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Tim Peters20f51a72001-07-21 02:31:40 +00001What's New in Python 2.2a2?
2===========================
3
4Tests
5
Tim Peters5e824c32001-08-12 22:25:01 +00006- regrtest.py now knows which tests are expected to be skipped on some
7 platforms, allowing to give clearer test result output.
8
Tim Peters20f51a72001-07-21 02:31:40 +00009- Several new tests in the standard test suite, with special thanks to
10 Nick Mathewson.
11
12Core
13
Marc-André Lemburg888fac02001-07-31 14:24:31 +000014- Warnings about a mismatch in the Python API during extension import
15 now use the Python warning framework (which makes it possible to
16 write filters for these warnings).
17
Barry Warsaw9b3be7f2001-08-14 18:35:02 +000018- A function's __dict__ (aka func_dict) will now always be a
19 dictionary. It used to be possible to delete it or set it to None,
20 but now both actions raise TypeErrors. It is still legal to set it
21 to a dictionary object. Getting func.__dict__ before any attributes
22 have been assigned now returns an empty dictionary instead of None.
23
Marc-André Lemburgd6277912001-07-31 14:42:42 +000024Library
25
Tim Peters5e824c32001-08-12 22:25:01 +000026- New class Differ and new functions ndiff() and restore() in difflib.py.
27 These package the algorithms used by the popular Tools/scripts/ndiff.py,
28 for progammatic reuse.
29
Marc-André Lemburgd6277912001-07-31 14:42:42 +000030- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
31 value using the minimal quoting required for the value; more
32 reliable than using xml.sax.saxutils.escape() for attribute values.
33
34- Readline completion support for cmd.Cmd was added.
35
36New platforms
37
38C API
39
Marc-André Lemburg888fac02001-07-31 14:24:31 +000040- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
41 which provide a cross-platform implementations for the
42 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
43 the standard sprintf() and vsprintf() C lib APIs, these versions
44 apply bounds checking on the used buffer which enhances protection
45 against buffer overruns.
46
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +000047- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +000048 and extensions using different Unicode widths is rendered next to
49 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +000050 will result in an ImportError. Unicode extensions writers must make
51 sure to check the Unicode width compatibility in their extensions by
52 using at least one of the mangled Unicode APIs in the extension.
53
Tim Petersc1731372001-08-04 08:12:36 +000054Windows
55
56- "import module" now compiles module.pyw if it exists and nothing else
57 relevant is found.
58
Tim Peters20f51a72001-07-21 02:31:40 +000059
Guido van Rossum55a78992001-07-17 17:22:32 +000060What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +000061===========================
62
63Core
Tim Petersa814db52001-05-14 07:05:58 +000064
Tim Peters6d6c1a32001-08-02 04:15:00 +000065- TENTATIVELY, a large amount of code implementing much of what's
66 described in PEP 252 (Making Types Look More Like Classes) and PEP
67 253 (Subtyping Built-in Types) was added. This will be released
68 with Python 2.2a1. Documentation will be provided separately
69 through http://www.python.org/2.2/. The purpose of releasing this
70 with Python 2.2a1 is to test backwards compatibility. It is
71 possible, though not likely, that a decision is made not to release
72 this code as part of 2.2 final, if any serious backwards
73 incompapatibilities are found during alpha testing that cannot be
74 repaired.
75
Guido van Rossum55a78992001-07-17 17:22:32 +000076- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +000077 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +000078 more 'yield' statements. See PEP 255. Since this adds a new
79 keyword to the language, this feature must be enabled by including a
80 future statement: "from __future__ import generators" (see PEP 236).
81 Generators will become a standard feature in a future release
82 (probably 2.3). Without this future statement, 'yield' remains an
83 ordinary identifier, but a warning is issued each time it is used.
84 (These warnings currently don't conform to the warnings framework of
85 PEP 230; we intend to fix this in 2.2a2.)
86
Marc-André Lemburg12e74b32001-05-22 08:58:23 +000087- The UTF-16 codec was modified to be more RFC compliant. It will now
88 only remove BOM characters at the start of the string and then
89 only if running in native mode (UTF-16-LE and -BE won't remove a
90 leading BMO character).
91
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +000092- Strings now have a new method .decode() to complement the already
93 existing .encode() method. These two methods provide direct access
94 to the corresponding decoders and encoders of the registered codecs.
95
96 To enhance the usability of the .encode() method, the special
97 casing of Unicode object return values was dropped (Unicode objects
98 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +000099
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000100 Both methods will now return whatever the codec in charge of the
101 requested encoding returns as object, e.g. Unicode codecs will
102 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
103 will return u"äöü"). This enables codec writer to create codecs
104 for various simple to use conversions.
105
106 New codecs were added to demonstrate these new features (the .encode()
107 and .decode() columns indicate the type of the returned objects):
108
109 Name | .encode() | .decode() | Description
110 ----------------------------------------------------------------------
111 uu | string | string | UU codec (e.g. for email)
112 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000113 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000114 zlib | string | string | zlib compression
115 hex | string | string | 2-byte hex codec
116 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
117
Mark Hammond2a0af792001-05-14 03:09:36 +0000118- Some operating systems now support the concept of a default Unicode
119 encoding for file system operations. Notably, Windows supports 'mbcs'
120 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000121 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000122 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000123
124 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000125 functions that return filenames (such as os.listdir()) to return Python
126 string objects pre-encoded using the default file system encoding for
127 the platform. As this encoding is likely to be different from Python's
128 default encoding, converting this name to a Unicode object before passing
129 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000130 would attempt to use its default encoding (generally ASCII) rather than
131 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000132
Tim Petersa814db52001-05-14 07:05:58 +0000133 In general, this change simply removes surprises when working with
134 Unicode and the file system, making these operations work as you expect,
135 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000136 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000137
Tim Peters61dff2b2001-05-08 15:43:37 +0000138- Float (and complex) literals in source code were evaluated to full
139 precision only when running from a .py file; the same code loaded from a
140 .pyc (or .pyo) file could suffer numeric differences starting at about the
141 12th significant decimal digit. For example, on a machine with IEEE-754
142 floating arithmetic,
143
144 x = 9007199254740992.0
145 print long(x)
146
147 printed 9007199254740992 if run directly from .py, but 9007199254740000
148 if from a compiled (.pyc or .pyo) file. This was due to marshal using
149 str(float) instead of repr(float) when building code objects. marshal
150 now uses repr(float) instead, which should reproduce floats to full
151 machine precision (assuming the platform C float<->string I/O conversion
152 functions are of good quality).
153
154 This may cause floating-point results to change in some cases, and
155 usually for the better, but may also cause numerically unstable
156 algorithms to break.
157
Tim Peters2f228e72001-05-13 00:19:31 +0000158- The implementation of dicts suffers fewer collisions, which has speed
159 benefits. However, the order in which dict entries appear in dict.keys(),
160 dict.values() and dict.items() may differ from previous releases for a
161 given dict. Nothing is defined about this order, so no program should
162 rely on it. Nevertheless, it's easy to write test cases that rely on the
163 order by accident, typically because of printing the str() or repr() of a
164 dict to an "expected results" file. See Lib/test/test_support.py's new
165 sortdict(dict) function for a simple way to display a dict in sorted
166 order.
167
Tim Peters7a3bfc32001-06-12 01:22:22 +0000168- Many other small changes to dicts were made, resulting in faster
169 operation along the most common code paths.
170
Guido van Rossum10315822001-05-01 20:54:30 +0000171- Dictionary objects now support the "in" operator: "x in dict" means
172 the same as dict.has_key(x).
173
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000174- The update() method of dictionaries now accepts generic mapping
175 objects. Specifically the argument object must support the .keys()
176 and __getitem__() methods. This allows you to say, for example,
177 {}.update(UserDict())
178
Guido van Rossum10315822001-05-01 20:54:30 +0000179- Iterators were added; this is a generalized way of providing values
180 to a for loop. See PEP 234. There's a new built-in function iter()
181 to return an iterator. There's a new protocol to get the next value
182 from an iterator using the next() method (in Python) or the
183 tp_iternext slot (in C). There's a new protocol to get iterators
184 using the __iter__() method (in Python) or the tp_iter slot (in C).
185 Iterating (i.e. a for loop) over a dictionary generates its keys.
186 Iterating over a file generates its lines.
187
Tim Petersf553f892001-05-01 20:45:31 +0000188- The following functions were generalized to work nicely with iterator
189 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000190 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000191 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
192 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000193 join() method of strings
194 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000195 'x in y' and 'x not in y' (PySequence_Contains() in C API)
196 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000197 right-hand side of assignment statements with multiple targets, such as
198 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000199
Tim Petersd85e1022001-05-11 21:51:48 +0000200- Accessing module attributes is significantly faster (for example,
201 random.random or os.path or yourPythonModule.yourAttribute).
202
Tim Peterse63415e2001-05-08 04:38:29 +0000203- Comparing dictionary objects via == and != is faster, and now works even
204 if the keys and values don't support comparisons other than ==.
205
Tim Peters95bf9392001-05-10 08:32:44 +0000206- Comparing dictionaries in ways other than == and != is slower: there were
207 insecurities in the dict comparison implementation that could cause Python
208 to crash if the element comparison routines for the dict keys and/or
209 values mutated the dicts. Making the code bulletproof slowed it down.
210
Tim Peterseb28ef22001-06-02 05:27:19 +0000211- Collisions in dicts are resolved via a new approach, which can help
212 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000213 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000214 faster now. Thanks to Christian Tismer for pointing out the cause and
215 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000216
Tim Peters52e155e2001-06-16 05:42:57 +0000217- repr() is much faster for large containers (dict, list, tuple).
