blob: 28f3492a06faea0fdcd8be13bf7453bace9006bd [file] [log] [blame]
Tim Peters20f51a72001-07-21 02:31:40 +00001What's New in Python 2.2a2?
2===========================
3
Martin v. Löwis339d0f72001-08-17 18:39:25 +00004Build
5
6- configure supports a new option --enable-unicode, with the values
7 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
8 type and supporting code is completely removed from the interpreter.
9
Tim Peters0afb6092001-08-15 06:06:44 +000010Tools
11
12- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +000013 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +000014 the module docstring for details.
15
Tim Peters20f51a72001-07-21 02:31:40 +000016Tests
17
Tim Peters5e824c32001-08-12 22:25:01 +000018- regrtest.py now knows which tests are expected to be skipped on some
19 platforms, allowing to give clearer test result output.
20
Tim Peters20f51a72001-07-21 02:31:40 +000021- Several new tests in the standard test suite, with special thanks to
22 Nick Mathewson.
23
24Core
25
Marc-André Lemburg888fac02001-07-31 14:24:31 +000026- Warnings about a mismatch in the Python API during extension import
27 now use the Python warning framework (which makes it possible to
28 write filters for these warnings).
29
Barry Warsaw9b3be7f2001-08-14 18:35:02 +000030- A function's __dict__ (aka func_dict) will now always be a
31 dictionary. It used to be possible to delete it or set it to None,
32 but now both actions raise TypeErrors. It is still legal to set it
33 to a dictionary object. Getting func.__dict__ before any attributes
34 have been assigned now returns an empty dictionary instead of None.
35
Marc-André Lemburgd6277912001-07-31 14:42:42 +000036Library
37
Tim Peters5e824c32001-08-12 22:25:01 +000038- New class Differ and new functions ndiff() and restore() in difflib.py.
39 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +000040 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +000041
Marc-André Lemburgd6277912001-07-31 14:42:42 +000042- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
43 value using the minimal quoting required for the value; more
44 reliable than using xml.sax.saxutils.escape() for attribute values.
45
46- Readline completion support for cmd.Cmd was added.
47
48New platforms
49
50C API
51
Marc-André Lemburg888fac02001-07-31 14:24:31 +000052- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
53 which provide a cross-platform implementations for the
54 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
55 the standard sprintf() and vsprintf() C lib APIs, these versions
56 apply bounds checking on the used buffer which enhances protection
57 against buffer overruns.
58
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +000059- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +000060 and extensions using different Unicode widths is rendered next to
61 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +000062 will result in an ImportError. Unicode extensions writers must make
63 sure to check the Unicode width compatibility in their extensions by
64 using at least one of the mangled Unicode APIs in the extension.
65
Martin v. Löwis339d0f72001-08-17 18:39:25 +000066- Two new flags METH_NOARGS and METH_O are available in method definition
67 tables to simplify implementation of methods with no arguments and a
68 single untyped argument. Calling such methods is more efficient than
69 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
70 deprecated.
71
Tim Petersc1731372001-08-04 08:12:36 +000072Windows
73
74- "import module" now compiles module.pyw if it exists and nothing else
75 relevant is found.
76
Tim Peters20f51a72001-07-21 02:31:40 +000077
Guido van Rossum55a78992001-07-17 17:22:32 +000078What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +000079===========================
80
81Core
Tim Petersa814db52001-05-14 07:05:58 +000082
Tim Peters6d6c1a32001-08-02 04:15:00 +000083- TENTATIVELY, a large amount of code implementing much of what's
84 described in PEP 252 (Making Types Look More Like Classes) and PEP
85 253 (Subtyping Built-in Types) was added. This will be released
86 with Python 2.2a1. Documentation will be provided separately
87 through http://www.python.org/2.2/. The purpose of releasing this
88 with Python 2.2a1 is to test backwards compatibility. It is
89 possible, though not likely, that a decision is made not to release
90 this code as part of 2.2 final, if any serious backwards
91 incompapatibilities are found during alpha testing that cannot be
92 repaired.
93
Guido van Rossum55a78992001-07-17 17:22:32 +000094- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +000095 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +000096 more 'yield' statements. See PEP 255. Since this adds a new
97 keyword to the language, this feature must be enabled by including a
98 future statement: "from __future__ import generators" (see PEP 236).
99 Generators will become a standard feature in a future release
100 (probably 2.3). Without this future statement, 'yield' remains an
101 ordinary identifier, but a warning is issued each time it is used.
102 (These warnings currently don't conform to the warnings framework of
103 PEP 230; we intend to fix this in 2.2a2.)
104
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000105- The UTF-16 codec was modified to be more RFC compliant. It will now
106 only remove BOM characters at the start of the string and then
107 only if running in native mode (UTF-16-LE and -BE won't remove a
108 leading BMO character).
109
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000110- Strings now have a new method .decode() to complement the already
111 existing .encode() method. These two methods provide direct access
112 to the corresponding decoders and encoders of the registered codecs.
113
114 To enhance the usability of the .encode() method, the special
115 casing of Unicode object return values was dropped (Unicode objects
116 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000117
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000118 Both methods will now return whatever the codec in charge of the
119 requested encoding returns as object, e.g. Unicode codecs will
120 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
121 will return u"äöü"). This enables codec writer to create codecs
122 for various simple to use conversions.
123
124 New codecs were added to demonstrate these new features (the .encode()
125 and .decode() columns indicate the type of the returned objects):
126
127 Name | .encode() | .decode() | Description
128 ----------------------------------------------------------------------
129 uu | string | string | UU codec (e.g. for email)
130 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000131 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000132 zlib | string | string | zlib compression
133 hex | string | string | 2-byte hex codec
134 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
135
Mark Hammond2a0af792001-05-14 03:09:36 +0000136- Some operating systems now support the concept of a default Unicode
137 encoding for file system operations. Notably, Windows supports 'mbcs'
138 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000139 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000140 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000141
142 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000143 functions that return filenames (such as os.listdir()) to return Python
144 string objects pre-encoded using the default file system encoding for
145 the platform. As this encoding is likely to be different from Python's
146 default encoding, converting this name to a Unicode object before passing
147 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000148 would attempt to use its default encoding (generally ASCII) rather than
149 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000150
Tim Petersa814db52001-05-14 07:05:58 +0000151 In general, this change simply removes surprises when working with
152 Unicode and the file system, making these operations work as you expect,
153 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000154 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000155
Tim Peters61dff2b2001-05-08 15:43:37 +0000156- Float (and complex) literals in source code were evaluated to full
157 precision only when running from a .py file; the same code loaded from a
158 .pyc (or .pyo) file could suffer numeric differences starting at about the
159 12th significant decimal digit. For example, on a machine with IEEE-754
160 floating arithmetic,
161
162 x = 9007199254740992.0
163 print long(x)
164
165 printed 9007199254740992 if run directly from .py, but 9007199254740000
166 if from a compiled (.pyc or .pyo) file. This was due to marshal using
167 str(float) instead of repr(float) when building code objects. marshal
168 now uses repr(float) instead, which should reproduce floats to full
169 machine precision (assuming the platform C float<->string I/O conversion
170 functions are of good quality).
171
172 This may cause floating-point results to change in some cases, and
173 usually for the better, but may also cause numerically unstable
174 algorithms to break.
175
Tim Peters2f228e72001-05-13 00:19:31 +0000176- The implementation of dicts suffers fewer collisions, which has speed
177 benefits. However, the order in which dict entries appear in dict.keys(),
178 dict.values() and dict.items() may differ from previous releases for a
179 given dict. Nothing is defined about this order, so no program should
180 rely on it. Nevertheless, it's easy to write test cases that rely on the
181 order by accident, typically because of printing the str() or repr() of a
182 dict to an "expected results" file. See Lib/test/test_support.py's new
183 sortdict(dict) function for a simple way to display a dict in sorted
184 order.
185
Tim Peters7a3bfc32001-06-12 01:22:22 +0000186- Many other small changes to dicts were made, resulting in faster
187 operation along the most common code paths.
188
Guido van Rossum10315822001-05-01 20:54:30 +0000189- Dictionary objects now support the "in" operator: "x in dict" means
190 the same as dict.has_key(x).
191
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000192- The update() method of dictionaries now accepts generic mapping
193 objects. Specifically the argument object must support the .keys()
194 and __getitem__() methods. This allows you to say, for example,
195 {}.update(UserDict())
196
Guido van Rossum10315822001-05-01 20:54:30 +0000197- Iterators were added; this is a generalized way of providing values
198 to a for loop. See PEP 234. There's a new built-in function iter()
199 to return an iterator. There's a new protocol to get the next value
200 from an iterator using the next() method (in Python) or the
201 tp_iternext slot (in C). There's a new protocol to get iterators
202 using the __iter__() method (in Python) or the tp_iter slot (in C).
203 Iterating (i.e. a for loop) over a dictionary generates its keys.
204 Iterating over a file generates its lines.
205
Tim Petersf553f892001-05-01 20:45:31 +0000206- The following functions were generalized to work nicely with iterator
207 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000208 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000209 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
210 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000211 join() method of strings
212 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000213 'x in y' and 'x not in y' (PySequence_Contains() in C API)
214 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000215 right-hand side of assignment statements with multiple targets, such as
216 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000217
Tim Petersd85e1022001-05-11 21:51:48 +0000218- Accessing module attributes is significantly faster (for example,
219 random.random or os.path or yourPythonModule.yourAttribute).
220
Tim Peterse63415e2001-05-08 04:38:29 +0000221- Comparing dictionary objects via == and != is faster, and now works even
222 if the keys and values don't support comparisons other than ==.
