blob: d08bc34286109c2028a5db0cf19f207496f12dfd [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
Walter Dörwald5ccaf8f2002-09-06 16:15:58 +0000324- mimetypes has two new functions: guess_all_extensions() which
325 returns a list of all known extensions for a mime type, and
326 add_type() which adds one mapping between a mime type and
327 an extension to the database.
328
Guido van Rossumd8ab35c2002-08-19 16:25:46 +0000329- New module: sets, defines the class Set that implements a mutable
330 set type using the keys of a dict to represent the set. There's
331 also a class ImmutableSet which is useful when you need sets of sets
332 or when you need to use sets as dict keys, and a class BaseSet which
333 is the base class of the two. (This is not documented yet, but
334 help(sets) gives a wealth of information.)
335
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +0000336- Added operator.pow(a,b) which is equivalent to a**b.
337
Tim Peters012c0a32002-08-16 03:40:07 +0000338- random.randrange(-sys.maxint-1, sys.maxint) no longer raises
339 OverflowError. That is, it now accepts any combination of 'start'
340 and 'stop' arguments so long as each is in the range of Python's
341 bounded integers.
342
Guido van Rossum4a57c332002-08-02 18:05:20 +0000343- New "algorithms" module: heapq, implements a heap queue. Thanks to
344 Kevin O'Connor for the code and François Pinard for an entertaining
345 write-up explaining the theory and practical uses of heaps.
346
Marc-André Lemburg58e2ff22002-07-12 14:40:04 +0000347- New encoding for the Palm OS character set: palmos.
348
Tim Peters943382c2002-07-07 03:59:34 +0000349- binascii.crc32() and the zipfile module had problems on some 64-bit
350 platforms. These have been fixed. On a platform with 8-byte C longs,
351 crc32() now returns a signed-extended 4-byte result, so that its value
352 as a Python int is equal to the value computed a 32-bit platform.
353
Martin v. Löwis7d650ca2002-06-30 15:05:00 +0000354- xml.dom.minidom.toxml and toprettyxml now take an optional encoding
355 argument.
356
Guido van Rossum9f7549b2002-06-10 21:39:42 +0000357- Some fixes in the copy module: when an object is copied through its
358 __reduce__ method, there was no check for a __setstate__ method on
359 the result [SF patch 565085]; deepcopy should treat instances of
360 custom metaclasses the same way it treats instances of type 'type'
361 [SF patch 560794].
362
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000363- Sockets now support timeout mode. After s.settimeout(T), where T is
364 a float expressing seconds, subsequent operations raise an exception
365 if they cannot be completed within T seconds. To disable timeout
Guido van Rossum79f0a102002-07-23 03:32:08 +0000366 mode, use s.settimeout(None). There's also a module function,
367 socket.setdefaulttimeout(T), which sets the default for all sockets
368 created henceforth.
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000369
370- getopt.gnu_getopt was added. This supports GNU-style option
371 processing, where options can be mixed with non-option arguments.
Martin v. Löwis446a25f2002-06-06 10:58:36 +0000372
Michael W. Hudsonb0dc1a32002-06-04 18:27:35 +0000373- Stop using strings for exceptions. String objects used for
374 exceptions are now classes deriving from Exception. The objects
375 changed were: Tkinter.TclError, bdb.BdbQuit, macpath.norm_error,
376 tabnanny.NannyNag, and xdrlib.Error.
Neal Norwitzb5b5a262002-06-04 17:14:07 +0000377
Walter Dörwald474458d2002-06-04 15:16:29 +0000378- Constants BOM_UTF8, BOM_UTF16, BOM_UTF16_LE, BOM_UTF16_BE,
379 BOM_UTF32, BOM_UTF32_LE and BOM_UTF32_BE that represent the Byte
380 Order Mark in UTF-8, UTF-16 and UTF-32 encodings for little and
381 big endian systems were added to the codecs module. The old names
382 BOM32_* and BOM64_* were off by a factor of 2.
383
Guido van Rossumf9257822002-06-18 20:43:18 +0000384- Added conversion functions math.degrees() and math.radians().
Raymond Hettinger87f59ee2002-05-13 04:17:32 +0000385
Raymond Hettinger9b1df1d2002-05-12 06:07:21 +0000386- ftplib.retrlines() now tests for callback is None rather than testing
387 for False. Was causing an error when given a callback object which
388 was callable but also returned len() as zero. The change may
389 create new breakage if the caller relied on the undocumented behavior
390 and called with callback set to [] or some other False value not
391 identical to None.
392
Tim Peters46c04e12002-05-05 20:40:00 +0000393- random.gauss() uses a piece of hidden state used by nothing else,
394 and the .seed() and .whseed() methods failed to reset it. In other
395 words, setting the seed didn't completely determine the sequence of
396 results produced by random.gauss(). It does now. Programs repeatedly
397 mixing calls to a seed method with calls to gauss() may see different
398 results now.
399
Fred Drake7f781c92002-05-01 20:33:53 +0000400- The pickle.Pickler class grew a clear_memo() method to mimic that
401 provided by cPickle.Pickler.
402
Tim Peters81b92512002-04-29 01:37:32 +0000403- difflib's SequenceMatcher class now does a dynamic analysis of
404 which elements are so frequent as to constitute noise. For
405 comparing files as sequences of lines, this generally works better
406 than the IS_LINE_JUNK function, and function ndiff's linejunk
407 argument defaults to None now as a result. A happy benefit is
408 that SequenceMatcher may run much faster now when applied
409 to large files with many duplicate lines (for example, C program
410 text with lots of repeated "}" and "return NULL;" lines).
411
Guido van Rossum256705b2002-04-23 13:29:43 +0000412- New Text.dump() method in Tkinter module.
413
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000414- New distutils commands for building packagers were added to
415 support pkgtool on Solaris and swinstall on HP-UX.
416
417- distutils now has a new abstract binary packager base class
418 command/bdist_packager, which simplifies writing packagers.
419 This will hopefully provide the missing bits to encourage
420 people to submit more packagers, e.g. for Debian, FreeBSD
421 and other systems.
422
Guido van Rossumf9257822002-06-18 20:43:18 +0000423- The UTF-16, -LE and -BE stream readers now raise a
424 NotImplementedError for all calls to .readline(). Previously, they
425 used to just produce garbage or fail with an encoding error --
426 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 +0000427 work well with these.
428
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000429- compileall now supports quiet operation.
430
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000431- The BaseHTTPServer now implements optional HTTP/1.1 persistent
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000432 connections.
433
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000434- socket module: the SSL support was broken out of the main
435 _socket module C helper and placed into a new _ssl helper
436 which now gets imported by socket.py if available and working.
437
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000438- encodings package: added aliases for all supported IANA character
439 sets
440
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000441- ftplib: to safeguard the user's privacy, anonymous login will use
442 "anonymous@" as default password, rather than the real user and host
443 name.
444
Fred Drake36736122002-01-10 13:50:31 +0000445- webbrowser: tightened up the command passed to os.system() so that
446 arbitrary shell code can't be executed because a bogus URL was
447 passed in.
448
Tim Peters11bd9942002-02-01 00:52:29 +0000449- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000450 gettext.find an optional all argument. Translations will now fallback
451 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000452
Martin v. Löwis9668b932002-01-12 11:27:42 +0000453- distutils bdist commands now offer a --skip-build option.
454
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000455- warnings.warn now accepts a Warning instance as first argument.
456
Fred Drakefed7e852002-04-04 19:36:15 +0000457- The xml.sax.expatreader.ExpatParser class will no longer create
458 circular references by using itself as the locator that gets passed
459 to the content handler implementation. [SF bug #535474]
460
Barry Warsaw47f3e2c2002-05-20 00:14:24 +0000461- The email.Parser.Parser class now properly parses strings regardless
462 of their line endings, which can be any of \r, \n, or \r\n (CR, LF,
463 or CRLF). Also, the Header class's constructor default arguments
464 has changed slightly so that an explicit maxlinelen value is always
465 honored.
466
Tim Petersaf8446f2001-12-21 21:36:50 +0000467Tools/Demos
468
Fred Drake40813b12002-08-05 15:24:19 +0000469- IDLE supports the new encoding declarations (PEP 263); it can also
470 deal with legacy 8-bit files if they use the locale's encoding. It
471 allows non-ASCII strings in the interactive shell and executes them
472 in the locale's encoding.
Martin v. Löwis98ce7b72002-08-05 15:11:26 +0000473
Marc-André Lemburg46260092002-04-04 16:17:11 +0000474- freeze.py now produces binaries which can import shared modules,
475 unlike before when this failed due to missing symbol exports in
476 the generated binary.
477
Tim Petersaf8446f2001-12-21 21:36:50 +0000478Build
479
Tim Petersf47630f2002-08-01 02:34:51 +0000480- The public Python C API will generally be declared using PyAPI_FUNC
Neal Norwitz1389f3e2002-07-22 13:21:10 +0000481 and PyAPI_DATA macros, while Python extension module init functions
482 will be declared with PyMODINIT_FUNC. DL_EXPORT/DL_IMPORT macros
483 are deprecated.
484
Tim Petersc6a3ff62002-07-08 22:11:52 +0000485- A bug was fixed that could cause COUNT_ALLOCS builds to segfault, or
486 get into infinite loops, when a new-style class got garbage-collected.
487 Unfortunately, to avoid this, the way COUNT_ALLOCS works requires
488 that new-style classes be immortal in COUNT_ALLOCS builds. Note that
489 COUNT_ALLOCS is not enabled by default, in either release or debug
490 builds, and that new-style classes are immortal only in COUNT_ALLOCS
491 builds.
492
Tim Peters943382c2002-07-07 03:59:34 +0000493- Compiling out the cyclic garbage collector is no longer an option.
494 The old symbol WITH_CYCLE_GC is now ignored, and Python.h arranges
495 that it's always defined (for the benefit of any extension modules
496 that may be conditionalizing on it). A bonus is that any extension
497 type participating in cyclic gc can choose to participate in the
498 Py_TRASHCAN mechanism now too; in the absence of cyclic gc, this used
499 to require editing the core to teach the trashcan mechanism about the
500 new type.
501
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000502- According to Annex F of the current C standard,
Tim Peters1de41bf2002-07-03 03:31:20 +0000503
504 The Standard C macro HUGE_VAL and its float and long double analogs,
505 HUGE_VALF and HUGE_VALL, expand to expressions whose values are
506 positive infinities.
507
508 Python only uses the double HUGE_VAL, and only to #define its own symbol
509 Py_HUGE_VAL. Some platforms have incorrect definitions for HUGE_VAL.
510 pyport.h used to try to worm around that, but the workarounds triggered
511 other bugs on other platforms, so we gave up. If your platform defines
512 HUGE_VAL incorrectly, you'll need to #define Py_HUGE_VAL to something
513 that works on your platform. The only instance of this I'm sure about
514 is on an unknown subset of Cray systems, described here:
515
516 http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm
517
518 Presumably 2.3a1 breaks such systems. If anyone uses such a system, help!
519
Martin v. Löwisa3fb4f72002-06-09 13:33:54 +0000520- The configure option --without-doc-strings can be used to remove the
521 doc strings from the builtin functions and modules; this reduces the
522 size of the executable.
523
Guido van Rossumadd88062002-08-15 14:01:14 +0000524- The universal newlines option (PEP 278) is on by default. On Unix
525 it can be disabled by passing --without-universal-newlines to the
526 configure script. On other platforms, remove
527 WITH_UNIVERSAL_NEWLINES from pyconfig.h.
Tim Peters639295f2002-04-21 07:30:30 +0000528
Martin v. Löwis1142de32002-03-29 16:28:31 +0000529- On Unix, a shared libpython2.3.so can be created with --enable-shared.
530
Tim Peters8deda702002-03-30 10:06:07 +0000531- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
532 preprocessor symbols were eliminated. The internal decisions they
533 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000534
Fred Drake7d28b732002-05-02 21:17:00 +0000535- The tools used to build the documentation now work under Cygwin as
536 well as Unix.
537
Skip Montanaro57454e52002-06-14 20:30:31 +0000538- The bsddb and dbm module builds have been changed to try and avoid version
539 skew problems and disable linkage with Berkeley DB 1.85 unless the
540 installer knows what s/he's doing. See the section on building these
541 modules in the README file for details.
542
Tim Petersaf8446f2001-12-21 21:36:50 +0000543C API
544
Guido van Rossum45ec02a2002-08-19 21:43:18 +0000545- The string object's layout has changed: the pointer member
546 ob_sinterned has been replaced by an int member ob_sstate. On some
547 platforms (e.g. most 64-bit systems) this may change the offset of
548 the ob_sval member, so as a precaution the API_VERSION has been
549 incremented. The apparently unused feature of "indirect interned
550 strings", supported by the ob_sinterned member, is gone. Interned
551 strings are now usually mortal; theres a new API,
552 PyString_InternImmortal() that creates immortal interned strings.
553 (The ob_sstate member can only take three values; however, while
554 making it a char saves a few bytes per string object on average, in
555 it also slowed things down a bit because ob_sval was no longer
556 aligned.)
557
Guido van Rossumfdb86482002-08-14 21:20:32 +0000558- The Py_InitModule*() functions now accept NULL for the 'methods'
559 argument. Modules without global functions are becoming more common
560 now that factories can be types rather than functions.
561
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +0000562- New C API PyUnicode_FromOrdinal() which exposes unichr() at C
563 level.
564
Thomas Heller085358a2002-07-29 14:27:41 +0000565- New functions PyErr_SetExcFromWindowsErr() and
566 PyErr_SetExcFromWindowsErrWithFilename(). Similar to
567 PyErr_SetFromWindowsErrWithFilename() and
568 PyErr_SetFromWindowsErr(), but they allow to specify
569 the exception type to raise. Available on Windows.
570
Tim Peters7c321a82002-07-09 02:57:01 +0000571- Py_FatalError() is now declared as taking a const char* argument. It
572 was previously declared without const. This should not affect working
573 code.
574
Martin v. Löwis01f94bd2002-05-08 08:44:21 +0000575- Added new macro PySequence_ITEM(o, i) that directly calls
576 sq_item without rechecking that o is a sequence and without
577 adjusting for negative indices.
578
Fred Draked0ba6362002-05-02 21:28:26 +0000579- PyRange_New() now raises ValueError if the fourth argument is not 1.
580 This is part of the removal of deprecated features of the xrange
581 object.
582
Guido van Rossum517c7d42002-04-26 02:49:14 +0000583- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
584 coercion if both arguments have the same type but this type has the
585 CHECKTYPES flag set. This is to better support proxies.
586
Neil Schemenauer9344b142002-04-12 23:00:08 +0000587- The type of tp_free has been changed from "void (*)(PyObject *)" to
588 "void (*)(void *)".
589
590- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
591
Guido van Rossum0986d822002-04-08 01:38:42 +0000592- A type can now inherit its metatype from its base type. Previously,
593 when PyType_Ready() was called, if ob_type was found to be NULL, it
594 was always set to &PyType_Type; now it is set to base->ob_type,
595 where base is tp_base, defaulting to &PyObject_Type.
596
597- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
598
Neil Schemenauerc9abc1d2002-05-08 14:14:41 +0000599- The PyCore_* family of APIs have been removed.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000600
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000601- The "u#" parser marker will now pass through Unicode objects as-is
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000602 without going through the buffer API.
603
Martin v. Löwis7198a522002-01-01 19:59:11 +0000604- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
605
Tim Peters10a3bb52001-12-25 19:07:38 +0000606- An old #define of ANY as void has been removed from pyport.h. This
607 hasn't been used since Python's pre-ANSI days, and the #define has
608 been marked as obsolete since then. SF bug 495548 says it created
609 conflicts with other packages, so keeping it around wasn't harmless.
610
Tim Petersaf8446f2001-12-21 21:36:50 +0000611- Because Python's magic number scheme broke on January 1st, we decided
612 to stop Python development. Thanks for all the fish!
613
Tim Petersfb05db22002-03-11 00:24:00 +0000614- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000615 scheme to a new one. See Python/import.c for details.
616
Tim Petersaf8446f2001-12-21 21:36:50 +0000617New platforms
618
Martin v. Löwisf90ae202002-06-11 06:22:31 +0000619- AtheOS is now supported.
620
Andrew MacIntyre161ad0e2002-08-04 07:25:58 +0000621- the EMX runtime environment on OS/2 is now supported.
622
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000623- GNU/Hurd is now supported.
624
Tim Petersaf8446f2001-12-21 21:36:50 +0000625Tests
626
627Windows
628
Tim Peters08e72952002-04-16 20:48:01 +0000629- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
630 of that has been fixed in the installer (disabled Wise's "delete in-
631 use files" uninstall option).
632
Guido van Rossum181e41a2002-04-06 00:23:25 +0000633- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
634
Tim Peters33187922002-04-04 20:02:04 +0000635- The installer now installs Start menu shortcuts under (the local
636 equivalent of) "All Users" when doing an Admin install.
637
Tim Petersfb05db22002-03-11 00:24:00 +0000638- file.truncate([newsize]) now works on Windows for all newsize values.
639 It used to fail if newsize didn't fit in 32 bits, reflecting a
640 limitation of MS _chsize (which is no longer used).
641
Tim Petersab034fa2002-02-01 11:27:43 +0000642- os.waitpid() is now implemented for Windows, and can be used to block
643 until a specified process exits. This is similar to, but not exactly
644 the same as, os.waitpid() on POSIX systems. If you're waiting for
645 a specific process whose pid was obtained from one of the spawn()
646 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000647 See the docs for details. The docs were changed to clarify that
648 spawn functions return, and waitpid requires, a process handle on
649 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000650
Tim Peters11bd9942002-02-01 00:52:29 +0000651- New tempfile.TemporaryFile implementation for Windows: this doesn't
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000652 need a TemporaryFileWrapper wrapper anymore, and should be immune
Tim Peters11bd9942002-02-01 00:52:29 +0000653 to a nasty problem: before 2.3, if you got a temp file on Windows, it
654 got wrapped in an object whose close() method first closed the
655 underlying file, then deleted the file. This usually worked fine.