218
219
Tim Petersa814db52001-05-14 07:05:58 +0000220Library
221
Fred Drake960fdf92001-07-20 18:38:26 +0000222- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
223 were added to the string module. These a locale-indenpendent
224 constants, unlike letters, lowercase, and uppercase. These are now
225 use in appropriate locations in the standard library.
226
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000227- The flags used in dlopen calls can now be configured using
228 sys.setdlopenflags and queried using sys.getdlopenflags.
229
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000230- Fredrik Lundh's xmlrpclib is now a standard library module. This
231 provides full client-side XML-RPC support. In addition,
232 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
233 one asyncore-based). Thanks to Eric Raymond for the documentation.
234
Guido van Rossum643d3912001-07-05 14:46:25 +0000235- The xrange() object is simplified: it no longer supports slicing,
236 repetition, comparisons, efficient 'in' checking, the tolist()
237 method, or the start, stop and step attributes. See PEP 260.
238
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000239- A new function fnmatch.filter to filter lists of file names was added.
240
Barry Warsawffd674d2001-05-22 16:00:10 +0000241- calendar.py uses month and day names based on the current locale.
242
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000243- strop is now *really* obsolete (this was announced before with 1.6),
244 and issues DeprecationWarning when used (except for the four items
245 that are still imported into string.py).
246
Tim Petersa814db52001-05-14 07:05:58 +0000247- Cookie.py now sorts key+value pairs by key in output strings.
248
249- pprint.isrecursive(object) didn't correctly identify recursive objects.
250 Now it does.
251
Tim Peters95b3f782001-05-14 18:39:41 +0000252- pprint functions now much faster for large containers (tuple, list, dict).
253
Tim Peters7b9542a2001-06-10 23:40:19 +0000254- New 'q' and 'Q' format codes in the struct module, corresponding to C
255 types "long long" and "unsigned long long" (on Windows, __int64). In
256 native mode, these can be used only when the platform C compiler supports
257 these types (when HAVE_LONG_LONG is #define'd by the Python config
258 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000259 In standard mode, 'q' and 'Q' are supported on all platforms, and are
260 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000261
Guido van Rossum83213cc2001-06-12 16:48:52 +0000262- The site module installs a new built-in function 'help' that invokes
263 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
264 it displays a message reminding the user to use 'help()' or
265 'help(object)'.
266
Tim Petersa814db52001-05-14 07:05:58 +0000267Tests
268
269- New test_mutants.py runs dict comparisons where the key and value
270 comparison operators mutute the dicts randomly during comparison. This
271 rapidly causes Python to crash under earlier releases (not for the faint
272 of heart: it can also cause Win9x to freeze or reboot!).
273
274- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000275 pprint.isreadable() return sensible results. Also verifies that simple
276 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000277
Tim Peters58e0a8c2001-05-14 22:32:33 +0000278New platforms
279
280- Python should compile and run out of the box using the Borland C
281 compiler (under Windows), thanks to Stephen Hansen.
Tim Petersf553f892001-05-01 20:45:31 +0000282
Tim Peters4324aa32001-05-28 22:30:08 +0000283C API
284
285- Removed the unused last_is_sticky argument from the internal
286 _PyTuple_Resize(). If this affects you, you were cheating.
287
288
Guido van Rossum55a78992001-07-17 17:22:32 +0000289======================================================================
290
291
Guido van Rossumffe13be2001-04-16 18:46:45 +0000292What's New in Python 2.1 (final)?
293=================================
294
295We only changed a few things since the last release candidate, all in
296Python library code:
297
298- A bug in the locale module was fixed that affected locales which
299 define no grouping for numeric formatting.
300
301- A few bugs in the weakref module's implementations of weak
302 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
303 and the test suite was updated to check for these bugs.
304
305- An old bug in the os.path.walk() function (introduced in Python
306 2.0!) was fixed: a non-existent file would cause an exception
307 instead of being ignored.
308
309- Fixed a few bugs in the new symtable module found by Neil Norwitz's
310 PyChecker.
311
312
Guido van Rossum5b08f132001-04-16 02:05:23 +0000313What's New in Python 2.1c2?
314===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000315
Guido van Rossum5b08f132001-04-16 02:05:23 +0000316A flurry of small changes, and one showstopper fixed in the nick of
317time made it necessary to release another release candidate. The list
318here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000319
Guido van Rossum5b08f132001-04-16 02:05:23 +0000320Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000321
Guido van Rossum5b08f132001-04-16 02:05:23 +0000322- Tim discovered a nasty bug in the dictionary code, caused by
323 PyDict_Next() calling dict_resize(), and the GC code's use of
324 PyDict_Next() violating an assumption in dict_items(). This was
325 fixed with considerable amounts of band-aid, but the net effect is a
326 saner and more robust implementation.
327
328- Made a bunch of symbols static that were accidentally global.
329
330Build and Ports
331
332- The setup.py script didn't check for a new enough version of zlib
333 (1.1.3 is needed). Now it does.
334
335- Changed "make clean" target to also remove shared libraries.
336
337- Added a more general warning about the SGI Irix optimizer to README.
338
339Library
340
341- Fix a bug in urllib.basejoin("http://host", "../file.html") which
342 omitted the slash between host and file.html.
343
344- The mailbox module's _Mailbox class contained a completely broken
345 and undocumented seek() method. Ripped it out.
346
347- Fixed a bunch of typos in various library modules (urllib2, smtpd,
348 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
349
350- Fixed a few last-minute bugs in unittest.
351
352Extensions
353
354- Reverted the patch to the OpenSSL code in socketmodule.c to support
355 RAND_status() and the EGD, and the subsequent patch that tried to
356 fix it for pre-0.9.5 versions; the problem with the patch is that on
357 some systems it issues a warning whenever socket is imported, and
358 that's unacceptable.
359
360Tests
361
362- Fixed the pickle tests to work with "import test.test_pickle".
363
364- Tweaked test_locale.py to actually run the test Windows.
365
366- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
367 not "wb" (which is not a valid mode at all).
368
369- Fix pstats browser crashes. Import readline if it exists to make
370 the user interface nicer.
371
372- Add "import thread" to the top of test modules that import the
373 threading module (test_asynchat and test_threadedtempfile). This
374 prevents test failures caused by a broken threading module resulting
375 from a previously caught failed import.
376
377- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
378 needed on some platforms (e.g. Solaris 8) when the tests are run
379 twice in succession.
380
381- Skip rather than fail test_sunaudiodev if no audio device is found.
382
383
384What's New in Python 2.1c1?
385===========================
386
387This list was significantly updated when 2.1c2 was released; the 2.1c1
388release didn't mention most changes that were actually part of 2.1c1:
389
390Legal
391
392- Copyright was assigned to the Python Software Foundation (PSF) and a
393 PSF license (very similar to the CNRI license) was added.
394
395- The CNRI copyright notice was updated to include 2001.
396
397Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000398
Guido van Rossumc9932722001-04-12 02:31:27 +0000399- After a public outcry, assignment to __debug__ is no longer illegal;
400 instead, a warning is issued. It will become illegal in 2.2.
401
Guido van Rossum5b08f132001-04-16 02:05:23 +0000402- Fixed a core dump with "%#x" % 0, and changed the semantics so that
403 "%#x" now always prepends "0x", even if the value is zero.
404
405- Fixed some nits in the bytecode compiler.
406
407- Fixed core dumps when calling certain kinds of non-functions.
408
409- Fixed various core dumps caused by reference count bugs.
410
411Build and Ports
412
413- Use INSTALL_SCRIPT to install script files.
414
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000415- New port: SCO Unixware 7, by Billy G. Allie.
416
Guido van Rossum5b08f132001-04-16 02:05:23 +0000417- Updated RISCOS port.
418
419- Updated BeOS port and notes.
420
421- Various other porting problems resolved.
422
423Library
424
425- The TERMIOS and SOCKET modules are now truly obsolete and
426 unnecessary. Their symbols are incorporated in the termios and
427 socket modules.
428
429- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
430 better tests for pickling.
431
432- threading: make Condition.wait() robust against KeyboardInterrupt.
433
434- zipfile: add support to zipfile to support opening an archive
435 represented by an open file rather than a file name. Fix bug where
436 the archive was not properly closed. Fixed a bug in this bugfix
437 where flush() was called for a read-only file.
438
439- imputil: added an uninstall() method to the ImportManager.
440
441- Canvas: fixed bugs in lower() and tkraise() methods.
442
443- SocketServer: API change (added overridable close_request() method)
444 so that the TCP server can explicitly close the request.
445
446- pstats: Eric Raymond added a simple interactive statistics browser,
447 invoked when the module is run as a script.
448
449- locale: fixed a problem in format().
450
451- webbrowser: made it work when the BROWSER environment variable has a
452 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
453 KDE 2. Fixed some other nits.
454
455- unittest: changes to allow using a different exception than
456 AssertionError, and added a few more function aliases. Some other
457 small changes.
458
459- urllib, urllib2: fixed redirect problems and a coupleof other nits.
460
461- asynchat: fixed a critical bug in asynchat that slipped through the
462 2.1b2 release. Fixed another rare bug.
463
464- Fix some unqualified except: clauses (always a bad code example).
465
466XML
467
468- pyexpat: new API get_version_string().
469
470- Fixed some minidom bugs.
471
472Extensions
473
474- Fixed a core dump in _weakref. Removed the weakref.mapping()
475 function (it adds nothing to the API).
476
477- Rationalized the use of header files in the readline module, to make
478 it compile (albeit with some warnings) with the very recent readline
479 4.2, without breaking for earlier versions.
480
481- Hopefully fixed a buffering problem in linuxaudiodev.