223
Tim Peters95bf9392001-05-10 08:32:44 +0000224- Comparing dictionaries in ways other than == and != is slower: there were
225 insecurities in the dict comparison implementation that could cause Python
226 to crash if the element comparison routines for the dict keys and/or
227 values mutated the dicts. Making the code bulletproof slowed it down.
228
Tim Peterseb28ef22001-06-02 05:27:19 +0000229- Collisions in dicts are resolved via a new approach, which can help
230 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000231 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000232 faster now. Thanks to Christian Tismer for pointing out the cause and
233 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000234
Tim Peters52e155e2001-06-16 05:42:57 +0000235- repr() is much faster for large containers (dict, list, tuple).
236
237
Tim Petersa814db52001-05-14 07:05:58 +0000238Library
239
Fred Drake960fdf92001-07-20 18:38:26 +0000240- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
241 were added to the string module. These a locale-indenpendent
242 constants, unlike letters, lowercase, and uppercase. These are now
243 use in appropriate locations in the standard library.
244
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000245- The flags used in dlopen calls can now be configured using
246 sys.setdlopenflags and queried using sys.getdlopenflags.
247
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000248- Fredrik Lundh's xmlrpclib is now a standard library module. This
249 provides full client-side XML-RPC support. In addition,
250 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
251 one asyncore-based). Thanks to Eric Raymond for the documentation.
252
Guido van Rossum643d3912001-07-05 14:46:25 +0000253- The xrange() object is simplified: it no longer supports slicing,
254 repetition, comparisons, efficient 'in' checking, the tolist()
255 method, or the start, stop and step attributes. See PEP 260.
256
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000257- A new function fnmatch.filter to filter lists of file names was added.
258
Barry Warsawffd674d2001-05-22 16:00:10 +0000259- calendar.py uses month and day names based on the current locale.
260
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000261- strop is now *really* obsolete (this was announced before with 1.6),
262 and issues DeprecationWarning when used (except for the four items
263 that are still imported into string.py).
264
Tim Petersa814db52001-05-14 07:05:58 +0000265- Cookie.py now sorts key+value pairs by key in output strings.
266
267- pprint.isrecursive(object) didn't correctly identify recursive objects.
268 Now it does.
269
Tim Peters95b3f782001-05-14 18:39:41 +0000270- pprint functions now much faster for large containers (tuple, list, dict).
271
Tim Peters7b9542a2001-06-10 23:40:19 +0000272- New 'q' and 'Q' format codes in the struct module, corresponding to C
273 types "long long" and "unsigned long long" (on Windows, __int64). In
274 native mode, these can be used only when the platform C compiler supports
275 these types (when HAVE_LONG_LONG is #define'd by the Python config
276 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000277 In standard mode, 'q' and 'Q' are supported on all platforms, and are
278 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000279
Guido van Rossum83213cc2001-06-12 16:48:52 +0000280- The site module installs a new built-in function 'help' that invokes
281 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
282 it displays a message reminding the user to use 'help()' or
283 'help(object)'.
284
Tim Petersa814db52001-05-14 07:05:58 +0000285Tests
286
287- New test_mutants.py runs dict comparisons where the key and value
288 comparison operators mutute the dicts randomly during comparison. This
289 rapidly causes Python to crash under earlier releases (not for the faint
290 of heart: it can also cause Win9x to freeze or reboot!).
291
292- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000293 pprint.isreadable() return sensible results. Also verifies that simple
294 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000295
Tim Peters58e0a8c2001-05-14 22:32:33 +0000296New platforms
297
298- Python should compile and run out of the box using the Borland C
299 compiler (under Windows), thanks to Stephen Hansen.
Tim Petersf553f892001-05-01 20:45:31 +0000300
Tim Peters4324aa32001-05-28 22:30:08 +0000301C API
302
303- Removed the unused last_is_sticky argument from the internal
304 _PyTuple_Resize(). If this affects you, you were cheating.
305
306
Guido van Rossum55a78992001-07-17 17:22:32 +0000307======================================================================
308
309
Guido van Rossumffe13be2001-04-16 18:46:45 +0000310What's New in Python 2.1 (final)?
311=================================
312
313We only changed a few things since the last release candidate, all in
314Python library code:
315
316- A bug in the locale module was fixed that affected locales which
317 define no grouping for numeric formatting.
318
319- A few bugs in the weakref module's implementations of weak
320 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
321 and the test suite was updated to check for these bugs.
322
323- An old bug in the os.path.walk() function (introduced in Python
324 2.0!) was fixed: a non-existent file would cause an exception
325 instead of being ignored.
326
327- Fixed a few bugs in the new symtable module found by Neil Norwitz's
328 PyChecker.
329
330
Guido van Rossum5b08f132001-04-16 02:05:23 +0000331What's New in Python 2.1c2?
332===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000333
Guido van Rossum5b08f132001-04-16 02:05:23 +0000334A flurry of small changes, and one showstopper fixed in the nick of
335time made it necessary to release another release candidate. The list
336here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000337
Guido van Rossum5b08f132001-04-16 02:05:23 +0000338Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000339
Guido van Rossum5b08f132001-04-16 02:05:23 +0000340- Tim discovered a nasty bug in the dictionary code, caused by
341 PyDict_Next() calling dict_resize(), and the GC code's use of
342 PyDict_Next() violating an assumption in dict_items(). This was
343 fixed with considerable amounts of band-aid, but the net effect is a
344 saner and more robust implementation.
345
346- Made a bunch of symbols static that were accidentally global.
347
348Build and Ports
349
350- The setup.py script didn't check for a new enough version of zlib
351 (1.1.3 is needed). Now it does.
352
353- Changed "make clean" target to also remove shared libraries.
354
355- Added a more general warning about the SGI Irix optimizer to README.
356
357Library
358
359- Fix a bug in urllib.basejoin("http://host", "../file.html") which
360 omitted the slash between host and file.html.
361
362- The mailbox module's _Mailbox class contained a completely broken
363 and undocumented seek() method. Ripped it out.
364
365- Fixed a bunch of typos in various library modules (urllib2, smtpd,
366 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
367
368- Fixed a few last-minute bugs in unittest.
369
370Extensions
371
372- Reverted the patch to the OpenSSL code in socketmodule.c to support
373 RAND_status() and the EGD, and the subsequent patch that tried to
374 fix it for pre-0.9.5 versions; the problem with the patch is that on
375 some systems it issues a warning whenever socket is imported, and
376 that's unacceptable.
377
378Tests
379
380- Fixed the pickle tests to work with "import test.test_pickle".
381
382- Tweaked test_locale.py to actually run the test Windows.
383
384- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
385 not "wb" (which is not a valid mode at all).
386
387- Fix pstats browser crashes. Import readline if it exists to make
388 the user interface nicer.
389
390- Add "import thread" to the top of test modules that import the
391 threading module (test_asynchat and test_threadedtempfile). This
392 prevents test failures caused by a broken threading module resulting
393 from a previously caught failed import.
394
395- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
396 needed on some platforms (e.g. Solaris 8) when the tests are run
397 twice in succession.
398
399- Skip rather than fail test_sunaudiodev if no audio device is found.
400
401
402What's New in Python 2.1c1?
403===========================
404
405This list was significantly updated when 2.1c2 was released; the 2.1c1
406release didn't mention most changes that were actually part of 2.1c1:
407
408Legal
409
410- Copyright was assigned to the Python Software Foundation (PSF) and a
411 PSF license (very similar to the CNRI license) was added.
412
413- The CNRI copyright notice was updated to include 2001.
414
415Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000416
Guido van Rossumc9932722001-04-12 02:31:27 +0000417- After a public outcry, assignment to __debug__ is no longer illegal;
418 instead, a warning is issued. It will become illegal in 2.2.
419
Guido van Rossum5b08f132001-04-16 02:05:23 +0000420- Fixed a core dump with "%#x" % 0, and changed the semantics so that
421 "%#x" now always prepends "0x", even if the value is zero.
422
423- Fixed some nits in the bytecode compiler.
424
425- Fixed core dumps when calling certain kinds of non-functions.
426
427- Fixed various core dumps caused by reference count bugs.
428
429Build and Ports
430
431- Use INSTALL_SCRIPT to install script files.
432
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000433- New port: SCO Unixware 7, by Billy G. Allie.
434
Guido van Rossum5b08f132001-04-16 02:05:23 +0000435- Updated RISCOS port.
436
437- Updated BeOS port and notes.
438
439- Various other porting problems resolved.
440
441Library
442
443- The TERMIOS and SOCKET modules are now truly obsolete and
444 unnecessary. Their symbols are incorporated in the termios and
445 socket modules.
446
447- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
448 better tests for pickling.
449
450- threading: make Condition.wait() robust against KeyboardInterrupt.
451
452- zipfile: add support to zipfile to support opening an archive
453 represented by an open file rather than a file name. Fix bug where
454 the archive was not properly closed. Fixed a bug in this bugfix
455 where flush() was called for a read-only file.
456
457- imputil: added an uninstall() method to the ImportManager.
458
459- Canvas: fixed bugs in lower() and tkraise() methods.
460
461- SocketServer: API change (added overridable close_request() method)
462 so that the TCP server can explicitly close the request.
463
464- pstats: Eric Raymond added a simple interactive statistics browser,
465 invoked when the module is run as a script.
466
467- locale: fixed a problem in format().
468
469- webbrowser: made it work when the BROWSER environment variable has a
470 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
471 KDE 2. Fixed some other nits.
472
473- unittest: changes to allow using a different exception than
474 AssertionError, and added a few more function aliases. Some other
475 small changes.
476
477- urllib, urllib2: fixed redirect problems and a coupleof other nits.
478
479- asynchat: fixed a critical bug in asynchat that slipped through the
480 2.1b2 release. Fixed another rare bug.
481
482- Fix some unqualified except: clauses (always a bad code example).
