blob: 4e0c319d2d01b69871a292a0ab8b885b3b153278 [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
Martin v. Löwis94717ed2002-09-09 14:24:16 +0000277- The time stamps in os.stat_result are floating point numbers now if
278 the system supports that.
279
Neal Norwitzb5673922002-09-05 21:48:07 +0000280- If the size passed to mmap.mmap() is larger than the length of the
281 file on non-Windows platforms, a ValueError is raised. [SF bug 585792]
282
Guido van Rossumb57089c2002-08-06 16:20:26 +0000283- The xreadlines module is slated for obsolescence.
284
Guido van Rossum79f0a102002-07-23 03:32:08 +0000285- The strptime function in the time module is now always available (a
286 Python implementation is used when the C library doesn't define it).
287
Guido van Rossum9562bcf2002-06-14 21:31:18 +0000288- The 'new' module is no longer an extension, but a Python module that
289 only exists for backwards compatibility. Its contents are no longer
290 functions but callable type objects.
291
Tim Peters81b92512002-04-29 01:37:32 +0000292- The bsddb.*open functions can now take 'None' as a filename.
Anthony Baxter83888952002-04-23 02:11:05 +0000293 This will create a temporary in-memory bsddb that won't be
Tim Peters81b92512002-04-29 01:37:32 +0000294 written to disk.
Anthony Baxter83888952002-04-23 02:11:05 +0000295
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000296- posix.lchown, posix.killpg, posix.mknod, and posix.getpgid have been
297 added where available.
Martin v. Löwis06a83e92002-04-14 10:19:44 +0000298
Martin v. Löwis2e64c342002-03-27 18:49:02 +0000299- The locale module now exposes the C library's gettext interface.
300
Tim Petersfbf74f22002-03-14 19:06:01 +0000301- A security hole ("double free") was found in zlib-1.1.3, a popular
302 third party compression library used by some Python modules. The
303 hole was quickly plugged in zlib-1.1.4, and the Windows build of
304 Python now ships with zlib-1.1.4.
305
Martin v. Löwis688357e2002-04-08 21:28:20 +0000306- pwd, grp, and resource return enhanced tuples now, with symbolic
307 field names.
Martin v. Löwis29001ff2002-03-01 10:47:37 +0000308
Martin v. Löwis99866332002-03-01 10:27:01 +0000309- array.array is now a type object. A new format character
310 'u' indicates Py_UNICODE arrays. For those, .tounicode and
311 .fromunicode methods are available. Arrays now support __iadd__
312 and __imul__.
313
Neal Norwitze790eae2002-01-01 21:14:12 +0000314- dl now builds on every system that has dlfcn.h. Failure in case
Martin v. Löwis93227272002-01-01 20:18:30 +0000315 of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
316 is called.
317
Michael W. Hudson34f20ea2002-05-27 15:08:24 +0000318- signal.sigpending, signal.sigprocmask and signal.sigsuspend have
319 been added where available.
320
Skip Montanaro8e790e72002-09-03 13:25:17 +0000321- The sys module acquired a new attribute, api_version, which evaluates
322 to the value of the PYTHON_API_VERSION macro with which the
323 interpreter was compiled.
324
Tim Petersaf8446f2001-12-21 21:36:50 +0000325Library
326
Walter Dörwald5ccaf8f2002-09-06 16:15:58 +0000327- mimetypes has two new functions: guess_all_extensions() which
328 returns a list of all known extensions for a mime type, and
329 add_type() which adds one mapping between a mime type and
330 an extension to the database.
331
Guido van Rossumd8ab35c2002-08-19 16:25:46 +0000332- New module: sets, defines the class Set that implements a mutable
333 set type using the keys of a dict to represent the set. There's
334 also a class ImmutableSet which is useful when you need sets of sets
335 or when you need to use sets as dict keys, and a class BaseSet which
336 is the base class of the two. (This is not documented yet, but
337 help(sets) gives a wealth of information.)
338
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +0000339- Added operator.pow(a,b) which is equivalent to a**b.
340
Tim Peters012c0a32002-08-16 03:40:07 +0000341- random.randrange(-sys.maxint-1, sys.maxint) no longer raises
342 OverflowError. That is, it now accepts any combination of 'start'
343 and 'stop' arguments so long as each is in the range of Python's
344 bounded integers.
345
Guido van Rossum4a57c332002-08-02 18:05:20 +0000346- New "algorithms" module: heapq, implements a heap queue. Thanks to
347 Kevin O'Connor for the code and François Pinard for an entertaining
348 write-up explaining the theory and practical uses of heaps.
349
Marc-André Lemburg58e2ff22002-07-12 14:40:04 +0000350- New encoding for the Palm OS character set: palmos.
351
Tim Peters943382c2002-07-07 03:59:34 +0000352- binascii.crc32() and the zipfile module had problems on some 64-bit
353 platforms. These have been fixed. On a platform with 8-byte C longs,
354 crc32() now returns a signed-extended 4-byte result, so that its value
355 as a Python int is equal to the value computed a 32-bit platform.
356
Martin v. Löwis7d650ca2002-06-30 15:05:00 +0000357- xml.dom.minidom.toxml and toprettyxml now take an optional encoding
358 argument.
359
Guido van Rossum9f7549b2002-06-10 21:39:42 +0000360- Some fixes in the copy module: when an object is copied through its
361 __reduce__ method, there was no check for a __setstate__ method on
362 the result [SF patch 565085]; deepcopy should treat instances of
363 custom metaclasses the same way it treats instances of type 'type'
364 [SF patch 560794].
365
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000366- Sockets now support timeout mode. After s.settimeout(T), where T is
367 a float expressing seconds, subsequent operations raise an exception
368 if they cannot be completed within T seconds. To disable timeout
Guido van Rossum79f0a102002-07-23 03:32:08 +0000369 mode, use s.settimeout(None). There's also a module function,
370 socket.setdefaulttimeout(T), which sets the default for all sockets
371 created henceforth.
Guido van Rossum5033c8e2002-06-07 12:40:52 +0000372
373- getopt.gnu_getopt was added. This supports GNU-style option
374 processing, where options can be mixed with non-option arguments.
Martin v. Löwis446a25f2002-06-06 10:58:36 +0000375
Michael W. Hudsonb0dc1a32002-06-04 18:27:35 +0000376- Stop using strings for exceptions. String objects used for
377 exceptions are now classes deriving from Exception. The objects
378 changed were: Tkinter.TclError, bdb.BdbQuit, macpath.norm_error,
379 tabnanny.NannyNag, and xdrlib.Error.
Neal Norwitzb5b5a262002-06-04 17:14:07 +0000380
Walter Dörwald474458d2002-06-04 15:16:29 +0000381- Constants BOM_UTF8, BOM_UTF16, BOM_UTF16_LE, BOM_UTF16_BE,
382 BOM_UTF32, BOM_UTF32_LE and BOM_UTF32_BE that represent the Byte
383 Order Mark in UTF-8, UTF-16 and UTF-32 encodings for little and
384 big endian systems were added to the codecs module. The old names
385 BOM32_* and BOM64_* were off by a factor of 2.
386
Guido van Rossumf9257822002-06-18 20:43:18 +0000387- Added conversion functions math.degrees() and math.radians().
Raymond Hettinger87f59ee2002-05-13 04:17:32 +0000388
Raymond Hettinger9b1df1d2002-05-12 06:07:21 +0000389- ftplib.retrlines() now tests for callback is None rather than testing
390 for False. Was causing an error when given a callback object which
391 was callable but also returned len() as zero. The change may
392 create new breakage if the caller relied on the undocumented behavior
393 and called with callback set to [] or some other False value not
394 identical to None.
395
Tim Peters46c04e12002-05-05 20:40:00 +0000396- random.gauss() uses a piece of hidden state used by nothing else,
397 and the .seed() and .whseed() methods failed to reset it. In other
398 words, setting the seed didn't completely determine the sequence of
399 results produced by random.gauss(). It does now. Programs repeatedly
400 mixing calls to a seed method with calls to gauss() may see different
401 results now.
402
Fred Drake7f781c92002-05-01 20:33:53 +0000403- The pickle.Pickler class grew a clear_memo() method to mimic that
404 provided by cPickle.Pickler.
405
Tim Peters81b92512002-04-29 01:37:32 +0000406- difflib's SequenceMatcher class now does a dynamic analysis of
407 which elements are so frequent as to constitute noise. For
408 comparing files as sequences of lines, this generally works better
409 than the IS_LINE_JUNK function, and function ndiff's linejunk
410 argument defaults to None now as a result. A happy benefit is
411 that SequenceMatcher may run much faster now when applied
412 to large files with many duplicate lines (for example, C program
413 text with lots of repeated "}" and "return NULL;" lines).
414
Guido van Rossum256705b2002-04-23 13:29:43 +0000415- New Text.dump() method in Tkinter module.
416
Marc-André Lemburg1ec71ea2002-04-17 20:33:40 +0000417- New distutils commands for building packagers were added to
418 support pkgtool on Solaris and swinstall on HP-UX.
419
420- distutils now has a new abstract binary packager base class
421 command/bdist_packager, which simplifies writing packagers.
422 This will hopefully provide the missing bits to encourage
423 people to submit more packagers, e.g. for Debian, FreeBSD
424 and other systems.
425
Guido van Rossumf9257822002-06-18 20:43:18 +0000426- The UTF-16, -LE and -BE stream readers now raise a
427 NotImplementedError for all calls to .readline(). Previously, they
428 used to just produce garbage or fail with an encoding error --
429 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 +0000430 work well with these.
431
Martin v. Löwis5c137c22002-03-18 12:44:08 +0000432- compileall now supports quiet operation.
433
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000434- The BaseHTTPServer now implements optional HTTP/1.1 persistent
Martin v. Löwis587c98c2002-03-17 18:37:22 +0000435 connections.
436
Marc-André Lemburga5d2b4c2002-02-16 18:23:30 +0000437- socket module: the SSL support was broken out of the main
438 _socket module C helper and placed into a new _ssl helper
439 which now gets imported by socket.py if available and working.
440
Marc-André Lemburg37aa5802002-02-10 21:42:47 +0000441- encodings package: added aliases for all supported IANA character
442 sets
443
Guido van Rossum606fe4e2001-12-28 20:57:14 +0000444- ftplib: to safeguard the user's privacy, anonymous login will use
445 "anonymous@" as default password, rather than the real user and host
446 name.
447
Fred Drake36736122002-01-10 13:50:31 +0000448- webbrowser: tightened up the command passed to os.system() so that
449 arbitrary shell code can't be executed because a bogus URL was
450 passed in.
451
Tim Peters11bd9942002-02-01 00:52:29 +0000452- gettext.translation has an optional fallback argument, and
Martin v. Löwisa55ffae2002-01-11 06:58:49 +0000453 gettext.find an optional all argument. Translations will now fallback
454 on a per-message basis.
Martin v. Löwis1be64192002-01-11 06:33:28 +0000455
Martin v. Löwis9668b932002-01-12 11:27:42 +0000456- distutils bdist commands now offer a --skip-build option.
457
Walter Dörwaldb25c2b02002-03-21 10:38:40 +0000458- warnings.warn now accepts a Warning instance as first argument.
459
Fred Drakefed7e852002-04-04 19:36:15 +0000460- The xml.sax.expatreader.ExpatParser class will no longer create
461 circular references by using itself as the locator that gets passed
462 to the content handler implementation. [SF bug #535474]
463
Barry Warsaw47f3e2c2002-05-20 00:14:24 +0000464- The email.Parser.Parser class now properly parses strings regardless
465 of their line endings, which can be any of \r, \n, or \r\n (CR, LF,
466 or CRLF). Also, the Header class's constructor default arguments
467 has changed slightly so that an explicit maxlinelen value is always
468 honored.
469
Tim Petersaf8446f2001-12-21 21:36:50 +0000470Tools/Demos
471
Fred Drake40813b12002-08-05 15:24:19 +0000472- IDLE supports the new encoding declarations (PEP 263); it can also
473 deal with legacy 8-bit files if they use the locale's encoding. It
474 allows non-ASCII strings in the interactive shell and executes them
475 in the locale's encoding.
Martin v. Löwis98ce7b72002-08-05 15:11:26 +0000476
Marc-André Lemburg46260092002-04-04 16:17:11 +0000477- freeze.py now produces binaries which can import shared modules,
478 unlike before when this failed due to missing symbol exports in
479 the generated binary.
480
Tim Petersaf8446f2001-12-21 21:36:50 +0000481Build
482
Tim Petersf47630f2002-08-01 02:34:51 +0000483- The public Python C API will generally be declared using PyAPI_FUNC
Neal Norwitz1389f3e2002-07-22 13:21:10 +0000484 and PyAPI_DATA macros, while Python extension module init functions
485 will be declared with PyMODINIT_FUNC. DL_EXPORT/DL_IMPORT macros
486 are deprecated.
487
Tim Petersc6a3ff62002-07-08 22:11:52 +0000488- A bug was fixed that could cause COUNT_ALLOCS builds to segfault, or
489 get into infinite loops, when a new-style class got garbage-collected.
490 Unfortunately, to avoid this, the way COUNT_ALLOCS works requires
491 that new-style classes be immortal in COUNT_ALLOCS builds. Note that
492 COUNT_ALLOCS is not enabled by default, in either release or debug
493 builds, and that new-style classes are immortal only in COUNT_ALLOCS
494 builds.
495
Tim Peters943382c2002-07-07 03:59:34 +0000496- Compiling out the cyclic garbage collector is no longer an option.
497 The old symbol WITH_CYCLE_GC is now ignored, and Python.h arranges
498 that it's always defined (for the benefit of any extension modules
499 that may be conditionalizing on it). A bonus is that any extension
500 type participating in cyclic gc can choose to participate in the
501 Py_TRASHCAN mechanism now too; in the absence of cyclic gc, this used
502 to require editing the core to teach the trashcan mechanism about the
503 new type.
504
Martin v. Löwis0cec0ff2002-07-28 16:33:45 +0000505- According to Annex F of the current C standard,
Tim Peters1de41bf2002-07-03 03:31:20 +0000506
507 The Standard C macro HUGE_VAL and its float and long double analogs,
508 HUGE_VALF and HUGE_VALL, expand to expressions whose values are
509 positive infinities.
510
511 Python only uses the double HUGE_VAL, and only to #define its own symbol
512 Py_HUGE_VAL. Some platforms have incorrect definitions for HUGE_VAL.
513 pyport.h used to try to worm around that, but the workarounds triggered
514 other bugs on other platforms, so we gave up. If your platform defines
515 HUGE_VAL incorrectly, you'll need to #define Py_HUGE_VAL to something
516 that works on your platform. The only instance of this I'm sure about
517 is on an unknown subset of Cray systems, described here:
518
519 http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm
520
521 Presumably 2.3a1 breaks such systems. If anyone uses such a system, help!
522
Martin v. Löwisa3fb4f72002-06-09 13:33:54 +0000523- The configure option --without-doc-strings can be used to remove the
524 doc strings from the builtin functions and modules; this reduces the
525 size of the executable.
526
Guido van Rossumadd88062002-08-15 14:01:14 +0000527- The universal newlines option (PEP 278) is on by default. On Unix
528 it can be disabled by passing --without-universal-newlines to the
529 configure script. On other platforms, remove
530 WITH_UNIVERSAL_NEWLINES from pyconfig.h.
Tim Peters639295f2002-04-21 07:30:30 +0000531
Martin v. Löwis1142de32002-03-29 16:28:31 +0000532- On Unix, a shared libpython2.3.so can be created with --enable-shared.
533
Tim Peters8deda702002-03-30 10:06:07 +0000534- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
535 preprocessor symbols were eliminated. The internal decisions they
536 controlled stopped being experimental long ago.
Tim Peters1f7df352002-03-29 03:29:08 +0000537
Fred Drake7d28b732002-05-02 21:17:00 +0000538- The tools used to build the documentation now work under Cygwin as
539 well as Unix.
540
Skip Montanaro57454e52002-06-14 20:30:31 +0000541- The bsddb and dbm module builds have been changed to try and avoid version
542 skew problems and disable linkage with Berkeley DB 1.85 unless the
543 installer knows what s/he's doing. See the section on building these
544 modules in the README file for details.
545
Tim Petersaf8446f2001-12-21 21:36:50 +0000546C API
547
Guido van Rossum45ec02a2002-08-19 21:43:18 +0000548- The string object's layout has changed: the pointer member
549 ob_sinterned has been replaced by an int member ob_sstate. On some
550 platforms (e.g. most 64-bit systems) this may change the offset of
551 the ob_sval member, so as a precaution the API_VERSION has been
552 incremented. The apparently unused feature of "indirect interned
553 strings", supported by the ob_sinterned member, is gone. Interned
554 strings are now usually mortal; theres a new API,
555 PyString_InternImmortal() that creates immortal interned strings.
556 (The ob_sstate member can only take three values; however, while
557 making it a char saves a few bytes per string object on average, in
558 it also slowed things down a bit because ob_sval was no longer
559 aligned.)
560
Guido van Rossumfdb86482002-08-14 21:20:32 +0000561- The Py_InitModule*() functions now accept NULL for the 'methods'
562 argument. Modules without global functions are becoming more common
563 now that factories can be types rather than functions.
564
Marc-André Lemburgcc8764c2002-08-11 12:23:04 +0000565- New C API PyUnicode_FromOrdinal() which exposes unichr() at C
566 level.
567
Thomas Heller085358a2002-07-29 14:27:41 +0000568- New functions PyErr_SetExcFromWindowsErr() and
569 PyErr_SetExcFromWindowsErrWithFilename(). Similar to
570 PyErr_SetFromWindowsErrWithFilename() and
571 PyErr_SetFromWindowsErr(), but they allow to specify
572 the exception type to raise. Available on Windows.
573
Tim Peters7c321a82002-07-09 02:57:01 +0000574- Py_FatalError() is now declared as taking a const char* argument. It
575 was previously declared without const. This should not affect working
576 code.
577
Martin v. Löwis01f94bd2002-05-08 08:44:21 +0000578- Added new macro PySequence_ITEM(o, i) that directly calls
579 sq_item without rechecking that o is a sequence and without
580 adjusting for negative indices.
581
Fred Draked0ba6362002-05-02 21:28:26 +0000582- PyRange_New() now raises ValueError if the fourth argument is not 1.
583 This is part of the removal of deprecated features of the xrange
584 object.
585
Guido van Rossum517c7d42002-04-26 02:49:14 +0000586- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
587 coercion if both arguments have the same type but this type has the
588 CHECKTYPES flag set. This is to better support proxies.
589
Neil Schemenauer9344b142002-04-12 23:00:08 +0000590- The type of tp_free has been changed from "void (*)(PyObject *)" to
591 "void (*)(void *)".
592
593- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
594
Guido van Rossum0986d822002-04-08 01:38:42 +0000595- A type can now inherit its metatype from its base type. Previously,
596 when PyType_Ready() was called, if ob_type was found to be NULL, it
597 was always set to &PyType_Type; now it is set to base->ob_type,
598 where base is tp_base, defaulting to &PyObject_Type.
