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Tim Petersedc99312001-08-22 21:36:50 +00001What's New in Python 2.2a3?
2===========================
3
4Core
5
Tim Peters9fffa3e2001-09-04 05:14:19 +00006- Conversion of long to float now raises OverflowError if the long is too
7 big to represent as a C double.
8
Tim Peters32f453e2001-09-03 08:35:41 +00009- The 3-argument builtin pow() no longer allows a third non-None argument
10 if either of the first two arguments is a float, or if both are of
11 integer types and the second argument is negative (in which latter case
12 the arguments are converted to float, so this is really the same
13 restriction).
14
Tim Peters5d2b77c2001-09-03 05:47:38 +000015- The builtin dir() now returns more information, and sometimes much
16 more, generally naming all attributes of an object, and all attributes
17 reachable from the object via its class, and from its class's base
18 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
19 an empty list. In 2.2a3,
20
21 >>> dir([])
22 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
23 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
24 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
25 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
26 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
27 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
28 'reverse', 'sort']
29
30 dir(module) continues to return only the module's attributes, though.
31
Tim Petersbdee63f2001-09-02 03:40:59 +000032- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +000033 than raising OverflowError. This is a partial implementation of PEP
34 237. You can use -Wdefault::OverflowWarning to enable a warning for
35 this situation, and -Werror::OverflowWarning to revert to the old
36 OverflowError exception.
37
Guido van Rossum61c345f2001-09-04 03:26:15 +000038- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +000039 warnings for the use of classic division. (See PEP 238.) Possible
Guido van Rossum61c345f2001-09-04 03:26:15 +000040 values are -Qold, -Qwarn, and -Qnew. The default is -Qold, meaning
Guido van Rossumae457142001-08-31 18:31:35 +000041 the / operator has its classic meaning and no warnings are issued.
Guido van Rossum61c345f2001-09-04 03:26:15 +000042 Using -Qwarn issues a run-time warning about all uses of classic
43 division for int, long, float and complex arguments. Using -Qnew is
Guido van Rossumae457142001-08-31 18:31:35 +000044 questionable; it turns on new division by default, but only in the
Guido van Rossum61c345f2001-09-04 03:26:15 +000045 __main__ module. You can usefully combine -Qwarn and -Qnew: this
Guido van Rossumae457142001-08-31 18:31:35 +000046 gives the __main__ module new division, and warns about classic
47 division everywhere else.
48
Tim Petersbdee63f2001-09-02 03:40:59 +000049- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +000050 long, float, str, unicode, and tuple. (The types complex, list and
51 dictionary can also be subclassed; this was introduced earlier.)
52 Note that restrictions apply when subclassing immutable built-in
53 types: you can only affect the value of the instance by overloading
54 __new__. You can add mutable attributes, and the subclass instances
55 will have a __dict__ attribute, but you cannot change the "value"
56 (as implemented by the base class) of an immutable subclass instance
57 once it is created.
58
Guido van Rossumaaf80c82001-09-02 13:44:35 +000059- The dictionary constructor now takes an optional argument, a
60 mapping-like object, and initializes the dictionary from its
61 (key, value) pairs.
62
Tim Petersbdee63f2001-09-02 03:40:59 +000063- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +000064 "cooperative super calls" in a multiple inheritance setting. For an
65 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
66
Tim Petersbdee63f2001-09-02 03:40:59 +000067- A new built-in type, getset, has been added. This enables the
Guido van Rossumae457142001-08-31 18:31:35 +000068 creation of "computed attributes". Such attributes are implemented
69 by getter and setter functions (or only one of these for read-only
70 or write-only attributes), without the need to override
71 __getattr__. See http://www.python.org/2.2/descrintro.html#getset
72
Tim Petersbdee63f2001-09-02 03:40:59 +000073- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +000074 liberalized, to allow leading zeroes. Examples of literals now
75 legal that were SyntaxErrors before:
76
77 00.0 0e3 0100j 07.5 00000000000000000008.
78
Tim Petersbdee63f2001-09-02 03:40:59 +000079- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +000080 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
81
Tim Petersedc99312001-08-22 21:36:50 +000082Library
83
Tim Petersbdee63f2001-09-02 03:40:59 +000084- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +000085 currently held. See the docs for the imp module.
86
Tim Petersbdee63f2001-09-02 03:40:59 +000087- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +000088 dumps containing ints written on platforms where Python ints are 8 bytes.
89 When read on a box where Python ints are 4 bytes, such values are
90 converted to Python longs.
91
Tim Petersbdee63f2001-09-02 03:40:59 +000092- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +000093 code objects is no longer allowed. This plugs a security hole.
94
Tim Petersedc99312001-08-22 21:36:50 +000095Tools
96
97Build
98
Tim Peters69232342001-08-30 05:16:13 +000099API
100
Tim Peters9fffa3e2001-09-04 05:14:19 +0000101- Note that PyLong_AsDouble can fail! This has always been true, but no
102 callers checked for it. It's more likely to fail now, because overflow
103 errors are properly detected now. The proper way to check:
104
105 double x = PyLong_AsDouble(some_long_object);
106 if (x == -1.0 && PyErr_Occurred()) {
107 /* The conversion failed. */
108 }
109
Tim Petersbdee63f2001-09-02 03:40:59 +0000110- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000111 compile but will not participate in GC. To upgrade an extension
112 module:
113
114 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000115
Neil Schemenauer4042c692001-08-30 15:38:01 +0000116 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
117 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000118
Neil Schemenauer4042c692001-08-30 15:38:01 +0000119 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
120 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000121
Neil Schemenauer4042c692001-08-30 15:38:01 +0000122 - remove PyGC_HEAD_SIZE from object size calculations
123
124 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
125
Tim Petersbdee63f2001-09-02 03:40:59 +0000126- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000127 These can be used safely to construct string objects from a
128 sprintf-style format string (similar to the format string supported
129 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000130
Tim Petersedc99312001-08-22 21:36:50 +0000131New platforms
132
Tim Petersb7da0902001-09-02 23:01:43 +0000133- Stephen Hansen contributed patches sufficient to get a clean compile
134 under Borland C (Windows), but he reports problems running it and ran
135 out of time to complete the port. Volunteers? Expect a MemoryError
136 when importing the types module; this is probably shallow, and
137 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000138
Tim Petersedc99312001-08-22 21:36:50 +0000139Tests
140
141Windows
142
Tim Petersbdee63f2001-09-02 03:40:59 +0000143- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000144 points to command.com (patch from Brian Quinlan).
145
Tim Petersedc99312001-08-22 21:36:50 +0000146
Tim Peters20f51a72001-07-21 02:31:40 +0000147What's New in Python 2.2a2?
148===========================
149
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000150Build
151
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000152- Tim Peters developed a brand new Windows installer using Wise 8.1,
153 generously donated to us by Wise Solutions.
154
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000155- configure supports a new option --enable-unicode, with the values
156 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
157 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000158
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000159- A new configure option --enable-framework builds a Mac OS X framework,
160 which "make frameworkinstall" will install. This provides a starting
161 point for more mac-like functionality, join pythonmac-sig@python.org
162 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000163
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000164- The NeXT platform is no longer supported.
165
166- The `new' module is now statically linked.
167
Tim Peters0afb6092001-08-15 06:06:44 +0000168Tools
169
170- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000171 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000172 the module docstring for details.
173
Tim Peters20f51a72001-07-21 02:31:40 +0000174Tests
175
Tim Peters5e824c32001-08-12 22:25:01 +0000176- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000177 platforms, allowing to give clearer test result output. regrtest
178 also has optional --use/-u switch to run normally disabled tests
179 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000180
Tim Peters20f51a72001-07-21 02:31:40 +0000181- Several new tests in the standard test suite, with special thanks to
182 Nick Mathewson.
183
184Core
185
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000186- The floor division operator // has been added as outlined in PEP
187 238. The / operator still provides classic division (and will until
188 Python 3.0) unless "from __future__ import division" is included, in
189 which case the / operator will provide true division. The operator
190 module provides truediv() and floordiv() functions. Augmented
191 assignment variants are included, as are the equivalent overloadable
192 methods and C API methods. See the PEP for a full discussion:
193 <http://python.sf.net/peps/pep-0238.html>
194
Tim Peters6cd6a822001-08-17 22:11:27 +0000195- Future statements are now effective in simulated interactive shells
196 (like IDLE). This should "just work" by magic, but read Michael
197 Hudson's "Future statements in simulated shells" PEP 264 for full
198 details: <http://python.sf.net/peps/pep-0264.html>.
199
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000200- The type/class unification (PEP 252-253) was integrated into the
201 trunk and is not so tentative any more (the exact specification of
202 some features is still tentative). A lot of work has done on fixing
203 bugs and adding robustness and features (performance still has to
204 come a long way).
205
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000206- Warnings about a mismatch in the Python API during extension import
207 now use the Python warning framework (which makes it possible to
208 write filters for these warnings).
209
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000210- A function's __dict__ (aka func_dict) will now always be a
211 dictionary. It used to be possible to delete it or set it to None,
212 but now both actions raise TypeErrors. It is still legal to set it
213 to a dictionary object. Getting func.__dict__ before any attributes
214 have been assigned now returns an empty dictionary instead of None.
215
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000216Library
217
Tim Peters5e824c32001-08-12 22:25:01 +0000218- New class Differ and new functions ndiff() and restore() in difflib.py.
219 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000220 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000221
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000222- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
223 value using the minimal quoting required for the value; more
224 reliable than using xml.sax.saxutils.escape() for attribute values.
225
226- Readline completion support for cmd.Cmd was added.
227
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000228- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
229
230- Added function threading.BoundedSemaphore()
231
232- Added Ka-Ping Yee's cgitb.py module.
233
234- The `new' module now exposes the CO_xxx flags.
235
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000236New platforms
237
238C API
239
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000240- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
241 which provide a cross-platform implementations for the
242 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
243 the standard sprintf() and vsprintf() C lib APIs, these versions
244 apply bounds checking on the used buffer which enhances protection
245 against buffer overruns.
246
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000247- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000248 and extensions using different Unicode widths is rendered next to
249 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000250 will result in an ImportError. Unicode extensions writers must make
251 sure to check the Unicode width compatibility in their extensions by
252 using at least one of the mangled Unicode APIs in the extension.
253
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000254- Two new flags METH_NOARGS and METH_O are available in method definition
255 tables to simplify implementation of methods with no arguments and a
256 single untyped argument. Calling such methods is more efficient than
257 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
258 deprecated.
259
Tim Petersc1731372001-08-04 08:12:36 +0000260Windows
261
262- "import module" now compiles module.pyw if it exists and nothing else
263 relevant is found.
