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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.
Jack Jansen32ce0cd2001-08-21 19:28:20 +00009
10- A new configure option --enable-framework builds a Mac OS X framework,
11 which "make frameworkinstall" will install. This provides a starting
12 point for more mac-like functionality, join pythonmac-sig@python.org
13 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +000014
Tim Peters0afb6092001-08-15 06:06:44 +000015Tools
16
17- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +000018 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +000019 the module docstring for details.
20
Tim Peters20f51a72001-07-21 02:31:40 +000021Tests
22
Tim Peters5e824c32001-08-12 22:25:01 +000023- regrtest.py now knows which tests are expected to be skipped on some
24 platforms, allowing to give clearer test result output.
25
Tim Peters20f51a72001-07-21 02:31:40 +000026- Several new tests in the standard test suite, with special thanks to
27 Nick Mathewson.
28
29Core
30
Tim Peters6cd6a822001-08-17 22:11:27 +000031- Future statements are now effective in simulated interactive shells
32 (like IDLE). This should "just work" by magic, but read Michael
33 Hudson's "Future statements in simulated shells" PEP 264 for full
34 details: <http://python.sf.net/peps/pep-0264.html>.
35
Guido van Rossumf86ddd22001-08-17 21:21:04 +000036- The type/class unification (PEP 252-253) was integrated into the
37 trunk and is not so tentative any more (the exact specification of
38 some features is still tentative). A lot of work has done on fixing
39 bugs and adding robustness and features (performance still has to
40 come a long way).
41
Marc-André Lemburg888fac02001-07-31 14:24:31 +000042- Warnings about a mismatch in the Python API during extension import
43 now use the Python warning framework (which makes it possible to
44 write filters for these warnings).
45
Barry Warsaw9b3be7f2001-08-14 18:35:02 +000046- A function's __dict__ (aka func_dict) will now always be a
47 dictionary. It used to be possible to delete it or set it to None,
48 but now both actions raise TypeErrors. It is still legal to set it
49 to a dictionary object. Getting func.__dict__ before any attributes
50 have been assigned now returns an empty dictionary instead of None.
51
Marc-André Lemburgd6277912001-07-31 14:42:42 +000052Library
53
Tim Peters5e824c32001-08-12 22:25:01 +000054- New class Differ and new functions ndiff() and restore() in difflib.py.
55 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +000056 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +000057
Marc-André Lemburgd6277912001-07-31 14:42:42 +000058- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
59 value using the minimal quoting required for the value; more
60 reliable than using xml.sax.saxutils.escape() for attribute values.
61
62- Readline completion support for cmd.Cmd was added.
63
64New platforms
65
66C API
67
Marc-André Lemburg888fac02001-07-31 14:24:31 +000068- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
69 which provide a cross-platform implementations for the
70 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
71 the standard sprintf() and vsprintf() C lib APIs, these versions
72 apply bounds checking on the used buffer which enhances protection
73 against buffer overruns.
74
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +000075- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +000076 and extensions using different Unicode widths is rendered next to
77 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +000078 will result in an ImportError. Unicode extensions writers must make
79 sure to check the Unicode width compatibility in their extensions by
80 using at least one of the mangled Unicode APIs in the extension.
81
Martin v. Löwis339d0f72001-08-17 18:39:25 +000082- Two new flags METH_NOARGS and METH_O are available in method definition
83 tables to simplify implementation of methods with no arguments and a
84 single untyped argument. Calling such methods is more efficient than
85 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
86 deprecated.
87
Tim Petersc1731372001-08-04 08:12:36 +000088Windows
89
90- "import module" now compiles module.pyw if it exists and nothing else
91 relevant is found.
92
Tim Peters20f51a72001-07-21 02:31:40 +000093
Guido van Rossum55a78992001-07-17 17:22:32 +000094What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +000095===========================
96
97Core
Tim Petersa814db52001-05-14 07:05:58 +000098
Tim Peters6d6c1a32001-08-02 04:15:00 +000099- TENTATIVELY, a large amount of code implementing much of what's
100 described in PEP 252 (Making Types Look More Like Classes) and PEP
101 253 (Subtyping Built-in Types) was added. This will be released
102 with Python 2.2a1. Documentation will be provided separately
103 through http://www.python.org/2.2/. The purpose of releasing this
104 with Python 2.2a1 is to test backwards compatibility. It is
105 possible, though not likely, that a decision is made not to release
106 this code as part of 2.2 final, if any serious backwards
107 incompapatibilities are found during alpha testing that cannot be
108 repaired.
109
Guido van Rossum55a78992001-07-17 17:22:32 +0000110- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000111 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000112 more 'yield' statements. See PEP 255. Since this adds a new
113 keyword to the language, this feature must be enabled by including a
114 future statement: "from __future__ import generators" (see PEP 236).
115 Generators will become a standard feature in a future release
116 (probably 2.3). Without this future statement, 'yield' remains an
117 ordinary identifier, but a warning is issued each time it is used.
118 (These warnings currently don't conform to the warnings framework of
119 PEP 230; we intend to fix this in 2.2a2.)
120
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000121- The UTF-16 codec was modified to be more RFC compliant. It will now
122 only remove BOM characters at the start of the string and then
123 only if running in native mode (UTF-16-LE and -BE won't remove a
124 leading BMO character).
125
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000126- Strings now have a new method .decode() to complement the already
127 existing .encode() method. These two methods provide direct access
128 to the corresponding decoders and encoders of the registered codecs.
129
130 To enhance the usability of the .encode() method, the special
131 casing of Unicode object return values was dropped (Unicode objects
132 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000133
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000134 Both methods will now return whatever the codec in charge of the
135 requested encoding returns as object, e.g. Unicode codecs will
136 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
137 will return u"äöü"). This enables codec writer to create codecs
138 for various simple to use conversions.
139
140 New codecs were added to demonstrate these new features (the .encode()
141 and .decode() columns indicate the type of the returned objects):
142
143 Name | .encode() | .decode() | Description
144 ----------------------------------------------------------------------
145 uu | string | string | UU codec (e.g. for email)
146 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000147 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000148 zlib | string | string | zlib compression
149 hex | string | string | 2-byte hex codec
150 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
151
Mark Hammond2a0af792001-05-14 03:09:36 +0000152- Some operating systems now support the concept of a default Unicode
153 encoding for file system operations. Notably, Windows supports 'mbcs'
154 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000155 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000156 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000157
158 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000159 functions that return filenames (such as os.listdir()) to return Python
160 string objects pre-encoded using the default file system encoding for
161 the platform. As this encoding is likely to be different from Python's
162 default encoding, converting this name to a Unicode object before passing
163 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000164 would attempt to use its default encoding (generally ASCII) rather than
165 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000166
Tim Petersa814db52001-05-14 07:05:58 +0000167 In general, this change simply removes surprises when working with
168 Unicode and the file system, making these operations work as you expect,
169 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000170 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000171
Tim Peters61dff2b2001-05-08 15:43:37 +0000172- Float (and complex) literals in source code were evaluated to full
173 precision only when running from a .py file; the same code loaded from a
174 .pyc (or .pyo) file could suffer numeric differences starting at about the
175 12th significant decimal digit. For example, on a machine with IEEE-754
176 floating arithmetic,
177
178 x = 9007199254740992.0
179 print long(x)
180
181 printed 9007199254740992 if run directly from .py, but 9007199254740000
182 if from a compiled (.pyc or .pyo) file. This was due to marshal using
183 str(float) instead of repr(float) when building code objects. marshal
184 now uses repr(float) instead, which should reproduce floats to full
185 machine precision (assuming the platform C float<->string I/O conversion
186 functions are of good quality).
187
188 This may cause floating-point results to change in some cases, and
189 usually for the better, but may also cause numerically unstable
190 algorithms to break.
191
Tim Peters2f228e72001-05-13 00:19:31 +0000192- The implementation of dicts suffers fewer collisions, which has speed
193 benefits. However, the order in which dict entries appear in dict.keys(),
194 dict.values() and dict.items() may differ from previous releases for a
195 given dict. Nothing is defined about this order, so no program should
196 rely on it. Nevertheless, it's easy to write test cases that rely on the
197 order by accident, typically because of printing the str() or repr() of a
198 dict to an "expected results" file. See Lib/test/test_support.py's new
199 sortdict(dict) function for a simple way to display a dict in sorted
200 order.
201
Tim Peters7a3bfc32001-06-12 01:22:22 +0000202- Many other small changes to dicts were made, resulting in faster
203 operation along the most common code paths.
204
Guido van Rossum10315822001-05-01 20:54:30 +0000205- Dictionary objects now support the "in" operator: "x in dict" means
206 the same as dict.has_key(x).
207
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000208- The update() method of dictionaries now accepts generic mapping
209 objects. Specifically the argument object must support the .keys()
210 and __getitem__() methods. This allows you to say, for example,
211 {}.update(UserDict())
212
Guido van Rossum10315822001-05-01 20:54:30 +0000213- Iterators were added; this is a generalized way of providing values
214 to a for loop. See PEP 234. There's a new built-in function iter()
215 to return an iterator. There's a new protocol to get the next value
216 from an iterator using the next() method (in Python) or the
217 tp_iternext slot (in C). There's a new protocol to get iterators
218 using the __iter__() method (in Python) or the tp_iter slot (in C).
219 Iterating (i.e. a for loop) over a dictionary generates its keys.
220 Iterating over a file generates its lines.
221
Tim Petersf553f892001-05-01 20:45:31 +0000222- The following functions were generalized to work nicely with iterator
223 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000224 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000225 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
226 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000227 join() method of strings
228 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000229 'x in y' and 'x not in y' (PySequence_Contains() in C API)
230 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000231 right-hand side of assignment statements with multiple targets, such as
232 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000233
Tim Petersd85e1022001-05-11 21:51:48 +0000234- Accessing module attributes is significantly faster (for example,
235 random.random or os.path or yourPythonModule.yourAttribute).
