df02001-11-15 20:27:54 +0000883- Multiple inheritance mixing new-style and classic classes in the
884 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000885
886 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000887 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000888
889 The MRO (method resolution order) for each base class is respected
890 according to its kind, but the MRO for the derived class is computed
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000891 using new-style MRO rules if any base class is a new-style class.
Tim Peters76f7fe32001-11-15 20:02:21 +0000892 This needs to be documented.
893
Tim Petersa427a2b2001-10-29 22:25:45 +0000894- The new builtin dictionary() constructor, and dictionary type, have
895 been renamed to dict. This reflects a decade of common usage.
896
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000897- dict() now accepts an iterable object producing 2-sequences. For
898 example, dict(d.items()) == d for any dictionary d. The argument,
899 and the elements of the argument, can be any iterable objects.
900
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000901- New-style classes can now have a __del__ method, which is called
902 when the instance is deleted (just like for classic classes).
903
Guido van Rossum12d955c2001-10-26 14:56:06 +0000904- Assignment to object.__dict__ is now possible, for objects that are
905 instances of new-style classes that have a __dict__ (unless the base
906 class forbids it).
907
Guido van Rossumc8e56452001-10-22 00:43:43 +0000908- Methods of built-in types now properly check for keyword arguments
909 (formerly these were silently ignored). The only built-in methods
910 that take keyword arguments are __call__, __init__ and __new__.
911
Guido van Rossum86443212001-10-27 22:28:54 +0000912- The socket function has been converted to a type; see below.
913
Tim Peters84362bc2001-10-19 17:55:30 +0000914Core and builtins
915
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000916- Assignment to __debug__ raises SyntaxError at compile-time. This
917 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000918 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000919
Guido van Rossum12d955c2001-10-26 14:56:06 +0000920- Clarified the error messages for unsupported operands to an operator
921 (like 1 + '').
922
Tim Peters84362bc2001-10-19 17:55:30 +0000923Extension modules
924
Tim Peters5ebfd362001-11-13 23:11:19 +0000925- mmap has a new keyword argument, "access", allowing a uniform way for
926 both Windows and Unix users to create read-only, write-through and
927 copy-on-write memory mappings. This was previously possible only on
928 Unix. A new keyword argument was required to support this in a
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000929 uniform way because the mmap() signatures had diverged across
Tim Peters5ebfd362001-11-13 23:11:19 +0000930 platforms. Thanks to Jay T Miller for repairing this!
931
Tim Peters169ded02001-11-03 19:57:21 +0000932- By default, the gc.garbage list now contains only those instances in
933 unreachable cycles that have __del__ methods; in 2.1 it contained all
934 instances in unreachable cycles. "Instances" here has been generalized
935 to include instances of both new-style and old-style classes.
936
Guido van Rossum12d955c2001-10-26 14:56:06 +0000937- The socket module defines a new method for socket objects,
938 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000939 send() until all data has been sent. Also, the socket function has
940 been converted to a subclassable type, like list and tuple (etc.)
941 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000942
943- Various bugfixes to the curses module. There is now a test suite
944 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000945
Guido van Rossum692adf12001-10-30 03:03:03 +0000946- binascii.b2a_base64 no longer places an arbitrary restriction of 57
947 bytes on its input.
948
Tim Peters84362bc2001-10-19 17:55:30 +0000949Library
950
Tim Peters5ebfd362001-11-13 23:11:19 +0000951- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000952 convenience function.
953
Tim Peters75335872001-11-03 19:35:43 +0000954- Symbolic group names in regular expressions must be unique. For
955 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
956 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000957 Python 2.2 detects this error at regexp compilation time;
958 previously, the error went undetected, and results were
959 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
960 pattern.subn() methods have been rewritten in C. Also, an
961 experimental function/method finditer() has been added, which works
962 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000963
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000964- Tix exposes more commands through the classes DirSelectBox,
965 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
966 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
967 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
968
Tim Peters98791af2001-10-23 01:59:54 +0000969- Traceback objects are now scanned by cyclic garbage collection, so
970 cycles created by casual use of sys.exc_info() no longer cause
971 permanent memory leaks (provided garbage collection is enabled).
972
Guido van Rossum49192142001-10-24 20:51:44 +0000973- os.extsep -- a new variable needed by the RISCOS support. It is the
974 separator used by extensions, and is '.' on all platforms except
975 RISCOS, where it is '/'. There is no need to use this variable
976 unless you have a masochistic desire to port your code to RISCOS.
977
Barry Warsaw012852b2001-11-16 16:17:27 +0000978- mimetypes.py has optional support for non-standard, but commonly
979 found types. guess_type() and guess_extension() now accept an
980 optional `strict' flag, defaulting to true, which controls whether
981 recognize non-standard types or not. A few non-standard types we
982 know about have been added. Also, when run as a script, there are
983 new -l and -e options.
984
985- statcache is now deprecated.
986
987- email.Utils.formatdate() now produces the preferred RFC 2822 style
988 dates with numeric timezones (it used to produce obsolete dates
989 hard coded to "GMT" timezone). An optional `localtime' flag is
990 added to produce dates in the local timezone, with daylight savings
991 time properly taken into account.
992
993- In pickle and cPickle, instead of masking errors in load() by
994 transforming them into SystemError, we let the original exception
995 propagate out. Also, implement support for __safe_for_unpickling__
996 in pickle, as it already was supported in cPickle.
997
Tim Peters84362bc2001-10-19 17:55:30 +0000998Tools/Demos
999
1000Build
1001
Barry Warsaw012852b2001-11-16 16:17:27 +00001002- The dbm module is built using libdb1 if available. The bsddb module
1003 is built with libdb3 if available.
1004
1005- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
1006
Tim Peters84362bc2001-10-19 17:55:30 +00001007C API
1008
Tim Peters1fc240e2001-10-26 05:06:50 +00001009- New function PySequence_Fast_GET_SIZE() returns the size of a non-
1010 NULL result from PySequence_Fast(), more quickly than calling
1011 PySequence_Size().
1012
Barry Warsaw012852b2001-11-16 16:17:27 +00001013- New argument unpacking function PyArg_UnpackTuple() added.
1014
1015- New functions PyObject_CallFunctionObjArgs() and
1016 PyObject_CallMethodObjArgs() have been added to make it more
1017 convenient and efficient to call functions and methods from C.
1018
1019- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
1020 possible that this will propagate errors it didn't before.
1021
1022- New function PyObject_CheckReadBuffer(), which returns true if its
1023 argument supports the single-segment readable buffer interface.
1024
Tim Peters84362bc2001-10-19 17:55:30 +00001025New platforms
1026
Guido van Rossum86443212001-10-27 22:28:54 +00001027- We've finally confirmed that this release builds on HP-UX 11.00,
1028 *with* threads, and passes the test suite.
1029
Tim Peters7a33d8b2001-11-05 02:51:07 +00001030- Thanks to a series of patches from Michael Muller, Python may build
1031 again under OS/2 Visual Age C++.
1032
Guido van Rossum49192142001-10-24 20:51:44 +00001033- Updated RISCOS port by Dietmar Schwertberger.
1034
Tim Peters84362bc2001-10-19 17:55:30 +00001035Tests
1036
Andrew M. Kuchling15e03532001-10-22 16:37:10 +00001037- Added a test script for the curses module. It isn't run automatically;
1038 regrtest.py must be run with '-u curses' to enable it.
1039
Tim Peters84362bc2001-10-19 17:55:30 +00001040Windows
1041
Barry Warsaw012852b2001-11-16 16:17:27 +00001042Mac
1043
1044- PythonScript has been moved to unsupported and is slated to be
1045 removed completely in the next release.
1046
1047- It should now be possible to build applets that work on both OS9 and
1048 OSX.
1049
1050- The core is now linked with CoreServices not Carbon; as a side
1051 result, default 8bit encoding on OSX is now ASCII.
1052
1053- Python should now build on OSX 10.1.1
1054
Tim Peters84362bc2001-10-19 17:55:30 +00001055
Tim Petersabf925f2001-09-28 21:53:42 +00001056What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +00001057Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +00001058===========================
1059
1060Type/class unification and new-style classes
1061
Guido van Rossum687ae002001-10-15 22:03:32 +00001062- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001063 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +00001064 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001065 remains: the __dict__ of a new-style class is a read-only proxy; you
1066 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +00001067 __defined__ attribute of new-style types no longer exists, for lack
1068 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001069 future a __cache__ may be resurrected with a similar function, if I
1070 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +00001071
Tim Peters1c9ca872001-10-04 06:43:12 +00001072- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
1073 always returned None, even when there was a class docstring).
1074
1075- doctest now finds and runs docstrings attached to new-style classes,
1076 class methods, static methods, and properties.
1077
Guido van Rossum9074ef62001-10-16 21:34:49 +00001078Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +00001079
Guido van Rossuma8bcf802001-10-15 15:53:58 +00001080- A very subtle syntactical pitfall in list comprehensions was fixed.
1081 For example: [a+b for a in 'abc', for b in 'def']. The comma in
1082 this example is a mistake. Previously, this would silently let 'a'
1083 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
1084 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
1085 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
1086 Note that [a for a in <singleton>] is a convoluted way to say
1087 [<singleton>] anyway, so it's not like any expressiveness is lost.
1088
Guido van Rossum9074ef62001-10-16 21:34:49 +00001089- getattr(obj, name, default) now only catches AttributeError, as
1090 documented, rather than returning the default value for all
1091 exceptions (which could mask bugs in a __getattr__ hook, for
1092 example).
1093
Fred Drakecb7a6b52001-10-22 18:41:51 +00001094- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +00001095 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001096 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +00001097 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +00001098
Guido van Rossum1c486092001-10-19 02:05:35 +00001099- unicode(obj) now behaves more like str(obj), accepting arbitrary
1100 objects, and calling a __unicode__ method if it exists.
1101 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +00001102 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +00001103
Barry Warsawf6fb1712001-10-19 05:35:40 +00001104- isinstance() now allows any object as the first argument and a
1105 class, a type or something with a __bases__ tuple attribute for the
1106 second argument. The second argument may also be a tuple of a
1107 class, type, or something with __bases__, in which case isinstance()
1108 will return true if the first argument is an instance of any of the
1109 things contained in the second argument tuple. E.g.
1110
1111 isinstance(x, (A, B))
1112
1113 returns true if x is an instance of A or B.
1114
Guido van Rossum9074ef62001-10-16 21:34:49 +00001115Extension modules
1116
1117- thread.start_new_thread() now returns the thread ID (previously None).
1118
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001119- binascii has now two quopri support functions, a2b_qp and b2a_qp.
1120
Guido van Rossumc524d952001-10-19 01:31:59 +00001121- readline now supports setting the startup_hook and the
1122 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +00001123
Guido van Rossumc524d952001-10-19 01:31:59 +00001124- os and posix supports chroot(), setgroups() and unsetenv() where
1125 available. The stat(), fstat(), statvfs() and fstatvfs() functions
1126 now return "pseudo-sequences" -- the various fields can now be
1127 accessed as attributes (e.g. os.stat("/").st_mtime) but for
1128 backwards compatibility they also behave as a fixed-length sequence.
1129 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +00001130 attributes.
1131
1132- time: localtime(), gmtime() and strptime() now return a
1133 pseudo-sequence similar to the os.stat() return value, with
1134 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +00001135
Guido van Rossum9074ef62001-10-16 21:34:49 +00001136- Decompression objects in the zlib module now accept an optional
1137 second parameter to decompress() that specifies the maximum amount
1138 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +00001139
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001140- optional SSL support in the socket module now exports OpenSSL
1141 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
1142 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +00001143 automatically seed its PRNG. Also, the keyfile and certfile
1144 arguments to socket.ssl() are now optional.
1145
1146- posixmodule (and by extension, the os module on POSIX platforms) now
1147 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001148
Guido van Rossum9074ef62001-10-16 21:34:49 +00001149Library
Guido van Rossum3c288632001-10-16 21:13:49 +00001150
Tim Peters7402f792001-10-02 03:53:41 +00001151- doctest now excludes functions and classes not defined by the module
1152 being tested, thanks to Tim Hochberg.
1153
Fred Drakecb7a6b52001-10-22 18:41:51 +00001154- HotShot, a new profiler implemented using a C-based callback, has
1155 been added. This substantially reduces the overhead of profiling,
1156 but it is still quite preliminary. Support modules and
1157 documentation will be added in upcoming releases (before 2.2 final).
1158
Guido van Rossumc4b09b42001-10-04 10:19:00 +00001159- profile now produces correct output in situations where an exception
1160 raised in Python is cleared by C code (e.g. hasattr()). This used
1161 to cause wrong output, including spurious claims of recursive
1162 functions and attribution of time spent to the wrong function.
1163
Tim Peters0a1fc4e2001-10-07 03:12:08 +00001164 The code and documentation for the derived OldProfile and HotProfile
1165 profiling classes was removed. The code hasn't worked for years (if
1166 you tried to use them, they raised exceptions). OldProfile
1167 intended to reproduce the behavior of the profiler Python used more
1168 than 7 years ago, and isn't interesting anymore. HotProfile intended
1169 to provide a faster profiler (but producing less information), and
1170 that's a worthy goal we intend to meet via a different approach (but
1171 without losing information).
1172
Tim Peterscce092d2001-10-09 05:31:56 +00001173- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +00001174 a much better system-specific calibration constant. The constant can
1175 now be specified in an instance constructor, or as a Profile class or
1176 instance variable, instead of by editing profile.py's source code.
1177 Calibration must still be done manually (see the docs for the profile
1178 module).
1179
1180 Note that Profile.calibrate() must be overriden by subclasses.
1181 Improving the accuracy required exploiting detailed knowledge of
1182 profiler internals; the earlier method abstracted away the details
1183 and measured a simplified model instead, but consequently computed
1184 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +00001185
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001186- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +00001187 which indicates whether output is intended for the header 'Q'
1188 encoding.
1189
Guido van Rossuma5343cc2001-10-18 18:02:07 +00001190- The SocketServer.ThreadingMixIn class now closes the request after
1191 finish_request() returns. (Not when it errors out though.)
1192
Barry Warsawf6fb1712001-10-19 05:35:40 +00001193- The nntplib module's NNTP.body() method has grown a `file' argument
1194 to allow saving the message body to a file.
1195
1196- The email package has added a class email.Parser.HeaderParser which
1197 only parses headers and does not recurse into the message's body.