599
600- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
601
Neil Schemenauerc9abc1d2002-05-08 14:14:41 +0000602- The PyCore_* family of APIs have been removed.
Neil Schemenauer9d50d132002-03-22 17:06:59 +0000603
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000604- The "u#" parser marker will now pass through Unicode objects as-is
Marc-André Lemburg3e3eacb2002-01-09 16:21:27 +0000605 without going through the buffer API.
606
Martin v. Löwis7198a522002-01-01 19:59:11 +0000607- The enumerators of cmp_op have been renamed to use the prefix PyCmp_.
608
Tim Peters10a3bb52001-12-25 19:07:38 +0000609- An old #define of ANY as void has been removed from pyport.h. This
610 hasn't been used since Python's pre-ANSI days, and the #define has
611 been marked as obsolete since then. SF bug 495548 says it created
612 conflicts with other packages, so keeping it around wasn't harmless.
613
Tim Petersaf8446f2001-12-21 21:36:50 +0000614- Because Python's magic number scheme broke on January 1st, we decided
615 to stop Python development. Thanks for all the fish!
616
Tim Petersfb05db22002-03-11 00:24:00 +0000617- Some of us don't like fish, so we changed Python's magic number
Marc-André Lemburge92e0a92002-02-09 11:28:43 +0000618 scheme to a new one. See Python/import.c for details.
619
Tim Petersaf8446f2001-12-21 21:36:50 +0000620New platforms
621
Martin v. Löwisf90ae202002-06-11 06:22:31 +0000622- AtheOS is now supported.
623
Andrew MacIntyre161ad0e2002-08-04 07:25:58 +0000624- the EMX runtime environment on OS/2 is now supported.
625
Martin v. Löwisa6e97582002-01-01 18:41:33 +0000626- GNU/Hurd is now supported.
627
Tim Petersaf8446f2001-12-21 21:36:50 +0000628Tests
629
630Windows
631
Tim Peters08e72952002-04-16 20:48:01 +0000632- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
633 of that has been fixed in the installer (disabled Wise's "delete in-
634 use files" uninstall option).
635
Guido van Rossum181e41a2002-04-06 00:23:25 +0000636- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
637
Tim Peters33187922002-04-04 20:02:04 +0000638- The installer now installs Start menu shortcuts under (the local
639 equivalent of) "All Users" when doing an Admin install.
640
Tim Petersfb05db22002-03-11 00:24:00 +0000641- file.truncate([newsize]) now works on Windows for all newsize values.
642 It used to fail if newsize didn't fit in 32 bits, reflecting a
643 limitation of MS _chsize (which is no longer used).
644
Tim Petersab034fa2002-02-01 11:27:43 +0000645- os.waitpid() is now implemented for Windows, and can be used to block
646 until a specified process exits. This is similar to, but not exactly
647 the same as, os.waitpid() on POSIX systems. If you're waiting for
648 a specific process whose pid was obtained from one of the spawn()
649 functions, the same Python os.waitpid() code works across platforms.
Tim Peters33187922002-04-04 20:02:04 +0000650 See the docs for details. The docs were changed to clarify that
651 spawn functions return, and waitpid requires, a process handle on
652 Windows (not the same thing as a Windows process id).
Tim Petersab034fa2002-02-01 11:27:43 +0000653
Tim Peters11bd9942002-02-01 00:52:29 +0000654- New tempfile.TemporaryFile implementation for Windows: this doesn't
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000655 need a TemporaryFileWrapper wrapper anymore, and should be immune
Tim Peters11bd9942002-02-01 00:52:29 +0000656 to a nasty problem: before 2.3, if you got a temp file on Windows, it
657 got wrapped in an object whose close() method first closed the
658 underlying file, then deleted the file. This usually worked fine.
659 However, the spawn family of functions on Windows create (at a low C
660 level) the same set of open files in the spawned process Q as were
661 open in the spawning process P. If a temp file f was among them, then
662 doing f.close() in P first closed P's C-level file handle on f, but Q's
663 C-level file handle on f remained open, so the attempt in P to delete f
664 blew up with a "Permission denied" error (Windows doesn't allow
665 deleting open files). This was surprising, subtle, and difficult to
666 work around.
667
668- The os module now exports all the symbolic constants usable with the
669 low-level os.open() on Windows: the new constants in 2.3 are
670 O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
671 The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
672 O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
673 to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
674 (so specify both if you want both; note that neither is useful unless
675 specified with O_CREAT too).
676
Tim Petersaf8446f2001-12-21 21:36:50 +0000677Mac
678
679
Tim Peters909c0912001-12-14 23:16:18 +0000680What's New in Python 2.2 final?
681Release date: 21-Dec-2001
682===============================
683
684Type/class unification and new-style classes
685
Barry Warsaw52acb492001-12-21 20:04:22 +0000686- pickle.py, cPickle: allow pickling instances of new-style classes
687 with a custom metaclass.
688
Tim Peters909c0912001-12-14 23:16:18 +0000689Core and builtins
690
Barry Warsaw52acb492001-12-21 20:04:22 +0000691- weakref proxy object: when comparing, unwrap both arguments if both
692 are proxies.
693
Tim Peters909c0912001-12-14 23:16:18 +0000694Extension modules
695
Barry Warsaw52acb492001-12-21 20:04:22 +0000696- binascii.b2a_base64(): fix a potential buffer overrun when encoding
697 very short strings.
698
699- cPickle: the obscure "fast" mode was suspected of causing stack
700 overflows on the Mac. Hopefully fixed this by setting the recursion
701 limit much smaller. If the limit is too low (it only affects
702 performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
703 when compiling cPickle.c (or in pyconfig.h).
704
Tim Peters909c0912001-12-14 23:16:18 +0000705Library
706
Barry Warsaw52acb492001-12-21 20:04:22 +0000707- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
708 close or delete time).
709
710- rfc822.py: fixed a bug where the address '<>' was converted to None
711 instead of an empty string (also fixes the email.Utils module).
712
713- xmlrpclib.py: version 1.0.0; uses precision for doubles.
714
715- test suite: the pickle and cPickle tests were not executing any code
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000716 when run from the standard regression test.
Barry Warsaw52acb492001-12-21 20:04:22 +0000717
Tim Peters909c0912001-12-14 23:16:18 +0000718Tools/Demos
719
720Build
721
722C API
723
724New platforms
725
726Tests
727
728Windows
729
Barry Warsaw52acb492001-12-21 20:04:22 +0000730- distutils package: fixed broken Windows installers (bdist_wininst).
731
732- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
733 instances are deleted at process exit time.
734
735- socket.py: prevent mysterious warnings when socket instances are
736 deleted at process exit time.
737
738- posixmodule.c: fix a Windows crash with stat() of a filename ending
739 in backslash.
740
Tim Peters909c0912001-12-14 23:16:18 +0000741Mac
742
Barry Warsaw52acb492001-12-21 20:04:22 +0000743- The Carbon toolbox modules have been upgraded to Universal Headers
744 3.4, and experimental CoreGraphics and CarbonEvents modules have
745 been added. All only for framework-enabled MacOSX.
746
Tim Peters909c0912001-12-14 23:16:18 +0000747
Tim Peters6272dfd2001-12-13 19:34:00 +0000748What's New in Python 2.2c1?
749Release date: 14-Dec-2001
Tim Petersb3c9af12001-11-17 00:21:57 +0000750===========================
751
752Type/class unification and new-style classes
753
Barry Warsaw06557452001-12-14 20:47:12 +0000754- Guido's tutorial introduction to the new type/class features has
755 been extensively updated. See
756
757 http://www.python.org/2.2/descrintro.html
758
759 That remains the primary documentation in this area.
760
Guido van Rossum33bab012001-12-05 22:45:48 +0000761- Fixed a leak: instance variables declared with __slots__ were never
762 deleted!
763
Guido van Rossum4b800852001-12-03 00:54:52 +0000764- The "delete attribute" method of descriptor objects is called
765 __delete__, not __del__. In previous releases, it was mistakenly
766 called __del__, which created an unfortunate overloading condition
767 with finalizers. (The "get attribute" and "set attribute" methods
768 are still called __get__ and __set__, respectively.)
769
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000770- Some subtle issues with the super built-in were fixed:
771
772 (a) When super itself is subclassed, its __get__ method would still
773 return an instance of the base class (i.e., of super).
774
775 (b) super(C, C()).__class__ would return C rather than super. This
776 is confusing. To fix this, I decided to change the semantics of
777 super so that it only applies to code attributes, not to data
778 attributes. After all, overriding data attributes is not
779 supported anyway.
780
781 (c) The __get__ method didn't check whether the argument was an
782 instance of the type used in creation of the super instance.
783
Guido van Rossumcd7b7d62001-12-04 21:02:07 +0000784- Previously, hash() of an instance of a subclass of a mutable type
785 (list or dictionary) would return some value, rather than raising
786 TypeError. This has been fixed. Also, directly calling
787 dict.__hash__ and list.__hash__ now raises the same TypeError
788 (previously, these were the same as object.__hash__).
Guido van Rossumcdbbd0a2001-12-03 15:46:59 +0000789
Guido van Rossumd331cb52001-12-05 19:46:42 +0000790- New-style objects now support deleting their __dict__. This is for
791 all intents and purposes equivalent to assigning a brand new empty
792 dictionary, but saves space if the object is not used further.
793
Tim Petersb3c9af12001-11-17 00:21:57 +0000794Core and builtins
795
Tim Peters3caca232001-12-06 06:23:26 +0000796- -Qnew now works as documented in PEP 238: when -Qnew is passed on
797 the command line, all occurrences of "/" use true division instead
798 of classic division. See the PEP for details. Note that "all"
799 means all instances in library and 3rd-party modules, as well as in
800 your own code. As the PEP says, -Qnew is intended for use only in
801 educational environments with control over the libraries in use.
Tim Petersbf72fe22001-12-11 21:43:14 +0000802 Note that test_coercion.py in the standard Python test suite fails
803 under -Qnew; this is expected, and won't be repaired until true
804 division becomes the default (in the meantime, test_coercion is
805 testing the current rules).
Tim Peters3caca232001-12-06 06:23:26 +0000806
Fred Drake6c01e252001-12-14 17:08:12 +0000807- complex() now only allows the first argument to be a string
808 argument, and raises TypeError if either the second arg is a string
809 or if the second arg is specified when the first is a string.
810
Tim Petersb3c9af12001-11-17 00:21:57 +0000811Extension modules
812
Martin v. Löwis560da622001-11-24 09:24:51 +0000813- gc.get_referents was renamed to gc.get_referrers.
814
Tim Petersb3c9af12001-11-17 00:21:57 +0000815Library
816
Tim Peters25059d32001-12-07 20:35:43 +0000817- Functions in the os.spawn() family now release the global interpreter
818 lock around calling the platform spawn. They should always have done
819 this, but did not before 2.2c1. Multithreaded programs calling
820 an os.spawn function with P_WAIT will no longer block all Python threads
821 until the spawned program completes. It's possible that some programs
822 relies on blocking, although more likely by accident than by design.
823
Martin v. Löwis3a89b2b2001-11-25 14:35:58 +0000824- webbrowser defaults to netscape.exe on OS/2 now.
825
Martin v. Löwis652e1912001-11-25 14:50:56 +0000826- Tix.ResizeHandle exposes detach_widget, hide, and show.
827
Martin v. Löwis714d2e22001-12-02 12:26:03 +0000828- The charset alias windows_1252 has been added.
829
Barry Warsaw06557452001-12-14 20:47:12 +0000830- types.StringTypes is a tuple containing the defined string types;
831 usually this will be (str, unicode), but if Python was compiled
832 without Unicode support it will be just (str,).
833
834- The pulldom and minidom modules were synchronized to PyXML.
835
Tim Petersb3c9af12001-11-17 00:21:57 +0000836Tools/Demos
837
Barry Warsaw06557452001-12-14 20:47:12 +0000838- A new script called Tools/scripts/google.py was added, which fires
839 off a search on Google.
840
Tim Petersb3c9af12001-11-17 00:21:57 +0000841Build
842
Barry Warsaw06557452001-12-14 20:47:12 +0000843- Note that release builds of Python should arrange to define the
844 preprocessor symbol NDEBUG on the command line (or equivalent).
845 In the 2.2 pre-release series we tried to define this by magic in
846 Python.h instead, but it proved to cause problems for extension
847 authors. The Unix, Windows and Mac builds now all define NDEBUG in
848 release builds via cmdline (or equivalent) instead. Ports to
849 other platforms should do likewise.
850
Jack Jansen1999ef42001-12-06 21:47:20 +0000851- It is no longer necessary to use --with-suffix when building on a
852 case-insensitive file system (such as Mac OS X HFS+). In the build
853 directory an extension is used, but not in the installed python.
854
Tim Petersb3c9af12001-11-17 00:21:57 +0000855C API
856
Tim Petersf582b822001-12-11 18:51:08 +0000857- New function PyDict_MergeFromSeq2() exposes the builtin dict
858 constructor's logic for updating a dictionary from an iterable object
859 producing key-value pairs.
860
Tim Peterscffed4b2001-11-29 03:26:37 +0000861- PyArg_ParseTupleAndKeywords() requires that the number of entries in
Tim Petersf582b822001-12-11 18:51:08 +0000862 the keyword list equal the number of argument specifiers. This
Tim Peterscffed4b2001-11-29 03:26:37 +0000863 wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
864 dump core in some bad cases. This has been repaired. As a result,
865 PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
866 previously went unchallenged.
867
Tim Petersb3c9af12001-11-17 00:21:57 +0000868New platforms
869
870Tests
871
872Windows
873
874Mac
875
Jack Jansenffa260f2001-12-06 21:14:00 +0000876- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
877 without any trailing digits.
Tim Petersb3c9af12001-11-17 00:21:57 +0000878
Barry Warsaw06557452001-12-14 20:47:12 +0000879- Changed logic for finding python home in Mac OS X framework Pythons.
880 Now sys.executable points to the executable again, in stead of to
881 the shared library. The latter is used only for locating the python
882 home.
883
884
Tim Peters84362bc2001-10-19 17:55:30 +0000885What's New in Python 2.2b2?
Tim Peters76f7fe32001-11-15 20:02:21 +0000886Release date: 16-Nov-2001
Tim Peters84362bc2001-10-19 17:55:30 +0000887===========================
888
889Type/class unification and new-style classes
890
Guido van Rossum3d27df02001-11-15 20:27:54 +0000891- Multiple inheritance mixing new-style and classic classes in the
892 list of base classes is now allowed, so this works now:
Tim Peters76f7fe32001-11-15 20:02:21 +0000893
894 class Classic: pass
Guido van Rossum3d27df02001-11-15 20:27:54 +0000895 class Mixed(Classic, object): pass
Tim Peters76f7fe32001-11-15 20:02:21 +0000896
897 The MRO (method resolution order) for each base class is respected
898 according to its kind, but the MRO for the derived class is computed
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000899 using new-style MRO rules if any base class is a new-style class.
Tim Peters76f7fe32001-11-15 20:02:21 +0000900 This needs to be documented.
901
Tim Petersa427a2b2001-10-29 22:25:45 +0000902- The new builtin dictionary() constructor, and dictionary type, have
903 been renamed to dict. This reflects a decade of common usage.
904
Guido van Rossum3fc08d22001-11-15 20:33:10 +0000905- dict() now accepts an iterable object producing 2-sequences. For
906 example, dict(d.items()) == d for any dictionary d. The argument,
907 and the elements of the argument, can be any iterable objects.
908
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +0000909- New-style classes can now have a __del__ method, which is called
910 when the instance is deleted (just like for classic classes).
911
Guido van Rossum12d955c2001-10-26 14:56:06 +0000912- Assignment to object.__dict__ is now possible, for objects that are
913 instances of new-style classes that have a __dict__ (unless the base
914 class forbids it).
915
Guido van Rossumc8e56452001-10-22 00:43:43 +0000916- Methods of built-in types now properly check for keyword arguments
917 (formerly these were silently ignored). The only built-in methods
918 that take keyword arguments are __call__, __init__ and __new__.
919
Guido van Rossum86443212001-10-27 22:28:54 +0000920- The socket function has been converted to a type; see below.
921
Tim Peters84362bc2001-10-19 17:55:30 +0000922Core and builtins
923
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000924- Assignment to __debug__ raises SyntaxError at compile-time. This
925 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
Barry Warsaw012852b2001-11-16 16:17:27 +0000926 (see below) says.
Jeremy Hylton249aaed2001-11-09 21:06:24 +0000927
Guido van Rossum12d955c2001-10-26 14:56:06 +0000928- Clarified the error messages for unsupported operands to an operator
929 (like 1 + '').
930
Tim Peters84362bc2001-10-19 17:55:30 +0000931Extension modules
932
Tim Peters5ebfd362001-11-13 23:11:19 +0000933- mmap has a new keyword argument, "access", allowing a uniform way for
934 both Windows and Unix users to create read-only, write-through and
935 copy-on-write memory mappings. This was previously possible only on
936 Unix. A new keyword argument was required to support this in a
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +0000937 uniform way because the mmap() signatures had diverged across
Tim Peters5ebfd362001-11-13 23:11:19 +0000938 platforms. Thanks to Jay T Miller for repairing this!
939
Tim Peters169ded02001-11-03 19:57:21 +0000940- By default, the gc.garbage list now contains only those instances in
941 unreachable cycles that have __del__ methods; in 2.1 it contained all
942 instances in unreachable cycles. "Instances" here has been generalized
943 to include instances of both new-style and old-style classes.
944
Guido van Rossum12d955c2001-10-26 14:56:06 +0000945- The socket module defines a new method for socket objects,
946 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +0000947 send() until all data has been sent. Also, the socket function has
948 been converted to a subclassable type, like list and tuple (etc.)
949 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +0000950
951- Various bugfixes to the curses module. There is now a test suite
952 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000953
Guido van Rossum692adf12001-10-30 03:03:03 +0000954- binascii.b2a_base64 no longer places an arbitrary restriction of 57
955 bytes on its input.
956
Tim Peters84362bc2001-10-19 17:55:30 +0000957Library
958
Tim Peters5ebfd362001-11-13 23:11:19 +0000959- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +0000960 convenience function.
961
Tim Peters75335872001-11-03 19:35:43 +0000962- Symbolic group names in regular expressions must be unique. For
963 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
964 single name can't mean both "group 1" and "group 2" simultaneously.
Barry Warsaw012852b2001-11-16 16:17:27 +0000965 Python 2.2 detects this error at regexp compilation time;
966 previously, the error went undetected, and results were
967 unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
968 pattern.subn() methods have been rewritten in C. Also, an
969 experimental function/method finditer() has been added, which works
970 like findall() but returns an iterator.