236
Tim Peterse63415e2001-05-08 04:38:29 +0000237- Comparing dictionary objects via == and != is faster, and now works even
238 if the keys and values don't support comparisons other than ==.
239
Tim Peters95bf9392001-05-10 08:32:44 +0000240- Comparing dictionaries in ways other than == and != is slower: there were
241 insecurities in the dict comparison implementation that could cause Python
242 to crash if the element comparison routines for the dict keys and/or
243 values mutated the dicts. Making the code bulletproof slowed it down.
244
Tim Peterseb28ef22001-06-02 05:27:19 +0000245- Collisions in dicts are resolved via a new approach, which can help
246 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000247 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000248 faster now. Thanks to Christian Tismer for pointing out the cause and
249 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000250
Tim Peters52e155e2001-06-16 05:42:57 +0000251- repr() is much faster for large containers (dict, list, tuple).
252
253
Tim Petersa814db52001-05-14 07:05:58 +0000254Library
255
Fred Drake960fdf92001-07-20 18:38:26 +0000256- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
257 were added to the string module. These a locale-indenpendent
258 constants, unlike letters, lowercase, and uppercase. These are now
259 use in appropriate locations in the standard library.
260
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000261- The flags used in dlopen calls can now be configured using
262 sys.setdlopenflags and queried using sys.getdlopenflags.
263
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000264- Fredrik Lundh's xmlrpclib is now a standard library module. This
265 provides full client-side XML-RPC support. In addition,
266 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
267 one asyncore-based). Thanks to Eric Raymond for the documentation.
268
Guido van Rossum643d3912001-07-05 14:46:25 +0000269- The xrange() object is simplified: it no longer supports slicing,
270 repetition, comparisons, efficient 'in' checking, the tolist()
271 method, or the start, stop and step attributes. See PEP 260.
272
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000273- A new function fnmatch.filter to filter lists of file names was added.
274
Barry Warsawffd674d2001-05-22 16:00:10 +0000275- calendar.py uses month and day names based on the current locale.
276
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000277- strop is now *really* obsolete (this was announced before with 1.6),
278 and issues DeprecationWarning when used (except for the four items
279 that are still imported into string.py).
280
Tim Petersa814db52001-05-14 07:05:58 +0000281- Cookie.py now sorts key+value pairs by key in output strings.
282
283- pprint.isrecursive(object) didn't correctly identify recursive objects.
284 Now it does.
285
Tim Peters95b3f782001-05-14 18:39:41 +0000286- pprint functions now much faster for large containers (tuple, list, dict).
287
Tim Peters7b9542a2001-06-10 23:40:19 +0000288- New 'q' and 'Q' format codes in the struct module, corresponding to C
289 types "long long" and "unsigned long long" (on Windows, __int64). In
290 native mode, these can be used only when the platform C compiler supports
291 these types (when HAVE_LONG_LONG is #define'd by the Python config
292 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000293 In standard mode, 'q' and 'Q' are supported on all platforms, and are
294 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000295
Guido van Rossum83213cc2001-06-12 16:48:52 +0000296- The site module installs a new built-in function 'help' that invokes
297 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
298 it displays a message reminding the user to use 'help()' or
299 'help(object)'.
300
Tim Petersa814db52001-05-14 07:05:58 +0000301Tests
302
303- New test_mutants.py runs dict comparisons where the key and value
304 comparison operators mutute the dicts randomly during comparison. This
305 rapidly causes Python to crash under earlier releases (not for the faint
306 of heart: it can also cause Win9x to freeze or reboot!).
307
308- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000309 pprint.isreadable() return sensible results. Also verifies that simple
310 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000311
Tim Peters58e0a8c2001-05-14 22:32:33 +0000312New platforms
313
314- Python should compile and run out of the box using the Borland C
315 compiler (under Windows), thanks to Stephen Hansen.
Tim Petersf553f892001-05-01 20:45:31 +0000316
Tim Peters4324aa32001-05-28 22:30:08 +0000317C API
318
319- Removed the unused last_is_sticky argument from the internal
320 _PyTuple_Resize(). If this affects you, you were cheating.
321
322
Guido van Rossum55a78992001-07-17 17:22:32 +0000323======================================================================
324
325
Guido van Rossumffe13be2001-04-16 18:46:45 +0000326What's New in Python 2.1 (final)?
327=================================
328
329We only changed a few things since the last release candidate, all in
330Python library code:
331
332- A bug in the locale module was fixed that affected locales which
333 define no grouping for numeric formatting.
334
335- A few bugs in the weakref module's implementations of weak
336 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
337 and the test suite was updated to check for these bugs.
338
339- An old bug in the os.path.walk() function (introduced in Python
340 2.0!) was fixed: a non-existent file would cause an exception
341 instead of being ignored.
342
343- Fixed a few bugs in the new symtable module found by Neil Norwitz's
344 PyChecker.
345
346
Guido van Rossum5b08f132001-04-16 02:05:23 +0000347What's New in Python 2.1c2?
348===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000349
Guido van Rossum5b08f132001-04-16 02:05:23 +0000350A flurry of small changes, and one showstopper fixed in the nick of
351time made it necessary to release another release candidate. The list
352here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000353
Guido van Rossum5b08f132001-04-16 02:05:23 +0000354Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000355
Guido van Rossum5b08f132001-04-16 02:05:23 +0000356- Tim discovered a nasty bug in the dictionary code, caused by
357 PyDict_Next() calling dict_resize(), and the GC code's use of
358 PyDict_Next() violating an assumption in dict_items(). This was
359 fixed with considerable amounts of band-aid, but the net effect is a
360 saner and more robust implementation.
361
362- Made a bunch of symbols static that were accidentally global.
363
364Build and Ports
365
366- The setup.py script didn't check for a new enough version of zlib
367 (1.1.3 is needed). Now it does.
368
369- Changed "make clean" target to also remove shared libraries.
370
371- Added a more general warning about the SGI Irix optimizer to README.
372
373Library
374
375- Fix a bug in urllib.basejoin("http://host", "../file.html") which
376 omitted the slash between host and file.html.
377
378- The mailbox module's _Mailbox class contained a completely broken
379 and undocumented seek() method. Ripped it out.
380
381- Fixed a bunch of typos in various library modules (urllib2, smtpd,
382 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
383
384- Fixed a few last-minute bugs in unittest.
385
386Extensions
387
388- Reverted the patch to the OpenSSL code in socketmodule.c to support
389 RAND_status() and the EGD, and the subsequent patch that tried to
390 fix it for pre-0.9.5 versions; the problem with the patch is that on
391 some systems it issues a warning whenever socket is imported, and
392 that's unacceptable.
393
394Tests
395
396- Fixed the pickle tests to work with "import test.test_pickle".
397
398- Tweaked test_locale.py to actually run the test Windows.
399
400- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
401 not "wb" (which is not a valid mode at all).
402
403- Fix pstats browser crashes. Import readline if it exists to make
404 the user interface nicer.
405
406- Add "import thread" to the top of test modules that import the
407 threading module (test_asynchat and test_threadedtempfile). This
408 prevents test failures caused by a broken threading module resulting
409 from a previously caught failed import.
410
411- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
412 needed on some platforms (e.g. Solaris 8) when the tests are run
413 twice in succession.
414
415- Skip rather than fail test_sunaudiodev if no audio device is found.
416
417
418What's New in Python 2.1c1?
419===========================
420
421This list was significantly updated when 2.1c2 was released; the 2.1c1
422release didn't mention most changes that were actually part of 2.1c1:
423
424Legal
425
426- Copyright was assigned to the Python Software Foundation (PSF) and a
427 PSF license (very similar to the CNRI license) was added.
428
429- The CNRI copyright notice was updated to include 2001.
430
431Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000432
Guido van Rossumc9932722001-04-12 02:31:27 +0000433- After a public outcry, assignment to __debug__ is no longer illegal;
434 instead, a warning is issued. It will become illegal in 2.2.
435
Guido van Rossum5b08f132001-04-16 02:05:23 +0000436- Fixed a core dump with "%#x" % 0, and changed the semantics so that
437 "%#x" now always prepends "0x", even if the value is zero.
438
439- Fixed some nits in the bytecode compiler.
440
441- Fixed core dumps when calling certain kinds of non-functions.
442
443- Fixed various core dumps caused by reference count bugs.
444
445Build and Ports
446
447- Use INSTALL_SCRIPT to install script files.
448
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000449- New port: SCO Unixware 7, by Billy G. Allie.
450
Guido van Rossum5b08f132001-04-16 02:05:23 +0000451- Updated RISCOS port.
452
453- Updated BeOS port and notes.
454
455- Various other porting problems resolved.
456
457Library
458
459- The TERMIOS and SOCKET modules are now truly obsolete and
460 unnecessary. Their symbols are incorporated in the termios and
461 socket modules.
462
463- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
464 better tests for pickling.
465
466- threading: make Condition.wait() robust against KeyboardInterrupt.
467
468- zipfile: add support to zipfile to support opening an archive
469 represented by an open file rather than a file name. Fix bug where
470 the archive was not properly closed. Fixed a bug in this bugfix
471 where flush() was called for a read-only file.
472
473- imputil: added an uninstall() method to the ImportManager.
474
475- Canvas: fixed bugs in lower() and tkraise() methods.
476
477- SocketServer: API change (added overridable close_request() method)
478 so that the TCP server can explicitly close the request.
479
480- pstats: Eric Raymond added a simple interactive statistics browser,
481 invoked when the module is run as a script.
482
483- locale: fixed a problem in format().
484
485- webbrowser: made it work when the BROWSER environment variable has a
486 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
487 KDE 2. Fixed some other nits.
488
489- unittest: changes to allow using a different exception than
490 AssertionError, and added a few more function aliases. Some other
491 small changes.