482
483- Attempted a fix to make the OpenSSL support in the socket module
484 work again with pre-0.9.5 versions of OpenSSL.
485
486Tests
487
488- Added a test case for asynchat and asyncore.
489
490- Removed coupling between tests where one test failing could break
491 another.
492
493Tools
494
495- Ping added an interactive help browser to pydoc, fixed some nits
496 in the rest of the pydoc code, and added some features to his
497 inspect module.
498
499- An updated python-mode.el version 4.1 which integrates Ken
500 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
501 much nicer in XEmacs and Emacs. When stepping through your program
502 with pdb, in either the shell window or the *Python* window, the
503 source file and line will be tracked by an arrow. Very cool!
504
505- IDLE: syntax warnings in interactive mode are changed into errors.
506
507- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +0000508 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +0000509
510- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000511
Barry Warsaw11e89c72001-04-11 20:37:57 +0000512
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000513What's New in Python 2.1 beta 2?
514================================
515
Guido van Rossum053ae352001-03-22 14:17:21 +0000516(Unlisted are many fixed bugs, more documentation, etc.)
517
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000518Core language, builtins, and interpreter
519
Guido van Rossum053ae352001-03-22 14:17:21 +0000520- The nested scopes work (enabled by "from __future__ import
521 nested_scopes") is completed; in particular, the future now extends
522 into code executed through exec, eval() and execfile(), and into the
523 interactive interpreter.
524
525- When calling a base class method (e.g. BaseClass.__init__(self)),
526 this is now allowed even if self is not strictly spoken a class
527 instance (e.g. when using metaclasses or the Don Beaudry hook).
528
529- Slice objects are now comparable but not hashable; this prevents
530 dict[:] from being accepted but meaningless.
531
532- Complex division is now calculated using less braindead algorithms.
533 This doesn't change semantics except it's more likely to give useful
534 results in extreme cases. Complex repr() now uses full precision
535 like float repr().
536
537- sgmllib.py now calls handle_decl() for simple <!...> declarations.
538
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000539- It is illegal to assign to the name __debug__, which is set when the
540 interpreter starts. It is effectively a compile-time constant.
541
542- A warning will be issued if a global statement for a variable
543 follows a use or assignment of that variable.
544
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000545Standard library
546
Guido van Rossum053ae352001-03-22 14:17:21 +0000547- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
548 inspired by JUnit), is now part of the standard library. You now
549 have a choice of two testing frameworks: unittest requires you to
550 write testcases as separate code, doctest gathers them from
551 docstrings. Both approaches have their advantages and
552 disadvantages.
553
554- A new module Tix was added, which wraps the Tix extension library
555 for Tk. With that module, it is not necessary to statically link
556 Tix with _tkinter, since Tix will be loaded with Tcl's "package
557 require" command. See Demo/tix/.
558
559- tzparse.py is now obsolete.
560
561- In gzip.py, the seek() and tell() methods are removed -- they were
562 non-functional anyway, and it's better if callers can test for their
563 existence with hasattr().
564
565Python/C API
566
567- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
568 that's already in the dictionary during a PyDict_Next() iteration.
569 This used to fail occasionally when a dictionary resize operation
570 could be triggered that would rehash all the keys. All other
571 modifications to the dictionary are still off-limits during a
572 PyDict_Next() iteration!
573
574- New extended APIs related to passing compiler variables around.
575
576- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
577 implement isinstance() and issubclass().
578
579- Py_BuildValue() now has a "D" conversion to create a Python complex
580 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000581
Fred Drake4e262a92001-03-22 18:26:47 +0000582- Extensions types which support weak references must now set the
583 field allocated for the weak reference machinery to NULL themselves;
584 this is done to avoid the cost of checking each object for having a
585 weakly referencable type in PyObject_INIT(), since most types are
586 not weakly referencable.
587
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000588- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
589 free variables and cell variables to and from the frame's f_locals.
590
591- Variants of several functions defined in pythonrun.h have been added
592 to support the nested_scopes future statement. The variants all end
593 in Flags and take an extra argument, a PyCompilerFlags *; examples:
594 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
595 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +0000596 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000597
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000598Distutils
599
600- the sdist command now writes a PKG-INFO file, as described in PEP 241,
601 into the release tree.
602
Tim Peters0e57abf2001-05-02 07:39:38 +0000603- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000604 (an uninstaller, more customization of the installer's display)
605
606- from Jack Jansen: added Mac-specific code to generate a dialog for
607 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +0000608 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000609 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +0000610
611- added 'platforms' and 'keywords' to the set of metadata that can be
612 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000613
614- applied patches from Jason Tishler to make the compiler class work with
615 Cygwin.
616
617
Tim Peters2fe289a2001-03-01 22:19:38 +0000618What's New in Python 2.1 beta 1?
619================================
Tim Petersd66595f2001-02-04 03:09:53 +0000620
621Core language, builtins, and interpreter
622
Guido van Rossum9d0fbde2001-03-02 14:00:32 +0000623- Following an outcry from the community about the amount of code
624 broken by the nested scopes feature introduced in 2.1a2, we decided
625 to make this feature optional, and to wait until Python 2.2 (or at
626 least 6 months) to make it standard. The option can be enabled on a
627 per-module basis by adding "from __future__ import nested_scopes" at
628 the beginning of a module (before any other statements, but after
629 comments and an optional docstring). See PEP 236 (Back to the
630 __future__) for a description of the __future__ statement. PEP 227
631 (Statically Nested Scopes) has been updated to reflect this change,
632 and to clarify the semantics in a number of endcases.
633
634- The nested scopes code, when enabled, has been hardened, and most
635 bugs and memory leaks in it have been fixed.
636
637- Compile-time warnings are now generated for a number of conditions
638 that will break or change in meaning when nested scopes are enabled:
639
640 - Using "from...import *" or "exec" without in-clause in a function
641 scope that also defines a lambda or nested function with one or
642 more free (non-local) variables. The presence of the import* or
643 bare exec makes it impossible for the compiler to determine the
644 exact set of local variables in the outer scope, which makes it
645 impossible to determine the bindings for free variables in the
646 inner scope. To avoid the warning about import *, change it into
647 an import of explicitly name object, or move the import* statement
648 to the global scope; to avoid the warning about bare exec, use
649 exec...in... (a good idea anyway -- there's a possibility that
650 bare exec will be deprecated in the future).
651
652 - Use of a global variable in a nested scope with the same name as a
653 local variable in a surrounding scope. This will change in
654 meaning with nested scopes: the name in the inner scope will
655 reference the variable in the outer scope rather than the global
656 of the same name. To avoid the warning, either rename the outer
657 variable, or use a global statement in the inner function.
658
Neil Schemenauera35c6882001-02-27 04:45:05 +0000659- An optional object allocator has been included. This allocator is
660 optimized for Python objects and should be faster and use less memory
661 than the standard system allocator. It is not enabled by default
662 because of possible thread safety problems. The allocator is only
663 protected by the Python interpreter lock and it is possible that some
664 extension modules require a thread safe allocator. The object
665 allocator can be enabled by providing the "--with-pymalloc" option to
666 configure.
667
Tim Petersd66595f2001-02-04 03:09:53 +0000668Standard library
669
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000670- pyexpat now detects the expat version if expat.h defines it. A
671 number of additional handlers are provided, which are only available
672 since expat 1.95. In addition, the methods SetParamEntityParsing and
673 GetInputContext of Parser objects are available with 1.95.x
674 only. Parser objects now provide the ordered_attributes and
675 specified_attributes attributes. A new module expat.model was added,
676 which offers a number of additional constants if 1.95.x is used.
677
678- xml.dom offers the new functions registerDOMImplementation and
679 getDOMImplementation.
680
681- xml.dom.minidom offers a toprettyxml method. A number of DOM
682 conformance issues have been resolved. In particular, Element now
683 has an hasAttributes method, and the handling of namespaces was
684 improved.
685
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000686- Ka-Ping Yee contributed two new modules: inspect.py, a module for
687 getting information about live Python code, and pydoc.py, a module
688 for interactively converting docstrings to HTML or text.
689 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +0000690 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +0000691 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
692 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000693
Tim Peters1eff7962001-03-01 02:31:33 +0000694- New library module difflib.py, primarily packaging the SequenceMatcher
695 class at the heart of the popular ndiff.py file-comparison tool.
696
697- doctest.py (a framework for verifying Python code examples in docstrings)
698 is now part of the std library.
699
Tim Petersd66595f2001-02-04 03:09:53 +0000700Windows changes
701
Guido van Rossume3955a82001-03-02 14:05:59 +0000702- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
703 small GUI that lets you browse the module docstrings using your
704 default web browser.
705
Tim Peters1eff7962001-03-01 02:31:33 +0000706- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
707 Platforms) is implemented. See
708
709 http://python.sourceforge.net/peps/pep-0235.html
710
711 for full details, especially the "Current Lower-Left Semantics" section.
712 The new Windows import rules are simpler than before:
713
714 A. If the PYTHONCASEOK environment variable exists, same as
715 before: silently accept the first case-insensitive match of any
716 kind; raise ImportError if none found.
717
718 B. Else search sys.path for the first case-sensitive match; raise
719 ImportError if none found.
720
721 The same rules have been implented on other platforms with case-
722 insensitive but case-preserving filesystems too (including Cygwin, and
723 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +0000724
Tim Peters25a9ce32001-02-19 07:06:36 +0000725- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
726 what it's supposed to do (and does do under NT and 2000) via direct
727 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +0000728 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +0000729 all Win9x systems before.
730
Tim Peters1eff7962001-03-01 02:31:33 +0000731- Build: Subproject _test (effectively) renamed to _testcapi.