Tim Peters75335872001-11-03 19:35:43 +0000971
Martin v. Löwisb7b32602001-11-02 23:48:20 +0000972- Tix exposes more commands through the classes DirSelectBox,
973 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
974 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
975 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
976
Tim Peters98791af2001-10-23 01:59:54 +0000977- Traceback objects are now scanned by cyclic garbage collection, so
978 cycles created by casual use of sys.exc_info() no longer cause
979 permanent memory leaks (provided garbage collection is enabled).
980
Guido van Rossum49192142001-10-24 20:51:44 +0000981- os.extsep -- a new variable needed by the RISCOS support. It is the
982 separator used by extensions, and is '.' on all platforms except
983 RISCOS, where it is '/'. There is no need to use this variable
984 unless you have a masochistic desire to port your code to RISCOS.
985
Barry Warsaw012852b2001-11-16 16:17:27 +0000986- mimetypes.py has optional support for non-standard, but commonly
987 found types. guess_type() and guess_extension() now accept an
988 optional `strict' flag, defaulting to true, which controls whether
989 recognize non-standard types or not. A few non-standard types we
990 know about have been added. Also, when run as a script, there are
991 new -l and -e options.
992
993- statcache is now deprecated.
994
995- email.Utils.formatdate() now produces the preferred RFC 2822 style
996 dates with numeric timezones (it used to produce obsolete dates
997 hard coded to "GMT" timezone). An optional `localtime' flag is
998 added to produce dates in the local timezone, with daylight savings
999 time properly taken into account.
1000
1001- In pickle and cPickle, instead of masking errors in load() by
1002 transforming them into SystemError, we let the original exception
1003 propagate out. Also, implement support for __safe_for_unpickling__
1004 in pickle, as it already was supported in cPickle.
1005
Tim Peters84362bc2001-10-19 17:55:30 +00001006Tools/Demos
1007
1008Build
1009
Barry Warsaw012852b2001-11-16 16:17:27 +00001010- The dbm module is built using libdb1 if available. The bsddb module
1011 is built with libdb3 if available.
1012
1013- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
1014
Tim Peters84362bc2001-10-19 17:55:30 +00001015C API
1016
Tim Peters1fc240e2001-10-26 05:06:50 +00001017- New function PySequence_Fast_GET_SIZE() returns the size of a non-
1018 NULL result from PySequence_Fast(), more quickly than calling
1019 PySequence_Size().
1020
Barry Warsaw012852b2001-11-16 16:17:27 +00001021- New argument unpacking function PyArg_UnpackTuple() added.
1022
1023- New functions PyObject_CallFunctionObjArgs() and
1024 PyObject_CallMethodObjArgs() have been added to make it more
1025 convenient and efficient to call functions and methods from C.
1026
1027- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
1028 possible that this will propagate errors it didn't before.
1029
1030- New function PyObject_CheckReadBuffer(), which returns true if its
1031 argument supports the single-segment readable buffer interface.
1032
Tim Peters84362bc2001-10-19 17:55:30 +00001033New platforms
1034
Guido van Rossum86443212001-10-27 22:28:54 +00001035- We've finally confirmed that this release builds on HP-UX 11.00,
1036 *with* threads, and passes the test suite.
1037
Tim Peters7a33d8b2001-11-05 02:51:07 +00001038- Thanks to a series of patches from Michael Muller, Python may build
1039 again under OS/2 Visual Age C++.
1040
Guido van Rossum49192142001-10-24 20:51:44 +00001041- Updated RISCOS port by Dietmar Schwertberger.
1042
Tim Peters84362bc2001-10-19 17:55:30 +00001043Tests
1044
Andrew M. Kuchling15e03532001-10-22 16:37:10 +00001045- Added a test script for the curses module. It isn't run automatically;
1046 regrtest.py must be run with '-u curses' to enable it.
1047
Tim Peters84362bc2001-10-19 17:55:30 +00001048Windows
1049
Barry Warsaw012852b2001-11-16 16:17:27 +00001050Mac
1051
1052- PythonScript has been moved to unsupported and is slated to be
1053 removed completely in the next release.
1054
1055- It should now be possible to build applets that work on both OS9 and
1056 OSX.
1057
1058- The core is now linked with CoreServices not Carbon; as a side
1059 result, default 8bit encoding on OSX is now ASCII.
1060
1061- Python should now build on OSX 10.1.1
1062
Tim Peters84362bc2001-10-19 17:55:30 +00001063
Tim Petersabf925f2001-09-28 21:53:42 +00001064What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +00001065Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +00001066===========================
1067
1068Type/class unification and new-style classes
1069
Guido van Rossum687ae002001-10-15 22:03:32 +00001070- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001071 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +00001072 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001073 remains: the __dict__ of a new-style class is a read-only proxy; you
1074 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +00001075 __defined__ attribute of new-style types no longer exists, for lack
1076 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +00001077 future a __cache__ may be resurrected with a similar function, if I
1078 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +00001079
Tim Peters1c9ca872001-10-04 06:43:12 +00001080- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
1081 always returned None, even when there was a class docstring).
1082
1083- doctest now finds and runs docstrings attached to new-style classes,
1084 class methods, static methods, and properties.
1085
Guido van Rossum9074ef62001-10-16 21:34:49 +00001086Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +00001087
Guido van Rossuma8bcf802001-10-15 15:53:58 +00001088- A very subtle syntactical pitfall in list comprehensions was fixed.
1089 For example: [a+b for a in 'abc', for b in 'def']. The comma in
1090 this example is a mistake. Previously, this would silently let 'a'
1091 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
1092 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
1093 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
1094 Note that [a for a in <singleton>] is a convoluted way to say
1095 [<singleton>] anyway, so it's not like any expressiveness is lost.
1096
Guido van Rossum9074ef62001-10-16 21:34:49 +00001097- getattr(obj, name, default) now only catches AttributeError, as
1098 documented, rather than returning the default value for all
1099 exceptions (which could mask bugs in a __getattr__ hook, for
1100 example).
1101
Fred Drakecb7a6b52001-10-22 18:41:51 +00001102- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +00001103 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001104 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +00001105 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +00001106
Guido van Rossum1c486092001-10-19 02:05:35 +00001107- unicode(obj) now behaves more like str(obj), accepting arbitrary
1108 objects, and calling a __unicode__ method if it exists.
1109 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +00001110 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +00001111
Barry Warsawf6fb1712001-10-19 05:35:40 +00001112- isinstance() now allows any object as the first argument and a
1113 class, a type or something with a __bases__ tuple attribute for the
1114 second argument. The second argument may also be a tuple of a
1115 class, type, or something with __bases__, in which case isinstance()
1116 will return true if the first argument is an instance of any of the
1117 things contained in the second argument tuple. E.g.
1118
1119 isinstance(x, (A, B))
1120
1121 returns true if x is an instance of A or B.
1122
Guido van Rossum9074ef62001-10-16 21:34:49 +00001123Extension modules
1124
1125- thread.start_new_thread() now returns the thread ID (previously None).
1126
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001127- binascii has now two quopri support functions, a2b_qp and b2a_qp.
1128
Guido van Rossumc524d952001-10-19 01:31:59 +00001129- readline now supports setting the startup_hook and the
1130 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +00001131
Guido van Rossumc524d952001-10-19 01:31:59 +00001132- os and posix supports chroot(), setgroups() and unsetenv() where
1133 available. The stat(), fstat(), statvfs() and fstatvfs() functions
1134 now return "pseudo-sequences" -- the various fields can now be
1135 accessed as attributes (e.g. os.stat("/").st_mtime) but for
1136 backwards compatibility they also behave as a fixed-length sequence.
1137 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +00001138 attributes.
1139
1140- time: localtime(), gmtime() and strptime() now return a
1141 pseudo-sequence similar to the os.stat() return value, with
1142 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +00001143
Guido van Rossum9074ef62001-10-16 21:34:49 +00001144- Decompression objects in the zlib module now accept an optional
1145 second parameter to decompress() that specifies the maximum amount
1146 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +00001147
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001148- optional SSL support in the socket module now exports OpenSSL
1149 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
1150 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +00001151 automatically seed its PRNG. Also, the keyfile and certfile
1152 arguments to socket.ssl() are now optional.
1153
1154- posixmodule (and by extension, the os module on POSIX platforms) now
1155 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +00001156
Guido van Rossum9074ef62001-10-16 21:34:49 +00001157Library
Guido van Rossum3c288632001-10-16 21:13:49 +00001158
Tim Peters7402f792001-10-02 03:53:41 +00001159- doctest now excludes functions and classes not defined by the module
1160 being tested, thanks to Tim Hochberg.
1161
Fred Drakecb7a6b52001-10-22 18:41:51 +00001162- HotShot, a new profiler implemented using a C-based callback, has
1163 been added. This substantially reduces the overhead of profiling,
1164 but it is still quite preliminary. Support modules and
1165 documentation will be added in upcoming releases (before 2.2 final).
1166
Guido van Rossumc4b09b42001-10-04 10:19:00 +00001167- profile now produces correct output in situations where an exception
1168 raised in Python is cleared by C code (e.g. hasattr()). This used
1169 to cause wrong output, including spurious claims of recursive
1170 functions and attribution of time spent to the wrong function.
1171
Tim Peters0a1fc4e2001-10-07 03:12:08 +00001172 The code and documentation for the derived OldProfile and HotProfile
1173 profiling classes was removed. The code hasn't worked for years (if
1174 you tried to use them, they raised exceptions). OldProfile
1175 intended to reproduce the behavior of the profiler Python used more
1176 than 7 years ago, and isn't interesting anymore. HotProfile intended
1177 to provide a faster profiler (but producing less information), and
1178 that's a worthy goal we intend to meet via a different approach (but
1179 without losing information).
1180
Tim Peterscce092d2001-10-09 05:31:56 +00001181- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +00001182 a much better system-specific calibration constant. The constant can
1183 now be specified in an instance constructor, or as a Profile class or
1184 instance variable, instead of by editing profile.py's source code.
1185 Calibration must still be done manually (see the docs for the profile
1186 module).
1187
1188 Note that Profile.calibrate() must be overriden by subclasses.
1189 Improving the accuracy required exploiting detailed knowledge of
1190 profiler internals; the earlier method abstracted away the details
1191 and measured a simplified model instead, but consequently computed
1192 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +00001193
Martin v. Löwis16dc7f42001-09-30 20:32:11 +00001194- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +00001195 which indicates whether output is intended for the header 'Q'
1196 encoding.
1197
Guido van Rossuma5343cc2001-10-18 18:02:07 +00001198- The SocketServer.ThreadingMixIn class now closes the request after
1199 finish_request() returns. (Not when it errors out though.)
1200
Barry Warsawf6fb1712001-10-19 05:35:40 +00001201- The nntplib module's NNTP.body() method has grown a `file' argument
1202 to allow saving the message body to a file.
1203
1204- The email package has added a class email.Parser.HeaderParser which
1205 only parses headers and does not recurse into the message's body.
1206 Also, the module/class MIMEAudio has been added for representing
1207 audio data (contributed by Anthony Baxter).
1208
1209- ftplib should be able to handle files > 2GB.
1210
1211- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
1212 ON, and OFF.
1213
Fred Drakecb7a6b52001-10-22 18:41:51 +00001214- xml.dom.minidom NodeList objects now support the length attribute
1215 and item() method as required by the DOM specifications.
1216
Guido van Rossumed554f62001-10-02 23:15:37 +00001217Tools/Demos
1218
1219- Demo/dns was removed. It no longer serves any purpose; a package
1220 derived from it is now maintained by Anthony Baxter, see
1221 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +00001222
Barry Warsawf6fb1712001-10-19 05:35:40 +00001223- The freeze tool has been made more robust, and two new options have
1224 been added: -X and -E.
1225
Tim Petersabf925f2001-09-28 21:53:42 +00001226Build
1227
Barry Warsawf6fb1712001-10-19 05:35:40 +00001228- configure will use CXX in LINKCC if CXX is used to build main() and
1229 the system requires to link a C++ main using the C++ compiler.
1230
Tim Petersabf925f2001-09-28 21:53:42 +00001231C API
1232
Guido van Rossum6c4bce32001-10-18 19:20:25 +00001233- The documentation for the tp_compare slot is updated to require that
1234 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
1235 not correct. This is not yet enforced but will be enforced in
1236 Python 2.3; even later, we may use -2 to indicate errors and +2 for
1237 "NotImplemented". Right now, -1 should be used for an error return.
1238
Tim Petersd38b1c72001-09-30 05:09:37 +00001239- PyLong_AsLongLong() now accepts int (as well as long) arguments.
1240 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
1241 as long) arguments.
1242
Guido van Rossum3c288632001-10-16 21:13:49 +00001243- PyThread_start_new_thread() now returns a long int giving the thread
1244 ID, if one can be calculated; it returns -1 for error, 0 if no
1245 thread ID is calculated (this is an incompatible change, but only
1246 the thread module used this API). This code has only really been
1247 tested on Linux and Windows; other platforms please beware (and
1248 report any bugs or strange behavior).
1249
Guido van Rossum1c486092001-10-19 02:05:35 +00001250- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
1251 input.
1252
Tim Petersabf925f2001-09-28 21:53:42 +00001253New platforms
1254
1255Tests
1256
1257Windows
1258
Tim Peters04cf1d32001-10-09 22:39:40 +00001259- Installer: If you install IDLE, and don't disable file-extension
1260 registration, a new "Edit with IDLE" context (right-click) menu entry
1261 is created for .py and .pyw files.
1262
Tim Peters1ce3cf72001-10-01 17:58:40 +00001263- The signal module now supports SIGBREAK on Windows, thanks to Steven
1264 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
1265 action remains to call Win32 ExitProcess(). This can be changed via
1266 signal.signal(). For example:
1267
1268 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
1269 # (SIGINT) behavior.
1270 import signal
1271 signal.signal(signal.SIGBREAK,
1272 signal.default_int_handler)
1273
1274 try:
1275 while 1:
1276 pass
1277 except KeyboardInterrupt:
1278 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
1279 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
1280 # program without the possibility for any Python-level cleanup).
1281 print "Clean exit"
1282
Tim Petersabf925f2001-09-28 21:53:42 +00001283
Tim Petersb07352e2001-09-08 01:25:47 +00001284What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001285Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +00001286===========================
1287
Guido van Rossum808eea72001-09-25 04:15:41 +00001288Type/class unification and new-style classes
1289
1290- pydoc and inspect are now aware of new-style classes;
1291 e.g. help(list) at the interactive prompt now shows proper
1292 documentation for all operations on list objects.
1293
1294- Applications using Jim Fulton's ExtensionClass module can now safely
1295 be used with Python 2.2. In particular, Zope 2.4.1 now works with
1296 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
1297 examples also work again. It is hoped that Gtk and Boost also work
1298 with 2.2a4 and beyond. (If you can confirm this, please write
1299 webmaster@python.org; if there are still problems, please open a bug
1300 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +00001301
Tim Peters66c1a522001-09-24 21:17:50 +00001302- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001303 These map to read-only attributes 'fget', 'fset', 'fdel', and '__doc__'
Tim Peters66c1a522001-09-24 21:17:50 +00001304 in the constructed property object. fget, fset and fdel weren't
1305 discoverable from Python in 2.2a3. __doc__ is new, and allows to
1306 associate a docstring with a property.
1307
Guido van Rossum808eea72001-09-25 04:15:41 +00001308- Comparison overloading is now more completely implemented. For
1309 example, a str subclass instance can properly be compared to a str
1310 instance, and it can properly overload comparison. Ditto for most
1311 other built-in object types.
1312
1313- The repr() of new-style classes has changed; instead of <type
1314 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
1315 *except* for built-in types, which are still rendered as <type
1316 'Foo'> (to avoid upsetting existing code that might parse or
1317 otherwise rely on repr() of certain type objects).
1318
1319- The repr() of new-style objects is now always <Foo object at XXX>;
1320 previously, it was sometimes <Foo instance at XXX>.
1321
1322- For new-style classes, what was previously called __getattr__ is now
1323 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001324 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +00001325 one in classic classes is defined which is called only if regular
1326 attribute access raises AttributeError; to catch *all* attribute
1327 access, you can use __getattribute__ (for new-style classes). If
1328 both are defined, __getattribute__ is called first, and if it raises
1329 AttributeError, __getattr__ is called.
1330
1331- The __class__ attribute of new-style objects can be assigned to.
1332 The new class must have the same C-level object layout as the old
1333 class.
1334
1335- The builtin file type can be subclassed now. In the usual pattern,
1336 "file" is the name of the builtin type, and file() is a new builtin
1337 constructor, with the same signature as the builtin open() function.
1338 file() is now the preferred way to open a file.
1339
1340- Previously, __new__ would only see sequential arguments passed to
1341 the type in a constructor call; __init__ would see both sequential
1342 and keyword arguments. This made no sense whatsoever any more, so
1343 now both __new__ and __init__ see all arguments.
1344
1345- Previously, hash() applied to an instance of a subclass of str or
1346 unicode always returned 0. This has been repaired.
1347
1348- Previously, an operation on an instance of a subclass of an
1349 immutable type (int, long, float, complex, tuple, str, unicode),
1350 where the subtype didn't override the operation (and so the
1351 operation was handled by the builtin type), could return that
1352 instance instead a value of the base type. For example, if s was of
Andrew M. Kuchling21b23b02002-05-07 20:58:03 +00001353 a str subclass type, s[:] returned s as-is. Now it returns a str
Guido van Rossum808eea72001-09-25 04:15:41 +00001354 with the same value as s.
1355
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001356- Provisional support for pickling new-style objects has been added.
1357
Guido van Rossum808eea72001-09-25 04:15:41 +00001358Core
1359
Tim Peters2c9aa5e2001-09-23 04:06:05 +00001360- file.writelines() now accepts any iterable object producing strings.
1361
Marc-André Lemburgaefd7662001-09-20 12:59:37 +00001362- PyUnicode_FromEncodedObject() now works very much like
1363 PyObject_Str(obj) in that it tries to use __str__/tp_str
1364 on the object if the object is not a string or buffer. This
1365 makes unicode() behave like str() when applied to non-string/buffer
1366 objects.
1367
Andrew M. Kuchling51c18162001-10-22 01:47:26 +00001368- PyFile_WriteObject now passes Unicode objects to the file's write
1369 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +00001370 of a print statement must support Unicode objects, i.e. they must
1371 at least convert them into ASCII strings.
1372
Guido van Rossum624c8af2001-09-18 15:21:04 +00001373- Thread scheduling on Solaris should be improved; it is no longer
1374 necessary to insert a small sleep at the start of a thread in order
1375 to let other runnable threads be scheduled.
1376
Tim Petersb07352e2001-09-08 01:25:47 +00001377Library
1378
Marc-André Lemburgbf990172001-09-27 14:17:33 +00001379- StringIO.StringIO instances and cStringIO.StringIO instances support
1380 read character buffer compatible objects for their .write() methods.
1381 These objects are converted to strings and then handled as such
1382 by the instances.
1383
Barry Warsaw2f600732001-09-24 04:28:10 +00001384- The "email" package has been added. This is basically a port of the
1385 mimelib package <http://sf.net/projects/mimelib> with API changes
1386 and some implementations updated to use iterators and generators.