656 However, the spawn family of functions on Windows create (at a low C
657 level) the same set of open files in the spawned process Q as were
658 open in the spawning process P. If a temp file f was among them, then
659 doing f.close() in P first closed P's C-level file handle on f, but Q's
660 C-level file handle on f remained open, so the attempt in P to delete f
661 blew up with a "Permission denied" error (Windows doesn't allow
662 deleting open files). This was surprising, subtle, and difficult to
663 work around.
664
665- The os module now exports all the symbolic constants usable with the
666 low-level os.open() on Windows: the new constants in 2.3 are
667 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
668 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
669 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
670 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
671 (so specify both if you want both; note that neither is useful unless
672 specified with O_CREAT too).
673
Tim Petersaf8446f2001-12-21 21:36:50 +0000674Mac
675
676
Tim Peters909c0912001-12-14 23:16:18 +0000677What's New in Python 2.2 final?
678Release date: 21-Dec-2001
679===============================
680
681Type/class unification and new-style classes
682
Barry Warsaw52acb492001-12-21 20:04:22 +0000683- pickle.py, cPickle: allow pickling instances of new-style classes
684 with a custom metaclass.
685
Tim Peters909c0912001-12-14 23:16:18 +0000686Core and builtins
687
Barry Warsaw52acb492001-12-21 20:04:22 +0000688- weakref proxy object: when comparing, unwrap both arguments if both
689 are proxies.
690
Tim Peters909c0912001-12-14 23:16:18 +0000691Extension modules
692
Barry Warsaw52acb492001-12-21 20:04:22 +0000693- binascii.b2a_base64(): fix a potential buffer overrun when encoding
694 very short strings.
695
696- cPickle: the obscure "fast" mode was suspected of causing stack
697 overflows on the Mac. Hopefully fixed this by setting the recursion
698 limit much smaller. If the limit is too low (it only affects
699 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
700 when compiling cPickle.c (or in pyconfig.h).
701
Tim Peters909c0912001-12-14 23:16:18 +0000702Library
703
Barry Warsaw52acb492001-12-21 20:04:22 +0000704- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
705 close or delete time).
706
707- rfc822.py: fixed a bug where the address '<>' was converted to None
708 instead of an empty string (also fixes the email.Utils module).
709
710- xmlrpclib.py: version 1.0.0; uses precision for doubles.
711
712- test suite: the pickle and cPickle tests were not executing any code
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000713 when run from the standard regression test.
Barry Warsaw52acb492001-12-21 20:04:22 +0000714
Tim Peters909c0912001-12-14 23:16:18 +0000715Tools/Demos
716
717Build
718
719C API
720
721New platforms
722
723Tests
724
725Windows
726
Barry Warsaw52acb492001-12-21 20:04:22 +0000727- distutils package: fixed broken Windows installers (bdist_wininst).
728
729- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
730 instances are deleted at process exit time.
731
732- socket.py: prevent mysterious warnings when socket instances are
733 deleted at process exit time.
734
735- posixmodule.c: fix a Windows crash with stat() of a filename ending
736 in backslash.
737
Tim Peters909c0912001-12-14 23:16:18 +0000738Mac
739
Barry Warsaw52acb492001-12-21 20:04:22 +0000740- The Carbon toolbox modules have been upgraded to Universal Headers
741 3.4, and experimental CoreGraphics and CarbonEvents modules have
742 been added. All only for framework-enabled MacOSX.
743
Tim Peters909c0912001-12-14 23:16:18 +0000744
Tim Peters6272dfd2001-12-13 19:34:00 +0000745What's New in Python 2.2c1?
746Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000747===========================
748
749Type/class unification and new-style classes
750
Barry Warsaw06557452001-12-14 20:47:12 +0000751- Guido's tutorial introduction to the new type/class features has
752 been extensively updated. See
753
754 http://www.python.org/2.2/descrintro.html
755
756 That remains the primary documentation in this area.
757
Guido van Rossum33bab012001-12-05 22:45:48 +0000758- Fixed a leak: instance variables declared with __slots__ were never
759 deleted!
760
Guido van Rossum4b800852001-12-03 00:54:52 +0000761- The "delete attribute" method of descriptor objects is called
762 __delete__, not __del__. In previous releases, it was mistakenly
763 called __del__, which created an unfortunate overloading condition
764 with finalizers. (The "get attribute" and "set attribute" methods
765 are still called __get__ and __set__, respectively.)
766
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000767- Some subtle issues with the super built-in were fixed:
768
769 (a) When super itself is subclassed, its __get__ method would still
770 return an instance of the base class (i.e., of super).
771
772 (b) super(C, C()).__class__ would return C rather than super. This
773 is confusing. To fix this, I decided to change the semantics of
774 super so that it only applies to code attributes, not to data
775 attributes. After all, overriding data attributes is not
776 supported anyway.
777
778 (c) The __get__ method didn't check whether the argument was an
779 instance of the type used in creation of the super instance.
780
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000781- Previously, hash() of an instance of a subclass of a mutable type
782 (list or dictionary) would return some value, rather than raising
783 TypeError. This has been fixed. Also, directly calling
784 dict.__hash__ and list.__hash__ now raises the same TypeError
785 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000786
Guido van Rossumd331cb52001-12-05 19:46:42 +0000787- New-style objects now support deleting their __dict__. This is for
788 all intents and purposes equivalent to assigning a brand new empty
789 dictionary, but saves space if the object is not used further.
790
Tim Petersb3c9af12001-11-17 00:21:57 +0000791Core and builtins
792
Tim Peters3caca232001-12-06 06:23:26 +0000793- -Qnew now works as documented in PEP 238: when -Qnew is passed on
794 the command line, all occurrences of "/" use true division instead
795 of classic division. See the PEP for details. Note that "all"
796 means all instances in library and 3rd-party modules, as well as in
797 your own code. As the PEP says, -Qnew is intended for use only in
798 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000799 Note that test_coercion.py in the standard Python test suite fails
800 under -Qnew; this is expected, and won't be repaired until true
801 division becomes the default (in the meantime, test_coercion is
802 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000803
Fred Drake6c01e252001-12-14 17:08:12 +0000804- complex() now only allows the first argument to be a string
805 argument, and raises TypeError if either the second arg is a string
806 or if the second arg is specified when the first is a string.
807
Tim Petersb3c9af12001-11-17 00:21:57 +0000808Extension modules
809
Martin v. Löwis560da622001-11-24 09:24:51 +0000810- gc.get_referents was renamed to gc.get_referrers.
811
Tim Petersb3c9af12001-11-17 00:21:57 +0000812Library
813
Tim Peters25059d32001-12-07 20:35:43 +0000814- Functions in the os.spawn() family now release the global interpreter
815 lock around calling the platform spawn. They should always have done
816 this, but did not before 2.2c1. Multithreaded programs calling
817 an os.spawn function with P_WAIT will no longer block all Python threads
818 until the spawned program completes. It's possible that some programs
819 relies on blocking, although more likely by accident than by design.
820
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000821- webbrowser defaults to netscape.exe on OS/2 now.
822
Martin v. Löwis652e1912001-11-25 14:50:56 +0000823- Tix.ResizeHandle exposes detach_widget, hide, and show.
824
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000825- The charset alias windows_1252 has been added.
826
Barry Warsaw06557452001-12-14 20:47:12 +0000827- types.StringTypes is a tuple containing the defined string types;
828 usually this will be (str, unicode), but if Python was compiled
829 without Unicode support it will be just (str,).
830
831- The pulldom and minidom modules were synchronized to PyXML.
832
Tim Petersb3c9af12001-11-17 00:21:57 +0000833Tools/Demos
834
Barry Warsaw06557452001-12-14 20:47:12 +0000835- A new script called Tools/scripts/google.py was added, which fires
836 off a search on Google.
837
Tim Petersb3c9af12001-11-17 00:21:57 +0000838Build
839
Barry Warsaw06557452001-12-14 20:47:12 +0000840- Note that release builds of Python should arrange to define the
841 preprocessor symbol NDEBUG on the command line (or equivalent).
842 In the 2.2 pre-release series we tried to define this by magic in
843 Python.h instead, but it proved to cause problems for extension
844 authors. The Unix, Windows and Mac builds now all define NDEBUG in
845 release builds via cmdline (or equivalent) instead. Ports to
846 other platforms should do likewise.
847
Jack Jansen1999ef42001-12-06 21:47:20 +0000848- It is no longer necessary to use --with-suffix when building on a
849 case-insensitive file system (such as Mac OS X HFS+). In the build
850 directory an extension is used, but not in the installed python.
851
Tim Petersb3c9af12001-11-17 00:21:57 +0000852C API
853
Tim Petersf582b822001-12-11 18:51:08 +0000854- New function PyDict_MergeFromSeq2() exposes the builtin dict
855 constructor's logic for updating a dictionary from an iterable object
856 producing key-value pairs.
857
Tim Peterscffed4b2001-11-29 03:26:37 +0000858- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000859 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000860 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
861 dump core in some bad cases. This has been repaired. As a result,
862 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
863 previously went unchallenged.
864
Tim Petersb3c9af12001-11-17 00:21:57 +0000865New platforms
866
867Tests
868
869Windows
870
871Mac
872
Jack Jansenffa260f2001-12-06 21:14:00 +0000873- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
874 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000875
Barry Warsaw06557452001-12-14 20:47:12 +0000876- Changed logic for finding python home in Mac OS X framework Pythons.
877 Now sys.executable points to the executable again, in stead of to
878 the shared library. The latter is used only for locating the python
879 home.
880
881
Tim Peters84362bc2001-10-19 17:55:30 +0000882What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000883Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000884===========================
885
886Type/class unification and new-style classes
887
Guido van Rossum3d27df02001-11-15 20:27:54 +0000888- Multiple inheritance mixing new-style and classic classes in the
889 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000890
891 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000892 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000893
894 The MRO (method resolution order) for each base class is respected
895 according to its kind, but the MRO for the derived class is computed
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000896 using new-style MRO rules if any base class is a new-style class.
Tim Peters76f7fe32001-11-15 20:02:21 +0000897 This needs to be documented.
898
Tim Petersa427a2b2001-10-29 22:25:45 +0000899- The new builtin dictionary() constructor, and dictionary type, have
900 been renamed to dict. This reflects a decade of common usage.
901
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000902- dict() now accepts an iterable object producing 2-sequences. For
903 example, dict(d.items()) == d for any dictionary d. The argument,
904 and the elements of the argument, can be any iterable objects.
905
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000906- New-style classes can now have a __del__ method, which is called
907 when the instance is deleted (just like for classic classes).
908
Guido van Rossum12d955c2001-10-26 14:56:06 +0000909- Assignment to object.__dict__ is now possible, for objects that are
910 instances of new-style classes that have a __dict__ (unless the base
911 class forbids it).
912
Guido van Rossumc8e56452001-10-22 00:43:43 +0000913- Methods of built-in types now properly check for keyword arguments
914 (formerly these were silently ignored). The only built-in methods
915 that take keyword arguments are __call__, __init__ and __new__.
916
Guido van Rossum86443212001-10-27 22:28:54 +0000917- The socket function has been converted to a type; see below.
918
Tim Peters84362bc2001-10-19 17:55:30 +0000919Core and builtins
920
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000921- Assignment to __debug__ raises SyntaxError at compile-time. This
922 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000923 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000924
Guido van Rossum12d955c2001-10-26 14:56:06 +0000925- Clarified the error messages for unsupported operands to an operator
926 (like 1 + '').
927
Tim Peters84362bc2001-10-19 17:55:30 +0000928Extension modules
929
Tim Peters5ebfd362001-11-13 23:11:19 +0000930- mmap has a new keyword argument, "access", allowing a uniform way for
931 both Windows and Unix users to create read-only, write-through and
932 copy-on-write memory mappings. This was previously possible only on
933 Unix. A new keyword argument was required to support this in a
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000934 uniform way because the mmap() signatures had diverged across
Tim Peters5ebfd362001-11-13 23:11:19 +0000935 platforms. Thanks to Jay T Miller for repairing this!
936
Tim Peters169ded02001-11-03 19:57:21 +0000937- By default, the gc.garbage list now contains only those instances in
938 unreachable cycles that have __del__ methods; in 2.1 it contained all
939 instances in unreachable cycles. "Instances" here has been generalized
940 to include instances of both new-style and old-style classes.
941
Guido van Rossum12d955c2001-10-26 14:56:06 +0000942- The socket module defines a new method for socket objects,
943 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000944 send() until all data has been sent. Also, the socket function has
945 been converted to a subclassable type, like list and tuple (etc.)
946 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000947
948- Various bugfixes to the curses module. There is now a test suite
949 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000950
Guido van Rossum692adf12001-10-30 03:03:03 +0000951- binascii.b2a_base64 no longer places an arbitrary restriction of 57
952 bytes on its input.
953
Tim Peters84362bc2001-10-19 17:55:30 +0000954Library
955
Tim Peters5ebfd362001-11-13 23:11:19 +0000956- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000957 convenience function.
958
Tim Peters75335872001-11-03 19:35:43 +0000959- Symbolic group names in regular expressions must be unique. For
960 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
961 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000962 Python 2.2 detects this error at regexp compilation time;
963 previously, the error went undetected, and results were
964 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
965 pattern.subn() methods have been rewritten in C. Also, an
966 experimental function/method finditer() has been added, which works
967 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000968
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000969- Tix exposes more commands through the classes DirSelectBox,
970 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
971 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
972 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
973
Tim Peters98791af2001-10-23 01:59:54 +0000974- Traceback objects are now scanned by cyclic garbage collection, so
975 cycles created by casual use of sys.exc_info() no longer cause
976 permanent memory leaks (provided garbage collection is enabled).
977
Guido van Rossum49192142001-10-24 20:51:44 +0000978- os.extsep -- a new variable needed by the RISCOS support. It is the
979 separator used by extensions, and is '.' on all platforms except
980 RISCOS, where it is '/'. There is no need to use this variable
981 unless you have a masochistic desire to port your code to RISCOS.
982
Barry Warsaw012852b2001-11-16 16:17:27 +0000983- mimetypes.py has optional support for non-standard, but commonly
984 found types. guess_type() and guess_extension() now accept an
985 optional `strict' flag, defaulting to true, which controls whether
986 recognize non-standard types or not. A few non-standard types we
987 know about have been added. Also, when run as a script, there are
988 new -l and -e options.
989
990- statcache is now deprecated.
991
992- email.Utils.formatdate() now produces the preferred RFC 2822 style
993 dates with numeric timezones (it used to produce obsolete dates
994 hard coded to "GMT" timezone). An optional `localtime' flag is
995 added to produce dates in the local timezone, with daylight savings
996 time properly taken into account.
997
998- In pickle and cPickle, instead of masking errors in load() by
999 transforming them into SystemError, we let the original exception
1000 propagate out. Also, implement support for __safe_for_unpickling__
1001 in pickle, as it already was supported in cPickle.
1002
Tim Peters84362bc2001-10-19 17:55:30 +00001003Tools/Demos
1004
1005Build
1006
Barry Warsaw012852b2001-11-16 16:17:27 +00001007- The dbm module is built using libdb1 if available. The bsddb module
1008 is built with libdb3 if available.
1009
1010- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
1011
Tim Peters84362bc2001-10-19 17:55:30 +00001012C API
1013
Tim Peters1fc240e2001-10-26 05:06:50 +00001014- New function PySequence_Fast_GET_SIZE() returns the size of a non-
1015 NULL result from PySequence_Fast(), more quickly than calling
1016 PySequence_Size().
1017
Barry Warsaw012852b2001-11-16 16:17:27 +00001018- New argument unpacking function PyArg_UnpackTuple() added.
1019
1020- New functions PyObject_CallFunctionObjArgs() and
1021 PyObject_CallMethodObjArgs() have been added to make it more
1022 convenient and efficient to call functions and methods from C.
1023
1024- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
1025 possible that this will propagate errors it didn't before.
1026
1027- New function PyObject_CheckReadBuffer(), which returns true if its
1028 argument supports the single-segment readable buffer interface.
1029
Tim Peters84362bc2001-10-19 17:55:30 +00001030New platforms
1031
Guido van Rossum86443212001-10-27 22:28:54 +00001032- We've finally confirmed that this release builds on HP-UX 11.00,
1033 *with* threads, and passes the test suite.
1034
Tim Peters7a33d8b2001-11-05 02:51:07 +00001035- Thanks to a series of patches from Michael Muller, Python may build
1036 again under OS/2 Visual Age C++.
1037
Guido van Rossum49192142001-10-24 20:51:44 +00001038- Updated RISCOS port by Dietmar Schwertberger.
1039
Tim Peters84362bc2001-10-19 17:55:30 +00001040Tests
1041
Andrew M. Kuchling15e03532001-10-22 16:37:10 +00001042- Added a test script for the curses module. It isn't run automatically;
1043 regrtest.py must be run with '-u curses' to enable it.
1044
Tim Peters84362bc2001-10-19 17:55:30 +00001045Windows
1046
Barry Warsaw012852b2001-11-16 16:17:27 +00001047Mac
1048
1049- PythonScript has been moved to unsupported and is slated to be
1050 removed completely in the next release.
1051
1052- It should now be possible to build applets that work on both OS9 and
1053 OSX.
1054
1055- The core is now linked with CoreServices not Carbon; as a side
1056 result, default 8bit encoding on OSX is now ASCII.