732
Tim Peters2fe289a2001-03-01 22:19:38 +0000733New platforms
734
735- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
736 Thanks to Steven Majewski!
737
738- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
739 Tishler!
740
Guido van Rossum9089b272001-03-02 06:49:50 +0000741- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
742 Schwertberger! See RISCOS/README for more information -- it seems
743 that because of the bizarre filename conventions on RISCOS, no port
744 to that platform is easy. Note that the new variable os.endsep is
745 silently supported in order to make life easier on this platform,
746 but we don't advertise it because it's not worth for most folks to
747 care about RISCOS portability.
748
Tim Peters25a9ce32001-02-19 07:06:36 +0000749
Tim Petersd7b5e882001-01-25 03:36:26 +0000750What's New in Python 2.1 alpha 2?
751=================================
Tim Peters40ead762001-01-27 05:35:26 +0000752
Tim Petersd7b5e882001-01-25 03:36:26 +0000753Core language, builtins, and interpreter
754
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000755- Scopes nest. If a name is used in a function or class, but is not
756 local, the definition in the nearest enclosing function scope will
757 be used. One consequence of this change is that lambda statements
758 could reference variables in the namespaces where the lambda is
759 defined. In some unusual cases, this change will break code.
760
761 In all previous version of Python, names were resolved in exactly
762 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000763 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000764 function A is defined within a function B, the names bound in B are
765 not visible in A. The new rules make names bound in B visible in A,
766 unless A contains a name binding that hides the binding in B.
767
768 Section 4.1 of the reference manual describes the new scoping rules
769 in detail. The test script in Lib/test/test_scope.py demonstrates
770 some of the effects of the change.
771
772 The new rules will cause existing code to break if it defines nested
773 functions where an outer function has local variables with the same
774 name as globals or builtins used by the inner function. Example:
775
776 def munge(str):
777 def helper(x):
778 return str(x)
779 if type(str) != type(''):
780 str = helper(str)
781 return str.strip()
782
783 Under the old rules, the name str in helper() is bound to the
784 builtin function str(). Under the new rules, it will be bound to
785 the argument named str and an error will occur when helper() is
786 called.
787
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000788- The compiler will report a SyntaxError if "from ... import *" occurs
789 in a function or class scope. The language reference has documented
790 that this case is illegal, but the compiler never checked for it.
791 The recent introduction of nested scope makes the meaning of this
792 form of name binding ambiguous. In a future release, the compiler
793 may allow this form when there is no possibility of ambiguity.
794
Tim Peters40ead762001-01-27 05:35:26 +0000795- repr(string) is easier to read, now using hex escapes instead of octal,
796 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
797
798 >>> "\texample \r\n" + chr(0) + chr(255)
799 '\texample \r\n\x00\xff' # in 2.1
800 '\011example \015\012\000\377' # in 2.0
801
Moshe Zadka6af0ce02001-01-29 06:41:00 +0000802- Functions are now compared and hashed by identity, not by value, since
803 the func_code attribute is writable.
804
Fred Drakefb9d7122001-02-01 20:00:40 +0000805- Weak references (PEP 205) have been added. This involves a few
806 changes in the core, an extension module (_weakref), and a Python
807 module (weakref). The weakref module is the public interface. It
808 includes support for "explicit" weak references, proxy objects, and
809 mappings with weakly held values.
810
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000811- A 'continue' statement can now appear in a try block within the body
812 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +0000813 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000814
Tim Petersd7b5e882001-01-25 03:36:26 +0000815Standard library
816
Barry Warsaw30dbd142001-01-31 22:14:01 +0000817- mailbox.py now has a new class, PortableUnixMailbox which is
818 identical to UnixMailbox but uses a more portable scheme for
819 determining From_ separators. Also, the constructors for all the
820 classes in this module have a new optional `factory' argument, which
821 is a callable used when new message classes must be instantiated by
822 the next() method.
823
Tim Petersd7b5e882001-01-25 03:36:26 +0000824- random.py is now self-contained, and offers all the functionality of
825 the now-deprecated whrandom.py. See the docs for details. random.py
826 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +0000827 and restoring the internal state of the generator; and jumpahead(n),
828 for quickly forcing the internal state to be the same as if n calls to
829 random() had been made. The latter is particularly useful for multi-
830 threaded programs, creating one instance of the random.Random() class for
831 each thread, then using .jumpahead() to force each instance to use a
832 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +0000833
Tim Peters0de88fc2001-02-01 04:59:18 +0000834- random.py's seed() function is new. For bit-for-bit compatibility with
835 prior releases, use the whseed function instead. The new seed function
836 addresses two problems: (1) The old function couldn't produce more than
837 about 2**24 distinct internal states; the new one about 2**45 (the best
838 that can be done in the Wichmann-Hill generator). (2) The old function
839 sometimes produced identical internal states when passed distinct
840 integers, and there was no simple way to predict when that would happen;
841 the new one guarantees to produce distinct internal states for all
842 arguments in [0, 27814431486576L).
843
Jeremy Hylton4c4fda02001-02-02 03:29:24 +0000844- The socket module now supports raw packets on Linux. The socket
845 family is AF_PACKET.
846
Tim Peters9ea17ac2001-02-02 05:57:15 +0000847- test_capi.py is a start at running tests of the Python C API. The tests
848 are implemented by the new Modules/_testmodule.c.
849
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000850- A new extension module, _symtable, provides provisional access to the
851 internal symbol table used by the Python compiler. A higher-level
852 interface will be added on top of _symtable in a future release.
853
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +0000854- Removed the obsolete soundex module.
855
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000856- xml.dom.minidom now uses the standard DOM exceptions. Node supports
857 the isSameNode method; NamedNodeMap the get method.
858
859- xml.sax.expatreader supports the lexical handler property; it
860 generates comment, startCDATA, and endCDATA events.
861
Tim Petersee826f82001-01-31 19:39:44 +0000862Windows changes
863
864- Build procedure: the zlib project is built in a different way that
865 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +0000866 the zlib binary used. See PCbuild\readme.txt for details. Your old
867 zlib-related directories can be deleted; you'll need to download fresh
868 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +0000869
Tim Peters9ea17ac2001-02-02 05:57:15 +0000870- Build: New subproject _test for the benefit of test_capi.py (see above).
871
Tim Petersb16c56f2001-02-02 21:24:51 +0000872- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
873 interface to some Python compiler internals).
874
875- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +0000876 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +0000877
Tim Petersa3a3a032000-11-30 05:22:44 +0000878What's New in Python 2.1 alpha 1?
879=================================
880
881Core language, builtins, and interpreter
882
Marc-André Lemburgebb195b2001-01-20 10:34:52 +0000883- There is a new Unicode companion to the PyObject_Str() API
884 called PyObject_Unicode(). It behaves in the same way as the
885 former, but assures that the returned value is an Unicode object
886 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +0000887
Guido van Rossumf98eda02001-01-17 15:54:45 +0000888- The comparison operators support "rich comparison overloading" (PEP
889 207). C extension types can provide a rich comparison function in
890 the new tp_richcompare slot in the type object. The cmp() function
891 and the C function PyObject_Compare() first try the new rich
892 comparison operators before trying the old 3-way comparison. There
893 is also a new C API PyObject_RichCompare() (which also falls back on
894 the old 3-way comparison, but does not constrain the outcome of the
895 rich comparison to a Boolean result).
896
897 The rich comparison function takes two objects (at least one of
898 which is guaranteed to have the type that provided the function) and
899 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
900 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
901 object, which may be NotImplemented (in which case the tp_compare
902 slot function is used as a fallback, if defined).
903
904 Classes can overload individual comparison operators by defining one
905 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +0000906 __ge__. There are no explicit "reflected argument" versions of
907 these; instead, __lt__ and __gt__ are each other's reflection,
908 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
909 reflection (similar at the C level). No other implications are
910 made; in particular, Python does not assume that == is the Boolean
911 inverse of !=, or that < is the Boolean inverse of >=. This makes
912 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +0000913
914 Classes or types that want to implement (in)equality tests but not
915 the ordering operators (i.e. unordered types) should implement ==
916 and !=, and raise an error for the ordering operators.
917
Guido van Rossuma88479f2001-01-18 14:28:08 +0000918 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +0000919 Boolean; e.g. a matrix type might want to return a matrix of bits
920 for A < B, giving elementwise comparisons. Such types should ensure
921 that any interpretation of their value in a Boolean context raises
922 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
923 at the C level) to always raise an exception.
924
Guido van Rossuma88479f2001-01-18 14:28:08 +0000925- Complex numbers use rich comparisons to define == and != but raise
926 an exception for <, <=, > and >=. Unfortunately, this also means
927 that cmp() of two complex numbers raises an exception when the two
928 numbers differ. Since it is not mathematically meaningful to compare
929 complex numbers except for equality, I hope that this doesn't break
930 too much code.
931
Tim Peters3389f192001-02-18 08:48:49 +0000932- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +0000933 not defined by the language, other than that it's arbitrary but
934 consistent (see the Reference Manual). An implementation detail changed
935 in 2.1a1 such that None now compares less than any other object. Code
936 relying on this new behavior (like code that relied on the previous
937 behavior) does so at its own risk.
938
Barry Warsaw573b5412001-01-15 20:43:18 +0000939- Functions and methods now support getting and setting arbitrarily
940 named attributes (PEP 232). Functions have a new __dict__
941 (a.k.a. func_dict) which hold the function attributes. Methods get
942 and set attributes on their underlying im_func. It is a TypeError
943 to set an attribute on a bound method.
944
Guido van Rossum051e3352001-01-15 19:11:10 +0000945- The xrange() object implementation has been improved so that
946 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
947 limitation that in this case len(xrange(sys.maxint)) can't be
948 calculated, but the common idiom "for i in xrange(sys.maxint)" will
949 work fine as long as the index i doesn't actually reach 2**31.