492
493- urllib, urllib2: fixed redirect problems and a coupleof other nits.
494
495- asynchat: fixed a critical bug in asynchat that slipped through the
496 2.1b2 release. Fixed another rare bug.
497
498- Fix some unqualified except: clauses (always a bad code example).
499
500XML
501
502- pyexpat: new API get_version_string().
503
504- Fixed some minidom bugs.
505
506Extensions
507
508- Fixed a core dump in _weakref. Removed the weakref.mapping()
509 function (it adds nothing to the API).
510
511- Rationalized the use of header files in the readline module, to make
512 it compile (albeit with some warnings) with the very recent readline
513 4.2, without breaking for earlier versions.
514
515- Hopefully fixed a buffering problem in linuxaudiodev.
516
517- Attempted a fix to make the OpenSSL support in the socket module
518 work again with pre-0.9.5 versions of OpenSSL.
519
520Tests
521
522- Added a test case for asynchat and asyncore.
523
524- Removed coupling between tests where one test failing could break
525 another.
526
527Tools
528
529- Ping added an interactive help browser to pydoc, fixed some nits
530 in the rest of the pydoc code, and added some features to his
531 inspect module.
532
533- An updated python-mode.el version 4.1 which integrates Ken
534 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
535 much nicer in XEmacs and Emacs. When stepping through your program
536 with pdb, in either the shell window or the *Python* window, the
537 source file and line will be tracked by an arrow. Very cool!
538
539- IDLE: syntax warnings in interactive mode are changed into errors.
540
541- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +0000542 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +0000543
544- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000545
Barry Warsaw11e89c72001-04-11 20:37:57 +0000546
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000547What's New in Python 2.1 beta 2?
548================================
549
Guido van Rossum053ae352001-03-22 14:17:21 +0000550(Unlisted are many fixed bugs, more documentation, etc.)
551
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000552Core language, builtins, and interpreter
553
Guido van Rossum053ae352001-03-22 14:17:21 +0000554- The nested scopes work (enabled by "from __future__ import
555 nested_scopes") is completed; in particular, the future now extends
556 into code executed through exec, eval() and execfile(), and into the
557 interactive interpreter.
558
559- When calling a base class method (e.g. BaseClass.__init__(self)),
560 this is now allowed even if self is not strictly spoken a class
561 instance (e.g. when using metaclasses or the Don Beaudry hook).
562
563- Slice objects are now comparable but not hashable; this prevents
564 dict[:] from being accepted but meaningless.
565
566- Complex division is now calculated using less braindead algorithms.
567 This doesn't change semantics except it's more likely to give useful
568 results in extreme cases. Complex repr() now uses full precision
569 like float repr().
570
571- sgmllib.py now calls handle_decl() for simple <!...> declarations.
572
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000573- It is illegal to assign to the name __debug__, which is set when the
574 interpreter starts. It is effectively a compile-time constant.
575
576- A warning will be issued if a global statement for a variable
577 follows a use or assignment of that variable.
578
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000579Standard library
580
Guido van Rossum053ae352001-03-22 14:17:21 +0000581- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
582 inspired by JUnit), is now part of the standard library. You now
583 have a choice of two testing frameworks: unittest requires you to
584 write testcases as separate code, doctest gathers them from
585 docstrings. Both approaches have their advantages and
586 disadvantages.
587
588- A new module Tix was added, which wraps the Tix extension library
589 for Tk. With that module, it is not necessary to statically link
590 Tix with _tkinter, since Tix will be loaded with Tcl's "package
591 require" command. See Demo/tix/.
592
593- tzparse.py is now obsolete.
594
595- In gzip.py, the seek() and tell() methods are removed -- they were
596 non-functional anyway, and it's better if callers can test for their
597 existence with hasattr().
598
599Python/C API
600
601- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
602 that's already in the dictionary during a PyDict_Next() iteration.
603 This used to fail occasionally when a dictionary resize operation
604 could be triggered that would rehash all the keys. All other
605 modifications to the dictionary are still off-limits during a
606 PyDict_Next() iteration!
607
608- New extended APIs related to passing compiler variables around.
609
610- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
611 implement isinstance() and issubclass().
612
613- Py_BuildValue() now has a "D" conversion to create a Python complex
614 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000615
Fred Drake4e262a92001-03-22 18:26:47 +0000616- Extensions types which support weak references must now set the
617 field allocated for the weak reference machinery to NULL themselves;
618 this is done to avoid the cost of checking each object for having a
619 weakly referencable type in PyObject_INIT(), since most types are
620 not weakly referencable.
621
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000622- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
623 free variables and cell variables to and from the frame's f_locals.
624
625- Variants of several functions defined in pythonrun.h have been added
626 to support the nested_scopes future statement. The variants all end
627 in Flags and take an extra argument, a PyCompilerFlags *; examples:
628 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
629 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +0000630 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000631
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000632Distutils
633
634- the sdist command now writes a PKG-INFO file, as described in PEP 241,
635 into the release tree.
636
Tim Peters0e57abf2001-05-02 07:39:38 +0000637- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000638 (an uninstaller, more customization of the installer's display)
639
640- from Jack Jansen: added Mac-specific code to generate a dialog for
641 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +0000642 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000643 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +0000644
645- added 'platforms' and 'keywords' to the set of metadata that can be
646 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000647
648- applied patches from Jason Tishler to make the compiler class work with
649 Cygwin.
650
651
Tim Peters2fe289a2001-03-01 22:19:38 +0000652What's New in Python 2.1 beta 1?
653================================
Tim Petersd66595f2001-02-04 03:09:53 +0000654
655Core language, builtins, and interpreter
656
Guido van Rossum9d0fbde2001-03-02 14:00:32 +0000657- Following an outcry from the community about the amount of code
658 broken by the nested scopes feature introduced in 2.1a2, we decided
659 to make this feature optional, and to wait until Python 2.2 (or at
660 least 6 months) to make it standard. The option can be enabled on a
661 per-module basis by adding "from __future__ import nested_scopes" at
662 the beginning of a module (before any other statements, but after
663 comments and an optional docstring). See PEP 236 (Back to the
664 __future__) for a description of the __future__ statement. PEP 227
665 (Statically Nested Scopes) has been updated to reflect this change,
666 and to clarify the semantics in a number of endcases.
667
668- The nested scopes code, when enabled, has been hardened, and most
669 bugs and memory leaks in it have been fixed.
670
671- Compile-time warnings are now generated for a number of conditions
672 that will break or change in meaning when nested scopes are enabled:
673
674 - Using "from...import *" or "exec" without in-clause in a function
675 scope that also defines a lambda or nested function with one or
676 more free (non-local) variables. The presence of the import* or
677 bare exec makes it impossible for the compiler to determine the
678 exact set of local variables in the outer scope, which makes it
679 impossible to determine the bindings for free variables in the
680 inner scope. To avoid the warning about import *, change it into
681 an import of explicitly name object, or move the import* statement
682 to the global scope; to avoid the warning about bare exec, use
683 exec...in... (a good idea anyway -- there's a possibility that
684 bare exec will be deprecated in the future).
685
686 - Use of a global variable in a nested scope with the same name as a
687 local variable in a surrounding scope. This will change in
688 meaning with nested scopes: the name in the inner scope will
689 reference the variable in the outer scope rather than the global
690 of the same name. To avoid the warning, either rename the outer
691 variable, or use a global statement in the inner function.
692
Neil Schemenauera35c6882001-02-27 04:45:05 +0000693- An optional object allocator has been included. This allocator is
694 optimized for Python objects and should be faster and use less memory
695 than the standard system allocator. It is not enabled by default
696 because of possible thread safety problems. The allocator is only
697 protected by the Python interpreter lock and it is possible that some
698 extension modules require a thread safe allocator. The object
699 allocator can be enabled by providing the "--with-pymalloc" option to
700 configure.
701
Tim Petersd66595f2001-02-04 03:09:53 +0000702Standard library
703
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000704- pyexpat now detects the expat version if expat.h defines it. A
705 number of additional handlers are provided, which are only available
706 since expat 1.95. In addition, the methods SetParamEntityParsing and
707 GetInputContext of Parser objects are available with 1.95.x
708 only. Parser objects now provide the ordered_attributes and
709 specified_attributes attributes. A new module expat.model was added,
710 which offers a number of additional constants if 1.95.x is used.
711
712- xml.dom offers the new functions registerDOMImplementation and
713 getDOMImplementation.
714
715- xml.dom.minidom offers a toprettyxml method. A number of DOM
716 conformance issues have been resolved. In particular, Element now
717 has an hasAttributes method, and the handling of namespaces was
718 improved.
719
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000720- Ka-Ping Yee contributed two new modules: inspect.py, a module for
721 getting information about live Python code, and pydoc.py, a module
722 for interactively converting docstrings to HTML or text.
723 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +0000724 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +0000725 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
726 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000727
Tim Peters1eff7962001-03-01 02:31:33 +0000728- New library module difflib.py, primarily packaging the SequenceMatcher
729 class at the heart of the popular ndiff.py file-comparison tool.
730
731- doctest.py (a framework for verifying Python code examples in docstrings)
732 is now part of the std library.
733
Tim Petersd66595f2001-02-04 03:09:53 +0000734Windows changes
735
Guido van Rossume3955a82001-03-02 14:05:59 +0000736- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
737 small GUI that lets you browse the module docstrings using your
738 default web browser.
739
Tim Peters1eff7962001-03-01 02:31:33 +0000740- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
741 Platforms) is implemented. See
742
743 http://python.sourceforge.net/peps/pep-0235.html
744
745 for full details, especially the "Current Lower-Left Semantics" section.
746 The new Windows import rules are simpler than before:
747
748 A. If the PYTHONCASEOK environment variable exists, same as
749 before: silently accept the first case-insensitive match of any
750 kind; raise ImportError if none found.