1057
1058- Python should now build on OSX 10.1.1
1059
Tim Peters84362bc2001-10-19 17:55:30 +00001060
Tim Petersabf925f2001-09-28 21:53:42 +00001061What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +00001062Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +00001063===========================
1064
1065Type/class unification and new-style classes
1066
Guido van Rossum687ae002001-10-15 22:03:32 +00001067- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001068 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +00001069 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001070 remains: the __dict__ of a new-style class is a read-only proxy; you
1071 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +00001072 __defined__ attribute of new-style types no longer exists, for lack
1073 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001074 future a __cache__ may be resurrected with a similar function, if I
1075 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +00001076
Tim Peters1c9ca872001-10-04 06:43:12 +00001077- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
1078 always returned None, even when there was a class docstring).
1079
1080- doctest now finds and runs docstrings attached to new-style classes,
1081 class methods, static methods, and properties.
1082
Guido van Rossum9074ef62001-10-16 21:34:49 +00001083Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +00001084
Guido van Rossuma8bcf802001-10-15 15:53:58 +00001085- A very subtle syntactical pitfall in list comprehensions was fixed.
1086 For example: [a+b for a in 'abc', for b in 'def']. The comma in
1087 this example is a mistake. Previously, this would silently let 'a'
1088 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
1089 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
1090 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
1091 Note that [a for a in <singleton>] is a convoluted way to say
1092 [<singleton>] anyway, so it's not like any expressiveness is lost.
1093
Guido van Rossum9074ef62001-10-16 21:34:49 +00001094- getattr(obj, name, default) now only catches AttributeError, as
1095 documented, rather than returning the default value for all
1096 exceptions (which could mask bugs in a __getattr__ hook, for
1097 example).
1098
Fred Drakecb7a6b52001-10-22 18:41:51 +00001099- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +00001100 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001101 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +00001102 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +00001103
Guido van Rossum1c486092001-10-19 02:05:35 +00001104- unicode(obj) now behaves more like str(obj), accepting arbitrary
1105 objects, and calling a __unicode__ method if it exists.
1106 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +00001107 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +00001108
Barry Warsawf6fb1712001-10-19 05:35:40 +00001109- isinstance() now allows any object as the first argument and a
1110 class, a type or something with a __bases__ tuple attribute for the
1111 second argument. The second argument may also be a tuple of a
1112 class, type, or something with __bases__, in which case isinstance()
1113 will return true if the first argument is an instance of any of the
1114 things contained in the second argument tuple. E.g.
1115
1116 isinstance(x, (A, B))
1117
1118 returns true if x is an instance of A or B.
1119
Guido van Rossum9074ef62001-10-16 21:34:49 +00001120Extension modules
1121
1122- thread.start_new_thread() now returns the thread ID (previously None).
1123
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001124- binascii has now two quopri support functions, a2b_qp and b2a_qp.
1125
Guido van Rossumc524d952001-10-19 01:31:59 +00001126- readline now supports setting the startup_hook and the
1127 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +00001128
Guido van Rossumc524d952001-10-19 01:31:59 +00001129- os and posix supports chroot(), setgroups() and unsetenv() where
1130 available. The stat(), fstat(), statvfs() and fstatvfs() functions
1131 now return "pseudo-sequences" -- the various fields can now be
1132 accessed as attributes (e.g. os.stat("/").st_mtime) but for
1133 backwards compatibility they also behave as a fixed-length sequence.
1134 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +00001135 attributes.
1136
1137- time: localtime(), gmtime() and strptime() now return a
1138 pseudo-sequence similar to the os.stat() return value, with
1139 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +00001140
Guido van Rossum9074ef62001-10-16 21:34:49 +00001141- Decompression objects in the zlib module now accept an optional
1142 second parameter to decompress() that specifies the maximum amount
1143 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +00001144
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001145- optional SSL support in the socket module now exports OpenSSL
1146 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
1147 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +00001148 automatically seed its PRNG. Also, the keyfile and certfile
1149 arguments to socket.ssl() are now optional.
1150
1151- posixmodule (and by extension, the os module on POSIX platforms) now
1152 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001153
Guido van Rossum9074ef62001-10-16 21:34:49 +00001154Library
Guido van Rossum3c288632001-10-16 21:13:49 +00001155
Tim Peters7402f792001-10-02 03:53:41 +00001156- doctest now excludes functions and classes not defined by the module
1157 being tested, thanks to Tim Hochberg.
1158
Fred Drakecb7a6b52001-10-22 18:41:51 +00001159- HotShot, a new profiler implemented using a C-based callback, has
1160 been added. This substantially reduces the overhead of profiling,
1161 but it is still quite preliminary. Support modules and
1162 documentation will be added in upcoming releases (before 2.2 final).
1163
Guido van Rossumc4b09b42001-10-04 10:19:00 +00001164- profile now produces correct output in situations where an exception
1165 raised in Python is cleared by C code (e.g. hasattr()). This used
1166 to cause wrong output, including spurious claims of recursive
1167 functions and attribution of time spent to the wrong function.
1168
Tim Peters0a1fc4e2001-10-07 03:12:08 +00001169 The code and documentation for the derived OldProfile and HotProfile
1170 profiling classes was removed. The code hasn't worked for years (if
1171 you tried to use them, they raised exceptions). OldProfile
1172 intended to reproduce the behavior of the profiler Python used more
1173 than 7 years ago, and isn't interesting anymore. HotProfile intended
1174 to provide a faster profiler (but producing less information), and
1175 that's a worthy goal we intend to meet via a different approach (but
1176 without losing information).
1177
Tim Peterscce092d2001-10-09 05:31:56 +00001178- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +00001179 a much better system-specific calibration constant. The constant can
1180 now be specified in an instance constructor, or as a Profile class or
1181 instance variable, instead of by editing profile.py's source code.
1182 Calibration must still be done manually (see the docs for the profile
1183 module).
1184
1185 Note that Profile.calibrate() must be overriden by subclasses.
1186 Improving the accuracy required exploiting detailed knowledge of
1187 profiler internals; the earlier method abstracted away the details
1188 and measured a simplified model instead, but consequently computed
1189 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +00001190
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001191- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +00001192 which indicates whether output is intended for the header 'Q'
1193 encoding.
1194
Guido van Rossuma5343cc2001-10-18 18:02:07 +00001195- The SocketServer.ThreadingMixIn class now closes the request after
1196 finish_request() returns. (Not when it errors out though.)
1197
Barry Warsawf6fb1712001-10-19 05:35:40 +00001198- The nntplib module's NNTP.body() method has grown a `file' argument
1199 to allow saving the message body to a file.
1200
1201- The email package has added a class email.Parser.HeaderParser which
1202 only parses headers and does not recurse into the message's body.
1203 Also, the module/class MIMEAudio has been added for representing
1204 audio data (contributed by Anthony Baxter).
1205
1206- ftplib should be able to handle files > 2GB.
1207
1208- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
1209 ON, and OFF.
1210
Fred Drakecb7a6b52001-10-22 18:41:51 +00001211- xml.dom.minidom NodeList objects now support the length attribute
1212 and item() method as required by the DOM specifications.
1213
Guido van Rossumed554f62001-10-02 23:15:37 +00001214Tools/Demos
1215
1216- Demo/dns was removed. It no longer serves any purpose; a package
1217 derived from it is now maintained by Anthony Baxter, see
1218 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +00001219
Barry Warsawf6fb1712001-10-19 05:35:40 +00001220- The freeze tool has been made more robust, and two new options have
1221 been added: -X and -E.
1222
Tim Petersabf925f2001-09-28 21:53:42 +00001223Build
1224
Barry Warsawf6fb1712001-10-19 05:35:40 +00001225- configure will use CXX in LINKCC if CXX is used to build main() and
1226 the system requires to link a C++ main using the C++ compiler.
1227
Tim Petersabf925f2001-09-28 21:53:42 +00001228C API
1229
Guido van Rossum6c4bce32001-10-18 19:20:25 +00001230- The documentation for the tp_compare slot is updated to require that
1231 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
1232 not correct. This is not yet enforced but will be enforced in
1233 Python 2.3; even later, we may use -2 to indicate errors and +2 for
1234 "NotImplemented". Right now, -1 should be used for an error return.
1235
Tim Petersd38b1c72001-09-30 05:09:37 +00001236- PyLong_AsLongLong() now accepts int (as well as long) arguments.
1237 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
1238 as long) arguments.
1239
Guido van Rossum3c288632001-10-16 21:13:49 +00001240- PyThread_start_new_thread() now returns a long int giving the thread
1241 ID, if one can be calculated; it returns -1 for error, 0 if no
1242 thread ID is calculated (this is an incompatible change, but only
1243 the thread module used this API). This code has only really been
1244 tested on Linux and Windows; other platforms please beware (and
1245 report any bugs or strange behavior).
1246
Guido van Rossum1c486092001-10-19 02:05:35 +00001247- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
1248 input.
1249
Tim Petersabf925f2001-09-28 21:53:42 +00001250New platforms
1251
1252Tests
1253
1254Windows
1255
Tim Peters04cf1d32001-10-09 22:39:40 +00001256- Installer: If you install IDLE, and don't disable file-extension
1257 registration, a new "Edit with IDLE" context (right-click) menu entry
1258 is created for .py and .pyw files.
1259
Tim Peters1ce3cf72001-10-01 17:58:40 +00001260- The signal module now supports SIGBREAK on Windows, thanks to Steven
1261 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
1262 action remains to call Win32 ExitProcess(). This can be changed via
1263 signal.signal(). For example:
1264
1265 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
1266 # (SIGINT) behavior.
1267 import signal
1268 signal.signal(signal.SIGBREAK,
1269 signal.default_int_handler)
1270
1271 try:
1272 while 1:
1273 pass
1274 except KeyboardInterrupt:
1275 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
1276 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
1277 # program without the possibility for any Python-level cleanup).
1278 print "Clean exit"
1279
Tim Petersabf925f2001-09-28 21:53:42 +00001280
Tim Petersb07352e2001-09-08 01:25:47 +00001281What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001282Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +00001283===========================
1284
Guido van Rossum808eea72001-09-25 04:15:41 +00001285Type/class unification and new-style classes
1286
1287- pydoc and inspect are now aware of new-style classes;
1288 e.g. help(list) at the interactive prompt now shows proper
1289 documentation for all operations on list objects.
1290
1291- Applications using Jim Fulton's ExtensionClass module can now safely
1292 be used with Python 2.2. In particular, Zope 2.4.1 now works with
1293 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
1294 examples also work again. It is hoped that Gtk and Boost also work
1295 with 2.2a4 and beyond. (If you can confirm this, please write
1296 webmaster@python.org; if there are still problems, please open a bug
1297 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +00001298
Tim Peters66c1a522001-09-24 21:17:50 +00001299- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001300 These map to read-only attributes 'fget', 'fset', 'fdel', and '__doc__'
Tim Peters66c1a522001-09-24 21:17:50 +00001301 in the constructed property object. fget, fset and fdel weren't
1302 discoverable from Python in 2.2a3. __doc__ is new, and allows to
1303 associate a docstring with a property.
1304
Guido van Rossum808eea72001-09-25 04:15:41 +00001305- Comparison overloading is now more completely implemented. For
1306 example, a str subclass instance can properly be compared to a str
1307 instance, and it can properly overload comparison. Ditto for most
1308 other built-in object types.
1309
1310- The repr() of new-style classes has changed; instead of <type
1311 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
1312 *except* for built-in types, which are still rendered as <type
1313 'Foo'> (to avoid upsetting existing code that might parse or
1314 otherwise rely on repr() of certain type objects).
1315
1316- The repr() of new-style objects is now always <Foo object at XXX>;
1317 previously, it was sometimes <Foo instance at XXX>.
1318
1319- For new-style classes, what was previously called __getattr__ is now
1320 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001321 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +00001322 one in classic classes is defined which is called only if regular
1323 attribute access raises AttributeError; to catch *all* attribute
1324 access, you can use __getattribute__ (for new-style classes). If
1325 both are defined, __getattribute__ is called first, and if it raises
1326 AttributeError, __getattr__ is called.
1327
1328- The __class__ attribute of new-style objects can be assigned to.
1329 The new class must have the same C-level object layout as the old
1330 class.
1331
1332- The builtin file type can be subclassed now. In the usual pattern,
1333 "file" is the name of the builtin type, and file() is a new builtin
1334 constructor, with the same signature as the builtin open() function.
1335 file() is now the preferred way to open a file.
1336
1337- Previously, __new__ would only see sequential arguments passed to
1338 the type in a constructor call; __init__ would see both sequential
1339 and keyword arguments. This made no sense whatsoever any more, so
1340 now both __new__ and __init__ see all arguments.
1341
1342- Previously, hash() applied to an instance of a subclass of str or
1343 unicode always returned 0. This has been repaired.
1344
1345- Previously, an operation on an instance of a subclass of an
1346 immutable type (int, long, float, complex, tuple, str, unicode),
1347 where the subtype didn't override the operation (and so the
1348 operation was handled by the builtin type), could return that
1349 instance instead a value of the base type. For example, if s was of
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001350 a str subclass type, s[:] returned s as-is. Now it returns a str
Guido van Rossum808eea72001-09-25 04:15:41 +00001351 with the same value as s.
1352
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001353- Provisional support for pickling new-style objects has been added.
1354
Guido van Rossum808eea72001-09-25 04:15:41 +00001355Core
1356
Tim Peters2c9aa5e2001-09-23 04:06:05 +00001357- file.writelines() now accepts any iterable object producing strings.
1358
Marc-André Lemburgaefd7662001-09-20 12:59:37 +00001359- PyUnicode_FromEncodedObject() now works very much like
1360 PyObject_Str(obj) in that it tries to use __str__/tp_str
1361 on the object if the object is not a string or buffer. This
1362 makes unicode() behave like str() when applied to non-string/buffer
1363 objects.
1364
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001365- PyFile_WriteObject now passes Unicode objects to the file's write
1366 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +00001367 of a print statement must support Unicode objects, i.e. they must
1368 at least convert them into ASCII strings.
1369
Guido van Rossum624c8af2001-09-18 15:21:04 +00001370- Thread scheduling on Solaris should be improved; it is no longer
1371 necessary to insert a small sleep at the start of a thread in order
1372 to let other runnable threads be scheduled.
1373
Tim Petersb07352e2001-09-08 01:25:47 +00001374Library
1375
Marc-André Lemburgbf990172001-09-27 14:17:33 +00001376- StringIO.StringIO instances and cStringIO.StringIO instances support
1377 read character buffer compatible objects for their .write() methods.
1378 These objects are converted to strings and then handled as such
1379 by the instances.
1380
Barry Warsaw2f600732001-09-24 04:28:10 +00001381- The "email" package has been added. This is basically a port of the
1382 mimelib package <http://sf.net/projects/mimelib> with API changes
1383 and some implementations updated to use iterators and generators.
1384
Tim Peters8a9c2842001-09-22 21:30:22 +00001385- difflib.ndiff() and difflib.Differ.compare() are generators now. This
1386 restores the ability of Tools/scripts/ndiff.py to start producing output
1387 before the entire comparison is complete.
1388
Barry Warsaw58b072d2001-09-22 04:44:21 +00001389- StringIO.StringIO instances and cStringIO.StringIO instances support
1390 iteration just like file objects (i.e. their .readline() method is
1391 called for each iteration until it returns an empty string).
1392
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +00001393- The codecs module has grown four new helper APIs to access
1394 builtin codecs: getencoder(), getdecoder(), getreader(),
1395 getwriter().
1396
Guido van Rossum624c8af2001-09-18 15:21:04 +00001397- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
1398 simplifies writing XML RPC servers.
1399
Barry Warsaw647d5e82001-09-28 17:01:02 +00001400- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +00001401 after interpretation of symbolic links. On non-Unix systems, this
1402 is an alias for os.path.abspath().
1403
Tim Peters16a77ad2001-09-08 04:00:12 +00001404- operator.indexOf() (PySequence_Index() in the C API) now works with any
1405 iterable object.
1406
Guido van Rossum624c8af2001-09-18 15:21:04 +00001407- smtplib now supports various authentication and security features of
1408 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001409
Guido van Rossum624c8af2001-09-18 15:21:04 +00001410- hmac: a new module implementing keyed hashing for message
1411 authentication.
1412
1413- mimetypes now recognizes more extensions and file types. At the
1414 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001415
Guido van Rossum624c8af2001-09-18 15:21:04 +00001416- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001417 Python 2.2 bytecode generation. It has also been promoted from a
1418 Tool to a standard library package. (Tools/compiler still exists as
1419 a sample driver.)
1420
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001421Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +00001422
Tim Petersb07352e2001-09-08 01:25:47 +00001423Build
1424
Guido van Rossum624c8af2001-09-18 15:21:04 +00001425- Large file support (LFS) is now automatic when the platform supports
1426 it; no more manual configuration tweaks are needed. On Linux, at
1427 least, it's possible to have a system whose C library supports large
1428 files but whose kernel doesn't; in this case, large file support is
1429 still enabled but doesn't do you any good unless you upgrade your
1430 kernel or share your Python executable with another system whose
1431 kernel has large file support.
1432
1433- The configure script now supplies plausible defaults in a
1434 cross-compilation environment. This doesn't mean that the supplied
1435 values are always correct, or that cross-compilation now works
1436 flawlessly -- but it's a first step (and it shuts up most of
1437 autoconf's warnings about AC_TRY_RUN).
1438
1439- The Unix build is now a bit less chatty, courtesy of the parser
1440 generator. The build is completely silent (except for errors) when
1441 using "make -s", thanks to a -q option to setup.py.
1442
Tim Petersb07352e2001-09-08 01:25:47 +00001443C API
1444
Guido van Rossum624c8af2001-09-18 15:21:04 +00001445- The "structmember" API now supports some new flag bits to deny read
1446 and/or write access to attributes in restricted execution mode.