483
484XML
485
486- pyexpat: new API get_version_string().
487
488- Fixed some minidom bugs.
489
490Extensions
491
492- Fixed a core dump in _weakref. Removed the weakref.mapping()
493 function (it adds nothing to the API).
494
495- Rationalized the use of header files in the readline module, to make
496 it compile (albeit with some warnings) with the very recent readline
497 4.2, without breaking for earlier versions.
498
499- Hopefully fixed a buffering problem in linuxaudiodev.
500
501- Attempted a fix to make the OpenSSL support in the socket module
502 work again with pre-0.9.5 versions of OpenSSL.
503
504Tests
505
506- Added a test case for asynchat and asyncore.
507
508- Removed coupling between tests where one test failing could break
509 another.
510
511Tools
512
513- Ping added an interactive help browser to pydoc, fixed some nits
514 in the rest of the pydoc code, and added some features to his
515 inspect module.
516
517- An updated python-mode.el version 4.1 which integrates Ken
518 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
519 much nicer in XEmacs and Emacs. When stepping through your program
520 with pdb, in either the shell window or the *Python* window, the
521 source file and line will be tracked by an arrow. Very cool!
522
523- IDLE: syntax warnings in interactive mode are changed into errors.
524
525- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +0000526 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +0000527
528- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000529
Barry Warsaw11e89c72001-04-11 20:37:57 +0000530
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000531What's New in Python 2.1 beta 2?
532================================
533
Guido van Rossum053ae352001-03-22 14:17:21 +0000534(Unlisted are many fixed bugs, more documentation, etc.)
535
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000536Core language, builtins, and interpreter
537
Guido van Rossum053ae352001-03-22 14:17:21 +0000538- The nested scopes work (enabled by "from __future__ import
539 nested_scopes") is completed; in particular, the future now extends
540 into code executed through exec, eval() and execfile(), and into the
541 interactive interpreter.
542
543- When calling a base class method (e.g. BaseClass.__init__(self)),
544 this is now allowed even if self is not strictly spoken a class
545 instance (e.g. when using metaclasses or the Don Beaudry hook).
546
547- Slice objects are now comparable but not hashable; this prevents
548 dict[:] from being accepted but meaningless.
549
550- Complex division is now calculated using less braindead algorithms.
551 This doesn't change semantics except it's more likely to give useful
552 results in extreme cases. Complex repr() now uses full precision
553 like float repr().
554
555- sgmllib.py now calls handle_decl() for simple <!...> declarations.
556
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000557- It is illegal to assign to the name __debug__, which is set when the
558 interpreter starts. It is effectively a compile-time constant.
559
560- A warning will be issued if a global statement for a variable
561 follows a use or assignment of that variable.
562
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000563Standard library
564
Guido van Rossum053ae352001-03-22 14:17:21 +0000565- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
566 inspired by JUnit), is now part of the standard library. You now
567 have a choice of two testing frameworks: unittest requires you to
568 write testcases as separate code, doctest gathers them from
569 docstrings. Both approaches have their advantages and
570 disadvantages.
571
572- A new module Tix was added, which wraps the Tix extension library
573 for Tk. With that module, it is not necessary to statically link
574 Tix with _tkinter, since Tix will be loaded with Tcl's "package
575 require" command. See Demo/tix/.
576
577- tzparse.py is now obsolete.
578
579- In gzip.py, the seek() and tell() methods are removed -- they were
580 non-functional anyway, and it's better if callers can test for their
581 existence with hasattr().
582
583Python/C API
584
585- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
586 that's already in the dictionary during a PyDict_Next() iteration.
587 This used to fail occasionally when a dictionary resize operation
588 could be triggered that would rehash all the keys. All other
589 modifications to the dictionary are still off-limits during a
590 PyDict_Next() iteration!
591
592- New extended APIs related to passing compiler variables around.
593
594- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
595 implement isinstance() and issubclass().
596
597- Py_BuildValue() now has a "D" conversion to create a Python complex
598 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000599
Fred Drake4e262a92001-03-22 18:26:47 +0000600- Extensions types which support weak references must now set the
601 field allocated for the weak reference machinery to NULL themselves;
602 this is done to avoid the cost of checking each object for having a
603 weakly referencable type in PyObject_INIT(), since most types are
604 not weakly referencable.
605
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000606- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
607 free variables and cell variables to and from the frame's f_locals.
608
609- Variants of several functions defined in pythonrun.h have been added
610 to support the nested_scopes future statement. The variants all end
611 in Flags and take an extra argument, a PyCompilerFlags *; examples:
612 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
613 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +0000614 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000615
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000616Distutils
617
618- the sdist command now writes a PKG-INFO file, as described in PEP 241,
619 into the release tree.
620
Tim Peters0e57abf2001-05-02 07:39:38 +0000621- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000622 (an uninstaller, more customization of the installer's display)
623
624- from Jack Jansen: added Mac-specific code to generate a dialog for
625 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +0000626 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000627 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +0000628
629- added 'platforms' and 'keywords' to the set of metadata that can be
630 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000631
632- applied patches from Jason Tishler to make the compiler class work with
633 Cygwin.
634
635
Tim Peters2fe289a2001-03-01 22:19:38 +0000636What's New in Python 2.1 beta 1?
637================================
Tim Petersd66595f2001-02-04 03:09:53 +0000638
639Core language, builtins, and interpreter
640
Guido van Rossum9d0fbde2001-03-02 14:00:32 +0000641- Following an outcry from the community about the amount of code
642 broken by the nested scopes feature introduced in 2.1a2, we decided
643 to make this feature optional, and to wait until Python 2.2 (or at
644 least 6 months) to make it standard. The option can be enabled on a
645 per-module basis by adding "from __future__ import nested_scopes" at
646 the beginning of a module (before any other statements, but after
647 comments and an optional docstring). See PEP 236 (Back to the
648 __future__) for a description of the __future__ statement. PEP 227
649 (Statically Nested Scopes) has been updated to reflect this change,
650 and to clarify the semantics in a number of endcases.
651
652- The nested scopes code, when enabled, has been hardened, and most
653 bugs and memory leaks in it have been fixed.
654
655- Compile-time warnings are now generated for a number of conditions
656 that will break or change in meaning when nested scopes are enabled:
657
658 - Using "from...import *" or "exec" without in-clause in a function
659 scope that also defines a lambda or nested function with one or
660 more free (non-local) variables. The presence of the import* or
661 bare exec makes it impossible for the compiler to determine the
662 exact set of local variables in the outer scope, which makes it
663 impossible to determine the bindings for free variables in the
664 inner scope. To avoid the warning about import *, change it into
665 an import of explicitly name object, or move the import* statement
666 to the global scope; to avoid the warning about bare exec, use
667 exec...in... (a good idea anyway -- there's a possibility that
668 bare exec will be deprecated in the future).
669
670 - Use of a global variable in a nested scope with the same name as a
671 local variable in a surrounding scope. This will change in
672 meaning with nested scopes: the name in the inner scope will
673 reference the variable in the outer scope rather than the global
674 of the same name. To avoid the warning, either rename the outer
675 variable, or use a global statement in the inner function.
676
Neil Schemenauera35c6882001-02-27 04:45:05 +0000677- An optional object allocator has been included. This allocator is
678 optimized for Python objects and should be faster and use less memory
679 than the standard system allocator. It is not enabled by default
680 because of possible thread safety problems. The allocator is only
681 protected by the Python interpreter lock and it is possible that some
682 extension modules require a thread safe allocator. The object
683 allocator can be enabled by providing the "--with-pymalloc" option to
684 configure.
685
Tim Petersd66595f2001-02-04 03:09:53 +0000686Standard library
687
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000688- pyexpat now detects the expat version if expat.h defines it. A
689 number of additional handlers are provided, which are only available
690 since expat 1.95. In addition, the methods SetParamEntityParsing and
691 GetInputContext of Parser objects are available with 1.95.x
692 only. Parser objects now provide the ordered_attributes and
693 specified_attributes attributes. A new module expat.model was added,
694 which offers a number of additional constants if 1.95.x is used.
695
696- xml.dom offers the new functions registerDOMImplementation and
697 getDOMImplementation.
698
699- xml.dom.minidom offers a toprettyxml method. A number of DOM
700 conformance issues have been resolved. In particular, Element now
701 has an hasAttributes method, and the handling of namespaces was
702 improved.
703
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000704- Ka-Ping Yee contributed two new modules: inspect.py, a module for
705 getting information about live Python code, and pydoc.py, a module
706 for interactively converting docstrings to HTML or text.
707 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +0000708 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +0000709 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
710 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000711
Tim Peters1eff7962001-03-01 02:31:33 +0000712- New library module difflib.py, primarily packaging the SequenceMatcher
713 class at the heart of the popular ndiff.py file-comparison tool.
714
715- doctest.py (a framework for verifying Python code examples in docstrings)
716 is now part of the std library.
717
Tim Petersd66595f2001-02-04 03:09:53 +0000718Windows changes
719
Guido van Rossume3955a82001-03-02 14:05:59 +0000720- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
721 small GUI that lets you browse the module docstrings using your
722 default web browser.
723
Tim Peters1eff7962001-03-01 02:31:33 +0000724- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
725 Platforms) is implemented. See
726
727 http://python.sourceforge.net/peps/pep-0235.html
728
729 for full details, especially the "Current Lower-Left Semantics" section.
730 The new Windows import rules are simpler than before:
731
732 A. If the PYTHONCASEOK environment variable exists, same as
733 before: silently accept the first case-insensitive match of any
734 kind; raise ImportError if none found.