1198 Also, the module/class MIMEAudio has been added for representing
1199 audio data (contributed by Anthony Baxter).
1200
1201- ftplib should be able to handle files > 2GB.
1202
1203- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
1204 ON, and OFF.
1205
Fred Drakecb7a6b52001-10-22 18:41:51 +00001206- xml.dom.minidom NodeList objects now support the length attribute
1207 and item() method as required by the DOM specifications.
1208
Guido van Rossumed554f62001-10-02 23:15:37 +00001209Tools/Demos
1210
1211- Demo/dns was removed. It no longer serves any purpose; a package
1212 derived from it is now maintained by Anthony Baxter, see
1213 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +00001214
Barry Warsawf6fb1712001-10-19 05:35:40 +00001215- The freeze tool has been made more robust, and two new options have
1216 been added: -X and -E.
1217
Tim Petersabf925f2001-09-28 21:53:42 +00001218Build
1219
Barry Warsawf6fb1712001-10-19 05:35:40 +00001220- configure will use CXX in LINKCC if CXX is used to build main() and
1221 the system requires to link a C++ main using the C++ compiler.
1222
Tim Petersabf925f2001-09-28 21:53:42 +00001223C API
1224
Guido van Rossum6c4bce32001-10-18 19:20:25 +00001225- The documentation for the tp_compare slot is updated to require that
1226 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
1227 not correct. This is not yet enforced but will be enforced in
1228 Python 2.3; even later, we may use -2 to indicate errors and +2 for
1229 "NotImplemented". Right now, -1 should be used for an error return.
1230
Tim Petersd38b1c72001-09-30 05:09:37 +00001231- PyLong_AsLongLong() now accepts int (as well as long) arguments.
1232 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
1233 as long) arguments.
1234
Guido van Rossum3c288632001-10-16 21:13:49 +00001235- PyThread_start_new_thread() now returns a long int giving the thread
1236 ID, if one can be calculated; it returns -1 for error, 0 if no
1237 thread ID is calculated (this is an incompatible change, but only
1238 the thread module used this API). This code has only really been
1239 tested on Linux and Windows; other platforms please beware (and
1240 report any bugs or strange behavior).
1241
Guido van Rossum1c486092001-10-19 02:05:35 +00001242- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
1243 input.
1244
Tim Petersabf925f2001-09-28 21:53:42 +00001245New platforms
1246
1247Tests
1248
1249Windows
1250
Tim Peters04cf1d32001-10-09 22:39:40 +00001251- Installer: If you install IDLE, and don't disable file-extension
1252 registration, a new "Edit with IDLE" context (right-click) menu entry
1253 is created for .py and .pyw files.
1254
Tim Peters1ce3cf72001-10-01 17:58:40 +00001255- The signal module now supports SIGBREAK on Windows, thanks to Steven
1256 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
1257 action remains to call Win32 ExitProcess(). This can be changed via
1258 signal.signal(). For example:
1259
1260 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
1261 # (SIGINT) behavior.
1262 import signal
1263 signal.signal(signal.SIGBREAK,
1264 signal.default_int_handler)
1265
1266 try:
1267 while 1:
1268 pass
1269 except KeyboardInterrupt:
1270 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
1271 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
1272 # program without the possibility for any Python-level cleanup).
1273 print "Clean exit"
1274
Tim Petersabf925f2001-09-28 21:53:42 +00001275
Tim Petersb07352e2001-09-08 01:25:47 +00001276What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001277Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +00001278===========================
1279
Guido van Rossum808eea72001-09-25 04:15:41 +00001280Type/class unification and new-style classes
1281
1282- pydoc and inspect are now aware of new-style classes;
1283 e.g. help(list) at the interactive prompt now shows proper
1284 documentation for all operations on list objects.
1285
1286- Applications using Jim Fulton's ExtensionClass module can now safely
1287 be used with Python 2.2. In particular, Zope 2.4.1 now works with
1288 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
1289 examples also work again. It is hoped that Gtk and Boost also work
1290 with 2.2a4 and beyond. (If you can confirm this, please write
1291 webmaster@python.org; if there are still problems, please open a bug
1292 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +00001293
Tim Peters66c1a522001-09-24 21:17:50 +00001294- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001295 These map to read-only attributes 'fget', 'fset', 'fdel', and '__doc__'
Tim Peters66c1a522001-09-24 21:17:50 +00001296 in the constructed property object. fget, fset and fdel weren't
1297 discoverable from Python in 2.2a3. __doc__ is new, and allows to
1298 associate a docstring with a property.
1299
Guido van Rossum808eea72001-09-25 04:15:41 +00001300- Comparison overloading is now more completely implemented. For
1301 example, a str subclass instance can properly be compared to a str
1302 instance, and it can properly overload comparison. Ditto for most
1303 other built-in object types.
1304
1305- The repr() of new-style classes has changed; instead of <type
1306 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
1307 *except* for built-in types, which are still rendered as <type
1308 'Foo'> (to avoid upsetting existing code that might parse or
1309 otherwise rely on repr() of certain type objects).
1310
1311- The repr() of new-style objects is now always <Foo object at XXX>;
1312 previously, it was sometimes <Foo instance at XXX>.
1313
1314- For new-style classes, what was previously called __getattr__ is now
1315 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001316 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +00001317 one in classic classes is defined which is called only if regular
1318 attribute access raises AttributeError; to catch *all* attribute
1319 access, you can use __getattribute__ (for new-style classes). If
1320 both are defined, __getattribute__ is called first, and if it raises
1321 AttributeError, __getattr__ is called.
1322
1323- The __class__ attribute of new-style objects can be assigned to.
1324 The new class must have the same C-level object layout as the old
1325 class.
1326
1327- The builtin file type can be subclassed now. In the usual pattern,
1328 "file" is the name of the builtin type, and file() is a new builtin
1329 constructor, with the same signature as the builtin open() function.
1330 file() is now the preferred way to open a file.
1331
1332- Previously, __new__ would only see sequential arguments passed to
1333 the type in a constructor call; __init__ would see both sequential
1334 and keyword arguments. This made no sense whatsoever any more, so
1335 now both __new__ and __init__ see all arguments.
1336
1337- Previously, hash() applied to an instance of a subclass of str or
1338 unicode always returned 0. This has been repaired.
1339
1340- Previously, an operation on an instance of a subclass of an
1341 immutable type (int, long, float, complex, tuple, str, unicode),
1342 where the subtype didn't override the operation (and so the
1343 operation was handled by the builtin type), could return that
1344 instance instead a value of the base type. For example, if s was of
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001345 a str subclass type, s[:] returned s as-is. Now it returns a str
Guido van Rossum808eea72001-09-25 04:15:41 +00001346 with the same value as s.
1347
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001348- Provisional support for pickling new-style objects has been added.
1349
Guido van Rossum808eea72001-09-25 04:15:41 +00001350Core
1351
Tim Peters2c9aa5e2001-09-23 04:06:05 +00001352- file.writelines() now accepts any iterable object producing strings.
1353
Marc-André Lemburgaefd7662001-09-20 12:59:37 +00001354- PyUnicode_FromEncodedObject() now works very much like
1355 PyObject_Str(obj) in that it tries to use __str__/tp_str
1356 on the object if the object is not a string or buffer. This
1357 makes unicode() behave like str() when applied to non-string/buffer
1358 objects.
1359
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001360- PyFile_WriteObject now passes Unicode objects to the file's write
1361 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +00001362 of a print statement must support Unicode objects, i.e. they must
1363 at least convert them into ASCII strings.
1364
Guido van Rossum624c8af2001-09-18 15:21:04 +00001365- Thread scheduling on Solaris should be improved; it is no longer
1366 necessary to insert a small sleep at the start of a thread in order
1367 to let other runnable threads be scheduled.
1368
Tim Petersb07352e2001-09-08 01:25:47 +00001369Library
1370
Marc-André Lemburgbf990172001-09-27 14:17:33 +00001371- StringIO.StringIO instances and cStringIO.StringIO instances support
1372 read character buffer compatible objects for their .write() methods.
1373 These objects are converted to strings and then handled as such
1374 by the instances.
1375
Barry Warsaw2f600732001-09-24 04:28:10 +00001376- The "email" package has been added. This is basically a port of the
1377 mimelib package <http://sf.net/projects/mimelib> with API changes
1378 and some implementations updated to use iterators and generators.
1379
Tim Peters8a9c2842001-09-22 21:30:22 +00001380- difflib.ndiff() and difflib.Differ.compare() are generators now. This
1381 restores the ability of Tools/scripts/ndiff.py to start producing output
1382 before the entire comparison is complete.
1383
Barry Warsaw58b072d2001-09-22 04:44:21 +00001384- StringIO.StringIO instances and cStringIO.StringIO instances support
1385 iteration just like file objects (i.e. their .readline() method is
1386 called for each iteration until it returns an empty string).
1387
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +00001388- The codecs module has grown four new helper APIs to access
1389 builtin codecs: getencoder(), getdecoder(), getreader(),
1390 getwriter().
1391
Guido van Rossum624c8af2001-09-18 15:21:04 +00001392- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
1393 simplifies writing XML RPC servers.
1394
Barry Warsaw647d5e82001-09-28 17:01:02 +00001395- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +00001396 after interpretation of symbolic links. On non-Unix systems, this
1397 is an alias for os.path.abspath().
1398
Tim Peters16a77ad2001-09-08 04:00:12 +00001399- operator.indexOf() (PySequence_Index() in the C API) now works with any
1400 iterable object.
1401
Guido van Rossum624c8af2001-09-18 15:21:04 +00001402- smtplib now supports various authentication and security features of
1403 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001404
Guido van Rossum624c8af2001-09-18 15:21:04 +00001405- hmac: a new module implementing keyed hashing for message
1406 authentication.
1407
1408- mimetypes now recognizes more extensions and file types. At the
1409 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001410
Guido van Rossum624c8af2001-09-18 15:21:04 +00001411- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001412 Python 2.2 bytecode generation. It has also been promoted from a
1413 Tool to a standard library package. (Tools/compiler still exists as
1414 a sample driver.)
1415
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001416Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +00001417
Tim Petersb07352e2001-09-08 01:25:47 +00001418Build
1419
Guido van Rossum624c8af2001-09-18 15:21:04 +00001420- Large file support (LFS) is now automatic when the platform supports
1421 it; no more manual configuration tweaks are needed. On Linux, at
1422 least, it's possible to have a system whose C library supports large
1423 files but whose kernel doesn't; in this case, large file support is
1424 still enabled but doesn't do you any good unless you upgrade your
1425 kernel or share your Python executable with another system whose
1426 kernel has large file support.
1427
1428- The configure script now supplies plausible defaults in a
1429 cross-compilation environment. This doesn't mean that the supplied
1430 values are always correct, or that cross-compilation now works
1431 flawlessly -- but it's a first step (and it shuts up most of
1432 autoconf's warnings about AC_TRY_RUN).
1433
1434- The Unix build is now a bit less chatty, courtesy of the parser
1435 generator. The build is completely silent (except for errors) when
1436 using "make -s", thanks to a -q option to setup.py.
1437
Tim Petersb07352e2001-09-08 01:25:47 +00001438C API
1439
Guido van Rossum624c8af2001-09-18 15:21:04 +00001440- The "structmember" API now supports some new flag bits to deny read
1441 and/or write access to attributes in restricted execution mode.
1442
Tim Petersb07352e2001-09-08 01:25:47 +00001443New platforms
1444
Guido van Rossum624c8af2001-09-18 15:21:04 +00001445- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1446 (http://familiar.handhelds.org).
1447
Tim Petersb07352e2001-09-08 01:25:47 +00001448Tests
1449
Tim Peters8a9c2842001-09-22 21:30:22 +00001450- The "classic" standard tests, which work by comparing stdout to
1451 an expected-output file under Lib/test/output/, no longer stop at
1452 the first mismatch. Instead the test is run to completion, and a
1453 variant of ndiff-style comparison is used to report all differences.
1454 This is much easier to understand than the previous style of reporting.
1455
1456- The unittest-based standard tests now use regrtest's test_main()
1457 convention, instead of running as a side-effect of merely being
1458 imported. This allows these tests to be run in more natural and
1459 flexible ways as unittests, outside the regrtest framework.
1460
1461- regrtest.py is much better integrated with unittest and doctest now,
1462 especially in regard to reporting errors.
1463
Tim Petersb07352e2001-09-08 01:25:47 +00001464Windows
1465
Guido van Rossum624c8af2001-09-18 15:21:04 +00001466- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001467 that support it (NTFS under Windows 2000). See "What's New in
1468 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001469
Tim Petersb07352e2001-09-08 01:25:47 +00001470
Tim Petersedc99312001-08-22 21:36:50 +00001471What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001472Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001473===========================
1474
1475Core
1476
Tim Peters9fffa3e2001-09-04 05:14:19 +00001477- Conversion of long to float now raises OverflowError if the long is too
1478 big to represent as a C double.
1479
Tim Peters32f453e2001-09-03 08:35:41 +00001480- The 3-argument builtin pow() no longer allows a third non-None argument
1481 if either of the first two arguments is a float, or if both are of
1482 integer types and the second argument is negative (in which latter case
1483 the arguments are converted to float, so this is really the same
1484 restriction).
1485
Tim Peters5d2b77c2001-09-03 05:47:38 +00001486- The builtin dir() now returns more information, and sometimes much
1487 more, generally naming all attributes of an object, and all attributes
1488 reachable from the object via its class, and from its class's base
1489 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1490 an empty list. In 2.2a3,
1491
1492 >>> dir([])
1493 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1494 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1495 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1496 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1497 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1498 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1499 'reverse', 'sort']
1500
1501 dir(module) continues to return only the module's attributes, though.
1502
Tim Petersbdee63f2001-09-02 03:40:59 +00001503- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001504 than raising OverflowError. This is a partial implementation of PEP
1505 237. You can use -Wdefault::OverflowWarning to enable a warning for
1506 this situation, and -Werror::OverflowWarning to revert to the old
1507 OverflowError exception.
1508
Guido van Rossum61c345f2001-09-04 03:26:15 +00001509- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001510 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001511 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1512 -Qold, meaning the / operator has its classic meaning and no
1513 warnings are issued. Using -Qwarn issues a run-time warning about
1514 all uses of classic division for int and long arguments; -Qwarnall
1515 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001516 (for use with fixdiv.py).