950 (Python uses regular ints for sequence and string indices; fixing
951 that is much more work.)
952
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000953- Two changes to from...import:
954
Guido van Rossumba381232001-02-03 15:06:40 +0000955 1) "from M import X" now works even if (after loading module M)
956 sys.modules['M'] is not a real module; it's basically a getattr()
957 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000958
959 2) "from M import *" now looks for M.__all__ to decide which names to
960 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
961 filters out names starting with '_' as before. Whether or not
962 __all__ exists, there's no restriction on the type of M.
963
Guido van Rossumf61f1662001-01-10 20:13:55 +0000964- File objects have a new method, xreadlines(). This is the fastest
965 way to iterate over all lines in a file:
966
967 for line in file.xreadlines():
968 ...do something to line...
969
970 See the xreadlines module (mentioned below) for how to do this for
971 other file-like objects.
972
973- Even if you don't use file.xreadlines(), you may expect a speedup on
974 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +0000975 quite a bit in platform-specific ways: on systems (like Linux) that
976 support flockfile(), getc_unlocked(), and funlockfile(), those are
977 used by default. On systems (like Windows) without getc_unlocked(),
978 a complicated (but still thread-safe) method using fgets() is used by
979 default.
980
Tim Petersd52269b2001-01-25 06:23:18 +0000981 You can force use of the fgets() method by #define'ing
982 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +0000983 getc_unlocked()).
984
Tim Petersd52269b2001-01-25 06:23:18 +0000985 You can force fgets() not to be used by #define'ing
986 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +0000987 test_bufio.py fails -- and let us know if it does!).
988
989- In addition, the fileinput module, while still slower than the other
990 methods on most platforms, has been sped up too, by using
991 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +0000992
993- Support for run-time warnings has been added, including a new
994 command line option (-W) to specify the disposition of warnings.
995 See the description of the warnings module below.
996
997- Extensive changes have been made to the coercion code. This mostly
998 affects extension modules (which can now implement mixed-type
999 numerical operators without having to use coercion), but
1000 occasionally, in boundary cases the coercion semantics have changed
1001 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001002 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001003 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001004 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001005
Guido van Rossumf98eda02001-01-17 15:54:45 +00001006- In connection with the coercion changes, a new built-in singleton
1007 object, NotImplemented is defined. This can be returned for
1008 operations that wish to indicate they are not implemented for a
1009 particular combination of arguments. From C, this is
1010 Py_NotImplemented.
1011
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001012- The interpreter accepts now bytecode files on the command line even
1013 if they do not have a .pyc or .pyo extension. On Linux, after executing
1014
Martin v. Löwise214baa2001-02-04 22:37:56 +00001015import imp,sys,string
1016magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1017reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1018open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001019
1020 any byte code file can be used as an executable (i.e. as an argument
1021 to execve(2)).
1022
Tim Peters9940b802000-12-01 07:59:35 +00001023- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001024 character. In 1.6 and earlier, they never produced a sign,
1025 and raised an error if the value of the long was too large
1026 to fit in a Python int. In 2.0, they produced a sign if and
1027 only if too large to fit in an int. This was inconsistent
1028 across platforms (because the size of an int varies across
1029 platforms), and inconsistent with hex() and oct(). Example:
1030
1031 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001032 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001033 'ffffffbe' # in 2.0 and before, on 32-bit machines
1034 >>> hex(-0x42L)
1035 '-0x42L' # in all versions of Python
1036
Tim Peters9940b802000-12-01 07:59:35 +00001037 The behavior of %d formats for negative Python longs remains
1038 the same as in 2.0 (although in 1.6 and before, they raised
1039 an error if the long didn't fit in a Python int).
1040
1041 %u formats don't make sense for Python longs, but are allowed
1042 and treated the same as %d in 2.1. In 2.0, a negative long
1043 formatted via %u produced a sign if and only if too large to
1044 fit in an int. In 1.6 and earlier, a negative long formatted
1045 via %u raised an error if it was too big to fit in an int.
1046
Guido van Rossum3661d392000-12-12 22:10:31 +00001047- Dictionary objects have an odd new method, popitem(). This removes
1048 an arbitrary item from the dictionary and returns it (in the form of
1049 a (key, value) pair). This can be useful for algorithms that use a
1050 dictionary as a bag of "to do" items and repeatedly need to pick one
1051 item. Such algorithms normally end up running in quadratic time;
1052 using popitem() they can usually be made to run in linear time.
1053
Tim Peters36cdad12000-12-29 02:06:45 +00001054Standard library
1055
Thomas Woutersfe385252001-01-19 23:16:56 +00001056- In the time module, the time argument to the functions strftime,
1057 localtime, gmtime, asctime and ctime is now optional, defaulting to
1058 the current time (in the local timezone).
1059
Guido van Rossumda91f222001-01-15 16:36:08 +00001060- The ftplib module now defaults to passive mode, which is deemed a
1061 more useful default given that clients are often inside firewalls
1062 these days. Note that this could break if ftplib is used to connect
1063 to a *server* that is inside a firewall, from outside; this is
1064 expected to be a very rare situation. To fix that, you can call
1065 ftp.set_pasv(0).
1066
Martin v. Löwis10a27872001-01-13 09:54:41 +00001067- The module site now treats .pth files not only for path configuration,
1068 but also supports extensions to the initialization code: Lines starting
1069 with import are executed.
1070
Guido van Rossumf61f1662001-01-10 20:13:55 +00001071- There's a new module, warnings, which implements a mechanism for
1072 issuing and filtering warnings. There are some new built-in
1073 exceptions that serve as warning categories, and a new command line
1074 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1075 turns warnings into errors). warnings.warn(message[, category])
1076 issues a warning message; this can also be called from C as
1077 PyErr_Warn(category, message).
1078
1079- A new module xreadlines was added. This exports a single factory
1080 function, xreadlines(). The intention is that this code is the
1081 absolutely fastest way to iterate over all lines in an open
1082 file(-like) object:
1083
1084 import xreadlines
1085 for line in xreadlines.xreadlines(file):
1086 ...do something to line...
1087
1088 This is equivalent to the previous the speed record holder using
1089 file.readlines(sizehint). Note that if file is a real file object
1090 (as opposed to a file-like object), this is equivalent:
1091
1092 for line in file.xreadlines():
1093 ...do something to line...
1094
Tim Peters36cdad12000-12-29 02:06:45 +00001095- The bisect module has new functions bisect_left, insort_left,
1096 bisect_right and insort_right. The old names bisect and insort
1097 are now aliases for bisect_right and insort_right. XXX_right
1098 and XXX_left methods differ in what happens when the new element
1099 compares equal to one or more elements already in the list: the
1100 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001101 right. Code that doesn't care where equal elements end up should
1102 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001103
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001104- The new curses.panel module wraps the panel library that forms part
1105 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1106
Guido van Rossumf61f1662001-01-10 20:13:55 +00001107- The SocketServer module now sets the allow_reuse_address flag by
1108 default in the TCPServer class.
1109
1110- A new function, sys._getframe(), returns the stack frame pointer of
1111 the caller. This is intended only as a building block for
1112 higher-level mechanisms such as string interpolation.
1113
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001114- The pyexpat module supports a number of new handlers, which are
1115 available only in expat 1.2. If invocation of a callback fails, it
1116 will report an additional frame in the traceback. Parser objects
1117 participate now in garbage collection. If expat reports an unknown
1118 encoding, pyexpat will try to use a Python codec; that works only
1119 for single-byte charsets. The parser type objects is exposed as
1120 XMLParserObject.
1121
1122- xml.dom now offers standard definitions for symbolic node type and
1123 exception code constants, and a hierarchy of DOM exceptions. minidom
1124 was adjusted to use them.
1125
1126- The conformance of xml.dom.minidom to the DOM specification was
1127 improved. It detects a number of additional error cases; the
1128 previous/next relationship works even when the tree is modified;
1129 Node supports the normalize() method; NamedNodeMap, DocumentType and
1130 DOMImplementation classes were added; Element supports the
1131 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1132 method.
1133
Guido van Rossumf61f1662001-01-10 20:13:55 +00001134Build issues
1135
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001136- For Unix (and Unix-compatible) builds, configuration and building of
1137 extension modules is now greatly automated. Rather than having to
1138 edit the Modules/Setup file to indicate which modules should be
1139 built and where their include files and libraries are, a
1140 distutils-based setup.py script now takes care of building most
1141 extension modules. All extension modules built this way are built
1142 as shared libraries. Only a few modules that must be linked
1143 statically are still listed in the Setup file; you won't need to
1144 edit their configuration.
1145
1146- Python should now build out of the box on Cygwin. If it doesn't,
1147 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001148
1149- Python now always uses its own (renamed) implementation of getopt()
1150 -- there's too much variation among C library getopt()
1151 implementations.
1152
1153- C++ compilers are better supported; the CXX macro is always set to a
1154 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001155
Tim Petersd92dfe02000-12-12 01:18:41 +00001156Windows changes
1157
1158- select module: By default under Windows, a select() call
1159 can specify no more than 64 sockets. Python now boosts
1160 this Microsoft default to 512. If you need even more than
1161 that, see the MS docs (you'll need to #define FD_SETSIZE
1162 and recompile Python from source).
1163
Guido van Rossumf61f1662001-01-10 20:13:55 +00001164- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1165 subdirectory is no more!