264
Tim Peters20f51a72001-07-21 02:31:40 +0000265
Guido van Rossum55a78992001-07-17 17:22:32 +0000266What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +0000267===========================
268
269Core
Tim Petersa814db52001-05-14 07:05:58 +0000270
Tim Peters6d6c1a32001-08-02 04:15:00 +0000271- TENTATIVELY, a large amount of code implementing much of what's
272 described in PEP 252 (Making Types Look More Like Classes) and PEP
273 253 (Subtyping Built-in Types) was added. This will be released
274 with Python 2.2a1. Documentation will be provided separately
275 through http://www.python.org/2.2/. The purpose of releasing this
276 with Python 2.2a1 is to test backwards compatibility. It is
277 possible, though not likely, that a decision is made not to release
278 this code as part of 2.2 final, if any serious backwards
279 incompapatibilities are found during alpha testing that cannot be
280 repaired.
281
Guido van Rossum55a78992001-07-17 17:22:32 +0000282- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000283 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000284 more 'yield' statements. See PEP 255. Since this adds a new
285 keyword to the language, this feature must be enabled by including a
286 future statement: "from __future__ import generators" (see PEP 236).
287 Generators will become a standard feature in a future release
288 (probably 2.3). Without this future statement, 'yield' remains an
289 ordinary identifier, but a warning is issued each time it is used.
290 (These warnings currently don't conform to the warnings framework of
291 PEP 230; we intend to fix this in 2.2a2.)
292
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000293- The UTF-16 codec was modified to be more RFC compliant. It will now
294 only remove BOM characters at the start of the string and then
295 only if running in native mode (UTF-16-LE and -BE won't remove a
296 leading BMO character).
297
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000298- Strings now have a new method .decode() to complement the already
299 existing .encode() method. These two methods provide direct access
300 to the corresponding decoders and encoders of the registered codecs.
301
302 To enhance the usability of the .encode() method, the special
303 casing of Unicode object return values was dropped (Unicode objects
304 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000305
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000306 Both methods will now return whatever the codec in charge of the
307 requested encoding returns as object, e.g. Unicode codecs will
308 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
309 will return u"äöü"). This enables codec writer to create codecs
310 for various simple to use conversions.
311
312 New codecs were added to demonstrate these new features (the .encode()
313 and .decode() columns indicate the type of the returned objects):
314
315 Name | .encode() | .decode() | Description
316 ----------------------------------------------------------------------
317 uu | string | string | UU codec (e.g. for email)
318 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000319 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000320 zlib | string | string | zlib compression
321 hex | string | string | 2-byte hex codec
322 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
323
Mark Hammond2a0af792001-05-14 03:09:36 +0000324- Some operating systems now support the concept of a default Unicode
325 encoding for file system operations. Notably, Windows supports 'mbcs'
326 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000327 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000328 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000329
330 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000331 functions that return filenames (such as os.listdir()) to return Python
332 string objects pre-encoded using the default file system encoding for
333 the platform. As this encoding is likely to be different from Python's
334 default encoding, converting this name to a Unicode object before passing
335 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000336 would attempt to use its default encoding (generally ASCII) rather than
337 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000338
Tim Petersa814db52001-05-14 07:05:58 +0000339 In general, this change simply removes surprises when working with
340 Unicode and the file system, making these operations work as you expect,
341 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000342 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000343
Tim Peters61dff2b2001-05-08 15:43:37 +0000344- Float (and complex) literals in source code were evaluated to full
345 precision only when running from a .py file; the same code loaded from a
346 .pyc (or .pyo) file could suffer numeric differences starting at about the
347 12th significant decimal digit. For example, on a machine with IEEE-754
348 floating arithmetic,
349
350 x = 9007199254740992.0
351 print long(x)
352
353 printed 9007199254740992 if run directly from .py, but 9007199254740000
354 if from a compiled (.pyc or .pyo) file. This was due to marshal using
355 str(float) instead of repr(float) when building code objects. marshal
356 now uses repr(float) instead, which should reproduce floats to full
357 machine precision (assuming the platform C float<->string I/O conversion
358 functions are of good quality).
359
360 This may cause floating-point results to change in some cases, and
361 usually for the better, but may also cause numerically unstable
362 algorithms to break.
363
Tim Peters2f228e72001-05-13 00:19:31 +0000364- The implementation of dicts suffers fewer collisions, which has speed
365 benefits. However, the order in which dict entries appear in dict.keys(),
366 dict.values() and dict.items() may differ from previous releases for a
367 given dict. Nothing is defined about this order, so no program should
368 rely on it. Nevertheless, it's easy to write test cases that rely on the
369 order by accident, typically because of printing the str() or repr() of a
370 dict to an "expected results" file. See Lib/test/test_support.py's new
371 sortdict(dict) function for a simple way to display a dict in sorted
372 order.
373
Tim Peters7a3bfc32001-06-12 01:22:22 +0000374- Many other small changes to dicts were made, resulting in faster
375 operation along the most common code paths.
376
Guido van Rossum10315822001-05-01 20:54:30 +0000377- Dictionary objects now support the "in" operator: "x in dict" means
378 the same as dict.has_key(x).
379
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000380- The update() method of dictionaries now accepts generic mapping
381 objects. Specifically the argument object must support the .keys()
382 and __getitem__() methods. This allows you to say, for example,
383 {}.update(UserDict())
384
Guido van Rossum10315822001-05-01 20:54:30 +0000385- Iterators were added; this is a generalized way of providing values
386 to a for loop. See PEP 234. There's a new built-in function iter()
387 to return an iterator. There's a new protocol to get the next value
388 from an iterator using the next() method (in Python) or the
389 tp_iternext slot (in C). There's a new protocol to get iterators
390 using the __iter__() method (in Python) or the tp_iter slot (in C).
391 Iterating (i.e. a for loop) over a dictionary generates its keys.
392 Iterating over a file generates its lines.
393
Tim Petersf553f892001-05-01 20:45:31 +0000394- The following functions were generalized to work nicely with iterator
395 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000396 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000397 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
398 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000399 join() method of strings
400 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000401 'x in y' and 'x not in y' (PySequence_Contains() in C API)
402 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000403 right-hand side of assignment statements with multiple targets, such as
404 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000405
Tim Petersd85e1022001-05-11 21:51:48 +0000406- Accessing module attributes is significantly faster (for example,
407 random.random or os.path or yourPythonModule.yourAttribute).
408
Tim Peterse63415e2001-05-08 04:38:29 +0000409- Comparing dictionary objects via == and != is faster, and now works even
410 if the keys and values don't support comparisons other than ==.
411
Tim Peters95bf9392001-05-10 08:32:44 +0000412- Comparing dictionaries in ways other than == and != is slower: there were
413 insecurities in the dict comparison implementation that could cause Python
414 to crash if the element comparison routines for the dict keys and/or
415 values mutated the dicts. Making the code bulletproof slowed it down.
416
Tim Peterseb28ef22001-06-02 05:27:19 +0000417- Collisions in dicts are resolved via a new approach, which can help
418 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000419 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000420 faster now. Thanks to Christian Tismer for pointing out the cause and
421 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000422
Tim Peters52e155e2001-06-16 05:42:57 +0000423- repr() is much faster for large containers (dict, list, tuple).
424
425
Tim Petersa814db52001-05-14 07:05:58 +0000426Library
427
Fred Drake960fdf92001-07-20 18:38:26 +0000428- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
429 were added to the string module. These a locale-indenpendent
430 constants, unlike letters, lowercase, and uppercase. These are now
431 use in appropriate locations in the standard library.
432
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000433- The flags used in dlopen calls can now be configured using
434 sys.setdlopenflags and queried using sys.getdlopenflags.
435
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000436- Fredrik Lundh's xmlrpclib is now a standard library module. This
437 provides full client-side XML-RPC support. In addition,
438 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
439 one asyncore-based). Thanks to Eric Raymond for the documentation.
440
Guido van Rossum643d3912001-07-05 14:46:25 +0000441- The xrange() object is simplified: it no longer supports slicing,
442 repetition, comparisons, efficient 'in' checking, the tolist()
443 method, or the start, stop and step attributes. See PEP 260.
444
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000445- A new function fnmatch.filter to filter lists of file names was added.
446
Barry Warsawffd674d2001-05-22 16:00:10 +0000447- calendar.py uses month and day names based on the current locale.
448
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000449- strop is now *really* obsolete (this was announced before with 1.6),
450 and issues DeprecationWarning when used (except for the four items
451 that are still imported into string.py).
452
Tim Petersa814db52001-05-14 07:05:58 +0000453- Cookie.py now sorts key+value pairs by key in output strings.
454
455- pprint.isrecursive(object) didn't correctly identify recursive objects.
456 Now it does.
457
Tim Peters95b3f782001-05-14 18:39:41 +0000458- pprint functions now much faster for large containers (tuple, list, dict).
459
Tim Peters7b9542a2001-06-10 23:40:19 +0000460- New 'q' and 'Q' format codes in the struct module, corresponding to C
461 types "long long" and "unsigned long long" (on Windows, __int64). In
462 native mode, these can be used only when the platform C compiler supports
463 these types (when HAVE_LONG_LONG is #define'd by the Python config
464 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000465 In standard mode, 'q' and 'Q' are supported on all platforms, and are
466 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000467
Guido van Rossum83213cc2001-06-12 16:48:52 +0000468- The site module installs a new built-in function 'help' that invokes
469 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
470 it displays a message reminding the user to use 'help()' or
471 'help(object)'.
472
Tim Petersa814db52001-05-14 07:05:58 +0000473Tests
474
475- New test_mutants.py runs dict comparisons where the key and value
476 comparison operators mutute the dicts randomly during comparison. This
477 rapidly causes Python to crash under earlier releases (not for the faint
478 of heart: it can also cause Win9x to freeze or reboot!).
479
480- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000481 pprint.isreadable() return sensible results. Also verifies that simple
482 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000483
Tim Peters4324aa32001-05-28 22:30:08 +0000484C API
485
486- Removed the unused last_is_sticky argument from the internal
487 _PyTuple_Resize(). If this affects you, you were cheating.
488
489
Guido van Rossum55a78992001-07-17 17:22:32 +0000490======================================================================
491
492
Guido van Rossumffe13be2001-04-16 18:46:45 +0000493What's New in Python 2.1 (final)?
494=================================
495
496We only changed a few things since the last release candidate, all in
497Python library code:
498
499- A bug in the locale module was fixed that affected locales which
500 define no grouping for numeric formatting.
501
502- A few bugs in the weakref module's implementations of weak
503 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
504 and the test suite was updated to check for these bugs.
