blob: a1557f88d47a017e66fdd9d2469cdbde4b844678 [file] [log] [blame]
Tim Petersedc99312001-08-22 21:36:50 +00001What's New in Python 2.2a3?
2===========================
3
4Core
5
Tim Peters5d2b77c2001-09-03 05:47:38 +00006- The builtin dir() now returns more information, and sometimes much
7 more, generally naming all attributes of an object, and all attributes
8 reachable from the object via its class, and from its class's base
9 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
10 an empty list. In 2.2a3,
11
12 >>> dir([])
13 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
14 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
15 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
16 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
17 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
18 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
19 'reverse', 'sort']
20
21 dir(module) continues to return only the module's attributes, though.
22
Tim Petersbdee63f2001-09-02 03:40:59 +000023- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +000024 than raising OverflowError. This is a partial implementation of PEP
25 237. You can use -Wdefault::OverflowWarning to enable a warning for
26 this situation, and -Werror::OverflowWarning to revert to the old
27 OverflowError exception.
28
Tim Petersbdee63f2001-09-02 03:40:59 +000029- A new command line option, -D<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +000030 warnings for the use of classic division. (See PEP 238.) Possible
31 values are -Dold, -Dwarn, and -Dnew. The default is -Dold, meaning
32 the / operator has its classic meaning and no warnings are issued.
33 Using -Dwarn issues a run-time warning about all uses of classic
34 division for int, long, float and complex arguments. Using -Dnew is
35 questionable; it turns on new division by default, but only in the
36 __main__ module. You can usefully combine -Dwarn and -Dnew: this
37 gives the __main__ module new division, and warns about classic
38 division everywhere else.
39
Tim Petersbdee63f2001-09-02 03:40:59 +000040- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +000041 long, float, str, unicode, and tuple. (The types complex, list and
42 dictionary can also be subclassed; this was introduced earlier.)
43 Note that restrictions apply when subclassing immutable built-in
44 types: you can only affect the value of the instance by overloading
45 __new__. You can add mutable attributes, and the subclass instances
46 will have a __dict__ attribute, but you cannot change the "value"
47 (as implemented by the base class) of an immutable subclass instance
48 once it is created.
49
Guido van Rossumaaf80c82001-09-02 13:44:35 +000050- The dictionary constructor now takes an optional argument, a
51 mapping-like object, and initializes the dictionary from its
52 (key, value) pairs.
53
Tim Petersbdee63f2001-09-02 03:40:59 +000054- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +000055 "cooperative super calls" in a multiple inheritance setting. For an
56 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
57
Tim Petersbdee63f2001-09-02 03:40:59 +000058- A new built-in type, getset, has been added. This enables the
Guido van Rossumae457142001-08-31 18:31:35 +000059 creation of "computed attributes". Such attributes are implemented
60 by getter and setter functions (or only one of these for read-only
61 or write-only attributes), without the need to override
62 __getattr__. See http://www.python.org/2.2/descrintro.html#getset
63
Tim Petersbdee63f2001-09-02 03:40:59 +000064- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +000065 liberalized, to allow leading zeroes. Examples of literals now
66 legal that were SyntaxErrors before:
67
68 00.0 0e3 0100j 07.5 00000000000000000008.
69
Tim Petersbdee63f2001-09-02 03:40:59 +000070- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +000071 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
72
Tim Petersedc99312001-08-22 21:36:50 +000073Library
74
Tim Petersbdee63f2001-09-02 03:40:59 +000075- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +000076 currently held. See the docs for the imp module.
77
Tim Petersbdee63f2001-09-02 03:40:59 +000078- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +000079 dumps containing ints written on platforms where Python ints are 8 bytes.
80 When read on a box where Python ints are 4 bytes, such values are
81 converted to Python longs.
82
Tim Petersbdee63f2001-09-02 03:40:59 +000083- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +000084 code objects is no longer allowed. This plugs a security hole.
85
Tim Petersedc99312001-08-22 21:36:50 +000086Tools
87
88Build
89
Tim Peters69232342001-08-30 05:16:13 +000090API
91
Tim Petersbdee63f2001-09-02 03:40:59 +000092- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +000093 compile but will not participate in GC. To upgrade an extension
94 module:
95
96 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +000097
Neil Schemenauer4042c692001-08-30 15:38:01 +000098 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
99 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000100
Neil Schemenauer4042c692001-08-30 15:38:01 +0000101 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
102 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000103
Neil Schemenauer4042c692001-08-30 15:38:01 +0000104 - remove PyGC_HEAD_SIZE from object size calculations
105
106 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
107
Tim Petersbdee63f2001-09-02 03:40:59 +0000108- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000109 These can be used safely to construct string objects from a
110 sprintf-style format string (similar to the format string supported
111 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000112
Tim Petersedc99312001-08-22 21:36:50 +0000113New platforms
114
Tim Petersb7da0902001-09-02 23:01:43 +0000115- Stephen Hansen contributed patches sufficient to get a clean compile
116 under Borland C (Windows), but he reports problems running it and ran
117 out of time to complete the port. Volunteers? Expect a MemoryError
118 when importing the types module; this is probably shallow, and
119 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000120
Tim Petersedc99312001-08-22 21:36:50 +0000121Tests
122
123Windows
124
Tim Petersbdee63f2001-09-02 03:40:59 +0000125- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000126 points to command.com (patch from Brian Quinlan).
127
Tim Petersedc99312001-08-22 21:36:50 +0000128
Tim Peters20f51a72001-07-21 02:31:40 +0000129What's New in Python 2.2a2?
130===========================
131
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000132Build
133
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000134- Tim Peters developed a brand new Windows installer using Wise 8.1,
135 generously donated to us by Wise Solutions.
136
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000137- configure supports a new option --enable-unicode, with the values
138 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
139 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000140
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000141- A new configure option --enable-framework builds a Mac OS X framework,
142 which "make frameworkinstall" will install. This provides a starting
143 point for more mac-like functionality, join pythonmac-sig@python.org
144 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000145
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000146- The NeXT platform is no longer supported.
147
148- The `new' module is now statically linked.
149
Tim Peters0afb6092001-08-15 06:06:44 +0000150Tools
151
152- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000153 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000154 the module docstring for details.
155
Tim Peters20f51a72001-07-21 02:31:40 +0000156Tests
157
Tim Peters5e824c32001-08-12 22:25:01 +0000158- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000159 platforms, allowing to give clearer test result output. regrtest
160 also has optional --use/-u switch to run normally disabled tests
161 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000162
Tim Peters20f51a72001-07-21 02:31:40 +0000163- Several new tests in the standard test suite, with special thanks to
164 Nick Mathewson.
165
166Core
167
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000168- The floor division operator // has been added as outlined in PEP
169 238. The / operator still provides classic division (and will until
170 Python 3.0) unless "from __future__ import division" is included, in
171 which case the / operator will provide true division. The operator
172 module provides truediv() and floordiv() functions. Augmented
173 assignment variants are included, as are the equivalent overloadable
174 methods and C API methods. See the PEP for a full discussion:
175 <http://python.sf.net/peps/pep-0238.html>
176
Tim Peters6cd6a822001-08-17 22:11:27 +0000177- Future statements are now effective in simulated interactive shells
178 (like IDLE). This should "just work" by magic, but read Michael
179 Hudson's "Future statements in simulated shells" PEP 264 for full
180 details: <http://python.sf.net/peps/pep-0264.html>.
181
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000182- The type/class unification (PEP 252-253) was integrated into the
183 trunk and is not so tentative any more (the exact specification of
184 some features is still tentative). A lot of work has done on fixing
185 bugs and adding robustness and features (performance still has to
186 come a long way).
187
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000188- Warnings about a mismatch in the Python API during extension import
189 now use the Python warning framework (which makes it possible to
190 write filters for these warnings).
191
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000192- A function's __dict__ (aka func_dict) will now always be a
193 dictionary. It used to be possible to delete it or set it to None,
194 but now both actions raise TypeErrors. It is still legal to set it
195 to a dictionary object. Getting func.__dict__ before any attributes
196 have been assigned now returns an empty dictionary instead of None.
197
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000198Library
199
Tim Peters5e824c32001-08-12 22:25:01 +0000200- New class Differ and new functions ndiff() and restore() in difflib.py.
201 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000202 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000203
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000204- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
205 value using the minimal quoting required for the value; more
206 reliable than using xml.sax.saxutils.escape() for attribute values.
207
208- Readline completion support for cmd.Cmd was added.
209
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000210- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
211
212- Added function threading.BoundedSemaphore()
213
214- Added Ka-Ping Yee's cgitb.py module.
215
216- The `new' module now exposes the CO_xxx flags.
217
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000218New platforms
219
220C API
221
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000222- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
223 which provide a cross-platform implementations for the
224 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
225 the standard sprintf() and vsprintf() C lib APIs, these versions
226 apply bounds checking on the used buffer which enhances protection
227 against buffer overruns.
228
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000229- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000230 and extensions using different Unicode widths is rendered next to
231 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000232 will result in an ImportError. Unicode extensions writers must make
233 sure to check the Unicode width compatibility in their extensions by
234 using at least one of the mangled Unicode APIs in the extension.
235
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000236- Two new flags METH_NOARGS and METH_O are available in method definition
237 tables to simplify implementation of methods with no arguments and a
238 single untyped argument. Calling such methods is more efficient than
239 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
240 deprecated.
241
Tim Petersc1731372001-08-04 08:12:36 +0000242Windows
243
244- "import module" now compiles module.pyw if it exists and nothing else
245 relevant is found.
246
Tim Peters20f51a72001-07-21 02:31:40 +0000247
Guido van Rossum55a78992001-07-17 17:22:32 +0000248What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +0000249===========================
250
251Core
Tim Petersa814db52001-05-14 07:05:58 +0000252
Tim Peters6d6c1a32001-08-02 04:15:00 +0000253- TENTATIVELY, a large amount of code implementing much of what's
254 described in PEP 252 (Making Types Look More Like Classes) and PEP
255 253 (Subtyping Built-in Types) was added. This will be released
256 with Python 2.2a1. Documentation will be provided separately
257 through http://www.python.org/2.2/. The purpose of releasing this
258 with Python 2.2a1 is to test backwards compatibility. It is
259 possible, though not likely, that a decision is made not to release
260 this code as part of 2.2 final, if any serious backwards
261 incompapatibilities are found during alpha testing that cannot be
262 repaired.