1166
Tim Petersa3a3a032000-11-30 05:22:44 +00001167
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001168What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001169=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001170
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001171Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001172changes are in the file HISTORY. If you are making the jump directly
1173from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1174HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001175
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001176Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1177the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1178http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001179
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001180--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001181
1182======================================================================
1183
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001184What's new in 2.0 (since release candidate 1)?
1185==============================================
1186
1187Standard library
1188
1189- The copy_reg module was modified to clarify its intended use: to
1190 register pickle support for extension types, not for classes.
1191 pickle() will raise a TypeError if it is passed a class.
1192
1193- Fixed a bug in gettext's "normalize and expand" code that prevented
1194 it from finding an existing .mo file.
1195
1196- Restored support for HTTP/0.9 servers in httplib.
1197
Tim Peters989b7b92000-10-16 20:24:53 +00001198- The math module was changed to stop raising OverflowError in case of
1199 underflow, and return 0 instead in underflow cases. Whether Python
1200 used to raise OverflowError in case of underflow was platform-
1201 dependent (it did when the platform math library set errno to ERANGE
1202 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001203
1204- Fixed a bug in StringIO that occurred when the file position was not
1205 at the end of the file and write() was called with enough data to
1206 extend past the end of the file.
1207
1208- Fixed a bug that caused Tkinter error messages to get lost on
1209 Windows. The bug was fixed by replacing direct use of
1210 interp->result with Tcl_GetStringResult(interp).
1211
1212- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1213 redirect response.
1214
1215- Several changes were made to distutils: Some debugging code was
1216 removed from util. Fixed the installer used when an external zip
1217 program (like WinZip) is not found; the source code for this
1218 installer is in Misc/distutils. check_lib() was modified to behave
1219 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1220 test for whether installed modules are on sys.path was changed to
1221 use both normcase() and normpath().
1222
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001223- Several minor bugs were fixed in the xml package (the minidom,
1224 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001225
1226- The regression test driver (regrtest.py) behavior when invoked with
1227 -l changed: It now reports a count of objects that are recognized as
1228 garbage but not freed by the garbage collector.
1229
Tim Peters989b7b92000-10-16 20:24:53 +00001230- The regression test for the math module was changed to test
1231 exceptional behavior when the test is run in verbose mode. Python
1232 cannot yet guarantee consistent exception behavior across platforms,
1233 so the exception part of test_math is run only in verbose mode, and
1234 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001235
1236Internals
1237
1238- PyOS_CheckStack() has been disabled on Win64, where it caused
1239 test_sre to fail.
1240
1241Build issues
1242
1243- Changed compiler flags, so that gcc is always invoked with -Wall and
1244 -Wstrict-prototypes. Users compiling Python with GCC should see
1245 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001246 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001247 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001248
Tim Petersa3a3a032000-11-30 05:22:44 +00001249- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001250
1251Tools and other miscellany
1252
1253- The compiler in Tools/compiler was updated to support the new
1254 language features introduced in 2.0: extended print statement, list
1255 comprehensions, and augmented assignments. The new compiler should
1256 also be backwards compatible with Python 1.5.2; the compiler will
1257 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001258 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001259
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001260What's new in 2.0 release candidate 1 (since beta 2)?
1261=====================================================
1262
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001263What is release candidate 1?
1264
1265We believe that release candidate 1 will fix all known bugs that we
1266intend to fix for the 2.0 final release. This release should be a bit
1267more stable than the previous betas. We would like to see even more
1268widespread testing before the final release, so we are producing this
1269release candidate. The final release will be exactly the same unless
1270any show-stopping (or brown bag) bugs are found by testers of the
1271release candidate.
1272
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001273All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001274to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001275
1276Core language, builtins, and interpreter
1277
1278- A bug that caused crashes when __coerce__ was used with augmented
1279 assignment, e.g. +=, was fixed.
1280
1281- Raise ZeroDivisionError when raising zero to a negative number,
1282 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1283 power operator and the result of math.pow(0.0, -2.0) will vary by
1284 platform. On Linux, it raises a ValueError.
1285
1286- A bug in Unicode string interpolation was fixed that occasionally
1287 caused errors with formats including "%%". For example, the
1288 following expression "%% %s" % u"abc" no longer raises a TypeError.
1289
1290- Compilation of deeply nested expressions raises MemoryError instead
1291 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1292
1293- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1294 rendering them useless. They are now written in binary mode again.
1295
1296Standard library
1297
1298- Keyword arguments are now accepted for most pattern and match object
1299 methods in SRE, the standard regular expression engine.
1300
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001301- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001302 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001303
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001304- Several bugs in the Unicode handling and error handling in _tkinter
1305 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001306
1307- Fix memory management errors in Merge() and Tkapp_Call() routines.
1308
1309- Several changes were made to cStringIO to make it compatible with
1310 the file-like object interface and with StringIO. If operations are
1311 performed on a closed object, an exception is raised. The truncate
1312 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001313 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001314
1315- There were many changes made to the linuxaudiodev module and its
1316 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001317 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001318
1319 Note that this module is named poorly, because it should work
1320 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001321 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001322
1323 The module now raises exceptions when errors occur instead of
1324 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1325 audio) and defines a getptr() method that calls the
1326 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1327
1328- The library_version attribute, introduced in an earlier beta, was
1329 removed because it can not be supported with early versions of the C
1330 readline library, which provides no way to determine the version at
1331 compile-time.
1332
1333- The binascii module is now enabled on Win64.
1334
Tim Peters46446d62000-10-09 21:19:31 +00001335- tokenize.py no longer suffers "recursion depth" errors when parsing
1336 programs with very long string literals.
1337
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001338Internals
1339
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001340- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001341 which is called when the interpreter starts up to determine where
1342 the standard library is installed. These vulnerabilities affect all
1343 previous versions of Python and can be exploited by setting very
1344 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1345 setuid Python script, although use of the wrapper in
1346 Misc/setuid-prog.c will eliminate the vulnerability.
1347
1348- Fixed garbage collection bugs in instance creation that were
1349 triggered when errors occurred during initialization. The solution,
1350 applied in cPickle and in PyInstance_New(), is to call
1351 PyObject_GC_Init() after the initialization of the object's
1352 container attributes is complete.
1353
1354- pyexpat adds definitions of PyModule_AddStringConstant and
1355 PyModule_AddObject if the Python version is less than 2.0, which
1356 provides compatibility with PyXML on Python 1.5.2.
1357
1358- If the platform has a bogus definition for LONG_BIT (the number of
1359 bits in a long), an error will be reported at compile time.
1360
1361- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1362 collection crashes and possibly other, unreported crashes.
1363
1364- Fixed a memory leak in _PyUnicode_Fini().
1365
1366Build issues
1367
1368- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001369 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001370 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001371
1372- The mmap.PAGESIZE constant is now initialized using sysconf when
1373 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1374
1375- The md5 file should now compile on all platforms.
1376
1377- The select module now compiles on platforms that do not define
1378 POLLRDNORM and related constants.
1379
1380- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001381 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001382
Jeremy Hylton10921202000-10-09 18:34:12 +00001383- BeOS: A number of changes were made to the build and installation
1384 process. ar-fake now operates on a directory of object files.
1385 dl_export.h is gone, and its macros now appear on the mwcc command
1386 line during build on PPC BeOS.
1387
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001388- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001389 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001390
1391- Cygwin: Support for shared libraries, Tkinter, and sockets.
1392
1393- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1394
1395Tools and other miscellany
1396
1397- Removed debugging prints from main used with freeze.
1398
Tim Peters46446d62000-10-09 21:19:31 +00001399- IDLE auto-indent no longer crashes when it encounters Unicode
1400 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001401
1402What's new in 2.0 beta 2 (since beta 1)?
1403========================================
1404
1405Core language, builtins, and interpreter
1406
Tim Peters482c0212000-09-26 06:33:09 +00001407- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001408 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001409
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001410- Add -h and -V command line options to print the usage message and
1411 Python version number and exit immediately.
1412
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001413- eval() and exec accept Unicode objects as code parameters.
1414
1415- getattr() and setattr() now also accept Unicode objects for the
1416 attribute name, which are converted to strings using the default
1417 encoding before lookup.
1418
1419- Multiplication on string and Unicode now does proper bounds
1420 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1421 string is too long."
1422
1423- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001424 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001425
Jeremy Hylton1b618592000-09-26 05:32:36 +00001426
1427Standard library and extensions
1428
Guido van Rossum5b08f132001-04-16 02:05:23 +00001429- socket module: the OpenSSL code now adds support for RAND_status()
1430 and EGD (Entropy Gathering Device).
1431
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001432- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001433 argument checking; it still takes no arguments.
1434
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001435- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001436
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001437- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001438
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001439- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001440
1441- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001442 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001443
1444- copy: Copy Unicode objects atomically.
1445
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001446- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001447
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001448- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001449
Fred Drake67233bc2000-09-26 16:40:27 +00001450- dbm: Add get() and setdefault() methods to dbm object. Add constant
1451 `library' to module that names the library used. Added doc strings
1452 and method names to error messages. Uses configure to determine
1453 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
1454 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001455
1456- distutils: Update to version 0.9.3.
1457
1458- dl: Add several dl.RTLD_ constants.
1459
1460- fpectl: Now supported on FreeBSD.
1461
1462- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
1463 found by the collector will be saved in gc.garbage. This is useful
1464 for debugging a program that creates reference cycles.
1465
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001466- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00001467 of HTTP class. Do not close socket on zero-length response. Do not
1468 crash when server sends invalid content-length header.
1469
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001470- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001471
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001472- marshal: When reading a short, sign-extend on platforms where shorts
1473 are bigger than 16 bits. When reading a long, repair the unportable
1474 sign extension that was being done for 64-bit machines. (It assumed
1475 that signed right shift sign-extends.)