505
506- An old bug in the os.path.walk() function (introduced in Python
507 2.0!) was fixed: a non-existent file would cause an exception
508 instead of being ignored.
509
510- Fixed a few bugs in the new symtable module found by Neil Norwitz's
511 PyChecker.
512
513
Guido van Rossum5b08f132001-04-16 02:05:23 +0000514What's New in Python 2.1c2?
515===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000516
Guido van Rossum5b08f132001-04-16 02:05:23 +0000517A flurry of small changes, and one showstopper fixed in the nick of
518time made it necessary to release another release candidate. The list
519here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000520
Guido van Rossum5b08f132001-04-16 02:05:23 +0000521Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000522
Guido van Rossum5b08f132001-04-16 02:05:23 +0000523- Tim discovered a nasty bug in the dictionary code, caused by
524 PyDict_Next() calling dict_resize(), and the GC code's use of
525 PyDict_Next() violating an assumption in dict_items(). This was
526 fixed with considerable amounts of band-aid, but the net effect is a
527 saner and more robust implementation.
528
529- Made a bunch of symbols static that were accidentally global.
530
531Build and Ports
532
533- The setup.py script didn't check for a new enough version of zlib
534 (1.1.3 is needed). Now it does.
535
536- Changed "make clean" target to also remove shared libraries.
537
538- Added a more general warning about the SGI Irix optimizer to README.
539
540Library
541
542- Fix a bug in urllib.basejoin("http://host", "../file.html") which
543 omitted the slash between host and file.html.
544
545- The mailbox module's _Mailbox class contained a completely broken
546 and undocumented seek() method. Ripped it out.
547
548- Fixed a bunch of typos in various library modules (urllib2, smtpd,
549 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
550
551- Fixed a few last-minute bugs in unittest.
552
553Extensions
554
555- Reverted the patch to the OpenSSL code in socketmodule.c to support
556 RAND_status() and the EGD, and the subsequent patch that tried to
557 fix it for pre-0.9.5 versions; the problem with the patch is that on
558 some systems it issues a warning whenever socket is imported, and
559 that's unacceptable.
560
561Tests
562
563- Fixed the pickle tests to work with "import test.test_pickle".
564
565- Tweaked test_locale.py to actually run the test Windows.
566
567- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
568 not "wb" (which is not a valid mode at all).
569
570- Fix pstats browser crashes. Import readline if it exists to make
571 the user interface nicer.
572
573- Add "import thread" to the top of test modules that import the
574 threading module (test_asynchat and test_threadedtempfile). This
575 prevents test failures caused by a broken threading module resulting
576 from a previously caught failed import.
577
578- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
579 needed on some platforms (e.g. Solaris 8) when the tests are run
580 twice in succession.
581
582- Skip rather than fail test_sunaudiodev if no audio device is found.
583
584
585What's New in Python 2.1c1?
586===========================
587
588This list was significantly updated when 2.1c2 was released; the 2.1c1
589release didn't mention most changes that were actually part of 2.1c1:
590
591Legal
592
593- Copyright was assigned to the Python Software Foundation (PSF) and a
594 PSF license (very similar to the CNRI license) was added.
595
596- The CNRI copyright notice was updated to include 2001.
597
598Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000599
Guido van Rossumc9932722001-04-12 02:31:27 +0000600- After a public outcry, assignment to __debug__ is no longer illegal;
601 instead, a warning is issued. It will become illegal in 2.2.
602
Guido van Rossum5b08f132001-04-16 02:05:23 +0000603- Fixed a core dump with "%#x" % 0, and changed the semantics so that
604 "%#x" now always prepends "0x", even if the value is zero.
605
606- Fixed some nits in the bytecode compiler.
607
608- Fixed core dumps when calling certain kinds of non-functions.
609
610- Fixed various core dumps caused by reference count bugs.
611
612Build and Ports
613
614- Use INSTALL_SCRIPT to install script files.
615
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000616- New port: SCO Unixware 7, by Billy G. Allie.
617
Guido van Rossum5b08f132001-04-16 02:05:23 +0000618- Updated RISCOS port.
619
620- Updated BeOS port and notes.
621
622- Various other porting problems resolved.
623
624Library
625
626- The TERMIOS and SOCKET modules are now truly obsolete and
627 unnecessary. Their symbols are incorporated in the termios and
628 socket modules.
629
630- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
631 better tests for pickling.
632
633- threading: make Condition.wait() robust against KeyboardInterrupt.
634
635- zipfile: add support to zipfile to support opening an archive
636 represented by an open file rather than a file name. Fix bug where
637 the archive was not properly closed. Fixed a bug in this bugfix
638 where flush() was called for a read-only file.
639
640- imputil: added an uninstall() method to the ImportManager.
641
642- Canvas: fixed bugs in lower() and tkraise() methods.
643
644- SocketServer: API change (added overridable close_request() method)
645 so that the TCP server can explicitly close the request.
646
647- pstats: Eric Raymond added a simple interactive statistics browser,
648 invoked when the module is run as a script.
649
650- locale: fixed a problem in format().
651
652- webbrowser: made it work when the BROWSER environment variable has a
653 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
654 KDE 2. Fixed some other nits.
655
656- unittest: changes to allow using a different exception than
657 AssertionError, and added a few more function aliases. Some other
658 small changes.
659
660- urllib, urllib2: fixed redirect problems and a coupleof other nits.
661
662- asynchat: fixed a critical bug in asynchat that slipped through the
663 2.1b2 release. Fixed another rare bug.
664
665- Fix some unqualified except: clauses (always a bad code example).
666
667XML
668
669- pyexpat: new API get_version_string().
670
671- Fixed some minidom bugs.
672
673Extensions
674
675- Fixed a core dump in _weakref. Removed the weakref.mapping()
676 function (it adds nothing to the API).
677
678- Rationalized the use of header files in the readline module, to make
679 it compile (albeit with some warnings) with the very recent readline
680 4.2, without breaking for earlier versions.
681
682- Hopefully fixed a buffering problem in linuxaudiodev.
683
684- Attempted a fix to make the OpenSSL support in the socket module
685 work again with pre-0.9.5 versions of OpenSSL.
686
687Tests
688
689- Added a test case for asynchat and asyncore.
690
691- Removed coupling between tests where one test failing could break
692 another.
693
694Tools
695
696- Ping added an interactive help browser to pydoc, fixed some nits
697 in the rest of the pydoc code, and added some features to his
698 inspect module.
699
700- An updated python-mode.el version 4.1 which integrates Ken
701 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
702 much nicer in XEmacs and Emacs. When stepping through your program
703 with pdb, in either the shell window or the *Python* window, the
704 source file and line will be tracked by an arrow. Very cool!
705
706- IDLE: syntax warnings in interactive mode are changed into errors.
707
708- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +0000709 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +0000710
711- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000712
Barry Warsaw11e89c72001-04-11 20:37:57 +0000713
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000714What's New in Python 2.1 beta 2?
715================================
716
Guido van Rossum053ae352001-03-22 14:17:21 +0000717(Unlisted are many fixed bugs, more documentation, etc.)
718
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000719Core language, builtins, and interpreter
720
Guido van Rossum053ae352001-03-22 14:17:21 +0000721- The nested scopes work (enabled by "from __future__ import
722 nested_scopes") is completed; in particular, the future now extends
723 into code executed through exec, eval() and execfile(), and into the
724 interactive interpreter.
725
726- When calling a base class method (e.g. BaseClass.__init__(self)),
727 this is now allowed even if self is not strictly spoken a class
728 instance (e.g. when using metaclasses or the Don Beaudry hook).
729
730- Slice objects are now comparable but not hashable; this prevents
731 dict[:] from being accepted but meaningless.
732
733- Complex division is now calculated using less braindead algorithms.
734 This doesn't change semantics except it's more likely to give useful
735 results in extreme cases. Complex repr() now uses full precision
736 like float repr().
737
738- sgmllib.py now calls handle_decl() for simple <!...> declarations.
739
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000740- It is illegal to assign to the name __debug__, which is set when the
741 interpreter starts. It is effectively a compile-time constant.
742
743- A warning will be issued if a global statement for a variable
744 follows a use or assignment of that variable.
745
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000746Standard library
747
Guido van Rossum053ae352001-03-22 14:17:21 +0000748- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
749 inspired by JUnit), is now part of the standard library. You now
750 have a choice of two testing frameworks: unittest requires you to
751 write testcases as separate code, doctest gathers them from
752 docstrings. Both approaches have their advantages and
753 disadvantages.
754
755- A new module Tix was added, which wraps the Tix extension library
756 for Tk. With that module, it is not necessary to statically link
757 Tix with _tkinter, since Tix will be loaded with Tcl's "package
758 require" command. See Demo/tix/.
759
760- tzparse.py is now obsolete.
761
762- In gzip.py, the seek() and tell() methods are removed -- they were
763 non-functional anyway, and it's better if callers can test for their
764 existence with hasattr().
765
766Python/C API
767
768- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
769 that's already in the dictionary during a PyDict_Next() iteration.
770 This used to fail occasionally when a dictionary resize operation
771 could be triggered that would rehash all the keys. All other
772 modifications to the dictionary are still off-limits during a
773 PyDict_Next() iteration!
774
775- New extended APIs related to passing compiler variables around.
776
777- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
778 implement isinstance() and issubclass().
779
780- Py_BuildValue() now has a "D" conversion to create a Python complex
781 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000782
Fred Drake4e262a92001-03-22 18:26:47 +0000783- Extensions types which support weak references must now set the
784 field allocated for the weak reference machinery to NULL themselves;
785 this is done to avoid the cost of checking each object for having a
786 weakly referencable type in PyObject_INIT(), since most types are
787 not weakly referencable.
788
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000789- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
790 free variables and cell variables to and from the frame's f_locals.
791
792- Variants of several functions defined in pythonrun.h have been added
793 to support the nested_scopes future statement. The variants all end
794 in Flags and take an extra argument, a PyCompilerFlags *; examples:
795 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
796 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +0000797 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000798
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000799Distutils
800
801- the sdist command now writes a PKG-INFO file, as described in PEP 241,
802 into the release tree.
803
Tim Peters0e57abf2001-05-02 07:39:38 +0000804- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000805 (an uninstaller, more customization of the installer's display)
806
807- from Jack Jansen: added Mac-specific code to generate a dialog for
808 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +0000809 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000810 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +0000811
812- added 'platforms' and 'keywords' to the set of metadata that can be
813 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000814
815- applied patches from Jason Tishler to make the compiler class work with
816 Cygwin.
817
818
Tim Peters2fe289a2001-03-01 22:19:38 +0000819What's New in Python 2.1 beta 1?