1517 [Note: the remainder of this paragraph (preserved below) became
1518 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1519 <obsolete>
1520 Using -Qnew is questionable; it turns on new division by default, but
1521 only in the __main__ module. You can usefully combine -Qwarn or
1522 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1523 warns about classic division everywhere else.
1524 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001525
Tim Petersbdee63f2001-09-02 03:40:59 +00001526- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001527 long, float, str, unicode, and tuple. (The types complex, list and
1528 dictionary can also be subclassed; this was introduced earlier.)
1529 Note that restrictions apply when subclassing immutable built-in
1530 types: you can only affect the value of the instance by overloading
1531 __new__. You can add mutable attributes, and the subclass instances
1532 will have a __dict__ attribute, but you cannot change the "value"
1533 (as implemented by the base class) of an immutable subclass instance
1534 once it is created.
1535
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001536- The dictionary constructor now takes an optional argument, a
1537 mapping-like object, and initializes the dictionary from its
1538 (key, value) pairs.
1539
Tim Petersbdee63f2001-09-02 03:40:59 +00001540- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001541 "cooperative super calls" in a multiple inheritance setting. For an
1542 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1543
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001544- A new built-in type, property, has been added. This enables the
1545 creation of "properties". These are attributes implemented by
1546 getter and setter functions (or only one of these for read-only or
1547 write-only attributes), without the need to override __getattr__.
1548 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001549
Tim Petersbdee63f2001-09-02 03:40:59 +00001550- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001551 liberalized, to allow leading zeroes. Examples of literals now
1552 legal that were SyntaxErrors before:
1553
1554 00.0 0e3 0100j 07.5 00000000000000000008.
1555
Tim Petersbdee63f2001-09-02 03:40:59 +00001556- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001557 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1558
Tim Petersedc99312001-08-22 21:36:50 +00001559Library
1560
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001561- telnetlib includes symbolic names for the options, and support for
1562 setting an option negotiation callback.
1563
Tim Petersa40c7932001-09-05 22:36:56 +00001564- The new C standard no longer requires that math libraries set errno to
1565 ERANGE on overflow. For platform libraries that exploit this new
1566 freedom, Python's overflow-checking was wholly broken. A new overflow-
1567 checking scheme attempts to repair that, but may not be reliable on all
1568 platforms (C doesn't seem to provide anything both useful and portable
1569 in this area anymore).
1570
Martin v. Löwis44f86962001-09-05 13:44:54 +00001571- Asynchronous timeout actions are available through the new class
1572 threading.Timer.
1573
Tim Peters78526162001-09-05 00:53:45 +00001574- math.log and math.log10 now return sensible results for even huge
1575 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1576
Tim Petersbdee63f2001-09-02 03:40:59 +00001577- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001578 currently held. See the docs for the imp module.
1579
Tim Petersbdee63f2001-09-02 03:40:59 +00001580- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001581 dumps containing ints written on platforms where Python ints are 8 bytes.
1582 When read on a box where Python ints are 4 bytes, such values are
1583 converted to Python longs.
1584
Tim Petersbdee63f2001-09-02 03:40:59 +00001585- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001586 code objects is no longer allowed. This plugs a security hole.
1587
Steve Purcell6091cd62001-09-06 16:05:17 +00001588- unittest.TestResult instances no longer store references to tracebacks
1589 generated by test failures. This prevents unexpected dangling references
1590 to objects that should be garbage collected between tests.
1591
Tim Petersedc99312001-08-22 21:36:50 +00001592Tools
1593
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001594- Tools/scripts/fixdiv.py has been added which can be used to fix
1595 division operators as per PEP 238.
1596
Tim Petersedc99312001-08-22 21:36:50 +00001597Build
1598
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001599- If you are an adventurous person using Mac OS X you may want to look at
1600 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1601 application, which can be used for experimenting with Carbon or Cocoa.
1602 Discussion of this on pythonmac-sig, please.
1603
Tim Peters7eea37e2001-09-04 22:08:56 +00001604C API
1605
1606- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001607
Tim Peters9fffa3e2001-09-04 05:14:19 +00001608- Note that PyLong_AsDouble can fail! This has always been true, but no
1609 callers checked for it. It's more likely to fail now, because overflow
1610 errors are properly detected now. The proper way to check:
1611
1612 double x = PyLong_AsDouble(some_long_object);
1613 if (x == -1.0 && PyErr_Occurred()) {
1614 /* The conversion failed. */
1615 }
1616
Tim Petersbdee63f2001-09-02 03:40:59 +00001617- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001618 compile but will not participate in GC. To upgrade an extension
1619 module:
1620
1621 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001622
Neil Schemenauer4042c692001-08-30 15:38:01 +00001623 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1624 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001625
Neil Schemenauer4042c692001-08-30 15:38:01 +00001626 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1627 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001628
Neil Schemenauer4042c692001-08-30 15:38:01 +00001629 - remove PyGC_HEAD_SIZE from object size calculations
1630
1631 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1632
Tim Petersbdee63f2001-09-02 03:40:59 +00001633- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001634 These can be used safely to construct string objects from a
1635 sprintf-style format string (similar to the format string supported
1636 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001637
Tim Petersedc99312001-08-22 21:36:50 +00001638New platforms
1639
Tim Petersb7da0902001-09-02 23:01:43 +00001640- Stephen Hansen contributed patches sufficient to get a clean compile
1641 under Borland C (Windows), but he reports problems running it and ran
1642 out of time to complete the port. Volunteers? Expect a MemoryError
1643 when importing the types module; this is probably shallow, and
1644 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001645
Tim Petersedc99312001-08-22 21:36:50 +00001646Tests
1647
1648Windows
1649
Tim Peters6e13a562001-09-06 00:32:15 +00001650- Large file support is now enabled on Win32 platforms as well as on
1651 Win64. This means that, for example, you can use f.tell() and f.seek()
1652 to manipulate files larger than 2 gigabytes (provided you have enough
1653 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001654 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1655 filesize limit, and large file support makes no difference there.
1656 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1657 NTFS has no practical limit on file size, and files of any size can be
1658 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001659
Tim Petersbdee63f2001-09-02 03:40:59 +00001660- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001661 points to command.com (patch from Brian Quinlan).
1662
Tim Petersedc99312001-08-22 21:36:50 +00001663
Tim Peters20f51a72001-07-21 02:31:40 +00001664What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001665Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001666===========================
1667
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001668Build
1669
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001670- Tim Peters developed a brand new Windows installer using Wise 8.1,
1671 generously donated to us by Wise Solutions.
1672
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001673- configure supports a new option --enable-unicode, with the values
1674 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1675 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001676
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001677- A new configure option --enable-framework builds a Mac OS X framework,
1678 which "make frameworkinstall" will install. This provides a starting
1679 point for more mac-like functionality, join pythonmac-sig@python.org
1680 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001681
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001682- The NeXT platform is no longer supported.
1683
1684- The `new' module is now statically linked.
1685
Tim Peters0afb6092001-08-15 06:06:44 +00001686Tools
1687
1688- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001689 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001690 the module docstring for details.
1691
Tim Peters20f51a72001-07-21 02:31:40 +00001692Tests
1693
Tim Peters5e824c32001-08-12 22:25:01 +00001694- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001695 platforms, allowing to give clearer test result output. regrtest
1696 also has optional --use/-u switch to run normally disabled tests
1697 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001698
Tim Peters20f51a72001-07-21 02:31:40 +00001699- Several new tests in the standard test suite, with special thanks to
1700 Nick Mathewson.
1701
1702Core
1703
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001704- The floor division operator // has been added as outlined in PEP
1705 238. The / operator still provides classic division (and will until
1706 Python 3.0) unless "from __future__ import division" is included, in
1707 which case the / operator will provide true division. The operator
1708 module provides truediv() and floordiv() functions. Augmented
1709 assignment variants are included, as are the equivalent overloadable
1710 methods and C API methods. See the PEP for a full discussion:
1711 <http://python.sf.net/peps/pep-0238.html>
1712
Tim Peters6cd6a822001-08-17 22:11:27 +00001713- Future statements are now effective in simulated interactive shells
1714 (like IDLE). This should "just work" by magic, but read Michael
1715 Hudson's "Future statements in simulated shells" PEP 264 for full
1716 details: <http://python.sf.net/peps/pep-0264.html>.
1717
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001718- The type/class unification (PEP 252-253) was integrated into the
1719 trunk and is not so tentative any more (the exact specification of
1720 some features is still tentative). A lot of work has done on fixing
1721 bugs and adding robustness and features (performance still has to
1722 come a long way).
1723
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001724- Warnings about a mismatch in the Python API during extension import
1725 now use the Python warning framework (which makes it possible to
1726 write filters for these warnings).
1727
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001728- A function's __dict__ (aka func_dict) will now always be a
1729 dictionary. It used to be possible to delete it or set it to None,
1730 but now both actions raise TypeErrors. It is still legal to set it
1731 to a dictionary object. Getting func.__dict__ before any attributes
1732 have been assigned now returns an empty dictionary instead of None.
1733
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001734- A new command line option, -E, was added which disables the use of
1735 all environment variables, or at least those that are specifically
1736 significant to Python. Usually those have a name starting with
1737 "PYTHON". This was used to fix a problem where the tests fail if
1738 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1739 older distribution.
1740
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001741Library
1742
Tim Peters5e824c32001-08-12 22:25:01 +00001743- New class Differ and new functions ndiff() and restore() in difflib.py.
1744 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001745 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001746
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001747- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1748 value using the minimal quoting required for the value; more
1749 reliable than using xml.sax.saxutils.escape() for attribute values.
1750
1751- Readline completion support for cmd.Cmd was added.
1752
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001753- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1754
1755- Added function threading.BoundedSemaphore()
1756
1757- Added Ka-Ping Yee's cgitb.py module.
1758
1759- The `new' module now exposes the CO_xxx flags.
1760
Martin v. Löwis560da622001-11-24 09:24:51 +00001761- The gc module offers the get_referents function.
1762
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001763New platforms
1764
1765C API
1766
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001767- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1768 which provide a cross-platform implementations for the
1769 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1770 the standard sprintf() and vsprintf() C lib APIs, these versions
1771 apply bounds checking on the used buffer which enhances protection
1772 against buffer overruns.
1773
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001774- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001775 and extensions using different Unicode widths is rendered next to
1776 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001777 will result in an ImportError. Unicode extensions writers must make
1778 sure to check the Unicode width compatibility in their extensions by
1779 using at least one of the mangled Unicode APIs in the extension.
1780
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001781- Two new flags METH_NOARGS and METH_O are available in method definition
1782 tables to simplify implementation of methods with no arguments and a
1783 single untyped argument. Calling such methods is more efficient than
1784 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1785 deprecated.
1786
Tim Petersc1731372001-08-04 08:12:36 +00001787Windows
1788
1789- "import module" now compiles module.pyw if it exists and nothing else
1790 relevant is found.
1791
Tim Peters20f51a72001-07-21 02:31:40 +00001792
Guido van Rossum55a78992001-07-17 17:22:32 +00001793What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001794Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001795===========================
1796
1797Core
Tim Petersa814db52001-05-14 07:05:58 +00001798
Tim Peters6d6c1a32001-08-02 04:15:00 +00001799- TENTATIVELY, a large amount of code implementing much of what's
1800 described in PEP 252 (Making Types Look More Like Classes) and PEP
1801 253 (Subtyping Built-in Types) was added. This will be released
1802 with Python 2.2a1. Documentation will be provided separately
1803 through http://www.python.org/2.2/. The purpose of releasing this
1804 with Python 2.2a1 is to test backwards compatibility. It is
1805 possible, though not likely, that a decision is made not to release
1806 this code as part of 2.2 final, if any serious backwards
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00001807 incompatibilities are found during alpha testing that cannot be
Tim Peters6d6c1a32001-08-02 04:15:00 +00001808 repaired.
1809
Guido van Rossum55a78992001-07-17 17:22:32 +00001810- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001811 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001812 more 'yield' statements. See PEP 255. Since this adds a new
1813 keyword to the language, this feature must be enabled by including a
1814 future statement: "from __future__ import generators" (see PEP 236).
1815 Generators will become a standard feature in a future release
1816 (probably 2.3). Without this future statement, 'yield' remains an
1817 ordinary identifier, but a warning is issued each time it is used.
1818 (These warnings currently don't conform to the warnings framework of
1819 PEP 230; we intend to fix this in 2.2a2.)
1820
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001821- The UTF-16 codec was modified to be more RFC compliant. It will now
1822 only remove BOM characters at the start of the string and then
1823 only if running in native mode (UTF-16-LE and -BE won't remove a
1824 leading BMO character).
1825
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001826- Strings now have a new method .decode() to complement the already
1827 existing .encode() method. These two methods provide direct access
1828 to the corresponding decoders and encoders of the registered codecs.
1829
1830 To enhance the usability of the .encode() method, the special
1831 casing of Unicode object return values was dropped (Unicode objects
1832 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001833
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001834 Both methods will now return whatever the codec in charge of the
1835 requested encoding returns as object, e.g. Unicode codecs will
1836 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1837 will return u"äöü"). This enables codec writer to create codecs
1838 for various simple to use conversions.
1839
1840 New codecs were added to demonstrate these new features (the .encode()
1841 and .decode() columns indicate the type of the returned objects):
1842
1843 Name | .encode() | .decode() | Description
1844 ----------------------------------------------------------------------
1845 uu | string | string | UU codec (e.g. for email)
1846 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001847 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001848 zlib | string | string | zlib compression
1849 hex | string | string | 2-byte hex codec
1850 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1851
Mark Hammond2a0af792001-05-14 03:09:36 +00001852- Some operating systems now support the concept of a default Unicode
1853 encoding for file system operations. Notably, Windows supports 'mbcs'
1854 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001855 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001856 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001857
1858 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001859 functions that return filenames (such as os.listdir()) to return Python
1860 string objects pre-encoded using the default file system encoding for
1861 the platform. As this encoding is likely to be different from Python's
1862 default encoding, converting this name to a Unicode object before passing
1863 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001864 would attempt to use its default encoding (generally ASCII) rather than
1865 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001866
Tim Petersa814db52001-05-14 07:05:58 +00001867 In general, this change simply removes surprises when working with
1868 Unicode and the file system, making these operations work as you expect,
1869 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001870 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001871
Tim Peters61dff2b2001-05-08 15:43:37 +00001872- Float (and complex) literals in source code were evaluated to full
1873 precision only when running from a .py file; the same code loaded from a
1874 .pyc (or .pyo) file could suffer numeric differences starting at about the
1875 12th significant decimal digit. For example, on a machine with IEEE-754
1876 floating arithmetic,
1877
1878 x = 9007199254740992.0
1879 print long(x)
1880
1881 printed 9007199254740992 if run directly from .py, but 9007199254740000
1882 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1883 str(float) instead of repr(float) when building code objects. marshal
1884 now uses repr(float) instead, which should reproduce floats to full
1885 machine precision (assuming the platform C float<->string I/O conversion
1886 functions are of good quality).