1387
Tim Peters8a9c2842001-09-22 21:30:22 +00001388- difflib.ndiff() and difflib.Differ.compare() are generators now. This
1389 restores the ability of Tools/scripts/ndiff.py to start producing output
1390 before the entire comparison is complete.
1391
Barry Warsaw58b072d2001-09-22 04:44:21 +00001392- StringIO.StringIO instances and cStringIO.StringIO instances support
1393 iteration just like file objects (i.e. their .readline() method is
1394 called for each iteration until it returns an empty string).
1395
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +00001396- The codecs module has grown four new helper APIs to access
1397 builtin codecs: getencoder(), getdecoder(), getreader(),
1398 getwriter().
1399
Guido van Rossum624c8af2001-09-18 15:21:04 +00001400- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
1401 simplifies writing XML RPC servers.
1402
Barry Warsaw647d5e82001-09-28 17:01:02 +00001403- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +00001404 after interpretation of symbolic links. On non-Unix systems, this
1405 is an alias for os.path.abspath().
1406
Tim Peters16a77ad2001-09-08 04:00:12 +00001407- operator.indexOf() (PySequence_Index() in the C API) now works with any
1408 iterable object.
1409
Guido van Rossum624c8af2001-09-18 15:21:04 +00001410- smtplib now supports various authentication and security features of
1411 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001412
Guido van Rossum624c8af2001-09-18 15:21:04 +00001413- hmac: a new module implementing keyed hashing for message
1414 authentication.
1415
1416- mimetypes now recognizes more extensions and file types. At the
1417 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +00001418
Guido van Rossum624c8af2001-09-18 15:21:04 +00001419- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001420 Python 2.2 bytecode generation. It has also been promoted from a
1421 Tool to a standard library package. (Tools/compiler still exists as
1422 a sample driver.)
1423
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +00001424Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +00001425
Tim Petersb07352e2001-09-08 01:25:47 +00001426Build
1427
Guido van Rossum624c8af2001-09-18 15:21:04 +00001428- Large file support (LFS) is now automatic when the platform supports
1429 it; no more manual configuration tweaks are needed. On Linux, at
1430 least, it's possible to have a system whose C library supports large
1431 files but whose kernel doesn't; in this case, large file support is
1432 still enabled but doesn't do you any good unless you upgrade your
1433 kernel or share your Python executable with another system whose
1434 kernel has large file support.
1435
1436- The configure script now supplies plausible defaults in a
1437 cross-compilation environment. This doesn't mean that the supplied
1438 values are always correct, or that cross-compilation now works
1439 flawlessly -- but it's a first step (and it shuts up most of
1440 autoconf's warnings about AC_TRY_RUN).
1441
1442- The Unix build is now a bit less chatty, courtesy of the parser
1443 generator. The build is completely silent (except for errors) when
1444 using "make -s", thanks to a -q option to setup.py.
1445
Tim Petersb07352e2001-09-08 01:25:47 +00001446C API
1447
Guido van Rossum624c8af2001-09-18 15:21:04 +00001448- The "structmember" API now supports some new flag bits to deny read
1449 and/or write access to attributes in restricted execution mode.
1450
Tim Petersb07352e2001-09-08 01:25:47 +00001451New platforms
1452
Guido van Rossum624c8af2001-09-18 15:21:04 +00001453- Compaq's iPAQ handheld, running the "familiar" Linux distribution
1454 (http://familiar.handhelds.org).
1455
Tim Petersb07352e2001-09-08 01:25:47 +00001456Tests
1457
Tim Peters8a9c2842001-09-22 21:30:22 +00001458- The "classic" standard tests, which work by comparing stdout to
1459 an expected-output file under Lib/test/output/, no longer stop at
1460 the first mismatch. Instead the test is run to completion, and a
1461 variant of ndiff-style comparison is used to report all differences.
1462 This is much easier to understand than the previous style of reporting.
1463
1464- The unittest-based standard tests now use regrtest's test_main()
1465 convention, instead of running as a side-effect of merely being
1466 imported. This allows these tests to be run in more natural and
1467 flexible ways as unittests, outside the regrtest framework.
1468
1469- regrtest.py is much better integrated with unittest and doctest now,
1470 especially in regard to reporting errors.
1471
Tim Petersb07352e2001-09-08 01:25:47 +00001472Windows
1473
Guido van Rossum624c8af2001-09-18 15:21:04 +00001474- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +00001475 that support it (NTFS under Windows 2000). See "What's New in
1476 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +00001477
Tim Petersb07352e2001-09-08 01:25:47 +00001478
Tim Petersedc99312001-08-22 21:36:50 +00001479What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001480Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +00001481===========================
1482
1483Core
1484
Tim Peters9fffa3e2001-09-04 05:14:19 +00001485- Conversion of long to float now raises OverflowError if the long is too
1486 big to represent as a C double.
1487
Tim Peters32f453e2001-09-03 08:35:41 +00001488- The 3-argument builtin pow() no longer allows a third non-None argument
1489 if either of the first two arguments is a float, or if both are of
1490 integer types and the second argument is negative (in which latter case
1491 the arguments are converted to float, so this is really the same
1492 restriction).
1493
Tim Peters5d2b77c2001-09-03 05:47:38 +00001494- The builtin dir() now returns more information, and sometimes much
1495 more, generally naming all attributes of an object, and all attributes
1496 reachable from the object via its class, and from its class's base
1497 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
1498 an empty list. In 2.2a3,
1499
1500 >>> dir([])
1501 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
1502 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
1503 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
1504 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
1505 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
1506 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
1507 'reverse', 'sort']
1508
1509 dir(module) continues to return only the module's attributes, though.
1510
Tim Petersbdee63f2001-09-02 03:40:59 +00001511- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +00001512 than raising OverflowError. This is a partial implementation of PEP
1513 237. You can use -Wdefault::OverflowWarning to enable a warning for
1514 this situation, and -Werror::OverflowWarning to revert to the old
1515 OverflowError exception.
1516
Guido van Rossum61c345f2001-09-04 03:26:15 +00001517- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +00001518 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001519 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
1520 -Qold, meaning the / operator has its classic meaning and no
1521 warnings are issued. Using -Qwarn issues a run-time warning about
1522 all uses of classic division for int and long arguments; -Qwarnall
1523 also warns about classic division for float and complex arguments
Tim Peters3caca232001-12-06 06:23:26 +00001524 (for use with fixdiv.py).
1525 [Note: the remainder of this paragraph (preserved below) became
1526 obsolete in 2.2c1 -- -Qnew has global effect in 2.2]
1527 <obsolete>
1528 Using -Qnew is questionable; it turns on new division by default, but
1529 only in the __main__ module. You can usefully combine -Qwarn or
1530 -Qwarnall and -Qnew: this gives the __main__ module new division, and
1531 warns about classic division everywhere else.
1532 </obsolete>
Guido van Rossumae457142001-08-31 18:31:35 +00001533
Tim Petersbdee63f2001-09-02 03:40:59 +00001534- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +00001535 long, float, str, unicode, and tuple. (The types complex, list and
1536 dictionary can also be subclassed; this was introduced earlier.)
1537 Note that restrictions apply when subclassing immutable built-in
1538 types: you can only affect the value of the instance by overloading
1539 __new__. You can add mutable attributes, and the subclass instances
1540 will have a __dict__ attribute, but you cannot change the "value"
1541 (as implemented by the base class) of an immutable subclass instance
1542 once it is created.
1543
Guido van Rossumaaf80c82001-09-02 13:44:35 +00001544- The dictionary constructor now takes an optional argument, a
1545 mapping-like object, and initializes the dictionary from its
1546 (key, value) pairs.
1547
Tim Petersbdee63f2001-09-02 03:40:59 +00001548- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +00001549 "cooperative super calls" in a multiple inheritance setting. For an
1550 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
1551
Guido van Rossum8d7234d2001-09-06 22:02:58 +00001552- A new built-in type, property, has been added. This enables the
1553 creation of "properties". These are attributes implemented by
1554 getter and setter functions (or only one of these for read-only or
1555 write-only attributes), without the need to override __getattr__.
1556 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +00001557
Tim Petersbdee63f2001-09-02 03:40:59 +00001558- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +00001559 liberalized, to allow leading zeroes. Examples of literals now
1560 legal that were SyntaxErrors before:
1561
1562 00.0 0e3 0100j 07.5 00000000000000000008.
1563
Tim Petersbdee63f2001-09-02 03:40:59 +00001564- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +00001565 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
1566
Tim Petersedc99312001-08-22 21:36:50 +00001567Library
1568
Martin v. Löwiscb227c92001-09-06 08:54:16 +00001569- telnetlib includes symbolic names for the options, and support for
1570 setting an option negotiation callback.
1571
Tim Petersa40c7932001-09-05 22:36:56 +00001572- The new C standard no longer requires that math libraries set errno to
1573 ERANGE on overflow. For platform libraries that exploit this new
1574 freedom, Python's overflow-checking was wholly broken. A new overflow-
1575 checking scheme attempts to repair that, but may not be reliable on all
1576 platforms (C doesn't seem to provide anything both useful and portable
1577 in this area anymore).
1578
Martin v. Löwis44f86962001-09-05 13:44:54 +00001579- Asynchronous timeout actions are available through the new class
1580 threading.Timer.
1581
Tim Peters78526162001-09-05 00:53:45 +00001582- math.log and math.log10 now return sensible results for even huge
1583 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
1584
Tim Petersbdee63f2001-09-02 03:40:59 +00001585- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +00001586 currently held. See the docs for the imp module.
1587
Tim Petersbdee63f2001-09-02 03:40:59 +00001588- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +00001589 dumps containing ints written on platforms where Python ints are 8 bytes.
1590 When read on a box where Python ints are 4 bytes, such values are
1591 converted to Python longs.
1592
Tim Petersbdee63f2001-09-02 03:40:59 +00001593- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +00001594 code objects is no longer allowed. This plugs a security hole.
1595
Steve Purcell6091cd62001-09-06 16:05:17 +00001596- unittest.TestResult instances no longer store references to tracebacks
1597 generated by test failures. This prevents unexpected dangling references
1598 to objects that should be garbage collected between tests.
1599
Tim Petersedc99312001-08-22 21:36:50 +00001600Tools
1601
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001602- Tools/scripts/fixdiv.py has been added which can be used to fix
1603 division operators as per PEP 238.
1604
Tim Petersedc99312001-08-22 21:36:50 +00001605Build
1606
Barry Warsawd6c8ca62001-09-07 18:13:44 +00001607- If you are an adventurous person using Mac OS X you may want to look at
1608 Mac/OSX. There is a Makefile there that will build Python as a real Mac
1609 application, which can be used for experimenting with Carbon or Cocoa.
1610 Discussion of this on pythonmac-sig, please.
1611
Tim Peters7eea37e2001-09-04 22:08:56 +00001612C API
1613
1614- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +00001615
Tim Peters9fffa3e2001-09-04 05:14:19 +00001616- Note that PyLong_AsDouble can fail! This has always been true, but no
1617 callers checked for it. It's more likely to fail now, because overflow
1618 errors are properly detected now. The proper way to check:
1619
1620 double x = PyLong_AsDouble(some_long_object);
1621 if (x == -1.0 && PyErr_Occurred()) {
1622 /* The conversion failed. */
1623 }
1624
Tim Petersbdee63f2001-09-02 03:40:59 +00001625- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +00001626 compile but will not participate in GC. To upgrade an extension
1627 module:
1628
1629 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +00001630
Neil Schemenauer4042c692001-08-30 15:38:01 +00001631 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
1632 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +00001633
Neil Schemenauer4042c692001-08-30 15:38:01 +00001634 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
1635 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +00001636
Neil Schemenauer4042c692001-08-30 15:38:01 +00001637 - remove PyGC_HEAD_SIZE from object size calculations
1638
1639 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
1640
Tim Petersbdee63f2001-09-02 03:40:59 +00001641- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +00001642 These can be used safely to construct string objects from a
1643 sprintf-style format string (similar to the format string supported
1644 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +00001645
Tim Petersedc99312001-08-22 21:36:50 +00001646New platforms
1647
Tim Petersb7da0902001-09-02 23:01:43 +00001648- Stephen Hansen contributed patches sufficient to get a clean compile
1649 under Borland C (Windows), but he reports problems running it and ran
1650 out of time to complete the port. Volunteers? Expect a MemoryError
1651 when importing the types module; this is probably shallow, and
1652 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +00001653
Tim Petersedc99312001-08-22 21:36:50 +00001654Tests
1655
1656Windows
1657
Tim Peters6e13a562001-09-06 00:32:15 +00001658- Large file support is now enabled on Win32 platforms as well as on
1659 Win64. This means that, for example, you can use f.tell() and f.seek()
1660 to manipulate files larger than 2 gigabytes (provided you have enough
1661 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +00001662 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
1663 filesize limit, and large file support makes no difference there.
1664 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
1665 NTFS has no practical limit on file size, and files of any size can be
1666 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +00001667
Tim Petersbdee63f2001-09-02 03:40:59 +00001668- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +00001669 points to command.com (patch from Brian Quinlan).
1670
Tim Petersedc99312001-08-22 21:36:50 +00001671
Tim Peters20f51a72001-07-21 02:31:40 +00001672What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00001673Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +00001674===========================
1675
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001676Build
1677
Barry Warsaw18b2ecf2001-08-22 20:26:56 +00001678- Tim Peters developed a brand new Windows installer using Wise 8.1,
1679 generously donated to us by Wise Solutions.
1680
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001681- configure supports a new option --enable-unicode, with the values
1682 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
1683 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001684
Jack Jansen32ce0cd2001-08-21 19:28:20 +00001685- A new configure option --enable-framework builds a Mac OS X framework,
1686 which "make frameworkinstall" will install. This provides a starting
1687 point for more mac-like functionality, join pythonmac-sig@python.org
1688 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001689
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001690- The NeXT platform is no longer supported.
1691
1692- The `new' module is now statically linked.
1693
Tim Peters0afb6092001-08-15 06:06:44 +00001694Tools
1695
1696- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +00001697 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +00001698 the module docstring for details.
1699
Tim Peters20f51a72001-07-21 02:31:40 +00001700Tests
1701
Tim Peters5e824c32001-08-12 22:25:01 +00001702- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001703 platforms, allowing to give clearer test result output. regrtest
1704 also has optional --use/-u switch to run normally disabled tests
1705 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +00001706
Tim Peters20f51a72001-07-21 02:31:40 +00001707- Several new tests in the standard test suite, with special thanks to
1708 Nick Mathewson.
1709
1710Core
1711
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001712- The floor division operator // has been added as outlined in PEP
1713 238. The / operator still provides classic division (and will until
1714 Python 3.0) unless "from __future__ import division" is included, in
1715 which case the / operator will provide true division. The operator
1716 module provides truediv() and floordiv() functions. Augmented
1717 assignment variants are included, as are the equivalent overloadable
1718 methods and C API methods. See the PEP for a full discussion:
1719 <http://python.sf.net/peps/pep-0238.html>
1720
Tim Peters6cd6a822001-08-17 22:11:27 +00001721- Future statements are now effective in simulated interactive shells
1722 (like IDLE). This should "just work" by magic, but read Michael
1723 Hudson's "Future statements in simulated shells" PEP 264 for full
1724 details: <http://python.sf.net/peps/pep-0264.html>.
1725
Guido van Rossumf86ddd22001-08-17 21:21:04 +00001726- The type/class unification (PEP 252-253) was integrated into the
1727 trunk and is not so tentative any more (the exact specification of
1728 some features is still tentative). A lot of work has done on fixing
1729 bugs and adding robustness and features (performance still has to
1730 come a long way).
1731
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001732- Warnings about a mismatch in the Python API during extension import
1733 now use the Python warning framework (which makes it possible to
1734 write filters for these warnings).
1735
Barry Warsaw9b3be7f2001-08-14 18:35:02 +00001736- A function's __dict__ (aka func_dict) will now always be a
1737 dictionary. It used to be possible to delete it or set it to None,
1738 but now both actions raise TypeErrors. It is still legal to set it
1739 to a dictionary object. Getting func.__dict__ before any attributes
1740 have been assigned now returns an empty dictionary instead of None.
1741
Guido van Rossum32aa5d22001-09-05 18:43:35 +00001742- A new command line option, -E, was added which disables the use of
1743 all environment variables, or at least those that are specifically
1744 significant to Python. Usually those have a name starting with
1745 "PYTHON". This was used to fix a problem where the tests fail if
1746 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
1747 older distribution.
1748
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001749Library
1750
Tim Peters5e824c32001-08-12 22:25:01 +00001751- New class Differ and new functions ndiff() and restore() in difflib.py.
1752 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +00001753 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +00001754
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001755- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
1756 value using the minimal quoting required for the value; more
1757 reliable than using xml.sax.saxutils.escape() for attribute values.
1758
1759- Readline completion support for cmd.Cmd was added.
1760
Barry Warsaw6f3410d2001-08-22 04:08:41 +00001761- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
1762
1763- Added function threading.BoundedSemaphore()
1764
1765- Added Ka-Ping Yee's cgitb.py module.
1766
1767- The `new' module now exposes the CO_xxx flags.
1768
Martin v. Löwis560da622001-11-24 09:24:51 +00001769- The gc module offers the get_referents function.
1770
Marc-André Lemburgd6277912001-07-31 14:42:42 +00001771New platforms
1772
1773C API
1774
Marc-André Lemburg888fac02001-07-31 14:24:31 +00001775- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
1776 which provide a cross-platform implementations for the
1777 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
1778 the standard sprintf() and vsprintf() C lib APIs, these versions
1779 apply bounds checking on the used buffer which enhances protection
1780 against buffer overruns.
1781
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001782- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +00001783 and extensions using different Unicode widths is rendered next to
1784 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +00001785 will result in an ImportError. Unicode extensions writers must make
1786 sure to check the Unicode width compatibility in their extensions by
1787 using at least one of the mangled Unicode APIs in the extension.
1788
Martin v. Löwis339d0f72001-08-17 18:39:25 +00001789- Two new flags METH_NOARGS and METH_O are available in method definition
1790 tables to simplify implementation of methods with no arguments and a
1791 single untyped argument. Calling such methods is more efficient than
1792 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
1793 deprecated.
1794
Tim Petersc1731372001-08-04 08:12:36 +00001795Windows
1796
1797- "import module" now compiles module.pyw if it exists and nothing else
1798 relevant is found.
1799
Tim Peters20f51a72001-07-21 02:31:40 +00001800
Guido van Rossum55a78992001-07-17 17:22:32 +00001801What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +00001802Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +00001803===========================
1804
1805Core
Tim Petersa814db52001-05-14 07:05:58 +00001806
Tim Peters6d6c1a32001-08-02 04:15:00 +00001807- TENTATIVELY, a large amount of code implementing much of what's
1808 described in PEP 252 (Making Types Look More Like Classes) and PEP
1809 253 (Subtyping Built-in Types) was added. This will be released
1810 with Python 2.2a1. Documentation will be provided separately
1811 through http://www.python.org/2.2/. The purpose of releasing this
1812 with Python 2.2a1 is to test backwards compatibility. It is
1813 possible, though not likely, that a decision is made not to release
1814 this code as part of 2.2 final, if any serious backwards
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00001815 incompatibilities are found during alpha testing that cannot be
Tim Peters6d6c1a32001-08-02 04:15:00 +00001816 repaired.