820================================
Tim Petersd66595f2001-02-04 03:09:53 +0000821
822Core language, builtins, and interpreter
823
Guido van Rossum9d0fbde2001-03-02 14:00:32 +0000824- Following an outcry from the community about the amount of code
825 broken by the nested scopes feature introduced in 2.1a2, we decided
826 to make this feature optional, and to wait until Python 2.2 (or at
827 least 6 months) to make it standard. The option can be enabled on a
828 per-module basis by adding "from __future__ import nested_scopes" at
829 the beginning of a module (before any other statements, but after
830 comments and an optional docstring). See PEP 236 (Back to the
831 __future__) for a description of the __future__ statement. PEP 227
832 (Statically Nested Scopes) has been updated to reflect this change,
833 and to clarify the semantics in a number of endcases.
834
835- The nested scopes code, when enabled, has been hardened, and most
836 bugs and memory leaks in it have been fixed.
837
838- Compile-time warnings are now generated for a number of conditions
839 that will break or change in meaning when nested scopes are enabled:
840
841 - Using "from...import *" or "exec" without in-clause in a function
842 scope that also defines a lambda or nested function with one or
843 more free (non-local) variables. The presence of the import* or
844 bare exec makes it impossible for the compiler to determine the
845 exact set of local variables in the outer scope, which makes it
846 impossible to determine the bindings for free variables in the
847 inner scope. To avoid the warning about import *, change it into
848 an import of explicitly name object, or move the import* statement
849 to the global scope; to avoid the warning about bare exec, use
850 exec...in... (a good idea anyway -- there's a possibility that
851 bare exec will be deprecated in the future).
852
853 - Use of a global variable in a nested scope with the same name as a
854 local variable in a surrounding scope. This will change in
855 meaning with nested scopes: the name in the inner scope will
856 reference the variable in the outer scope rather than the global
857 of the same name. To avoid the warning, either rename the outer
858 variable, or use a global statement in the inner function.
859
Neil Schemenauera35c6882001-02-27 04:45:05 +0000860- An optional object allocator has been included. This allocator is
861 optimized for Python objects and should be faster and use less memory
862 than the standard system allocator. It is not enabled by default
863 because of possible thread safety problems. The allocator is only
864 protected by the Python interpreter lock and it is possible that some
865 extension modules require a thread safe allocator. The object
866 allocator can be enabled by providing the "--with-pymalloc" option to
867 configure.
868
Tim Petersd66595f2001-02-04 03:09:53 +0000869Standard library
870
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000871- pyexpat now detects the expat version if expat.h defines it. A
872 number of additional handlers are provided, which are only available
873 since expat 1.95. In addition, the methods SetParamEntityParsing and
874 GetInputContext of Parser objects are available with 1.95.x
875 only. Parser objects now provide the ordered_attributes and
876 specified_attributes attributes. A new module expat.model was added,
877 which offers a number of additional constants if 1.95.x is used.
878
879- xml.dom offers the new functions registerDOMImplementation and
880 getDOMImplementation.
881
882- xml.dom.minidom offers a toprettyxml method. A number of DOM
883 conformance issues have been resolved. In particular, Element now
884 has an hasAttributes method, and the handling of namespaces was
885 improved.
886
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000887- Ka-Ping Yee contributed two new modules: inspect.py, a module for
888 getting information about live Python code, and pydoc.py, a module
889 for interactively converting docstrings to HTML or text.
890 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +0000891 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +0000892 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
893 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000894
Tim Peters1eff7962001-03-01 02:31:33 +0000895- New library module difflib.py, primarily packaging the SequenceMatcher
896 class at the heart of the popular ndiff.py file-comparison tool.
897
898- doctest.py (a framework for verifying Python code examples in docstrings)
899 is now part of the std library.
900
Tim Petersd66595f2001-02-04 03:09:53 +0000901Windows changes
902
Guido van Rossume3955a82001-03-02 14:05:59 +0000903- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
904 small GUI that lets you browse the module docstrings using your
905 default web browser.
906
Tim Peters1eff7962001-03-01 02:31:33 +0000907- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
908 Platforms) is implemented. See
909
910 http://python.sourceforge.net/peps/pep-0235.html
911
912 for full details, especially the "Current Lower-Left Semantics" section.
913 The new Windows import rules are simpler than before:
914
915 A. If the PYTHONCASEOK environment variable exists, same as
916 before: silently accept the first case-insensitive match of any
917 kind; raise ImportError if none found.
918
919 B. Else search sys.path for the first case-sensitive match; raise
920 ImportError if none found.
921
922 The same rules have been implented on other platforms with case-
923 insensitive but case-preserving filesystems too (including Cygwin, and
924 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +0000925
Tim Peters25a9ce32001-02-19 07:06:36 +0000926- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
927 what it's supposed to do (and does do under NT and 2000) via direct
928 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +0000929 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +0000930 all Win9x systems before.
931
Tim Peters1eff7962001-03-01 02:31:33 +0000932- Build: Subproject _test (effectively) renamed to _testcapi.
933
Tim Peters2fe289a2001-03-01 22:19:38 +0000934New platforms
935
936- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
937 Thanks to Steven Majewski!
938
939- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
940 Tishler!
941
Guido van Rossum9089b272001-03-02 06:49:50 +0000942- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
943 Schwertberger! See RISCOS/README for more information -- it seems
944 that because of the bizarre filename conventions on RISCOS, no port
945 to that platform is easy. Note that the new variable os.endsep is
946 silently supported in order to make life easier on this platform,
947 but we don't advertise it because it's not worth for most folks to
948 care about RISCOS portability.
949
Tim Peters25a9ce32001-02-19 07:06:36 +0000950
Tim Petersd7b5e882001-01-25 03:36:26 +0000951What's New in Python 2.1 alpha 2?
952=================================
Tim Peters40ead762001-01-27 05:35:26 +0000953
Tim Petersd7b5e882001-01-25 03:36:26 +0000954Core language, builtins, and interpreter
955
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000956- Scopes nest. If a name is used in a function or class, but is not
957 local, the definition in the nearest enclosing function scope will
958 be used. One consequence of this change is that lambda statements
959 could reference variables in the namespaces where the lambda is
960 defined. In some unusual cases, this change will break code.
961
962 In all previous version of Python, names were resolved in exactly
963 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000964 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000965 function A is defined within a function B, the names bound in B are
966 not visible in A. The new rules make names bound in B visible in A,
967 unless A contains a name binding that hides the binding in B.
968
969 Section 4.1 of the reference manual describes the new scoping rules
970 in detail. The test script in Lib/test/test_scope.py demonstrates
971 some of the effects of the change.
972
973 The new rules will cause existing code to break if it defines nested
974 functions where an outer function has local variables with the same
975 name as globals or builtins used by the inner function. Example:
976
977 def munge(str):
978 def helper(x):
979 return str(x)
980 if type(str) != type(''):
981 str = helper(str)
982 return str.strip()
983
984 Under the old rules, the name str in helper() is bound to the
985 builtin function str(). Under the new rules, it will be bound to
986 the argument named str and an error will occur when helper() is
987 called.
988
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000989- The compiler will report a SyntaxError if "from ... import *" occurs
990 in a function or class scope. The language reference has documented
991 that this case is illegal, but the compiler never checked for it.
992 The recent introduction of nested scope makes the meaning of this
993 form of name binding ambiguous. In a future release, the compiler
994 may allow this form when there is no possibility of ambiguity.
995
Tim Peters40ead762001-01-27 05:35:26 +0000996- repr(string) is easier to read, now using hex escapes instead of octal,
997 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
998
999 >>> "\texample \r\n" + chr(0) + chr(255)
1000 '\texample \r\n\x00\xff' # in 2.1
1001 '\011example \015\012\000\377' # in 2.0
1002
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001003- Functions are now compared and hashed by identity, not by value, since
1004 the func_code attribute is writable.
1005
Fred Drakefb9d7122001-02-01 20:00:40 +00001006- Weak references (PEP 205) have been added. This involves a few
1007 changes in the core, an extension module (_weakref), and a Python
1008 module (weakref). The weakref module is the public interface. It
1009 includes support for "explicit" weak references, proxy objects, and
1010 mappings with weakly held values.
1011
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001012- A 'continue' statement can now appear in a try block within the body
1013 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001014 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001015
Tim Petersd7b5e882001-01-25 03:36:26 +00001016Standard library
1017
Barry Warsaw30dbd142001-01-31 22:14:01 +00001018- mailbox.py now has a new class, PortableUnixMailbox which is
1019 identical to UnixMailbox but uses a more portable scheme for
1020 determining From_ separators. Also, the constructors for all the
1021 classes in this module have a new optional `factory' argument, which
1022 is a callable used when new message classes must be instantiated by
1023 the next() method.
1024
Tim Petersd7b5e882001-01-25 03:36:26 +00001025- random.py is now self-contained, and offers all the functionality of
1026 the now-deprecated whrandom.py. See the docs for details. random.py
1027 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001028 and restoring the internal state of the generator; and jumpahead(n),
1029 for quickly forcing the internal state to be the same as if n calls to
1030 random() had been made. The latter is particularly useful for multi-
1031 threaded programs, creating one instance of the random.Random() class for
1032 each thread, then using .jumpahead() to force each instance to use a
1033 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001034
Tim Peters0de88fc2001-02-01 04:59:18 +00001035- random.py's seed() function is new. For bit-for-bit compatibility with
1036 prior releases, use the whseed function instead. The new seed function
1037 addresses two problems: (1) The old function couldn't produce more than
1038 about 2**24 distinct internal states; the new one about 2**45 (the best
1039 that can be done in the Wichmann-Hill generator). (2) The old function
1040 sometimes produced identical internal states when passed distinct
1041 integers, and there was no simple way to predict when that would happen;
1042 the new one guarantees to produce distinct internal states for all
1043 arguments in [0, 27814431486576L).
1044
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001045- The socket module now supports raw packets on Linux. The socket
1046 family is AF_PACKET.
1047
Tim Peters9ea17ac2001-02-02 05:57:15 +00001048- test_capi.py is a start at running tests of the Python C API. The tests
1049 are implemented by the new Modules/_testmodule.c.
1050
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001051- A new extension module, _symtable, provides provisional access to the
1052 internal symbol table used by the Python compiler. A higher-level
1053 interface will be added on top of _symtable in a future release.
1054
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001055- Removed the obsolete soundex module.
1056
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001057- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1058 the isSameNode method; NamedNodeMap the get method.
1059
1060- xml.sax.expatreader supports the lexical handler property; it
1061 generates comment, startCDATA, and endCDATA events.