263
Guido van Rossum55a78992001-07-17 17:22:32 +0000264- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000265 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000266 more 'yield' statements. See PEP 255. Since this adds a new
267 keyword to the language, this feature must be enabled by including a
268 future statement: "from __future__ import generators" (see PEP 236).
269 Generators will become a standard feature in a future release
270 (probably 2.3). Without this future statement, 'yield' remains an
271 ordinary identifier, but a warning is issued each time it is used.
272 (These warnings currently don't conform to the warnings framework of
273 PEP 230; we intend to fix this in 2.2a2.)
274
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000275- The UTF-16 codec was modified to be more RFC compliant. It will now
276 only remove BOM characters at the start of the string and then
277 only if running in native mode (UTF-16-LE and -BE won't remove a
278 leading BMO character).
279
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000280- Strings now have a new method .decode() to complement the already
281 existing .encode() method. These two methods provide direct access
282 to the corresponding decoders and encoders of the registered codecs.
283
284 To enhance the usability of the .encode() method, the special
285 casing of Unicode object return values was dropped (Unicode objects
286 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000287
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000288 Both methods will now return whatever the codec in charge of the
289 requested encoding returns as object, e.g. Unicode codecs will
290 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
291 will return u"äöü"). This enables codec writer to create codecs
292 for various simple to use conversions.
293
294 New codecs were added to demonstrate these new features (the .encode()
295 and .decode() columns indicate the type of the returned objects):
296
297 Name | .encode() | .decode() | Description
298 ----------------------------------------------------------------------
299 uu | string | string | UU codec (e.g. for email)
300 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000301 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000302 zlib | string | string | zlib compression
303 hex | string | string | 2-byte hex codec
304 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
305
Mark Hammond2a0af792001-05-14 03:09:36 +0000306- Some operating systems now support the concept of a default Unicode
307 encoding for file system operations. Notably, Windows supports 'mbcs'
308 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000309 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000310 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000311
312 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000313 functions that return filenames (such as os.listdir()) to return Python
314 string objects pre-encoded using the default file system encoding for
315 the platform. As this encoding is likely to be different from Python's
316 default encoding, converting this name to a Unicode object before passing
317 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000318 would attempt to use its default encoding (generally ASCII) rather than
319 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000320
Tim Petersa814db52001-05-14 07:05:58 +0000321 In general, this change simply removes surprises when working with
322 Unicode and the file system, making these operations work as you expect,
323 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000324 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000325
Tim Peters61dff2b2001-05-08 15:43:37 +0000326- Float (and complex) literals in source code were evaluated to full
327 precision only when running from a .py file; the same code loaded from a
328 .pyc (or .pyo) file could suffer numeric differences starting at about the
329 12th significant decimal digit. For example, on a machine with IEEE-754
330 floating arithmetic,
331
332 x = 9007199254740992.0
333 print long(x)
334
335 printed 9007199254740992 if run directly from .py, but 9007199254740000
336 if from a compiled (.pyc or .pyo) file. This was due to marshal using
337 str(float) instead of repr(float) when building code objects. marshal
338 now uses repr(float) instead, which should reproduce floats to full
339 machine precision (assuming the platform C float<->string I/O conversion
340 functions are of good quality).
341
342 This may cause floating-point results to change in some cases, and
343 usually for the better, but may also cause numerically unstable
344 algorithms to break.
345
Tim Peters2f228e72001-05-13 00:19:31 +0000346- The implementation of dicts suffers fewer collisions, which has speed
347 benefits. However, the order in which dict entries appear in dict.keys(),
348 dict.values() and dict.items() may differ from previous releases for a
349 given dict. Nothing is defined about this order, so no program should
350 rely on it. Nevertheless, it's easy to write test cases that rely on the
351 order by accident, typically because of printing the str() or repr() of a
352 dict to an "expected results" file. See Lib/test/test_support.py's new
353 sortdict(dict) function for a simple way to display a dict in sorted
354 order.
355
Tim Peters7a3bfc32001-06-12 01:22:22 +0000356- Many other small changes to dicts were made, resulting in faster
357 operation along the most common code paths.
358
Guido van Rossum10315822001-05-01 20:54:30 +0000359- Dictionary objects now support the "in" operator: "x in dict" means
360 the same as dict.has_key(x).
361
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000362- The update() method of dictionaries now accepts generic mapping
363 objects. Specifically the argument object must support the .keys()
364 and __getitem__() methods. This allows you to say, for example,
365 {}.update(UserDict())
366
Guido van Rossum10315822001-05-01 20:54:30 +0000367- Iterators were added; this is a generalized way of providing values
368 to a for loop. See PEP 234. There's a new built-in function iter()
369 to return an iterator. There's a new protocol to get the next value
370 from an iterator using the next() method (in Python) or the
371 tp_iternext slot (in C). There's a new protocol to get iterators
372 using the __iter__() method (in Python) or the tp_iter slot (in C).
373 Iterating (i.e. a for loop) over a dictionary generates its keys.
374 Iterating over a file generates its lines.
375
Tim Petersf553f892001-05-01 20:45:31 +0000376- The following functions were generalized to work nicely with iterator
377 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000378 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000379 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
380 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000381 join() method of strings
382 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000383 'x in y' and 'x not in y' (PySequence_Contains() in C API)
384 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000385 right-hand side of assignment statements with multiple targets, such as
386 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000387
Tim Petersd85e1022001-05-11 21:51:48 +0000388- Accessing module attributes is significantly faster (for example,
389 random.random or os.path or yourPythonModule.yourAttribute).
390
Tim Peterse63415e2001-05-08 04:38:29 +0000391- Comparing dictionary objects via == and != is faster, and now works even
392 if the keys and values don't support comparisons other than ==.
393
Tim Peters95bf9392001-05-10 08:32:44 +0000394- Comparing dictionaries in ways other than == and != is slower: there were
395 insecurities in the dict comparison implementation that could cause Python
396 to crash if the element comparison routines for the dict keys and/or
397 values mutated the dicts. Making the code bulletproof slowed it down.
398
Tim Peterseb28ef22001-06-02 05:27:19 +0000399- Collisions in dicts are resolved via a new approach, which can help
400 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000401 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000402 faster now. Thanks to Christian Tismer for pointing out the cause and
403 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000404
Tim Peters52e155e2001-06-16 05:42:57 +0000405- repr() is much faster for large containers (dict, list, tuple).
406
407
Tim Petersa814db52001-05-14 07:05:58 +0000408Library
409
Fred Drake960fdf92001-07-20 18:38:26 +0000410- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
411 were added to the string module. These a locale-indenpendent
412 constants, unlike letters, lowercase, and uppercase. These are now
413 use in appropriate locations in the standard library.
414
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000415- The flags used in dlopen calls can now be configured using
416 sys.setdlopenflags and queried using sys.getdlopenflags.
417
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000418- Fredrik Lundh's xmlrpclib is now a standard library module. This
419 provides full client-side XML-RPC support. In addition,
420 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
421 one asyncore-based). Thanks to Eric Raymond for the documentation.
422
Guido van Rossum643d3912001-07-05 14:46:25 +0000423- The xrange() object is simplified: it no longer supports slicing,
424 repetition, comparisons, efficient 'in' checking, the tolist()
425 method, or the start, stop and step attributes. See PEP 260.
426
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000427- A new function fnmatch.filter to filter lists of file names was added.
428
Barry Warsawffd674d2001-05-22 16:00:10 +0000429- calendar.py uses month and day names based on the current locale.
430
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000431- strop is now *really* obsolete (this was announced before with 1.6),
432 and issues DeprecationWarning when used (except for the four items
433 that are still imported into string.py).
434
Tim Petersa814db52001-05-14 07:05:58 +0000435- Cookie.py now sorts key+value pairs by key in output strings.
436
437- pprint.isrecursive(object) didn't correctly identify recursive objects.
438 Now it does.
439
Tim Peters95b3f782001-05-14 18:39:41 +0000440- pprint functions now much faster for large containers (tuple, list, dict).
441
Tim Peters7b9542a2001-06-10 23:40:19 +0000442- New 'q' and 'Q' format codes in the struct module, corresponding to C
443 types "long long" and "unsigned long long" (on Windows, __int64). In
444 native mode, these can be used only when the platform C compiler supports
445 these types (when HAVE_LONG_LONG is #define'd by the Python config
446 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000447 In standard mode, 'q' and 'Q' are supported on all platforms, and are
448 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000449
Guido van Rossum83213cc2001-06-12 16:48:52 +0000450- The site module installs a new built-in function 'help' that invokes
451 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
452 it displays a message reminding the user to use 'help()' or
453 'help(object)'.
454
Tim Petersa814db52001-05-14 07:05:58 +0000455Tests
456
457- New test_mutants.py runs dict comparisons where the key and value
458 comparison operators mutute the dicts randomly during comparison. This
459 rapidly causes Python to crash under earlier releases (not for the faint
460 of heart: it can also cause Win9x to freeze or reboot!).
461
462- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000463 pprint.isreadable() return sensible results. Also verifies that simple
464 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000465
Tim Peters4324aa32001-05-28 22:30:08 +0000466C API
467
468- Removed the unused last_is_sticky argument from the internal
469 _PyTuple_Resize(). If this affects you, you were cheating.
470
471
Guido van Rossum55a78992001-07-17 17:22:32 +0000472======================================================================
473
474
Guido van Rossumffe13be2001-04-16 18:46:45 +0000475What's New in Python 2.1 (final)?
476=================================
477
478We only changed a few things since the last release candidate, all in
479Python library code:
480
481- A bug in the locale module was fixed that affected locales which
482 define no grouping for numeric formatting.
483
484- A few bugs in the weakref module's implementations of weak
485 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
486 and the test suite was updated to check for these bugs.
487
488- An old bug in the os.path.walk() function (introduced in Python
489 2.0!) was fixed: a non-existent file would cause an exception
490 instead of being ignored.
491
492- Fixed a few bugs in the new symtable module found by Neil Norwitz's
493 PyChecker.
494
495
Guido van Rossum5b08f132001-04-16 02:05:23 +0000496What's New in Python 2.1c2?
497===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000498
Guido van Rossum5b08f132001-04-16 02:05:23 +0000499A flurry of small changes, and one showstopper fixed in the nick of
500time made it necessary to release another release candidate. The list
501here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000502
Guido van Rossum5b08f132001-04-16 02:05:23 +0000503Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000504
Guido van Rossum5b08f132001-04-16 02:05:23 +0000505- Tim discovered a nasty bug in the dictionary code, caused by
506 PyDict_Next() calling dict_resize(), and the GC code's use of
507 PyDict_Next() violating an assumption in dict_items(). This was
508 fixed with considerable amounts of band-aid, but the net effect is a
509 saner and more robust implementation.