1447
Tim Petersb07352e2001-09-08 01:25:47 +00001448New platforms
1449
Guido van Rossum624c8af2001-09-18 15:21:04 +00001450- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1451 (http://familiar.handhelds.org).
1452
Tim Petersb07352e2001-09-08 01:25:47 +00001453Tests
1454
Tim Peters8a9c2842001-09-22 21:30:22 +00001455- The "classic" standard tests, which work by comparing stdout to
1456 an expected-output file under Lib/test/output/, no longer stop at
1457 the first mismatch. Instead the test is run to completion, and a
1458 variant of ndiff-style comparison is used to report all differences.
1459 This is much easier to understand than the previous style of reporting.
1460
1461- The unittest-based standard tests now use regrtest's test_main()
1462 convention, instead of running as a side-effect of merely being
1463 imported. This allows these tests to be run in more natural and
1464 flexible ways as unittests, outside the regrtest framework.
1465
1466- regrtest.py is much better integrated with unittest and doctest now,
1467 especially in regard to reporting errors.
1468
Tim Petersb07352e2001-09-08 01:25:47 +00001469Windows
1470
Guido van Rossum624c8af2001-09-18 15:21:04 +00001471- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001472 that support it (NTFS under Windows 2000). See "What's New in
1473 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001474
Tim Petersb07352e2001-09-08 01:25:47 +00001475
Tim Petersedc99312001-08-22 21:36:50 +00001476What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001477Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001478===========================
1479
1480Core
1481
Tim Peters9fffa3e2001-09-04 05:14:19 +00001482- Conversion of long to float now raises OverflowError if the long is too
1483 big to represent as a C double.
1484
Tim Peters32f453e2001-09-03 08:35:41 +00001485- The 3-argument builtin pow() no longer allows a third non-None argument
1486 if either of the first two arguments is a float, or if both are of
1487 integer types and the second argument is negative (in which latter case
1488 the arguments are converted to float, so this is really the same
1489 restriction).
1490
Tim Peters5d2b77c2001-09-03 05:47:38 +00001491- The builtin dir() now returns more information, and sometimes much
1492 more, generally naming all attributes of an object, and all attributes
1493 reachable from the object via its class, and from its class's base
1494 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1495 an empty list. In 2.2a3,
1496
1497 >>> dir([])
1498 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1499 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1500 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1501 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1502 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1503 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1504 'reverse', 'sort']
1505
1506 dir(module) continues to return only the module's attributes, though.
1507
Tim Petersbdee63f2001-09-02 03:40:59 +00001508- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001509 than raising OverflowError. This is a partial implementation of PEP
1510 237. You can use -Wdefault::OverflowWarning to enable a warning for
1511 this situation, and -Werror::OverflowWarning to revert to the old
1512 OverflowError exception.
1513
Guido van Rossum61c345f2001-09-04 03:26:15 +00001514- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001515 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001516 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1517 -Qold, meaning the / operator has its classic meaning and no
1518 warnings are issued. Using -Qwarn issues a run-time warning about
1519 all uses of classic division for int and long arguments; -Qwarnall
1520 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001521 (for use with fixdiv.py).
1522 [Note: the remainder of this paragraph (preserved below) became
1523 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1524 <obsolete>
1525 Using -Qnew is questionable; it turns on new division by default, but
1526 only in the __main__ module. You can usefully combine -Qwarn or
1527 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1528 warns about classic division everywhere else.
1529 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001530
Tim Petersbdee63f2001-09-02 03:40:59 +00001531- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001532 long, float, str, unicode, and tuple. (The types complex, list and
1533 dictionary can also be subclassed; this was introduced earlier.)
1534 Note that restrictions apply when subclassing immutable built-in
1535 types: you can only affect the value of the instance by overloading
1536 __new__. You can add mutable attributes, and the subclass instances
1537 will have a __dict__ attribute, but you cannot change the "value"
1538 (as implemented by the base class) of an immutable subclass instance
1539 once it is created.
1540
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001541- The dictionary constructor now takes an optional argument, a
1542 mapping-like object, and initializes the dictionary from its
1543 (key, value) pairs.
1544
Tim Petersbdee63f2001-09-02 03:40:59 +00001545- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001546 "cooperative super calls" in a multiple inheritance setting. For an
1547 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1548
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001549- A new built-in type, property, has been added. This enables the
1550 creation of "properties". These are attributes implemented by
1551 getter and setter functions (or only one of these for read-only or
1552 write-only attributes), without the need to override __getattr__.
1553 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001554
Tim Petersbdee63f2001-09-02 03:40:59 +00001555- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001556 liberalized, to allow leading zeroes. Examples of literals now
1557 legal that were SyntaxErrors before:
1558
1559 00.0 0e3 0100j 07.5 00000000000000000008.
1560
Tim Petersbdee63f2001-09-02 03:40:59 +00001561- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001562 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1563
Tim Petersedc99312001-08-22 21:36:50 +00001564Library
1565
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001566- telnetlib includes symbolic names for the options, and support for
1567 setting an option negotiation callback.
1568
Tim Petersa40c7932001-09-05 22:36:56 +00001569- The new C standard no longer requires that math libraries set errno to
1570 ERANGE on overflow. For platform libraries that exploit this new
1571 freedom, Python's overflow-checking was wholly broken. A new overflow-
1572 checking scheme attempts to repair that, but may not be reliable on all
1573 platforms (C doesn't seem to provide anything both useful and portable
1574 in this area anymore).
1575
Martin v. Löwis44f86962001-09-05 13:44:54 +00001576- Asynchronous timeout actions are available through the new class
1577 threading.Timer.
1578
Tim Peters78526162001-09-05 00:53:45 +00001579- math.log and math.log10 now return sensible results for even huge
1580 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1581
Tim Petersbdee63f2001-09-02 03:40:59 +00001582- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001583 currently held. See the docs for the imp module.
1584
Tim Petersbdee63f2001-09-02 03:40:59 +00001585- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001586 dumps containing ints written on platforms where Python ints are 8 bytes.
1587 When read on a box where Python ints are 4 bytes, such values are
1588 converted to Python longs.
1589
Tim Petersbdee63f2001-09-02 03:40:59 +00001590- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001591 code objects is no longer allowed. This plugs a security hole.
1592
Steve Purcell6091cd62001-09-06 16:05:17 +00001593- unittest.TestResult instances no longer store references to tracebacks
1594 generated by test failures. This prevents unexpected dangling references
1595 to objects that should be garbage collected between tests.
1596
Tim Petersedc99312001-08-22 21:36:50 +00001597Tools
1598
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001599- Tools/scripts/fixdiv.py has been added which can be used to fix
1600 division operators as per PEP 238.
1601
Tim Petersedc99312001-08-22 21:36:50 +00001602Build
1603
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001604- If you are an adventurous person using Mac OS X you may want to look at
1605 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1606 application, which can be used for experimenting with Carbon or Cocoa.
1607 Discussion of this on pythonmac-sig, please.
1608
Tim Peters7eea37e2001-09-04 22:08:56 +00001609C API
1610
1611- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001612
Tim Peters9fffa3e2001-09-04 05:14:19 +00001613- Note that PyLong_AsDouble can fail! This has always been true, but no
1614 callers checked for it. It's more likely to fail now, because overflow
1615 errors are properly detected now. The proper way to check:
1616
1617 double x = PyLong_AsDouble(some_long_object);
1618 if (x == -1.0 && PyErr_Occurred()) {
1619 /* The conversion failed. */
1620 }
1621
Tim Petersbdee63f2001-09-02 03:40:59 +00001622- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001623 compile but will not participate in GC. To upgrade an extension
1624 module:
1625
1626 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001627
Neil Schemenauer4042c692001-08-30 15:38:01 +00001628 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1629 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001630
Neil Schemenauer4042c692001-08-30 15:38:01 +00001631 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1632 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001633
Neil Schemenauer4042c692001-08-30 15:38:01 +00001634 - remove PyGC_HEAD_SIZE from object size calculations
1635
1636 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1637
Tim Petersbdee63f2001-09-02 03:40:59 +00001638- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001639 These can be used safely to construct string objects from a
1640 sprintf-style format string (similar to the format string supported
1641 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001642
Tim Petersedc99312001-08-22 21:36:50 +00001643New platforms
1644
Tim Petersb7da0902001-09-02 23:01:43 +00001645- Stephen Hansen contributed patches sufficient to get a clean compile
1646 under Borland C (Windows), but he reports problems running it and ran
1647 out of time to complete the port. Volunteers? Expect a MemoryError
1648 when importing the types module; this is probably shallow, and
1649 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001650
Tim Petersedc99312001-08-22 21:36:50 +00001651Tests
1652
1653Windows
1654
Tim Peters6e13a562001-09-06 00:32:15 +00001655- Large file support is now enabled on Win32 platforms as well as on
1656 Win64. This means that, for example, you can use f.tell() and f.seek()
1657 to manipulate files larger than 2 gigabytes (provided you have enough
1658 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001659 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1660 filesize limit, and large file support makes no difference there.
1661 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1662 NTFS has no practical limit on file size, and files of any size can be
1663 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001664
Tim Petersbdee63f2001-09-02 03:40:59 +00001665- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001666 points to command.com (patch from Brian Quinlan).
1667
Tim Petersedc99312001-08-22 21:36:50 +00001668
Tim Peters20f51a72001-07-21 02:31:40 +00001669What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001670Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001671===========================
1672
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001673Build
1674
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001675- Tim Peters developed a brand new Windows installer using Wise 8.1,
1676 generously donated to us by Wise Solutions.
1677
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001678- configure supports a new option --enable-unicode, with the values
1679 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1680 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001681
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001682- A new configure option --enable-framework builds a Mac OS X framework,
1683 which "make frameworkinstall" will install. This provides a starting
1684 point for more mac-like functionality, join pythonmac-sig@python.org
1685 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001686
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001687- The NeXT platform is no longer supported.
1688
1689- The `new' module is now statically linked.
1690
Tim Peters0afb6092001-08-15 06:06:44 +00001691Tools
1692
1693- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001694 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001695 the module docstring for details.
1696
Tim Peters20f51a72001-07-21 02:31:40 +00001697Tests
1698
Tim Peters5e824c32001-08-12 22:25:01 +00001699- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001700 platforms, allowing to give clearer test result output. regrtest
1701 also has optional --use/-u switch to run normally disabled tests
1702 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001703
Tim Peters20f51a72001-07-21 02:31:40 +00001704- Several new tests in the standard test suite, with special thanks to
1705 Nick Mathewson.
1706
1707Core
1708
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001709- The floor division operator // has been added as outlined in PEP
1710 238. The / operator still provides classic division (and will until
1711 Python 3.0) unless "from __future__ import division" is included, in
1712 which case the / operator will provide true division. The operator
1713 module provides truediv() and floordiv() functions. Augmented
1714 assignment variants are included, as are the equivalent overloadable
1715 methods and C API methods. See the PEP for a full discussion:
1716 <http://python.sf.net/peps/pep-0238.html>
1717
Tim Peters6cd6a822001-08-17 22:11:27 +00001718- Future statements are now effective in simulated interactive shells
1719 (like IDLE). This should "just work" by magic, but read Michael
1720 Hudson's "Future statements in simulated shells" PEP 264 for full
1721 details: <http://python.sf.net/peps/pep-0264.html>.
1722
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001723- The type/class unification (PEP 252-253) was integrated into the
1724 trunk and is not so tentative any more (the exact specification of
1725 some features is still tentative). A lot of work has done on fixing
1726 bugs and adding robustness and features (performance still has to
1727 come a long way).
1728
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001729- Warnings about a mismatch in the Python API during extension import
1730 now use the Python warning framework (which makes it possible to
1731 write filters for these warnings).
1732
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001733- A function's __dict__ (aka func_dict) will now always be a
1734 dictionary. It used to be possible to delete it or set it to None,
1735 but now both actions raise TypeErrors. It is still legal to set it
1736 to a dictionary object. Getting func.__dict__ before any attributes
1737 have been assigned now returns an empty dictionary instead of None.
1738
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001739- A new command line option, -E, was added which disables the use of
1740 all environment variables, or at least those that are specifically
1741 significant to Python. Usually those have a name starting with
1742 "PYTHON". This was used to fix a problem where the tests fail if
1743 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1744 older distribution.
1745
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001746Library
1747
Tim Peters5e824c32001-08-12 22:25:01 +00001748- New class Differ and new functions ndiff() and restore() in difflib.py.
1749 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001750 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001751
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001752- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1753 value using the minimal quoting required for the value; more
1754 reliable than using xml.sax.saxutils.escape() for attribute values.
1755
1756- Readline completion support for cmd.Cmd was added.
1757
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001758- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1759
1760- Added function threading.BoundedSemaphore()
1761
1762- Added Ka-Ping Yee's cgitb.py module.
1763
1764- The `new' module now exposes the CO_xxx flags.
1765
Martin v. Löwis560da622001-11-24 09:24:51 +00001766- The gc module offers the get_referents function.
1767
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001768New platforms
1769
1770C API
1771
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001772- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1773 which provide a cross-platform implementations for the
1774 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1775 the standard sprintf() and vsprintf() C lib APIs, these versions
1776 apply bounds checking on the used buffer which enhances protection
1777 against buffer overruns.
1778
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001779- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001780 and extensions using different Unicode widths is rendered next to
1781 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001782 will result in an ImportError. Unicode extensions writers must make
1783 sure to check the Unicode width compatibility in their extensions by
1784 using at least one of the mangled Unicode APIs in the extension.
1785
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001786- Two new flags METH_NOARGS and METH_O are available in method definition
1787 tables to simplify implementation of methods with no arguments and a
1788 single untyped argument. Calling such methods is more efficient than
1789 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1790 deprecated.
1791
Tim Petersc1731372001-08-04 08:12:36 +00001792Windows
1793
1794- "import module" now compiles module.pyw if it exists and nothing else
1795 relevant is found.
1796
Tim Peters20f51a72001-07-21 02:31:40 +00001797
Guido van Rossum55a78992001-07-17 17:22:32 +00001798What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001799Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001800===========================
1801
1802Core
Tim Petersa814db52001-05-14 07:05:58 +00001803
Tim Peters6d6c1a32001-08-02 04:15:00 +00001804- TENTATIVELY, a large amount of code implementing much of what's
1805 described in PEP 252 (Making Types Look More Like Classes) and PEP
1806 253 (Subtyping Built-in Types) was added. This will be released
1807 with Python 2.2a1. Documentation will be provided separately
1808 through http://www.python.org/2.2/. The purpose of releasing this
1809 with Python 2.2a1 is to test backwards compatibility. It is
1810 possible, though not likely, that a decision is made not to release
1811 this code as part of 2.2 final, if any serious backwards
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00001812 incompatibilities are found during alpha testing that cannot be
Tim Peters6d6c1a32001-08-02 04:15:00 +00001813 repaired.
1814
Guido van Rossum55a78992001-07-17 17:22:32 +00001815- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001816 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001817 more 'yield' statements. See PEP 255. Since this adds a new
1818 keyword to the language, this feature must be enabled by including a
1819 future statement: "from __future__ import generators" (see PEP 236).
1820 Generators will become a standard feature in a future release
1821 (probably 2.3). Without this future statement, 'yield' remains an
1822 ordinary identifier, but a warning is issued each time it is used.
1823 (These warnings currently don't conform to the warnings framework of
1824 PEP 230; we intend to fix this in 2.2a2.)
1825
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001826- The UTF-16 codec was modified to be more RFC compliant. It will now
1827 only remove BOM characters at the start of the string and then
1828 only if running in native mode (UTF-16-LE and -BE won't remove a
1829 leading BMO character).
1830
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001831- Strings now have a new method .decode() to complement the already
1832 existing .encode() method. These two methods provide direct access
1833 to the corresponding decoders and encoders of the registered codecs.
1834
1835 To enhance the usability of the .encode() method, the special
1836 casing of Unicode object return values was dropped (Unicode objects
1837 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001838
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001839 Both methods will now return whatever the codec in charge of the
1840 requested encoding returns as object, e.g. Unicode codecs will
1841 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1842 will return u"äöü"). This enables codec writer to create codecs
1843 for various simple to use conversions.
1844
1845 New codecs were added to demonstrate these new features (the .encode()
1846 and .decode() columns indicate the type of the returned objects):
1847
1848 Name | .encode() | .decode() | Description
1849 ----------------------------------------------------------------------
1850 uu | string | string | UU codec (e.g. for email)
1851 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001852 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001853 zlib | string | string | zlib compression
1854 hex | string | string | 2-byte hex codec
1855 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1856
Mark Hammond2a0af792001-05-14 03:09:36 +00001857- Some operating systems now support the concept of a default Unicode
1858 encoding for file system operations. Notably, Windows supports 'mbcs'
1859 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001860 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001861 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001862
1863 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001864 functions that return filenames (such as os.listdir()) to return Python
1865 string objects pre-encoded using the default file system encoding for
1866 the platform. As this encoding is likely to be different from Python's
1867 default encoding, converting this name to a Unicode object before passing
1868 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001869 would attempt to use its default encoding (generally ASCII) rather than
1870 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001871
Tim Petersa814db52001-05-14 07:05:58 +00001872 In general, this change simply removes surprises when working with
1873 Unicode and the file system, making these operations work as you expect,
1874 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001875 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001876
Tim Peters61dff2b2001-05-08 15:43:37 +00001877- Float (and complex) literals in source code were evaluated to full
1878 precision only when running from a .py file; the same code loaded from a
1879 .pyc (or .pyo) file could suffer numeric differences starting at about the
1880 12th significant decimal digit. For example, on a machine with IEEE-754
1881 floating arithmetic,
1882
1883 x = 9007199254740992.0
1884 print long(x)
1885
1886 printed 9007199254740992 if run directly from .py, but 9007199254740000
1887 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1888 str(float) instead of repr(float) when building code objects. marshal
1889 now uses repr(float) instead, which should reproduce floats to full
1890 machine precision (assuming the platform C float<->string I/O conversion
1891 functions are of good quality).