735
736 B. Else search sys.path for the first case-sensitive match; raise
737 ImportError if none found.
738
739 The same rules have been implented on other platforms with case-
740 insensitive but case-preserving filesystems too (including Cygwin, and
741 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +0000742
Tim Peters25a9ce32001-02-19 07:06:36 +0000743- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
744 what it's supposed to do (and does do under NT and 2000) via direct
745 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +0000746 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +0000747 all Win9x systems before.
748
Tim Peters1eff7962001-03-01 02:31:33 +0000749- Build: Subproject _test (effectively) renamed to _testcapi.
750
Tim Peters2fe289a2001-03-01 22:19:38 +0000751New platforms
752
753- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
754 Thanks to Steven Majewski!
755
756- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
757 Tishler!
758
Guido van Rossum9089b272001-03-02 06:49:50 +0000759- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
760 Schwertberger! See RISCOS/README for more information -- it seems
761 that because of the bizarre filename conventions on RISCOS, no port
762 to that platform is easy. Note that the new variable os.endsep is
763 silently supported in order to make life easier on this platform,
764 but we don't advertise it because it's not worth for most folks to
765 care about RISCOS portability.
766
Tim Peters25a9ce32001-02-19 07:06:36 +0000767
Tim Petersd7b5e882001-01-25 03:36:26 +0000768What's New in Python 2.1 alpha 2?
769=================================
Tim Peters40ead762001-01-27 05:35:26 +0000770
Tim Petersd7b5e882001-01-25 03:36:26 +0000771Core language, builtins, and interpreter
772
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000773- Scopes nest. If a name is used in a function or class, but is not
774 local, the definition in the nearest enclosing function scope will
775 be used. One consequence of this change is that lambda statements
776 could reference variables in the namespaces where the lambda is
777 defined. In some unusual cases, this change will break code.
778
779 In all previous version of Python, names were resolved in exactly
780 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000781 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000782 function A is defined within a function B, the names bound in B are
783 not visible in A. The new rules make names bound in B visible in A,
784 unless A contains a name binding that hides the binding in B.
785
786 Section 4.1 of the reference manual describes the new scoping rules
787 in detail. The test script in Lib/test/test_scope.py demonstrates
788 some of the effects of the change.
789
790 The new rules will cause existing code to break if it defines nested
791 functions where an outer function has local variables with the same
792 name as globals or builtins used by the inner function. Example:
793
794 def munge(str):
795 def helper(x):
796 return str(x)
797 if type(str) != type(''):
798 str = helper(str)
799 return str.strip()
800
801 Under the old rules, the name str in helper() is bound to the
802 builtin function str(). Under the new rules, it will be bound to
803 the argument named str and an error will occur when helper() is
804 called.
805
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000806- The compiler will report a SyntaxError if "from ... import *" occurs
807 in a function or class scope. The language reference has documented
808 that this case is illegal, but the compiler never checked for it.
809 The recent introduction of nested scope makes the meaning of this
810 form of name binding ambiguous. In a future release, the compiler
811 may allow this form when there is no possibility of ambiguity.
812
Tim Peters40ead762001-01-27 05:35:26 +0000813- repr(string) is easier to read, now using hex escapes instead of octal,
814 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
815
816 >>> "\texample \r\n" + chr(0) + chr(255)
817 '\texample \r\n\x00\xff' # in 2.1
818 '\011example \015\012\000\377' # in 2.0
819
Moshe Zadka6af0ce02001-01-29 06:41:00 +0000820- Functions are now compared and hashed by identity, not by value, since
821 the func_code attribute is writable.
822
Fred Drakefb9d7122001-02-01 20:00:40 +0000823- Weak references (PEP 205) have been added. This involves a few
824 changes in the core, an extension module (_weakref), and a Python
825 module (weakref). The weakref module is the public interface. It
826 includes support for "explicit" weak references, proxy objects, and
827 mappings with weakly held values.
828
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000829- A 'continue' statement can now appear in a try block within the body
830 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +0000831 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000832
Tim Petersd7b5e882001-01-25 03:36:26 +0000833Standard library
834
Barry Warsaw30dbd142001-01-31 22:14:01 +0000835- mailbox.py now has a new class, PortableUnixMailbox which is
836 identical to UnixMailbox but uses a more portable scheme for
837 determining From_ separators. Also, the constructors for all the
838 classes in this module have a new optional `factory' argument, which
839 is a callable used when new message classes must be instantiated by
840 the next() method.
841
Tim Petersd7b5e882001-01-25 03:36:26 +0000842- random.py is now self-contained, and offers all the functionality of
843 the now-deprecated whrandom.py. See the docs for details. random.py
844 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +0000845 and restoring the internal state of the generator; and jumpahead(n),
846 for quickly forcing the internal state to be the same as if n calls to
847 random() had been made. The latter is particularly useful for multi-
848 threaded programs, creating one instance of the random.Random() class for
849 each thread, then using .jumpahead() to force each instance to use a
850 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +0000851
Tim Peters0de88fc2001-02-01 04:59:18 +0000852- random.py's seed() function is new. For bit-for-bit compatibility with
853 prior releases, use the whseed function instead. The new seed function
854 addresses two problems: (1) The old function couldn't produce more than
855 about 2**24 distinct internal states; the new one about 2**45 (the best
856 that can be done in the Wichmann-Hill generator). (2) The old function
857 sometimes produced identical internal states when passed distinct
858 integers, and there was no simple way to predict when that would happen;
859 the new one guarantees to produce distinct internal states for all
860 arguments in [0, 27814431486576L).
861
Jeremy Hylton4c4fda02001-02-02 03:29:24 +0000862- The socket module now supports raw packets on Linux. The socket
863 family is AF_PACKET.
864
Tim Peters9ea17ac2001-02-02 05:57:15 +0000865- test_capi.py is a start at running tests of the Python C API. The tests
866 are implemented by the new Modules/_testmodule.c.
867
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000868- A new extension module, _symtable, provides provisional access to the
869 internal symbol table used by the Python compiler. A higher-level
870 interface will be added on top of _symtable in a future release.
871
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +0000872- Removed the obsolete soundex module.
873
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000874- xml.dom.minidom now uses the standard DOM exceptions. Node supports
875 the isSameNode method; NamedNodeMap the get method.
876
877- xml.sax.expatreader supports the lexical handler property; it
878 generates comment, startCDATA, and endCDATA events.
879
Tim Petersee826f82001-01-31 19:39:44 +0000880Windows changes
881
882- Build procedure: the zlib project is built in a different way that
883 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +0000884 the zlib binary used. See PCbuild\readme.txt for details. Your old
885 zlib-related directories can be deleted; you'll need to download fresh
886 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +0000887
Tim Peters9ea17ac2001-02-02 05:57:15 +0000888- Build: New subproject _test for the benefit of test_capi.py (see above).
889
Tim Petersb16c56f2001-02-02 21:24:51 +0000890- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
891 interface to some Python compiler internals).
892
893- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +0000894 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +0000895
Tim Petersa3a3a032000-11-30 05:22:44 +0000896What's New in Python 2.1 alpha 1?
897=================================
898
899Core language, builtins, and interpreter
900
Marc-André Lemburgebb195b2001-01-20 10:34:52 +0000901- There is a new Unicode companion to the PyObject_Str() API
902 called PyObject_Unicode(). It behaves in the same way as the
903 former, but assures that the returned value is an Unicode object
904 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +0000905
Guido van Rossumf98eda02001-01-17 15:54:45 +0000906- The comparison operators support "rich comparison overloading" (PEP
907 207). C extension types can provide a rich comparison function in
908 the new tp_richcompare slot in the type object. The cmp() function
909 and the C function PyObject_Compare() first try the new rich
910 comparison operators before trying the old 3-way comparison. There
911 is also a new C API PyObject_RichCompare() (which also falls back on
912 the old 3-way comparison, but does not constrain the outcome of the
913 rich comparison to a Boolean result).
914
915 The rich comparison function takes two objects (at least one of
916 which is guaranteed to have the type that provided the function) and
917 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
918 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
919 object, which may be NotImplemented (in which case the tp_compare
920 slot function is used as a fallback, if defined).
921
922 Classes can overload individual comparison operators by defining one
923 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +0000924 __ge__. There are no explicit "reflected argument" versions of
925 these; instead, __lt__ and __gt__ are each other's reflection,
926 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
927 reflection (similar at the C level). No other implications are
928 made; in particular, Python does not assume that == is the Boolean
929 inverse of !=, or that < is the Boolean inverse of >=. This makes
930 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +0000931
932 Classes or types that want to implement (in)equality tests but not
933 the ordering operators (i.e. unordered types) should implement ==
934 and !=, and raise an error for the ordering operators.
935
Guido van Rossuma88479f2001-01-18 14:28:08 +0000936 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +0000937 Boolean; e.g. a matrix type might want to return a matrix of bits
938 for A < B, giving elementwise comparisons. Such types should ensure
939 that any interpretation of their value in a Boolean context raises
940 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
941 at the C level) to always raise an exception.
942
Guido van Rossuma88479f2001-01-18 14:28:08 +0000943- Complex numbers use rich comparisons to define == and != but raise
944 an exception for <, <=, > and >=. Unfortunately, this also means
945 that cmp() of two complex numbers raises an exception when the two
946 numbers differ. Since it is not mathematically meaningful to compare
947 complex numbers except for equality, I hope that this doesn't break
948 too much code.
949
Tim Peters3389f192001-02-18 08:48:49 +0000950- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +0000951 not defined by the language, other than that it's arbitrary but
952 consistent (see the Reference Manual). An implementation detail changed
953 in 2.1a1 such that None now compares less than any other object. Code
954 relying on this new behavior (like code that relied on the previous
955 behavior) does so at its own risk.
956
Barry Warsaw573b5412001-01-15 20:43:18 +0000957- Functions and methods now support getting and setting arbitrarily
958 named attributes (PEP 232). Functions have a new __dict__
959 (a.k.a. func_dict) which hold the function attributes. Methods get
960 and set attributes on their underlying im_func. It is a TypeError
961 to set an attribute on a bound method.