510
511- Made a bunch of symbols static that were accidentally global.
512
513Build and Ports
514
515- The setup.py script didn't check for a new enough version of zlib
516 (1.1.3 is needed). Now it does.
517
518- Changed "make clean" target to also remove shared libraries.
519
520- Added a more general warning about the SGI Irix optimizer to README.
521
522Library
523
524- Fix a bug in urllib.basejoin("http://host", "../file.html") which
525 omitted the slash between host and file.html.
526
527- The mailbox module's _Mailbox class contained a completely broken
528 and undocumented seek() method. Ripped it out.
529
530- Fixed a bunch of typos in various library modules (urllib2, smtpd,
531 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
532
533- Fixed a few last-minute bugs in unittest.
534
535Extensions
536
537- Reverted the patch to the OpenSSL code in socketmodule.c to support
538 RAND_status() and the EGD, and the subsequent patch that tried to
539 fix it for pre-0.9.5 versions; the problem with the patch is that on
540 some systems it issues a warning whenever socket is imported, and
541 that's unacceptable.
542
543Tests
544
545- Fixed the pickle tests to work with "import test.test_pickle".
546
547- Tweaked test_locale.py to actually run the test Windows.
548
549- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
550 not "wb" (which is not a valid mode at all).
551
552- Fix pstats browser crashes. Import readline if it exists to make
553 the user interface nicer.
554
555- Add "import thread" to the top of test modules that import the
556 threading module (test_asynchat and test_threadedtempfile). This
557 prevents test failures caused by a broken threading module resulting
558 from a previously caught failed import.
559
560- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
561 needed on some platforms (e.g. Solaris 8) when the tests are run
562 twice in succession.
563
564- Skip rather than fail test_sunaudiodev if no audio device is found.
565
566
567What's New in Python 2.1c1?
568===========================
569
570This list was significantly updated when 2.1c2 was released; the 2.1c1
571release didn't mention most changes that were actually part of 2.1c1:
572
573Legal
574
575- Copyright was assigned to the Python Software Foundation (PSF) and a
576 PSF license (very similar to the CNRI license) was added.
577
578- The CNRI copyright notice was updated to include 2001.
579
580Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000581
Guido van Rossumc9932722001-04-12 02:31:27 +0000582- After a public outcry, assignment to __debug__ is no longer illegal;
583 instead, a warning is issued. It will become illegal in 2.2.
584
Guido van Rossum5b08f132001-04-16 02:05:23 +0000585- Fixed a core dump with "%#x" % 0, and changed the semantics so that
586 "%#x" now always prepends "0x", even if the value is zero.
587
588- Fixed some nits in the bytecode compiler.
589
590- Fixed core dumps when calling certain kinds of non-functions.
591
592- Fixed various core dumps caused by reference count bugs.
593
594Build and Ports
595
596- Use INSTALL_SCRIPT to install script files.
597
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000598- New port: SCO Unixware 7, by Billy G. Allie.
599
Guido van Rossum5b08f132001-04-16 02:05:23 +0000600- Updated RISCOS port.
601
602- Updated BeOS port and notes.
603
604- Various other porting problems resolved.
605
606Library
607
608- The TERMIOS and SOCKET modules are now truly obsolete and
609 unnecessary. Their symbols are incorporated in the termios and
610 socket modules.
611
612- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
613 better tests for pickling.
614
615- threading: make Condition.wait() robust against KeyboardInterrupt.
616
617- zipfile: add support to zipfile to support opening an archive
618 represented by an open file rather than a file name. Fix bug where
619 the archive was not properly closed. Fixed a bug in this bugfix
620 where flush() was called for a read-only file.
621
622- imputil: added an uninstall() method to the ImportManager.
623
624- Canvas: fixed bugs in lower() and tkraise() methods.
625
626- SocketServer: API change (added overridable close_request() method)
627 so that the TCP server can explicitly close the request.
628
629- pstats: Eric Raymond added a simple interactive statistics browser,
630 invoked when the module is run as a script.
631
632- locale: fixed a problem in format().
633
634- webbrowser: made it work when the BROWSER environment variable has a
635 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
636 KDE 2. Fixed some other nits.
637
638- unittest: changes to allow using a different exception than
639 AssertionError, and added a few more function aliases. Some other
640 small changes.
641
642- urllib, urllib2: fixed redirect problems and a coupleof other nits.
643
644- asynchat: fixed a critical bug in asynchat that slipped through the
645 2.1b2 release. Fixed another rare bug.
646
647- Fix some unqualified except: clauses (always a bad code example).
648
649XML
650
651- pyexpat: new API get_version_string().
652
653- Fixed some minidom bugs.
654
655Extensions
656
657- Fixed a core dump in _weakref. Removed the weakref.mapping()
658 function (it adds nothing to the API).
659
660- Rationalized the use of header files in the readline module, to make
661 it compile (albeit with some warnings) with the very recent readline
662 4.2, without breaking for earlier versions.
663
664- Hopefully fixed a buffering problem in linuxaudiodev.
665
666- Attempted a fix to make the OpenSSL support in the socket module
667 work again with pre-0.9.5 versions of OpenSSL.
668
669Tests
670
671- Added a test case for asynchat and asyncore.
672
673- Removed coupling between tests where one test failing could break
674 another.
675
676Tools
677
678- Ping added an interactive help browser to pydoc, fixed some nits
679 in the rest of the pydoc code, and added some features to his
680 inspect module.
681
682- An updated python-mode.el version 4.1 which integrates Ken
683 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
684 much nicer in XEmacs and Emacs. When stepping through your program
685 with pdb, in either the shell window or the *Python* window, the
686 source file and line will be tracked by an arrow. Very cool!
687
688- IDLE: syntax warnings in interactive mode are changed into errors.
689
690- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +0000691 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +0000692
693- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000694
Barry Warsaw11e89c72001-04-11 20:37:57 +0000695
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000696What's New in Python 2.1 beta 2?
697================================
698
Guido van Rossum053ae352001-03-22 14:17:21 +0000699(Unlisted are many fixed bugs, more documentation, etc.)
700
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000701Core language, builtins, and interpreter
702
Guido van Rossum053ae352001-03-22 14:17:21 +0000703- The nested scopes work (enabled by "from __future__ import
704 nested_scopes") is completed; in particular, the future now extends
705 into code executed through exec, eval() and execfile(), and into the
706 interactive interpreter.
707
708- When calling a base class method (e.g. BaseClass.__init__(self)),
709 this is now allowed even if self is not strictly spoken a class
710 instance (e.g. when using metaclasses or the Don Beaudry hook).
711
712- Slice objects are now comparable but not hashable; this prevents
713 dict[:] from being accepted but meaningless.
714
715- Complex division is now calculated using less braindead algorithms.
716 This doesn't change semantics except it's more likely to give useful
717 results in extreme cases. Complex repr() now uses full precision
718 like float repr().
719
720- sgmllib.py now calls handle_decl() for simple <!...> declarations.
721
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000722- It is illegal to assign to the name __debug__, which is set when the
723 interpreter starts. It is effectively a compile-time constant.
724
725- A warning will be issued if a global statement for a variable
726 follows a use or assignment of that variable.
727
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000728Standard library
729
Guido van Rossum053ae352001-03-22 14:17:21 +0000730- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
731 inspired by JUnit), is now part of the standard library. You now
732 have a choice of two testing frameworks: unittest requires you to
733 write testcases as separate code, doctest gathers them from
734 docstrings. Both approaches have their advantages and
735 disadvantages.
736
737- A new module Tix was added, which wraps the Tix extension library
738 for Tk. With that module, it is not necessary to statically link
739 Tix with _tkinter, since Tix will be loaded with Tcl's "package
740 require" command. See Demo/tix/.
741
742- tzparse.py is now obsolete.
743
744- In gzip.py, the seek() and tell() methods are removed -- they were
745 non-functional anyway, and it's better if callers can test for their
746 existence with hasattr().
747
748Python/C API
749
750- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
751 that's already in the dictionary during a PyDict_Next() iteration.
752 This used to fail occasionally when a dictionary resize operation
753 could be triggered that would rehash all the keys. All other
754 modifications to the dictionary are still off-limits during a
755 PyDict_Next() iteration!
756
757- New extended APIs related to passing compiler variables around.
758
759- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
760 implement isinstance() and issubclass().
761
762- Py_BuildValue() now has a "D" conversion to create a Python complex
763 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000764
Fred Drake4e262a92001-03-22 18:26:47 +0000765- Extensions types which support weak references must now set the
766 field allocated for the weak reference machinery to NULL themselves;
767 this is done to avoid the cost of checking each object for having a
768 weakly referencable type in PyObject_INIT(), since most types are
769 not weakly referencable.
770
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000771- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
772 free variables and cell variables to and from the frame's f_locals.
773
774- Variants of several functions defined in pythonrun.h have been added
775 to support the nested_scopes future statement. The variants all end
776 in Flags and take an extra argument, a PyCompilerFlags *; examples:
777 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
778 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +0000779 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000780
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000781Distutils
782
783- the sdist command now writes a PKG-INFO file, as described in PEP 241,
784 into the release tree.
785
Tim Peters0e57abf2001-05-02 07:39:38 +0000786- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000787 (an uninstaller, more customization of the installer's display)
788
789- from Jack Jansen: added Mac-specific code to generate a dialog for
790 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +0000791 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000792 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +0000793
794- added 'platforms' and 'keywords' to the set of metadata that can be
795 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000796
797- applied patches from Jason Tishler to make the compiler class work with
798 Cygwin.
799
800
Tim Peters2fe289a2001-03-01 22:19:38 +0000801What's New in Python 2.1 beta 1?
802================================
Tim Petersd66595f2001-02-04 03:09:53 +0000803
804Core language, builtins, and interpreter
805
Guido van Rossum9d0fbde2001-03-02 14:00:32 +0000806- Following an outcry from the community about the amount of code
807 broken by the nested scopes feature introduced in 2.1a2, we decided
808 to make this feature optional, and to wait until Python 2.2 (or at
809 least 6 months) to make it standard. The option can be enabled on a
810 per-module basis by adding "from __future__ import nested_scopes" at
811 the beginning of a module (before any other statements, but after
812 comments and an optional docstring). See PEP 236 (Back to the
813 __future__) for a description of the __future__ statement. PEP 227
814 (Statically Nested Scopes) has been updated to reflect this change,
815 and to clarify the semantics in a number of endcases.