751
752 B. Else search sys.path for the first case-sensitive match; raise
753 ImportError if none found.
754
755 The same rules have been implented on other platforms with case-
756 insensitive but case-preserving filesystems too (including Cygwin, and
757 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +0000758
Tim Peters25a9ce32001-02-19 07:06:36 +0000759- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
760 what it's supposed to do (and does do under NT and 2000) via direct
761 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +0000762 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +0000763 all Win9x systems before.
764
Tim Peters1eff7962001-03-01 02:31:33 +0000765- Build: Subproject _test (effectively) renamed to _testcapi.
766
Tim Peters2fe289a2001-03-01 22:19:38 +0000767New platforms
768
769- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
770 Thanks to Steven Majewski!
771
772- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
773 Tishler!
774
Guido van Rossum9089b272001-03-02 06:49:50 +0000775- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
776 Schwertberger! See RISCOS/README for more information -- it seems
777 that because of the bizarre filename conventions on RISCOS, no port
778 to that platform is easy. Note that the new variable os.endsep is
779 silently supported in order to make life easier on this platform,
780 but we don't advertise it because it's not worth for most folks to
781 care about RISCOS portability.
782
Tim Peters25a9ce32001-02-19 07:06:36 +0000783
Tim Petersd7b5e882001-01-25 03:36:26 +0000784What's New in Python 2.1 alpha 2?
785=================================
Tim Peters40ead762001-01-27 05:35:26 +0000786
Tim Petersd7b5e882001-01-25 03:36:26 +0000787Core language, builtins, and interpreter
788
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000789- Scopes nest. If a name is used in a function or class, but is not
790 local, the definition in the nearest enclosing function scope will
791 be used. One consequence of this change is that lambda statements
792 could reference variables in the namespaces where the lambda is
793 defined. In some unusual cases, this change will break code.
794
795 In all previous version of Python, names were resolved in exactly
796 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000797 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000798 function A is defined within a function B, the names bound in B are
799 not visible in A. The new rules make names bound in B visible in A,
800 unless A contains a name binding that hides the binding in B.
801
802 Section 4.1 of the reference manual describes the new scoping rules
803 in detail. The test script in Lib/test/test_scope.py demonstrates
804 some of the effects of the change.
805
806 The new rules will cause existing code to break if it defines nested
807 functions where an outer function has local variables with the same
808 name as globals or builtins used by the inner function. Example:
809
810 def munge(str):
811 def helper(x):
812 return str(x)
813 if type(str) != type(''):
814 str = helper(str)
815 return str.strip()
816
817 Under the old rules, the name str in helper() is bound to the
818 builtin function str(). Under the new rules, it will be bound to
819 the argument named str and an error will occur when helper() is
820 called.
821
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000822- The compiler will report a SyntaxError if "from ... import *" occurs
823 in a function or class scope. The language reference has documented
824 that this case is illegal, but the compiler never checked for it.
825 The recent introduction of nested scope makes the meaning of this
826 form of name binding ambiguous. In a future release, the compiler
827 may allow this form when there is no possibility of ambiguity.
828
Tim Peters40ead762001-01-27 05:35:26 +0000829- repr(string) is easier to read, now using hex escapes instead of octal,
830 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
831
832 >>> "\texample \r\n" + chr(0) + chr(255)
833 '\texample \r\n\x00\xff' # in 2.1
834 '\011example \015\012\000\377' # in 2.0
835
Moshe Zadka6af0ce02001-01-29 06:41:00 +0000836- Functions are now compared and hashed by identity, not by value, since
837 the func_code attribute is writable.
838
Fred Drakefb9d7122001-02-01 20:00:40 +0000839- Weak references (PEP 205) have been added. This involves a few
840 changes in the core, an extension module (_weakref), and a Python
841 module (weakref). The weakref module is the public interface. It
842 includes support for "explicit" weak references, proxy objects, and
843 mappings with weakly held values.
844
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000845- A 'continue' statement can now appear in a try block within the body
846 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +0000847 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000848
Tim Petersd7b5e882001-01-25 03:36:26 +0000849Standard library
850
Barry Warsaw30dbd142001-01-31 22:14:01 +0000851- mailbox.py now has a new class, PortableUnixMailbox which is
852 identical to UnixMailbox but uses a more portable scheme for
853 determining From_ separators. Also, the constructors for all the
854 classes in this module have a new optional `factory' argument, which
855 is a callable used when new message classes must be instantiated by
856 the next() method.
857
Tim Petersd7b5e882001-01-25 03:36:26 +0000858- random.py is now self-contained, and offers all the functionality of
859 the now-deprecated whrandom.py. See the docs for details. random.py
860 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +0000861 and restoring the internal state of the generator; and jumpahead(n),
862 for quickly forcing the internal state to be the same as if n calls to
863 random() had been made. The latter is particularly useful for multi-
864 threaded programs, creating one instance of the random.Random() class for
865 each thread, then using .jumpahead() to force each instance to use a
866 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +0000867
Tim Peters0de88fc2001-02-01 04:59:18 +0000868- random.py's seed() function is new. For bit-for-bit compatibility with
869 prior releases, use the whseed function instead. The new seed function
870 addresses two problems: (1) The old function couldn't produce more than
871 about 2**24 distinct internal states; the new one about 2**45 (the best
872 that can be done in the Wichmann-Hill generator). (2) The old function
873 sometimes produced identical internal states when passed distinct
874 integers, and there was no simple way to predict when that would happen;
875 the new one guarantees to produce distinct internal states for all
876 arguments in [0, 27814431486576L).
877
Jeremy Hylton4c4fda02001-02-02 03:29:24 +0000878- The socket module now supports raw packets on Linux. The socket
879 family is AF_PACKET.
880
Tim Peters9ea17ac2001-02-02 05:57:15 +0000881- test_capi.py is a start at running tests of the Python C API. The tests
882 are implemented by the new Modules/_testmodule.c.
883
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000884- A new extension module, _symtable, provides provisional access to the
885 internal symbol table used by the Python compiler. A higher-level
886 interface will be added on top of _symtable in a future release.
887
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +0000888- Removed the obsolete soundex module.
889
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000890- xml.dom.minidom now uses the standard DOM exceptions. Node supports
891 the isSameNode method; NamedNodeMap the get method.
892
893- xml.sax.expatreader supports the lexical handler property; it
894 generates comment, startCDATA, and endCDATA events.
895
Tim Petersee826f82001-01-31 19:39:44 +0000896Windows changes
897
898- Build procedure: the zlib project is built in a different way that
899 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +0000900 the zlib binary used. See PCbuild\readme.txt for details. Your old
901 zlib-related directories can be deleted; you'll need to download fresh
902 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +0000903
Tim Peters9ea17ac2001-02-02 05:57:15 +0000904- Build: New subproject _test for the benefit of test_capi.py (see above).
905
Tim Petersb16c56f2001-02-02 21:24:51 +0000906- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
907 interface to some Python compiler internals).
908
909- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +0000910 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +0000911
Tim Petersa3a3a032000-11-30 05:22:44 +0000912What's New in Python 2.1 alpha 1?
913=================================
914
915Core language, builtins, and interpreter
916
Marc-André Lemburgebb195b2001-01-20 10:34:52 +0000917- There is a new Unicode companion to the PyObject_Str() API
918 called PyObject_Unicode(). It behaves in the same way as the
919 former, but assures that the returned value is an Unicode object
920 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +0000921
Guido van Rossumf98eda02001-01-17 15:54:45 +0000922- The comparison operators support "rich comparison overloading" (PEP
923 207). C extension types can provide a rich comparison function in
924 the new tp_richcompare slot in the type object. The cmp() function
925 and the C function PyObject_Compare() first try the new rich
926 comparison operators before trying the old 3-way comparison. There
927 is also a new C API PyObject_RichCompare() (which also falls back on
928 the old 3-way comparison, but does not constrain the outcome of the
929 rich comparison to a Boolean result).
930
931 The rich comparison function takes two objects (at least one of
932 which is guaranteed to have the type that provided the function) and
933 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
934 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
935 object, which may be NotImplemented (in which case the tp_compare
936 slot function is used as a fallback, if defined).
937
938 Classes can overload individual comparison operators by defining one
939 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +0000940 __ge__. There are no explicit "reflected argument" versions of
941 these; instead, __lt__ and __gt__ are each other's reflection,
942 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
943 reflection (similar at the C level). No other implications are
944 made; in particular, Python does not assume that == is the Boolean
945 inverse of !=, or that < is the Boolean inverse of >=. This makes
946 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +0000947
948 Classes or types that want to implement (in)equality tests but not
949 the ordering operators (i.e. unordered types) should implement ==
950 and !=, and raise an error for the ordering operators.
951
Guido van Rossuma88479f2001-01-18 14:28:08 +0000952 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +0000953 Boolean; e.g. a matrix type might want to return a matrix of bits
954 for A < B, giving elementwise comparisons. Such types should ensure
955 that any interpretation of their value in a Boolean context raises
956 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
957 at the C level) to always raise an exception.
958
Guido van Rossuma88479f2001-01-18 14:28:08 +0000959- Complex numbers use rich comparisons to define == and != but raise
960 an exception for <, <=, > and >=. Unfortunately, this also means
961 that cmp() of two complex numbers raises an exception when the two
962 numbers differ. Since it is not mathematically meaningful to compare
963 complex numbers except for equality, I hope that this doesn't break
964 too much code.
965
Tim Peters3389f192001-02-18 08:48:49 +0000966- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +0000967 not defined by the language, other than that it's arbitrary but
968 consistent (see the Reference Manual). An implementation detail changed
969 in 2.1a1 such that None now compares less than any other object. Code
970 relying on this new behavior (like code that relied on the previous
971 behavior) does so at its own risk.