962
Guido van Rossum051e3352001-01-15 19:11:10 +0000963- The xrange() object implementation has been improved so that
964 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
965 limitation that in this case len(xrange(sys.maxint)) can't be
966 calculated, but the common idiom "for i in xrange(sys.maxint)" will
967 work fine as long as the index i doesn't actually reach 2**31.
968 (Python uses regular ints for sequence and string indices; fixing
969 that is much more work.)
970
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000971- Two changes to from...import:
972
Guido van Rossumba381232001-02-03 15:06:40 +0000973 1) "from M import X" now works even if (after loading module M)
974 sys.modules['M'] is not a real module; it's basically a getattr()
975 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000976
977 2) "from M import *" now looks for M.__all__ to decide which names to
978 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
979 filters out names starting with '_' as before. Whether or not
980 __all__ exists, there's no restriction on the type of M.
981
Guido van Rossumf61f1662001-01-10 20:13:55 +0000982- File objects have a new method, xreadlines(). This is the fastest
983 way to iterate over all lines in a file:
984
985 for line in file.xreadlines():
986 ...do something to line...
987
988 See the xreadlines module (mentioned below) for how to do this for
989 other file-like objects.
990
991- Even if you don't use file.xreadlines(), you may expect a speedup on
992 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +0000993 quite a bit in platform-specific ways: on systems (like Linux) that
994 support flockfile(), getc_unlocked(), and funlockfile(), those are
995 used by default. On systems (like Windows) without getc_unlocked(),
996 a complicated (but still thread-safe) method using fgets() is used by
997 default.
998
Tim Petersd52269b2001-01-25 06:23:18 +0000999 You can force use of the fgets() method by #define'ing
1000 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001001 getc_unlocked()).
1002
Tim Petersd52269b2001-01-25 06:23:18 +00001003 You can force fgets() not to be used by #define'ing
1004 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001005 test_bufio.py fails -- and let us know if it does!).
1006
1007- In addition, the fileinput module, while still slower than the other
1008 methods on most platforms, has been sped up too, by using
1009 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001010
1011- Support for run-time warnings has been added, including a new
1012 command line option (-W) to specify the disposition of warnings.
1013 See the description of the warnings module below.
1014
1015- Extensive changes have been made to the coercion code. This mostly
1016 affects extension modules (which can now implement mixed-type
1017 numerical operators without having to use coercion), but
1018 occasionally, in boundary cases the coercion semantics have changed
1019 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001020 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001021 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001022 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001023
Guido van Rossumf98eda02001-01-17 15:54:45 +00001024- In connection with the coercion changes, a new built-in singleton
1025 object, NotImplemented is defined. This can be returned for
1026 operations that wish to indicate they are not implemented for a
1027 particular combination of arguments. From C, this is
1028 Py_NotImplemented.
1029
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001030- The interpreter accepts now bytecode files on the command line even
1031 if they do not have a .pyc or .pyo extension. On Linux, after executing
1032
Martin v. Löwise214baa2001-02-04 22:37:56 +00001033import imp,sys,string
1034magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1035reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1036open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001037
1038 any byte code file can be used as an executable (i.e. as an argument
1039 to execve(2)).
1040
Tim Peters9940b802000-12-01 07:59:35 +00001041- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001042 character. In 1.6 and earlier, they never produced a sign,
1043 and raised an error if the value of the long was too large
1044 to fit in a Python int. In 2.0, they produced a sign if and
1045 only if too large to fit in an int. This was inconsistent
1046 across platforms (because the size of an int varies across
1047 platforms), and inconsistent with hex() and oct(). Example:
1048
1049 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001050 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001051 'ffffffbe' # in 2.0 and before, on 32-bit machines
1052 >>> hex(-0x42L)
1053 '-0x42L' # in all versions of Python
1054
Tim Peters9940b802000-12-01 07:59:35 +00001055 The behavior of %d formats for negative Python longs remains
1056 the same as in 2.0 (although in 1.6 and before, they raised
1057 an error if the long didn't fit in a Python int).
1058
1059 %u formats don't make sense for Python longs, but are allowed
1060 and treated the same as %d in 2.1. In 2.0, a negative long
1061 formatted via %u produced a sign if and only if too large to
1062 fit in an int. In 1.6 and earlier, a negative long formatted
1063 via %u raised an error if it was too big to fit in an int.
1064
Guido van Rossum3661d392000-12-12 22:10:31 +00001065- Dictionary objects have an odd new method, popitem(). This removes
1066 an arbitrary item from the dictionary and returns it (in the form of
1067 a (key, value) pair). This can be useful for algorithms that use a
1068 dictionary as a bag of "to do" items and repeatedly need to pick one
1069 item. Such algorithms normally end up running in quadratic time;
1070 using popitem() they can usually be made to run in linear time.
1071
Tim Peters36cdad12000-12-29 02:06:45 +00001072Standard library
1073
Thomas Woutersfe385252001-01-19 23:16:56 +00001074- In the time module, the time argument to the functions strftime,
1075 localtime, gmtime, asctime and ctime is now optional, defaulting to
1076 the current time (in the local timezone).
1077
Guido van Rossumda91f222001-01-15 16:36:08 +00001078- The ftplib module now defaults to passive mode, which is deemed a
1079 more useful default given that clients are often inside firewalls
1080 these days. Note that this could break if ftplib is used to connect
1081 to a *server* that is inside a firewall, from outside; this is
1082 expected to be a very rare situation. To fix that, you can call
1083 ftp.set_pasv(0).
1084
Martin v. Löwis10a27872001-01-13 09:54:41 +00001085- The module site now treats .pth files not only for path configuration,
1086 but also supports extensions to the initialization code: Lines starting
1087 with import are executed.
1088
Guido van Rossumf61f1662001-01-10 20:13:55 +00001089- There's a new module, warnings, which implements a mechanism for
1090 issuing and filtering warnings. There are some new built-in
1091 exceptions that serve as warning categories, and a new command line
1092 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1093 turns warnings into errors). warnings.warn(message[, category])
1094 issues a warning message; this can also be called from C as
1095 PyErr_Warn(category, message).
1096
1097- A new module xreadlines was added. This exports a single factory
1098 function, xreadlines(). The intention is that this code is the
1099 absolutely fastest way to iterate over all lines in an open
1100 file(-like) object:
1101
1102 import xreadlines
1103 for line in xreadlines.xreadlines(file):
1104 ...do something to line...
1105
1106 This is equivalent to the previous the speed record holder using
1107 file.readlines(sizehint). Note that if file is a real file object
1108 (as opposed to a file-like object), this is equivalent:
1109
1110 for line in file.xreadlines():
1111 ...do something to line...
1112
Tim Peters36cdad12000-12-29 02:06:45 +00001113- The bisect module has new functions bisect_left, insort_left,
1114 bisect_right and insort_right. The old names bisect and insort
1115 are now aliases for bisect_right and insort_right. XXX_right
1116 and XXX_left methods differ in what happens when the new element
1117 compares equal to one or more elements already in the list: the
1118 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001119 right. Code that doesn't care where equal elements end up should
1120 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001121
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001122- The new curses.panel module wraps the panel library that forms part
1123 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1124
Guido van Rossumf61f1662001-01-10 20:13:55 +00001125- The SocketServer module now sets the allow_reuse_address flag by
1126 default in the TCPServer class.
1127
1128- A new function, sys._getframe(), returns the stack frame pointer of
1129 the caller. This is intended only as a building block for
1130 higher-level mechanisms such as string interpolation.
1131
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001132- The pyexpat module supports a number of new handlers, which are
1133 available only in expat 1.2. If invocation of a callback fails, it
1134 will report an additional frame in the traceback. Parser objects
1135 participate now in garbage collection. If expat reports an unknown
1136 encoding, pyexpat will try to use a Python codec; that works only
1137 for single-byte charsets. The parser type objects is exposed as
1138 XMLParserObject.
1139
1140- xml.dom now offers standard definitions for symbolic node type and
1141 exception code constants, and a hierarchy of DOM exceptions. minidom
1142 was adjusted to use them.
1143
1144- The conformance of xml.dom.minidom to the DOM specification was
1145 improved. It detects a number of additional error cases; the
1146 previous/next relationship works even when the tree is modified;
1147 Node supports the normalize() method; NamedNodeMap, DocumentType and
1148 DOMImplementation classes were added; Element supports the
1149 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1150 method.
1151
Guido van Rossumf61f1662001-01-10 20:13:55 +00001152Build issues
1153
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001154- For Unix (and Unix-compatible) builds, configuration and building of
1155 extension modules is now greatly automated. Rather than having to
1156 edit the Modules/Setup file to indicate which modules should be
1157 built and where their include files and libraries are, a
1158 distutils-based setup.py script now takes care of building most
1159 extension modules. All extension modules built this way are built
1160 as shared libraries. Only a few modules that must be linked
1161 statically are still listed in the Setup file; you won't need to
1162 edit their configuration.
1163
1164- Python should now build out of the box on Cygwin. If it doesn't,
1165 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001166
1167- Python now always uses its own (renamed) implementation of getopt()
1168 -- there's too much variation among C library getopt()
1169 implementations.
1170
1171- C++ compilers are better supported; the CXX macro is always set to a
1172 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001173
Tim Petersd92dfe02000-12-12 01:18:41 +00001174Windows changes
1175
1176- select module: By default under Windows, a select() call
1177 can specify no more than 64 sockets. Python now boosts
1178 this Microsoft default to 512. If you need even more than
1179 that, see the MS docs (you'll need to #define FD_SETSIZE
1180 and recompile Python from source).