1892
1893 This may cause floating-point results to change in some cases, and
1894 usually for the better, but may also cause numerically unstable
1895 algorithms to break.
1896
Tim Peters2f228e72001-05-13 00:19:31 +00001897- The implementation of dicts suffers fewer collisions, which has speed
1898 benefits. However, the order in which dict entries appear in dict.keys(),
1899 dict.values() and dict.items() may differ from previous releases for a
1900 given dict. Nothing is defined about this order, so no program should
1901 rely on it. Nevertheless, it's easy to write test cases that rely on the
1902 order by accident, typically because of printing the str() or repr() of a
1903 dict to an "expected results" file. See Lib/test/test_support.py's new
1904 sortdict(dict) function for a simple way to display a dict in sorted
1905 order.
1906
Tim Peters7a3bfc32001-06-12 01:22:22 +00001907- Many other small changes to dicts were made, resulting in faster
1908 operation along the most common code paths.
1909
Guido van Rossum10315822001-05-01 20:54:30 +00001910- Dictionary objects now support the "in" operator: "x in dict" means
1911 the same as dict.has_key(x).
1912
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001913- The update() method of dictionaries now accepts generic mapping
1914 objects. Specifically the argument object must support the .keys()
1915 and __getitem__() methods. This allows you to say, for example,
1916 {}.update(UserDict())
1917
Guido van Rossum10315822001-05-01 20:54:30 +00001918- Iterators were added; this is a generalized way of providing values
1919 to a for loop. See PEP 234. There's a new built-in function iter()
1920 to return an iterator. There's a new protocol to get the next value
1921 from an iterator using the next() method (in Python) or the
1922 tp_iternext slot (in C). There's a new protocol to get iterators
1923 using the __iter__() method (in Python) or the tp_iter slot (in C).
1924 Iterating (i.e. a for loop) over a dictionary generates its keys.
1925 Iterating over a file generates its lines.
1926
Tim Petersf553f892001-05-01 20:45:31 +00001927- The following functions were generalized to work nicely with iterator
1928 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001929 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001930 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1931 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001932 join() method of strings
1933 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001934 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1935 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001936 right-hand side of assignment statements with multiple targets, such as
1937 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001938
Tim Petersd85e1022001-05-11 21:51:48 +00001939- Accessing module attributes is significantly faster (for example,
1940 random.random or os.path or yourPythonModule.yourAttribute).
1941
Tim Peterse63415e2001-05-08 04:38:29 +00001942- Comparing dictionary objects via == and != is faster, and now works even
1943 if the keys and values don't support comparisons other than ==.
1944
Tim Peters95bf9392001-05-10 08:32:44 +00001945- Comparing dictionaries in ways other than == and != is slower: there were
1946 insecurities in the dict comparison implementation that could cause Python
1947 to crash if the element comparison routines for the dict keys and/or
1948 values mutated the dicts. Making the code bulletproof slowed it down.
1949
Tim Peterseb28ef22001-06-02 05:27:19 +00001950- Collisions in dicts are resolved via a new approach, which can help
1951 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001952 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001953 faster now. Thanks to Christian Tismer for pointing out the cause and
1954 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001955
Tim Peters52e155e2001-06-16 05:42:57 +00001956- repr() is much faster for large containers (dict, list, tuple).
1957
1958
Tim Petersa814db52001-05-14 07:05:58 +00001959Library
1960
Fred Drake960fdf92001-07-20 18:38:26 +00001961- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00001962 were added to the string module. These a locale-independent
Fred Drake960fdf92001-07-20 18:38:26 +00001963 constants, unlike letters, lowercase, and uppercase. These are now
1964 use in appropriate locations in the standard library.
1965
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001966- The flags used in dlopen calls can now be configured using
1967 sys.setdlopenflags and queried using sys.getdlopenflags.
1968
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001969- Fredrik Lundh's xmlrpclib is now a standard library module. This
1970 provides full client-side XML-RPC support. In addition,
1971 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1972 one asyncore-based). Thanks to Eric Raymond for the documentation.
1973
Guido van Rossum643d3912001-07-05 14:46:25 +00001974- The xrange() object is simplified: it no longer supports slicing,
1975 repetition, comparisons, efficient 'in' checking, the tolist()
1976 method, or the start, stop and step attributes. See PEP 260.
1977
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001978- A new function fnmatch.filter to filter lists of file names was added.
1979
Barry Warsawffd674d2001-05-22 16:00:10 +00001980- calendar.py uses month and day names based on the current locale.
1981
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001982- strop is now *really* obsolete (this was announced before with 1.6),
1983 and issues DeprecationWarning when used (except for the four items
1984 that are still imported into string.py).
1985
Tim Petersa814db52001-05-14 07:05:58 +00001986- Cookie.py now sorts key+value pairs by key in output strings.
1987
1988- pprint.isrecursive(object) didn't correctly identify recursive objects.
1989 Now it does.
1990
Tim Peters95b3f782001-05-14 18:39:41 +00001991- pprint functions now much faster for large containers (tuple, list, dict).
1992
Tim Peters7b9542a2001-06-10 23:40:19 +00001993- New 'q' and 'Q' format codes in the struct module, corresponding to C
1994 types "long long" and "unsigned long long" (on Windows, __int64). In
1995 native mode, these can be used only when the platform C compiler supports
1996 these types (when HAVE_LONG_LONG is #define'd by the Python config
1997 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001998 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1999 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00002000
Guido van Rossum83213cc2001-06-12 16:48:52 +00002001- The site module installs a new built-in function 'help' that invokes
2002 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
2003 it displays a message reminding the user to use 'help()' or
2004 'help(object)'.
2005
Tim Petersa814db52001-05-14 07:05:58 +00002006Tests
2007
2008- New test_mutants.py runs dict comparisons where the key and value
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002009 comparison operators mutate the dicts randomly during comparison. This
Tim Petersa814db52001-05-14 07:05:58 +00002010 rapidly causes Python to crash under earlier releases (not for the faint
2011 of heart: it can also cause Win9x to freeze or reboot!).
2012
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002013- New test_pprint.py verifies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00002014 pprint.isreadable() return sensible results. Also verifies that simple
2015 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00002016
Tim Peters4324aa32001-05-28 22:30:08 +00002017C API
2018
2019- Removed the unused last_is_sticky argument from the internal
2020 _PyTuple_Resize(). If this affects you, you were cheating.
2021
2022
Guido van Rossum55a78992001-07-17 17:22:32 +00002023======================================================================
2024
2025
Guido van Rossumffe13be2001-04-16 18:46:45 +00002026What's New in Python 2.1 (final)?
2027=================================
2028
2029We only changed a few things since the last release candidate, all in
2030Python library code:
2031
2032- A bug in the locale module was fixed that affected locales which
2033 define no grouping for numeric formatting.
2034
2035- A few bugs in the weakref module's implementations of weak
2036 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
2037 and the test suite was updated to check for these bugs.
2038
2039- An old bug in the os.path.walk() function (introduced in Python
2040 2.0!) was fixed: a non-existent file would cause an exception
2041 instead of being ignored.
2042
2043- Fixed a few bugs in the new symtable module found by Neil Norwitz's
2044 PyChecker.
2045
2046
Guido van Rossum5b08f132001-04-16 02:05:23 +00002047What's New in Python 2.1c2?
2048===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00002049
Guido van Rossum5b08f132001-04-16 02:05:23 +00002050A flurry of small changes, and one showstopper fixed in the nick of
2051time made it necessary to release another release candidate. The list
2052here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00002053
Guido van Rossum5b08f132001-04-16 02:05:23 +00002054Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00002055
Guido van Rossum5b08f132001-04-16 02:05:23 +00002056- Tim discovered a nasty bug in the dictionary code, caused by
2057 PyDict_Next() calling dict_resize(), and the GC code's use of
2058 PyDict_Next() violating an assumption in dict_items(). This was
2059 fixed with considerable amounts of band-aid, but the net effect is a
2060 saner and more robust implementation.
2061
2062- Made a bunch of symbols static that were accidentally global.
2063
2064Build and Ports
2065
2066- The setup.py script didn't check for a new enough version of zlib
2067 (1.1.3 is needed). Now it does.
2068
2069- Changed "make clean" target to also remove shared libraries.
2070
2071- Added a more general warning about the SGI Irix optimizer to README.
2072
2073Library
2074
2075- Fix a bug in urllib.basejoin("http://host", "../file.html") which
2076 omitted the slash between host and file.html.
2077
2078- The mailbox module's _Mailbox class contained a completely broken
2079 and undocumented seek() method. Ripped it out.
2080
2081- Fixed a bunch of typos in various library modules (urllib2, smtpd,
2082 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
2083
2084- Fixed a few last-minute bugs in unittest.
2085
2086Extensions
2087
2088- Reverted the patch to the OpenSSL code in socketmodule.c to support
2089 RAND_status() and the EGD, and the subsequent patch that tried to
2090 fix it for pre-0.9.5 versions; the problem with the patch is that on
2091 some systems it issues a warning whenever socket is imported, and
2092 that's unacceptable.
2093
2094Tests
2095
2096- Fixed the pickle tests to work with "import test.test_pickle".
2097
2098- Tweaked test_locale.py to actually run the test Windows.
2099
2100- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
2101 not "wb" (which is not a valid mode at all).
2102
2103- Fix pstats browser crashes. Import readline if it exists to make
2104 the user interface nicer.
2105
2106- Add "import thread" to the top of test modules that import the
2107 threading module (test_asynchat and test_threadedtempfile). This
2108 prevents test failures caused by a broken threading module resulting
2109 from a previously caught failed import.
2110
2111- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
2112 needed on some platforms (e.g. Solaris 8) when the tests are run
2113 twice in succession.
2114
2115- Skip rather than fail test_sunaudiodev if no audio device is found.
2116
2117
2118What's New in Python 2.1c1?
2119===========================
2120
2121This list was significantly updated when 2.1c2 was released; the 2.1c1
2122release didn't mention most changes that were actually part of 2.1c1:
2123
2124Legal
2125
2126- Copyright was assigned to the Python Software Foundation (PSF) and a
2127 PSF license (very similar to the CNRI license) was added.
2128
2129- The CNRI copyright notice was updated to include 2001.
2130
2131Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00002132
Guido van Rossumc9932722001-04-12 02:31:27 +00002133- After a public outcry, assignment to __debug__ is no longer illegal;
2134 instead, a warning is issued. It will become illegal in 2.2.
2135
Guido van Rossum5b08f132001-04-16 02:05:23 +00002136- Fixed a core dump with "%#x" % 0, and changed the semantics so that
2137 "%#x" now always prepends "0x", even if the value is zero.
2138
2139- Fixed some nits in the bytecode compiler.
2140
2141- Fixed core dumps when calling certain kinds of non-functions.
2142
2143- Fixed various core dumps caused by reference count bugs.
2144
2145Build and Ports
2146
2147- Use INSTALL_SCRIPT to install script files.
2148
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002149- New port: SCO Unixware 7, by Billy G. Allie.
2150
Guido van Rossum5b08f132001-04-16 02:05:23 +00002151- Updated RISCOS port.
2152
2153- Updated BeOS port and notes.
2154
2155- Various other porting problems resolved.
2156
2157Library
2158
2159- The TERMIOS and SOCKET modules are now truly obsolete and
2160 unnecessary. Their symbols are incorporated in the termios and
2161 socket modules.
2162
2163- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
2164 better tests for pickling.
2165
2166- threading: make Condition.wait() robust against KeyboardInterrupt.
2167
2168- zipfile: add support to zipfile to support opening an archive
2169 represented by an open file rather than a file name. Fix bug where
2170 the archive was not properly closed. Fixed a bug in this bugfix
2171 where flush() was called for a read-only file.
2172
2173- imputil: added an uninstall() method to the ImportManager.
2174
2175- Canvas: fixed bugs in lower() and tkraise() methods.
2176
2177- SocketServer: API change (added overridable close_request() method)
2178 so that the TCP server can explicitly close the request.
2179
2180- pstats: Eric Raymond added a simple interactive statistics browser,
2181 invoked when the module is run as a script.
2182
2183- locale: fixed a problem in format().
2184
2185- webbrowser: made it work when the BROWSER environment variable has a
2186 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
2187 KDE 2. Fixed some other nits.
2188
2189- unittest: changes to allow using a different exception than
2190 AssertionError, and added a few more function aliases. Some other
2191 small changes.
2192
2193- urllib, urllib2: fixed redirect problems and a coupleof other nits.
2194
2195- asynchat: fixed a critical bug in asynchat that slipped through the
2196 2.1b2 release. Fixed another rare bug.
2197
2198- Fix some unqualified except: clauses (always a bad code example).
2199
2200XML
2201
2202- pyexpat: new API get_version_string().
2203
2204- Fixed some minidom bugs.
2205
2206Extensions
2207
2208- Fixed a core dump in _weakref. Removed the weakref.mapping()
2209 function (it adds nothing to the API).
2210
2211- Rationalized the use of header files in the readline module, to make
2212 it compile (albeit with some warnings) with the very recent readline
2213 4.2, without breaking for earlier versions.
2214
2215- Hopefully fixed a buffering problem in linuxaudiodev.
2216
2217- Attempted a fix to make the OpenSSL support in the socket module
2218 work again with pre-0.9.5 versions of OpenSSL.
2219
2220Tests
2221
2222- Added a test case for asynchat and asyncore.
2223
2224- Removed coupling between tests where one test failing could break
2225 another.
2226
2227Tools
2228
2229- Ping added an interactive help browser to pydoc, fixed some nits
2230 in the rest of the pydoc code, and added some features to his
2231 inspect module.
2232
2233- An updated python-mode.el version 4.1 which integrates Ken
2234 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
2235 much nicer in XEmacs and Emacs. When stepping through your program
2236 with pdb, in either the shell window or the *Python* window, the
2237 source file and line will be tracked by an arrow. Very cool!
2238
2239- IDLE: syntax warnings in interactive mode are changed into errors.
2240
2241- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00002242 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00002243
2244- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002245
Barry Warsaw11e89c72001-04-11 20:37:57 +00002246
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002247What's New in Python 2.1 beta 2?
2248================================
2249
Guido van Rossum053ae352001-03-22 14:17:21 +00002250(Unlisted are many fixed bugs, more documentation, etc.)
2251
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002252Core language, builtins, and interpreter
2253
Guido van Rossum053ae352001-03-22 14:17:21 +00002254- The nested scopes work (enabled by "from __future__ import
2255 nested_scopes") is completed; in particular, the future now extends
2256 into code executed through exec, eval() and execfile(), and into the
2257 interactive interpreter.
2258
2259- When calling a base class method (e.g. BaseClass.__init__(self)),
2260 this is now allowed even if self is not strictly spoken a class
2261 instance (e.g. when using metaclasses or the Don Beaudry hook).
2262
2263- Slice objects are now comparable but not hashable; this prevents
2264 dict[:] from being accepted but meaningless.
2265
2266- Complex division is now calculated using less braindead algorithms.
2267 This doesn't change semantics except it's more likely to give useful
2268 results in extreme cases. Complex repr() now uses full precision
2269 like float repr().
2270
2271- sgmllib.py now calls handle_decl() for simple <!...> declarations.
2272
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002273- It is illegal to assign to the name __debug__, which is set when the
2274 interpreter starts. It is effectively a compile-time constant.
2275
2276- A warning will be issued if a global statement for a variable
2277 follows a use or assignment of that variable.
2278
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002279Standard library
2280
Guido van Rossum053ae352001-03-22 14:17:21 +00002281- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
2282 inspired by JUnit), is now part of the standard library. You now
2283 have a choice of two testing frameworks: unittest requires you to
2284 write testcases as separate code, doctest gathers them from
2285 docstrings. Both approaches have their advantages and
2286 disadvantages.
2287
2288- A new module Tix was added, which wraps the Tix extension library
2289 for Tk. With that module, it is not necessary to statically link
2290 Tix with _tkinter, since Tix will be loaded with Tcl's "package
2291 require" command. See Demo/tix/.
2292
2293- tzparse.py is now obsolete.
2294
2295- In gzip.py, the seek() and tell() methods are removed -- they were
2296 non-functional anyway, and it's better if callers can test for their
2297 existence with hasattr().
2298
2299Python/C API
2300
2301- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
2302 that's already in the dictionary during a PyDict_Next() iteration.
2303 This used to fail occasionally when a dictionary resize operation
2304 could be triggered that would rehash all the keys. All other
2305 modifications to the dictionary are still off-limits during a
2306 PyDict_Next() iteration!
2307
2308- New extended APIs related to passing compiler variables around.
2309
2310- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
2311 implement isinstance() and issubclass().
2312
2313- Py_BuildValue() now has a "D" conversion to create a Python complex
2314 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002315
Fred Drake4e262a92001-03-22 18:26:47 +00002316- Extensions types which support weak references must now set the
2317 field allocated for the weak reference machinery to NULL themselves;
2318 this is done to avoid the cost of checking each object for having a
2319 weakly referencable type in PyObject_INIT(), since most types are
2320 not weakly referencable.
2321
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002322- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
2323 free variables and cell variables to and from the frame's f_locals.
2324
2325- Variants of several functions defined in pythonrun.h have been added
2326 to support the nested_scopes future statement. The variants all end
2327 in Flags and take an extra argument, a PyCompilerFlags *; examples:
2328 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
2329 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00002330 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002331
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002332Distutils
2333
2334- the sdist command now writes a PKG-INFO file, as described in PEP 241,
2335 into the release tree.