816
817- The nested scopes code, when enabled, has been hardened, and most
818 bugs and memory leaks in it have been fixed.
819
820- Compile-time warnings are now generated for a number of conditions
821 that will break or change in meaning when nested scopes are enabled:
822
823 - Using "from...import *" or "exec" without in-clause in a function
824 scope that also defines a lambda or nested function with one or
825 more free (non-local) variables. The presence of the import* or
826 bare exec makes it impossible for the compiler to determine the
827 exact set of local variables in the outer scope, which makes it
828 impossible to determine the bindings for free variables in the
829 inner scope. To avoid the warning about import *, change it into
830 an import of explicitly name object, or move the import* statement
831 to the global scope; to avoid the warning about bare exec, use
832 exec...in... (a good idea anyway -- there's a possibility that
833 bare exec will be deprecated in the future).
834
835 - Use of a global variable in a nested scope with the same name as a
836 local variable in a surrounding scope. This will change in
837 meaning with nested scopes: the name in the inner scope will
838 reference the variable in the outer scope rather than the global
839 of the same name. To avoid the warning, either rename the outer
840 variable, or use a global statement in the inner function.
841
Neil Schemenauera35c6882001-02-27 04:45:05 +0000842- An optional object allocator has been included. This allocator is
843 optimized for Python objects and should be faster and use less memory
844 than the standard system allocator. It is not enabled by default
845 because of possible thread safety problems. The allocator is only
846 protected by the Python interpreter lock and it is possible that some
847 extension modules require a thread safe allocator. The object
848 allocator can be enabled by providing the "--with-pymalloc" option to
849 configure.
850
Tim Petersd66595f2001-02-04 03:09:53 +0000851Standard library
852
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000853- pyexpat now detects the expat version if expat.h defines it. A
854 number of additional handlers are provided, which are only available
855 since expat 1.95. In addition, the methods SetParamEntityParsing and
856 GetInputContext of Parser objects are available with 1.95.x
857 only. Parser objects now provide the ordered_attributes and
858 specified_attributes attributes. A new module expat.model was added,
859 which offers a number of additional constants if 1.95.x is used.
860
861- xml.dom offers the new functions registerDOMImplementation and
862 getDOMImplementation.
863
864- xml.dom.minidom offers a toprettyxml method. A number of DOM
865 conformance issues have been resolved. In particular, Element now
866 has an hasAttributes method, and the handling of namespaces was
867 improved.
868
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000869- Ka-Ping Yee contributed two new modules: inspect.py, a module for
870 getting information about live Python code, and pydoc.py, a module
871 for interactively converting docstrings to HTML or text.
872 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +0000873 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +0000874 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
875 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000876
Tim Peters1eff7962001-03-01 02:31:33 +0000877- New library module difflib.py, primarily packaging the SequenceMatcher
878 class at the heart of the popular ndiff.py file-comparison tool.
879
880- doctest.py (a framework for verifying Python code examples in docstrings)
881 is now part of the std library.
882
Tim Petersd66595f2001-02-04 03:09:53 +0000883Windows changes
884
Guido van Rossume3955a82001-03-02 14:05:59 +0000885- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
886 small GUI that lets you browse the module docstrings using your
887 default web browser.
888
Tim Peters1eff7962001-03-01 02:31:33 +0000889- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
890 Platforms) is implemented. See
891
892 http://python.sourceforge.net/peps/pep-0235.html
893
894 for full details, especially the "Current Lower-Left Semantics" section.
895 The new Windows import rules are simpler than before:
896
897 A. If the PYTHONCASEOK environment variable exists, same as
898 before: silently accept the first case-insensitive match of any
899 kind; raise ImportError if none found.
900
901 B. Else search sys.path for the first case-sensitive match; raise
902 ImportError if none found.
903
904 The same rules have been implented on other platforms with case-
905 insensitive but case-preserving filesystems too (including Cygwin, and
906 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +0000907
Tim Peters25a9ce32001-02-19 07:06:36 +0000908- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
909 what it's supposed to do (and does do under NT and 2000) via direct
910 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +0000911 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +0000912 all Win9x systems before.
913
Tim Peters1eff7962001-03-01 02:31:33 +0000914- Build: Subproject _test (effectively) renamed to _testcapi.
915
Tim Peters2fe289a2001-03-01 22:19:38 +0000916New platforms
917
918- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
919 Thanks to Steven Majewski!
920
921- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
922 Tishler!
923
Guido van Rossum9089b272001-03-02 06:49:50 +0000924- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
925 Schwertberger! See RISCOS/README for more information -- it seems
926 that because of the bizarre filename conventions on RISCOS, no port
927 to that platform is easy. Note that the new variable os.endsep is
928 silently supported in order to make life easier on this platform,
929 but we don't advertise it because it's not worth for most folks to
930 care about RISCOS portability.
931
Tim Peters25a9ce32001-02-19 07:06:36 +0000932
Tim Petersd7b5e882001-01-25 03:36:26 +0000933What's New in Python 2.1 alpha 2?
934=================================
Tim Peters40ead762001-01-27 05:35:26 +0000935
Tim Petersd7b5e882001-01-25 03:36:26 +0000936Core language, builtins, and interpreter
937
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000938- Scopes nest. If a name is used in a function or class, but is not
939 local, the definition in the nearest enclosing function scope will
940 be used. One consequence of this change is that lambda statements
941 could reference variables in the namespaces where the lambda is
942 defined. In some unusual cases, this change will break code.
943
944 In all previous version of Python, names were resolved in exactly
945 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000946 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000947 function A is defined within a function B, the names bound in B are
948 not visible in A. The new rules make names bound in B visible in A,
949 unless A contains a name binding that hides the binding in B.
950
951 Section 4.1 of the reference manual describes the new scoping rules
952 in detail. The test script in Lib/test/test_scope.py demonstrates
953 some of the effects of the change.
954
955 The new rules will cause existing code to break if it defines nested
956 functions where an outer function has local variables with the same
957 name as globals or builtins used by the inner function. Example:
958
959 def munge(str):
960 def helper(x):
961 return str(x)
962 if type(str) != type(''):
963 str = helper(str)
964 return str.strip()
965
966 Under the old rules, the name str in helper() is bound to the
967 builtin function str(). Under the new rules, it will be bound to
968 the argument named str and an error will occur when helper() is
969 called.
970
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000971- The compiler will report a SyntaxError if "from ... import *" occurs
972 in a function or class scope. The language reference has documented
973 that this case is illegal, but the compiler never checked for it.
974 The recent introduction of nested scope makes the meaning of this
975 form of name binding ambiguous. In a future release, the compiler
976 may allow this form when there is no possibility of ambiguity.
977
Tim Peters40ead762001-01-27 05:35:26 +0000978- repr(string) is easier to read, now using hex escapes instead of octal,
979 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
980
981 >>> "\texample \r\n" + chr(0) + chr(255)
982 '\texample \r\n\x00\xff' # in 2.1
983 '\011example \015\012\000\377' # in 2.0
984
Moshe Zadka6af0ce02001-01-29 06:41:00 +0000985- Functions are now compared and hashed by identity, not by value, since
986 the func_code attribute is writable.
987
Fred Drakefb9d7122001-02-01 20:00:40 +0000988- Weak references (PEP 205) have been added. This involves a few
989 changes in the core, an extension module (_weakref), and a Python
990 module (weakref). The weakref module is the public interface. It
991 includes support for "explicit" weak references, proxy objects, and
992 mappings with weakly held values.
993
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000994- A 'continue' statement can now appear in a try block within the body
995 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +0000996 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000997
Tim Petersd7b5e882001-01-25 03:36:26 +0000998Standard library
999
Barry Warsaw30dbd142001-01-31 22:14:01 +00001000- mailbox.py now has a new class, PortableUnixMailbox which is
1001 identical to UnixMailbox but uses a more portable scheme for
1002 determining From_ separators. Also, the constructors for all the
1003 classes in this module have a new optional `factory' argument, which
1004 is a callable used when new message classes must be instantiated by
1005 the next() method.
1006
Tim Petersd7b5e882001-01-25 03:36:26 +00001007- random.py is now self-contained, and offers all the functionality of
1008 the now-deprecated whrandom.py. See the docs for details. random.py
1009 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001010 and restoring the internal state of the generator; and jumpahead(n),
1011 for quickly forcing the internal state to be the same as if n calls to
1012 random() had been made. The latter is particularly useful for multi-
1013 threaded programs, creating one instance of the random.Random() class for
1014 each thread, then using .jumpahead() to force each instance to use a
1015 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001016
Tim Peters0de88fc2001-02-01 04:59:18 +00001017- random.py's seed() function is new. For bit-for-bit compatibility with
1018 prior releases, use the whseed function instead. The new seed function
1019 addresses two problems: (1) The old function couldn't produce more than
1020 about 2**24 distinct internal states; the new one about 2**45 (the best
1021 that can be done in the Wichmann-Hill generator). (2) The old function
1022 sometimes produced identical internal states when passed distinct
1023 integers, and there was no simple way to predict when that would happen;
1024 the new one guarantees to produce distinct internal states for all
1025 arguments in [0, 27814431486576L).
1026
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001027- The socket module now supports raw packets on Linux. The socket
1028 family is AF_PACKET.
1029
Tim Peters9ea17ac2001-02-02 05:57:15 +00001030- test_capi.py is a start at running tests of the Python C API. The tests
1031 are implemented by the new Modules/_testmodule.c.
1032
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001033- A new extension module, _symtable, provides provisional access to the
1034 internal symbol table used by the Python compiler. A higher-level
1035 interface will be added on top of _symtable in a future release.
1036
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001037- Removed the obsolete soundex module.
1038
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001039- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1040 the isSameNode method; NamedNodeMap the get method.
1041
1042- xml.sax.expatreader supports the lexical handler property; it
1043 generates comment, startCDATA, and endCDATA events.
1044
Tim Petersee826f82001-01-31 19:39:44 +00001045Windows changes
1046
1047- Build procedure: the zlib project is built in a different way that
1048 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001049 the zlib binary used. See PCbuild\readme.txt for details. Your old
1050 zlib-related directories can be deleted; you'll need to download fresh
1051 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001052
Tim Peters9ea17ac2001-02-02 05:57:15 +00001053- Build: New subproject _test for the benefit of test_capi.py (see above).