1476
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001477- operator: Add contains(), invert(), __invert__() as aliases for
1478 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001479
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001480- os: Add support for popen2() and popen3() on all platforms where
1481 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001482
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001483- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00001484 clicking on a file in Explorer (or passing the file name to the
1485 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001486
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001487- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00001488 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001489
1490- pickle: Now raises ValueError when an invalid pickle that contains
1491 a non-string repr where a string repr was expected. This behavior
1492 matches cPickle.
1493
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001494- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001495
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001496- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001497
1498- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001499 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001500 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001501
1502- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001503 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001504
1505- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00001506 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00001507 few cycles during startup since the first call to
1508 setdefaultencoding() will initialize the codec registry and the
1509 encodings package.
1510
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001511- socket: Support for size hint in readlines() method of object returned
1512 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001513
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001514- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001515 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001516 is followed by whitespace.
1517
Tim Petersa3a3a032000-11-30 05:22:44 +00001518- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001519
1520- struct: Check ranges for bytes and shorts.
1521
1522- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001523 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001524
1525- Tkinter: Image objects are now guaranteed to have unique ids. Set
1526 event.delta to zero if Tk version doesn't support mousewheel.
1527 Removed some debugging prints.
1528
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001529- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001530
Fred Drake67233bc2000-09-26 16:40:27 +00001531- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001532 which works around a bug in Norton AntiVirus 2000 that leads directly
1533 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001534
1535- xml: New version detection code allows PyXML to override standard
1536 XML package if PyXML version is greater than 0.6.1.
1537
Fred Drake64bb3802000-09-26 16:21:35 +00001538- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
1539 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
1540 tree only for nodes which are sufficiently interesting to a specific
1541 application. Does not provide the HTML-specific extensions. Still
1542 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001543
Fred Drake64bb3802000-09-26 16:21:35 +00001544- xml.sax: SAX 2 support for Python, including all the handler
1545 interfaces needed to process XML 1.0 compliant XML. Some
1546 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001547
Fred Drake64bb3802000-09-26 16:21:35 +00001548- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
1549 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001550
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001551
Jeremy Hylton1b618592000-09-26 05:32:36 +00001552C API
1553
1554- Add three new convenience functions for module initialization --
1555 PyModule_AddObject(), PyModule_AddIntConstant(), and
1556 PyModule_AddStringConstant().
1557
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001558- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00001559 removed and add #error to Python.h if NULL isn't defined after
1560 #include of stdio.h.
1561
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001562- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00001563 backwards compatibility (at the source level) with old extensions.
1564
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001565- A wrapper API was added for signal() and sigaction(). Instead of
1566 either function, always use PyOS_getsig() to get a signal handler
1567 and PyOS_setsig() to set one. A new convenience typedef
1568 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001569
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001570- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00001571 internal data buffer and size of a string object -- or the default
1572 encoded version of a Unicode object.
1573
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001574- PyString_Size() and PyString_AsString() accept Unicode objects.
1575
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001576- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00001577 exists). INT_MAX and LONG_MAX will always be defined, even if
1578 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001579
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001580- PyFloat_FromString takes a second argument, pend, that was
1581 effectively useless. It is now officially useless but preserved for
1582 backwards compatibility. If the pend argument is not NULL, *pend is
1583 set to NULL.
1584
1585- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
1586 for the attribute name. See note on getattr() above.
1587
1588- A few bug fixes to argument processing for Unicode.
1589 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
1590 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
1591 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00001592 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001593
1594- Py_BuildValue accepts B format (for bgen-generated code).
1595
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001596
Jeremy Hylton1b618592000-09-26 05:32:36 +00001597Internals
1598
1599- On Unix, fix code for finding Python installation directory so that
1600 it works when argv[0] is a relative path.
1601
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00001602- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001603 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00001604 rather than by generating a copy of the object.
1605
Tim Peters482c0212000-09-26 06:33:09 +00001606- Several of the internal Unicode tables are much smaller now, and
1607 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001608
Jeremy Hylton97693b02000-09-26 17:42:51 +00001609- In the garbage collector: Fixed bug in collection of tuples. Fixed
1610 bug that caused some instances to be removed from the container set
1611 while they were still live. Fixed parsing in gc.set_debug() for
1612 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001613
1614- Fixed refcount problem in instance deallocation that only occurred
1615 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
1616
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001617- On Windows, getpythonregpath is now protected against null data in
1618 registry key.
1619
1620- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00001621 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001622
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001623
Jeremy Hylton1b618592000-09-26 05:32:36 +00001624Build and platform-specific issues
1625
1626- Better support of GNU Pth via --with-pth configure option.
1627
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001628- Python/C API now properly exposed to dynamically-loaded extension
1629 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001630
1631- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
1632 Don't define MS_SYNC to be zero when it is undefined. Added missing
1633 prototypes in posixmodule.c.
1634
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001635- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001636 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001637
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001638- Fix largefile support on older NetBSD systems and OpenBSD by adding
1639 define for TELL64.
1640
1641
1642Tools and other miscellany
1643
1644- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
1645
1646- freeze: The modulefinder now works with 2.0 opcodes.
1647
Tim Petersa3a3a032000-11-30 05:22:44 +00001648- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001649 Move hackery of sys.argv until after the Tk instance has been
1650 created, which allows the application-specific Tkinter
1651 initialization to be executed if present; also pass an explicit
1652 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00001653
Jeremy Hylton1b618592000-09-26 05:32:36 +00001654
1655What's new in 2.0 beta 1?
1656=========================
1657
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001658Source Incompatibilities
1659------------------------
1660
1661None. Note that 1.6 introduced several incompatibilities with 1.5.2,
1662such as single-argument append(), connect() and bind(), and changes to
1663str(long) and repr(float).
1664
1665
1666Binary Incompatibilities
1667------------------------
1668
1669- Third party extensions built for Python 1.5.x or 1.6 cannot be used
1670with Python 2.0; these extensions will have to be rebuilt for Python
16712.0.
1672
1673- On Windows, attempting to import a third party extension built for
1674Python 1.5.x or 1.6 results in an immediate crash; there's not much we
1675can do about this. Check your PYTHONPATH environment variable!
1676
1677- Python bytecode files (*.pyc and *.pyo) are not compatible between
1678releases.
1679
1680
1681Overview of Changes Since 1.6
1682-----------------------------
1683
1684There are many new modules (including brand new XML support through
1685the xml package, and i18n support through the gettext module); a list
1686of all new modules is included below. Lots of bugs have been fixed.
1687
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001688The process for making major new changes to the language has changed
1689since Python 1.6. Enhancements must now be documented by a Python
1690Enhancement Proposal (PEP) before they can be accepted.
1691
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001692There are several important syntax enhancements, described in more
1693detail below:
1694
1695 - Augmented assignment, e.g. x += 1
1696
1697 - List comprehensions, e.g. [x**2 for x in range(10)]
1698
1699 - Extended import statement, e.g. import Module as Name
1700
1701 - Extended print statement, e.g. print >> file, "Hello"
1702
1703Other important changes:
1704
1705 - Optional collection of cyclical garbage
1706
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001707Python Enhancement Proposal (PEP)
1708---------------------------------
1709
1710PEP stands for Python Enhancement Proposal. A PEP is a design
1711document providing information to the Python community, or describing
1712a new feature for Python. The PEP should provide a concise technical
1713specification of the feature and a rationale for the feature.
1714
1715We intend PEPs to be the primary mechanisms for proposing new
1716features, for collecting community input on an issue, and for
1717documenting the design decisions that have gone into Python. The PEP
1718author is responsible for building consensus within the community and
1719documenting dissenting opinions.
1720
1721The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001722
1723Augmented Assignment
1724--------------------
1725
1726This must have been the most-requested feature of the past years!
1727Eleven new assignment operators were added:
1728
Guido van Rossume905e952000-09-05 12:42:46 +00001729 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001730
1731For example,
1732
1733 A += B
1734
1735is similar to
1736
1737 A = A + B
1738
1739except that A is evaluated only once (relevant when A is something
1740like dict[index].attr).
1741
1742However, if A is a mutable object, A may be modified in place. Thus,
1743if A is a number or a string, A += B has the same effect as A = A+B
1744(except A is only evaluated once); but if a is a list, A += B has the
1745same effect as A.extend(B)!
1746
1747Classes and built-in object types can override the new operators in
1748order to implement the in-place behavior; the not-in-place behavior is
1749used automatically as a fallback when an object doesn't implement the
1750in-place behavior. For classes, the method name is derived from the
1751method name for the corresponding not-in-place operator by inserting
1752an 'i' in front of the name, e.g. __iadd__ implements in-place
1753__add__.
1754
1755Augmented assignment was implemented by Thomas Wouters.
1756
1757
1758List Comprehensions
1759-------------------
1760
1761This is a flexible new notation for lists whose elements are computed
1762from another list (or lists). The simplest form is:
1763
1764 [<expression> for <variable> in <sequence>]
1765
Guido van Rossum56db0952000-09-06 23:34:25 +00001766For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001767This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001768
1769You can also add a condition:
1770
1771 [<expression> for <variable> in <sequence> if <condition>]
1772
1773For example, [w for w in words if w == w.lower()] would yield the list
1774of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001775than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001776
1777You can also have nested for loops and more than one 'if' clause. For
1778example, here's a function that flattens a sequence of sequences::
1779
1780 def flatten(seq):
1781 return [x for subseq in seq for x in subseq]
1782
1783 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
1784
1785This prints
1786
1787 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
1788
1789List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001790Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001791
1792
1793Extended Import Statement
1794-------------------------
1795
1796Many people have asked for a way to import a module under a different
1797name. This can be accomplished like this:
1798
1799 import foo
1800 bar = foo
1801 del foo
1802
1803but this common idiom gets old quickly. A simple extension of the
1804import statement now allows this to be written as follows:
1805
1806 import foo as bar
1807
1808There's also a variant for 'from ... import':
1809
1810 from foo import bar as spam
1811
1812This also works with packages; e.g. you can write this:
1813
1814 import test.regrtest as regrtest
1815
1816Note that 'as' is not a new keyword -- it is recognized only in this
1817context (this is only possible because the syntax for the import
1818statement doesn't involve expressions).