1887
1888 This may cause floating-point results to change in some cases, and
1889 usually for the better, but may also cause numerically unstable
1890 algorithms to break.
1891
Tim Peters2f228e72001-05-13 00:19:31 +00001892- The implementation of dicts suffers fewer collisions, which has speed
1893 benefits. However, the order in which dict entries appear in dict.keys(),
1894 dict.values() and dict.items() may differ from previous releases for a
1895 given dict. Nothing is defined about this order, so no program should
1896 rely on it. Nevertheless, it's easy to write test cases that rely on the
1897 order by accident, typically because of printing the str() or repr() of a
1898 dict to an "expected results" file. See Lib/test/test_support.py's new
1899 sortdict(dict) function for a simple way to display a dict in sorted
1900 order.
1901
Tim Peters7a3bfc32001-06-12 01:22:22 +00001902- Many other small changes to dicts were made, resulting in faster
1903 operation along the most common code paths.
1904
Guido van Rossum10315822001-05-01 20:54:30 +00001905- Dictionary objects now support the "in" operator: "x in dict" means
1906 the same as dict.has_key(x).
1907
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001908- The update() method of dictionaries now accepts generic mapping
1909 objects. Specifically the argument object must support the .keys()
1910 and __getitem__() methods. This allows you to say, for example,
1911 {}.update(UserDict())
1912
Guido van Rossum10315822001-05-01 20:54:30 +00001913- Iterators were added; this is a generalized way of providing values
1914 to a for loop. See PEP 234. There's a new built-in function iter()
1915 to return an iterator. There's a new protocol to get the next value
1916 from an iterator using the next() method (in Python) or the
1917 tp_iternext slot (in C). There's a new protocol to get iterators
1918 using the __iter__() method (in Python) or the tp_iter slot (in C).
1919 Iterating (i.e. a for loop) over a dictionary generates its keys.
1920 Iterating over a file generates its lines.
1921
Tim Petersf553f892001-05-01 20:45:31 +00001922- The following functions were generalized to work nicely with iterator
1923 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001924 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001925 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1926 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001927 join() method of strings
1928 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001929 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1930 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001931 right-hand side of assignment statements with multiple targets, such as
1932 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001933
Tim Petersd85e1022001-05-11 21:51:48 +00001934- Accessing module attributes is significantly faster (for example,
1935 random.random or os.path or yourPythonModule.yourAttribute).
1936
Tim Peterse63415e2001-05-08 04:38:29 +00001937- Comparing dictionary objects via == and != is faster, and now works even
1938 if the keys and values don't support comparisons other than ==.
1939
Tim Peters95bf9392001-05-10 08:32:44 +00001940- Comparing dictionaries in ways other than == and != is slower: there were
1941 insecurities in the dict comparison implementation that could cause Python
1942 to crash if the element comparison routines for the dict keys and/or
1943 values mutated the dicts. Making the code bulletproof slowed it down.
1944
Tim Peterseb28ef22001-06-02 05:27:19 +00001945- Collisions in dicts are resolved via a new approach, which can help
1946 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001947 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001948 faster now. Thanks to Christian Tismer for pointing out the cause and
1949 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001950
Tim Peters52e155e2001-06-16 05:42:57 +00001951- repr() is much faster for large containers (dict, list, tuple).
1952
1953
Tim Petersa814db52001-05-14 07:05:58 +00001954Library
1955
Fred Drake960fdf92001-07-20 18:38:26 +00001956- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00001957 were added to the string module. These a locale-independent
Fred Drake960fdf92001-07-20 18:38:26 +00001958 constants, unlike letters, lowercase, and uppercase. These are now
1959 use in appropriate locations in the standard library.
1960
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001961- The flags used in dlopen calls can now be configured using
1962 sys.setdlopenflags and queried using sys.getdlopenflags.
1963
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001964- Fredrik Lundh's xmlrpclib is now a standard library module. This
1965 provides full client-side XML-RPC support. In addition,
1966 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1967 one asyncore-based). Thanks to Eric Raymond for the documentation.
1968
Guido van Rossum643d3912001-07-05 14:46:25 +00001969- The xrange() object is simplified: it no longer supports slicing,
1970 repetition, comparisons, efficient 'in' checking, the tolist()
1971 method, or the start, stop and step attributes. See PEP 260.
1972
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001973- A new function fnmatch.filter to filter lists of file names was added.
1974
Barry Warsawffd674d2001-05-22 16:00:10 +00001975- calendar.py uses month and day names based on the current locale.
1976
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001977- strop is now *really* obsolete (this was announced before with 1.6),
1978 and issues DeprecationWarning when used (except for the four items
1979 that are still imported into string.py).
1980
Tim Petersa814db52001-05-14 07:05:58 +00001981- Cookie.py now sorts key+value pairs by key in output strings.
1982
1983- pprint.isrecursive(object) didn't correctly identify recursive objects.
1984 Now it does.
1985
Tim Peters95b3f782001-05-14 18:39:41 +00001986- pprint functions now much faster for large containers (tuple, list, dict).
1987
Tim Peters7b9542a2001-06-10 23:40:19 +00001988- New 'q' and 'Q' format codes in the struct module, corresponding to C
1989 types "long long" and "unsigned long long" (on Windows, __int64). In
1990 native mode, these can be used only when the platform C compiler supports
1991 these types (when HAVE_LONG_LONG is #define'd by the Python config
1992 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001993 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1994 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001995
Guido van Rossum83213cc2001-06-12 16:48:52 +00001996- The site module installs a new built-in function 'help' that invokes
1997 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1998 it displays a message reminding the user to use 'help()' or
1999 'help(object)'.
2000
Tim Petersa814db52001-05-14 07:05:58 +00002001Tests
2002
2003- New test_mutants.py runs dict comparisons where the key and value
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002004 comparison operators mutate the dicts randomly during comparison. This
Tim Petersa814db52001-05-14 07:05:58 +00002005 rapidly causes Python to crash under earlier releases (not for the faint
2006 of heart: it can also cause Win9x to freeze or reboot!).
2007
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002008- New test_pprint.py verifies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00002009 pprint.isreadable() return sensible results. Also verifies that simple
2010 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00002011
Tim Peters4324aa32001-05-28 22:30:08 +00002012C API
2013
2014- Removed the unused last_is_sticky argument from the internal
2015 _PyTuple_Resize(). If this affects you, you were cheating.
2016
2017
Guido van Rossum55a78992001-07-17 17:22:32 +00002018======================================================================
2019
2020
Guido van Rossumffe13be2001-04-16 18:46:45 +00002021What's New in Python 2.1 (final)?
2022=================================
2023
2024We only changed a few things since the last release candidate, all in
2025Python library code:
2026
2027- A bug in the locale module was fixed that affected locales which
2028 define no grouping for numeric formatting.
2029
2030- A few bugs in the weakref module's implementations of weak
2031 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
2032 and the test suite was updated to check for these bugs.
2033
2034- An old bug in the os.path.walk() function (introduced in Python
2035 2.0!) was fixed: a non-existent file would cause an exception
2036 instead of being ignored.
2037
2038- Fixed a few bugs in the new symtable module found by Neil Norwitz's
2039 PyChecker.
2040
2041
Guido van Rossum5b08f132001-04-16 02:05:23 +00002042What's New in Python 2.1c2?
2043===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00002044
Guido van Rossum5b08f132001-04-16 02:05:23 +00002045A flurry of small changes, and one showstopper fixed in the nick of
2046time made it necessary to release another release candidate. The list
2047here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00002048
Guido van Rossum5b08f132001-04-16 02:05:23 +00002049Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00002050
Guido van Rossum5b08f132001-04-16 02:05:23 +00002051- Tim discovered a nasty bug in the dictionary code, caused by
2052 PyDict_Next() calling dict_resize(), and the GC code's use of
2053 PyDict_Next() violating an assumption in dict_items(). This was
2054 fixed with considerable amounts of band-aid, but the net effect is a
2055 saner and more robust implementation.
2056
2057- Made a bunch of symbols static that were accidentally global.
2058
2059Build and Ports
2060
2061- The setup.py script didn't check for a new enough version of zlib
2062 (1.1.3 is needed). Now it does.
2063
2064- Changed "make clean" target to also remove shared libraries.
2065
2066- Added a more general warning about the SGI Irix optimizer to README.
2067
2068Library
2069
2070- Fix a bug in urllib.basejoin("http://host", "../file.html") which
2071 omitted the slash between host and file.html.
2072
2073- The mailbox module's _Mailbox class contained a completely broken
2074 and undocumented seek() method. Ripped it out.
2075
2076- Fixed a bunch of typos in various library modules (urllib2, smtpd,
2077 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
2078
2079- Fixed a few last-minute bugs in unittest.
2080
2081Extensions
2082
2083- Reverted the patch to the OpenSSL code in socketmodule.c to support
2084 RAND_status() and the EGD, and the subsequent patch that tried to
2085 fix it for pre-0.9.5 versions; the problem with the patch is that on
2086 some systems it issues a warning whenever socket is imported, and
2087 that's unacceptable.
2088
2089Tests
2090
2091- Fixed the pickle tests to work with "import test.test_pickle".
2092
2093- Tweaked test_locale.py to actually run the test Windows.
2094
2095- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
2096 not "wb" (which is not a valid mode at all).
2097
2098- Fix pstats browser crashes. Import readline if it exists to make
2099 the user interface nicer.
2100
2101- Add "import thread" to the top of test modules that import the
2102 threading module (test_asynchat and test_threadedtempfile). This
2103 prevents test failures caused by a broken threading module resulting
2104 from a previously caught failed import.
2105
2106- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
2107 needed on some platforms (e.g. Solaris 8) when the tests are run
2108 twice in succession.
2109
2110- Skip rather than fail test_sunaudiodev if no audio device is found.
2111
2112
2113What's New in Python 2.1c1?
2114===========================
2115
2116This list was significantly updated when 2.1c2 was released; the 2.1c1
2117release didn't mention most changes that were actually part of 2.1c1:
2118
2119Legal
2120
2121- Copyright was assigned to the Python Software Foundation (PSF) and a
2122 PSF license (very similar to the CNRI license) was added.
2123
2124- The CNRI copyright notice was updated to include 2001.
2125
2126Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00002127
Guido van Rossumc9932722001-04-12 02:31:27 +00002128- After a public outcry, assignment to __debug__ is no longer illegal;
2129 instead, a warning is issued. It will become illegal in 2.2.
2130
Guido van Rossum5b08f132001-04-16 02:05:23 +00002131- Fixed a core dump with "%#x" % 0, and changed the semantics so that
2132 "%#x" now always prepends "0x", even if the value is zero.
2133
2134- Fixed some nits in the bytecode compiler.
2135
2136- Fixed core dumps when calling certain kinds of non-functions.
2137
2138- Fixed various core dumps caused by reference count bugs.
2139
2140Build and Ports
2141
2142- Use INSTALL_SCRIPT to install script files.
2143
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002144- New port: SCO Unixware 7, by Billy G. Allie.
2145
Guido van Rossum5b08f132001-04-16 02:05:23 +00002146- Updated RISCOS port.
2147
2148- Updated BeOS port and notes.
2149
2150- Various other porting problems resolved.
2151
2152Library
2153
2154- The TERMIOS and SOCKET modules are now truly obsolete and
2155 unnecessary. Their symbols are incorporated in the termios and
2156 socket modules.
2157
2158- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
2159 better tests for pickling.
2160
2161- threading: make Condition.wait() robust against KeyboardInterrupt.
2162
2163- zipfile: add support to zipfile to support opening an archive
2164 represented by an open file rather than a file name. Fix bug where
2165 the archive was not properly closed. Fixed a bug in this bugfix
2166 where flush() was called for a read-only file.
2167
2168- imputil: added an uninstall() method to the ImportManager.
2169
2170- Canvas: fixed bugs in lower() and tkraise() methods.
2171
2172- SocketServer: API change (added overridable close_request() method)
2173 so that the TCP server can explicitly close the request.
2174
2175- pstats: Eric Raymond added a simple interactive statistics browser,
2176 invoked when the module is run as a script.
2177
2178- locale: fixed a problem in format().
2179
2180- webbrowser: made it work when the BROWSER environment variable has a
2181 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
2182 KDE 2. Fixed some other nits.
2183
2184- unittest: changes to allow using a different exception than
2185 AssertionError, and added a few more function aliases. Some other
2186 small changes.
2187
2188- urllib, urllib2: fixed redirect problems and a coupleof other nits.
2189
2190- asynchat: fixed a critical bug in asynchat that slipped through the
2191 2.1b2 release. Fixed another rare bug.
2192
2193- Fix some unqualified except: clauses (always a bad code example).
2194
2195XML
2196
2197- pyexpat: new API get_version_string().
2198
2199- Fixed some minidom bugs.
2200
2201Extensions
2202
2203- Fixed a core dump in _weakref. Removed the weakref.mapping()
2204 function (it adds nothing to the API).
2205
2206- Rationalized the use of header files in the readline module, to make
2207 it compile (albeit with some warnings) with the very recent readline
2208 4.2, without breaking for earlier versions.
2209
2210- Hopefully fixed a buffering problem in linuxaudiodev.
2211
2212- Attempted a fix to make the OpenSSL support in the socket module
2213 work again with pre-0.9.5 versions of OpenSSL.
2214
2215Tests
2216
2217- Added a test case for asynchat and asyncore.
2218
2219- Removed coupling between tests where one test failing could break
2220 another.
2221
2222Tools
2223
2224- Ping added an interactive help browser to pydoc, fixed some nits
2225 in the rest of the pydoc code, and added some features to his
2226 inspect module.