1062
Tim Petersee826f82001-01-31 19:39:44 +00001063Windows changes
1064
1065- Build procedure: the zlib project is built in a different way that
1066 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001067 the zlib binary used. See PCbuild\readme.txt for details. Your old
1068 zlib-related directories can be deleted; you'll need to download fresh
1069 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001070
Tim Peters9ea17ac2001-02-02 05:57:15 +00001071- Build: New subproject _test for the benefit of test_capi.py (see above).
1072
Tim Petersb16c56f2001-02-02 21:24:51 +00001073- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1074 interface to some Python compiler internals).
1075
1076- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001077 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001078
Tim Petersa3a3a032000-11-30 05:22:44 +00001079What's New in Python 2.1 alpha 1?
1080=================================
1081
1082Core language, builtins, and interpreter
1083
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001084- There is a new Unicode companion to the PyObject_Str() API
1085 called PyObject_Unicode(). It behaves in the same way as the
1086 former, but assures that the returned value is an Unicode object
1087 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001088
Guido van Rossumf98eda02001-01-17 15:54:45 +00001089- The comparison operators support "rich comparison overloading" (PEP
1090 207). C extension types can provide a rich comparison function in
1091 the new tp_richcompare slot in the type object. The cmp() function
1092 and the C function PyObject_Compare() first try the new rich
1093 comparison operators before trying the old 3-way comparison. There
1094 is also a new C API PyObject_RichCompare() (which also falls back on
1095 the old 3-way comparison, but does not constrain the outcome of the
1096 rich comparison to a Boolean result).
1097
1098 The rich comparison function takes two objects (at least one of
1099 which is guaranteed to have the type that provided the function) and
1100 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1101 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1102 object, which may be NotImplemented (in which case the tp_compare
1103 slot function is used as a fallback, if defined).
1104
1105 Classes can overload individual comparison operators by defining one
1106 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001107 __ge__. There are no explicit "reflected argument" versions of
1108 these; instead, __lt__ and __gt__ are each other's reflection,
1109 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1110 reflection (similar at the C level). No other implications are
1111 made; in particular, Python does not assume that == is the Boolean
1112 inverse of !=, or that < is the Boolean inverse of >=. This makes
1113 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001114
1115 Classes or types that want to implement (in)equality tests but not
1116 the ordering operators (i.e. unordered types) should implement ==
1117 and !=, and raise an error for the ordering operators.
1118
Guido van Rossuma88479f2001-01-18 14:28:08 +00001119 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001120 Boolean; e.g. a matrix type might want to return a matrix of bits
1121 for A < B, giving elementwise comparisons. Such types should ensure
1122 that any interpretation of their value in a Boolean context raises
1123 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1124 at the C level) to always raise an exception.
1125
Guido van Rossuma88479f2001-01-18 14:28:08 +00001126- Complex numbers use rich comparisons to define == and != but raise
1127 an exception for <, <=, > and >=. Unfortunately, this also means
1128 that cmp() of two complex numbers raises an exception when the two
1129 numbers differ. Since it is not mathematically meaningful to compare
1130 complex numbers except for equality, I hope that this doesn't break
1131 too much code.
1132
Tim Peters3389f192001-02-18 08:48:49 +00001133- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001134 not defined by the language, other than that it's arbitrary but
1135 consistent (see the Reference Manual). An implementation detail changed
1136 in 2.1a1 such that None now compares less than any other object. Code
1137 relying on this new behavior (like code that relied on the previous
1138 behavior) does so at its own risk.
1139
Barry Warsaw573b5412001-01-15 20:43:18 +00001140- Functions and methods now support getting and setting arbitrarily
1141 named attributes (PEP 232). Functions have a new __dict__
1142 (a.k.a. func_dict) which hold the function attributes. Methods get
1143 and set attributes on their underlying im_func. It is a TypeError
1144 to set an attribute on a bound method.
1145
Guido van Rossum051e3352001-01-15 19:11:10 +00001146- The xrange() object implementation has been improved so that
1147 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1148 limitation that in this case len(xrange(sys.maxint)) can't be
1149 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1150 work fine as long as the index i doesn't actually reach 2**31.
1151 (Python uses regular ints for sequence and string indices; fixing
1152 that is much more work.)
1153
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001154- Two changes to from...import:
1155
Guido van Rossumba381232001-02-03 15:06:40 +00001156 1) "from M import X" now works even if (after loading module M)
1157 sys.modules['M'] is not a real module; it's basically a getattr()
1158 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001159
1160 2) "from M import *" now looks for M.__all__ to decide which names to
1161 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1162 filters out names starting with '_' as before. Whether or not
1163 __all__ exists, there's no restriction on the type of M.
1164
Guido van Rossumf61f1662001-01-10 20:13:55 +00001165- File objects have a new method, xreadlines(). This is the fastest
1166 way to iterate over all lines in a file:
1167
1168 for line in file.xreadlines():
1169 ...do something to line...
1170
1171 See the xreadlines module (mentioned below) for how to do this for
1172 other file-like objects.
1173
1174- Even if you don't use file.xreadlines(), you may expect a speedup on
1175 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001176 quite a bit in platform-specific ways: on systems (like Linux) that
1177 support flockfile(), getc_unlocked(), and funlockfile(), those are
1178 used by default. On systems (like Windows) without getc_unlocked(),
1179 a complicated (but still thread-safe) method using fgets() is used by
1180 default.
1181
Tim Petersd52269b2001-01-25 06:23:18 +00001182 You can force use of the fgets() method by #define'ing
1183 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001184 getc_unlocked()).
1185
Tim Petersd52269b2001-01-25 06:23:18 +00001186 You can force fgets() not to be used by #define'ing
1187 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001188 test_bufio.py fails -- and let us know if it does!).
1189
1190- In addition, the fileinput module, while still slower than the other
1191 methods on most platforms, has been sped up too, by using
1192 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001193
1194- Support for run-time warnings has been added, including a new
1195 command line option (-W) to specify the disposition of warnings.
1196 See the description of the warnings module below.
1197
1198- Extensive changes have been made to the coercion code. This mostly
1199 affects extension modules (which can now implement mixed-type
1200 numerical operators without having to use coercion), but
1201 occasionally, in boundary cases the coercion semantics have changed
1202 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001203 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001204 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001205 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001206
Guido van Rossumf98eda02001-01-17 15:54:45 +00001207- In connection with the coercion changes, a new built-in singleton
1208 object, NotImplemented is defined. This can be returned for
1209 operations that wish to indicate they are not implemented for a
1210 particular combination of arguments. From C, this is
1211 Py_NotImplemented.
1212
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001213- The interpreter accepts now bytecode files on the command line even
1214 if they do not have a .pyc or .pyo extension. On Linux, after executing
1215
Martin v. Löwise214baa2001-02-04 22:37:56 +00001216import imp,sys,string
1217magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1218reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1219open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001220
1221 any byte code file can be used as an executable (i.e. as an argument
1222 to execve(2)).
1223
Tim Peters9940b802000-12-01 07:59:35 +00001224- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001225 character. In 1.6 and earlier, they never produced a sign,
1226 and raised an error if the value of the long was too large
1227 to fit in a Python int. In 2.0, they produced a sign if and
1228 only if too large to fit in an int. This was inconsistent
1229 across platforms (because the size of an int varies across
1230 platforms), and inconsistent with hex() and oct(). Example:
1231
1232 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001233 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001234 'ffffffbe' # in 2.0 and before, on 32-bit machines
1235 >>> hex(-0x42L)
1236 '-0x42L' # in all versions of Python
1237
Tim Peters9940b802000-12-01 07:59:35 +00001238 The behavior of %d formats for negative Python longs remains
1239 the same as in 2.0 (although in 1.6 and before, they raised
1240 an error if the long didn't fit in a Python int).
1241
1242 %u formats don't make sense for Python longs, but are allowed
1243 and treated the same as %d in 2.1. In 2.0, a negative long
1244 formatted via %u produced a sign if and only if too large to
1245 fit in an int. In 1.6 and earlier, a negative long formatted
1246 via %u raised an error if it was too big to fit in an int.
1247
Guido van Rossum3661d392000-12-12 22:10:31 +00001248- Dictionary objects have an odd new method, popitem(). This removes
1249 an arbitrary item from the dictionary and returns it (in the form of
1250 a (key, value) pair). This can be useful for algorithms that use a
1251 dictionary as a bag of "to do" items and repeatedly need to pick one
1252 item. Such algorithms normally end up running in quadratic time;
1253 using popitem() they can usually be made to run in linear time.
1254
Tim Peters36cdad12000-12-29 02:06:45 +00001255Standard library
1256
Thomas Woutersfe385252001-01-19 23:16:56 +00001257- In the time module, the time argument to the functions strftime,
1258 localtime, gmtime, asctime and ctime is now optional, defaulting to
1259 the current time (in the local timezone).
1260
Guido van Rossumda91f222001-01-15 16:36:08 +00001261- The ftplib module now defaults to passive mode, which is deemed a
1262 more useful default given that clients are often inside firewalls
1263 these days. Note that this could break if ftplib is used to connect
1264 to a *server* that is inside a firewall, from outside; this is
1265 expected to be a very rare situation. To fix that, you can call
1266 ftp.set_pasv(0).
1267
Martin v. Löwis10a27872001-01-13 09:54:41 +00001268- The module site now treats .pth files not only for path configuration,
1269 but also supports extensions to the initialization code: Lines starting
1270 with import are executed.
1271
Guido van Rossumf61f1662001-01-10 20:13:55 +00001272- There's a new module, warnings, which implements a mechanism for
1273 issuing and filtering warnings. There are some new built-in
1274 exceptions that serve as warning categories, and a new command line
1275 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1276 turns warnings into errors). warnings.warn(message[, category])
1277 issues a warning message; this can also be called from C as
1278 PyErr_Warn(category, message).
1279
1280- A new module xreadlines was added. This exports a single factory
1281 function, xreadlines(). The intention is that this code is the
1282 absolutely fastest way to iterate over all lines in an open
1283 file(-like) object:
1284
1285 import xreadlines
1286 for line in xreadlines.xreadlines(file):
1287 ...do something to line...
1288
1289 This is equivalent to the previous the speed record holder using
1290 file.readlines(sizehint). Note that if file is a real file object
1291 (as opposed to a file-like object), this is equivalent:
1292
1293 for line in file.xreadlines():
1294 ...do something to line...