1817
Guido van Rossum55a78992001-07-17 17:22:32 +00001818- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +00001819 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +00001820 more 'yield' statements. See PEP 255. Since this adds a new
1821 keyword to the language, this feature must be enabled by including a
1822 future statement: "from __future__ import generators" (see PEP 236).
1823 Generators will become a standard feature in a future release
1824 (probably 2.3). Without this future statement, 'yield' remains an
1825 ordinary identifier, but a warning is issued each time it is used.
1826 (These warnings currently don't conform to the warnings framework of
1827 PEP 230; we intend to fix this in 2.2a2.)
1828
Marc-André Lemburg12e74b32001-05-22 08:58:23 +00001829- The UTF-16 codec was modified to be more RFC compliant. It will now
1830 only remove BOM characters at the start of the string and then
1831 only if running in native mode (UTF-16-LE and -BE won't remove a
1832 leading BMO character).
1833
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001834- Strings now have a new method .decode() to complement the already
1835 existing .encode() method. These two methods provide direct access
1836 to the corresponding decoders and encoders of the registered codecs.
1837
1838 To enhance the usability of the .encode() method, the special
1839 casing of Unicode object return values was dropped (Unicode objects
1840 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +00001841
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001842 Both methods will now return whatever the codec in charge of the
1843 requested encoding returns as object, e.g. Unicode codecs will
1844 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
1845 will return u"äöü"). This enables codec writer to create codecs
1846 for various simple to use conversions.
1847
1848 New codecs were added to demonstrate these new features (the .encode()
1849 and .decode() columns indicate the type of the returned objects):
1850
1851 Name | .encode() | .decode() | Description
1852 ----------------------------------------------------------------------
1853 uu | string | string | UU codec (e.g. for email)
1854 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +00001855 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +00001856 zlib | string | string | zlib compression
1857 hex | string | string | 2-byte hex codec
1858 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
1859
Mark Hammond2a0af792001-05-14 03:09:36 +00001860- Some operating systems now support the concept of a default Unicode
1861 encoding for file system operations. Notably, Windows supports 'mbcs'
1862 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001863 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +00001864 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001865
1866 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +00001867 functions that return filenames (such as os.listdir()) to return Python
1868 string objects pre-encoded using the default file system encoding for
1869 the platform. As this encoding is likely to be different from Python's
1870 default encoding, converting this name to a Unicode object before passing
1871 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +00001872 would attempt to use its default encoding (generally ASCII) rather than
1873 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +00001874
Tim Petersa814db52001-05-14 07:05:58 +00001875 In general, this change simply removes surprises when working with
1876 Unicode and the file system, making these operations work as you expect,
1877 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +00001878 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +00001879
Tim Peters61dff2b2001-05-08 15:43:37 +00001880- Float (and complex) literals in source code were evaluated to full
1881 precision only when running from a .py file; the same code loaded from a
1882 .pyc (or .pyo) file could suffer numeric differences starting at about the
1883 12th significant decimal digit. For example, on a machine with IEEE-754
1884 floating arithmetic,
1885
1886 x = 9007199254740992.0
1887 print long(x)
1888
1889 printed 9007199254740992 if run directly from .py, but 9007199254740000
1890 if from a compiled (.pyc or .pyo) file. This was due to marshal using
1891 str(float) instead of repr(float) when building code objects. marshal
1892 now uses repr(float) instead, which should reproduce floats to full
1893 machine precision (assuming the platform C float<->string I/O conversion
1894 functions are of good quality).
1895
1896 This may cause floating-point results to change in some cases, and
1897 usually for the better, but may also cause numerically unstable
1898 algorithms to break.
1899
Tim Peters2f228e72001-05-13 00:19:31 +00001900- The implementation of dicts suffers fewer collisions, which has speed
1901 benefits. However, the order in which dict entries appear in dict.keys(),
1902 dict.values() and dict.items() may differ from previous releases for a
1903 given dict. Nothing is defined about this order, so no program should
1904 rely on it. Nevertheless, it's easy to write test cases that rely on the
1905 order by accident, typically because of printing the str() or repr() of a
1906 dict to an "expected results" file. See Lib/test/test_support.py's new
1907 sortdict(dict) function for a simple way to display a dict in sorted
1908 order.
1909
Tim Peters7a3bfc32001-06-12 01:22:22 +00001910- Many other small changes to dicts were made, resulting in faster
1911 operation along the most common code paths.
1912
Guido van Rossum10315822001-05-01 20:54:30 +00001913- Dictionary objects now support the "in" operator: "x in dict" means
1914 the same as dict.has_key(x).
1915
Barry Warsaw51acc8d2001-06-26 20:12:50 +00001916- The update() method of dictionaries now accepts generic mapping
1917 objects. Specifically the argument object must support the .keys()
1918 and __getitem__() methods. This allows you to say, for example,
1919 {}.update(UserDict())
1920
Guido van Rossum10315822001-05-01 20:54:30 +00001921- Iterators were added; this is a generalized way of providing values
1922 to a for loop. See PEP 234. There's a new built-in function iter()
1923 to return an iterator. There's a new protocol to get the next value
1924 from an iterator using the next() method (in Python) or the
1925 tp_iternext slot (in C). There's a new protocol to get iterators
1926 using the __iter__() method (in Python) or the tp_iter slot (in C).
1927 Iterating (i.e. a for loop) over a dictionary generates its keys.
1928 Iterating over a file generates its lines.
1929
Tim Petersf553f892001-05-01 20:45:31 +00001930- The following functions were generalized to work nicely with iterator
1931 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +00001932 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +00001933 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
1934 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +00001935 join() method of strings
1936 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +00001937 'x in y' and 'x not in y' (PySequence_Contains() in C API)
1938 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +00001939 right-hand side of assignment statements with multiple targets, such as
1940 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +00001941
Tim Petersd85e1022001-05-11 21:51:48 +00001942- Accessing module attributes is significantly faster (for example,
1943 random.random or os.path or yourPythonModule.yourAttribute).
1944
Tim Peterse63415e2001-05-08 04:38:29 +00001945- Comparing dictionary objects via == and != is faster, and now works even
1946 if the keys and values don't support comparisons other than ==.
1947
Tim Peters95bf9392001-05-10 08:32:44 +00001948- Comparing dictionaries in ways other than == and != is slower: there were
1949 insecurities in the dict comparison implementation that could cause Python
1950 to crash if the element comparison routines for the dict keys and/or
1951 values mutated the dicts. Making the code bulletproof slowed it down.
1952
Tim Peterseb28ef22001-06-02 05:27:19 +00001953- Collisions in dicts are resolved via a new approach, which can help
1954 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001955 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001956 faster now. Thanks to Christian Tismer for pointing out the cause and
1957 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001958
Tim Peters52e155e2001-06-16 05:42:57 +00001959- repr() is much faster for large containers (dict, list, tuple).
1960
1961
Tim Petersa814db52001-05-14 07:05:58 +00001962Library
1963
Fred Drake960fdf92001-07-20 18:38:26 +00001964- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00001965 were added to the string module. These a locale-independent
Fred Drake960fdf92001-07-20 18:38:26 +00001966 constants, unlike letters, lowercase, and uppercase. These are now
1967 use in appropriate locations in the standard library.
1968
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001969- The flags used in dlopen calls can now be configured using
1970 sys.setdlopenflags and queried using sys.getdlopenflags.
1971
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001972- Fredrik Lundh's xmlrpclib is now a standard library module. This
1973 provides full client-side XML-RPC support. In addition,
1974 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1975 one asyncore-based). Thanks to Eric Raymond for the documentation.
1976
Guido van Rossum643d3912001-07-05 14:46:25 +00001977- The xrange() object is simplified: it no longer supports slicing,
1978 repetition, comparisons, efficient 'in' checking, the tolist()
1979 method, or the start, stop and step attributes. See PEP 260.
1980
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001981- A new function fnmatch.filter to filter lists of file names was added.
1982
Barry Warsawffd674d2001-05-22 16:00:10 +00001983- calendar.py uses month and day names based on the current locale.
1984
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001985- strop is now *really* obsolete (this was announced before with 1.6),
1986 and issues DeprecationWarning when used (except for the four items
1987 that are still imported into string.py).
1988
Tim Petersa814db52001-05-14 07:05:58 +00001989- Cookie.py now sorts key+value pairs by key in output strings.
1990
1991- pprint.isrecursive(object) didn't correctly identify recursive objects.
1992 Now it does.
1993
Tim Peters95b3f782001-05-14 18:39:41 +00001994- pprint functions now much faster for large containers (tuple, list, dict).
1995
Tim Peters7b9542a2001-06-10 23:40:19 +00001996- New 'q' and 'Q' format codes in the struct module, corresponding to C
1997 types "long long" and "unsigned long long" (on Windows, __int64). In
1998 native mode, these can be used only when the platform C compiler supports
1999 these types (when HAVE_LONG_LONG is #define'd by the Python config
2000 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00002001 In standard mode, 'q' and 'Q' are supported on all platforms, and are
2002 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00002003
Guido van Rossum83213cc2001-06-12 16:48:52 +00002004- The site module installs a new built-in function 'help' that invokes
2005 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
2006 it displays a message reminding the user to use 'help()' or
2007 'help(object)'.
2008
Tim Petersa814db52001-05-14 07:05:58 +00002009Tests
2010
2011- New test_mutants.py runs dict comparisons where the key and value
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002012 comparison operators mutate the dicts randomly during comparison. This
Tim Petersa814db52001-05-14 07:05:58 +00002013 rapidly causes Python to crash under earlier releases (not for the faint
2014 of heart: it can also cause Win9x to freeze or reboot!).
2015
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002016- New test_pprint.py verifies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00002017 pprint.isreadable() return sensible results. Also verifies that simple
2018 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00002019
Tim Peters4324aa32001-05-28 22:30:08 +00002020C API
2021
2022- Removed the unused last_is_sticky argument from the internal
2023 _PyTuple_Resize(). If this affects you, you were cheating.
2024
2025
Guido van Rossum55a78992001-07-17 17:22:32 +00002026======================================================================
2027
2028
Guido van Rossumffe13be2001-04-16 18:46:45 +00002029What's New in Python 2.1 (final)?
2030=================================
2031
2032We only changed a few things since the last release candidate, all in
2033Python library code:
2034
2035- A bug in the locale module was fixed that affected locales which
2036 define no grouping for numeric formatting.
2037
2038- A few bugs in the weakref module's implementations of weak
2039 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
2040 and the test suite was updated to check for these bugs.
2041
2042- An old bug in the os.path.walk() function (introduced in Python
2043 2.0!) was fixed: a non-existent file would cause an exception
2044 instead of being ignored.
2045
2046- Fixed a few bugs in the new symtable module found by Neil Norwitz's
2047 PyChecker.
2048
2049
Guido van Rossum5b08f132001-04-16 02:05:23 +00002050What's New in Python 2.1c2?
2051===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00002052
Guido van Rossum5b08f132001-04-16 02:05:23 +00002053A flurry of small changes, and one showstopper fixed in the nick of
2054time made it necessary to release another release candidate. The list
2055here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00002056
Guido van Rossum5b08f132001-04-16 02:05:23 +00002057Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00002058
Guido van Rossum5b08f132001-04-16 02:05:23 +00002059- Tim discovered a nasty bug in the dictionary code, caused by
2060 PyDict_Next() calling dict_resize(), and the GC code's use of
2061 PyDict_Next() violating an assumption in dict_items(). This was
2062 fixed with considerable amounts of band-aid, but the net effect is a
2063 saner and more robust implementation.
2064
2065- Made a bunch of symbols static that were accidentally global.
2066
2067Build and Ports
2068
2069- The setup.py script didn't check for a new enough version of zlib
2070 (1.1.3 is needed). Now it does.
2071
2072- Changed "make clean" target to also remove shared libraries.
2073
2074- Added a more general warning about the SGI Irix optimizer to README.
2075
2076Library
2077
2078- Fix a bug in urllib.basejoin("http://host", "../file.html") which
2079 omitted the slash between host and file.html.
2080
2081- The mailbox module's _Mailbox class contained a completely broken
2082 and undocumented seek() method. Ripped it out.
2083
2084- Fixed a bunch of typos in various library modules (urllib2, smtpd,
2085 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
2086
2087- Fixed a few last-minute bugs in unittest.
2088
2089Extensions
2090
2091- Reverted the patch to the OpenSSL code in socketmodule.c to support
2092 RAND_status() and the EGD, and the subsequent patch that tried to
2093 fix it for pre-0.9.5 versions; the problem with the patch is that on
2094 some systems it issues a warning whenever socket is imported, and
2095 that's unacceptable.
2096
2097Tests
2098
2099- Fixed the pickle tests to work with "import test.test_pickle".
2100
2101- Tweaked test_locale.py to actually run the test Windows.
2102
2103- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
2104 not "wb" (which is not a valid mode at all).
2105
2106- Fix pstats browser crashes. Import readline if it exists to make
2107 the user interface nicer.
2108
2109- Add "import thread" to the top of test modules that import the
2110 threading module (test_asynchat and test_threadedtempfile). This
2111 prevents test failures caused by a broken threading module resulting
2112 from a previously caught failed import.
2113
2114- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
2115 needed on some platforms (e.g. Solaris 8) when the tests are run
2116 twice in succession.
2117
2118- Skip rather than fail test_sunaudiodev if no audio device is found.
2119
2120
2121What's New in Python 2.1c1?
2122===========================
2123
2124This list was significantly updated when 2.1c2 was released; the 2.1c1
2125release didn't mention most changes that were actually part of 2.1c1:
2126
2127Legal
2128
2129- Copyright was assigned to the Python Software Foundation (PSF) and a
2130 PSF license (very similar to the CNRI license) was added.
2131
2132- The CNRI copyright notice was updated to include 2001.
2133
2134Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00002135
Guido van Rossumc9932722001-04-12 02:31:27 +00002136- After a public outcry, assignment to __debug__ is no longer illegal;
2137 instead, a warning is issued. It will become illegal in 2.2.
2138
Guido van Rossum5b08f132001-04-16 02:05:23 +00002139- Fixed a core dump with "%#x" % 0, and changed the semantics so that
2140 "%#x" now always prepends "0x", even if the value is zero.
2141
2142- Fixed some nits in the bytecode compiler.
2143
2144- Fixed core dumps when calling certain kinds of non-functions.
2145
2146- Fixed various core dumps caused by reference count bugs.
2147
2148Build and Ports
2149
2150- Use INSTALL_SCRIPT to install script files.
2151
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002152- New port: SCO Unixware 7, by Billy G. Allie.
2153
Guido van Rossum5b08f132001-04-16 02:05:23 +00002154- Updated RISCOS port.
2155
2156- Updated BeOS port and notes.
2157
2158- Various other porting problems resolved.
2159
2160Library
2161
2162- The TERMIOS and SOCKET modules are now truly obsolete and
2163 unnecessary. Their symbols are incorporated in the termios and
2164 socket modules.
2165
2166- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
2167 better tests for pickling.
2168
2169- threading: make Condition.wait() robust against KeyboardInterrupt.
2170
2171- zipfile: add support to zipfile to support opening an archive
2172 represented by an open file rather than a file name. Fix bug where
2173 the archive was not properly closed. Fixed a bug in this bugfix
2174 where flush() was called for a read-only file.
2175
2176- imputil: added an uninstall() method to the ImportManager.
2177
2178- Canvas: fixed bugs in lower() and tkraise() methods.
2179
2180- SocketServer: API change (added overridable close_request() method)
2181 so that the TCP server can explicitly close the request.
2182
2183- pstats: Eric Raymond added a simple interactive statistics browser,
2184 invoked when the module is run as a script.
2185
2186- locale: fixed a problem in format().
2187
2188- webbrowser: made it work when the BROWSER environment variable has a
2189 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
2190 KDE 2. Fixed some other nits.
2191
2192- unittest: changes to allow using a different exception than
2193 AssertionError, and added a few more function aliases. Some other
2194 small changes.
2195
2196- urllib, urllib2: fixed redirect problems and a coupleof other nits.
2197
2198- asynchat: fixed a critical bug in asynchat that slipped through the
2199 2.1b2 release. Fixed another rare bug.
2200
2201- Fix some unqualified except: clauses (always a bad code example).
2202
2203XML
2204
2205- pyexpat: new API get_version_string().
2206
2207- Fixed some minidom bugs.
2208
2209Extensions
2210
2211- Fixed a core dump in _weakref. Removed the weakref.mapping()
2212 function (it adds nothing to the API).
2213
2214- Rationalized the use of header files in the readline module, to make
2215 it compile (albeit with some warnings) with the very recent readline
2216 4.2, without breaking for earlier versions.
2217
2218- Hopefully fixed a buffering problem in linuxaudiodev.
2219
2220- Attempted a fix to make the OpenSSL support in the socket module
2221 work again with pre-0.9.5 versions of OpenSSL.
2222
2223Tests
2224
2225- Added a test case for asynchat and asyncore.
2226
2227- Removed coupling between tests where one test failing could break
2228 another.
2229
2230Tools
2231
2232- Ping added an interactive help browser to pydoc, fixed some nits
2233 in the rest of the pydoc code, and added some features to his
2234 inspect module.
2235
2236- An updated python-mode.el version 4.1 which integrates Ken
2237 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
2238 much nicer in XEmacs and Emacs. When stepping through your program
2239 with pdb, in either the shell window or the *Python* window, the
2240 source file and line will be tracked by an arrow. Very cool!
2241
2242- IDLE: syntax warnings in interactive mode are changed into errors.
2243
2244- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00002245 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00002246
2247- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00002248
Barry Warsaw11e89c72001-04-11 20:37:57 +00002249
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002250What's New in Python 2.1 beta 2?
2251================================
2252
Guido van Rossum053ae352001-03-22 14:17:21 +00002253(Unlisted are many fixed bugs, more documentation, etc.)
2254
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002255Core language, builtins, and interpreter
2256
Guido van Rossum053ae352001-03-22 14:17:21 +00002257- The nested scopes work (enabled by "from __future__ import
2258 nested_scopes") is completed; in particular, the future now extends
2259 into code executed through exec, eval() and execfile(), and into the
2260 interactive interpreter.
2261
2262- When calling a base class method (e.g. BaseClass.__init__(self)),
2263 this is now allowed even if self is not strictly spoken a class
2264 instance (e.g. when using metaclasses or the Don Beaudry hook).
2265
2266- Slice objects are now comparable but not hashable; this prevents
2267 dict[:] from being accepted but meaningless.
2268
2269- Complex division is now calculated using less braindead algorithms.