1181
Guido van Rossumf61f1662001-01-10 20:13:55 +00001182- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1183 subdirectory is no more!
1184
Tim Petersa3a3a032000-11-30 05:22:44 +00001185
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001186What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001187=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001188
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001189Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001190changes are in the file HISTORY. If you are making the jump directly
1191from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1192HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001193
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001194Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1195the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1196http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001197
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001198--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001199
1200======================================================================
1201
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001202What's new in 2.0 (since release candidate 1)?
1203==============================================
1204
1205Standard library
1206
1207- The copy_reg module was modified to clarify its intended use: to
1208 register pickle support for extension types, not for classes.
1209 pickle() will raise a TypeError if it is passed a class.
1210
1211- Fixed a bug in gettext's "normalize and expand" code that prevented
1212 it from finding an existing .mo file.
1213
1214- Restored support for HTTP/0.9 servers in httplib.
1215
Tim Peters989b7b92000-10-16 20:24:53 +00001216- The math module was changed to stop raising OverflowError in case of
1217 underflow, and return 0 instead in underflow cases. Whether Python
1218 used to raise OverflowError in case of underflow was platform-
1219 dependent (it did when the platform math library set errno to ERANGE
1220 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001221
1222- Fixed a bug in StringIO that occurred when the file position was not
1223 at the end of the file and write() was called with enough data to
1224 extend past the end of the file.
1225
1226- Fixed a bug that caused Tkinter error messages to get lost on
1227 Windows. The bug was fixed by replacing direct use of
1228 interp->result with Tcl_GetStringResult(interp).
1229
1230- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1231 redirect response.
1232
1233- Several changes were made to distutils: Some debugging code was
1234 removed from util. Fixed the installer used when an external zip
1235 program (like WinZip) is not found; the source code for this
1236 installer is in Misc/distutils. check_lib() was modified to behave
1237 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1238 test for whether installed modules are on sys.path was changed to
1239 use both normcase() and normpath().
1240
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001241- Several minor bugs were fixed in the xml package (the minidom,
1242 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001243
1244- The regression test driver (regrtest.py) behavior when invoked with
1245 -l changed: It now reports a count of objects that are recognized as
1246 garbage but not freed by the garbage collector.
1247
Tim Peters989b7b92000-10-16 20:24:53 +00001248- The regression test for the math module was changed to test
1249 exceptional behavior when the test is run in verbose mode. Python
1250 cannot yet guarantee consistent exception behavior across platforms,
1251 so the exception part of test_math is run only in verbose mode, and
1252 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001253
1254Internals
1255
1256- PyOS_CheckStack() has been disabled on Win64, where it caused
1257 test_sre to fail.
1258
1259Build issues
1260
1261- Changed compiler flags, so that gcc is always invoked with -Wall and
1262 -Wstrict-prototypes. Users compiling Python with GCC should see
1263 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001264 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001265 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001266
Tim Petersa3a3a032000-11-30 05:22:44 +00001267- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001268
1269Tools and other miscellany
1270
1271- The compiler in Tools/compiler was updated to support the new
1272 language features introduced in 2.0: extended print statement, list
1273 comprehensions, and augmented assignments. The new compiler should
1274 also be backwards compatible with Python 1.5.2; the compiler will
1275 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001276 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001277
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001278What's new in 2.0 release candidate 1 (since beta 2)?
1279=====================================================
1280
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001281What is release candidate 1?
1282
1283We believe that release candidate 1 will fix all known bugs that we
1284intend to fix for the 2.0 final release. This release should be a bit
1285more stable than the previous betas. We would like to see even more
1286widespread testing before the final release, so we are producing this
1287release candidate. The final release will be exactly the same unless
1288any show-stopping (or brown bag) bugs are found by testers of the
1289release candidate.
1290
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001291All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001292to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001293
1294Core language, builtins, and interpreter
1295
1296- A bug that caused crashes when __coerce__ was used with augmented
1297 assignment, e.g. +=, was fixed.
1298
1299- Raise ZeroDivisionError when raising zero to a negative number,
1300 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1301 power operator and the result of math.pow(0.0, -2.0) will vary by
1302 platform. On Linux, it raises a ValueError.
1303
1304- A bug in Unicode string interpolation was fixed that occasionally
1305 caused errors with formats including "%%". For example, the
1306 following expression "%% %s" % u"abc" no longer raises a TypeError.
1307
1308- Compilation of deeply nested expressions raises MemoryError instead
1309 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1310
1311- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1312 rendering them useless. They are now written in binary mode again.
1313
1314Standard library
1315
1316- Keyword arguments are now accepted for most pattern and match object
1317 methods in SRE, the standard regular expression engine.
1318
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001319- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001320 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001321
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001322- Several bugs in the Unicode handling and error handling in _tkinter
1323 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001324
1325- Fix memory management errors in Merge() and Tkapp_Call() routines.
1326
1327- Several changes were made to cStringIO to make it compatible with
1328 the file-like object interface and with StringIO. If operations are
1329 performed on a closed object, an exception is raised. The truncate
1330 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001331 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001332
1333- There were many changes made to the linuxaudiodev module and its
1334 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001335 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001336
1337 Note that this module is named poorly, because it should work
1338 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001339 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001340
1341 The module now raises exceptions when errors occur instead of
1342 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1343 audio) and defines a getptr() method that calls the
1344 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1345
1346- The library_version attribute, introduced in an earlier beta, was
1347 removed because it can not be supported with early versions of the C
1348 readline library, which provides no way to determine the version at
1349 compile-time.
1350
1351- The binascii module is now enabled on Win64.
1352
Tim Peters46446d62000-10-09 21:19:31 +00001353- tokenize.py no longer suffers "recursion depth" errors when parsing
1354 programs with very long string literals.
1355
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001356Internals
1357
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001358- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001359 which is called when the interpreter starts up to determine where
1360 the standard library is installed. These vulnerabilities affect all
1361 previous versions of Python and can be exploited by setting very
1362 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1363 setuid Python script, although use of the wrapper in
1364 Misc/setuid-prog.c will eliminate the vulnerability.
1365
1366- Fixed garbage collection bugs in instance creation that were
1367 triggered when errors occurred during initialization. The solution,
1368 applied in cPickle and in PyInstance_New(), is to call
1369 PyObject_GC_Init() after the initialization of the object's
1370 container attributes is complete.
1371
1372- pyexpat adds definitions of PyModule_AddStringConstant and
1373 PyModule_AddObject if the Python version is less than 2.0, which
1374 provides compatibility with PyXML on Python 1.5.2.
1375
1376- If the platform has a bogus definition for LONG_BIT (the number of
1377 bits in a long), an error will be reported at compile time.
1378
1379- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1380 collection crashes and possibly other, unreported crashes.
1381
1382- Fixed a memory leak in _PyUnicode_Fini().
1383
1384Build issues
1385
1386- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001387 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001388 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001389
1390- The mmap.PAGESIZE constant is now initialized using sysconf when
1391 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1392
1393- The md5 file should now compile on all platforms.
1394
1395- The select module now compiles on platforms that do not define
1396 POLLRDNORM and related constants.
1397
1398- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001399 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001400
Jeremy Hylton10921202000-10-09 18:34:12 +00001401- BeOS: A number of changes were made to the build and installation
1402 process. ar-fake now operates on a directory of object files.
1403 dl_export.h is gone, and its macros now appear on the mwcc command
1404 line during build on PPC BeOS.
1405
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001406- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001407 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001408
1409- Cygwin: Support for shared libraries, Tkinter, and sockets.
1410
1411- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1412
1413Tools and other miscellany
1414
1415- Removed debugging prints from main used with freeze.
1416
Tim Peters46446d62000-10-09 21:19:31 +00001417- IDLE auto-indent no longer crashes when it encounters Unicode
1418 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001419
1420What's new in 2.0 beta 2 (since beta 1)?
1421========================================
1422
1423Core language, builtins, and interpreter
1424
Tim Peters482c0212000-09-26 06:33:09 +00001425- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001426 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001427
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001428- Add -h and -V command line options to print the usage message and
1429 Python version number and exit immediately.
1430
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001431- eval() and exec accept Unicode objects as code parameters.
1432
1433- getattr() and setattr() now also accept Unicode objects for the
1434 attribute name, which are converted to strings using the default
1435 encoding before lookup.
1436
1437- Multiplication on string and Unicode now does proper bounds
1438 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1439 string is too long."
1440
1441- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001442 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001443
Jeremy Hylton1b618592000-09-26 05:32:36 +00001444
1445Standard library and extensions
1446
Guido van Rossum5b08f132001-04-16 02:05:23 +00001447- socket module: the OpenSSL code now adds support for RAND_status()
1448 and EGD (Entropy Gathering Device).
1449
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001450- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001451 argument checking; it still takes no arguments.
1452
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001453- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001454
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001455- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001456
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001457- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001458
1459- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001460 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001461
1462- copy: Copy Unicode objects atomically.
1463
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001464- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001465
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001466- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001467
Fred Drake67233bc2000-09-26 16:40:27 +00001468- dbm: Add get() and setdefault() methods to dbm object. Add constant
1469 `library' to module that names the library used. Added doc strings
1470 and method names to error messages. Uses configure to determine
1471 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
1472 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001473
1474- distutils: Update to version 0.9.3.
1475
1476- dl: Add several dl.RTLD_ constants.
1477
1478- fpectl: Now supported on FreeBSD.
1479
1480- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
1481 found by the collector will be saved in gc.garbage. This is useful
1482 for debugging a program that creates reference cycles.
1483
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001484- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00001485 of HTTP class. Do not close socket on zero-length response. Do not
1486 crash when server sends invalid content-length header.