1295
Tim Peters36cdad12000-12-29 02:06:45 +00001296- The bisect module has new functions bisect_left, insort_left,
1297 bisect_right and insort_right. The old names bisect and insort
1298 are now aliases for bisect_right and insort_right. XXX_right
1299 and XXX_left methods differ in what happens when the new element
1300 compares equal to one or more elements already in the list: the
1301 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001302 right. Code that doesn't care where equal elements end up should
1303 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001304
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001305- The new curses.panel module wraps the panel library that forms part
1306 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1307
Guido van Rossumf61f1662001-01-10 20:13:55 +00001308- The SocketServer module now sets the allow_reuse_address flag by
1309 default in the TCPServer class.
1310
1311- A new function, sys._getframe(), returns the stack frame pointer of
1312 the caller. This is intended only as a building block for
1313 higher-level mechanisms such as string interpolation.
1314
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001315- The pyexpat module supports a number of new handlers, which are
1316 available only in expat 1.2. If invocation of a callback fails, it
1317 will report an additional frame in the traceback. Parser objects
1318 participate now in garbage collection. If expat reports an unknown
1319 encoding, pyexpat will try to use a Python codec; that works only
1320 for single-byte charsets. The parser type objects is exposed as
1321 XMLParserObject.
1322
1323- xml.dom now offers standard definitions for symbolic node type and
1324 exception code constants, and a hierarchy of DOM exceptions. minidom
1325 was adjusted to use them.
1326
1327- The conformance of xml.dom.minidom to the DOM specification was
1328 improved. It detects a number of additional error cases; the
1329 previous/next relationship works even when the tree is modified;
1330 Node supports the normalize() method; NamedNodeMap, DocumentType and
1331 DOMImplementation classes were added; Element supports the
1332 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1333 method.
1334
Guido van Rossumf61f1662001-01-10 20:13:55 +00001335Build issues
1336
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001337- For Unix (and Unix-compatible) builds, configuration and building of
1338 extension modules is now greatly automated. Rather than having to
1339 edit the Modules/Setup file to indicate which modules should be
1340 built and where their include files and libraries are, a
1341 distutils-based setup.py script now takes care of building most
1342 extension modules. All extension modules built this way are built
1343 as shared libraries. Only a few modules that must be linked
1344 statically are still listed in the Setup file; you won't need to
1345 edit their configuration.
1346
1347- Python should now build out of the box on Cygwin. If it doesn't,
1348 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001349
1350- Python now always uses its own (renamed) implementation of getopt()
1351 -- there's too much variation among C library getopt()
1352 implementations.
1353
1354- C++ compilers are better supported; the CXX macro is always set to a
1355 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001356
Tim Petersd92dfe02000-12-12 01:18:41 +00001357Windows changes
1358
1359- select module: By default under Windows, a select() call
1360 can specify no more than 64 sockets. Python now boosts
1361 this Microsoft default to 512. If you need even more than
1362 that, see the MS docs (you'll need to #define FD_SETSIZE
1363 and recompile Python from source).
1364
Guido van Rossumf61f1662001-01-10 20:13:55 +00001365- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1366 subdirectory is no more!
1367
Tim Petersa3a3a032000-11-30 05:22:44 +00001368
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001369What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001370=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001371
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001372Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001373changes are in the file HISTORY. If you are making the jump directly
1374from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1375HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001376
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001377Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1378the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1379http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001380
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001381--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001382
1383======================================================================
1384
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001385What's new in 2.0 (since release candidate 1)?
1386==============================================
1387
1388Standard library
1389
1390- The copy_reg module was modified to clarify its intended use: to
1391 register pickle support for extension types, not for classes.
1392 pickle() will raise a TypeError if it is passed a class.
1393
1394- Fixed a bug in gettext's "normalize and expand" code that prevented
1395 it from finding an existing .mo file.
1396
1397- Restored support for HTTP/0.9 servers in httplib.
1398
Tim Peters989b7b92000-10-16 20:24:53 +00001399- The math module was changed to stop raising OverflowError in case of
1400 underflow, and return 0 instead in underflow cases. Whether Python
1401 used to raise OverflowError in case of underflow was platform-
1402 dependent (it did when the platform math library set errno to ERANGE
1403 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001404
1405- Fixed a bug in StringIO that occurred when the file position was not
1406 at the end of the file and write() was called with enough data to
1407 extend past the end of the file.
1408
1409- Fixed a bug that caused Tkinter error messages to get lost on
1410 Windows. The bug was fixed by replacing direct use of
1411 interp->result with Tcl_GetStringResult(interp).
1412
1413- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1414 redirect response.
1415
1416- Several changes were made to distutils: Some debugging code was
1417 removed from util. Fixed the installer used when an external zip
1418 program (like WinZip) is not found; the source code for this
1419 installer is in Misc/distutils. check_lib() was modified to behave
1420 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1421 test for whether installed modules are on sys.path was changed to
1422 use both normcase() and normpath().
1423
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001424- Several minor bugs were fixed in the xml package (the minidom,
1425 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001426
1427- The regression test driver (regrtest.py) behavior when invoked with
1428 -l changed: It now reports a count of objects that are recognized as
1429 garbage but not freed by the garbage collector.
1430
Tim Peters989b7b92000-10-16 20:24:53 +00001431- The regression test for the math module was changed to test
1432 exceptional behavior when the test is run in verbose mode. Python
1433 cannot yet guarantee consistent exception behavior across platforms,
1434 so the exception part of test_math is run only in verbose mode, and
1435 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001436
1437Internals
1438
1439- PyOS_CheckStack() has been disabled on Win64, where it caused
1440 test_sre to fail.
1441
1442Build issues
1443
1444- Changed compiler flags, so that gcc is always invoked with -Wall and
1445 -Wstrict-prototypes. Users compiling Python with GCC should see
1446 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001447 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001448 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001449
Tim Petersa3a3a032000-11-30 05:22:44 +00001450- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001451
1452Tools and other miscellany
1453
1454- The compiler in Tools/compiler was updated to support the new
1455 language features introduced in 2.0: extended print statement, list
1456 comprehensions, and augmented assignments. The new compiler should
1457 also be backwards compatible with Python 1.5.2; the compiler will
1458 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001459 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001460
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001461What's new in 2.0 release candidate 1 (since beta 2)?
1462=====================================================
1463
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001464What is release candidate 1?
1465
1466We believe that release candidate 1 will fix all known bugs that we
1467intend to fix for the 2.0 final release. This release should be a bit
1468more stable than the previous betas. We would like to see even more
1469widespread testing before the final release, so we are producing this
1470release candidate. The final release will be exactly the same unless
1471any show-stopping (or brown bag) bugs are found by testers of the
1472release candidate.
1473
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001474All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001475to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001476
1477Core language, builtins, and interpreter
1478
1479- A bug that caused crashes when __coerce__ was used with augmented
1480 assignment, e.g. +=, was fixed.
1481
1482- Raise ZeroDivisionError when raising zero to a negative number,
1483 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1484 power operator and the result of math.pow(0.0, -2.0) will vary by
1485 platform. On Linux, it raises a ValueError.
1486
1487- A bug in Unicode string interpolation was fixed that occasionally
1488 caused errors with formats including "%%". For example, the
1489 following expression "%% %s" % u"abc" no longer raises a TypeError.
1490
1491- Compilation of deeply nested expressions raises MemoryError instead
1492 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1493
1494- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1495 rendering them useless. They are now written in binary mode again.
1496
1497Standard library
1498
1499- Keyword arguments are now accepted for most pattern and match object
1500 methods in SRE, the standard regular expression engine.
1501
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001502- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001503 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001504
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001505- Several bugs in the Unicode handling and error handling in _tkinter
1506 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001507
1508- Fix memory management errors in Merge() and Tkapp_Call() routines.
1509
1510- Several changes were made to cStringIO to make it compatible with
1511 the file-like object interface and with StringIO. If operations are
1512 performed on a closed object, an exception is raised. The truncate
1513 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001514 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001515
1516- There were many changes made to the linuxaudiodev module and its
1517 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001518 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001519
1520 Note that this module is named poorly, because it should work
1521 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001522 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001523
1524 The module now raises exceptions when errors occur instead of
1525 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1526 audio) and defines a getptr() method that calls the
1527 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1528
1529- The library_version attribute, introduced in an earlier beta, was
1530 removed because it can not be supported with early versions of the C
1531 readline library, which provides no way to determine the version at
1532 compile-time.
1533
1534- The binascii module is now enabled on Win64.
1535
Tim Peters46446d62000-10-09 21:19:31 +00001536- tokenize.py no longer suffers "recursion depth" errors when parsing
1537 programs with very long string literals.
1538
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001539Internals
1540
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001541- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001542 which is called when the interpreter starts up to determine where
1543 the standard library is installed. These vulnerabilities affect all
1544 previous versions of Python and can be exploited by setting very
1545 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1546 setuid Python script, although use of the wrapper in
1547 Misc/setuid-prog.c will eliminate the vulnerability.
1548
1549- Fixed garbage collection bugs in instance creation that were
1550 triggered when errors occurred during initialization. The solution,
1551 applied in cPickle and in PyInstance_New(), is to call
1552 PyObject_GC_Init() after the initialization of the object's
1553 container attributes is complete.
1554
1555- pyexpat adds definitions of PyModule_AddStringConstant and
1556 PyModule_AddObject if the Python version is less than 2.0, which
1557 provides compatibility with PyXML on Python 1.5.2.
1558
1559- If the platform has a bogus definition for LONG_BIT (the number of
1560 bits in a long), an error will be reported at compile time.
1561
1562- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1563 collection crashes and possibly other, unreported crashes.
1564
1565- Fixed a memory leak in _PyUnicode_Fini().
1566
1567Build issues
1568
1569- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001570 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001571 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001572
1573- The mmap.PAGESIZE constant is now initialized using sysconf when
1574 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1575
1576- The md5 file should now compile on all platforms.
1577
1578- The select module now compiles on platforms that do not define
1579 POLLRDNORM and related constants.
1580
1581- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001582 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001583
Jeremy Hylton10921202000-10-09 18:34:12 +00001584- BeOS: A number of changes were made to the build and installation
1585 process. ar-fake now operates on a directory of object files.
1586 dl_export.h is gone, and its macros now appear on the mwcc command
1587 line during build on PPC BeOS.
1588
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001589- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001590 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001591
1592- Cygwin: Support for shared libraries, Tkinter, and sockets.
1593
1594- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1595
1596Tools and other miscellany
1597
1598- Removed debugging prints from main used with freeze.
1599
Tim Peters46446d62000-10-09 21:19:31 +00001600- IDLE auto-indent no longer crashes when it encounters Unicode
1601 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001602
1603What's new in 2.0 beta 2 (since beta 1)?