1054
Tim Petersb16c56f2001-02-02 21:24:51 +00001055- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1056 interface to some Python compiler internals).
1057
1058- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001059 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001060
Tim Petersa3a3a032000-11-30 05:22:44 +00001061What's New in Python 2.1 alpha 1?
1062=================================
1063
1064Core language, builtins, and interpreter
1065
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001066- There is a new Unicode companion to the PyObject_Str() API
1067 called PyObject_Unicode(). It behaves in the same way as the
1068 former, but assures that the returned value is an Unicode object
1069 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001070
Guido van Rossumf98eda02001-01-17 15:54:45 +00001071- The comparison operators support "rich comparison overloading" (PEP
1072 207). C extension types can provide a rich comparison function in
1073 the new tp_richcompare slot in the type object. The cmp() function
1074 and the C function PyObject_Compare() first try the new rich
1075 comparison operators before trying the old 3-way comparison. There
1076 is also a new C API PyObject_RichCompare() (which also falls back on
1077 the old 3-way comparison, but does not constrain the outcome of the
1078 rich comparison to a Boolean result).
1079
1080 The rich comparison function takes two objects (at least one of
1081 which is guaranteed to have the type that provided the function) and
1082 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1083 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1084 object, which may be NotImplemented (in which case the tp_compare
1085 slot function is used as a fallback, if defined).
1086
1087 Classes can overload individual comparison operators by defining one
1088 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001089 __ge__. There are no explicit "reflected argument" versions of
1090 these; instead, __lt__ and __gt__ are each other's reflection,
1091 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1092 reflection (similar at the C level). No other implications are
1093 made; in particular, Python does not assume that == is the Boolean
1094 inverse of !=, or that < is the Boolean inverse of >=. This makes
1095 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001096
1097 Classes or types that want to implement (in)equality tests but not
1098 the ordering operators (i.e. unordered types) should implement ==
1099 and !=, and raise an error for the ordering operators.
1100
Guido van Rossuma88479f2001-01-18 14:28:08 +00001101 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001102 Boolean; e.g. a matrix type might want to return a matrix of bits
1103 for A < B, giving elementwise comparisons. Such types should ensure
1104 that any interpretation of their value in a Boolean context raises
1105 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1106 at the C level) to always raise an exception.
1107
Guido van Rossuma88479f2001-01-18 14:28:08 +00001108- Complex numbers use rich comparisons to define == and != but raise
1109 an exception for <, <=, > and >=. Unfortunately, this also means
1110 that cmp() of two complex numbers raises an exception when the two
1111 numbers differ. Since it is not mathematically meaningful to compare
1112 complex numbers except for equality, I hope that this doesn't break
1113 too much code.
1114
Tim Peters3389f192001-02-18 08:48:49 +00001115- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001116 not defined by the language, other than that it's arbitrary but
1117 consistent (see the Reference Manual). An implementation detail changed
1118 in 2.1a1 such that None now compares less than any other object. Code
1119 relying on this new behavior (like code that relied on the previous
1120 behavior) does so at its own risk.
1121
Barry Warsaw573b5412001-01-15 20:43:18 +00001122- Functions and methods now support getting and setting arbitrarily
1123 named attributes (PEP 232). Functions have a new __dict__
1124 (a.k.a. func_dict) which hold the function attributes. Methods get
1125 and set attributes on their underlying im_func. It is a TypeError
1126 to set an attribute on a bound method.
1127
Guido van Rossum051e3352001-01-15 19:11:10 +00001128- The xrange() object implementation has been improved so that
1129 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1130 limitation that in this case len(xrange(sys.maxint)) can't be
1131 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1132 work fine as long as the index i doesn't actually reach 2**31.
1133 (Python uses regular ints for sequence and string indices; fixing
1134 that is much more work.)
1135
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001136- Two changes to from...import:
1137
Guido van Rossumba381232001-02-03 15:06:40 +00001138 1) "from M import X" now works even if (after loading module M)
1139 sys.modules['M'] is not a real module; it's basically a getattr()
1140 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001141
1142 2) "from M import *" now looks for M.__all__ to decide which names to
1143 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1144 filters out names starting with '_' as before. Whether or not
1145 __all__ exists, there's no restriction on the type of M.
1146
Guido van Rossumf61f1662001-01-10 20:13:55 +00001147- File objects have a new method, xreadlines(). This is the fastest
1148 way to iterate over all lines in a file:
1149
1150 for line in file.xreadlines():
1151 ...do something to line...
1152
1153 See the xreadlines module (mentioned below) for how to do this for
1154 other file-like objects.
1155
1156- Even if you don't use file.xreadlines(), you may expect a speedup on
1157 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001158 quite a bit in platform-specific ways: on systems (like Linux) that
1159 support flockfile(), getc_unlocked(), and funlockfile(), those are
1160 used by default. On systems (like Windows) without getc_unlocked(),
1161 a complicated (but still thread-safe) method using fgets() is used by
1162 default.
1163
Tim Petersd52269b2001-01-25 06:23:18 +00001164 You can force use of the fgets() method by #define'ing
1165 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001166 getc_unlocked()).
1167
Tim Petersd52269b2001-01-25 06:23:18 +00001168 You can force fgets() not to be used by #define'ing
1169 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001170 test_bufio.py fails -- and let us know if it does!).
1171
1172- In addition, the fileinput module, while still slower than the other
1173 methods on most platforms, has been sped up too, by using
1174 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001175
1176- Support for run-time warnings has been added, including a new
1177 command line option (-W) to specify the disposition of warnings.
1178 See the description of the warnings module below.
1179
1180- Extensive changes have been made to the coercion code. This mostly
1181 affects extension modules (which can now implement mixed-type
1182 numerical operators without having to use coercion), but
1183 occasionally, in boundary cases the coercion semantics have changed
1184 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001185 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001186 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001187 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001188
Guido van Rossumf98eda02001-01-17 15:54:45 +00001189- In connection with the coercion changes, a new built-in singleton
1190 object, NotImplemented is defined. This can be returned for
1191 operations that wish to indicate they are not implemented for a
1192 particular combination of arguments. From C, this is
1193 Py_NotImplemented.
1194
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001195- The interpreter accepts now bytecode files on the command line even
1196 if they do not have a .pyc or .pyo extension. On Linux, after executing
1197
Martin v. Löwise214baa2001-02-04 22:37:56 +00001198import imp,sys,string
1199magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1200reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1201open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001202
1203 any byte code file can be used as an executable (i.e. as an argument
1204 to execve(2)).
1205
Tim Peters9940b802000-12-01 07:59:35 +00001206- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001207 character. In 1.6 and earlier, they never produced a sign,
1208 and raised an error if the value of the long was too large
1209 to fit in a Python int. In 2.0, they produced a sign if and
1210 only if too large to fit in an int. This was inconsistent
1211 across platforms (because the size of an int varies across
1212 platforms), and inconsistent with hex() and oct(). Example:
1213
1214 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001215 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001216 'ffffffbe' # in 2.0 and before, on 32-bit machines
1217 >>> hex(-0x42L)
1218 '-0x42L' # in all versions of Python
1219
Tim Peters9940b802000-12-01 07:59:35 +00001220 The behavior of %d formats for negative Python longs remains
1221 the same as in 2.0 (although in 1.6 and before, they raised
1222 an error if the long didn't fit in a Python int).
1223
1224 %u formats don't make sense for Python longs, but are allowed
1225 and treated the same as %d in 2.1. In 2.0, a negative long
1226 formatted via %u produced a sign if and only if too large to
1227 fit in an int. In 1.6 and earlier, a negative long formatted
1228 via %u raised an error if it was too big to fit in an int.
1229
Guido van Rossum3661d392000-12-12 22:10:31 +00001230- Dictionary objects have an odd new method, popitem(). This removes
1231 an arbitrary item from the dictionary and returns it (in the form of
1232 a (key, value) pair). This can be useful for algorithms that use a
1233 dictionary as a bag of "to do" items and repeatedly need to pick one
1234 item. Such algorithms normally end up running in quadratic time;
1235 using popitem() they can usually be made to run in linear time.
1236
Tim Peters36cdad12000-12-29 02:06:45 +00001237Standard library
1238
Thomas Woutersfe385252001-01-19 23:16:56 +00001239- In the time module, the time argument to the functions strftime,
1240 localtime, gmtime, asctime and ctime is now optional, defaulting to
1241 the current time (in the local timezone).
1242
Guido van Rossumda91f222001-01-15 16:36:08 +00001243- The ftplib module now defaults to passive mode, which is deemed a
1244 more useful default given that clients are often inside firewalls
1245 these days. Note that this could break if ftplib is used to connect
1246 to a *server* that is inside a firewall, from outside; this is
1247 expected to be a very rare situation. To fix that, you can call
1248 ftp.set_pasv(0).
1249
Martin v. Löwis10a27872001-01-13 09:54:41 +00001250- The module site now treats .pth files not only for path configuration,
1251 but also supports extensions to the initialization code: Lines starting
1252 with import are executed.
1253
Guido van Rossumf61f1662001-01-10 20:13:55 +00001254- There's a new module, warnings, which implements a mechanism for
1255 issuing and filtering warnings. There are some new built-in
1256 exceptions that serve as warning categories, and a new command line
1257 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1258 turns warnings into errors). warnings.warn(message[, category])
1259 issues a warning message; this can also be called from C as
1260 PyErr_Warn(category, message).
1261
1262- A new module xreadlines was added. This exports a single factory
1263 function, xreadlines(). The intention is that this code is the
1264 absolutely fastest way to iterate over all lines in an open
1265 file(-like) object:
1266
1267 import xreadlines
1268 for line in xreadlines.xreadlines(file):
1269 ...do something to line...
1270
1271 This is equivalent to the previous the speed record holder using
1272 file.readlines(sizehint). Note that if file is a real file object
1273 (as opposed to a file-like object), this is equivalent:
1274
1275 for line in file.xreadlines():
1276 ...do something to line...
1277
Tim Peters36cdad12000-12-29 02:06:45 +00001278- The bisect module has new functions bisect_left, insort_left,
1279 bisect_right and insort_right. The old names bisect and insort
1280 are now aliases for bisect_right and insort_right. XXX_right
1281 and XXX_left methods differ in what happens when the new element
1282 compares equal to one or more elements already in the list: the
1283 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001284 right. Code that doesn't care where equal elements end up should
1285 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001286
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001287- The new curses.panel module wraps the panel library that forms part
1288 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1289
Guido van Rossumf61f1662001-01-10 20:13:55 +00001290- The SocketServer module now sets the allow_reuse_address flag by
1291 default in the TCPServer class.