2336
Tim Peters0e57abf2001-05-02 07:39:38 +00002337- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002338 (an uninstaller, more customization of the installer's display)
2339
2340- from Jack Jansen: added Mac-specific code to generate a dialog for
2341 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00002342 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002343 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00002344
2345- added 'platforms' and 'keywords' to the set of metadata that can be
2346 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002347
2348- applied patches from Jason Tishler to make the compiler class work with
2349 Cygwin.
2350
2351
Tim Peters2fe289a2001-03-01 22:19:38 +00002352What's New in Python 2.1 beta 1?
2353================================
Tim Petersd66595f2001-02-04 03:09:53 +00002354
2355Core language, builtins, and interpreter
2356
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00002357- Following an outcry from the community about the amount of code
2358 broken by the nested scopes feature introduced in 2.1a2, we decided
2359 to make this feature optional, and to wait until Python 2.2 (or at
2360 least 6 months) to make it standard. The option can be enabled on a
2361 per-module basis by adding "from __future__ import nested_scopes" at
2362 the beginning of a module (before any other statements, but after
2363 comments and an optional docstring). See PEP 236 (Back to the
2364 __future__) for a description of the __future__ statement. PEP 227
2365 (Statically Nested Scopes) has been updated to reflect this change,
2366 and to clarify the semantics in a number of endcases.
2367
2368- The nested scopes code, when enabled, has been hardened, and most
2369 bugs and memory leaks in it have been fixed.
2370
2371- Compile-time warnings are now generated for a number of conditions
2372 that will break or change in meaning when nested scopes are enabled:
2373
2374 - Using "from...import *" or "exec" without in-clause in a function
2375 scope that also defines a lambda or nested function with one or
2376 more free (non-local) variables. The presence of the import* or
2377 bare exec makes it impossible for the compiler to determine the
2378 exact set of local variables in the outer scope, which makes it
2379 impossible to determine the bindings for free variables in the
2380 inner scope. To avoid the warning about import *, change it into
2381 an import of explicitly name object, or move the import* statement
2382 to the global scope; to avoid the warning about bare exec, use
2383 exec...in... (a good idea anyway -- there's a possibility that
2384 bare exec will be deprecated in the future).
2385
2386 - Use of a global variable in a nested scope with the same name as a
2387 local variable in a surrounding scope. This will change in
2388 meaning with nested scopes: the name in the inner scope will
2389 reference the variable in the outer scope rather than the global
2390 of the same name. To avoid the warning, either rename the outer
2391 variable, or use a global statement in the inner function.
2392
Neil Schemenauera35c6882001-02-27 04:45:05 +00002393- An optional object allocator has been included. This allocator is
2394 optimized for Python objects and should be faster and use less memory
2395 than the standard system allocator. It is not enabled by default
2396 because of possible thread safety problems. The allocator is only
2397 protected by the Python interpreter lock and it is possible that some
2398 extension modules require a thread safe allocator. The object
2399 allocator can be enabled by providing the "--with-pymalloc" option to
2400 configure.
2401
Tim Petersd66595f2001-02-04 03:09:53 +00002402Standard library
2403
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002404- pyexpat now detects the expat version if expat.h defines it. A
2405 number of additional handlers are provided, which are only available
2406 since expat 1.95. In addition, the methods SetParamEntityParsing and
2407 GetInputContext of Parser objects are available with 1.95.x
2408 only. Parser objects now provide the ordered_attributes and
2409 specified_attributes attributes. A new module expat.model was added,
2410 which offers a number of additional constants if 1.95.x is used.
2411
2412- xml.dom offers the new functions registerDOMImplementation and
2413 getDOMImplementation.
2414
2415- xml.dom.minidom offers a toprettyxml method. A number of DOM
2416 conformance issues have been resolved. In particular, Element now
2417 has an hasAttributes method, and the handling of namespaces was
2418 improved.
2419
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002420- Ka-Ping Yee contributed two new modules: inspect.py, a module for
2421 getting information about live Python code, and pydoc.py, a module
2422 for interactively converting docstrings to HTML or text.
2423 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002424 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002425 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2426 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002427
Tim Peters1eff7962001-03-01 02:31:33 +00002428- New library module difflib.py, primarily packaging the SequenceMatcher
2429 class at the heart of the popular ndiff.py file-comparison tool.
2430
2431- doctest.py (a framework for verifying Python code examples in docstrings)
2432 is now part of the std library.
2433
Tim Petersd66595f2001-02-04 03:09:53 +00002434Windows changes
2435
Guido van Rossume3955a82001-03-02 14:05:59 +00002436- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2437 small GUI that lets you browse the module docstrings using your
2438 default web browser.
2439
Tim Peters1eff7962001-03-01 02:31:33 +00002440- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2441 Platforms) is implemented. See
2442
2443 http://python.sourceforge.net/peps/pep-0235.html
2444
2445 for full details, especially the "Current Lower-Left Semantics" section.
2446 The new Windows import rules are simpler than before:
2447
2448 A. If the PYTHONCASEOK environment variable exists, same as
2449 before: silently accept the first case-insensitive match of any
2450 kind; raise ImportError if none found.
2451
2452 B. Else search sys.path for the first case-sensitive match; raise
2453 ImportError if none found.
2454
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002455 The same rules have been implemented on other platforms with case-
Tim Peters1eff7962001-03-01 02:31:33 +00002456 insensitive but case-preserving filesystems too (including Cygwin, and
2457 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002458
Tim Peters25a9ce32001-02-19 07:06:36 +00002459- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2460 what it's supposed to do (and does do under NT and 2000) via direct
2461 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002462 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002463 all Win9x systems before.
2464
Tim Peters1eff7962001-03-01 02:31:33 +00002465- Build: Subproject _test (effectively) renamed to _testcapi.
2466
Tim Peters2fe289a2001-03-01 22:19:38 +00002467New platforms
2468
2469- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2470 Thanks to Steven Majewski!
2471
2472- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2473 Tishler!
2474
Guido van Rossum9089b272001-03-02 06:49:50 +00002475- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2476 Schwertberger! See RISCOS/README for more information -- it seems
2477 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002478 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002479
Tim Peters25a9ce32001-02-19 07:06:36 +00002480
Tim Petersd7b5e882001-01-25 03:36:26 +00002481What's New in Python 2.1 alpha 2?
2482=================================
Tim Peters40ead762001-01-27 05:35:26 +00002483
Tim Petersd7b5e882001-01-25 03:36:26 +00002484Core language, builtins, and interpreter
2485
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002486- Scopes nest. If a name is used in a function or class, but is not
2487 local, the definition in the nearest enclosing function scope will
2488 be used. One consequence of this change is that lambda statements
2489 could reference variables in the namespaces where the lambda is
2490 defined. In some unusual cases, this change will break code.
2491
2492 In all previous version of Python, names were resolved in exactly
2493 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002494 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002495 function A is defined within a function B, the names bound in B are
2496 not visible in A. The new rules make names bound in B visible in A,
2497 unless A contains a name binding that hides the binding in B.
2498
2499 Section 4.1 of the reference manual describes the new scoping rules
2500 in detail. The test script in Lib/test/test_scope.py demonstrates
2501 some of the effects of the change.
2502
2503 The new rules will cause existing code to break if it defines nested
2504 functions where an outer function has local variables with the same
2505 name as globals or builtins used by the inner function. Example:
2506
2507 def munge(str):
2508 def helper(x):
2509 return str(x)
2510 if type(str) != type(''):
2511 str = helper(str)
2512 return str.strip()
2513
2514 Under the old rules, the name str in helper() is bound to the
2515 builtin function str(). Under the new rules, it will be bound to
2516 the argument named str and an error will occur when helper() is
2517 called.
2518
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002519- The compiler will report a SyntaxError if "from ... import *" occurs
2520 in a function or class scope. The language reference has documented
2521 that this case is illegal, but the compiler never checked for it.
2522 The recent introduction of nested scope makes the meaning of this
2523 form of name binding ambiguous. In a future release, the compiler
2524 may allow this form when there is no possibility of ambiguity.
2525
Tim Peters40ead762001-01-27 05:35:26 +00002526- repr(string) is easier to read, now using hex escapes instead of octal,
2527 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2528
2529 >>> "\texample \r\n" + chr(0) + chr(255)
2530 '\texample \r\n\x00\xff' # in 2.1
2531 '\011example \015\012\000\377' # in 2.0
2532
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002533- Functions are now compared and hashed by identity, not by value, since
2534 the func_code attribute is writable.
2535
Fred Drakefb9d7122001-02-01 20:00:40 +00002536- Weak references (PEP 205) have been added. This involves a few
2537 changes in the core, an extension module (_weakref), and a Python
2538 module (weakref). The weakref module is the public interface. It
2539 includes support for "explicit" weak references, proxy objects, and
2540 mappings with weakly held values.
2541
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002542- A 'continue' statement can now appear in a try block within the body
2543 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002544 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002545
Tim Petersd7b5e882001-01-25 03:36:26 +00002546Standard library
2547
Barry Warsaw30dbd142001-01-31 22:14:01 +00002548- mailbox.py now has a new class, PortableUnixMailbox which is
2549 identical to UnixMailbox but uses a more portable scheme for
2550 determining From_ separators. Also, the constructors for all the
2551 classes in this module have a new optional `factory' argument, which
2552 is a callable used when new message classes must be instantiated by
2553 the next() method.
2554
Tim Petersd7b5e882001-01-25 03:36:26 +00002555- random.py is now self-contained, and offers all the functionality of
2556 the now-deprecated whrandom.py. See the docs for details. random.py
2557 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002558 and restoring the internal state of the generator; and jumpahead(n),
2559 for quickly forcing the internal state to be the same as if n calls to
2560 random() had been made. The latter is particularly useful for multi-
2561 threaded programs, creating one instance of the random.Random() class for
2562 each thread, then using .jumpahead() to force each instance to use a
2563 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002564
Tim Peters0de88fc2001-02-01 04:59:18 +00002565- random.py's seed() function is new. For bit-for-bit compatibility with
2566 prior releases, use the whseed function instead. The new seed function
2567 addresses two problems: (1) The old function couldn't produce more than
2568 about 2**24 distinct internal states; the new one about 2**45 (the best
2569 that can be done in the Wichmann-Hill generator). (2) The old function
2570 sometimes produced identical internal states when passed distinct
2571 integers, and there was no simple way to predict when that would happen;
2572 the new one guarantees to produce distinct internal states for all
2573 arguments in [0, 27814431486576L).
2574
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002575- The socket module now supports raw packets on Linux. The socket
2576 family is AF_PACKET.
2577
Tim Peters9ea17ac2001-02-02 05:57:15 +00002578- test_capi.py is a start at running tests of the Python C API. The tests
2579 are implemented by the new Modules/_testmodule.c.
2580
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002581- A new extension module, _symtable, provides provisional access to the
2582 internal symbol table used by the Python compiler. A higher-level
2583 interface will be added on top of _symtable in a future release.
2584
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002585- Removed the obsolete soundex module.
2586
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002587- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2588 the isSameNode method; NamedNodeMap the get method.
2589
2590- xml.sax.expatreader supports the lexical handler property; it
2591 generates comment, startCDATA, and endCDATA events.
2592
Tim Petersee826f82001-01-31 19:39:44 +00002593Windows changes
2594
2595- Build procedure: the zlib project is built in a different way that
2596 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002597 the zlib binary used. See PCbuild\readme.txt for details. Your old
2598 zlib-related directories can be deleted; you'll need to download fresh
2599 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002600
Tim Peters9ea17ac2001-02-02 05:57:15 +00002601- Build: New subproject _test for the benefit of test_capi.py (see above).
2602
Tim Petersb16c56f2001-02-02 21:24:51 +00002603- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2604 interface to some Python compiler internals).
2605
2606- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002607 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002608
Tim Petersa3a3a032000-11-30 05:22:44 +00002609What's New in Python 2.1 alpha 1?
2610=================================
2611
2612Core language, builtins, and interpreter
2613
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002614- There is a new Unicode companion to the PyObject_Str() API
2615 called PyObject_Unicode(). It behaves in the same way as the
2616 former, but assures that the returned value is an Unicode object
2617 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002618
Guido van Rossumf98eda02001-01-17 15:54:45 +00002619- The comparison operators support "rich comparison overloading" (PEP
2620 207). C extension types can provide a rich comparison function in
2621 the new tp_richcompare slot in the type object. The cmp() function
2622 and the C function PyObject_Compare() first try the new rich
2623 comparison operators before trying the old 3-way comparison. There
2624 is also a new C API PyObject_RichCompare() (which also falls back on
2625 the old 3-way comparison, but does not constrain the outcome of the
2626 rich comparison to a Boolean result).
2627
2628 The rich comparison function takes two objects (at least one of
2629 which is guaranteed to have the type that provided the function) and
2630 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2631 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2632 object, which may be NotImplemented (in which case the tp_compare
2633 slot function is used as a fallback, if defined).
2634
2635 Classes can overload individual comparison operators by defining one
2636 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002637 __ge__. There are no explicit "reflected argument" versions of
2638 these; instead, __lt__ and __gt__ are each other's reflection,
2639 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2640 reflection (similar at the C level). No other implications are
2641 made; in particular, Python does not assume that == is the Boolean
2642 inverse of !=, or that < is the Boolean inverse of >=. This makes
2643 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002644
2645 Classes or types that want to implement (in)equality tests but not
2646 the ordering operators (i.e. unordered types) should implement ==
2647 and !=, and raise an error for the ordering operators.
2648
Guido van Rossuma88479f2001-01-18 14:28:08 +00002649 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002650 Boolean; e.g. a matrix type might want to return a matrix of bits
2651 for A < B, giving elementwise comparisons. Such types should ensure
2652 that any interpretation of their value in a Boolean context raises
2653 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2654 at the C level) to always raise an exception.
2655
Guido van Rossuma88479f2001-01-18 14:28:08 +00002656- Complex numbers use rich comparisons to define == and != but raise
2657 an exception for <, <=, > and >=. Unfortunately, this also means
2658 that cmp() of two complex numbers raises an exception when the two
2659 numbers differ. Since it is not mathematically meaningful to compare
2660 complex numbers except for equality, I hope that this doesn't break
2661 too much code.
2662
Tim Peters3389f192001-02-18 08:48:49 +00002663- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002664 not defined by the language, other than that it's arbitrary but
2665 consistent (see the Reference Manual). An implementation detail changed
2666 in 2.1a1 such that None now compares less than any other object. Code
2667 relying on this new behavior (like code that relied on the previous
2668 behavior) does so at its own risk.
2669
Barry Warsaw573b5412001-01-15 20:43:18 +00002670- Functions and methods now support getting and setting arbitrarily
2671 named attributes (PEP 232). Functions have a new __dict__
2672 (a.k.a. func_dict) which hold the function attributes. Methods get
2673 and set attributes on their underlying im_func. It is a TypeError
2674 to set an attribute on a bound method.
2675
Guido van Rossum051e3352001-01-15 19:11:10 +00002676- The xrange() object implementation has been improved so that
2677 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2678 limitation that in this case len(xrange(sys.maxint)) can't be
2679 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2680 work fine as long as the index i doesn't actually reach 2**31.
2681 (Python uses regular ints for sequence and string indices; fixing
2682 that is much more work.)
2683
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002684- Two changes to from...import:
2685
Guido van Rossumba381232001-02-03 15:06:40 +00002686 1) "from M import X" now works even if (after loading module M)
2687 sys.modules['M'] is not a real module; it's basically a getattr()
2688 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002689
2690 2) "from M import *" now looks for M.__all__ to decide which names to
2691 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2692 filters out names starting with '_' as before. Whether or not
2693 __all__ exists, there's no restriction on the type of M.
2694
Guido van Rossumf61f1662001-01-10 20:13:55 +00002695- File objects have a new method, xreadlines(). This is the fastest
2696 way to iterate over all lines in a file:
2697
2698 for line in file.xreadlines():
2699 ...do something to line...
2700
2701 See the xreadlines module (mentioned below) for how to do this for
2702 other file-like objects.
2703
2704- Even if you don't use file.xreadlines(), you may expect a speedup on
2705 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002706 quite a bit in platform-specific ways: on systems (like Linux) that
2707 support flockfile(), getc_unlocked(), and funlockfile(), those are
2708 used by default. On systems (like Windows) without getc_unlocked(),
2709 a complicated (but still thread-safe) method using fgets() is used by
2710 default.
2711
Tim Petersd52269b2001-01-25 06:23:18 +00002712 You can force use of the fgets() method by #define'ing
2713 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002714 getc_unlocked()).
2715
Tim Petersd52269b2001-01-25 06:23:18 +00002716 You can force fgets() not to be used by #define'ing
2717 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002718 test_bufio.py fails -- and let us know if it does!).
2719
2720- In addition, the fileinput module, while still slower than the other
2721 methods on most platforms, has been sped up too, by using
2722 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002723
2724- Support for run-time warnings has been added, including a new
2725 command line option (-W) to specify the disposition of warnings.
2726 See the description of the warnings module below.
2727
2728- Extensive changes have been made to the coercion code. This mostly
2729 affects extension modules (which can now implement mixed-type
2730 numerical operators without having to use coercion), but
2731 occasionally, in boundary cases the coercion semantics have changed
2732 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002733 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002734 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002735 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002736
Guido van Rossumf98eda02001-01-17 15:54:45 +00002737- In connection with the coercion changes, a new built-in singleton
2738 object, NotImplemented is defined. This can be returned for
2739 operations that wish to indicate they are not implemented for a
2740 particular combination of arguments. From C, this is
2741 Py_NotImplemented.
2742
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002743- The interpreter accepts now bytecode files on the command line even
2744 if they do not have a .pyc or .pyo extension. On Linux, after executing
2745
Martin v. Löwise214baa2001-02-04 22:37:56 +00002746import imp,sys,string
2747magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2748reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2749open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002750
2751 any byte code file can be used as an executable (i.e. as an argument
2752 to execve(2)).