1604========================================
1605
1606Core language, builtins, and interpreter
1607
Tim Peters482c0212000-09-26 06:33:09 +00001608- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001609 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001610
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001611- Add -h and -V command line options to print the usage message and
1612 Python version number and exit immediately.
1613
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001614- eval() and exec accept Unicode objects as code parameters.
1615
1616- getattr() and setattr() now also accept Unicode objects for the
1617 attribute name, which are converted to strings using the default
1618 encoding before lookup.
1619
1620- Multiplication on string and Unicode now does proper bounds
1621 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1622 string is too long."
1623
1624- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001625 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001626
Jeremy Hylton1b618592000-09-26 05:32:36 +00001627
1628Standard library and extensions
1629
Guido van Rossum5b08f132001-04-16 02:05:23 +00001630- socket module: the OpenSSL code now adds support for RAND_status()
1631 and EGD (Entropy Gathering Device).
1632
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001633- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001634 argument checking; it still takes no arguments.
1635
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001636- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001637
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001638- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001639
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001640- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001641
1642- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001643 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001644
1645- copy: Copy Unicode objects atomically.
1646
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001647- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001648
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001649- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001650
Fred Drake67233bc2000-09-26 16:40:27 +00001651- dbm: Add get() and setdefault() methods to dbm object. Add constant
1652 `library' to module that names the library used. Added doc strings
1653 and method names to error messages. Uses configure to determine
1654 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
1655 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001656
1657- distutils: Update to version 0.9.3.
1658
1659- dl: Add several dl.RTLD_ constants.
1660
1661- fpectl: Now supported on FreeBSD.
1662
1663- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
1664 found by the collector will be saved in gc.garbage. This is useful
1665 for debugging a program that creates reference cycles.
1666
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001667- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00001668 of HTTP class. Do not close socket on zero-length response. Do not
1669 crash when server sends invalid content-length header.
1670
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001671- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001672
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001673- marshal: When reading a short, sign-extend on platforms where shorts
1674 are bigger than 16 bits. When reading a long, repair the unportable
1675 sign extension that was being done for 64-bit machines. (It assumed
1676 that signed right shift sign-extends.)
1677
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001678- operator: Add contains(), invert(), __invert__() as aliases for
1679 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001680
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001681- os: Add support for popen2() and popen3() on all platforms where
1682 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001683
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001684- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00001685 clicking on a file in Explorer (or passing the file name to the
1686 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001687
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001688- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00001689 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001690
1691- pickle: Now raises ValueError when an invalid pickle that contains
1692 a non-string repr where a string repr was expected. This behavior
1693 matches cPickle.
1694
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001695- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001696
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001697- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001698
1699- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001700 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001701 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001702
1703- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001704 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001705
1706- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00001707 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00001708 few cycles during startup since the first call to
1709 setdefaultencoding() will initialize the codec registry and the
1710 encodings package.
1711
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001712- socket: Support for size hint in readlines() method of object returned
1713 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001714
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001715- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001716 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001717 is followed by whitespace.
1718
Tim Petersa3a3a032000-11-30 05:22:44 +00001719- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001720
1721- struct: Check ranges for bytes and shorts.
1722
1723- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001724 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001725
1726- Tkinter: Image objects are now guaranteed to have unique ids. Set
1727 event.delta to zero if Tk version doesn't support mousewheel.
1728 Removed some debugging prints.
1729
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001730- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001731
Fred Drake67233bc2000-09-26 16:40:27 +00001732- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001733 which works around a bug in Norton AntiVirus 2000 that leads directly
1734 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001735
1736- xml: New version detection code allows PyXML to override standard
1737 XML package if PyXML version is greater than 0.6.1.
1738
Fred Drake64bb3802000-09-26 16:21:35 +00001739- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
1740 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
1741 tree only for nodes which are sufficiently interesting to a specific
1742 application. Does not provide the HTML-specific extensions. Still
1743 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001744
Fred Drake64bb3802000-09-26 16:21:35 +00001745- xml.sax: SAX 2 support for Python, including all the handler
1746 interfaces needed to process XML 1.0 compliant XML. Some
1747 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001748
Fred Drake64bb3802000-09-26 16:21:35 +00001749- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
1750 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001751
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001752
Jeremy Hylton1b618592000-09-26 05:32:36 +00001753C API
1754
1755- Add three new convenience functions for module initialization --
1756 PyModule_AddObject(), PyModule_AddIntConstant(), and
1757 PyModule_AddStringConstant().
1758
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001759- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00001760 removed and add #error to Python.h if NULL isn't defined after
1761 #include of stdio.h.
1762
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001763- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00001764 backwards compatibility (at the source level) with old extensions.
1765
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001766- A wrapper API was added for signal() and sigaction(). Instead of
1767 either function, always use PyOS_getsig() to get a signal handler
1768 and PyOS_setsig() to set one. A new convenience typedef
1769 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001770
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001771- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00001772 internal data buffer and size of a string object -- or the default
1773 encoded version of a Unicode object.
1774
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001775- PyString_Size() and PyString_AsString() accept Unicode objects.
1776
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001777- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00001778 exists). INT_MAX and LONG_MAX will always be defined, even if
1779 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001780
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001781- PyFloat_FromString takes a second argument, pend, that was
1782 effectively useless. It is now officially useless but preserved for
1783 backwards compatibility. If the pend argument is not NULL, *pend is
1784 set to NULL.
1785
1786- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
1787 for the attribute name. See note on getattr() above.
1788
1789- A few bug fixes to argument processing for Unicode.
1790 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
1791 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
1792 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00001793 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001794
1795- Py_BuildValue accepts B format (for bgen-generated code).
1796
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001797
Jeremy Hylton1b618592000-09-26 05:32:36 +00001798Internals
1799
1800- On Unix, fix code for finding Python installation directory so that
1801 it works when argv[0] is a relative path.
1802
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00001803- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001804 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00001805 rather than by generating a copy of the object.
1806
Tim Peters482c0212000-09-26 06:33:09 +00001807- Several of the internal Unicode tables are much smaller now, and
1808 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001809
Jeremy Hylton97693b02000-09-26 17:42:51 +00001810- In the garbage collector: Fixed bug in collection of tuples. Fixed
1811 bug that caused some instances to be removed from the container set
1812 while they were still live. Fixed parsing in gc.set_debug() for
1813 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001814
1815- Fixed refcount problem in instance deallocation that only occurred
1816 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
1817
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001818- On Windows, getpythonregpath is now protected against null data in
1819 registry key.
1820
1821- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00001822 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001823
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001824
Jeremy Hylton1b618592000-09-26 05:32:36 +00001825Build and platform-specific issues
1826
1827- Better support of GNU Pth via --with-pth configure option.
1828
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001829- Python/C API now properly exposed to dynamically-loaded extension
1830 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001831
1832- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
1833 Don't define MS_SYNC to be zero when it is undefined. Added missing
1834 prototypes in posixmodule.c.
1835
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001836- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001837 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001838
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001839- Fix largefile support on older NetBSD systems and OpenBSD by adding
1840 define for TELL64.
1841
1842
1843Tools and other miscellany
1844
1845- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
1846
1847- freeze: The modulefinder now works with 2.0 opcodes.
1848
Tim Petersa3a3a032000-11-30 05:22:44 +00001849- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001850 Move hackery of sys.argv until after the Tk instance has been
1851 created, which allows the application-specific Tkinter
1852 initialization to be executed if present; also pass an explicit
1853 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00001854
Jeremy Hylton1b618592000-09-26 05:32:36 +00001855
1856What's new in 2.0 beta 1?
1857=========================
1858
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001859Source Incompatibilities
1860------------------------
1861
1862None. Note that 1.6 introduced several incompatibilities with 1.5.2,
1863such as single-argument append(), connect() and bind(), and changes to
1864str(long) and repr(float).
1865
1866
1867Binary Incompatibilities
1868------------------------
1869
1870- Third party extensions built for Python 1.5.x or 1.6 cannot be used
1871with Python 2.0; these extensions will have to be rebuilt for Python
18722.0.
1873
1874- On Windows, attempting to import a third party extension built for
1875Python 1.5.x or 1.6 results in an immediate crash; there's not much we
1876can do about this. Check your PYTHONPATH environment variable!
1877
1878- Python bytecode files (*.pyc and *.pyo) are not compatible between
1879releases.
1880
1881
1882Overview of Changes Since 1.6
1883-----------------------------
1884
1885There are many new modules (including brand new XML support through
1886the xml package, and i18n support through the gettext module); a list
1887of all new modules is included below. Lots of bugs have been fixed.
1888
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001889The process for making major new changes to the language has changed
1890since Python 1.6. Enhancements must now be documented by a Python
1891Enhancement Proposal (PEP) before they can be accepted.
1892
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001893There are several important syntax enhancements, described in more
1894detail below:
1895
1896 - Augmented assignment, e.g. x += 1
1897
1898 - List comprehensions, e.g. [x**2 for x in range(10)]
1899
1900 - Extended import statement, e.g. import Module as Name
1901
1902 - Extended print statement, e.g. print >> file, "Hello"
1903
1904Other important changes:
1905
1906 - Optional collection of cyclical garbage
1907
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001908Python Enhancement Proposal (PEP)
1909---------------------------------
1910
1911PEP stands for Python Enhancement Proposal. A PEP is a design
1912document providing information to the Python community, or describing
1913a new feature for Python. The PEP should provide a concise technical
1914specification of the feature and a rationale for the feature.
1915
1916We intend PEPs to be the primary mechanisms for proposing new
1917features, for collecting community input on an issue, and for
1918documenting the design decisions that have gone into Python. The PEP
1919author is responsible for building consensus within the community and
1920documenting dissenting opinions.
1921
1922The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001923
1924Augmented Assignment
1925--------------------
1926
1927This must have been the most-requested feature of the past years!
1928Eleven new assignment operators were added:
1929
Guido van Rossume905e952000-09-05 12:42:46 +00001930 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001931
1932For example,
1933
1934 A += B
1935
1936is similar to
1937
1938 A = A + B
1939
1940except that A is evaluated only once (relevant when A is something
1941like dict[index].attr).
1942
1943However, if A is a mutable object, A may be modified in place. Thus,
1944if A is a number or a string, A += B has the same effect as A = A+B
1945(except A is only evaluated once); but if a is a list, A += B has the
1946same effect as A.extend(B)!
1947
1948Classes and built-in object types can override the new operators in
1949order to implement the in-place behavior; the not-in-place behavior is
1950used automatically as a fallback when an object doesn't implement the
1951in-place behavior. For classes, the method name is derived from the
1952method name for the corresponding not-in-place operator by inserting
1953an 'i' in front of the name, e.g. __iadd__ implements in-place
1954__add__.