2270 This doesn't change semantics except it's more likely to give useful
2271 results in extreme cases. Complex repr() now uses full precision
2272 like float repr().
2273
2274- sgmllib.py now calls handle_decl() for simple <!...> declarations.
2275
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002276- It is illegal to assign to the name __debug__, which is set when the
2277 interpreter starts. It is effectively a compile-time constant.
2278
2279- A warning will be issued if a global statement for a variable
2280 follows a use or assignment of that variable.
2281
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002282Standard library
2283
Guido van Rossum053ae352001-03-22 14:17:21 +00002284- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
2285 inspired by JUnit), is now part of the standard library. You now
2286 have a choice of two testing frameworks: unittest requires you to
2287 write testcases as separate code, doctest gathers them from
2288 docstrings. Both approaches have their advantages and
2289 disadvantages.
2290
2291- A new module Tix was added, which wraps the Tix extension library
2292 for Tk. With that module, it is not necessary to statically link
2293 Tix with _tkinter, since Tix will be loaded with Tcl's "package
2294 require" command. See Demo/tix/.
2295
2296- tzparse.py is now obsolete.
2297
2298- In gzip.py, the seek() and tell() methods are removed -- they were
2299 non-functional anyway, and it's better if callers can test for their
2300 existence with hasattr().
2301
2302Python/C API
2303
2304- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
2305 that's already in the dictionary during a PyDict_Next() iteration.
2306 This used to fail occasionally when a dictionary resize operation
2307 could be triggered that would rehash all the keys. All other
2308 modifications to the dictionary are still off-limits during a
2309 PyDict_Next() iteration!
2310
2311- New extended APIs related to passing compiler variables around.
2312
2313- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
2314 implement isinstance() and issubclass().
2315
2316- Py_BuildValue() now has a "D" conversion to create a Python complex
2317 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00002318
Fred Drake4e262a92001-03-22 18:26:47 +00002319- Extensions types which support weak references must now set the
2320 field allocated for the weak reference machinery to NULL themselves;
2321 this is done to avoid the cost of checking each object for having a
2322 weakly referencable type in PyObject_INIT(), since most types are
2323 not weakly referencable.
2324
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002325- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
2326 free variables and cell variables to and from the frame's f_locals.
2327
2328- Variants of several functions defined in pythonrun.h have been added
2329 to support the nested_scopes future statement. The variants all end
2330 in Flags and take an extra argument, a PyCompilerFlags *; examples:
2331 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
2332 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00002333 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00002334
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002335Distutils
2336
2337- the sdist command now writes a PKG-INFO file, as described in PEP 241,
2338 into the release tree.
2339
Tim Peters0e57abf2001-05-02 07:39:38 +00002340- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002341 (an uninstaller, more customization of the installer's display)
2342
2343- from Jack Jansen: added Mac-specific code to generate a dialog for
2344 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00002345 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002346 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00002347
2348- added 'platforms' and 'keywords' to the set of metadata that can be
2349 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00002350
2351- applied patches from Jason Tishler to make the compiler class work with
2352 Cygwin.
2353
2354
Tim Peters2fe289a2001-03-01 22:19:38 +00002355What's New in Python 2.1 beta 1?
2356================================
Tim Petersd66595f2001-02-04 03:09:53 +00002357
2358Core language, builtins, and interpreter
2359
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00002360- Following an outcry from the community about the amount of code
2361 broken by the nested scopes feature introduced in 2.1a2, we decided
2362 to make this feature optional, and to wait until Python 2.2 (or at
2363 least 6 months) to make it standard. The option can be enabled on a
2364 per-module basis by adding "from __future__ import nested_scopes" at
2365 the beginning of a module (before any other statements, but after
2366 comments and an optional docstring). See PEP 236 (Back to the
2367 __future__) for a description of the __future__ statement. PEP 227
2368 (Statically Nested Scopes) has been updated to reflect this change,
2369 and to clarify the semantics in a number of endcases.
2370
2371- The nested scopes code, when enabled, has been hardened, and most
2372 bugs and memory leaks in it have been fixed.
2373
2374- Compile-time warnings are now generated for a number of conditions
2375 that will break or change in meaning when nested scopes are enabled:
2376
2377 - Using "from...import *" or "exec" without in-clause in a function
2378 scope that also defines a lambda or nested function with one or
2379 more free (non-local) variables. The presence of the import* or
2380 bare exec makes it impossible for the compiler to determine the
2381 exact set of local variables in the outer scope, which makes it
2382 impossible to determine the bindings for free variables in the
2383 inner scope. To avoid the warning about import *, change it into
2384 an import of explicitly name object, or move the import* statement
2385 to the global scope; to avoid the warning about bare exec, use
2386 exec...in... (a good idea anyway -- there's a possibility that
2387 bare exec will be deprecated in the future).
2388
2389 - Use of a global variable in a nested scope with the same name as a
2390 local variable in a surrounding scope. This will change in
2391 meaning with nested scopes: the name in the inner scope will
2392 reference the variable in the outer scope rather than the global
2393 of the same name. To avoid the warning, either rename the outer
2394 variable, or use a global statement in the inner function.
2395
Neil Schemenauera35c6882001-02-27 04:45:05 +00002396- An optional object allocator has been included. This allocator is
2397 optimized for Python objects and should be faster and use less memory
2398 than the standard system allocator. It is not enabled by default
2399 because of possible thread safety problems. The allocator is only
2400 protected by the Python interpreter lock and it is possible that some
2401 extension modules require a thread safe allocator. The object
2402 allocator can be enabled by providing the "--with-pymalloc" option to
2403 configure.
2404
Tim Petersd66595f2001-02-04 03:09:53 +00002405Standard library
2406
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002407- pyexpat now detects the expat version if expat.h defines it. A
2408 number of additional handlers are provided, which are only available
2409 since expat 1.95. In addition, the methods SetParamEntityParsing and
2410 GetInputContext of Parser objects are available with 1.95.x
2411 only. Parser objects now provide the ordered_attributes and
2412 specified_attributes attributes. A new module expat.model was added,
2413 which offers a number of additional constants if 1.95.x is used.
2414
2415- xml.dom offers the new functions registerDOMImplementation and
2416 getDOMImplementation.
2417
2418- xml.dom.minidom offers a toprettyxml method. A number of DOM
2419 conformance issues have been resolved. In particular, Element now
2420 has an hasAttributes method, and the handling of namespaces was
2421 improved.
2422
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002423- Ka-Ping Yee contributed two new modules: inspect.py, a module for
2424 getting information about live Python code, and pydoc.py, a module
2425 for interactively converting docstrings to HTML or text.
2426 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00002427 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00002428 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
2429 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00002430
Tim Peters1eff7962001-03-01 02:31:33 +00002431- New library module difflib.py, primarily packaging the SequenceMatcher
2432 class at the heart of the popular ndiff.py file-comparison tool.
2433
2434- doctest.py (a framework for verifying Python code examples in docstrings)
2435 is now part of the std library.
2436
Tim Petersd66595f2001-02-04 03:09:53 +00002437Windows changes
2438
Guido van Rossume3955a82001-03-02 14:05:59 +00002439- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
2440 small GUI that lets you browse the module docstrings using your
2441 default web browser.
2442
Tim Peters1eff7962001-03-01 02:31:33 +00002443- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
2444 Platforms) is implemented. See
2445
2446 http://python.sourceforge.net/peps/pep-0235.html
2447
2448 for full details, especially the "Current Lower-Left Semantics" section.
2449 The new Windows import rules are simpler than before:
2450
2451 A. If the PYTHONCASEOK environment variable exists, same as
2452 before: silently accept the first case-insensitive match of any
2453 kind; raise ImportError if none found.
2454
2455 B. Else search sys.path for the first case-sensitive match; raise
2456 ImportError if none found.
2457
Raymond Hettingerf2f2a2c2002-08-19 14:25:03 +00002458 The same rules have been implemented on other platforms with case-
Tim Peters1eff7962001-03-01 02:31:33 +00002459 insensitive but case-preserving filesystems too (including Cygwin, and
2460 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00002461
Tim Peters25a9ce32001-02-19 07:06:36 +00002462- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
2463 what it's supposed to do (and does do under NT and 2000) via direct
2464 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00002465 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00002466 all Win9x systems before.
2467
Tim Peters1eff7962001-03-01 02:31:33 +00002468- Build: Subproject _test (effectively) renamed to _testcapi.
2469
Tim Peters2fe289a2001-03-01 22:19:38 +00002470New platforms
2471
2472- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
2473 Thanks to Steven Majewski!
2474
2475- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
2476 Tishler!
2477
Guido van Rossum9089b272001-03-02 06:49:50 +00002478- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
2479 Schwertberger! See RISCOS/README for more information -- it seems
2480 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00002481 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00002482
Tim Peters25a9ce32001-02-19 07:06:36 +00002483
Tim Petersd7b5e882001-01-25 03:36:26 +00002484What's New in Python 2.1 alpha 2?
2485=================================
Tim Peters40ead762001-01-27 05:35:26 +00002486
Tim Petersd7b5e882001-01-25 03:36:26 +00002487Core language, builtins, and interpreter
2488
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002489- Scopes nest. If a name is used in a function or class, but is not
2490 local, the definition in the nearest enclosing function scope will
2491 be used. One consequence of this change is that lambda statements
2492 could reference variables in the namespaces where the lambda is
2493 defined. In some unusual cases, this change will break code.
2494
2495 In all previous version of Python, names were resolved in exactly
2496 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002497 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00002498 function A is defined within a function B, the names bound in B are
2499 not visible in A. The new rules make names bound in B visible in A,
2500 unless A contains a name binding that hides the binding in B.
2501
2502 Section 4.1 of the reference manual describes the new scoping rules
2503 in detail. The test script in Lib/test/test_scope.py demonstrates
2504 some of the effects of the change.
2505
2506 The new rules will cause existing code to break if it defines nested
2507 functions where an outer function has local variables with the same
2508 name as globals or builtins used by the inner function. Example:
2509
2510 def munge(str):
2511 def helper(x):
2512 return str(x)
2513 if type(str) != type(''):
2514 str = helper(str)
2515 return str.strip()
2516
2517 Under the old rules, the name str in helper() is bound to the
2518 builtin function str(). Under the new rules, it will be bound to
2519 the argument named str and an error will occur when helper() is
2520 called.
2521
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002522- The compiler will report a SyntaxError if "from ... import *" occurs
2523 in a function or class scope. The language reference has documented
2524 that this case is illegal, but the compiler never checked for it.
2525 The recent introduction of nested scope makes the meaning of this
2526 form of name binding ambiguous. In a future release, the compiler
2527 may allow this form when there is no possibility of ambiguity.
2528
Tim Peters40ead762001-01-27 05:35:26 +00002529- repr(string) is easier to read, now using hex escapes instead of octal,
2530 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
2531
2532 >>> "\texample \r\n" + chr(0) + chr(255)
2533 '\texample \r\n\x00\xff' # in 2.1
2534 '\011example \015\012\000\377' # in 2.0
2535
Moshe Zadka6af0ce02001-01-29 06:41:00 +00002536- Functions are now compared and hashed by identity, not by value, since
2537 the func_code attribute is writable.
2538
Fred Drakefb9d7122001-02-01 20:00:40 +00002539- Weak references (PEP 205) have been added. This involves a few
2540 changes in the core, an extension module (_weakref), and a Python
2541 module (weakref). The weakref module is the public interface. It
2542 includes support for "explicit" weak references, proxy objects, and
2543 mappings with weakly held values.
2544
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002545- A 'continue' statement can now appear in a try block within the body
2546 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00002547 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00002548
Tim Petersd7b5e882001-01-25 03:36:26 +00002549Standard library
2550
Barry Warsaw30dbd142001-01-31 22:14:01 +00002551- mailbox.py now has a new class, PortableUnixMailbox which is
2552 identical to UnixMailbox but uses a more portable scheme for
2553 determining From_ separators. Also, the constructors for all the
2554 classes in this module have a new optional `factory' argument, which
2555 is a callable used when new message classes must be instantiated by
2556 the next() method.
2557
Tim Petersd7b5e882001-01-25 03:36:26 +00002558- random.py is now self-contained, and offers all the functionality of
2559 the now-deprecated whrandom.py. See the docs for details. random.py
2560 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00002561 and restoring the internal state of the generator; and jumpahead(n),
2562 for quickly forcing the internal state to be the same as if n calls to
2563 random() had been made. The latter is particularly useful for multi-
2564 threaded programs, creating one instance of the random.Random() class for
2565 each thread, then using .jumpahead() to force each instance to use a
2566 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00002567
Tim Peters0de88fc2001-02-01 04:59:18 +00002568- random.py's seed() function is new. For bit-for-bit compatibility with
2569 prior releases, use the whseed function instead. The new seed function
2570 addresses two problems: (1) The old function couldn't produce more than
2571 about 2**24 distinct internal states; the new one about 2**45 (the best
2572 that can be done in the Wichmann-Hill generator). (2) The old function
2573 sometimes produced identical internal states when passed distinct
2574 integers, and there was no simple way to predict when that would happen;
2575 the new one guarantees to produce distinct internal states for all
2576 arguments in [0, 27814431486576L).
2577
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00002578- The socket module now supports raw packets on Linux. The socket
2579 family is AF_PACKET.
2580
Tim Peters9ea17ac2001-02-02 05:57:15 +00002581- test_capi.py is a start at running tests of the Python C API. The tests
2582 are implemented by the new Modules/_testmodule.c.
2583
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00002584- A new extension module, _symtable, provides provisional access to the
2585 internal symbol table used by the Python compiler. A higher-level
2586 interface will be added on top of _symtable in a future release.
2587
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00002588- Removed the obsolete soundex module.
2589
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002590- xml.dom.minidom now uses the standard DOM exceptions. Node supports
2591 the isSameNode method; NamedNodeMap the get method.
2592
2593- xml.sax.expatreader supports the lexical handler property; it
2594 generates comment, startCDATA, and endCDATA events.
2595
Tim Petersee826f82001-01-31 19:39:44 +00002596Windows changes
2597
2598- Build procedure: the zlib project is built in a different way that
2599 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00002600 the zlib binary used. See PCbuild\readme.txt for details. Your old
2601 zlib-related directories can be deleted; you'll need to download fresh
2602 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00002603
Tim Peters9ea17ac2001-02-02 05:57:15 +00002604- Build: New subproject _test for the benefit of test_capi.py (see above).
2605
Tim Petersb16c56f2001-02-02 21:24:51 +00002606- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
2607 interface to some Python compiler internals).
2608
2609- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00002610 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00002611
Tim Petersa3a3a032000-11-30 05:22:44 +00002612What's New in Python 2.1 alpha 1?
2613=================================
2614
2615Core language, builtins, and interpreter
2616
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00002617- There is a new Unicode companion to the PyObject_Str() API
2618 called PyObject_Unicode(). It behaves in the same way as the
2619 former, but assures that the returned value is an Unicode object
2620 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00002621
Guido van Rossumf98eda02001-01-17 15:54:45 +00002622- The comparison operators support "rich comparison overloading" (PEP
2623 207). C extension types can provide a rich comparison function in
2624 the new tp_richcompare slot in the type object. The cmp() function
2625 and the C function PyObject_Compare() first try the new rich
2626 comparison operators before trying the old 3-way comparison. There
2627 is also a new C API PyObject_RichCompare() (which also falls back on
2628 the old 3-way comparison, but does not constrain the outcome of the
2629 rich comparison to a Boolean result).
2630
2631 The rich comparison function takes two objects (at least one of
2632 which is guaranteed to have the type that provided the function) and
2633 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
2634 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
2635 object, which may be NotImplemented (in which case the tp_compare
2636 slot function is used as a fallback, if defined).
2637
2638 Classes can overload individual comparison operators by defining one
2639 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00002640 __ge__. There are no explicit "reflected argument" versions of
2641 these; instead, __lt__ and __gt__ are each other's reflection,
2642 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
2643 reflection (similar at the C level). No other implications are
2644 made; in particular, Python does not assume that == is the Boolean
2645 inverse of !=, or that < is the Boolean inverse of >=. This makes
2646 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00002647
2648 Classes or types that want to implement (in)equality tests but not
2649 the ordering operators (i.e. unordered types) should implement ==
2650 and !=, and raise an error for the ordering operators.
2651
Guido van Rossuma88479f2001-01-18 14:28:08 +00002652 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00002653 Boolean; e.g. a matrix type might want to return a matrix of bits
2654 for A < B, giving elementwise comparisons. Such types should ensure
2655 that any interpretation of their value in a Boolean context raises
2656 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
2657 at the C level) to always raise an exception.
2658
Guido van Rossuma88479f2001-01-18 14:28:08 +00002659- Complex numbers use rich comparisons to define == and != but raise
2660 an exception for <, <=, > and >=. Unfortunately, this also means
2661 that cmp() of two complex numbers raises an exception when the two
2662 numbers differ. Since it is not mathematically meaningful to compare
2663 complex numbers except for equality, I hope that this doesn't break
2664 too much code.
2665
Tim Peters3389f192001-02-18 08:48:49 +00002666- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00002667 not defined by the language, other than that it's arbitrary but
2668 consistent (see the Reference Manual). An implementation detail changed
2669 in 2.1a1 such that None now compares less than any other object. Code
2670 relying on this new behavior (like code that relied on the previous
2671 behavior) does so at its own risk.
2672
Barry Warsaw573b5412001-01-15 20:43:18 +00002673- Functions and methods now support getting and setting arbitrarily
2674 named attributes (PEP 232). Functions have a new __dict__
2675 (a.k.a. func_dict) which hold the function attributes. Methods get
2676 and set attributes on their underlying im_func. It is a TypeError
2677 to set an attribute on a bound method.
2678
Guido van Rossum051e3352001-01-15 19:11:10 +00002679- The xrange() object implementation has been improved so that
2680 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
2681 limitation that in this case len(xrange(sys.maxint)) can't be
2682 calculated, but the common idiom "for i in xrange(sys.maxint)" will
2683 work fine as long as the index i doesn't actually reach 2**31.
2684 (Python uses regular ints for sequence and string indices; fixing
2685 that is much more work.)
2686
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002687- Two changes to from...import:
2688
Guido van Rossumba381232001-02-03 15:06:40 +00002689 1) "from M import X" now works even if (after loading module M)
2690 sys.modules['M'] is not a real module; it's basically a getattr()
2691 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00002692
2693 2) "from M import *" now looks for M.__all__ to decide which names to
2694 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
2695 filters out names starting with '_' as before. Whether or not
2696 __all__ exists, there's no restriction on the type of M.
2697
Guido van Rossumf61f1662001-01-10 20:13:55 +00002698- File objects have a new method, xreadlines(). This is the fastest
2699 way to iterate over all lines in a file:
2700
2701 for line in file.xreadlines():
2702 ...do something to line...
2703
2704 See the xreadlines module (mentioned below) for how to do this for
2705 other file-like objects.