2227
2228- An updated python-mode.el version 4.1 which integrates Ken
2229 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
2230 much nicer in XEmacs and Emacs. When stepping through your program
2231 with pdb, in either the shell window or the *Python* window, the
2232 source file and line will be tracked by an arrow. Very cool!
2233
2234- IDLE: syntax warnings in interactive mode are changed into errors.
2235
2236- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00002237 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00002238
2239- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002240
Barry Warsaw11e89c72001-04-11 20:37:57 +00002241
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002242What's New in Python 2.1 beta 2?
2243================================
2244
Guido van Rossum053ae352001-03-22 14:17:21 +00002245(Unlisted are many fixed bugs, more documentation, etc.)
2246
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002247Core language, builtins, and interpreter
2248
Guido van Rossum053ae352001-03-22 14:17:21 +00002249- The nested scopes work (enabled by "from __future__ import
2250 nested_scopes") is completed; in particular, the future now extends
2251 into code executed through exec, eval() and execfile(), and into the
2252 interactive interpreter.
2253
2254- When calling a base class method (e.g. BaseClass.__init__(self)),
2255 this is now allowed even if self is not strictly spoken a class
2256 instance (e.g. when using metaclasses or the Don Beaudry hook).
2257
2258- Slice objects are now comparable but not hashable; this prevents
2259 dict[:] from being accepted but meaningless.
2260
2261- Complex division is now calculated using less braindead algorithms.
2262 This doesn't change semantics except it's more likely to give useful
2263 results in extreme cases. Complex repr() now uses full precision
2264 like float repr().
2265
2266- sgmllib.py now calls handle_decl() for simple <!...> declarations.
2267
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002268- It is illegal to assign to the name __debug__, which is set when the
2269 interpreter starts. It is effectively a compile-time constant.
2270
2271- A warning will be issued if a global statement for a variable
2272 follows a use or assignment of that variable.
2273
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002274Standard library
2275
Guido van Rossum053ae352001-03-22 14:17:21 +00002276- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
2277 inspired by JUnit), is now part of the standard library. You now
2278 have a choice of two testing frameworks: unittest requires you to
2279 write testcases as separate code, doctest gathers them from
2280 docstrings. Both approaches have their advantages and
2281 disadvantages.
2282
2283- A new module Tix was added, which wraps the Tix extension library
2284 for Tk. With that module, it is not necessary to statically link
2285 Tix with _tkinter, since Tix will be loaded with Tcl's "package
2286 require" command. See Demo/tix/.
2287
2288- tzparse.py is now obsolete.
2289
2290- In gzip.py, the seek() and tell() methods are removed -- they were
2291 non-functional anyway, and it's better if callers can test for their
2292 existence with hasattr().
2293
2294Python/C API
2295
2296- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
2297 that's already in the dictionary during a PyDict_Next() iteration.
2298 This used to fail occasionally when a dictionary resize operation
2299 could be triggered that would rehash all the keys. All other
2300 modifications to the dictionary are still off-limits during a
2301 PyDict_Next() iteration!
2302
2303- New extended APIs related to passing compiler variables around.
2304
2305- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
2306 implement isinstance() and issubclass().
2307
2308- Py_BuildValue() now has a "D" conversion to create a Python complex
2309 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002310
Fred Drake4e262a92001-03-22 18:26:47 +00002311- Extensions types which support weak references must now set the
2312 field allocated for the weak reference machinery to NULL themselves;
2313 this is done to avoid the cost of checking each object for having a
2314 weakly referencable type in PyObject_INIT(), since most types are
2315 not weakly referencable.
2316
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002317- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
2318 free variables and cell variables to and from the frame's f_locals.
2319
2320- Variants of several functions defined in pythonrun.h have been added
2321 to support the nested_scopes future statement. The variants all end
2322 in Flags and take an extra argument, a PyCompilerFlags *; examples:
2323 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
2324 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00002325 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002326
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002327Distutils
2328
2329- the sdist command now writes a PKG-INFO file, as described in PEP 241,
2330 into the release tree.
2331
Tim Peters0e57abf2001-05-02 07:39:38 +00002332- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002333 (an uninstaller, more customization of the installer's display)
2334
2335- from Jack Jansen: added Mac-specific code to generate a dialog for
2336 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00002337 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002338 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00002339
2340- added 'platforms' and 'keywords' to the set of metadata that can be
2341 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002342
2343- applied patches from Jason Tishler to make the compiler class work with
2344 Cygwin.
2345
2346
Tim Peters2fe289a2001-03-01 22:19:38 +00002347What's New in Python 2.1 beta 1?
2348================================
Tim Petersd66595f2001-02-04 03:09:53 +00002349
2350Core language, builtins, and interpreter
2351
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00002352- Following an outcry from the community about the amount of code
2353 broken by the nested scopes feature introduced in 2.1a2, we decided
2354 to make this feature optional, and to wait until Python 2.2 (or at
2355 least 6 months) to make it standard. The option can be enabled on a
2356 per-module basis by adding "from __future__ import nested_scopes" at
2357 the beginning of a module (before any other statements, but after
2358 comments and an optional docstring). See PEP 236 (Back to the
2359 __future__) for a description of the __future__ statement. PEP 227
2360 (Statically Nested Scopes) has been updated to reflect this change,
2361 and to clarify the semantics in a number of endcases.
2362
2363- The nested scopes code, when enabled, has been hardened, and most
2364 bugs and memory leaks in it have been fixed.
2365
2366- Compile-time warnings are now generated for a number of conditions
2367 that will break or change in meaning when nested scopes are enabled:
2368
2369 - Using "from...import *" or "exec" without in-clause in a function
2370 scope that also defines a lambda or nested function with one or
2371 more free (non-local) variables. The presence of the import* or
2372 bare exec makes it impossible for the compiler to determine the
2373 exact set of local variables in the outer scope, which makes it
2374 impossible to determine the bindings for free variables in the
2375 inner scope. To avoid the warning about import *, change it into
2376 an import of explicitly name object, or move the import* statement
2377 to the global scope; to avoid the warning about bare exec, use
2378 exec...in... (a good idea anyway -- there's a possibility that
2379 bare exec will be deprecated in the future).
2380
2381 - Use of a global variable in a nested scope with the same name as a
2382 local variable in a surrounding scope. This will change in
2383 meaning with nested scopes: the name in the inner scope will
2384 reference the variable in the outer scope rather than the global
2385 of the same name. To avoid the warning, either rename the outer
2386 variable, or use a global statement in the inner function.
2387
Neil Schemenauera35c6882001-02-27 04:45:05 +00002388- An optional object allocator has been included. This allocator is
2389 optimized for Python objects and should be faster and use less memory
2390 than the standard system allocator. It is not enabled by default
2391 because of possible thread safety problems. The allocator is only
2392 protected by the Python interpreter lock and it is possible that some
2393 extension modules require a thread safe allocator. The object
2394 allocator can be enabled by providing the "--with-pymalloc" option to
2395 configure.
2396
Tim Petersd66595f2001-02-04 03:09:53 +00002397Standard library
2398
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002399- pyexpat now detects the expat version if expat.h defines it. A
2400 number of additional handlers are provided, which are only available
2401 since expat 1.95. In addition, the methods SetParamEntityParsing and
2402 GetInputContext of Parser objects are available with 1.95.x
2403 only. Parser objects now provide the ordered_attributes and
2404 specified_attributes attributes. A new module expat.model was added,
2405 which offers a number of additional constants if 1.95.x is used.
2406
2407- xml.dom offers the new functions registerDOMImplementation and
2408 getDOMImplementation.
2409
2410- xml.dom.minidom offers a toprettyxml method. A number of DOM
2411 conformance issues have been resolved. In particular, Element now
2412 has an hasAttributes method, and the handling of namespaces was
2413 improved.
2414
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002415- Ka-Ping Yee contributed two new modules: inspect.py, a module for
2416 getting information about live Python code, and pydoc.py, a module
2417 for interactively converting docstrings to HTML or text.
2418 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002419 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002420 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2421 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002422
Tim Peters1eff7962001-03-01 02:31:33 +00002423- New library module difflib.py, primarily packaging the SequenceMatcher
2424 class at the heart of the popular ndiff.py file-comparison tool.
2425
2426- doctest.py (a framework for verifying Python code examples in docstrings)
2427 is now part of the std library.
2428
Tim Petersd66595f2001-02-04 03:09:53 +00002429Windows changes
2430
Guido van Rossume3955a82001-03-02 14:05:59 +00002431- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2432 small GUI that lets you browse the module docstrings using your
2433 default web browser.
2434
Tim Peters1eff7962001-03-01 02:31:33 +00002435- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2436 Platforms) is implemented. See
2437
2438 http://python.sourceforge.net/peps/pep-0235.html
2439
2440 for full details, especially the "Current Lower-Left Semantics" section.
2441 The new Windows import rules are simpler than before:
2442
2443 A. If the PYTHONCASEOK environment variable exists, same as
2444 before: silently accept the first case-insensitive match of any
2445 kind; raise ImportError if none found.
2446
2447 B. Else search sys.path for the first case-sensitive match; raise
2448 ImportError if none found.
2449
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002450 The same rules have been implemented on other platforms with case-
Tim Peters1eff7962001-03-01 02:31:33 +00002451 insensitive but case-preserving filesystems too (including Cygwin, and
2452 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002453
Tim Peters25a9ce32001-02-19 07:06:36 +00002454- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2455 what it's supposed to do (and does do under NT and 2000) via direct
2456 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002457 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002458 all Win9x systems before.
2459
Tim Peters1eff7962001-03-01 02:31:33 +00002460- Build: Subproject _test (effectively) renamed to _testcapi.
2461
Tim Peters2fe289a2001-03-01 22:19:38 +00002462New platforms
2463
2464- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2465 Thanks to Steven Majewski!
2466
2467- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2468 Tishler!
2469
Guido van Rossum9089b272001-03-02 06:49:50 +00002470- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2471 Schwertberger! See RISCOS/README for more information -- it seems
2472 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002473 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002474
Tim Peters25a9ce32001-02-19 07:06:36 +00002475
Tim Petersd7b5e882001-01-25 03:36:26 +00002476What's New in Python 2.1 alpha 2?
2477=================================
Tim Peters40ead762001-01-27 05:35:26 +00002478
Tim Petersd7b5e882001-01-25 03:36:26 +00002479Core language, builtins, and interpreter
2480
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002481- Scopes nest. If a name is used in a function or class, but is not
2482 local, the definition in the nearest enclosing function scope will
2483 be used. One consequence of this change is that lambda statements
2484 could reference variables in the namespaces where the lambda is
2485 defined. In some unusual cases, this change will break code.
2486
2487 In all previous version of Python, names were resolved in exactly
2488 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002489 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002490 function A is defined within a function B, the names bound in B are
2491 not visible in A. The new rules make names bound in B visible in A,
2492 unless A contains a name binding that hides the binding in B.
2493
2494 Section 4.1 of the reference manual describes the new scoping rules
2495 in detail. The test script in Lib/test/test_scope.py demonstrates
2496 some of the effects of the change.
2497
2498 The new rules will cause existing code to break if it defines nested
2499 functions where an outer function has local variables with the same
2500 name as globals or builtins used by the inner function. Example:
2501
2502 def munge(str):
2503 def helper(x):
2504 return str(x)
2505 if type(str) != type(''):
2506 str = helper(str)
2507 return str.strip()
2508
2509 Under the old rules, the name str in helper() is bound to the
2510 builtin function str(). Under the new rules, it will be bound to
2511 the argument named str and an error will occur when helper() is
2512 called.
2513
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002514- The compiler will report a SyntaxError if "from ... import *" occurs
2515 in a function or class scope. The language reference has documented
2516 that this case is illegal, but the compiler never checked for it.
2517 The recent introduction of nested scope makes the meaning of this
2518 form of name binding ambiguous. In a future release, the compiler
2519 may allow this form when there is no possibility of ambiguity.
2520
Tim Peters40ead762001-01-27 05:35:26 +00002521- repr(string) is easier to read, now using hex escapes instead of octal,
2522 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2523
2524 >>> "\texample \r\n" + chr(0) + chr(255)
2525 '\texample \r\n\x00\xff' # in 2.1
2526 '\011example \015\012\000\377' # in 2.0
2527
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002528- Functions are now compared and hashed by identity, not by value, since
2529 the func_code attribute is writable.
2530
Fred Drakefb9d7122001-02-01 20:00:40 +00002531- Weak references (PEP 205) have been added. This involves a few
2532 changes in the core, an extension module (_weakref), and a Python
2533 module (weakref). The weakref module is the public interface. It
2534 includes support for "explicit" weak references, proxy objects, and
2535 mappings with weakly held values.
2536
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002537- A 'continue' statement can now appear in a try block within the body
2538 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002539 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002540
Tim Petersd7b5e882001-01-25 03:36:26 +00002541Standard library
2542
Barry Warsaw30dbd142001-01-31 22:14:01 +00002543- mailbox.py now has a new class, PortableUnixMailbox which is
2544 identical to UnixMailbox but uses a more portable scheme for
2545 determining From_ separators. Also, the constructors for all the
2546 classes in this module have a new optional `factory' argument, which
2547 is a callable used when new message classes must be instantiated by
2548 the next() method.
2549
Tim Petersd7b5e882001-01-25 03:36:26 +00002550- random.py is now self-contained, and offers all the functionality of
2551 the now-deprecated whrandom.py. See the docs for details. random.py
2552 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002553 and restoring the internal state of the generator; and jumpahead(n),
2554 for quickly forcing the internal state to be the same as if n calls to
2555 random() had been made. The latter is particularly useful for multi-
2556 threaded programs, creating one instance of the random.Random() class for
2557 each thread, then using .jumpahead() to force each instance to use a
2558 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002559
Tim Peters0de88fc2001-02-01 04:59:18 +00002560- random.py's seed() function is new. For bit-for-bit compatibility with
2561 prior releases, use the whseed function instead. The new seed function
2562 addresses two problems: (1) The old function couldn't produce more than
2563 about 2**24 distinct internal states; the new one about 2**45 (the best
2564 that can be done in the Wichmann-Hill generator). (2) The old function
2565 sometimes produced identical internal states when passed distinct
2566 integers, and there was no simple way to predict when that would happen;
2567 the new one guarantees to produce distinct internal states for all
2568 arguments in [0, 27814431486576L).