1955
1956Augmented assignment was implemented by Thomas Wouters.
1957
1958
1959List Comprehensions
1960-------------------
1961
1962This is a flexible new notation for lists whose elements are computed
1963from another list (or lists). The simplest form is:
1964
1965 [<expression> for <variable> in <sequence>]
1966
Guido van Rossum56db0952000-09-06 23:34:25 +00001967For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001968This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001969
1970You can also add a condition:
1971
1972 [<expression> for <variable> in <sequence> if <condition>]
1973
1974For example, [w for w in words if w == w.lower()] would yield the list
1975of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001976than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001977
1978You can also have nested for loops and more than one 'if' clause. For
1979example, here's a function that flattens a sequence of sequences::
1980
1981 def flatten(seq):
1982 return [x for subseq in seq for x in subseq]
1983
1984 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
1985
1986This prints
1987
1988 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
1989
1990List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001991Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001992
1993
1994Extended Import Statement
1995-------------------------
1996
1997Many people have asked for a way to import a module under a different
1998name. This can be accomplished like this:
1999
2000 import foo
2001 bar = foo
2002 del foo
2003
2004but this common idiom gets old quickly. A simple extension of the
2005import statement now allows this to be written as follows:
2006
2007 import foo as bar
2008
2009There's also a variant for 'from ... import':
2010
2011 from foo import bar as spam
2012
2013This also works with packages; e.g. you can write this:
2014
2015 import test.regrtest as regrtest
2016
2017Note that 'as' is not a new keyword -- it is recognized only in this
2018context (this is only possible because the syntax for the import
2019statement doesn't involve expressions).
2020
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002021Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002022
2023
2024Extended Print Statement
2025------------------------
2026
2027Easily the most controversial new feature, this extension to the print
2028statement adds an option to make the output go to a different file
2029than the default sys.stdout.
2030
2031For example, to write an error message to sys.stderr, you can now
2032write:
2033
2034 print >> sys.stderr, "Error: bad dog!"
2035
2036As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002037evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002038
2039 print >> None, "Hello world"
2040
2041is equivalent to
2042
2043 print "Hello world"
2044
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002045Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002046
2047
2048Optional Collection of Cyclical Garbage
2049---------------------------------------
2050
2051Python is now equipped with a garbage collector that can hunt down
2052cyclical references between Python objects. It's no replacement for
2053reference counting; in fact, it depends on the reference counts being
2054correct, and decides that a set of objects belong to a cycle if all
2055their reference counts can be accounted for from their references to
2056each other. This devious scheme was first proposed by Eric Tiedemann,
2057and brought to implementation by Neil Schemenauer.
2058
2059There's a module "gc" that lets you control some parameters of the
2060garbage collection. There's also an option to the configure script
2061that lets you enable or disable the garbage collection. In 2.0b1,
2062it's on by default, so that we (hopefully) can collect decent user
2063experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002064performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002065off by default in the final 2.0 release.
2066
2067
2068Smaller Changes
2069---------------
2070
2071A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2072map(None, seq1, seq2, ...) when the sequences have the same length;
2073i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2074the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002075zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002076
2077sys.version_info is a tuple (major, minor, micro, level, serial).
2078
2079Dictionaries have an odd new method, setdefault(key, default).
2080dict.setdefault(key, default) returns dict[key] if it exists; if not,
2081it sets dict[key] to default and returns that value. Thus:
2082
2083 dict.setdefault(key, []).append(item)
2084
2085does the same work as this common idiom:
2086
2087 if not dict.has_key(key):
2088 dict[key] = []
2089 dict[key].append(item)
2090
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002091There are two new variants of SyntaxError that are raised for
2092indentation-related errors: IndentationError and TabError.
2093
2094Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2095escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002096
2097The limits on the size of expressions and file in Python source code
2098have been raised from 2**16 to 2**32. Previous versions of Python
2099were limited because the maximum argument size the Python VM accepted
2100was 2**16. This limited the size of object constructor expressions,
2101e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2102limit was raised thanks to a patch by Charles Waldman that effectively
2103fixes the problem. It is now much more likely that you will be
2104limited by available memory than by an arbitrary limit in Python.
2105
2106The interpreter's maximum recursion depth can be modified by Python
2107programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2108limit is the maximum number of recursive calls that can be made by
2109Python code. The limit exists to prevent infinite recursion from
2110overflowing the C stack and causing a core dump. The default value is
21111000. The maximum safe value for a particular platform can be found
2112by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002113
2114New Modules and Packages
2115------------------------
2116
2117atexit - for registering functions to be called when Python exits.
2118
2119imputil - Greg Stein's alternative API for writing custom import
2120hooks.
2121
2122pyexpat - an interface to the Expat XML parser, contributed by Paul
2123Prescod.
2124
2125xml - a new package with XML support code organized (so far) in three
2126subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2127would fill a volume. There's a special feature whereby a
2128user-installed package named _xmlplus overrides the standard
2129xmlpackage; this is intended to give the XML SIG a hook to distribute
2130backwards-compatible updates to the standard xml package.
2131
2132webbrowser - a platform-independent API to launch a web browser.
2133
2134
Guido van Rossume905e952000-09-05 12:42:46 +00002135Changed Modules
2136---------------
2137
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002138array -- new methods for array objects: count, extend, index, pop, and
2139remove
2140
2141binascii -- new functions b2a_hex and a2b_hex that convert between
2142binary data and its hex representation
2143
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002144calendar -- Many new functions that support features including control
2145over which day of the week is the first day, returning strings instead
2146of printing them. Also new symbolic constants for days of week,
2147e.g. MONDAY, ..., SUNDAY.
2148
2149cgi -- FieldStorage objects have a getvalue method that works like a
2150dictionary's get method and returns the value attribute of the object.
2151
2152ConfigParser -- The parser object has new methods has_option,
2153remove_section, remove_option, set, and write. They allow the module
2154to be used for writing config files as well as reading them.
2155
2156ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002157optionally support the RFC 959 REST command.
2158
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002159gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002160
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002161httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2162the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002163
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002164locale -- implement getdefaultlocale for Win32 and Macintosh
2165
2166marshal -- no longer dumps core when marshaling deeply nested or
2167recursive data structures
2168
2169os -- new functions isatty, seteuid, setegid, setreuid, setregid
2170
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002171os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2172support under Unix.
2173
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002174os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002175
2176os.path -- fix semantics of os.path.commonprefix
2177
2178smtplib -- support for sending very long messages
2179
2180socket -- new function getfqdn()
2181
2182readline -- new functions to read, write and truncate history files.
2183The readline section of the library reference manual contains an
2184example.
2185
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002186select -- add interface to poll system call
2187
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002188shutil -- new copyfileobj function
2189
2190SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2191HTTP server.
2192
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002193Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002194
2195urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002196e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002197
2198whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002199
2200
2201Obsolete Modules
2202----------------
2203
2204None. However note that 1.6 made a whole slew of modules obsolete:
2205stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2206poly, zmod, strop, util, whatsound.
2207
2208
2209Changed, New, Obsolete Tools
2210----------------------------
2211
Tim Peters8b092332000-09-05 20:15:25 +00002212None.
Guido van Rossume905e952000-09-05 12:42:46 +00002213
2214
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002215C-level Changes
2216---------------
2217
2218Several cleanup jobs were carried out throughout the source code.
2219
2220All C code was converted to ANSI C; we got rid of all uses of the
2221Py_PROTO() macro, which makes the header files a lot more readable.
2222
2223Most of the portability hacks were moved to a new header file,
2224pyport.h; several other new header files were added and some old
2225header files were removed, in an attempt to create a more rational set
2226of header files. (Few of these ever need to be included explicitly;
2227they are all included by Python.h.)
2228
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002229Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002230and Win64, especially for the new Intel Itanium processor. Mick also
2231added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002232
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002233The C APIs to return an object's size have been update to consistently
2234use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2235previous versions, the abstract interfaces used PyXXX_Length and the
2236concrete interfaces used PyXXX_Size. The old names,
2237e.g. PyObject_Length, are still available for backwards compatibility
2238at the API level, but are deprecated.
2239
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002240The PyOS_CheckStack function has been implemented on Windows by
2241Fredrik Lundh. It prevents Python from failing with a stack overflow
2242on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002243
2244The GC changes resulted in creation of two new slots on object,
2245tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002246the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002247
2248The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002249C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002250
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002251PyErr_Format has been updated to automatically calculate the size of
2252the buffer needed to hold the formatted result string. This change
2253prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002254
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002255New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002256
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002257PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2258that are the same as their non-Ex counterparts except they take an
2259extra flag argument that tells them to close the file when done.
2260
2261XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002262
Tim Peters8b092332000-09-05 20:15:25 +00002263
2264Windows Changes
2265---------------
2266
2267New popen2/popen3/peopen4 in os module (see Changed Modules above).
2268
2269os.popen is much more usable on Windows 95 and 98. See Microsoft
2270Knowledge Base article Q150956. The Win9x workaround described there
2271is implemented by the new w9xpopen.exe helper in the root of your
2272Python installation. Note that Python uses this internally; it is not
2273a standalone program.
2274
2275Administrator privileges are no longer required to install Python
2276on Windows NT or Windows 2000. If you have administrator privileges,
2277Python's registry info will be written under HKEY_LOCAL_MACHINE.
2278Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002279under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002280uses of Python, but will prevent some advanced uses from working
2281(for example, running a Python script as an NT service, or possibly
2282from CGI).
2283
2284[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2285installer; instead, it installs the needed Tcl/Tk files directly in the
2286Python directory. If you already have a Tcl/Tk installation, this
2287wastes some disk space (about 4 Megs) but avoids problems with
2288conflicting Tcl/Tk installations, and makes it much easier for Python
2289to ensure that Tcl/Tk can find all its files.
2290
2291[This was new in 1.6] The Windows installer now installs by default in
2292\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2293
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002294
2295Updates to the changes between 1.5.2 and 1.6
2296--------------------------------------------
2297
2298The 1.6 NEWS file can't be changed after the release is done, so here
2299is some late-breaking news:
2300
2301New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2302and changes to getlocale() and setlocale().
2303
2304The new module is now enabled per default.
2305
2306It is not true that the encodings codecs cannot be used for normal
2307strings: the string.encode() (which is also present on 8-bit strings
2308!) allows using them for 8-bit strings too, e.g. to convert files from
2309cp1252 (Windows) to latin-1 or vice-versa.
2310
2311Japanese codecs are available from Tamito KAJIYAMA:
2312http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2313
2314
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002315======================================================================