1292
1293- A new function, sys._getframe(), returns the stack frame pointer of
1294 the caller. This is intended only as a building block for
1295 higher-level mechanisms such as string interpolation.
1296
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001297- The pyexpat module supports a number of new handlers, which are
1298 available only in expat 1.2. If invocation of a callback fails, it
1299 will report an additional frame in the traceback. Parser objects
1300 participate now in garbage collection. If expat reports an unknown
1301 encoding, pyexpat will try to use a Python codec; that works only
1302 for single-byte charsets. The parser type objects is exposed as
1303 XMLParserObject.
1304
1305- xml.dom now offers standard definitions for symbolic node type and
1306 exception code constants, and a hierarchy of DOM exceptions. minidom
1307 was adjusted to use them.
1308
1309- The conformance of xml.dom.minidom to the DOM specification was
1310 improved. It detects a number of additional error cases; the
1311 previous/next relationship works even when the tree is modified;
1312 Node supports the normalize() method; NamedNodeMap, DocumentType and
1313 DOMImplementation classes were added; Element supports the
1314 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1315 method.
1316
Guido van Rossumf61f1662001-01-10 20:13:55 +00001317Build issues
1318
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001319- For Unix (and Unix-compatible) builds, configuration and building of
1320 extension modules is now greatly automated. Rather than having to
1321 edit the Modules/Setup file to indicate which modules should be
1322 built and where their include files and libraries are, a
1323 distutils-based setup.py script now takes care of building most
1324 extension modules. All extension modules built this way are built
1325 as shared libraries. Only a few modules that must be linked
1326 statically are still listed in the Setup file; you won't need to
1327 edit their configuration.
1328
1329- Python should now build out of the box on Cygwin. If it doesn't,
1330 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001331
1332- Python now always uses its own (renamed) implementation of getopt()
1333 -- there's too much variation among C library getopt()
1334 implementations.
1335
1336- C++ compilers are better supported; the CXX macro is always set to a
1337 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001338
Tim Petersd92dfe02000-12-12 01:18:41 +00001339Windows changes
1340
1341- select module: By default under Windows, a select() call
1342 can specify no more than 64 sockets. Python now boosts
1343 this Microsoft default to 512. If you need even more than
1344 that, see the MS docs (you'll need to #define FD_SETSIZE
1345 and recompile Python from source).
1346
Guido van Rossumf61f1662001-01-10 20:13:55 +00001347- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1348 subdirectory is no more!
1349
Tim Petersa3a3a032000-11-30 05:22:44 +00001350
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001351What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001352=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001353
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001354Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001355changes are in the file HISTORY. If you are making the jump directly
1356from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1357HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001358
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001359Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1360the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1361http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001362
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001363--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001364
1365======================================================================
1366
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001367What's new in 2.0 (since release candidate 1)?
1368==============================================
1369
1370Standard library
1371
1372- The copy_reg module was modified to clarify its intended use: to
1373 register pickle support for extension types, not for classes.
1374 pickle() will raise a TypeError if it is passed a class.
1375
1376- Fixed a bug in gettext's "normalize and expand" code that prevented
1377 it from finding an existing .mo file.
1378
1379- Restored support for HTTP/0.9 servers in httplib.
1380
Tim Peters989b7b92000-10-16 20:24:53 +00001381- The math module was changed to stop raising OverflowError in case of
1382 underflow, and return 0 instead in underflow cases. Whether Python
1383 used to raise OverflowError in case of underflow was platform-
1384 dependent (it did when the platform math library set errno to ERANGE
1385 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001386
1387- Fixed a bug in StringIO that occurred when the file position was not
1388 at the end of the file and write() was called with enough data to
1389 extend past the end of the file.
1390
1391- Fixed a bug that caused Tkinter error messages to get lost on
1392 Windows. The bug was fixed by replacing direct use of
1393 interp->result with Tcl_GetStringResult(interp).
1394
1395- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1396 redirect response.
1397
1398- Several changes were made to distutils: Some debugging code was
1399 removed from util. Fixed the installer used when an external zip
1400 program (like WinZip) is not found; the source code for this
1401 installer is in Misc/distutils. check_lib() was modified to behave
1402 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1403 test for whether installed modules are on sys.path was changed to
1404 use both normcase() and normpath().
1405
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001406- Several minor bugs were fixed in the xml package (the minidom,
1407 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001408
1409- The regression test driver (regrtest.py) behavior when invoked with
1410 -l changed: It now reports a count of objects that are recognized as
1411 garbage but not freed by the garbage collector.
1412
Tim Peters989b7b92000-10-16 20:24:53 +00001413- The regression test for the math module was changed to test
1414 exceptional behavior when the test is run in verbose mode. Python
1415 cannot yet guarantee consistent exception behavior across platforms,
1416 so the exception part of test_math is run only in verbose mode, and
1417 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001418
1419Internals
1420
1421- PyOS_CheckStack() has been disabled on Win64, where it caused
1422 test_sre to fail.
1423
1424Build issues
1425
1426- Changed compiler flags, so that gcc is always invoked with -Wall and
1427 -Wstrict-prototypes. Users compiling Python with GCC should see
1428 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001429 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001430 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001431
Tim Petersa3a3a032000-11-30 05:22:44 +00001432- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001433
1434Tools and other miscellany
1435
1436- The compiler in Tools/compiler was updated to support the new
1437 language features introduced in 2.0: extended print statement, list
1438 comprehensions, and augmented assignments. The new compiler should
1439 also be backwards compatible with Python 1.5.2; the compiler will
1440 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001441 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001442
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001443What's new in 2.0 release candidate 1 (since beta 2)?
1444=====================================================
1445
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001446What is release candidate 1?
1447
1448We believe that release candidate 1 will fix all known bugs that we
1449intend to fix for the 2.0 final release. This release should be a bit
1450more stable than the previous betas. We would like to see even more
1451widespread testing before the final release, so we are producing this
1452release candidate. The final release will be exactly the same unless
1453any show-stopping (or brown bag) bugs are found by testers of the
1454release candidate.
1455
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001456All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001457to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001458
1459Core language, builtins, and interpreter
1460
1461- A bug that caused crashes when __coerce__ was used with augmented
1462 assignment, e.g. +=, was fixed.
1463
1464- Raise ZeroDivisionError when raising zero to a negative number,
1465 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1466 power operator and the result of math.pow(0.0, -2.0) will vary by
1467 platform. On Linux, it raises a ValueError.
1468
1469- A bug in Unicode string interpolation was fixed that occasionally
1470 caused errors with formats including "%%". For example, the
1471 following expression "%% %s" % u"abc" no longer raises a TypeError.
1472
1473- Compilation of deeply nested expressions raises MemoryError instead
1474 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1475
1476- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1477 rendering them useless. They are now written in binary mode again.
1478
1479Standard library
1480
1481- Keyword arguments are now accepted for most pattern and match object
1482 methods in SRE, the standard regular expression engine.
1483
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001484- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001485 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001486
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001487- Several bugs in the Unicode handling and error handling in _tkinter
1488 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001489
1490- Fix memory management errors in Merge() and Tkapp_Call() routines.
1491
1492- Several changes were made to cStringIO to make it compatible with
1493 the file-like object interface and with StringIO. If operations are
1494 performed on a closed object, an exception is raised. The truncate
1495 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001496 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001497
1498- There were many changes made to the linuxaudiodev module and its
1499 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001500 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001501
1502 Note that this module is named poorly, because it should work
1503 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001504 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001505
1506 The module now raises exceptions when errors occur instead of
1507 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1508 audio) and defines a getptr() method that calls the
1509 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1510
1511- The library_version attribute, introduced in an earlier beta, was
1512 removed because it can not be supported with early versions of the C
1513 readline library, which provides no way to determine the version at
1514 compile-time.
1515
1516- The binascii module is now enabled on Win64.
1517
Tim Peters46446d62000-10-09 21:19:31 +00001518- tokenize.py no longer suffers "recursion depth" errors when parsing
1519 programs with very long string literals.
1520
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001521Internals
1522
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001523- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001524 which is called when the interpreter starts up to determine where
1525 the standard library is installed. These vulnerabilities affect all
1526 previous versions of Python and can be exploited by setting very
1527 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1528 setuid Python script, although use of the wrapper in
1529 Misc/setuid-prog.c will eliminate the vulnerability.
1530
1531- Fixed garbage collection bugs in instance creation that were
1532 triggered when errors occurred during initialization. The solution,
1533 applied in cPickle and in PyInstance_New(), is to call
1534 PyObject_GC_Init() after the initialization of the object's
1535 container attributes is complete.
1536
1537- pyexpat adds definitions of PyModule_AddStringConstant and
1538 PyModule_AddObject if the Python version is less than 2.0, which
1539 provides compatibility with PyXML on Python 1.5.2.
1540
1541- If the platform has a bogus definition for LONG_BIT (the number of
1542 bits in a long), an error will be reported at compile time.
1543
1544- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1545 collection crashes and possibly other, unreported crashes.
1546
1547- Fixed a memory leak in _PyUnicode_Fini().
1548
1549Build issues
1550
1551- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001552 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001553 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001554
1555- The mmap.PAGESIZE constant is now initialized using sysconf when
1556 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1557
1558- The md5 file should now compile on all platforms.
1559
1560- The select module now compiles on platforms that do not define
1561 POLLRDNORM and related constants.
1562
1563- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001564 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001565
Jeremy Hylton10921202000-10-09 18:34:12 +00001566- BeOS: A number of changes were made to the build and installation
1567 process. ar-fake now operates on a directory of object files.
1568 dl_export.h is gone, and its macros now appear on the mwcc command
1569 line during build on PPC BeOS.
1570
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001571- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001572 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001573
1574- Cygwin: Support for shared libraries, Tkinter, and sockets.
1575
1576- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1577
1578Tools and other miscellany
1579
1580- Removed debugging prints from main used with freeze.
1581
Tim Peters46446d62000-10-09 21:19:31 +00001582- IDLE auto-indent no longer crashes when it encounters Unicode
1583 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001584
1585What's new in 2.0 beta 2 (since beta 1)?
1586========================================
1587
1588Core language, builtins, and interpreter
1589
Tim Peters482c0212000-09-26 06:33:09 +00001590- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001591 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001592
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001593- Add -h and -V command line options to print the usage message and
1594 Python version number and exit immediately.
1595
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001596- eval() and exec accept Unicode objects as code parameters.