1487
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001488- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001489
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001490- marshal: When reading a short, sign-extend on platforms where shorts
1491 are bigger than 16 bits. When reading a long, repair the unportable
1492 sign extension that was being done for 64-bit machines. (It assumed
1493 that signed right shift sign-extends.)
1494
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001495- operator: Add contains(), invert(), __invert__() as aliases for
1496 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001497
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001498- os: Add support for popen2() and popen3() on all platforms where
1499 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001500
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001501- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00001502 clicking on a file in Explorer (or passing the file name to the
1503 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001504
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001505- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00001506 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001507
1508- pickle: Now raises ValueError when an invalid pickle that contains
1509 a non-string repr where a string repr was expected. This behavior
1510 matches cPickle.
1511
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001512- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001513
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001514- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001515
1516- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001517 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001518 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001519
1520- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001521 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001522
1523- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00001524 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00001525 few cycles during startup since the first call to
1526 setdefaultencoding() will initialize the codec registry and the
1527 encodings package.
1528
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001529- socket: Support for size hint in readlines() method of object returned
1530 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001531
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001532- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001533 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001534 is followed by whitespace.
1535
Tim Petersa3a3a032000-11-30 05:22:44 +00001536- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001537
1538- struct: Check ranges for bytes and shorts.
1539
1540- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001541 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001542
1543- Tkinter: Image objects are now guaranteed to have unique ids. Set
1544 event.delta to zero if Tk version doesn't support mousewheel.
1545 Removed some debugging prints.
1546
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001547- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001548
Fred Drake67233bc2000-09-26 16:40:27 +00001549- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001550 which works around a bug in Norton AntiVirus 2000 that leads directly
1551 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001552
1553- xml: New version detection code allows PyXML to override standard
1554 XML package if PyXML version is greater than 0.6.1.
1555
Fred Drake64bb3802000-09-26 16:21:35 +00001556- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
1557 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
1558 tree only for nodes which are sufficiently interesting to a specific
1559 application. Does not provide the HTML-specific extensions. Still
1560 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001561
Fred Drake64bb3802000-09-26 16:21:35 +00001562- xml.sax: SAX 2 support for Python, including all the handler
1563 interfaces needed to process XML 1.0 compliant XML. Some
1564 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001565
Fred Drake64bb3802000-09-26 16:21:35 +00001566- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
1567 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001568
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001569
Jeremy Hylton1b618592000-09-26 05:32:36 +00001570C API
1571
1572- Add three new convenience functions for module initialization --
1573 PyModule_AddObject(), PyModule_AddIntConstant(), and
1574 PyModule_AddStringConstant().
1575
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001576- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00001577 removed and add #error to Python.h if NULL isn't defined after
1578 #include of stdio.h.
1579
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001580- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00001581 backwards compatibility (at the source level) with old extensions.
1582
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001583- A wrapper API was added for signal() and sigaction(). Instead of
1584 either function, always use PyOS_getsig() to get a signal handler
1585 and PyOS_setsig() to set one. A new convenience typedef
1586 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001587
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001588- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00001589 internal data buffer and size of a string object -- or the default
1590 encoded version of a Unicode object.
1591
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001592- PyString_Size() and PyString_AsString() accept Unicode objects.
1593
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001594- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00001595 exists). INT_MAX and LONG_MAX will always be defined, even if
1596 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001597
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001598- PyFloat_FromString takes a second argument, pend, that was
1599 effectively useless. It is now officially useless but preserved for
1600 backwards compatibility. If the pend argument is not NULL, *pend is
1601 set to NULL.
1602
1603- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
1604 for the attribute name. See note on getattr() above.
1605
1606- A few bug fixes to argument processing for Unicode.
1607 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
1608 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
1609 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00001610 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001611
1612- Py_BuildValue accepts B format (for bgen-generated code).
1613
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001614
Jeremy Hylton1b618592000-09-26 05:32:36 +00001615Internals
1616
1617- On Unix, fix code for finding Python installation directory so that
1618 it works when argv[0] is a relative path.
1619
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00001620- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001621 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00001622 rather than by generating a copy of the object.
1623
Tim Peters482c0212000-09-26 06:33:09 +00001624- Several of the internal Unicode tables are much smaller now, and
1625 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001626
Jeremy Hylton97693b02000-09-26 17:42:51 +00001627- In the garbage collector: Fixed bug in collection of tuples. Fixed
1628 bug that caused some instances to be removed from the container set
1629 while they were still live. Fixed parsing in gc.set_debug() for
1630 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001631
1632- Fixed refcount problem in instance deallocation that only occurred
1633 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
1634
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001635- On Windows, getpythonregpath is now protected against null data in
1636 registry key.
1637
1638- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00001639 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001640
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001641
Jeremy Hylton1b618592000-09-26 05:32:36 +00001642Build and platform-specific issues
1643
1644- Better support of GNU Pth via --with-pth configure option.
1645
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001646- Python/C API now properly exposed to dynamically-loaded extension
1647 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001648
1649- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
1650 Don't define MS_SYNC to be zero when it is undefined. Added missing
1651 prototypes in posixmodule.c.
1652
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001653- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001654 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001655
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001656- Fix largefile support on older NetBSD systems and OpenBSD by adding
1657 define for TELL64.
1658
1659
1660Tools and other miscellany
1661
1662- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
1663
1664- freeze: The modulefinder now works with 2.0 opcodes.
1665
Tim Petersa3a3a032000-11-30 05:22:44 +00001666- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001667 Move hackery of sys.argv until after the Tk instance has been
1668 created, which allows the application-specific Tkinter
1669 initialization to be executed if present; also pass an explicit
1670 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00001671
Jeremy Hylton1b618592000-09-26 05:32:36 +00001672
1673What's new in 2.0 beta 1?
1674=========================
1675
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001676Source Incompatibilities
1677------------------------
1678
1679None. Note that 1.6 introduced several incompatibilities with 1.5.2,
1680such as single-argument append(), connect() and bind(), and changes to
1681str(long) and repr(float).
1682
1683
1684Binary Incompatibilities
1685------------------------
1686
1687- Third party extensions built for Python 1.5.x or 1.6 cannot be used
1688with Python 2.0; these extensions will have to be rebuilt for Python
16892.0.
1690
1691- On Windows, attempting to import a third party extension built for
1692Python 1.5.x or 1.6 results in an immediate crash; there's not much we
1693can do about this. Check your PYTHONPATH environment variable!
1694
1695- Python bytecode files (*.pyc and *.pyo) are not compatible between
1696releases.
1697
1698
1699Overview of Changes Since 1.6
1700-----------------------------
1701
1702There are many new modules (including brand new XML support through
1703the xml package, and i18n support through the gettext module); a list
1704of all new modules is included below. Lots of bugs have been fixed.
1705
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001706The process for making major new changes to the language has changed
1707since Python 1.6. Enhancements must now be documented by a Python
1708Enhancement Proposal (PEP) before they can be accepted.
1709
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001710There are several important syntax enhancements, described in more
1711detail below:
1712
1713 - Augmented assignment, e.g. x += 1
1714
1715 - List comprehensions, e.g. [x**2 for x in range(10)]
1716
1717 - Extended import statement, e.g. import Module as Name
1718
1719 - Extended print statement, e.g. print >> file, "Hello"
1720
1721Other important changes:
1722
1723 - Optional collection of cyclical garbage
1724
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001725Python Enhancement Proposal (PEP)
1726---------------------------------
1727
1728PEP stands for Python Enhancement Proposal. A PEP is a design
1729document providing information to the Python community, or describing
1730a new feature for Python. The PEP should provide a concise technical
1731specification of the feature and a rationale for the feature.
1732
1733We intend PEPs to be the primary mechanisms for proposing new
1734features, for collecting community input on an issue, and for
1735documenting the design decisions that have gone into Python. The PEP
1736author is responsible for building consensus within the community and
1737documenting dissenting opinions.
1738
1739The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001740
1741Augmented Assignment
1742--------------------
1743
1744This must have been the most-requested feature of the past years!
1745Eleven new assignment operators were added:
1746
Guido van Rossume905e952000-09-05 12:42:46 +00001747 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001748
1749For example,
1750
1751 A += B
1752
1753is similar to
1754
1755 A = A + B
1756
1757except that A is evaluated only once (relevant when A is something
1758like dict[index].attr).
1759
1760However, if A is a mutable object, A may be modified in place. Thus,
1761if A is a number or a string, A += B has the same effect as A = A+B
1762(except A is only evaluated once); but if a is a list, A += B has the
1763same effect as A.extend(B)!
1764
1765Classes and built-in object types can override the new operators in
1766order to implement the in-place behavior; the not-in-place behavior is
1767used automatically as a fallback when an object doesn't implement the
1768in-place behavior. For classes, the method name is derived from the
1769method name for the corresponding not-in-place operator by inserting
1770an 'i' in front of the name, e.g. __iadd__ implements in-place
1771__add__.
1772
1773Augmented assignment was implemented by Thomas Wouters.
1774
1775
1776List Comprehensions
1777-------------------
1778
1779This is a flexible new notation for lists whose elements are computed
1780from another list (or lists). The simplest form is:
1781
1782 [<expression> for <variable> in <sequence>]
1783
Guido van Rossum56db0952000-09-06 23:34:25 +00001784For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001785This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001786
1787You can also add a condition:
1788
1789 [<expression> for <variable> in <sequence> if <condition>]
1790
1791For example, [w for w in words if w == w.lower()] would yield the list
1792of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001793than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001794
1795You can also have nested for loops and more than one 'if' clause. For
1796example, here's a function that flattens a sequence of sequences::
1797
1798 def flatten(seq):
1799 return [x for subseq in seq for x in subseq]
1800
1801 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
1802
1803This prints
1804
1805 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
1806
1807List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001808Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001809
1810
1811Extended Import Statement
1812-------------------------
1813
1814Many people have asked for a way to import a module under a different
1815name. This can be accomplished like this:
1816
1817 import foo
1818 bar = foo
1819 del foo
1820
1821but this common idiom gets old quickly. A simple extension of the
1822import statement now allows this to be written as follows:
1823
1824 import foo as bar
1825
1826There's also a variant for 'from ... import':
1827
1828 from foo import bar as spam
1829
1830This also works with packages; e.g. you can write this:
1831
1832 import test.regrtest as regrtest
1833
1834Note that 'as' is not a new keyword -- it is recognized only in this
1835context (this is only possible because the syntax for the import
1836statement doesn't involve expressions).