2753
Tim Peters9940b802000-12-01 07:59:35 +00002754- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002755 character. In 1.6 and earlier, they never produced a sign,
2756 and raised an error if the value of the long was too large
2757 to fit in a Python int. In 2.0, they produced a sign if and
2758 only if too large to fit in an int. This was inconsistent
2759 across platforms (because the size of an int varies across
2760 platforms), and inconsistent with hex() and oct(). Example:
2761
2762 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002763 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002764 'ffffffbe' # in 2.0 and before, on 32-bit machines
2765 >>> hex(-0x42L)
2766 '-0x42L' # in all versions of Python
2767
Tim Peters9940b802000-12-01 07:59:35 +00002768 The behavior of %d formats for negative Python longs remains
2769 the same as in 2.0 (although in 1.6 and before, they raised
2770 an error if the long didn't fit in a Python int).
2771
2772 %u formats don't make sense for Python longs, but are allowed
2773 and treated the same as %d in 2.1. In 2.0, a negative long
2774 formatted via %u produced a sign if and only if too large to
2775 fit in an int. In 1.6 and earlier, a negative long formatted
2776 via %u raised an error if it was too big to fit in an int.
2777
Guido van Rossum3661d392000-12-12 22:10:31 +00002778- Dictionary objects have an odd new method, popitem(). This removes
2779 an arbitrary item from the dictionary and returns it (in the form of
2780 a (key, value) pair). This can be useful for algorithms that use a
2781 dictionary as a bag of "to do" items and repeatedly need to pick one
2782 item. Such algorithms normally end up running in quadratic time;
2783 using popitem() they can usually be made to run in linear time.
2784
Tim Peters36cdad12000-12-29 02:06:45 +00002785Standard library
2786
Thomas Woutersfe385252001-01-19 23:16:56 +00002787- In the time module, the time argument to the functions strftime,
2788 localtime, gmtime, asctime and ctime is now optional, defaulting to
2789 the current time (in the local timezone).
2790
Guido van Rossumda91f222001-01-15 16:36:08 +00002791- The ftplib module now defaults to passive mode, which is deemed a
2792 more useful default given that clients are often inside firewalls
2793 these days. Note that this could break if ftplib is used to connect
2794 to a *server* that is inside a firewall, from outside; this is
2795 expected to be a very rare situation. To fix that, you can call
2796 ftp.set_pasv(0).
2797
Martin v. Löwis10a27872001-01-13 09:54:41 +00002798- The module site now treats .pth files not only for path configuration,
2799 but also supports extensions to the initialization code: Lines starting
2800 with import are executed.
2801
Guido van Rossumf61f1662001-01-10 20:13:55 +00002802- There's a new module, warnings, which implements a mechanism for
2803 issuing and filtering warnings. There are some new built-in
2804 exceptions that serve as warning categories, and a new command line
2805 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2806 turns warnings into errors). warnings.warn(message[, category])
2807 issues a warning message; this can also be called from C as
2808 PyErr_Warn(category, message).
2809
2810- A new module xreadlines was added. This exports a single factory
2811 function, xreadlines(). The intention is that this code is the
2812 absolutely fastest way to iterate over all lines in an open
2813 file(-like) object:
2814
2815 import xreadlines
2816 for line in xreadlines.xreadlines(file):
2817 ...do something to line...
2818
2819 This is equivalent to the previous the speed record holder using
2820 file.readlines(sizehint). Note that if file is a real file object
2821 (as opposed to a file-like object), this is equivalent:
2822
2823 for line in file.xreadlines():
2824 ...do something to line...
2825
Tim Peters36cdad12000-12-29 02:06:45 +00002826- The bisect module has new functions bisect_left, insort_left,
2827 bisect_right and insort_right. The old names bisect and insort
2828 are now aliases for bisect_right and insort_right. XXX_right
2829 and XXX_left methods differ in what happens when the new element
2830 compares equal to one or more elements already in the list: the
2831 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002832 right. Code that doesn't care where equal elements end up should
2833 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002834
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002835- The new curses.panel module wraps the panel library that forms part
2836 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2837
Guido van Rossumf61f1662001-01-10 20:13:55 +00002838- The SocketServer module now sets the allow_reuse_address flag by
2839 default in the TCPServer class.
2840
2841- A new function, sys._getframe(), returns the stack frame pointer of
2842 the caller. This is intended only as a building block for
2843 higher-level mechanisms such as string interpolation.
2844
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002845- The pyexpat module supports a number of new handlers, which are
2846 available only in expat 1.2. If invocation of a callback fails, it
2847 will report an additional frame in the traceback. Parser objects
2848 participate now in garbage collection. If expat reports an unknown
2849 encoding, pyexpat will try to use a Python codec; that works only
2850 for single-byte charsets. The parser type objects is exposed as
2851 XMLParserObject.
2852
2853- xml.dom now offers standard definitions for symbolic node type and
2854 exception code constants, and a hierarchy of DOM exceptions. minidom
2855 was adjusted to use them.
2856
2857- The conformance of xml.dom.minidom to the DOM specification was
2858 improved. It detects a number of additional error cases; the
2859 previous/next relationship works even when the tree is modified;
2860 Node supports the normalize() method; NamedNodeMap, DocumentType and
2861 DOMImplementation classes were added; Element supports the
2862 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2863 method.
2864
Guido van Rossumf61f1662001-01-10 20:13:55 +00002865Build issues
2866
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002867- For Unix (and Unix-compatible) builds, configuration and building of
2868 extension modules is now greatly automated. Rather than having to
2869 edit the Modules/Setup file to indicate which modules should be
2870 built and where their include files and libraries are, a
2871 distutils-based setup.py script now takes care of building most
2872 extension modules. All extension modules built this way are built
2873 as shared libraries. Only a few modules that must be linked
2874 statically are still listed in the Setup file; you won't need to
2875 edit their configuration.
2876
2877- Python should now build out of the box on Cygwin. If it doesn't,
2878 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002879
2880- Python now always uses its own (renamed) implementation of getopt()
2881 -- there's too much variation among C library getopt()
2882 implementations.
2883
2884- C++ compilers are better supported; the CXX macro is always set to a
2885 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002886
Tim Petersd92dfe02000-12-12 01:18:41 +00002887Windows changes
2888
2889- select module: By default under Windows, a select() call
2890 can specify no more than 64 sockets. Python now boosts
2891 this Microsoft default to 512. If you need even more than
2892 that, see the MS docs (you'll need to #define FD_SETSIZE
2893 and recompile Python from source).
2894
Guido van Rossumf61f1662001-01-10 20:13:55 +00002895- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2896 subdirectory is no more!
2897
Tim Petersa3a3a032000-11-30 05:22:44 +00002898
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002899What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002900=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002901
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002902Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002903changes are in the file HISTORY. If you are making the jump directly
2904from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2905HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002906
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002907Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2908the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2909http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002910
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002911--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002912
2913======================================================================
2914
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002915What's new in 2.0 (since release candidate 1)?
2916==============================================
2917
2918Standard library
2919
2920- The copy_reg module was modified to clarify its intended use: to
2921 register pickle support for extension types, not for classes.
2922 pickle() will raise a TypeError if it is passed a class.
2923
2924- Fixed a bug in gettext's "normalize and expand" code that prevented
2925 it from finding an existing .mo file.
2926
2927- Restored support for HTTP/0.9 servers in httplib.
2928
Tim Peters989b7b92000-10-16 20:24:53 +00002929- The math module was changed to stop raising OverflowError in case of
2930 underflow, and return 0 instead in underflow cases. Whether Python
2931 used to raise OverflowError in case of underflow was platform-
2932 dependent (it did when the platform math library set errno to ERANGE
2933 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002934
2935- Fixed a bug in StringIO that occurred when the file position was not
2936 at the end of the file and write() was called with enough data to
2937 extend past the end of the file.
2938
2939- Fixed a bug that caused Tkinter error messages to get lost on
2940 Windows. The bug was fixed by replacing direct use of
2941 interp->result with Tcl_GetStringResult(interp).
2942
2943- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2944 redirect response.
2945
2946- Several changes were made to distutils: Some debugging code was
2947 removed from util. Fixed the installer used when an external zip
2948 program (like WinZip) is not found; the source code for this
2949 installer is in Misc/distutils. check_lib() was modified to behave
2950 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2951 test for whether installed modules are on sys.path was changed to
2952 use both normcase() and normpath().
2953
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002954- Several minor bugs were fixed in the xml package (the minidom,
2955 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002956
2957- The regression test driver (regrtest.py) behavior when invoked with
2958 -l changed: It now reports a count of objects that are recognized as
2959 garbage but not freed by the garbage collector.
2960
Tim Peters989b7b92000-10-16 20:24:53 +00002961- The regression test for the math module was changed to test
2962 exceptional behavior when the test is run in verbose mode. Python
2963 cannot yet guarantee consistent exception behavior across platforms,
2964 so the exception part of test_math is run only in verbose mode, and
2965 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002966
2967Internals
2968
2969- PyOS_CheckStack() has been disabled on Win64, where it caused
2970 test_sre to fail.
2971
2972Build issues
2973
2974- Changed compiler flags, so that gcc is always invoked with -Wall and
2975 -Wstrict-prototypes. Users compiling Python with GCC should see
2976 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002977 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002978 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002979
Tim Petersa3a3a032000-11-30 05:22:44 +00002980- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002981
2982Tools and other miscellany
2983
2984- The compiler in Tools/compiler was updated to support the new
2985 language features introduced in 2.0: extended print statement, list
2986 comprehensions, and augmented assignments. The new compiler should
2987 also be backwards compatible with Python 1.5.2; the compiler will
2988 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002989 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002990
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002991What's new in 2.0 release candidate 1 (since beta 2)?
2992=====================================================
2993
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002994What is release candidate 1?
2995
2996We believe that release candidate 1 will fix all known bugs that we
2997intend to fix for the 2.0 final release. This release should be a bit
2998more stable than the previous betas. We would like to see even more
2999widespread testing before the final release, so we are producing this
3000release candidate. The final release will be exactly the same unless
3001any show-stopping (or brown bag) bugs are found by testers of the
3002release candidate.
3003
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003004All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003005to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003006
3007Core language, builtins, and interpreter
3008
3009- A bug that caused crashes when __coerce__ was used with augmented
3010 assignment, e.g. +=, was fixed.
3011
3012- Raise ZeroDivisionError when raising zero to a negative number,
3013 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
3014 power operator and the result of math.pow(0.0, -2.0) will vary by
3015 platform. On Linux, it raises a ValueError.
3016
3017- A bug in Unicode string interpolation was fixed that occasionally
3018 caused errors with formats including "%%". For example, the
3019 following expression "%% %s" % u"abc" no longer raises a TypeError.
3020
3021- Compilation of deeply nested expressions raises MemoryError instead
3022 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
3023
3024- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
3025 rendering them useless. They are now written in binary mode again.
3026
3027Standard library
3028
3029- Keyword arguments are now accepted for most pattern and match object
3030 methods in SRE, the standard regular expression engine.
3031
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003032- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00003033 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003034
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003035- Several bugs in the Unicode handling and error handling in _tkinter
3036 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003037
3038- Fix memory management errors in Merge() and Tkapp_Call() routines.
3039
3040- Several changes were made to cStringIO to make it compatible with
3041 the file-like object interface and with StringIO. If operations are
3042 performed on a closed object, an exception is raised. The truncate
3043 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00003044 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003045
3046- There were many changes made to the linuxaudiodev module and its
3047 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00003048 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003049
3050 Note that this module is named poorly, because it should work
3051 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00003052 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003053
3054 The module now raises exceptions when errors occur instead of
3055 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
3056 audio) and defines a getptr() method that calls the
3057 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
3058
3059- The library_version attribute, introduced in an earlier beta, was
3060 removed because it can not be supported with early versions of the C
3061 readline library, which provides no way to determine the version at
3062 compile-time.
3063
3064- The binascii module is now enabled on Win64.
3065
Tim Peters46446d62000-10-09 21:19:31 +00003066- tokenize.py no longer suffers "recursion depth" errors when parsing
3067 programs with very long string literals.
3068
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003069Internals
3070
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003071- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003072 which is called when the interpreter starts up to determine where
3073 the standard library is installed. These vulnerabilities affect all
3074 previous versions of Python and can be exploited by setting very
3075 long values for PYTHONHOME or argv[0]. The risk is greatest for a
3076 setuid Python script, although use of the wrapper in
3077 Misc/setuid-prog.c will eliminate the vulnerability.
3078
3079- Fixed garbage collection bugs in instance creation that were
3080 triggered when errors occurred during initialization. The solution,
3081 applied in cPickle and in PyInstance_New(), is to call
3082 PyObject_GC_Init() after the initialization of the object's
3083 container attributes is complete.
3084
3085- pyexpat adds definitions of PyModule_AddStringConstant and
3086 PyModule_AddObject if the Python version is less than 2.0, which
3087 provides compatibility with PyXML on Python 1.5.2.
3088
3089- If the platform has a bogus definition for LONG_BIT (the number of
3090 bits in a long), an error will be reported at compile time.
3091
3092- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
3093 collection crashes and possibly other, unreported crashes.
3094
3095- Fixed a memory leak in _PyUnicode_Fini().
3096
3097Build issues
3098
3099- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003100 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00003101 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003102
3103- The mmap.PAGESIZE constant is now initialized using sysconf when
3104 possible, which eliminates a dependency on -lucb for Reliant UNIX.
3105
3106- The md5 file should now compile on all platforms.
3107
3108- The select module now compiles on platforms that do not define
3109 POLLRDNORM and related constants.
3110
3111- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00003112 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003113
Jeremy Hylton10921202000-10-09 18:34:12 +00003114- BeOS: A number of changes were made to the build and installation
3115 process. ar-fake now operates on a directory of object files.
3116 dl_export.h is gone, and its macros now appear on the mwcc command
3117 line during build on PPC BeOS.
3118
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003119- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00003120 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003121
3122- Cygwin: Support for shared libraries, Tkinter, and sockets.
3123
3124- SunOS 4.1.4_JL: Fix test for directory existence in configure.
3125
3126Tools and other miscellany
3127
3128- Removed debugging prints from main used with freeze.
3129
Tim Peters46446d62000-10-09 21:19:31 +00003130- IDLE auto-indent no longer crashes when it encounters Unicode
3131 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003132
3133What's new in 2.0 beta 2 (since beta 1)?
3134========================================
3135
3136Core language, builtins, and interpreter
3137
Tim Peters482c0212000-09-26 06:33:09 +00003138- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003139 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003140
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003141- Add -h and -V command line options to print the usage message and
3142 Python version number and exit immediately.
3143
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003144- eval() and exec accept Unicode objects as code parameters.
3145
3146- getattr() and setattr() now also accept Unicode objects for the
3147 attribute name, which are converted to strings using the default
3148 encoding before lookup.
3149
3150- Multiplication on string and Unicode now does proper bounds
3151 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
3152 string is too long."
3153
3154- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00003155 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003156
Jeremy Hylton1b618592000-09-26 05:32:36 +00003157
3158Standard library and extensions
3159
Guido van Rossum5b08f132001-04-16 02:05:23 +00003160- socket module: the OpenSSL code now adds support for RAND_status()
3161 and EGD (Entropy Gathering Device).
3162
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003163- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00003164 argument checking; it still takes no arguments.
3165
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003166- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003167
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003168- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003169
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003170- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003171
3172- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003173 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003174
3175- copy: Copy Unicode objects atomically.
3176
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003177- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003178
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003179- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003180
Fred Drake67233bc2000-09-26 16:40:27 +00003181- dbm: Add get() and setdefault() methods to dbm object. Add constant
3182 `library' to module that names the library used. Added doc strings
3183 and method names to error messages. Uses configure to determine
3184 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
3185 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003186
3187- distutils: Update to version 0.9.3.
3188
3189- dl: Add several dl.RTLD_ constants.
3190
3191- fpectl: Now supported on FreeBSD.
3192
3193- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
3194 found by the collector will be saved in gc.garbage. This is useful
3195 for debugging a program that creates reference cycles.
3196
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003197- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00003198 of HTTP class. Do not close socket on zero-length response. Do not
3199 crash when server sends invalid content-length header.
3200
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003201- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003202
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003203- marshal: When reading a short, sign-extend on platforms where shorts
3204 are bigger than 16 bits. When reading a long, repair the unportable
3205 sign extension that was being done for 64-bit machines. (It assumed
3206 that signed right shift sign-extends.)
3207
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003208- operator: Add contains(), invert(), __invert__() as aliases for
3209 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003210
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003211- os: Add support for popen2() and popen3() on all platforms where
3212 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003213
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003214- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00003215 clicking on a file in Explorer (or passing the file name to the
3216 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003217
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003218- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00003219 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003220
3221- pickle: Now raises ValueError when an invalid pickle that contains
3222 a non-string repr where a string repr was expected. This behavior
3223 matches cPickle.
3224
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003225- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003226
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003227- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003228
3229- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003230 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003231 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003232
3233- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003234 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003235
3236- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00003237 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00003238 few cycles during startup since the first call to
3239 setdefaultencoding() will initialize the codec registry and the
3240 encodings package.
3241
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003242- socket: Support for size hint in readlines() method of object returned
3243 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003244
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003245- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00003246 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00003247 is followed by whitespace.
3248
Tim Petersa3a3a032000-11-30 05:22:44 +00003249- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003250
3251- struct: Check ranges for bytes and shorts.
3252
3253- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003254 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003255
3256- Tkinter: Image objects are now guaranteed to have unique ids. Set
3257 event.delta to zero if Tk version doesn't support mousewheel.