2569
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002570- The socket module now supports raw packets on Linux. The socket
2571 family is AF_PACKET.
2572
Tim Peters9ea17ac2001-02-02 05:57:15 +00002573- test_capi.py is a start at running tests of the Python C API. The tests
2574 are implemented by the new Modules/_testmodule.c.
2575
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002576- A new extension module, _symtable, provides provisional access to the
2577 internal symbol table used by the Python compiler. A higher-level
2578 interface will be added on top of _symtable in a future release.
2579
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002580- Removed the obsolete soundex module.
2581
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002582- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2583 the isSameNode method; NamedNodeMap the get method.
2584
2585- xml.sax.expatreader supports the lexical handler property; it
2586 generates comment, startCDATA, and endCDATA events.
2587
Tim Petersee826f82001-01-31 19:39:44 +00002588Windows changes
2589
2590- Build procedure: the zlib project is built in a different way that
2591 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002592 the zlib binary used. See PCbuild\readme.txt for details. Your old
2593 zlib-related directories can be deleted; you'll need to download fresh
2594 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002595
Tim Peters9ea17ac2001-02-02 05:57:15 +00002596- Build: New subproject _test for the benefit of test_capi.py (see above).
2597
Tim Petersb16c56f2001-02-02 21:24:51 +00002598- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2599 interface to some Python compiler internals).
2600
2601- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002602 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002603
Tim Petersa3a3a032000-11-30 05:22:44 +00002604What's New in Python 2.1 alpha 1?
2605=================================
2606
2607Core language, builtins, and interpreter
2608
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002609- There is a new Unicode companion to the PyObject_Str() API
2610 called PyObject_Unicode(). It behaves in the same way as the
2611 former, but assures that the returned value is an Unicode object
2612 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002613
Guido van Rossumf98eda02001-01-17 15:54:45 +00002614- The comparison operators support "rich comparison overloading" (PEP
2615 207). C extension types can provide a rich comparison function in
2616 the new tp_richcompare slot in the type object. The cmp() function
2617 and the C function PyObject_Compare() first try the new rich
2618 comparison operators before trying the old 3-way comparison. There
2619 is also a new C API PyObject_RichCompare() (which also falls back on
2620 the old 3-way comparison, but does not constrain the outcome of the
2621 rich comparison to a Boolean result).
2622
2623 The rich comparison function takes two objects (at least one of
2624 which is guaranteed to have the type that provided the function) and
2625 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2626 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2627 object, which may be NotImplemented (in which case the tp_compare
2628 slot function is used as a fallback, if defined).
2629
2630 Classes can overload individual comparison operators by defining one
2631 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002632 __ge__. There are no explicit "reflected argument" versions of
2633 these; instead, __lt__ and __gt__ are each other's reflection,
2634 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2635 reflection (similar at the C level). No other implications are
2636 made; in particular, Python does not assume that == is the Boolean
2637 inverse of !=, or that < is the Boolean inverse of >=. This makes
2638 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002639
2640 Classes or types that want to implement (in)equality tests but not
2641 the ordering operators (i.e. unordered types) should implement ==
2642 and !=, and raise an error for the ordering operators.
2643
Guido van Rossuma88479f2001-01-18 14:28:08 +00002644 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002645 Boolean; e.g. a matrix type might want to return a matrix of bits
2646 for A < B, giving elementwise comparisons. Such types should ensure
2647 that any interpretation of their value in a Boolean context raises
2648 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2649 at the C level) to always raise an exception.
2650
Guido van Rossuma88479f2001-01-18 14:28:08 +00002651- Complex numbers use rich comparisons to define == and != but raise
2652 an exception for <, <=, > and >=. Unfortunately, this also means
2653 that cmp() of two complex numbers raises an exception when the two
2654 numbers differ. Since it is not mathematically meaningful to compare
2655 complex numbers except for equality, I hope that this doesn't break
2656 too much code.
2657
Tim Peters3389f192001-02-18 08:48:49 +00002658- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002659 not defined by the language, other than that it's arbitrary but
2660 consistent (see the Reference Manual). An implementation detail changed
2661 in 2.1a1 such that None now compares less than any other object. Code
2662 relying on this new behavior (like code that relied on the previous
2663 behavior) does so at its own risk.
2664
Barry Warsaw573b5412001-01-15 20:43:18 +00002665- Functions and methods now support getting and setting arbitrarily
2666 named attributes (PEP 232). Functions have a new __dict__
2667 (a.k.a. func_dict) which hold the function attributes. Methods get
2668 and set attributes on their underlying im_func. It is a TypeError
2669 to set an attribute on a bound method.
2670
Guido van Rossum051e3352001-01-15 19:11:10 +00002671- The xrange() object implementation has been improved so that
2672 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2673 limitation that in this case len(xrange(sys.maxint)) can't be
2674 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2675 work fine as long as the index i doesn't actually reach 2**31.
2676 (Python uses regular ints for sequence and string indices; fixing
2677 that is much more work.)
2678
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002679- Two changes to from...import:
2680
Guido van Rossumba381232001-02-03 15:06:40 +00002681 1) "from M import X" now works even if (after loading module M)
2682 sys.modules['M'] is not a real module; it's basically a getattr()
2683 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002684
2685 2) "from M import *" now looks for M.__all__ to decide which names to
2686 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2687 filters out names starting with '_' as before. Whether or not
2688 __all__ exists, there's no restriction on the type of M.
2689
Guido van Rossumf61f1662001-01-10 20:13:55 +00002690- File objects have a new method, xreadlines(). This is the fastest
2691 way to iterate over all lines in a file:
2692
2693 for line in file.xreadlines():
2694 ...do something to line...
2695
2696 See the xreadlines module (mentioned below) for how to do this for
2697 other file-like objects.
2698
2699- Even if you don't use file.xreadlines(), you may expect a speedup on
2700 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002701 quite a bit in platform-specific ways: on systems (like Linux) that
2702 support flockfile(), getc_unlocked(), and funlockfile(), those are
2703 used by default. On systems (like Windows) without getc_unlocked(),
2704 a complicated (but still thread-safe) method using fgets() is used by
2705 default.
2706
Tim Petersd52269b2001-01-25 06:23:18 +00002707 You can force use of the fgets() method by #define'ing
2708 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002709 getc_unlocked()).
2710
Tim Petersd52269b2001-01-25 06:23:18 +00002711 You can force fgets() not to be used by #define'ing
2712 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002713 test_bufio.py fails -- and let us know if it does!).
2714
2715- In addition, the fileinput module, while still slower than the other
2716 methods on most platforms, has been sped up too, by using
2717 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002718
2719- Support for run-time warnings has been added, including a new
2720 command line option (-W) to specify the disposition of warnings.
2721 See the description of the warnings module below.
2722
2723- Extensive changes have been made to the coercion code. This mostly
2724 affects extension modules (which can now implement mixed-type
2725 numerical operators without having to use coercion), but
2726 occasionally, in boundary cases the coercion semantics have changed
2727 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002728 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002729 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002730 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002731
Guido van Rossumf98eda02001-01-17 15:54:45 +00002732- In connection with the coercion changes, a new built-in singleton
2733 object, NotImplemented is defined. This can be returned for
2734 operations that wish to indicate they are not implemented for a
2735 particular combination of arguments. From C, this is
2736 Py_NotImplemented.
2737
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002738- The interpreter accepts now bytecode files on the command line even
2739 if they do not have a .pyc or .pyo extension. On Linux, after executing
2740
Martin v. Löwise214baa2001-02-04 22:37:56 +00002741import imp,sys,string
2742magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2743reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2744open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002745
2746 any byte code file can be used as an executable (i.e. as an argument
2747 to execve(2)).
2748
Tim Peters9940b802000-12-01 07:59:35 +00002749- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002750 character. In 1.6 and earlier, they never produced a sign,
2751 and raised an error if the value of the long was too large
2752 to fit in a Python int. In 2.0, they produced a sign if and
2753 only if too large to fit in an int. This was inconsistent
2754 across platforms (because the size of an int varies across
2755 platforms), and inconsistent with hex() and oct(). Example:
2756
2757 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002758 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002759 'ffffffbe' # in 2.0 and before, on 32-bit machines
2760 >>> hex(-0x42L)
2761 '-0x42L' # in all versions of Python
2762
Tim Peters9940b802000-12-01 07:59:35 +00002763 The behavior of %d formats for negative Python longs remains
2764 the same as in 2.0 (although in 1.6 and before, they raised
2765 an error if the long didn't fit in a Python int).
2766
2767 %u formats don't make sense for Python longs, but are allowed
2768 and treated the same as %d in 2.1. In 2.0, a negative long
2769 formatted via %u produced a sign if and only if too large to
2770 fit in an int. In 1.6 and earlier, a negative long formatted
2771 via %u raised an error if it was too big to fit in an int.
2772
Guido van Rossum3661d392000-12-12 22:10:31 +00002773- Dictionary objects have an odd new method, popitem(). This removes
2774 an arbitrary item from the dictionary and returns it (in the form of
2775 a (key, value) pair). This can be useful for algorithms that use a
2776 dictionary as a bag of "to do" items and repeatedly need to pick one
2777 item. Such algorithms normally end up running in quadratic time;
2778 using popitem() they can usually be made to run in linear time.
2779
Tim Peters36cdad12000-12-29 02:06:45 +00002780Standard library
2781
Thomas Woutersfe385252001-01-19 23:16:56 +00002782- In the time module, the time argument to the functions strftime,
2783 localtime, gmtime, asctime and ctime is now optional, defaulting to
2784 the current time (in the local timezone).
2785
Guido van Rossumda91f222001-01-15 16:36:08 +00002786- The ftplib module now defaults to passive mode, which is deemed a
2787 more useful default given that clients are often inside firewalls
2788 these days. Note that this could break if ftplib is used to connect
2789 to a *server* that is inside a firewall, from outside; this is
2790 expected to be a very rare situation. To fix that, you can call
2791 ftp.set_pasv(0).
2792
Martin v. Löwis10a27872001-01-13 09:54:41 +00002793- The module site now treats .pth files not only for path configuration,
2794 but also supports extensions to the initialization code: Lines starting
2795 with import are executed.
2796
Guido van Rossumf61f1662001-01-10 20:13:55 +00002797- There's a new module, warnings, which implements a mechanism for
2798 issuing and filtering warnings. There are some new built-in
2799 exceptions that serve as warning categories, and a new command line
2800 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2801 turns warnings into errors). warnings.warn(message[, category])
2802 issues a warning message; this can also be called from C as
2803 PyErr_Warn(category, message).
2804
2805- A new module xreadlines was added. This exports a single factory
2806 function, xreadlines(). The intention is that this code is the
2807 absolutely fastest way to iterate over all lines in an open
2808 file(-like) object:
2809
2810 import xreadlines
2811 for line in xreadlines.xreadlines(file):
2812 ...do something to line...
2813
2814 This is equivalent to the previous the speed record holder using
2815 file.readlines(sizehint). Note that if file is a real file object
2816 (as opposed to a file-like object), this is equivalent:
2817
2818 for line in file.xreadlines():
2819 ...do something to line...
2820
Tim Peters36cdad12000-12-29 02:06:45 +00002821- The bisect module has new functions bisect_left, insort_left,
2822 bisect_right and insort_right. The old names bisect and insort
2823 are now aliases for bisect_right and insort_right. XXX_right
2824 and XXX_left methods differ in what happens when the new element
2825 compares equal to one or more elements already in the list: the
2826 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002827 right. Code that doesn't care where equal elements end up should
2828 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002829
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002830- The new curses.panel module wraps the panel library that forms part
2831 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2832
Guido van Rossumf61f1662001-01-10 20:13:55 +00002833- The SocketServer module now sets the allow_reuse_address flag by
2834 default in the TCPServer class.
2835
2836- A new function, sys._getframe(), returns the stack frame pointer of
2837 the caller. This is intended only as a building block for
2838 higher-level mechanisms such as string interpolation.
2839
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002840- The pyexpat module supports a number of new handlers, which are
2841 available only in expat 1.2. If invocation of a callback fails, it
2842 will report an additional frame in the traceback. Parser objects
2843 participate now in garbage collection. If expat reports an unknown
2844 encoding, pyexpat will try to use a Python codec; that works only
2845 for single-byte charsets. The parser type objects is exposed as
2846 XMLParserObject.
2847
2848- xml.dom now offers standard definitions for symbolic node type and
2849 exception code constants, and a hierarchy of DOM exceptions. minidom
2850 was adjusted to use them.
2851
2852- The conformance of xml.dom.minidom to the DOM specification was
2853 improved. It detects a number of additional error cases; the
2854 previous/next relationship works even when the tree is modified;
2855 Node supports the normalize() method; NamedNodeMap, DocumentType and
2856 DOMImplementation classes were added; Element supports the
2857 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2858 method.
2859
Guido van Rossumf61f1662001-01-10 20:13:55 +00002860Build issues
2861
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002862- For Unix (and Unix-compatible) builds, configuration and building of
2863 extension modules is now greatly automated. Rather than having to
2864 edit the Modules/Setup file to indicate which modules should be
2865 built and where their include files and libraries are, a
2866 distutils-based setup.py script now takes care of building most
2867 extension modules. All extension modules built this way are built
2868 as shared libraries. Only a few modules that must be linked
2869 statically are still listed in the Setup file; you won't need to
2870 edit their configuration.
2871
2872- Python should now build out of the box on Cygwin. If it doesn't,
2873 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002874
2875- Python now always uses its own (renamed) implementation of getopt()
2876 -- there's too much variation among C library getopt()
2877 implementations.
2878
2879- C++ compilers are better supported; the CXX macro is always set to a
2880 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002881
Tim Petersd92dfe02000-12-12 01:18:41 +00002882Windows changes
2883
2884- select module: By default under Windows, a select() call
2885 can specify no more than 64 sockets. Python now boosts
2886 this Microsoft default to 512. If you need even more than
2887 that, see the MS docs (you'll need to #define FD_SETSIZE
2888 and recompile Python from source).
2889
Guido van Rossumf61f1662001-01-10 20:13:55 +00002890- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2891 subdirectory is no more!
2892
Tim Petersa3a3a032000-11-30 05:22:44 +00002893
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002894What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002895=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002896
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002897Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002898changes are in the file HISTORY. If you are making the jump directly
2899from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2900HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002901
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002902Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2903the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2904http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002905
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002906--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002907
2908======================================================================
2909
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002910What's new in 2.0 (since release candidate 1)?