1837
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001838Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001839
1840
1841Extended Print Statement
1842------------------------
1843
1844Easily the most controversial new feature, this extension to the print
1845statement adds an option to make the output go to a different file
1846than the default sys.stdout.
1847
1848For example, to write an error message to sys.stderr, you can now
1849write:
1850
1851 print >> sys.stderr, "Error: bad dog!"
1852
1853As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00001854evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001855
1856 print >> None, "Hello world"
1857
1858is equivalent to
1859
1860 print "Hello world"
1861
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001862Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001863
1864
1865Optional Collection of Cyclical Garbage
1866---------------------------------------
1867
1868Python is now equipped with a garbage collector that can hunt down
1869cyclical references between Python objects. It's no replacement for
1870reference counting; in fact, it depends on the reference counts being
1871correct, and decides that a set of objects belong to a cycle if all
1872their reference counts can be accounted for from their references to
1873each other. This devious scheme was first proposed by Eric Tiedemann,
1874and brought to implementation by Neil Schemenauer.
1875
1876There's a module "gc" that lets you control some parameters of the
1877garbage collection. There's also an option to the configure script
1878that lets you enable or disable the garbage collection. In 2.0b1,
1879it's on by default, so that we (hopefully) can collect decent user
1880experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00001881performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001882off by default in the final 2.0 release.
1883
1884
1885Smaller Changes
1886---------------
1887
1888A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
1889map(None, seq1, seq2, ...) when the sequences have the same length;
1890i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
1891the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001892zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001893
1894sys.version_info is a tuple (major, minor, micro, level, serial).
1895
1896Dictionaries have an odd new method, setdefault(key, default).
1897dict.setdefault(key, default) returns dict[key] if it exists; if not,
1898it sets dict[key] to default and returns that value. Thus:
1899
1900 dict.setdefault(key, []).append(item)
1901
1902does the same work as this common idiom:
1903
1904 if not dict.has_key(key):
1905 dict[key] = []
1906 dict[key].append(item)
1907
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001908There are two new variants of SyntaxError that are raised for
1909indentation-related errors: IndentationError and TabError.
1910
1911Changed \x to consume exactly two hex digits; see PEP 223. Added \U
1912escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001913
1914The limits on the size of expressions and file in Python source code
1915have been raised from 2**16 to 2**32. Previous versions of Python
1916were limited because the maximum argument size the Python VM accepted
1917was 2**16. This limited the size of object constructor expressions,
1918e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
1919limit was raised thanks to a patch by Charles Waldman that effectively
1920fixes the problem. It is now much more likely that you will be
1921limited by available memory than by an arbitrary limit in Python.
1922
1923The interpreter's maximum recursion depth can be modified by Python
1924programs using sys.getrecursionlimit and sys.setrecursionlimit. This
1925limit is the maximum number of recursive calls that can be made by
1926Python code. The limit exists to prevent infinite recursion from
1927overflowing the C stack and causing a core dump. The default value is
19281000. The maximum safe value for a particular platform can be found
1929by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001930
1931New Modules and Packages
1932------------------------
1933
1934atexit - for registering functions to be called when Python exits.
1935
1936imputil - Greg Stein's alternative API for writing custom import
1937hooks.
1938
1939pyexpat - an interface to the Expat XML parser, contributed by Paul
1940Prescod.
1941
1942xml - a new package with XML support code organized (so far) in three
1943subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
1944would fill a volume. There's a special feature whereby a
1945user-installed package named _xmlplus overrides the standard
1946xmlpackage; this is intended to give the XML SIG a hook to distribute
1947backwards-compatible updates to the standard xml package.
1948
1949webbrowser - a platform-independent API to launch a web browser.
1950
1951
Guido van Rossume905e952000-09-05 12:42:46 +00001952Changed Modules
1953---------------
1954
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001955array -- new methods for array objects: count, extend, index, pop, and
1956remove
1957
1958binascii -- new functions b2a_hex and a2b_hex that convert between
1959binary data and its hex representation
1960
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001961calendar -- Many new functions that support features including control
1962over which day of the week is the first day, returning strings instead
1963of printing them. Also new symbolic constants for days of week,
1964e.g. MONDAY, ..., SUNDAY.
1965
1966cgi -- FieldStorage objects have a getvalue method that works like a
1967dictionary's get method and returns the value attribute of the object.
1968
1969ConfigParser -- The parser object has new methods has_option,
1970remove_section, remove_option, set, and write. They allow the module
1971to be used for writing config files as well as reading them.
1972
1973ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00001974optionally support the RFC 959 REST command.
1975
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001976gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00001977
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001978httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
1979the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00001980
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001981locale -- implement getdefaultlocale for Win32 and Macintosh
1982
1983marshal -- no longer dumps core when marshaling deeply nested or
1984recursive data structures
1985
1986os -- new functions isatty, seteuid, setegid, setreuid, setregid
1987
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001988os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
1989support under Unix.
1990
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001991os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001992
1993os.path -- fix semantics of os.path.commonprefix
1994
1995smtplib -- support for sending very long messages
1996
1997socket -- new function getfqdn()
1998
1999readline -- new functions to read, write and truncate history files.
2000The readline section of the library reference manual contains an
2001example.
2002
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002003select -- add interface to poll system call
2004
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002005shutil -- new copyfileobj function
2006
2007SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2008HTTP server.
2009
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002010Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002011
2012urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002013e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002014
2015whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002016
2017
2018Obsolete Modules
2019----------------
2020
2021None. However note that 1.6 made a whole slew of modules obsolete:
2022stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2023poly, zmod, strop, util, whatsound.
2024
2025
2026Changed, New, Obsolete Tools
2027----------------------------
2028
Tim Peters8b092332000-09-05 20:15:25 +00002029None.
Guido van Rossume905e952000-09-05 12:42:46 +00002030
2031
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002032C-level Changes
2033---------------
2034
2035Several cleanup jobs were carried out throughout the source code.
2036
2037All C code was converted to ANSI C; we got rid of all uses of the
2038Py_PROTO() macro, which makes the header files a lot more readable.
2039
2040Most of the portability hacks were moved to a new header file,
2041pyport.h; several other new header files were added and some old
2042header files were removed, in an attempt to create a more rational set
2043of header files. (Few of these ever need to be included explicitly;
2044they are all included by Python.h.)
2045
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002046Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002047and Win64, especially for the new Intel Itanium processor. Mick also
2048added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002049
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002050The C APIs to return an object's size have been update to consistently
2051use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2052previous versions, the abstract interfaces used PyXXX_Length and the
2053concrete interfaces used PyXXX_Size. The old names,
2054e.g. PyObject_Length, are still available for backwards compatibility
2055at the API level, but are deprecated.
2056
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002057The PyOS_CheckStack function has been implemented on Windows by
2058Fredrik Lundh. It prevents Python from failing with a stack overflow
2059on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002060
2061The GC changes resulted in creation of two new slots on object,
2062tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002063the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002064
2065The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002066C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002067
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002068PyErr_Format has been updated to automatically calculate the size of
2069the buffer needed to hold the formatted result string. This change
2070prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002071
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002072New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002073
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002074PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2075that are the same as their non-Ex counterparts except they take an
2076extra flag argument that tells them to close the file when done.
2077
2078XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002079
Tim Peters8b092332000-09-05 20:15:25 +00002080
2081Windows Changes
2082---------------
2083
2084New popen2/popen3/peopen4 in os module (see Changed Modules above).
2085
2086os.popen is much more usable on Windows 95 and 98. See Microsoft
2087Knowledge Base article Q150956. The Win9x workaround described there
2088is implemented by the new w9xpopen.exe helper in the root of your
2089Python installation. Note that Python uses this internally; it is not
2090a standalone program.
2091
2092Administrator privileges are no longer required to install Python
2093on Windows NT or Windows 2000. If you have administrator privileges,
2094Python's registry info will be written under HKEY_LOCAL_MACHINE.
2095Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002096under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002097uses of Python, but will prevent some advanced uses from working
2098(for example, running a Python script as an NT service, or possibly
2099from CGI).
2100
2101[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2102installer; instead, it installs the needed Tcl/Tk files directly in the
2103Python directory. If you already have a Tcl/Tk installation, this
2104wastes some disk space (about 4 Megs) but avoids problems with
2105conflicting Tcl/Tk installations, and makes it much easier for Python
2106to ensure that Tcl/Tk can find all its files.
2107
2108[This was new in 1.6] The Windows installer now installs by default in
2109\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2110
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002111
2112Updates to the changes between 1.5.2 and 1.6
2113--------------------------------------------
2114
2115The 1.6 NEWS file can't be changed after the release is done, so here
2116is some late-breaking news:
2117
2118New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2119and changes to getlocale() and setlocale().
2120
2121The new module is now enabled per default.
2122
2123It is not true that the encodings codecs cannot be used for normal
2124strings: the string.encode() (which is also present on 8-bit strings
2125!) allows using them for 8-bit strings too, e.g. to convert files from
2126cp1252 (Windows) to latin-1 or vice-versa.
2127
2128Japanese codecs are available from Tamito KAJIYAMA:
2129http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2130
2131
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002132======================================================================