3258 Removed some debugging prints.
3259
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003260- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003261
Fred Drake67233bc2000-09-26 16:40:27 +00003262- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003263 which works around a bug in Norton AntiVirus 2000 that leads directly
3264 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003265
3266- xml: New version detection code allows PyXML to override standard
3267 XML package if PyXML version is greater than 0.6.1.
3268
Fred Drake64bb3802000-09-26 16:21:35 +00003269- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
3270 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
3271 tree only for nodes which are sufficiently interesting to a specific
3272 application. Does not provide the HTML-specific extensions. Still
3273 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003274
Fred Drake64bb3802000-09-26 16:21:35 +00003275- xml.sax: SAX 2 support for Python, including all the handler
3276 interfaces needed to process XML 1.0 compliant XML. Some
3277 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003278
Fred Drake64bb3802000-09-26 16:21:35 +00003279- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
3280 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003281
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003282
Jeremy Hylton1b618592000-09-26 05:32:36 +00003283C API
3284
3285- Add three new convenience functions for module initialization --
3286 PyModule_AddObject(), PyModule_AddIntConstant(), and
3287 PyModule_AddStringConstant().
3288
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003289- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00003290 removed and add #error to Python.h if NULL isn't defined after
3291 #include of stdio.h.
3292
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003293- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00003294 backwards compatibility (at the source level) with old extensions.
3295
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003296- A wrapper API was added for signal() and sigaction(). Instead of
3297 either function, always use PyOS_getsig() to get a signal handler
3298 and PyOS_setsig() to set one. A new convenience typedef
3299 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003300
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003301- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00003302 internal data buffer and size of a string object -- or the default
3303 encoded version of a Unicode object.
3304
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003305- PyString_Size() and PyString_AsString() accept Unicode objects.
3306
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003307- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00003308 exists). INT_MAX and LONG_MAX will always be defined, even if
3309 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003310
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003311- PyFloat_FromString takes a second argument, pend, that was
3312 effectively useless. It is now officially useless but preserved for
3313 backwards compatibility. If the pend argument is not NULL, *pend is
3314 set to NULL.
3315
3316- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
3317 for the attribute name. See note on getattr() above.
3318
3319- A few bug fixes to argument processing for Unicode.
3320 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
3321 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
3322 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00003323 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003324
3325- Py_BuildValue accepts B format (for bgen-generated code).
3326
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003327
Jeremy Hylton1b618592000-09-26 05:32:36 +00003328Internals
3329
3330- On Unix, fix code for finding Python installation directory so that
3331 it works when argv[0] is a relative path.
3332
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00003333- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003334 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00003335 rather than by generating a copy of the object.
3336
Tim Peters482c0212000-09-26 06:33:09 +00003337- Several of the internal Unicode tables are much smaller now, and
3338 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003339
Jeremy Hylton97693b02000-09-26 17:42:51 +00003340- In the garbage collector: Fixed bug in collection of tuples. Fixed
3341 bug that caused some instances to be removed from the container set
3342 while they were still live. Fixed parsing in gc.set_debug() for
3343 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003344
3345- Fixed refcount problem in instance deallocation that only occurred
3346 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
3347
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003348- On Windows, getpythonregpath is now protected against null data in
3349 registry key.
3350
3351- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00003352 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003353
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003354
Jeremy Hylton1b618592000-09-26 05:32:36 +00003355Build and platform-specific issues
3356
3357- Better support of GNU Pth via --with-pth configure option.
3358
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003359- Python/C API now properly exposed to dynamically-loaded extension
3360 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003361
3362- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
3363 Don't define MS_SYNC to be zero when it is undefined. Added missing
3364 prototypes in posixmodule.c.
3365
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003366- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003367 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003368
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003369- Fix largefile support on older NetBSD systems and OpenBSD by adding
3370 define for TELL64.
3371
3372
3373Tools and other miscellany
3374
3375- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
3376
3377- freeze: The modulefinder now works with 2.0 opcodes.
3378
Tim Petersa3a3a032000-11-30 05:22:44 +00003379- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003380 Move hackery of sys.argv until after the Tk instance has been
3381 created, which allows the application-specific Tkinter
3382 initialization to be executed if present; also pass an explicit
3383 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00003384
Jeremy Hylton1b618592000-09-26 05:32:36 +00003385
3386What's new in 2.0 beta 1?
3387=========================
3388
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003389Source Incompatibilities
3390------------------------
3391
3392None. Note that 1.6 introduced several incompatibilities with 1.5.2,
3393such as single-argument append(), connect() and bind(), and changes to
3394str(long) and repr(float).
3395
3396
3397Binary Incompatibilities
3398------------------------
3399
3400- Third party extensions built for Python 1.5.x or 1.6 cannot be used
3401with Python 2.0; these extensions will have to be rebuilt for Python
34022.0.
3403
3404- On Windows, attempting to import a third party extension built for
3405Python 1.5.x or 1.6 results in an immediate crash; there's not much we
3406can do about this. Check your PYTHONPATH environment variable!
3407
3408- Python bytecode files (*.pyc and *.pyo) are not compatible between
3409releases.
3410
3411
3412Overview of Changes Since 1.6
3413-----------------------------
3414
3415There are many new modules (including brand new XML support through
3416the xml package, and i18n support through the gettext module); a list
3417of all new modules is included below. Lots of bugs have been fixed.
3418
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003419The process for making major new changes to the language has changed
3420since Python 1.6. Enhancements must now be documented by a Python
3421Enhancement Proposal (PEP) before they can be accepted.
3422
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003423There are several important syntax enhancements, described in more
3424detail below:
3425
3426 - Augmented assignment, e.g. x += 1
3427
3428 - List comprehensions, e.g. [x**2 for x in range(10)]
3429
3430 - Extended import statement, e.g. import Module as Name
3431
3432 - Extended print statement, e.g. print >> file, "Hello"
3433
3434Other important changes:
3435
3436 - Optional collection of cyclical garbage
3437
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003438Python Enhancement Proposal (PEP)
3439---------------------------------
3440
3441PEP stands for Python Enhancement Proposal. A PEP is a design
3442document providing information to the Python community, or describing
3443a new feature for Python. The PEP should provide a concise technical
3444specification of the feature and a rationale for the feature.
3445
3446We intend PEPs to be the primary mechanisms for proposing new
3447features, for collecting community input on an issue, and for
3448documenting the design decisions that have gone into Python. The PEP
3449author is responsible for building consensus within the community and
3450documenting dissenting opinions.
3451
3452The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003453
3454Augmented Assignment
3455--------------------
3456
3457This must have been the most-requested feature of the past years!
3458Eleven new assignment operators were added:
3459
Guido van Rossume905e952000-09-05 12:42:46 +00003460 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003461
3462For example,
3463
3464 A += B
3465
3466is similar to
3467
3468 A = A + B
3469
3470except that A is evaluated only once (relevant when A is something
3471like dict[index].attr).
3472
3473However, if A is a mutable object, A may be modified in place. Thus,
3474if A is a number or a string, A += B has the same effect as A = A+B
3475(except A is only evaluated once); but if a is a list, A += B has the
3476same effect as A.extend(B)!
3477
3478Classes and built-in object types can override the new operators in
3479order to implement the in-place behavior; the not-in-place behavior is
3480used automatically as a fallback when an object doesn't implement the
3481in-place behavior. For classes, the method name is derived from the
3482method name for the corresponding not-in-place operator by inserting
3483an 'i' in front of the name, e.g. __iadd__ implements in-place
3484__add__.
3485
3486Augmented assignment was implemented by Thomas Wouters.
3487
3488
3489List Comprehensions
3490-------------------
3491
3492This is a flexible new notation for lists whose elements are computed
3493from another list (or lists). The simplest form is:
3494
3495 [<expression> for <variable> in <sequence>]
3496
Guido van Rossum56db0952000-09-06 23:34:25 +00003497For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003498This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003499
3500You can also add a condition:
3501
3502 [<expression> for <variable> in <sequence> if <condition>]
3503
3504For example, [w for w in words if w == w.lower()] would yield the list
3505of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003506than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003507
3508You can also have nested for loops and more than one 'if' clause. For
3509example, here's a function that flattens a sequence of sequences::
3510
3511 def flatten(seq):
3512 return [x for subseq in seq for x in subseq]
3513
3514 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3515
3516This prints
3517
3518 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3519
3520List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003521Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003522
3523
3524Extended Import Statement
3525-------------------------
3526
3527Many people have asked for a way to import a module under a different
3528name. This can be accomplished like this:
3529
3530 import foo
3531 bar = foo
3532 del foo
3533
3534but this common idiom gets old quickly. A simple extension of the
3535import statement now allows this to be written as follows:
3536
3537 import foo as bar
3538
3539There's also a variant for 'from ... import':
3540
3541 from foo import bar as spam
3542
3543This also works with packages; e.g. you can write this:
3544
3545 import test.regrtest as regrtest
3546
3547Note that 'as' is not a new keyword -- it is recognized only in this
3548context (this is only possible because the syntax for the import
3549statement doesn't involve expressions).
3550
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003551Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003552
3553
3554Extended Print Statement
3555------------------------
3556
3557Easily the most controversial new feature, this extension to the print
3558statement adds an option to make the output go to a different file
3559than the default sys.stdout.
3560
3561For example, to write an error message to sys.stderr, you can now
3562write:
3563
3564 print >> sys.stderr, "Error: bad dog!"
3565
3566As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003567evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003568
3569 print >> None, "Hello world"
3570
3571is equivalent to
3572
3573 print "Hello world"
3574
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003575Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003576
3577
3578Optional Collection of Cyclical Garbage
3579---------------------------------------
3580
3581Python is now equipped with a garbage collector that can hunt down
3582cyclical references between Python objects. It's no replacement for
3583reference counting; in fact, it depends on the reference counts being
3584correct, and decides that a set of objects belong to a cycle if all
3585their reference counts can be accounted for from their references to
3586each other. This devious scheme was first proposed by Eric Tiedemann,
3587and brought to implementation by Neil Schemenauer.
3588
3589There's a module "gc" that lets you control some parameters of the
3590garbage collection. There's also an option to the configure script
3591that lets you enable or disable the garbage collection. In 2.0b1,
3592it's on by default, so that we (hopefully) can collect decent user
3593experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003594performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003595off by default in the final 2.0 release.
3596
3597
3598Smaller Changes
3599---------------
3600
3601A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3602map(None, seq1, seq2, ...) when the sequences have the same length;
3603i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3604the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003605zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003606
3607sys.version_info is a tuple (major, minor, micro, level, serial).
3608
3609Dictionaries have an odd new method, setdefault(key, default).
3610dict.setdefault(key, default) returns dict[key] if it exists; if not,
3611it sets dict[key] to default and returns that value. Thus:
3612
3613 dict.setdefault(key, []).append(item)
3614
3615does the same work as this common idiom:
3616
3617 if not dict.has_key(key):
3618 dict[key] = []
3619 dict[key].append(item)
3620
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003621There are two new variants of SyntaxError that are raised for
3622indentation-related errors: IndentationError and TabError.
3623
3624Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3625escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003626
3627The limits on the size of expressions and file in Python source code
3628have been raised from 2**16 to 2**32. Previous versions of Python
3629were limited because the maximum argument size the Python VM accepted
3630was 2**16. This limited the size of object constructor expressions,
3631e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3632limit was raised thanks to a patch by Charles Waldman that effectively
3633fixes the problem. It is now much more likely that you will be
3634limited by available memory than by an arbitrary limit in Python.
3635
3636The interpreter's maximum recursion depth can be modified by Python
3637programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3638limit is the maximum number of recursive calls that can be made by
3639Python code. The limit exists to prevent infinite recursion from
3640overflowing the C stack and causing a core dump. The default value is
36411000. The maximum safe value for a particular platform can be found
3642by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003643
3644New Modules and Packages
3645------------------------
3646
3647atexit - for registering functions to be called when Python exits.
3648
3649imputil - Greg Stein's alternative API for writing custom import
3650hooks.
3651
3652pyexpat - an interface to the Expat XML parser, contributed by Paul
3653Prescod.
3654
3655xml - a new package with XML support code organized (so far) in three
3656subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3657would fill a volume. There's a special feature whereby a
3658user-installed package named _xmlplus overrides the standard
3659xmlpackage; this is intended to give the XML SIG a hook to distribute
3660backwards-compatible updates to the standard xml package.
3661
3662webbrowser - a platform-independent API to launch a web browser.
3663
3664
Guido van Rossume905e952000-09-05 12:42:46 +00003665Changed Modules
3666---------------
3667
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003668array -- new methods for array objects: count, extend, index, pop, and
3669remove
3670
3671binascii -- new functions b2a_hex and a2b_hex that convert between
3672binary data and its hex representation
3673
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003674calendar -- Many new functions that support features including control
3675over which day of the week is the first day, returning strings instead
3676of printing them. Also new symbolic constants for days of week,
3677e.g. MONDAY, ..., SUNDAY.
3678
3679cgi -- FieldStorage objects have a getvalue method that works like a
3680dictionary's get method and returns the value attribute of the object.
3681
3682ConfigParser -- The parser object has new methods has_option,
3683remove_section, remove_option, set, and write. They allow the module
3684to be used for writing config files as well as reading them.
3685
3686ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003687optionally support the RFC 959 REST command.
3688
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003689gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003690
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003691httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3692the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003693
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003694locale -- implement getdefaultlocale for Win32 and Macintosh
3695
3696marshal -- no longer dumps core when marshaling deeply nested or
3697recursive data structures
3698
3699os -- new functions isatty, seteuid, setegid, setreuid, setregid
3700
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003701os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3702support under Unix.
3703
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003704os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003705
3706os.path -- fix semantics of os.path.commonprefix
3707
3708smtplib -- support for sending very long messages
3709
3710socket -- new function getfqdn()
3711
3712readline -- new functions to read, write and truncate history files.
3713The readline section of the library reference manual contains an
3714example.
3715
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003716select -- add interface to poll system call
3717
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003718shutil -- new copyfileobj function
3719
3720SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3721HTTP server.
3722
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003723Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003724
3725urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003726e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003727
3728whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003729
3730
3731Obsolete Modules
3732----------------
3733
3734None. However note that 1.6 made a whole slew of modules obsolete:
3735stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3736poly, zmod, strop, util, whatsound.
3737
3738
3739Changed, New, Obsolete Tools
3740----------------------------
3741
Tim Peters8b092332000-09-05 20:15:25 +00003742None.
Guido van Rossume905e952000-09-05 12:42:46 +00003743
3744
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003745C-level Changes
3746---------------
3747
3748Several cleanup jobs were carried out throughout the source code.
3749
3750All C code was converted to ANSI C; we got rid of all uses of the
3751Py_PROTO() macro, which makes the header files a lot more readable.
3752
3753Most of the portability hacks were moved to a new header file,
3754pyport.h; several other new header files were added and some old
3755header files were removed, in an attempt to create a more rational set
3756of header files. (Few of these ever need to be included explicitly;
3757they are all included by Python.h.)
3758
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003759Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003760and Win64, especially for the new Intel Itanium processor. Mick also
3761added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003762
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003763The C APIs to return an object's size have been update to consistently
3764use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3765previous versions, the abstract interfaces used PyXXX_Length and the
3766concrete interfaces used PyXXX_Size. The old names,
3767e.g. PyObject_Length, are still available for backwards compatibility
3768at the API level, but are deprecated.
3769
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003770The PyOS_CheckStack function has been implemented on Windows by
3771Fredrik Lundh. It prevents Python from failing with a stack overflow
3772on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003773
3774The GC changes resulted in creation of two new slots on object,
3775tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003776the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003777
3778The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003779C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003780
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003781PyErr_Format has been updated to automatically calculate the size of
3782the buffer needed to hold the formatted result string. This change
3783prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003784
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003785New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003786
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003787PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3788that are the same as their non-Ex counterparts except they take an
3789extra flag argument that tells them to close the file when done.
3790
3791XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003792
Tim Peters8b092332000-09-05 20:15:25 +00003793
3794Windows Changes
3795---------------
3796
3797New popen2/popen3/peopen4 in os module (see Changed Modules above).
3798
3799os.popen is much more usable on Windows 95 and 98. See Microsoft
3800Knowledge Base article Q150956. The Win9x workaround described there
3801is implemented by the new w9xpopen.exe helper in the root of your
3802Python installation. Note that Python uses this internally; it is not
3803a standalone program.
3804
3805Administrator privileges are no longer required to install Python
3806on Windows NT or Windows 2000. If you have administrator privileges,
3807Python's registry info will be written under HKEY_LOCAL_MACHINE.
3808Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003809under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003810uses of Python, but will prevent some advanced uses from working
3811(for example, running a Python script as an NT service, or possibly
3812from CGI).
3813
3814[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3815installer; instead, it installs the needed Tcl/Tk files directly in the
3816Python directory. If you already have a Tcl/Tk installation, this
3817wastes some disk space (about 4 Megs) but avoids problems with
3818conflicting Tcl/Tk installations, and makes it much easier for Python
3819to ensure that Tcl/Tk can find all its files.
3820
3821[This was new in 1.6] The Windows installer now installs by default in
3822\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3823
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003824
3825Updates to the changes between 1.5.2 and 1.6
3826--------------------------------------------
3827
3828The 1.6 NEWS file can't be changed after the release is done, so here
3829is some late-breaking news:
3830
3831New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3832and changes to getlocale() and setlocale().
3833
3834The new module is now enabled per default.
3835
3836It is not true that the encodings codecs cannot be used for normal
3837strings: the string.encode() (which is also present on 8-bit strings
3838!) allows using them for 8-bit strings too, e.g. to convert files from
3839cp1252 (Windows) to latin-1 or vice-versa.
3840
3841Japanese codecs are available from Tamito KAJIYAMA:
3842http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3843
3844
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003845======================================================================