1597
1598- getattr() and setattr() now also accept Unicode objects for the
1599 attribute name, which are converted to strings using the default
1600 encoding before lookup.
1601
1602- Multiplication on string and Unicode now does proper bounds
1603 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1604 string is too long."
1605
1606- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001607 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001608
Jeremy Hylton1b618592000-09-26 05:32:36 +00001609
1610Standard library and extensions
1611
Guido van Rossum5b08f132001-04-16 02:05:23 +00001612- socket module: the OpenSSL code now adds support for RAND_status()
1613 and EGD (Entropy Gathering Device).
1614
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001615- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001616 argument checking; it still takes no arguments.
1617
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001618- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001619
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001620- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001621
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001622- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001623
1624- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001625 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001626
1627- copy: Copy Unicode objects atomically.
1628
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001629- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001630
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001631- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001632
Fred Drake67233bc2000-09-26 16:40:27 +00001633- dbm: Add get() and setdefault() methods to dbm object. Add constant
1634 `library' to module that names the library used. Added doc strings
1635 and method names to error messages. Uses configure to determine
1636 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
1637 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001638
1639- distutils: Update to version 0.9.3.
1640
1641- dl: Add several dl.RTLD_ constants.
1642
1643- fpectl: Now supported on FreeBSD.
1644
1645- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
1646 found by the collector will be saved in gc.garbage. This is useful
1647 for debugging a program that creates reference cycles.
1648
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001649- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00001650 of HTTP class. Do not close socket on zero-length response. Do not
1651 crash when server sends invalid content-length header.
1652
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001653- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001654
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001655- marshal: When reading a short, sign-extend on platforms where shorts
1656 are bigger than 16 bits. When reading a long, repair the unportable
1657 sign extension that was being done for 64-bit machines. (It assumed
1658 that signed right shift sign-extends.)
1659
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001660- operator: Add contains(), invert(), __invert__() as aliases for
1661 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001662
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001663- os: Add support for popen2() and popen3() on all platforms where
1664 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001665
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001666- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00001667 clicking on a file in Explorer (or passing the file name to the
1668 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001669
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001670- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00001671 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001672
1673- pickle: Now raises ValueError when an invalid pickle that contains
1674 a non-string repr where a string repr was expected. This behavior
1675 matches cPickle.
1676
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001677- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001678
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001679- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001680
1681- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001682 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001683 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001684
1685- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001686 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001687
1688- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00001689 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00001690 few cycles during startup since the first call to
1691 setdefaultencoding() will initialize the codec registry and the
1692 encodings package.
1693
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001694- socket: Support for size hint in readlines() method of object returned
1695 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001696
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001697- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001698 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001699 is followed by whitespace.
1700
Tim Petersa3a3a032000-11-30 05:22:44 +00001701- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001702
1703- struct: Check ranges for bytes and shorts.
1704
1705- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001706 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001707
1708- Tkinter: Image objects are now guaranteed to have unique ids. Set
1709 event.delta to zero if Tk version doesn't support mousewheel.
1710 Removed some debugging prints.
1711
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001712- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001713
Fred Drake67233bc2000-09-26 16:40:27 +00001714- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001715 which works around a bug in Norton AntiVirus 2000 that leads directly
1716 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001717
1718- xml: New version detection code allows PyXML to override standard
1719 XML package if PyXML version is greater than 0.6.1.
1720
Fred Drake64bb3802000-09-26 16:21:35 +00001721- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
1722 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
1723 tree only for nodes which are sufficiently interesting to a specific
1724 application. Does not provide the HTML-specific extensions. Still
1725 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001726
Fred Drake64bb3802000-09-26 16:21:35 +00001727- xml.sax: SAX 2 support for Python, including all the handler
1728 interfaces needed to process XML 1.0 compliant XML. Some
1729 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001730
Fred Drake64bb3802000-09-26 16:21:35 +00001731- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
1732 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001733
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001734
Jeremy Hylton1b618592000-09-26 05:32:36 +00001735C API
1736
1737- Add three new convenience functions for module initialization --
1738 PyModule_AddObject(), PyModule_AddIntConstant(), and
1739 PyModule_AddStringConstant().
1740
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001741- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00001742 removed and add #error to Python.h if NULL isn't defined after
1743 #include of stdio.h.
1744
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001745- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00001746 backwards compatibility (at the source level) with old extensions.
1747
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001748- A wrapper API was added for signal() and sigaction(). Instead of
1749 either function, always use PyOS_getsig() to get a signal handler
1750 and PyOS_setsig() to set one. A new convenience typedef
1751 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001752
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001753- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00001754 internal data buffer and size of a string object -- or the default
1755 encoded version of a Unicode object.
1756
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001757- PyString_Size() and PyString_AsString() accept Unicode objects.
1758
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001759- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00001760 exists). INT_MAX and LONG_MAX will always be defined, even if
1761 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001762
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001763- PyFloat_FromString takes a second argument, pend, that was
1764 effectively useless. It is now officially useless but preserved for
1765 backwards compatibility. If the pend argument is not NULL, *pend is
1766 set to NULL.
1767
1768- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
1769 for the attribute name. See note on getattr() above.
1770
1771- A few bug fixes to argument processing for Unicode.
1772 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
1773 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
1774 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00001775 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001776
1777- Py_BuildValue accepts B format (for bgen-generated code).
1778
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001779
Jeremy Hylton1b618592000-09-26 05:32:36 +00001780Internals
1781
1782- On Unix, fix code for finding Python installation directory so that
1783 it works when argv[0] is a relative path.
1784
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00001785- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001786 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00001787 rather than by generating a copy of the object.
1788
Tim Peters482c0212000-09-26 06:33:09 +00001789- Several of the internal Unicode tables are much smaller now, and
1790 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001791
Jeremy Hylton97693b02000-09-26 17:42:51 +00001792- In the garbage collector: Fixed bug in collection of tuples. Fixed
1793 bug that caused some instances to be removed from the container set
1794 while they were still live. Fixed parsing in gc.set_debug() for
1795 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001796
1797- Fixed refcount problem in instance deallocation that only occurred
1798 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
1799
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001800- On Windows, getpythonregpath is now protected against null data in
1801 registry key.
1802
1803- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00001804 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001805
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001806
Jeremy Hylton1b618592000-09-26 05:32:36 +00001807Build and platform-specific issues
1808
1809- Better support of GNU Pth via --with-pth configure option.
1810
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001811- Python/C API now properly exposed to dynamically-loaded extension
1812 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001813
1814- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
1815 Don't define MS_SYNC to be zero when it is undefined. Added missing
1816 prototypes in posixmodule.c.
1817
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001818- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001819 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001820
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001821- Fix largefile support on older NetBSD systems and OpenBSD by adding
1822 define for TELL64.
1823
1824
1825Tools and other miscellany
1826
1827- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
1828
1829- freeze: The modulefinder now works with 2.0 opcodes.
1830
Tim Petersa3a3a032000-11-30 05:22:44 +00001831- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001832 Move hackery of sys.argv until after the Tk instance has been
1833 created, which allows the application-specific Tkinter
1834 initialization to be executed if present; also pass an explicit
1835 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00001836
Jeremy Hylton1b618592000-09-26 05:32:36 +00001837
1838What's new in 2.0 beta 1?
1839=========================
1840
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001841Source Incompatibilities
1842------------------------
1843
1844None. Note that 1.6 introduced several incompatibilities with 1.5.2,
1845such as single-argument append(), connect() and bind(), and changes to
1846str(long) and repr(float).
1847
1848
1849Binary Incompatibilities
1850------------------------
1851
1852- Third party extensions built for Python 1.5.x or 1.6 cannot be used
1853with Python 2.0; these extensions will have to be rebuilt for Python
18542.0.
1855
1856- On Windows, attempting to import a third party extension built for
1857Python 1.5.x or 1.6 results in an immediate crash; there's not much we
1858can do about this. Check your PYTHONPATH environment variable!
1859
1860- Python bytecode files (*.pyc and *.pyo) are not compatible between
1861releases.
1862
1863
1864Overview of Changes Since 1.6
1865-----------------------------
1866
1867There are many new modules (including brand new XML support through
1868the xml package, and i18n support through the gettext module); a list
1869of all new modules is included below. Lots of bugs have been fixed.
1870
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001871The process for making major new changes to the language has changed
1872since Python 1.6. Enhancements must now be documented by a Python
1873Enhancement Proposal (PEP) before they can be accepted.
1874
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001875There are several important syntax enhancements, described in more
1876detail below:
1877
1878 - Augmented assignment, e.g. x += 1
1879
1880 - List comprehensions, e.g. [x**2 for x in range(10)]
1881
1882 - Extended import statement, e.g. import Module as Name
1883
1884 - Extended print statement, e.g. print >> file, "Hello"
1885
1886Other important changes:
1887
1888 - Optional collection of cyclical garbage
1889
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001890Python Enhancement Proposal (PEP)
1891---------------------------------
1892
1893PEP stands for Python Enhancement Proposal. A PEP is a design
1894document providing information to the Python community, or describing
1895a new feature for Python. The PEP should provide a concise technical
1896specification of the feature and a rationale for the feature.
1897
1898We intend PEPs to be the primary mechanisms for proposing new
1899features, for collecting community input on an issue, and for
1900documenting the design decisions that have gone into Python. The PEP
1901author is responsible for building consensus within the community and
1902documenting dissenting opinions.
1903
1904The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001905
1906Augmented Assignment
1907--------------------
1908
1909This must have been the most-requested feature of the past years!
1910Eleven new assignment operators were added:
1911
Guido van Rossume905e952000-09-05 12:42:46 +00001912 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001913
1914For example,
1915
1916 A += B
1917
1918is similar to
1919
1920 A = A + B
1921
1922except that A is evaluated only once (relevant when A is something
1923like dict[index].attr).
1924
1925However, if A is a mutable object, A may be modified in place. Thus,
1926if A is a number or a string, A += B has the same effect as A = A+B
1927(except A is only evaluated once); but if a is a list, A += B has the
1928same effect as A.extend(B)!
1929
1930Classes and built-in object types can override the new operators in
1931order to implement the in-place behavior; the not-in-place behavior is
1932used automatically as a fallback when an object doesn't implement the
1933in-place behavior. For classes, the method name is derived from the
1934method name for the corresponding not-in-place operator by inserting
1935an 'i' in front of the name, e.g. __iadd__ implements in-place
1936__add__.
1937
1938Augmented assignment was implemented by Thomas Wouters.