2911==============================================
2912
2913Standard library
2914
2915- The copy_reg module was modified to clarify its intended use: to
2916 register pickle support for extension types, not for classes.
2917 pickle() will raise a TypeError if it is passed a class.
2918
2919- Fixed a bug in gettext's "normalize and expand" code that prevented
2920 it from finding an existing .mo file.
2921
2922- Restored support for HTTP/0.9 servers in httplib.
2923
Tim Peters989b7b92000-10-16 20:24:53 +00002924- The math module was changed to stop raising OverflowError in case of
2925 underflow, and return 0 instead in underflow cases. Whether Python
2926 used to raise OverflowError in case of underflow was platform-
2927 dependent (it did when the platform math library set errno to ERANGE
2928 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002929
2930- Fixed a bug in StringIO that occurred when the file position was not
2931 at the end of the file and write() was called with enough data to
2932 extend past the end of the file.
2933
2934- Fixed a bug that caused Tkinter error messages to get lost on
2935 Windows. The bug was fixed by replacing direct use of
2936 interp->result with Tcl_GetStringResult(interp).
2937
2938- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2939 redirect response.
2940
2941- Several changes were made to distutils: Some debugging code was
2942 removed from util. Fixed the installer used when an external zip
2943 program (like WinZip) is not found; the source code for this
2944 installer is in Misc/distutils. check_lib() was modified to behave
2945 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2946 test for whether installed modules are on sys.path was changed to
2947 use both normcase() and normpath().
2948
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002949- Several minor bugs were fixed in the xml package (the minidom,
2950 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002951
2952- The regression test driver (regrtest.py) behavior when invoked with
2953 -l changed: It now reports a count of objects that are recognized as
2954 garbage but not freed by the garbage collector.
2955
Tim Peters989b7b92000-10-16 20:24:53 +00002956- The regression test for the math module was changed to test
2957 exceptional behavior when the test is run in verbose mode. Python
2958 cannot yet guarantee consistent exception behavior across platforms,
2959 so the exception part of test_math is run only in verbose mode, and
2960 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002961
2962Internals
2963
2964- PyOS_CheckStack() has been disabled on Win64, where it caused
2965 test_sre to fail.
2966
2967Build issues
2968
2969- Changed compiler flags, so that gcc is always invoked with -Wall and
2970 -Wstrict-prototypes. Users compiling Python with GCC should see
2971 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002972 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002973 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002974
Tim Petersa3a3a032000-11-30 05:22:44 +00002975- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002976
2977Tools and other miscellany
2978
2979- The compiler in Tools/compiler was updated to support the new
2980 language features introduced in 2.0: extended print statement, list
2981 comprehensions, and augmented assignments. The new compiler should
2982 also be backwards compatible with Python 1.5.2; the compiler will
2983 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002984 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002985
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002986What's new in 2.0 release candidate 1 (since beta 2)?
2987=====================================================
2988
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002989What is release candidate 1?
2990
2991We believe that release candidate 1 will fix all known bugs that we
2992intend to fix for the 2.0 final release. This release should be a bit
2993more stable than the previous betas. We would like to see even more
2994widespread testing before the final release, so we are producing this
2995release candidate. The final release will be exactly the same unless
2996any show-stopping (or brown bag) bugs are found by testers of the
2997release candidate.
2998
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002999All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003000to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003001
3002Core language, builtins, and interpreter
3003
3004- A bug that caused crashes when __coerce__ was used with augmented
3005 assignment, e.g. +=, was fixed.
3006
3007- Raise ZeroDivisionError when raising zero to a negative number,
3008 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
3009 power operator and the result of math.pow(0.0, -2.0) will vary by
3010 platform. On Linux, it raises a ValueError.
3011
3012- A bug in Unicode string interpolation was fixed that occasionally
3013 caused errors with formats including "%%". For example, the
3014 following expression "%% %s" % u"abc" no longer raises a TypeError.
3015
3016- Compilation of deeply nested expressions raises MemoryError instead
3017 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
3018
3019- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
3020 rendering them useless. They are now written in binary mode again.
3021
3022Standard library
3023
3024- Keyword arguments are now accepted for most pattern and match object
3025 methods in SRE, the standard regular expression engine.
3026
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003027- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00003028 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003029
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003030- Several bugs in the Unicode handling and error handling in _tkinter
3031 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003032
3033- Fix memory management errors in Merge() and Tkapp_Call() routines.
3034
3035- Several changes were made to cStringIO to make it compatible with
3036 the file-like object interface and with StringIO. If operations are
3037 performed on a closed object, an exception is raised. The truncate
3038 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00003039 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003040
3041- There were many changes made to the linuxaudiodev module and its
3042 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00003043 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003044
3045 Note that this module is named poorly, because it should work
3046 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00003047 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003048
3049 The module now raises exceptions when errors occur instead of
3050 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
3051 audio) and defines a getptr() method that calls the
3052 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
3053
3054- The library_version attribute, introduced in an earlier beta, was
3055 removed because it can not be supported with early versions of the C
3056 readline library, which provides no way to determine the version at
3057 compile-time.
3058
3059- The binascii module is now enabled on Win64.
3060
Tim Peters46446d62000-10-09 21:19:31 +00003061- tokenize.py no longer suffers "recursion depth" errors when parsing
3062 programs with very long string literals.
3063
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003064Internals
3065
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003066- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003067 which is called when the interpreter starts up to determine where
3068 the standard library is installed. These vulnerabilities affect all
3069 previous versions of Python and can be exploited by setting very
3070 long values for PYTHONHOME or argv[0]. The risk is greatest for a
3071 setuid Python script, although use of the wrapper in
3072 Misc/setuid-prog.c will eliminate the vulnerability.
3073
3074- Fixed garbage collection bugs in instance creation that were
3075 triggered when errors occurred during initialization. The solution,
3076 applied in cPickle and in PyInstance_New(), is to call
3077 PyObject_GC_Init() after the initialization of the object's
3078 container attributes is complete.
3079
3080- pyexpat adds definitions of PyModule_AddStringConstant and
3081 PyModule_AddObject if the Python version is less than 2.0, which
3082 provides compatibility with PyXML on Python 1.5.2.
3083
3084- If the platform has a bogus definition for LONG_BIT (the number of
3085 bits in a long), an error will be reported at compile time.
3086
3087- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
3088 collection crashes and possibly other, unreported crashes.
3089
3090- Fixed a memory leak in _PyUnicode_Fini().
3091
3092Build issues
3093
3094- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003095 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00003096 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003097
3098- The mmap.PAGESIZE constant is now initialized using sysconf when
3099 possible, which eliminates a dependency on -lucb for Reliant UNIX.
3100
3101- The md5 file should now compile on all platforms.
3102
3103- The select module now compiles on platforms that do not define
3104 POLLRDNORM and related constants.
3105
3106- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00003107 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003108
Jeremy Hylton10921202000-10-09 18:34:12 +00003109- BeOS: A number of changes were made to the build and installation
3110 process. ar-fake now operates on a directory of object files.
3111 dl_export.h is gone, and its macros now appear on the mwcc command
3112 line during build on PPC BeOS.
3113
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003114- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00003115 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003116
3117- Cygwin: Support for shared libraries, Tkinter, and sockets.
3118
3119- SunOS 4.1.4_JL: Fix test for directory existence in configure.
3120
3121Tools and other miscellany
3122
3123- Removed debugging prints from main used with freeze.
3124
Tim Peters46446d62000-10-09 21:19:31 +00003125- IDLE auto-indent no longer crashes when it encounters Unicode
3126 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003127
3128What's new in 2.0 beta 2 (since beta 1)?
3129========================================
3130
3131Core language, builtins, and interpreter
3132
Tim Peters482c0212000-09-26 06:33:09 +00003133- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003134 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003135
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003136- Add -h and -V command line options to print the usage message and
3137 Python version number and exit immediately.
3138
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003139- eval() and exec accept Unicode objects as code parameters.
3140
3141- getattr() and setattr() now also accept Unicode objects for the
3142 attribute name, which are converted to strings using the default
3143 encoding before lookup.
3144
3145- Multiplication on string and Unicode now does proper bounds
3146 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
3147 string is too long."
3148
3149- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00003150 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003151
Jeremy Hylton1b618592000-09-26 05:32:36 +00003152
3153Standard library and extensions
3154
Guido van Rossum5b08f132001-04-16 02:05:23 +00003155- socket module: the OpenSSL code now adds support for RAND_status()
3156 and EGD (Entropy Gathering Device).
3157
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003158- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00003159 argument checking; it still takes no arguments.
3160
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003161- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003162
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003163- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003164
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003165- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003166
3167- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003168 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003169
3170- copy: Copy Unicode objects atomically.
3171
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003172- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003173
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003174- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003175
Fred Drake67233bc2000-09-26 16:40:27 +00003176- dbm: Add get() and setdefault() methods to dbm object. Add constant
3177 `library' to module that names the library used. Added doc strings
3178 and method names to error messages. Uses configure to determine
3179 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
3180 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003181
3182- distutils: Update to version 0.9.3.
3183
3184- dl: Add several dl.RTLD_ constants.
3185
3186- fpectl: Now supported on FreeBSD.
3187
3188- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
3189 found by the collector will be saved in gc.garbage. This is useful
3190 for debugging a program that creates reference cycles.
3191
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003192- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00003193 of HTTP class. Do not close socket on zero-length response. Do not
3194 crash when server sends invalid content-length header.
3195
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003196- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003197
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003198- marshal: When reading a short, sign-extend on platforms where shorts
3199 are bigger than 16 bits. When reading a long, repair the unportable
3200 sign extension that was being done for 64-bit machines. (It assumed
3201 that signed right shift sign-extends.)
3202
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003203- operator: Add contains(), invert(), __invert__() as aliases for
3204 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003205
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003206- os: Add support for popen2() and popen3() on all platforms where
3207 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003208
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003209- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00003210 clicking on a file in Explorer (or passing the file name to the
3211 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003212
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003213- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00003214 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003215
3216- pickle: Now raises ValueError when an invalid pickle that contains
3217 a non-string repr where a string repr was expected. This behavior
3218 matches cPickle.
3219
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003220- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003221
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003222- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003223
3224- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003225 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003226 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003227
3228- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003229 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003230
3231- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00003232 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00003233 few cycles during startup since the first call to
3234 setdefaultencoding() will initialize the codec registry and the
3235 encodings package.
3236
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003237- socket: Support for size hint in readlines() method of object returned
3238 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003239
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003240- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00003241 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00003242 is followed by whitespace.
3243
Tim Petersa3a3a032000-11-30 05:22:44 +00003244- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003245
3246- struct: Check ranges for bytes and shorts.
3247
3248- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003249 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003250
3251- Tkinter: Image objects are now guaranteed to have unique ids. Set
3252 event.delta to zero if Tk version doesn't support mousewheel.
3253 Removed some debugging prints.
3254
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003255- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003256
Fred Drake67233bc2000-09-26 16:40:27 +00003257- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003258 which works around a bug in Norton AntiVirus 2000 that leads directly
3259 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003260
3261- xml: New version detection code allows PyXML to override standard
3262 XML package if PyXML version is greater than 0.6.1.
3263
Fred Drake64bb3802000-09-26 16:21:35 +00003264- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
3265 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
3266 tree only for nodes which are sufficiently interesting to a specific
3267 application. Does not provide the HTML-specific extensions. Still
3268 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003269
Fred Drake64bb3802000-09-26 16:21:35 +00003270- xml.sax: SAX 2 support for Python, including all the handler
3271 interfaces needed to process XML 1.0 compliant XML. Some
3272 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003273
Fred Drake64bb3802000-09-26 16:21:35 +00003274- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
3275 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003276
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003277
Jeremy Hylton1b618592000-09-26 05:32:36 +00003278C API
3279
3280- Add three new convenience functions for module initialization --
3281 PyModule_AddObject(), PyModule_AddIntConstant(), and
3282 PyModule_AddStringConstant().
3283
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003284- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00003285 removed and add #error to Python.h if NULL isn't defined after
3286 #include of stdio.h.
3287
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003288- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00003289 backwards compatibility (at the source level) with old extensions.
3290
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003291- A wrapper API was added for signal() and sigaction(). Instead of
3292 either function, always use PyOS_getsig() to get a signal handler
3293 and PyOS_setsig() to set one. A new convenience typedef
3294 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003295
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003296- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00003297 internal data buffer and size of a string object -- or the default
3298 encoded version of a Unicode object.
3299
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003300- PyString_Size() and PyString_AsString() accept Unicode objects.
3301
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003302- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00003303 exists). INT_MAX and LONG_MAX will always be defined, even if
3304 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003305
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003306- PyFloat_FromString takes a second argument, pend, that was
3307 effectively useless. It is now officially useless but preserved for
3308 backwards compatibility. If the pend argument is not NULL, *pend is
3309 set to NULL.
3310
3311- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
3312 for the attribute name. See note on getattr() above.
3313
3314- A few bug fixes to argument processing for Unicode.
3315 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
3316 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
3317 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00003318 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003319
3320- Py_BuildValue accepts B format (for bgen-generated code).
3321
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003322
Jeremy Hylton1b618592000-09-26 05:32:36 +00003323Internals
3324
3325- On Unix, fix code for finding Python installation directory so that
3326 it works when argv[0] is a relative path.
3327
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00003328- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003329 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00003330 rather than by generating a copy of the object.
3331
Tim Peters482c0212000-09-26 06:33:09 +00003332- Several of the internal Unicode tables are much smaller now, and
3333 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003334
Jeremy Hylton97693b02000-09-26 17:42:51 +00003335- In the garbage collector: Fixed bug in collection of tuples. Fixed
3336 bug that caused some instances to be removed from the container set
3337 while they were still live. Fixed parsing in gc.set_debug() for
3338 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003339
3340- Fixed refcount problem in instance deallocation that only occurred
3341 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
3342
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003343- On Windows, getpythonregpath is now protected against null data in
3344 registry key.
3345
3346- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00003347 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003348
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003349
Jeremy Hylton1b618592000-09-26 05:32:36 +00003350Build and platform-specific issues
3351
3352- Better support of GNU Pth via --with-pth configure option.
3353
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003354- Python/C API now properly exposed to dynamically-loaded extension
3355 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003356
3357- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
3358 Don't define MS_SYNC to be zero when it is undefined. Added missing
3359 prototypes in posixmodule.c.