2706
2707- Even if you don't use file.xreadlines(), you may expect a speedup on
2708 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00002709 quite a bit in platform-specific ways: on systems (like Linux) that
2710 support flockfile(), getc_unlocked(), and funlockfile(), those are
2711 used by default. On systems (like Windows) without getc_unlocked(),
2712 a complicated (but still thread-safe) method using fgets() is used by
2713 default.
2714
Tim Petersd52269b2001-01-25 06:23:18 +00002715 You can force use of the fgets() method by #define'ing
2716 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00002717 getc_unlocked()).
2718
Tim Petersd52269b2001-01-25 06:23:18 +00002719 You can force fgets() not to be used by #define'ing
2720 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00002721 test_bufio.py fails -- and let us know if it does!).
2722
2723- In addition, the fileinput module, while still slower than the other
2724 methods on most platforms, has been sped up too, by using
2725 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002726
2727- Support for run-time warnings has been added, including a new
2728 command line option (-W) to specify the disposition of warnings.
2729 See the description of the warnings module below.
2730
2731- Extensive changes have been made to the coercion code. This mostly
2732 affects extension modules (which can now implement mixed-type
2733 numerical operators without having to use coercion), but
2734 occasionally, in boundary cases the coercion semantics have changed
2735 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00002736 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00002737 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00002738 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00002739
Guido van Rossumf98eda02001-01-17 15:54:45 +00002740- In connection with the coercion changes, a new built-in singleton
2741 object, NotImplemented is defined. This can be returned for
2742 operations that wish to indicate they are not implemented for a
2743 particular combination of arguments. From C, this is
2744 Py_NotImplemented.
2745
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002746- The interpreter accepts now bytecode files on the command line even
2747 if they do not have a .pyc or .pyo extension. On Linux, after executing
2748
Martin v. Löwise214baa2001-02-04 22:37:56 +00002749import imp,sys,string
2750magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
2751reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
2752open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00002753
2754 any byte code file can be used as an executable (i.e. as an argument
2755 to execve(2)).
2756
Tim Peters9940b802000-12-01 07:59:35 +00002757- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00002758 character. In 1.6 and earlier, they never produced a sign,
2759 and raised an error if the value of the long was too large
2760 to fit in a Python int. In 2.0, they produced a sign if and
2761 only if too large to fit in an int. This was inconsistent
2762 across platforms (because the size of an int varies across
2763 platforms), and inconsistent with hex() and oct(). Example:
2764
2765 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00002766 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00002767 'ffffffbe' # in 2.0 and before, on 32-bit machines
2768 >>> hex(-0x42L)
2769 '-0x42L' # in all versions of Python
2770
Tim Peters9940b802000-12-01 07:59:35 +00002771 The behavior of %d formats for negative Python longs remains
2772 the same as in 2.0 (although in 1.6 and before, they raised
2773 an error if the long didn't fit in a Python int).
2774
2775 %u formats don't make sense for Python longs, but are allowed
2776 and treated the same as %d in 2.1. In 2.0, a negative long
2777 formatted via %u produced a sign if and only if too large to
2778 fit in an int. In 1.6 and earlier, a negative long formatted
2779 via %u raised an error if it was too big to fit in an int.
2780
Guido van Rossum3661d392000-12-12 22:10:31 +00002781- Dictionary objects have an odd new method, popitem(). This removes
2782 an arbitrary item from the dictionary and returns it (in the form of
2783 a (key, value) pair). This can be useful for algorithms that use a
2784 dictionary as a bag of "to do" items and repeatedly need to pick one
2785 item. Such algorithms normally end up running in quadratic time;
2786 using popitem() they can usually be made to run in linear time.
2787
Tim Peters36cdad12000-12-29 02:06:45 +00002788Standard library
2789
Thomas Woutersfe385252001-01-19 23:16:56 +00002790- In the time module, the time argument to the functions strftime,
2791 localtime, gmtime, asctime and ctime is now optional, defaulting to
2792 the current time (in the local timezone).
2793
Guido van Rossumda91f222001-01-15 16:36:08 +00002794- The ftplib module now defaults to passive mode, which is deemed a
2795 more useful default given that clients are often inside firewalls
2796 these days. Note that this could break if ftplib is used to connect
2797 to a *server* that is inside a firewall, from outside; this is
2798 expected to be a very rare situation. To fix that, you can call
2799 ftp.set_pasv(0).
2800
Martin v. Löwis10a27872001-01-13 09:54:41 +00002801- The module site now treats .pth files not only for path configuration,
2802 but also supports extensions to the initialization code: Lines starting
2803 with import are executed.
2804
Guido van Rossumf61f1662001-01-10 20:13:55 +00002805- There's a new module, warnings, which implements a mechanism for
2806 issuing and filtering warnings. There are some new built-in
2807 exceptions that serve as warning categories, and a new command line
2808 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
2809 turns warnings into errors). warnings.warn(message[, category])
2810 issues a warning message; this can also be called from C as
2811 PyErr_Warn(category, message).
2812
2813- A new module xreadlines was added. This exports a single factory
2814 function, xreadlines(). The intention is that this code is the
2815 absolutely fastest way to iterate over all lines in an open
2816 file(-like) object:
2817
2818 import xreadlines
2819 for line in xreadlines.xreadlines(file):
2820 ...do something to line...
2821
2822 This is equivalent to the previous the speed record holder using
2823 file.readlines(sizehint). Note that if file is a real file object
2824 (as opposed to a file-like object), this is equivalent:
2825
2826 for line in file.xreadlines():
2827 ...do something to line...
2828
Tim Peters36cdad12000-12-29 02:06:45 +00002829- The bisect module has new functions bisect_left, insort_left,
2830 bisect_right and insort_right. The old names bisect and insort
2831 are now aliases for bisect_right and insort_right. XXX_right
2832 and XXX_left methods differ in what happens when the new element
2833 compares equal to one or more elements already in the list: the
2834 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00002835 right. Code that doesn't care where equal elements end up should
2836 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00002837
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00002838- The new curses.panel module wraps the panel library that forms part
2839 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
2840
Guido van Rossumf61f1662001-01-10 20:13:55 +00002841- The SocketServer module now sets the allow_reuse_address flag by
2842 default in the TCPServer class.
2843
2844- A new function, sys._getframe(), returns the stack frame pointer of
2845 the caller. This is intended only as a building block for
2846 higher-level mechanisms such as string interpolation.
2847
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00002848- The pyexpat module supports a number of new handlers, which are
2849 available only in expat 1.2. If invocation of a callback fails, it
2850 will report an additional frame in the traceback. Parser objects
2851 participate now in garbage collection. If expat reports an unknown
2852 encoding, pyexpat will try to use a Python codec; that works only
2853 for single-byte charsets. The parser type objects is exposed as
2854 XMLParserObject.
2855
2856- xml.dom now offers standard definitions for symbolic node type and
2857 exception code constants, and a hierarchy of DOM exceptions. minidom
2858 was adjusted to use them.
2859
2860- The conformance of xml.dom.minidom to the DOM specification was
2861 improved. It detects a number of additional error cases; the
2862 previous/next relationship works even when the tree is modified;
2863 Node supports the normalize() method; NamedNodeMap, DocumentType and
2864 DOMImplementation classes were added; Element supports the
2865 hasAttribute and hasAttributeNS methods; and Text supports the splitText
2866 method.
2867
Guido van Rossumf61f1662001-01-10 20:13:55 +00002868Build issues
2869
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00002870- For Unix (and Unix-compatible) builds, configuration and building of
2871 extension modules is now greatly automated. Rather than having to
2872 edit the Modules/Setup file to indicate which modules should be
2873 built and where their include files and libraries are, a
2874 distutils-based setup.py script now takes care of building most
2875 extension modules. All extension modules built this way are built
2876 as shared libraries. Only a few modules that must be linked
2877 statically are still listed in the Setup file; you won't need to
2878 edit their configuration.
2879
2880- Python should now build out of the box on Cygwin. If it doesn't,
2881 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00002882
2883- Python now always uses its own (renamed) implementation of getopt()
2884 -- there's too much variation among C library getopt()
2885 implementations.
2886
2887- C++ compilers are better supported; the CXX macro is always set to a
2888 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00002889
Tim Petersd92dfe02000-12-12 01:18:41 +00002890Windows changes
2891
2892- select module: By default under Windows, a select() call
2893 can specify no more than 64 sockets. Python now boosts
2894 this Microsoft default to 512. If you need even more than
2895 that, see the MS docs (you'll need to #define FD_SETSIZE
2896 and recompile Python from source).
2897
Guido van Rossumf61f1662001-01-10 20:13:55 +00002898- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
2899 subdirectory is no more!
2900
Tim Petersa3a3a032000-11-30 05:22:44 +00002901
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002902What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00002903=========================
Guido van Rossum61000331997-08-15 04:39:58 +00002904
Guido van Rossum8ed602b2000-09-01 22:34:33 +00002905Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002906changes are in the file HISTORY. If you are making the jump directly
2907from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
2908HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00002909
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002910Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
2911the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
2912http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00002913
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002914--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00002915
2916======================================================================
2917
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002918What's new in 2.0 (since release candidate 1)?
2919==============================================
2920
2921Standard library
2922
2923- The copy_reg module was modified to clarify its intended use: to
2924 register pickle support for extension types, not for classes.
2925 pickle() will raise a TypeError if it is passed a class.
2926
2927- Fixed a bug in gettext's "normalize and expand" code that prevented
2928 it from finding an existing .mo file.
2929
2930- Restored support for HTTP/0.9 servers in httplib.
2931
Tim Peters989b7b92000-10-16 20:24:53 +00002932- The math module was changed to stop raising OverflowError in case of
2933 underflow, and return 0 instead in underflow cases. Whether Python
2934 used to raise OverflowError in case of underflow was platform-
2935 dependent (it did when the platform math library set errno to ERANGE
2936 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002937
2938- Fixed a bug in StringIO that occurred when the file position was not
2939 at the end of the file and write() was called with enough data to
2940 extend past the end of the file.
2941
2942- Fixed a bug that caused Tkinter error messages to get lost on
2943 Windows. The bug was fixed by replacing direct use of
2944 interp->result with Tcl_GetStringResult(interp).
2945
2946- Fixed bug in urllib2 that caused it to fail when it received an HTTP
2947 redirect response.
2948
2949- Several changes were made to distutils: Some debugging code was
2950 removed from util. Fixed the installer used when an external zip
2951 program (like WinZip) is not found; the source code for this
2952 installer is in Misc/distutils. check_lib() was modified to behave
2953 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2954 test for whether installed modules are on sys.path was changed to
2955 use both normcase() and normpath().
2956
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002957- Several minor bugs were fixed in the xml package (the minidom,
2958 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002959
2960- The regression test driver (regrtest.py) behavior when invoked with
2961 -l changed: It now reports a count of objects that are recognized as
2962 garbage but not freed by the garbage collector.
2963
Tim Peters989b7b92000-10-16 20:24:53 +00002964- The regression test for the math module was changed to test
2965 exceptional behavior when the test is run in verbose mode. Python
2966 cannot yet guarantee consistent exception behavior across platforms,
2967 so the exception part of test_math is run only in verbose mode, and
2968 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002969
2970Internals
2971
2972- PyOS_CheckStack() has been disabled on Win64, where it caused
2973 test_sre to fail.
2974
2975Build issues
2976
2977- Changed compiler flags, so that gcc is always invoked with -Wall and
2978 -Wstrict-prototypes. Users compiling Python with GCC should see
2979 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002980 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002981 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002982
Tim Petersa3a3a032000-11-30 05:22:44 +00002983- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002984
2985Tools and other miscellany
2986
2987- The compiler in Tools/compiler was updated to support the new
2988 language features introduced in 2.0: extended print statement, list
2989 comprehensions, and augmented assignments. The new compiler should
2990 also be backwards compatible with Python 1.5.2; the compiler will
2991 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002992 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002993
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002994What's new in 2.0 release candidate 1 (since beta 2)?
2995=====================================================
2996
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002997What is release candidate 1?
2998
2999We believe that release candidate 1 will fix all known bugs that we
3000intend to fix for the 2.0 final release. This release should be a bit
3001more stable than the previous betas. We would like to see even more
3002widespread testing before the final release, so we are producing this
3003release candidate. The final release will be exactly the same unless
3004any show-stopping (or brown bag) bugs are found by testers of the
3005release candidate.
3006
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003007All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003008to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003009
3010Core language, builtins, and interpreter
3011
3012- A bug that caused crashes when __coerce__ was used with augmented
3013 assignment, e.g. +=, was fixed.
3014
3015- Raise ZeroDivisionError when raising zero to a negative number,
3016 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
3017 power operator and the result of math.pow(0.0, -2.0) will vary by
3018 platform. On Linux, it raises a ValueError.
3019
3020- A bug in Unicode string interpolation was fixed that occasionally
3021 caused errors with formats including "%%". For example, the
3022 following expression "%% %s" % u"abc" no longer raises a TypeError.
3023
3024- Compilation of deeply nested expressions raises MemoryError instead
3025 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
3026
3027- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
3028 rendering them useless. They are now written in binary mode again.
3029
3030Standard library
3031
3032- Keyword arguments are now accepted for most pattern and match object
3033 methods in SRE, the standard regular expression engine.
3034
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003035- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00003036 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003037
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003038- Several bugs in the Unicode handling and error handling in _tkinter
3039 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003040
3041- Fix memory management errors in Merge() and Tkapp_Call() routines.
3042
3043- Several changes were made to cStringIO to make it compatible with
3044 the file-like object interface and with StringIO. If operations are
3045 performed on a closed object, an exception is raised. The truncate
3046 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00003047 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003048
3049- There were many changes made to the linuxaudiodev module and its
3050 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00003051 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003052
3053 Note that this module is named poorly, because it should work
3054 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00003055 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003056
3057 The module now raises exceptions when errors occur instead of
3058 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
3059 audio) and defines a getptr() method that calls the
3060 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
3061
3062- The library_version attribute, introduced in an earlier beta, was
3063 removed because it can not be supported with early versions of the C
3064 readline library, which provides no way to determine the version at
3065 compile-time.
3066
3067- The binascii module is now enabled on Win64.
3068
Tim Peters46446d62000-10-09 21:19:31 +00003069- tokenize.py no longer suffers "recursion depth" errors when parsing
3070 programs with very long string literals.
3071
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003072Internals
3073
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003074- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003075 which is called when the interpreter starts up to determine where
3076 the standard library is installed. These vulnerabilities affect all
3077 previous versions of Python and can be exploited by setting very
3078 long values for PYTHONHOME or argv[0]. The risk is greatest for a
3079 setuid Python script, although use of the wrapper in
3080 Misc/setuid-prog.c will eliminate the vulnerability.
3081
3082- Fixed garbage collection bugs in instance creation that were
3083 triggered when errors occurred during initialization. The solution,
3084 applied in cPickle and in PyInstance_New(), is to call
3085 PyObject_GC_Init() after the initialization of the object's
3086 container attributes is complete.
3087
3088- pyexpat adds definitions of PyModule_AddStringConstant and
3089 PyModule_AddObject if the Python version is less than 2.0, which
3090 provides compatibility with PyXML on Python 1.5.2.
3091
3092- If the platform has a bogus definition for LONG_BIT (the number of
3093 bits in a long), an error will be reported at compile time.
3094
3095- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
3096 collection crashes and possibly other, unreported crashes.
3097
3098- Fixed a memory leak in _PyUnicode_Fini().
3099
3100Build issues
3101
3102- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003103 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00003104 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003105
3106- The mmap.PAGESIZE constant is now initialized using sysconf when
3107 possible, which eliminates a dependency on -lucb for Reliant UNIX.
3108
3109- The md5 file should now compile on all platforms.
3110
3111- The select module now compiles on platforms that do not define
3112 POLLRDNORM and related constants.
3113
3114- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00003115 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003116
Jeremy Hylton10921202000-10-09 18:34:12 +00003117- BeOS: A number of changes were made to the build and installation
3118 process. ar-fake now operates on a directory of object files.
3119 dl_export.h is gone, and its macros now appear on the mwcc command
3120 line during build on PPC BeOS.
3121
Jeremy Hyltond6e20232000-10-16 20:08:38 +00003122- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00003123 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00003124
3125- Cygwin: Support for shared libraries, Tkinter, and sockets.
3126
3127- SunOS 4.1.4_JL: Fix test for directory existence in configure.
3128
3129Tools and other miscellany
3130
3131- Removed debugging prints from main used with freeze.
3132
Tim Peters46446d62000-10-09 21:19:31 +00003133- IDLE auto-indent no longer crashes when it encounters Unicode
3134 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003135
3136What's new in 2.0 beta 2 (since beta 1)?
3137========================================
3138
3139Core language, builtins, and interpreter
3140
Tim Peters482c0212000-09-26 06:33:09 +00003141- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003142 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003143
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003144- Add -h and -V command line options to print the usage message and
3145 Python version number and exit immediately.
3146
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003147- eval() and exec accept Unicode objects as code parameters.
3148
3149- getattr() and setattr() now also accept Unicode objects for the
3150 attribute name, which are converted to strings using the default
3151 encoding before lookup.
3152
3153- Multiplication on string and Unicode now does proper bounds
3154 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
3155 string is too long."
3156
3157- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00003158 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003159
Jeremy Hylton1b618592000-09-26 05:32:36 +00003160
3161Standard library and extensions
3162
Guido van Rossum5b08f132001-04-16 02:05:23 +00003163- socket module: the OpenSSL code now adds support for RAND_status()
3164 and EGD (Entropy Gathering Device).
3165
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003166- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00003167 argument checking; it still takes no arguments.
3168
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003169- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003170
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003171- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003172
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003173- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003174
3175- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003176 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003177
3178- copy: Copy Unicode objects atomically.
3179
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003180- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003181
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003182- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003183
Fred Drake67233bc2000-09-26 16:40:27 +00003184- dbm: Add get() and setdefault() methods to dbm object. Add constant
3185 `library' to module that names the library used. Added doc strings
3186 and method names to error messages. Uses configure to determine
3187 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
3188 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003189
3190- distutils: Update to version 0.9.3.
3191
3192- dl: Add several dl.RTLD_ constants.
3193
3194- fpectl: Now supported on FreeBSD.
3195
3196- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
3197 found by the collector will be saved in gc.garbage. This is useful
3198 for debugging a program that creates reference cycles.
3199
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003200- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00003201 of HTTP class. Do not close socket on zero-length response. Do not
3202 crash when server sends invalid content-length header.
3203
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003204- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003205
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003206- marshal: When reading a short, sign-extend on platforms where shorts
3207 are bigger than 16 bits. When reading a long, repair the unportable
3208 sign extension that was being done for 64-bit machines. (It assumed
3209 that signed right shift sign-extends.)
3210
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003211- operator: Add contains(), invert(), __invert__() as aliases for
3212 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003213
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003214- os: Add support for popen2() and popen3() on all platforms where
3215 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003216
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003217- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00003218 clicking on a file in Explorer (or passing the file name to the
3219 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003220
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003221- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00003222 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00003223
3224- pickle: Now raises ValueError when an invalid pickle that contains
3225 a non-string repr where a string repr was expected. This behavior
3226 matches cPickle.