972
Barry Warsaw573b5412001-01-15 20:43:18 +0000973- Functions and methods now support getting and setting arbitrarily
974 named attributes (PEP 232). Functions have a new __dict__
975 (a.k.a. func_dict) which hold the function attributes. Methods get
976 and set attributes on their underlying im_func. It is a TypeError
977 to set an attribute on a bound method.
978
Guido van Rossum051e3352001-01-15 19:11:10 +0000979- The xrange() object implementation has been improved so that
980 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
981 limitation that in this case len(xrange(sys.maxint)) can't be
982 calculated, but the common idiom "for i in xrange(sys.maxint)" will
983 work fine as long as the index i doesn't actually reach 2**31.
984 (Python uses regular ints for sequence and string indices; fixing
985 that is much more work.)
986
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000987- Two changes to from...import:
988
Guido van Rossumba381232001-02-03 15:06:40 +0000989 1) "from M import X" now works even if (after loading module M)
990 sys.modules['M'] is not a real module; it's basically a getattr()
991 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000992
993 2) "from M import *" now looks for M.__all__ to decide which names to
994 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
995 filters out names starting with '_' as before. Whether or not
996 __all__ exists, there's no restriction on the type of M.
997
Guido van Rossumf61f1662001-01-10 20:13:55 +0000998- File objects have a new method, xreadlines(). This is the fastest
999 way to iterate over all lines in a file:
1000
1001 for line in file.xreadlines():
1002 ...do something to line...
1003
1004 See the xreadlines module (mentioned below) for how to do this for
1005 other file-like objects.
1006
1007- Even if you don't use file.xreadlines(), you may expect a speedup on
1008 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001009 quite a bit in platform-specific ways: on systems (like Linux) that
1010 support flockfile(), getc_unlocked(), and funlockfile(), those are
1011 used by default. On systems (like Windows) without getc_unlocked(),
1012 a complicated (but still thread-safe) method using fgets() is used by
1013 default.
1014
Tim Petersd52269b2001-01-25 06:23:18 +00001015 You can force use of the fgets() method by #define'ing
1016 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001017 getc_unlocked()).
1018
Tim Petersd52269b2001-01-25 06:23:18 +00001019 You can force fgets() not to be used by #define'ing
1020 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001021 test_bufio.py fails -- and let us know if it does!).
1022
1023- In addition, the fileinput module, while still slower than the other
1024 methods on most platforms, has been sped up too, by using
1025 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001026
1027- Support for run-time warnings has been added, including a new
1028 command line option (-W) to specify the disposition of warnings.
1029 See the description of the warnings module below.
1030
1031- Extensive changes have been made to the coercion code. This mostly
1032 affects extension modules (which can now implement mixed-type
1033 numerical operators without having to use coercion), but
1034 occasionally, in boundary cases the coercion semantics have changed
1035 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001036 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001037 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001038 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001039
Guido van Rossumf98eda02001-01-17 15:54:45 +00001040- In connection with the coercion changes, a new built-in singleton
1041 object, NotImplemented is defined. This can be returned for
1042 operations that wish to indicate they are not implemented for a
1043 particular combination of arguments. From C, this is
1044 Py_NotImplemented.
1045
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001046- The interpreter accepts now bytecode files on the command line even
1047 if they do not have a .pyc or .pyo extension. On Linux, after executing
1048
Martin v. Löwise214baa2001-02-04 22:37:56 +00001049import imp,sys,string
1050magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1051reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1052open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001053
1054 any byte code file can be used as an executable (i.e. as an argument
1055 to execve(2)).
1056
Tim Peters9940b802000-12-01 07:59:35 +00001057- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001058 character. In 1.6 and earlier, they never produced a sign,
1059 and raised an error if the value of the long was too large
1060 to fit in a Python int. In 2.0, they produced a sign if and
1061 only if too large to fit in an int. This was inconsistent
1062 across platforms (because the size of an int varies across
1063 platforms), and inconsistent with hex() and oct(). Example:
1064
1065 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001066 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001067 'ffffffbe' # in 2.0 and before, on 32-bit machines
1068 >>> hex(-0x42L)
1069 '-0x42L' # in all versions of Python
1070
Tim Peters9940b802000-12-01 07:59:35 +00001071 The behavior of %d formats for negative Python longs remains
1072 the same as in 2.0 (although in 1.6 and before, they raised
1073 an error if the long didn't fit in a Python int).
1074
1075 %u formats don't make sense for Python longs, but are allowed
1076 and treated the same as %d in 2.1. In 2.0, a negative long
1077 formatted via %u produced a sign if and only if too large to
1078 fit in an int. In 1.6 and earlier, a negative long formatted
1079 via %u raised an error if it was too big to fit in an int.
1080
Guido van Rossum3661d392000-12-12 22:10:31 +00001081- Dictionary objects have an odd new method, popitem(). This removes
1082 an arbitrary item from the dictionary and returns it (in the form of
1083 a (key, value) pair). This can be useful for algorithms that use a
1084 dictionary as a bag of "to do" items and repeatedly need to pick one
1085 item. Such algorithms normally end up running in quadratic time;
1086 using popitem() they can usually be made to run in linear time.
1087
Tim Peters36cdad12000-12-29 02:06:45 +00001088Standard library
1089
Thomas Woutersfe385252001-01-19 23:16:56 +00001090- In the time module, the time argument to the functions strftime,
1091 localtime, gmtime, asctime and ctime is now optional, defaulting to
1092 the current time (in the local timezone).
1093
Guido van Rossumda91f222001-01-15 16:36:08 +00001094- The ftplib module now defaults to passive mode, which is deemed a
1095 more useful default given that clients are often inside firewalls
1096 these days. Note that this could break if ftplib is used to connect
1097 to a *server* that is inside a firewall, from outside; this is
1098 expected to be a very rare situation. To fix that, you can call
1099 ftp.set_pasv(0).
1100
Martin v. Löwis10a27872001-01-13 09:54:41 +00001101- The module site now treats .pth files not only for path configuration,
1102 but also supports extensions to the initialization code: Lines starting
1103 with import are executed.
1104
Guido van Rossumf61f1662001-01-10 20:13:55 +00001105- There's a new module, warnings, which implements a mechanism for
1106 issuing and filtering warnings. There are some new built-in
1107 exceptions that serve as warning categories, and a new command line
1108 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1109 turns warnings into errors). warnings.warn(message[, category])
1110 issues a warning message; this can also be called from C as
1111 PyErr_Warn(category, message).
1112
1113- A new module xreadlines was added. This exports a single factory
1114 function, xreadlines(). The intention is that this code is the
1115 absolutely fastest way to iterate over all lines in an open
1116 file(-like) object:
1117
1118 import xreadlines
1119 for line in xreadlines.xreadlines(file):
1120 ...do something to line...
1121
1122 This is equivalent to the previous the speed record holder using
1123 file.readlines(sizehint). Note that if file is a real file object
1124 (as opposed to a file-like object), this is equivalent:
1125
1126 for line in file.xreadlines():
1127 ...do something to line...
1128
Tim Peters36cdad12000-12-29 02:06:45 +00001129- The bisect module has new functions bisect_left, insort_left,
1130 bisect_right and insort_right. The old names bisect and insort
1131 are now aliases for bisect_right and insort_right. XXX_right
1132 and XXX_left methods differ in what happens when the new element
1133 compares equal to one or more elements already in the list: the
1134 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001135 right. Code that doesn't care where equal elements end up should
1136 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001137
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001138- The new curses.panel module wraps the panel library that forms part
1139 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1140
Guido van Rossumf61f1662001-01-10 20:13:55 +00001141- The SocketServer module now sets the allow_reuse_address flag by
1142 default in the TCPServer class.
1143
1144- A new function, sys._getframe(), returns the stack frame pointer of
1145 the caller. This is intended only as a building block for
1146 higher-level mechanisms such as string interpolation.
1147
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001148- The pyexpat module supports a number of new handlers, which are
1149 available only in expat 1.2. If invocation of a callback fails, it
1150 will report an additional frame in the traceback. Parser objects
1151 participate now in garbage collection. If expat reports an unknown
1152 encoding, pyexpat will try to use a Python codec; that works only
1153 for single-byte charsets. The parser type objects is exposed as
1154 XMLParserObject.
1155
1156- xml.dom now offers standard definitions for symbolic node type and
1157 exception code constants, and a hierarchy of DOM exceptions. minidom
1158 was adjusted to use them.
1159
1160- The conformance of xml.dom.minidom to the DOM specification was
1161 improved. It detects a number of additional error cases; the
1162 previous/next relationship works even when the tree is modified;
1163 Node supports the normalize() method; NamedNodeMap, DocumentType and
1164 DOMImplementation classes were added; Element supports the
1165 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1166 method.
1167
Guido van Rossumf61f1662001-01-10 20:13:55 +00001168Build issues
1169
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001170- For Unix (and Unix-compatible) builds, configuration and building of
1171 extension modules is now greatly automated. Rather than having to
1172 edit the Modules/Setup file to indicate which modules should be
1173 built and where their include files and libraries are, a
1174 distutils-based setup.py script now takes care of building most
1175 extension modules. All extension modules built this way are built
1176 as shared libraries. Only a few modules that must be linked
1177 statically are still listed in the Setup file; you won't need to
1178 edit their configuration.
1179
1180- Python should now build out of the box on Cygwin. If it doesn't,
1181 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001182
1183- Python now always uses its own (renamed) implementation of getopt()
1184 -- there's too much variation among C library getopt()
1185 implementations.
1186
1187- C++ compilers are better supported; the CXX macro is always set to a
1188 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001189
Tim Petersd92dfe02000-12-12 01:18:41 +00001190Windows changes
1191
1192- select module: By default under Windows, a select() call
1193 can specify no more than 64 sockets. Python now boosts
1194 this Microsoft default to 512. If you need even more than
1195 that, see the MS docs (you'll need to #define FD_SETSIZE
1196 and recompile Python from source).