3360
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003361- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003362 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003363
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003364- Fix largefile support on older NetBSD systems and OpenBSD by adding
3365 define for TELL64.
3366
3367
3368Tools and other miscellany
3369
3370- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
3371
3372- freeze: The modulefinder now works with 2.0 opcodes.
3373
Tim Petersa3a3a032000-11-30 05:22:44 +00003374- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003375 Move hackery of sys.argv until after the Tk instance has been
3376 created, which allows the application-specific Tkinter
3377 initialization to be executed if present; also pass an explicit
3378 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00003379
Jeremy Hylton1b618592000-09-26 05:32:36 +00003380
3381What's new in 2.0 beta 1?
3382=========================
3383
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003384Source Incompatibilities
3385------------------------
3386
3387None. Note that 1.6 introduced several incompatibilities with 1.5.2,
3388such as single-argument append(), connect() and bind(), and changes to
3389str(long) and repr(float).
3390
3391
3392Binary Incompatibilities
3393------------------------
3394
3395- Third party extensions built for Python 1.5.x or 1.6 cannot be used
3396with Python 2.0; these extensions will have to be rebuilt for Python
33972.0.
3398
3399- On Windows, attempting to import a third party extension built for
3400Python 1.5.x or 1.6 results in an immediate crash; there's not much we
3401can do about this. Check your PYTHONPATH environment variable!
3402
3403- Python bytecode files (*.pyc and *.pyo) are not compatible between
3404releases.
3405
3406
3407Overview of Changes Since 1.6
3408-----------------------------
3409
3410There are many new modules (including brand new XML support through
3411the xml package, and i18n support through the gettext module); a list
3412of all new modules is included below. Lots of bugs have been fixed.
3413
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003414The process for making major new changes to the language has changed
3415since Python 1.6. Enhancements must now be documented by a Python
3416Enhancement Proposal (PEP) before they can be accepted.
3417
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003418There are several important syntax enhancements, described in more
3419detail below:
3420
3421 - Augmented assignment, e.g. x += 1
3422
3423 - List comprehensions, e.g. [x**2 for x in range(10)]
3424
3425 - Extended import statement, e.g. import Module as Name
3426
3427 - Extended print statement, e.g. print >> file, "Hello"
3428
3429Other important changes:
3430
3431 - Optional collection of cyclical garbage
3432
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003433Python Enhancement Proposal (PEP)
3434---------------------------------
3435
3436PEP stands for Python Enhancement Proposal. A PEP is a design
3437document providing information to the Python community, or describing
3438a new feature for Python. The PEP should provide a concise technical
3439specification of the feature and a rationale for the feature.
3440
3441We intend PEPs to be the primary mechanisms for proposing new
3442features, for collecting community input on an issue, and for
3443documenting the design decisions that have gone into Python. The PEP
3444author is responsible for building consensus within the community and
3445documenting dissenting opinions.
3446
3447The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003448
3449Augmented Assignment
3450--------------------
3451
3452This must have been the most-requested feature of the past years!
3453Eleven new assignment operators were added:
3454
Guido van Rossume905e952000-09-05 12:42:46 +00003455 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003456
3457For example,
3458
3459 A += B
3460
3461is similar to
3462
3463 A = A + B
3464
3465except that A is evaluated only once (relevant when A is something
3466like dict[index].attr).
3467
3468However, if A is a mutable object, A may be modified in place. Thus,
3469if A is a number or a string, A += B has the same effect as A = A+B
3470(except A is only evaluated once); but if a is a list, A += B has the
3471same effect as A.extend(B)!
3472
3473Classes and built-in object types can override the new operators in
3474order to implement the in-place behavior; the not-in-place behavior is
3475used automatically as a fallback when an object doesn't implement the
3476in-place behavior. For classes, the method name is derived from the
3477method name for the corresponding not-in-place operator by inserting
3478an 'i' in front of the name, e.g. __iadd__ implements in-place
3479__add__.
3480
3481Augmented assignment was implemented by Thomas Wouters.
3482
3483
3484List Comprehensions
3485-------------------
3486
3487This is a flexible new notation for lists whose elements are computed
3488from another list (or lists). The simplest form is:
3489
3490 [<expression> for <variable> in <sequence>]
3491
Guido van Rossum56db0952000-09-06 23:34:25 +00003492For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003493This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003494
3495You can also add a condition:
3496
3497 [<expression> for <variable> in <sequence> if <condition>]
3498
3499For example, [w for w in words if w == w.lower()] would yield the list
3500of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003501than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003502
3503You can also have nested for loops and more than one 'if' clause. For
3504example, here's a function that flattens a sequence of sequences::
3505
3506 def flatten(seq):
3507 return [x for subseq in seq for x in subseq]
3508
3509 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3510
3511This prints
3512
3513 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3514
3515List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003516Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003517
3518
3519Extended Import Statement
3520-------------------------
3521
3522Many people have asked for a way to import a module under a different
3523name. This can be accomplished like this:
3524
3525 import foo
3526 bar = foo
3527 del foo
3528
3529but this common idiom gets old quickly. A simple extension of the
3530import statement now allows this to be written as follows:
3531
3532 import foo as bar
3533
3534There's also a variant for 'from ... import':
3535
3536 from foo import bar as spam
3537
3538This also works with packages; e.g. you can write this:
3539
3540 import test.regrtest as regrtest
3541
3542Note that 'as' is not a new keyword -- it is recognized only in this
3543context (this is only possible because the syntax for the import
3544statement doesn't involve expressions).
3545
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003546Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003547
3548
3549Extended Print Statement
3550------------------------
3551
3552Easily the most controversial new feature, this extension to the print
3553statement adds an option to make the output go to a different file
3554than the default sys.stdout.
3555
3556For example, to write an error message to sys.stderr, you can now
3557write:
3558
3559 print >> sys.stderr, "Error: bad dog!"
3560
3561As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003562evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003563
3564 print >> None, "Hello world"
3565
3566is equivalent to
3567
3568 print "Hello world"
3569
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003570Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003571
3572
3573Optional Collection of Cyclical Garbage
3574---------------------------------------
3575
3576Python is now equipped with a garbage collector that can hunt down
3577cyclical references between Python objects. It's no replacement for
3578reference counting; in fact, it depends on the reference counts being
3579correct, and decides that a set of objects belong to a cycle if all
3580their reference counts can be accounted for from their references to
3581each other. This devious scheme was first proposed by Eric Tiedemann,
3582and brought to implementation by Neil Schemenauer.
3583
3584There's a module "gc" that lets you control some parameters of the
3585garbage collection. There's also an option to the configure script
3586that lets you enable or disable the garbage collection. In 2.0b1,
3587it's on by default, so that we (hopefully) can collect decent user
3588experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003589performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003590off by default in the final 2.0 release.
3591
3592
3593Smaller Changes
3594---------------
3595
3596A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3597map(None, seq1, seq2, ...) when the sequences have the same length;
3598i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3599the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003600zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003601
3602sys.version_info is a tuple (major, minor, micro, level, serial).
3603
3604Dictionaries have an odd new method, setdefault(key, default).
3605dict.setdefault(key, default) returns dict[key] if it exists; if not,
3606it sets dict[key] to default and returns that value. Thus:
3607
3608 dict.setdefault(key, []).append(item)
3609
3610does the same work as this common idiom:
3611
3612 if not dict.has_key(key):
3613 dict[key] = []
3614 dict[key].append(item)
3615
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003616There are two new variants of SyntaxError that are raised for
3617indentation-related errors: IndentationError and TabError.
3618
3619Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3620escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003621
3622The limits on the size of expressions and file in Python source code
3623have been raised from 2**16 to 2**32. Previous versions of Python
3624were limited because the maximum argument size the Python VM accepted
3625was 2**16. This limited the size of object constructor expressions,
3626e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3627limit was raised thanks to a patch by Charles Waldman that effectively
3628fixes the problem. It is now much more likely that you will be
3629limited by available memory than by an arbitrary limit in Python.
3630
3631The interpreter's maximum recursion depth can be modified by Python
3632programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3633limit is the maximum number of recursive calls that can be made by
3634Python code. The limit exists to prevent infinite recursion from
3635overflowing the C stack and causing a core dump. The default value is
36361000. The maximum safe value for a particular platform can be found
3637by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003638
3639New Modules and Packages
3640------------------------
3641
3642atexit - for registering functions to be called when Python exits.
3643
3644imputil - Greg Stein's alternative API for writing custom import
3645hooks.
3646
3647pyexpat - an interface to the Expat XML parser, contributed by Paul
3648Prescod.
3649
3650xml - a new package with XML support code organized (so far) in three
3651subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3652would fill a volume. There's a special feature whereby a
3653user-installed package named _xmlplus overrides the standard
3654xmlpackage; this is intended to give the XML SIG a hook to distribute
3655backwards-compatible updates to the standard xml package.
3656
3657webbrowser - a platform-independent API to launch a web browser.
3658
3659
Guido van Rossume905e952000-09-05 12:42:46 +00003660Changed Modules
3661---------------
3662
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003663array -- new methods for array objects: count, extend, index, pop, and
3664remove
3665
3666binascii -- new functions b2a_hex and a2b_hex that convert between
3667binary data and its hex representation
3668
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003669calendar -- Many new functions that support features including control
3670over which day of the week is the first day, returning strings instead
3671of printing them. Also new symbolic constants for days of week,
3672e.g. MONDAY, ..., SUNDAY.
3673
3674cgi -- FieldStorage objects have a getvalue method that works like a
3675dictionary's get method and returns the value attribute of the object.
3676
3677ConfigParser -- The parser object has new methods has_option,
3678remove_section, remove_option, set, and write. They allow the module
3679to be used for writing config files as well as reading them.
3680
3681ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003682optionally support the RFC 959 REST command.
3683
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003684gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003685
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003686httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3687the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003688
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003689locale -- implement getdefaultlocale for Win32 and Macintosh
3690
3691marshal -- no longer dumps core when marshaling deeply nested or
3692recursive data structures
3693
3694os -- new functions isatty, seteuid, setegid, setreuid, setregid
3695
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003696os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3697support under Unix.
3698
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003699os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003700
3701os.path -- fix semantics of os.path.commonprefix
3702
3703smtplib -- support for sending very long messages
3704
3705socket -- new function getfqdn()
3706
3707readline -- new functions to read, write and truncate history files.
3708The readline section of the library reference manual contains an
3709example.
3710
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003711select -- add interface to poll system call
3712
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003713shutil -- new copyfileobj function
3714
3715SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3716HTTP server.
3717
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003718Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003719
3720urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003721e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003722
3723whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003724
3725
3726Obsolete Modules
3727----------------
3728
3729None. However note that 1.6 made a whole slew of modules obsolete:
3730stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3731poly, zmod, strop, util, whatsound.
3732
3733
3734Changed, New, Obsolete Tools
3735----------------------------
3736
Tim Peters8b092332000-09-05 20:15:25 +00003737None.
Guido van Rossume905e952000-09-05 12:42:46 +00003738
3739
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003740C-level Changes
3741---------------
3742
3743Several cleanup jobs were carried out throughout the source code.
3744
3745All C code was converted to ANSI C; we got rid of all uses of the
3746Py_PROTO() macro, which makes the header files a lot more readable.
3747
3748Most of the portability hacks were moved to a new header file,
3749pyport.h; several other new header files were added and some old
3750header files were removed, in an attempt to create a more rational set
3751of header files. (Few of these ever need to be included explicitly;
3752they are all included by Python.h.)
3753
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003754Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003755and Win64, especially for the new Intel Itanium processor. Mick also
3756added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003757
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003758The C APIs to return an object's size have been update to consistently
3759use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3760previous versions, the abstract interfaces used PyXXX_Length and the
3761concrete interfaces used PyXXX_Size. The old names,
3762e.g. PyObject_Length, are still available for backwards compatibility
3763at the API level, but are deprecated.
3764
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003765The PyOS_CheckStack function has been implemented on Windows by
3766Fredrik Lundh. It prevents Python from failing with a stack overflow
3767on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003768
3769The GC changes resulted in creation of two new slots on object,
3770tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003771the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003772
3773The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003774C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003775
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003776PyErr_Format has been updated to automatically calculate the size of
3777the buffer needed to hold the formatted result string. This change
3778prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003779
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003780New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003781
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003782PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3783that are the same as their non-Ex counterparts except they take an
3784extra flag argument that tells them to close the file when done.
3785
3786XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003787
Tim Peters8b092332000-09-05 20:15:25 +00003788
3789Windows Changes
3790---------------
3791
3792New popen2/popen3/peopen4 in os module (see Changed Modules above).
3793
3794os.popen is much more usable on Windows 95 and 98. See Microsoft
3795Knowledge Base article Q150956. The Win9x workaround described there
3796is implemented by the new w9xpopen.exe helper in the root of your
3797Python installation. Note that Python uses this internally; it is not
3798a standalone program.
3799
3800Administrator privileges are no longer required to install Python
3801on Windows NT or Windows 2000. If you have administrator privileges,
3802Python's registry info will be written under HKEY_LOCAL_MACHINE.
3803Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003804under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003805uses of Python, but will prevent some advanced uses from working
3806(for example, running a Python script as an NT service, or possibly
3807from CGI).
3808
3809[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3810installer; instead, it installs the needed Tcl/Tk files directly in the
3811Python directory. If you already have a Tcl/Tk installation, this
3812wastes some disk space (about 4 Megs) but avoids problems with
3813conflicting Tcl/Tk installations, and makes it much easier for Python
3814to ensure that Tcl/Tk can find all its files.
3815
3816[This was new in 1.6] The Windows installer now installs by default in
3817\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3818
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003819
3820Updates to the changes between 1.5.2 and 1.6
3821--------------------------------------------
3822
3823The 1.6 NEWS file can't be changed after the release is done, so here
3824is some late-breaking news:
3825
3826New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3827and changes to getlocale() and setlocale().
3828
3829The new module is now enabled per default.
3830
3831It is not true that the encodings codecs cannot be used for normal
3832strings: the string.encode() (which is also present on 8-bit strings
3833!) allows using them for 8-bit strings too, e.g. to convert files from
3834cp1252 (Windows) to latin-1 or vice-versa.
3835
3836Japanese codecs are available from Tamito KAJIYAMA:
3837http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3838
3839
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003840======================================================================