1939
1940
1941List Comprehensions
1942-------------------
1943
1944This is a flexible new notation for lists whose elements are computed
1945from another list (or lists). The simplest form is:
1946
1947 [<expression> for <variable> in <sequence>]
1948
Guido van Rossum56db0952000-09-06 23:34:25 +00001949For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001950This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001951
1952You can also add a condition:
1953
1954 [<expression> for <variable> in <sequence> if <condition>]
1955
1956For example, [w for w in words if w == w.lower()] would yield the list
1957of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001958than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001959
1960You can also have nested for loops and more than one 'if' clause. For
1961example, here's a function that flattens a sequence of sequences::
1962
1963 def flatten(seq):
1964 return [x for subseq in seq for x in subseq]
1965
1966 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
1967
1968This prints
1969
1970 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
1971
1972List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001973Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001974
1975
1976Extended Import Statement
1977-------------------------
1978
1979Many people have asked for a way to import a module under a different
1980name. This can be accomplished like this:
1981
1982 import foo
1983 bar = foo
1984 del foo
1985
1986but this common idiom gets old quickly. A simple extension of the
1987import statement now allows this to be written as follows:
1988
1989 import foo as bar
1990
1991There's also a variant for 'from ... import':
1992
1993 from foo import bar as spam
1994
1995This also works with packages; e.g. you can write this:
1996
1997 import test.regrtest as regrtest
1998
1999Note that 'as' is not a new keyword -- it is recognized only in this
2000context (this is only possible because the syntax for the import
2001statement doesn't involve expressions).
2002
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002003Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002004
2005
2006Extended Print Statement
2007------------------------
2008
2009Easily the most controversial new feature, this extension to the print
2010statement adds an option to make the output go to a different file
2011than the default sys.stdout.
2012
2013For example, to write an error message to sys.stderr, you can now
2014write:
2015
2016 print >> sys.stderr, "Error: bad dog!"
2017
2018As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002019evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002020
2021 print >> None, "Hello world"
2022
2023is equivalent to
2024
2025 print "Hello world"
2026
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002027Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002028
2029
2030Optional Collection of Cyclical Garbage
2031---------------------------------------
2032
2033Python is now equipped with a garbage collector that can hunt down
2034cyclical references between Python objects. It's no replacement for
2035reference counting; in fact, it depends on the reference counts being
2036correct, and decides that a set of objects belong to a cycle if all
2037their reference counts can be accounted for from their references to
2038each other. This devious scheme was first proposed by Eric Tiedemann,
2039and brought to implementation by Neil Schemenauer.
2040
2041There's a module "gc" that lets you control some parameters of the
2042garbage collection. There's also an option to the configure script
2043that lets you enable or disable the garbage collection. In 2.0b1,
2044it's on by default, so that we (hopefully) can collect decent user
2045experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002046performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002047off by default in the final 2.0 release.
2048
2049
2050Smaller Changes
2051---------------
2052
2053A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2054map(None, seq1, seq2, ...) when the sequences have the same length;
2055i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2056the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002057zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002058
2059sys.version_info is a tuple (major, minor, micro, level, serial).
2060
2061Dictionaries have an odd new method, setdefault(key, default).
2062dict.setdefault(key, default) returns dict[key] if it exists; if not,
2063it sets dict[key] to default and returns that value. Thus:
2064
2065 dict.setdefault(key, []).append(item)
2066
2067does the same work as this common idiom:
2068
2069 if not dict.has_key(key):
2070 dict[key] = []
2071 dict[key].append(item)
2072
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002073There are two new variants of SyntaxError that are raised for
2074indentation-related errors: IndentationError and TabError.
2075
2076Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2077escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002078
2079The limits on the size of expressions and file in Python source code
2080have been raised from 2**16 to 2**32. Previous versions of Python
2081were limited because the maximum argument size the Python VM accepted
2082was 2**16. This limited the size of object constructor expressions,
2083e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2084limit was raised thanks to a patch by Charles Waldman that effectively
2085fixes the problem. It is now much more likely that you will be
2086limited by available memory than by an arbitrary limit in Python.
2087
2088The interpreter's maximum recursion depth can be modified by Python
2089programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2090limit is the maximum number of recursive calls that can be made by
2091Python code. The limit exists to prevent infinite recursion from
2092overflowing the C stack and causing a core dump. The default value is
20931000. The maximum safe value for a particular platform can be found
2094by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002095
2096New Modules and Packages
2097------------------------
2098
2099atexit - for registering functions to be called when Python exits.
2100
2101imputil - Greg Stein's alternative API for writing custom import
2102hooks.
2103
2104pyexpat - an interface to the Expat XML parser, contributed by Paul
2105Prescod.
2106
2107xml - a new package with XML support code organized (so far) in three
2108subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2109would fill a volume. There's a special feature whereby a
2110user-installed package named _xmlplus overrides the standard
2111xmlpackage; this is intended to give the XML SIG a hook to distribute
2112backwards-compatible updates to the standard xml package.
2113
2114webbrowser - a platform-independent API to launch a web browser.
2115
2116
Guido van Rossume905e952000-09-05 12:42:46 +00002117Changed Modules
2118---------------
2119
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002120array -- new methods for array objects: count, extend, index, pop, and
2121remove
2122
2123binascii -- new functions b2a_hex and a2b_hex that convert between
2124binary data and its hex representation
2125
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002126calendar -- Many new functions that support features including control
2127over which day of the week is the first day, returning strings instead
2128of printing them. Also new symbolic constants for days of week,
2129e.g. MONDAY, ..., SUNDAY.
2130
2131cgi -- FieldStorage objects have a getvalue method that works like a
2132dictionary's get method and returns the value attribute of the object.
2133
2134ConfigParser -- The parser object has new methods has_option,
2135remove_section, remove_option, set, and write. They allow the module
2136to be used for writing config files as well as reading them.
2137
2138ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002139optionally support the RFC 959 REST command.
2140
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002141gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002142
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002143httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2144the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002145
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002146locale -- implement getdefaultlocale for Win32 and Macintosh
2147
2148marshal -- no longer dumps core when marshaling deeply nested or
2149recursive data structures
2150
2151os -- new functions isatty, seteuid, setegid, setreuid, setregid
2152
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002153os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2154support under Unix.
2155
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002156os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002157
2158os.path -- fix semantics of os.path.commonprefix
2159
2160smtplib -- support for sending very long messages
2161
2162socket -- new function getfqdn()
2163
2164readline -- new functions to read, write and truncate history files.
2165The readline section of the library reference manual contains an
2166example.
2167
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002168select -- add interface to poll system call
2169
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002170shutil -- new copyfileobj function
2171
2172SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2173HTTP server.
2174
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002175Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002176
2177urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002178e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002179
2180whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002181
2182
2183Obsolete Modules
2184----------------
2185
2186None. However note that 1.6 made a whole slew of modules obsolete:
2187stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2188poly, zmod, strop, util, whatsound.
2189
2190
2191Changed, New, Obsolete Tools
2192----------------------------
2193
Tim Peters8b092332000-09-05 20:15:25 +00002194None.
Guido van Rossume905e952000-09-05 12:42:46 +00002195
2196
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002197C-level Changes
2198---------------
2199
2200Several cleanup jobs were carried out throughout the source code.
2201
2202All C code was converted to ANSI C; we got rid of all uses of the
2203Py_PROTO() macro, which makes the header files a lot more readable.
2204
2205Most of the portability hacks were moved to a new header file,
2206pyport.h; several other new header files were added and some old
2207header files were removed, in an attempt to create a more rational set
2208of header files. (Few of these ever need to be included explicitly;
2209they are all included by Python.h.)
2210
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002211Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002212and Win64, especially for the new Intel Itanium processor. Mick also
2213added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002214
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002215The C APIs to return an object's size have been update to consistently
2216use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2217previous versions, the abstract interfaces used PyXXX_Length and the
2218concrete interfaces used PyXXX_Size. The old names,
2219e.g. PyObject_Length, are still available for backwards compatibility
2220at the API level, but are deprecated.
2221
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002222The PyOS_CheckStack function has been implemented on Windows by
2223Fredrik Lundh. It prevents Python from failing with a stack overflow
2224on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002225
2226The GC changes resulted in creation of two new slots on object,
2227tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002228the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002229
2230The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002231C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002232
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002233PyErr_Format has been updated to automatically calculate the size of
2234the buffer needed to hold the formatted result string. This change
2235prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002236
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002237New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002238
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002239PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2240that are the same as their non-Ex counterparts except they take an
2241extra flag argument that tells them to close the file when done.
2242
2243XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002244
Tim Peters8b092332000-09-05 20:15:25 +00002245
2246Windows Changes
2247---------------
2248
2249New popen2/popen3/peopen4 in os module (see Changed Modules above).
2250
2251os.popen is much more usable on Windows 95 and 98. See Microsoft
2252Knowledge Base article Q150956. The Win9x workaround described there
2253is implemented by the new w9xpopen.exe helper in the root of your
2254Python installation. Note that Python uses this internally; it is not
2255a standalone program.
2256
2257Administrator privileges are no longer required to install Python
2258on Windows NT or Windows 2000. If you have administrator privileges,
2259Python's registry info will be written under HKEY_LOCAL_MACHINE.
2260Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002261under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002262uses of Python, but will prevent some advanced uses from working
2263(for example, running a Python script as an NT service, or possibly
2264from CGI).
2265
2266[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2267installer; instead, it installs the needed Tcl/Tk files directly in the
2268Python directory. If you already have a Tcl/Tk installation, this
2269wastes some disk space (about 4 Megs) but avoids problems with
2270conflicting Tcl/Tk installations, and makes it much easier for Python
2271to ensure that Tcl/Tk can find all its files.
2272
2273[This was new in 1.6] The Windows installer now installs by default in
2274\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2275
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002276
2277Updates to the changes between 1.5.2 and 1.6
2278--------------------------------------------
2279
2280The 1.6 NEWS file can't be changed after the release is done, so here
2281is some late-breaking news:
2282
2283New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2284and changes to getlocale() and setlocale().
2285
2286The new module is now enabled per default.
2287
2288It is not true that the encodings codecs cannot be used for normal
2289strings: the string.encode() (which is also present on 8-bit strings
2290!) allows using them for 8-bit strings too, e.g. to convert files from
2291cp1252 (Windows) to latin-1 or vice-versa.
2292
2293Japanese codecs are available from Tamito KAJIYAMA:
2294http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2295
2296
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002297======================================================================