1197
Guido van Rossumf61f1662001-01-10 20:13:55 +00001198- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1199 subdirectory is no more!
1200
Tim Petersa3a3a032000-11-30 05:22:44 +00001201
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001202What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001203=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001204
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001205Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001206changes are in the file HISTORY. If you are making the jump directly
1207from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1208HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001209
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001210Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1211the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1212http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001213
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001214--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001215
1216======================================================================
1217
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001218What's new in 2.0 (since release candidate 1)?
1219==============================================
1220
1221Standard library
1222
1223- The copy_reg module was modified to clarify its intended use: to
1224 register pickle support for extension types, not for classes.
1225 pickle() will raise a TypeError if it is passed a class.
1226
1227- Fixed a bug in gettext's "normalize and expand" code that prevented
1228 it from finding an existing .mo file.
1229
1230- Restored support for HTTP/0.9 servers in httplib.
1231
Tim Peters989b7b92000-10-16 20:24:53 +00001232- The math module was changed to stop raising OverflowError in case of
1233 underflow, and return 0 instead in underflow cases. Whether Python
1234 used to raise OverflowError in case of underflow was platform-
1235 dependent (it did when the platform math library set errno to ERANGE
1236 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001237
1238- Fixed a bug in StringIO that occurred when the file position was not
1239 at the end of the file and write() was called with enough data to
1240 extend past the end of the file.
1241
1242- Fixed a bug that caused Tkinter error messages to get lost on
1243 Windows. The bug was fixed by replacing direct use of
1244 interp->result with Tcl_GetStringResult(interp).
1245
1246- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1247 redirect response.
1248
1249- Several changes were made to distutils: Some debugging code was
1250 removed from util. Fixed the installer used when an external zip
1251 program (like WinZip) is not found; the source code for this
1252 installer is in Misc/distutils. check_lib() was modified to behave
1253 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1254 test for whether installed modules are on sys.path was changed to
1255 use both normcase() and normpath().
1256
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001257- Several minor bugs were fixed in the xml package (the minidom,
1258 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001259
1260- The regression test driver (regrtest.py) behavior when invoked with
1261 -l changed: It now reports a count of objects that are recognized as
1262 garbage but not freed by the garbage collector.
1263
Tim Peters989b7b92000-10-16 20:24:53 +00001264- The regression test for the math module was changed to test
1265 exceptional behavior when the test is run in verbose mode. Python
1266 cannot yet guarantee consistent exception behavior across platforms,
1267 so the exception part of test_math is run only in verbose mode, and
1268 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001269
1270Internals
1271
1272- PyOS_CheckStack() has been disabled on Win64, where it caused
1273 test_sre to fail.
1274
1275Build issues
1276
1277- Changed compiler flags, so that gcc is always invoked with -Wall and
1278 -Wstrict-prototypes. Users compiling Python with GCC should see
1279 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001280 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001281 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001282
Tim Petersa3a3a032000-11-30 05:22:44 +00001283- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001284
1285Tools and other miscellany
1286
1287- The compiler in Tools/compiler was updated to support the new
1288 language features introduced in 2.0: extended print statement, list
1289 comprehensions, and augmented assignments. The new compiler should
1290 also be backwards compatible with Python 1.5.2; the compiler will
1291 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001292 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001293
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001294What's new in 2.0 release candidate 1 (since beta 2)?
1295=====================================================
1296
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001297What is release candidate 1?
1298
1299We believe that release candidate 1 will fix all known bugs that we
1300intend to fix for the 2.0 final release. This release should be a bit
1301more stable than the previous betas. We would like to see even more
1302widespread testing before the final release, so we are producing this
1303release candidate. The final release will be exactly the same unless
1304any show-stopping (or brown bag) bugs are found by testers of the
1305release candidate.
1306
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001307All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001308to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001309
1310Core language, builtins, and interpreter
1311
1312- A bug that caused crashes when __coerce__ was used with augmented
1313 assignment, e.g. +=, was fixed.
1314
1315- Raise ZeroDivisionError when raising zero to a negative number,
1316 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1317 power operator and the result of math.pow(0.0, -2.0) will vary by
1318 platform. On Linux, it raises a ValueError.
1319
1320- A bug in Unicode string interpolation was fixed that occasionally
1321 caused errors with formats including "%%". For example, the
1322 following expression "%% %s" % u"abc" no longer raises a TypeError.
1323
1324- Compilation of deeply nested expressions raises MemoryError instead
1325 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1326
1327- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1328 rendering them useless. They are now written in binary mode again.
1329
1330Standard library
1331
1332- Keyword arguments are now accepted for most pattern and match object
1333 methods in SRE, the standard regular expression engine.
1334
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001335- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001336 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001337
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001338- Several bugs in the Unicode handling and error handling in _tkinter
1339 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001340
1341- Fix memory management errors in Merge() and Tkapp_Call() routines.
1342
1343- Several changes were made to cStringIO to make it compatible with
1344 the file-like object interface and with StringIO. If operations are
1345 performed on a closed object, an exception is raised. The truncate
1346 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001347 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001348
1349- There were many changes made to the linuxaudiodev module and its
1350 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001351 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001352
1353 Note that this module is named poorly, because it should work
1354 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001355 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001356
1357 The module now raises exceptions when errors occur instead of
1358 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1359 audio) and defines a getptr() method that calls the
1360 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1361
1362- The library_version attribute, introduced in an earlier beta, was
1363 removed because it can not be supported with early versions of the C
1364 readline library, which provides no way to determine the version at
1365 compile-time.
1366
1367- The binascii module is now enabled on Win64.
1368
Tim Peters46446d62000-10-09 21:19:31 +00001369- tokenize.py no longer suffers "recursion depth" errors when parsing
1370 programs with very long string literals.
1371
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001372Internals
1373
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001374- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001375 which is called when the interpreter starts up to determine where
1376 the standard library is installed. These vulnerabilities affect all
1377 previous versions of Python and can be exploited by setting very
1378 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1379 setuid Python script, although use of the wrapper in
1380 Misc/setuid-prog.c will eliminate the vulnerability.
1381
1382- Fixed garbage collection bugs in instance creation that were
1383 triggered when errors occurred during initialization. The solution,
1384 applied in cPickle and in PyInstance_New(), is to call
1385 PyObject_GC_Init() after the initialization of the object's
1386 container attributes is complete.
1387
1388- pyexpat adds definitions of PyModule_AddStringConstant and
1389 PyModule_AddObject if the Python version is less than 2.0, which
1390 provides compatibility with PyXML on Python 1.5.2.
1391
1392- If the platform has a bogus definition for LONG_BIT (the number of
1393 bits in a long), an error will be reported at compile time.
1394
1395- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1396 collection crashes and possibly other, unreported crashes.
1397
1398- Fixed a memory leak in _PyUnicode_Fini().
1399
1400Build issues
1401
1402- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001403 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001404 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001405
1406- The mmap.PAGESIZE constant is now initialized using sysconf when
1407 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1408
1409- The md5 file should now compile on all platforms.
1410
1411- The select module now compiles on platforms that do not define
1412 POLLRDNORM and related constants.
1413
1414- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001415 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001416
Jeremy Hylton10921202000-10-09 18:34:12 +00001417- BeOS: A number of changes were made to the build and installation
1418 process. ar-fake now operates on a directory of object files.
1419 dl_export.h is gone, and its macros now appear on the mwcc command
1420 line during build on PPC BeOS.
1421
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001422- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001423 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001424
1425- Cygwin: Support for shared libraries, Tkinter, and sockets.
1426
1427- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1428
1429Tools and other miscellany
1430
1431- Removed debugging prints from main used with freeze.
1432
Tim Peters46446d62000-10-09 21:19:31 +00001433- IDLE auto-indent no longer crashes when it encounters Unicode
1434 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001435
1436What's new in 2.0 beta 2 (since beta 1)?
1437========================================
1438
1439Core language, builtins, and interpreter
1440
Tim Peters482c0212000-09-26 06:33:09 +00001441- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001442 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001443
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001444- Add -h and -V command line options to print the usage message and
1445 Python version number and exit immediately.
1446
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001447- eval() and exec accept Unicode objects as code parameters.
1448
1449- getattr() and setattr() now also accept Unicode objects for the
1450 attribute name, which are converted to strings using the default
1451 encoding before lookup.
1452
1453- Multiplication on string and Unicode now does proper bounds
1454 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1455 string is too long."
1456
1457- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001458 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001459
Jeremy Hylton1b618592000-09-26 05:32:36 +00001460
1461Standard library and extensions
1462
Guido van Rossum5b08f132001-04-16 02:05:23 +00001463- socket module: the OpenSSL code now adds support for RAND_status()
1464 and EGD (Entropy Gathering Device).
1465
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001466- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001467 argument checking; it still takes no arguments.
1468
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001469- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001470
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001471- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001472
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001473- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001474
1475- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001476 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001477
1478- copy: Copy Unicode objects atomically.
1479
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001480- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001481
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001482- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001483
Fred Drake67233bc2000-09-26 16:40:27 +00001484- dbm: Add get() and setdefault() methods to dbm object. Add constant
1485 `library' to module that names the library used. Added doc strings
1486 and method names to error messages. Uses configure to determine
1487 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
1488 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001489
1490- distutils: Update to version 0.9.3.
1491
1492- dl: Add several dl.RTLD_ constants.
1493
1494- fpectl: Now supported on FreeBSD.
1495
1496- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
1497 found by the collector will be saved in gc.garbage. This is useful
1498 for debugging a program that creates reference cycles.
1499
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001500- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00001501 of HTTP class. Do not close socket on zero-length response. Do not
1502 crash when server sends invalid content-length header.