3227
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003228- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003229
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003230- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003231
3232- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003233 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003234 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00003235
3236- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003237 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003238
3239- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00003240 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00003241 few cycles during startup since the first call to
3242 setdefaultencoding() will initialize the codec registry and the
3243 encodings package.
3244
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003245- socket: Support for size hint in readlines() method of object returned
3246 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003247
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003248- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00003249 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00003250 is followed by whitespace.
3251
Tim Petersa3a3a032000-11-30 05:22:44 +00003252- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003253
3254- struct: Check ranges for bytes and shorts.
3255
3256- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003257 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003258
3259- Tkinter: Image objects are now guaranteed to have unique ids. Set
3260 event.delta to zero if Tk version doesn't support mousewheel.
3261 Removed some debugging prints.
3262
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003263- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00003264
Fred Drake67233bc2000-09-26 16:40:27 +00003265- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003266 which works around a bug in Norton AntiVirus 2000 that leads directly
3267 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003268
3269- xml: New version detection code allows PyXML to override standard
3270 XML package if PyXML version is greater than 0.6.1.
3271
Fred Drake64bb3802000-09-26 16:21:35 +00003272- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
3273 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
3274 tree only for nodes which are sufficiently interesting to a specific
3275 application. Does not provide the HTML-specific extensions. Still
3276 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003277
Fred Drake64bb3802000-09-26 16:21:35 +00003278- xml.sax: SAX 2 support for Python, including all the handler
3279 interfaces needed to process XML 1.0 compliant XML. Some
3280 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003281
Fred Drake64bb3802000-09-26 16:21:35 +00003282- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
3283 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003284
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003285
Jeremy Hylton1b618592000-09-26 05:32:36 +00003286C API
3287
3288- Add three new convenience functions for module initialization --
3289 PyModule_AddObject(), PyModule_AddIntConstant(), and
3290 PyModule_AddStringConstant().
3291
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003292- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00003293 removed and add #error to Python.h if NULL isn't defined after
3294 #include of stdio.h.
3295
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003296- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00003297 backwards compatibility (at the source level) with old extensions.
3298
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003299- A wrapper API was added for signal() and sigaction(). Instead of
3300 either function, always use PyOS_getsig() to get a signal handler
3301 and PyOS_setsig() to set one. A new convenience typedef
3302 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003303
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003304- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00003305 internal data buffer and size of a string object -- or the default
3306 encoded version of a Unicode object.
3307
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003308- PyString_Size() and PyString_AsString() accept Unicode objects.
3309
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003310- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00003311 exists). INT_MAX and LONG_MAX will always be defined, even if
3312 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003313
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003314- PyFloat_FromString takes a second argument, pend, that was
3315 effectively useless. It is now officially useless but preserved for
3316 backwards compatibility. If the pend argument is not NULL, *pend is
3317 set to NULL.
3318
3319- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
3320 for the attribute name. See note on getattr() above.
3321
3322- A few bug fixes to argument processing for Unicode.
3323 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
3324 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
3325 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00003326 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003327
3328- Py_BuildValue accepts B format (for bgen-generated code).
3329
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003330
Jeremy Hylton1b618592000-09-26 05:32:36 +00003331Internals
3332
3333- On Unix, fix code for finding Python installation directory so that
3334 it works when argv[0] is a relative path.
3335
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00003336- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003337 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00003338 rather than by generating a copy of the object.
3339
Tim Peters482c0212000-09-26 06:33:09 +00003340- Several of the internal Unicode tables are much smaller now, and
3341 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003342
Jeremy Hylton97693b02000-09-26 17:42:51 +00003343- In the garbage collector: Fixed bug in collection of tuples. Fixed
3344 bug that caused some instances to be removed from the container set
3345 while they were still live. Fixed parsing in gc.set_debug() for
3346 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003347
3348- Fixed refcount problem in instance deallocation that only occurred
3349 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
3350
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003351- On Windows, getpythonregpath is now protected against null data in
3352 registry key.
3353
3354- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00003355 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003356
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003357
Jeremy Hylton1b618592000-09-26 05:32:36 +00003358Build and platform-specific issues
3359
3360- Better support of GNU Pth via --with-pth configure option.
3361
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003362- Python/C API now properly exposed to dynamically-loaded extension
3363 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00003364
3365- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
3366 Don't define MS_SYNC to be zero when it is undefined. Added missing
3367 prototypes in posixmodule.c.
3368
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003369- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003370 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00003371
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003372- Fix largefile support on older NetBSD systems and OpenBSD by adding
3373 define for TELL64.
3374
3375
3376Tools and other miscellany
3377
3378- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
3379
3380- freeze: The modulefinder now works with 2.0 opcodes.
3381
Tim Petersa3a3a032000-11-30 05:22:44 +00003382- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00003383 Move hackery of sys.argv until after the Tk instance has been
3384 created, which allows the application-specific Tkinter
3385 initialization to be executed if present; also pass an explicit
3386 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00003387
Jeremy Hylton1b618592000-09-26 05:32:36 +00003388
3389What's new in 2.0 beta 1?
3390=========================
3391
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003392Source Incompatibilities
3393------------------------
3394
3395None. Note that 1.6 introduced several incompatibilities with 1.5.2,
3396such as single-argument append(), connect() and bind(), and changes to
3397str(long) and repr(float).
3398
3399
3400Binary Incompatibilities
3401------------------------
3402
3403- Third party extensions built for Python 1.5.x or 1.6 cannot be used
3404with Python 2.0; these extensions will have to be rebuilt for Python
34052.0.
3406
3407- On Windows, attempting to import a third party extension built for
3408Python 1.5.x or 1.6 results in an immediate crash; there's not much we
3409can do about this. Check your PYTHONPATH environment variable!
3410
3411- Python bytecode files (*.pyc and *.pyo) are not compatible between
3412releases.
3413
3414
3415Overview of Changes Since 1.6
3416-----------------------------
3417
3418There are many new modules (including brand new XML support through
3419the xml package, and i18n support through the gettext module); a list
3420of all new modules is included below. Lots of bugs have been fixed.
3421
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003422The process for making major new changes to the language has changed
3423since Python 1.6. Enhancements must now be documented by a Python
3424Enhancement Proposal (PEP) before they can be accepted.
3425
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003426There are several important syntax enhancements, described in more
3427detail below:
3428
3429 - Augmented assignment, e.g. x += 1
3430
3431 - List comprehensions, e.g. [x**2 for x in range(10)]
3432
3433 - Extended import statement, e.g. import Module as Name
3434
3435 - Extended print statement, e.g. print >> file, "Hello"
3436
3437Other important changes:
3438
3439 - Optional collection of cyclical garbage
3440
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003441Python Enhancement Proposal (PEP)
3442---------------------------------
3443
3444PEP stands for Python Enhancement Proposal. A PEP is a design
3445document providing information to the Python community, or describing
3446a new feature for Python. The PEP should provide a concise technical
3447specification of the feature and a rationale for the feature.
3448
3449We intend PEPs to be the primary mechanisms for proposing new
3450features, for collecting community input on an issue, and for
3451documenting the design decisions that have gone into Python. The PEP
3452author is responsible for building consensus within the community and
3453documenting dissenting opinions.
3454
3455The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003456
3457Augmented Assignment
3458--------------------
3459
3460This must have been the most-requested feature of the past years!
3461Eleven new assignment operators were added:
3462
Guido van Rossume905e952000-09-05 12:42:46 +00003463 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003464
3465For example,
3466
3467 A += B
3468
3469is similar to
3470
3471 A = A + B
3472
3473except that A is evaluated only once (relevant when A is something
3474like dict[index].attr).
3475
3476However, if A is a mutable object, A may be modified in place. Thus,
3477if A is a number or a string, A += B has the same effect as A = A+B
3478(except A is only evaluated once); but if a is a list, A += B has the
3479same effect as A.extend(B)!
3480
3481Classes and built-in object types can override the new operators in
3482order to implement the in-place behavior; the not-in-place behavior is
3483used automatically as a fallback when an object doesn't implement the
3484in-place behavior. For classes, the method name is derived from the
3485method name for the corresponding not-in-place operator by inserting
3486an 'i' in front of the name, e.g. __iadd__ implements in-place
3487__add__.
3488
3489Augmented assignment was implemented by Thomas Wouters.
3490
3491
3492List Comprehensions
3493-------------------
3494
3495This is a flexible new notation for lists whose elements are computed
3496from another list (or lists). The simplest form is:
3497
3498 [<expression> for <variable> in <sequence>]
3499
Guido van Rossum56db0952000-09-06 23:34:25 +00003500For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003501This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003502
3503You can also add a condition:
3504
3505 [<expression> for <variable> in <sequence> if <condition>]
3506
3507For example, [w for w in words if w == w.lower()] would yield the list
3508of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003509than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003510
3511You can also have nested for loops and more than one 'if' clause. For
3512example, here's a function that flattens a sequence of sequences::
3513
3514 def flatten(seq):
3515 return [x for subseq in seq for x in subseq]
3516
3517 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
3518
3519This prints
3520
3521 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
3522
3523List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003524Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003525
3526
3527Extended Import Statement
3528-------------------------
3529
3530Many people have asked for a way to import a module under a different
3531name. This can be accomplished like this:
3532
3533 import foo
3534 bar = foo
3535 del foo
3536
3537but this common idiom gets old quickly. A simple extension of the
3538import statement now allows this to be written as follows:
3539
3540 import foo as bar
3541
3542There's also a variant for 'from ... import':
3543
3544 from foo import bar as spam
3545
3546This also works with packages; e.g. you can write this:
3547
3548 import test.regrtest as regrtest
3549
3550Note that 'as' is not a new keyword -- it is recognized only in this
3551context (this is only possible because the syntax for the import
3552statement doesn't involve expressions).
3553
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003554Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003555
3556
3557Extended Print Statement
3558------------------------
3559
3560Easily the most controversial new feature, this extension to the print
3561statement adds an option to make the output go to a different file
3562than the default sys.stdout.
3563
3564For example, to write an error message to sys.stderr, you can now
3565write:
3566
3567 print >> sys.stderr, "Error: bad dog!"
3568
3569As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00003570evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003571
3572 print >> None, "Hello world"
3573
3574is equivalent to
3575
3576 print "Hello world"
3577
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003578Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003579
3580
3581Optional Collection of Cyclical Garbage
3582---------------------------------------
3583
3584Python is now equipped with a garbage collector that can hunt down
3585cyclical references between Python objects. It's no replacement for
3586reference counting; in fact, it depends on the reference counts being
3587correct, and decides that a set of objects belong to a cycle if all
3588their reference counts can be accounted for from their references to
3589each other. This devious scheme was first proposed by Eric Tiedemann,
3590and brought to implementation by Neil Schemenauer.
3591
3592There's a module "gc" that lets you control some parameters of the
3593garbage collection. There's also an option to the configure script
3594that lets you enable or disable the garbage collection. In 2.0b1,
3595it's on by default, so that we (hopefully) can collect decent user
3596experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00003597performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003598off by default in the final 2.0 release.
3599
3600
3601Smaller Changes
3602---------------
3603
3604A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
3605map(None, seq1, seq2, ...) when the sequences have the same length;
3606i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
3607the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003608zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003609
3610sys.version_info is a tuple (major, minor, micro, level, serial).
3611
3612Dictionaries have an odd new method, setdefault(key, default).
3613dict.setdefault(key, default) returns dict[key] if it exists; if not,
3614it sets dict[key] to default and returns that value. Thus:
3615
3616 dict.setdefault(key, []).append(item)
3617
3618does the same work as this common idiom:
3619
3620 if not dict.has_key(key):
3621 dict[key] = []
3622 dict[key].append(item)
3623
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003624There are two new variants of SyntaxError that are raised for
3625indentation-related errors: IndentationError and TabError.
3626
3627Changed \x to consume exactly two hex digits; see PEP 223. Added \U
3628escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003629
3630The limits on the size of expressions and file in Python source code
3631have been raised from 2**16 to 2**32. Previous versions of Python
3632were limited because the maximum argument size the Python VM accepted
3633was 2**16. This limited the size of object constructor expressions,
3634e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
3635limit was raised thanks to a patch by Charles Waldman that effectively
3636fixes the problem. It is now much more likely that you will be
3637limited by available memory than by an arbitrary limit in Python.
3638
3639The interpreter's maximum recursion depth can be modified by Python
3640programs using sys.getrecursionlimit and sys.setrecursionlimit. This
3641limit is the maximum number of recursive calls that can be made by
3642Python code. The limit exists to prevent infinite recursion from
3643overflowing the C stack and causing a core dump. The default value is
36441000. The maximum safe value for a particular platform can be found
3645by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003646
3647New Modules and Packages
3648------------------------
3649
3650atexit - for registering functions to be called when Python exits.
3651
3652imputil - Greg Stein's alternative API for writing custom import
3653hooks.
3654
3655pyexpat - an interface to the Expat XML parser, contributed by Paul
3656Prescod.
3657
3658xml - a new package with XML support code organized (so far) in three
3659subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
3660would fill a volume. There's a special feature whereby a
3661user-installed package named _xmlplus overrides the standard
3662xmlpackage; this is intended to give the XML SIG a hook to distribute
3663backwards-compatible updates to the standard xml package.
3664
3665webbrowser - a platform-independent API to launch a web browser.
3666
3667
Guido van Rossume905e952000-09-05 12:42:46 +00003668Changed Modules
3669---------------
3670
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003671array -- new methods for array objects: count, extend, index, pop, and
3672remove
3673
3674binascii -- new functions b2a_hex and a2b_hex that convert between
3675binary data and its hex representation
3676
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003677calendar -- Many new functions that support features including control
3678over which day of the week is the first day, returning strings instead
3679of printing them. Also new symbolic constants for days of week,
3680e.g. MONDAY, ..., SUNDAY.
3681
3682cgi -- FieldStorage objects have a getvalue method that works like a
3683dictionary's get method and returns the value attribute of the object.
3684
3685ConfigParser -- The parser object has new methods has_option,
3686remove_section, remove_option, set, and write. They allow the module
3687to be used for writing config files as well as reading them.
3688
3689ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00003690optionally support the RFC 959 REST command.
3691
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003692gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00003693
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003694httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
3695the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00003696
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003697locale -- implement getdefaultlocale for Win32 and Macintosh
3698
3699marshal -- no longer dumps core when marshaling deeply nested or
3700recursive data structures
3701
3702os -- new functions isatty, seteuid, setegid, setreuid, setregid
3703
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003704os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
3705support under Unix.
3706
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003707os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003708
3709os.path -- fix semantics of os.path.commonprefix
3710
3711smtplib -- support for sending very long messages
3712
3713socket -- new function getfqdn()
3714
3715readline -- new functions to read, write and truncate history files.
3716The readline section of the library reference manual contains an
3717example.
3718
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003719select -- add interface to poll system call
3720
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003721shutil -- new copyfileobj function
3722
3723SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
3724HTTP server.
3725
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003726Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003727
3728urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00003729e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003730
3731whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00003732
3733
3734Obsolete Modules
3735----------------
3736
3737None. However note that 1.6 made a whole slew of modules obsolete:
3738stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
3739poly, zmod, strop, util, whatsound.
3740
3741
3742Changed, New, Obsolete Tools
3743----------------------------
3744
Tim Peters8b092332000-09-05 20:15:25 +00003745None.
Guido van Rossume905e952000-09-05 12:42:46 +00003746
3747
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003748C-level Changes
3749---------------
3750
3751Several cleanup jobs were carried out throughout the source code.
3752
3753All C code was converted to ANSI C; we got rid of all uses of the
3754Py_PROTO() macro, which makes the header files a lot more readable.
3755
3756Most of the portability hacks were moved to a new header file,
3757pyport.h; several other new header files were added and some old
3758header files were removed, in an attempt to create a more rational set
3759of header files. (Few of these ever need to be included explicitly;
3760they are all included by Python.h.)
3761
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003762Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003763and Win64, especially for the new Intel Itanium processor. Mick also
3764added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00003765
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003766The C APIs to return an object's size have been update to consistently
3767use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
3768previous versions, the abstract interfaces used PyXXX_Length and the
3769concrete interfaces used PyXXX_Size. The old names,
3770e.g. PyObject_Length, are still available for backwards compatibility
3771at the API level, but are deprecated.
3772
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003773The PyOS_CheckStack function has been implemented on Windows by
3774Fredrik Lundh. It prevents Python from failing with a stack overflow
3775on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003776
3777The GC changes resulted in creation of two new slots on object,
3778tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00003779the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003780
3781The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00003782C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003783
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003784PyErr_Format has been updated to automatically calculate the size of
3785the buffer needed to hold the formatted result string. This change
3786prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00003787
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003788New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00003789
Jeremy Hylton24c3d602000-09-05 19:36:26 +00003790PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
3791that are the same as their non-Ex counterparts except they take an
3792extra flag argument that tells them to close the file when done.
3793
3794XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003795
Tim Peters8b092332000-09-05 20:15:25 +00003796
3797Windows Changes
3798---------------
3799
3800New popen2/popen3/peopen4 in os module (see Changed Modules above).
3801
3802os.popen is much more usable on Windows 95 and 98. See Microsoft
3803Knowledge Base article Q150956. The Win9x workaround described there
3804is implemented by the new w9xpopen.exe helper in the root of your
3805Python installation. Note that Python uses this internally; it is not
3806a standalone program.
3807
3808Administrator privileges are no longer required to install Python
3809on Windows NT or Windows 2000. If you have administrator privileges,
3810Python's registry info will be written under HKEY_LOCAL_MACHINE.
3811Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00003812under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00003813uses of Python, but will prevent some advanced uses from working
3814(for example, running a Python script as an NT service, or possibly
3815from CGI).
3816
3817[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
3818installer; instead, it installs the needed Tcl/Tk files directly in the
3819Python directory. If you already have a Tcl/Tk installation, this
3820wastes some disk space (about 4 Megs) but avoids problems with
3821conflicting Tcl/Tk installations, and makes it much easier for Python
3822to ensure that Tcl/Tk can find all its files.
3823
3824[This was new in 1.6] The Windows installer now installs by default in
3825\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
3826
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00003827
3828Updates to the changes between 1.5.2 and 1.6
3829--------------------------------------------
3830
3831The 1.6 NEWS file can't be changed after the release is done, so here
3832is some late-breaking news:
3833
3834New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
3835and changes to getlocale() and setlocale().
3836
3837The new module is now enabled per default.
3838
3839It is not true that the encodings codecs cannot be used for normal
3840strings: the string.encode() (which is also present on 8-bit strings
3841!) allows using them for 8-bit strings too, e.g. to convert files from
3842cp1252 (Windows) to latin-1 or vice-versa.
3843
3844Japanese codecs are available from Tamito KAJIYAMA:
3845http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
3846
3847
Guido van Rossumab9d6f01998-08-10 22:01:13 +00003848======================================================================