1819
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001820Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001821
1822
1823Extended Print Statement
1824------------------------
1825
1826Easily the most controversial new feature, this extension to the print
1827statement adds an option to make the output go to a different file
1828than the default sys.stdout.
1829
1830For example, to write an error message to sys.stderr, you can now
1831write:
1832
1833 print >> sys.stderr, "Error: bad dog!"
1834
1835As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00001836evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001837
1838 print >> None, "Hello world"
1839
1840is equivalent to
1841
1842 print "Hello world"
1843
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001844Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001845
1846
1847Optional Collection of Cyclical Garbage
1848---------------------------------------
1849
1850Python is now equipped with a garbage collector that can hunt down
1851cyclical references between Python objects. It's no replacement for
1852reference counting; in fact, it depends on the reference counts being
1853correct, and decides that a set of objects belong to a cycle if all
1854their reference counts can be accounted for from their references to
1855each other. This devious scheme was first proposed by Eric Tiedemann,
1856and brought to implementation by Neil Schemenauer.
1857
1858There's a module "gc" that lets you control some parameters of the
1859garbage collection. There's also an option to the configure script
1860that lets you enable or disable the garbage collection. In 2.0b1,
1861it's on by default, so that we (hopefully) can collect decent user
1862experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00001863performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001864off by default in the final 2.0 release.
1865
1866
1867Smaller Changes
1868---------------
1869
1870A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
1871map(None, seq1, seq2, ...) when the sequences have the same length;
1872i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
1873the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001874zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001875
1876sys.version_info is a tuple (major, minor, micro, level, serial).
1877
1878Dictionaries have an odd new method, setdefault(key, default).
1879dict.setdefault(key, default) returns dict[key] if it exists; if not,
1880it sets dict[key] to default and returns that value. Thus:
1881
1882 dict.setdefault(key, []).append(item)
1883
1884does the same work as this common idiom:
1885
1886 if not dict.has_key(key):
1887 dict[key] = []
1888 dict[key].append(item)
1889
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001890There are two new variants of SyntaxError that are raised for
1891indentation-related errors: IndentationError and TabError.
1892
1893Changed \x to consume exactly two hex digits; see PEP 223. Added \U
1894escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001895
1896The limits on the size of expressions and file in Python source code
1897have been raised from 2**16 to 2**32. Previous versions of Python
1898were limited because the maximum argument size the Python VM accepted
1899was 2**16. This limited the size of object constructor expressions,
1900e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
1901limit was raised thanks to a patch by Charles Waldman that effectively
1902fixes the problem. It is now much more likely that you will be
1903limited by available memory than by an arbitrary limit in Python.
1904
1905The interpreter's maximum recursion depth can be modified by Python
1906programs using sys.getrecursionlimit and sys.setrecursionlimit. This
1907limit is the maximum number of recursive calls that can be made by
1908Python code. The limit exists to prevent infinite recursion from
1909overflowing the C stack and causing a core dump. The default value is
19101000. The maximum safe value for a particular platform can be found
1911by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001912
1913New Modules and Packages
1914------------------------
1915
1916atexit - for registering functions to be called when Python exits.
1917
1918imputil - Greg Stein's alternative API for writing custom import
1919hooks.
1920
1921pyexpat - an interface to the Expat XML parser, contributed by Paul
1922Prescod.
1923
1924xml - a new package with XML support code organized (so far) in three
1925subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
1926would fill a volume. There's a special feature whereby a
1927user-installed package named _xmlplus overrides the standard
1928xmlpackage; this is intended to give the XML SIG a hook to distribute
1929backwards-compatible updates to the standard xml package.
1930
1931webbrowser - a platform-independent API to launch a web browser.
1932
1933
Guido van Rossume905e952000-09-05 12:42:46 +00001934Changed Modules
1935---------------
1936
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001937array -- new methods for array objects: count, extend, index, pop, and
1938remove
1939
1940binascii -- new functions b2a_hex and a2b_hex that convert between
1941binary data and its hex representation
1942
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001943calendar -- Many new functions that support features including control
1944over which day of the week is the first day, returning strings instead
1945of printing them. Also new symbolic constants for days of week,
1946e.g. MONDAY, ..., SUNDAY.
1947
1948cgi -- FieldStorage objects have a getvalue method that works like a
1949dictionary's get method and returns the value attribute of the object.
1950
1951ConfigParser -- The parser object has new methods has_option,
1952remove_section, remove_option, set, and write. They allow the module
1953to be used for writing config files as well as reading them.
1954
1955ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00001956optionally support the RFC 959 REST command.
1957
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001958gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00001959
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001960httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
1961the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00001962
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001963locale -- implement getdefaultlocale for Win32 and Macintosh
1964
1965marshal -- no longer dumps core when marshaling deeply nested or
1966recursive data structures
1967
1968os -- new functions isatty, seteuid, setegid, setreuid, setregid
1969
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001970os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
1971support under Unix.
1972
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001973os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001974
1975os.path -- fix semantics of os.path.commonprefix
1976
1977smtplib -- support for sending very long messages
1978
1979socket -- new function getfqdn()
1980
1981readline -- new functions to read, write and truncate history files.
1982The readline section of the library reference manual contains an
1983example.
1984
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001985select -- add interface to poll system call
1986
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001987shutil -- new copyfileobj function
1988
1989SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
1990HTTP server.
1991
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001992Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001993
1994urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00001995e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001996
1997whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00001998
1999
2000Obsolete Modules
2001----------------
2002
2003None. However note that 1.6 made a whole slew of modules obsolete:
2004stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2005poly, zmod, strop, util, whatsound.
2006
2007
2008Changed, New, Obsolete Tools
2009----------------------------
2010
Tim Peters8b092332000-09-05 20:15:25 +00002011None.
Guido van Rossume905e952000-09-05 12:42:46 +00002012
2013
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002014C-level Changes
2015---------------
2016
2017Several cleanup jobs were carried out throughout the source code.
2018
2019All C code was converted to ANSI C; we got rid of all uses of the
2020Py_PROTO() macro, which makes the header files a lot more readable.
2021
2022Most of the portability hacks were moved to a new header file,
2023pyport.h; several other new header files were added and some old
2024header files were removed, in an attempt to create a more rational set
2025of header files. (Few of these ever need to be included explicitly;
2026they are all included by Python.h.)
2027
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002028Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002029and Win64, especially for the new Intel Itanium processor. Mick also
2030added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002031
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002032The C APIs to return an object's size have been update to consistently
2033use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2034previous versions, the abstract interfaces used PyXXX_Length and the
2035concrete interfaces used PyXXX_Size. The old names,
2036e.g. PyObject_Length, are still available for backwards compatibility
2037at the API level, but are deprecated.
2038
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002039The PyOS_CheckStack function has been implemented on Windows by
2040Fredrik Lundh. It prevents Python from failing with a stack overflow
2041on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002042
2043The GC changes resulted in creation of two new slots on object,
2044tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002045the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002046
2047The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002048C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002049
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002050PyErr_Format has been updated to automatically calculate the size of
2051the buffer needed to hold the formatted result string. This change
2052prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002053
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002054New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002055
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002056PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2057that are the same as their non-Ex counterparts except they take an
2058extra flag argument that tells them to close the file when done.
2059
2060XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002061
Tim Peters8b092332000-09-05 20:15:25 +00002062
2063Windows Changes
2064---------------
2065
2066New popen2/popen3/peopen4 in os module (see Changed Modules above).
2067
2068os.popen is much more usable on Windows 95 and 98. See Microsoft
2069Knowledge Base article Q150956. The Win9x workaround described there
2070is implemented by the new w9xpopen.exe helper in the root of your
2071Python installation. Note that Python uses this internally; it is not
2072a standalone program.
2073
2074Administrator privileges are no longer required to install Python
2075on Windows NT or Windows 2000. If you have administrator privileges,
2076Python's registry info will be written under HKEY_LOCAL_MACHINE.
2077Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002078under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002079uses of Python, but will prevent some advanced uses from working
2080(for example, running a Python script as an NT service, or possibly
2081from CGI).
2082
2083[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2084installer; instead, it installs the needed Tcl/Tk files directly in the
2085Python directory. If you already have a Tcl/Tk installation, this
2086wastes some disk space (about 4 Megs) but avoids problems with
2087conflicting Tcl/Tk installations, and makes it much easier for Python
2088to ensure that Tcl/Tk can find all its files.
2089
2090[This was new in 1.6] The Windows installer now installs by default in
2091\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2092
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002093
2094Updates to the changes between 1.5.2 and 1.6
2095--------------------------------------------
2096
2097The 1.6 NEWS file can't be changed after the release is done, so here
2098is some late-breaking news:
2099
2100New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2101and changes to getlocale() and setlocale().
2102
2103The new module is now enabled per default.
2104
2105It is not true that the encodings codecs cannot be used for normal
2106strings: the string.encode() (which is also present on 8-bit strings
2107!) allows using them for 8-bit strings too, e.g. to convert files from
2108cp1252 (Windows) to latin-1 or vice-versa.
2109
2110Japanese codecs are available from Tamito KAJIYAMA:
2111http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2112
2113
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002114======================================================================