1503
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001504- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001505
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001506- marshal: When reading a short, sign-extend on platforms where shorts
1507 are bigger than 16 bits. When reading a long, repair the unportable
1508 sign extension that was being done for 64-bit machines. (It assumed
1509 that signed right shift sign-extends.)
1510
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001511- operator: Add contains(), invert(), __invert__() as aliases for
1512 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001513
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001514- os: Add support for popen2() and popen3() on all platforms where
1515 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001516
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001517- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00001518 clicking on a file in Explorer (or passing the file name to the
1519 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001520
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001521- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00001522 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001523
1524- pickle: Now raises ValueError when an invalid pickle that contains
1525 a non-string repr where a string repr was expected. This behavior
1526 matches cPickle.
1527
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001528- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001529
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001530- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001531
1532- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001533 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001534 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001535
1536- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001537 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001538
1539- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00001540 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00001541 few cycles during startup since the first call to
1542 setdefaultencoding() will initialize the codec registry and the
1543 encodings package.
1544
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001545- socket: Support for size hint in readlines() method of object returned
1546 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001547
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001548- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001549 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001550 is followed by whitespace.
1551
Tim Petersa3a3a032000-11-30 05:22:44 +00001552- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001553
1554- struct: Check ranges for bytes and shorts.
1555
1556- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001557 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001558
1559- Tkinter: Image objects are now guaranteed to have unique ids. Set
1560 event.delta to zero if Tk version doesn't support mousewheel.
1561 Removed some debugging prints.
1562
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001563- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001564
Fred Drake67233bc2000-09-26 16:40:27 +00001565- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001566 which works around a bug in Norton AntiVirus 2000 that leads directly
1567 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001568
1569- xml: New version detection code allows PyXML to override standard
1570 XML package if PyXML version is greater than 0.6.1.
1571
Fred Drake64bb3802000-09-26 16:21:35 +00001572- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
1573 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
1574 tree only for nodes which are sufficiently interesting to a specific
1575 application. Does not provide the HTML-specific extensions. Still
1576 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001577
Fred Drake64bb3802000-09-26 16:21:35 +00001578- xml.sax: SAX 2 support for Python, including all the handler
1579 interfaces needed to process XML 1.0 compliant XML. Some
1580 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001581
Fred Drake64bb3802000-09-26 16:21:35 +00001582- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
1583 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001584
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001585
Jeremy Hylton1b618592000-09-26 05:32:36 +00001586C API
1587
1588- Add three new convenience functions for module initialization --
1589 PyModule_AddObject(), PyModule_AddIntConstant(), and
1590 PyModule_AddStringConstant().
1591
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001592- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00001593 removed and add #error to Python.h if NULL isn't defined after
1594 #include of stdio.h.
1595
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001596- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00001597 backwards compatibility (at the source level) with old extensions.
1598
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001599- A wrapper API was added for signal() and sigaction(). Instead of
1600 either function, always use PyOS_getsig() to get a signal handler
1601 and PyOS_setsig() to set one. A new convenience typedef
1602 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001603
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001604- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00001605 internal data buffer and size of a string object -- or the default
1606 encoded version of a Unicode object.
1607
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001608- PyString_Size() and PyString_AsString() accept Unicode objects.
1609
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001610- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00001611 exists). INT_MAX and LONG_MAX will always be defined, even if
1612 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001613
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001614- PyFloat_FromString takes a second argument, pend, that was
1615 effectively useless. It is now officially useless but preserved for
1616 backwards compatibility. If the pend argument is not NULL, *pend is
1617 set to NULL.
1618
1619- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
1620 for the attribute name. See note on getattr() above.
1621
1622- A few bug fixes to argument processing for Unicode.
1623 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
1624 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
1625 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00001626 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001627
1628- Py_BuildValue accepts B format (for bgen-generated code).
1629
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001630
Jeremy Hylton1b618592000-09-26 05:32:36 +00001631Internals
1632
1633- On Unix, fix code for finding Python installation directory so that
1634 it works when argv[0] is a relative path.
1635
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00001636- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001637 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00001638 rather than by generating a copy of the object.
1639
Tim Peters482c0212000-09-26 06:33:09 +00001640- Several of the internal Unicode tables are much smaller now, and
1641 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001642
Jeremy Hylton97693b02000-09-26 17:42:51 +00001643- In the garbage collector: Fixed bug in collection of tuples. Fixed
1644 bug that caused some instances to be removed from the container set
1645 while they were still live. Fixed parsing in gc.set_debug() for
1646 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001647
1648- Fixed refcount problem in instance deallocation that only occurred
1649 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
1650
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001651- On Windows, getpythonregpath is now protected against null data in
1652 registry key.
1653
1654- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00001655 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001656
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001657
Jeremy Hylton1b618592000-09-26 05:32:36 +00001658Build and platform-specific issues
1659
1660- Better support of GNU Pth via --with-pth configure option.
1661
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001662- Python/C API now properly exposed to dynamically-loaded extension
1663 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001664
1665- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
1666 Don't define MS_SYNC to be zero when it is undefined. Added missing
1667 prototypes in posixmodule.c.
1668
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001669- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001670 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001671
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001672- Fix largefile support on older NetBSD systems and OpenBSD by adding
1673 define for TELL64.
1674
1675
1676Tools and other miscellany
1677
1678- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
1679
1680- freeze: The modulefinder now works with 2.0 opcodes.
1681
Tim Petersa3a3a032000-11-30 05:22:44 +00001682- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001683 Move hackery of sys.argv until after the Tk instance has been
1684 created, which allows the application-specific Tkinter
1685 initialization to be executed if present; also pass an explicit
1686 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00001687
Jeremy Hylton1b618592000-09-26 05:32:36 +00001688
1689What's new in 2.0 beta 1?
1690=========================
1691
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001692Source Incompatibilities
1693------------------------
1694
1695None. Note that 1.6 introduced several incompatibilities with 1.5.2,
1696such as single-argument append(), connect() and bind(), and changes to
1697str(long) and repr(float).
1698
1699
1700Binary Incompatibilities
1701------------------------
1702
1703- Third party extensions built for Python 1.5.x or 1.6 cannot be used
1704with Python 2.0; these extensions will have to be rebuilt for Python
17052.0.
1706
1707- On Windows, attempting to import a third party extension built for
1708Python 1.5.x or 1.6 results in an immediate crash; there's not much we
1709can do about this. Check your PYTHONPATH environment variable!
1710
1711- Python bytecode files (*.pyc and *.pyo) are not compatible between
1712releases.
1713
1714
1715Overview of Changes Since 1.6
1716-----------------------------
1717
1718There are many new modules (including brand new XML support through
1719the xml package, and i18n support through the gettext module); a list
1720of all new modules is included below. Lots of bugs have been fixed.
1721
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001722The process for making major new changes to the language has changed
1723since Python 1.6. Enhancements must now be documented by a Python
1724Enhancement Proposal (PEP) before they can be accepted.
1725
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001726There are several important syntax enhancements, described in more
1727detail below:
1728
1729 - Augmented assignment, e.g. x += 1
1730
1731 - List comprehensions, e.g. [x**2 for x in range(10)]
1732
1733 - Extended import statement, e.g. import Module as Name
1734
1735 - Extended print statement, e.g. print >> file, "Hello"
1736
1737Other important changes:
1738
1739 - Optional collection of cyclical garbage
1740
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001741Python Enhancement Proposal (PEP)
1742---------------------------------
1743
1744PEP stands for Python Enhancement Proposal. A PEP is a design
1745document providing information to the Python community, or describing
1746a new feature for Python. The PEP should provide a concise technical
1747specification of the feature and a rationale for the feature.
1748
1749We intend PEPs to be the primary mechanisms for proposing new
1750features, for collecting community input on an issue, and for
1751documenting the design decisions that have gone into Python. The PEP
1752author is responsible for building consensus within the community and
1753documenting dissenting opinions.
1754
1755The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001756
1757Augmented Assignment
1758--------------------
1759
1760This must have been the most-requested feature of the past years!
1761Eleven new assignment operators were added:
1762
Guido van Rossume905e952000-09-05 12:42:46 +00001763 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001764
1765For example,
1766
1767 A += B
1768
1769is similar to
1770
1771 A = A + B
1772
1773except that A is evaluated only once (relevant when A is something
1774like dict[index].attr).
1775
1776However, if A is a mutable object, A may be modified in place. Thus,
1777if A is a number or a string, A += B has the same effect as A = A+B
1778(except A is only evaluated once); but if a is a list, A += B has the
1779same effect as A.extend(B)!
1780
1781Classes and built-in object types can override the new operators in
1782order to implement the in-place behavior; the not-in-place behavior is
1783used automatically as a fallback when an object doesn't implement the
1784in-place behavior. For classes, the method name is derived from the
1785method name for the corresponding not-in-place operator by inserting
1786an 'i' in front of the name, e.g. __iadd__ implements in-place
1787__add__.
1788
1789Augmented assignment was implemented by Thomas Wouters.
1790
1791
1792List Comprehensions
1793-------------------
1794
1795This is a flexible new notation for lists whose elements are computed
1796from another list (or lists). The simplest form is:
1797
1798 [<expression> for <variable> in <sequence>]
1799
Guido van Rossum56db0952000-09-06 23:34:25 +00001800For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001801This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001802
1803You can also add a condition:
1804
1805 [<expression> for <variable> in <sequence> if <condition>]
1806
1807For example, [w for w in words if w == w.lower()] would yield the list
1808of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001809than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001810
1811You can also have nested for loops and more than one 'if' clause. For
1812example, here's a function that flattens a sequence of sequences::
1813
1814 def flatten(seq):
1815 return [x for subseq in seq for x in subseq]
1816
1817 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
1818
1819This prints
1820
1821 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
1822
1823List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001824Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001825
1826
1827Extended Import Statement
1828-------------------------
1829
1830Many people have asked for a way to import a module under a different
1831name. This can be accomplished like this:
1832
1833 import foo
1834 bar = foo
1835 del foo
1836
1837but this common idiom gets old quickly. A simple extension of the
1838import statement now allows this to be written as follows:
1839
1840 import foo as bar
1841
1842There's also a variant for 'from ... import':
1843
1844 from foo import bar as spam
1845
1846This also works with packages; e.g. you can write this:
1847
1848 import test.regrtest as regrtest
1849
1850Note that 'as' is not a new keyword -- it is recognized only in this
1851context (this is only possible because the syntax for the import
1852statement doesn't involve expressions).
1853
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001854Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001855
1856
1857Extended Print Statement
1858------------------------
1859
1860Easily the most controversial new feature, this extension to the print
1861statement adds an option to make the output go to a different file
1862than the default sys.stdout.
1863
1864For example, to write an error message to sys.stderr, you can now
1865write:
1866
1867 print >> sys.stderr, "Error: bad dog!"
1868
1869As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00001870evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001871
1872 print >> None, "Hello world"
1873
1874is equivalent to
1875
1876 print "Hello world"
1877
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001878Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001879
1880
1881Optional Collection of Cyclical Garbage
1882---------------------------------------
1883
1884Python is now equipped with a garbage collector that can hunt down
1885cyclical references between Python objects. It's no replacement for
1886reference counting; in fact, it depends on the reference counts being
1887correct, and decides that a set of objects belong to a cycle if all
1888their reference counts can be accounted for from their references to
1889each other. This devious scheme was first proposed by Eric Tiedemann,
1890and brought to implementation by Neil Schemenauer.
1891
1892There's a module "gc" that lets you control some parameters of the
1893garbage collection. There's also an option to the configure script
1894that lets you enable or disable the garbage collection. In 2.0b1,
1895it's on by default, so that we (hopefully) can collect decent user
1896experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00001897performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001898off by default in the final 2.0 release.
1899
1900
1901Smaller Changes
1902---------------
1903
1904A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
1905map(None, seq1, seq2, ...) when the sequences have the same length;
1906i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
1907the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001908zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001909
1910sys.version_info is a tuple (major, minor, micro, level, serial).
1911
1912Dictionaries have an odd new method, setdefault(key, default).
1913dict.setdefault(key, default) returns dict[key] if it exists; if not,
1914it sets dict[key] to default and returns that value. Thus:
1915
1916 dict.setdefault(key, []).append(item)
1917
1918does the same work as this common idiom:
1919
1920 if not dict.has_key(key):
1921 dict[key] = []
1922 dict[key].append(item)
1923
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001924There are two new variants of SyntaxError that are raised for
1925indentation-related errors: IndentationError and TabError.
1926
1927Changed \x to consume exactly two hex digits; see PEP 223. Added \U
1928escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001929
1930The limits on the size of expressions and file in Python source code
1931have been raised from 2**16 to 2**32. Previous versions of Python
1932were limited because the maximum argument size the Python VM accepted
1933was 2**16. This limited the size of object constructor expressions,
1934e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
1935limit was raised thanks to a patch by Charles Waldman that effectively
1936fixes the problem. It is now much more likely that you will be
1937limited by available memory than by an arbitrary limit in Python.
1938
1939The interpreter's maximum recursion depth can be modified by Python
1940programs using sys.getrecursionlimit and sys.setrecursionlimit. This
1941limit is the maximum number of recursive calls that can be made by
1942Python code. The limit exists to prevent infinite recursion from
1943overflowing the C stack and causing a core dump. The default value is
19441000. The maximum safe value for a particular platform can be found
1945by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001946
1947New Modules and Packages
1948------------------------
1949
1950atexit - for registering functions to be called when Python exits.
1951
1952imputil - Greg Stein's alternative API for writing custom import
1953hooks.
1954
1955pyexpat - an interface to the Expat XML parser, contributed by Paul
1956Prescod.
1957
1958xml - a new package with XML support code organized (so far) in three
1959subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
1960would fill a volume. There's a special feature whereby a
1961user-installed package named _xmlplus overrides the standard
1962xmlpackage; this is intended to give the XML SIG a hook to distribute
1963backwards-compatible updates to the standard xml package.
1964
1965webbrowser - a platform-independent API to launch a web browser.
1966
1967
Guido van Rossume905e952000-09-05 12:42:46 +00001968Changed Modules
1969---------------
1970
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001971array -- new methods for array objects: count, extend, index, pop, and
1972remove
1973
1974binascii -- new functions b2a_hex and a2b_hex that convert between
1975binary data and its hex representation
1976
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001977calendar -- Many new functions that support features including control
1978over which day of the week is the first day, returning strings instead
1979of printing them. Also new symbolic constants for days of week,
1980e.g. MONDAY, ..., SUNDAY.
1981
1982cgi -- FieldStorage objects have a getvalue method that works like a
1983dictionary's get method and returns the value attribute of the object.
1984
1985ConfigParser -- The parser object has new methods has_option,
1986remove_section, remove_option, set, and write. They allow the module
1987to be used for writing config files as well as reading them.
1988
1989ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00001990optionally support the RFC 959 REST command.
1991
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001992gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00001993
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001994httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
1995the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00001996
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001997locale -- implement getdefaultlocale for Win32 and Macintosh
1998
1999marshal -- no longer dumps core when marshaling deeply nested or
2000recursive data structures
2001
2002os -- new functions isatty, seteuid, setegid, setreuid, setregid
2003
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002004os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2005support under Unix.
2006
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002007os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002008
2009os.path -- fix semantics of os.path.commonprefix
2010
2011smtplib -- support for sending very long messages
2012
2013socket -- new function getfqdn()
2014
2015readline -- new functions to read, write and truncate history files.
2016The readline section of the library reference manual contains an
2017example.
2018
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002019select -- add interface to poll system call
2020
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002021shutil -- new copyfileobj function
2022
2023SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2024HTTP server.
2025
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002026Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002027
2028urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002029e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002030
2031whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002032
2033
2034Obsolete Modules
2035----------------
2036
2037None. However note that 1.6 made a whole slew of modules obsolete:
2038stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2039poly, zmod, strop, util, whatsound.
2040
2041
2042Changed, New, Obsolete Tools
2043----------------------------
2044
Tim Peters8b092332000-09-05 20:15:25 +00002045None.
Guido van Rossume905e952000-09-05 12:42:46 +00002046
2047
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002048C-level Changes
2049---------------
2050
2051Several cleanup jobs were carried out throughout the source code.
2052
2053All C code was converted to ANSI C; we got rid of all uses of the
2054Py_PROTO() macro, which makes the header files a lot more readable.
2055
2056Most of the portability hacks were moved to a new header file,
2057pyport.h; several other new header files were added and some old
2058header files were removed, in an attempt to create a more rational set
2059of header files. (Few of these ever need to be included explicitly;
2060they are all included by Python.h.)
2061
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002062Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002063and Win64, especially for the new Intel Itanium processor. Mick also
2064added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002065
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002066The C APIs to return an object's size have been update to consistently
2067use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2068previous versions, the abstract interfaces used PyXXX_Length and the
2069concrete interfaces used PyXXX_Size. The old names,
2070e.g. PyObject_Length, are still available for backwards compatibility
2071at the API level, but are deprecated.
2072
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002073The PyOS_CheckStack function has been implemented on Windows by
2074Fredrik Lundh. It prevents Python from failing with a stack overflow
2075on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002076
2077The GC changes resulted in creation of two new slots on object,
2078tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002079the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002080
2081The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002082C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002083
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002084PyErr_Format has been updated to automatically calculate the size of
2085the buffer needed to hold the formatted result string. This change
2086prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002087
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002088New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002089
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002090PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2091that are the same as their non-Ex counterparts except they take an
2092extra flag argument that tells them to close the file when done.
2093
2094XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002095
Tim Peters8b092332000-09-05 20:15:25 +00002096
2097Windows Changes
2098---------------
2099
2100New popen2/popen3/peopen4 in os module (see Changed Modules above).
2101
2102os.popen is much more usable on Windows 95 and 98. See Microsoft
2103Knowledge Base article Q150956. The Win9x workaround described there
2104is implemented by the new w9xpopen.exe helper in the root of your
2105Python installation. Note that Python uses this internally; it is not
2106a standalone program.
2107
2108Administrator privileges are no longer required to install Python
2109on Windows NT or Windows 2000. If you have administrator privileges,
2110Python's registry info will be written under HKEY_LOCAL_MACHINE.
2111Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002112under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002113uses of Python, but will prevent some advanced uses from working
2114(for example, running a Python script as an NT service, or possibly
2115from CGI).
2116
2117[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2118installer; instead, it installs the needed Tcl/Tk files directly in the
2119Python directory. If you already have a Tcl/Tk installation, this
2120wastes some disk space (about 4 Megs) but avoids problems with
2121conflicting Tcl/Tk installations, and makes it much easier for Python
2122to ensure that Tcl/Tk can find all its files.
2123
2124[This was new in 1.6] The Windows installer now installs by default in
2125\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2126
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002127
2128Updates to the changes between 1.5.2 and 1.6
2129--------------------------------------------
2130
2131The 1.6 NEWS file can't be changed after the release is done, so here
2132is some late-breaking news:
2133
2134New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2135and changes to getlocale() and setlocale().
2136
2137The new module is now enabled per default.
2138
2139It is not true that the encodings codecs cannot be used for normal
2140strings: the string.encode() (which is also present on 8-bit strings
2141!) allows using them for 8-bit strings too, e.g. to convert files from
2142cp1252 (Windows) to latin-1 or vice-versa.
2143
2144Japanese codecs are available from Tamito KAJIYAMA:
2145http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2146
2147
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002148======================================================================