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Tim Petersf553f892001-05-01 20:45:31 +00001What's New in Python 2.2a0?
2===========================
3
4Core
5
Tim Peters61dff2b2001-05-08 15:43:37 +00006- Float (and complex) literals in source code were evaluated to full
7 precision only when running from a .py file; the same code loaded from a
8 .pyc (or .pyo) file could suffer numeric differences starting at about the
9 12th significant decimal digit. For example, on a machine with IEEE-754
10 floating arithmetic,
11
12 x = 9007199254740992.0
13 print long(x)
14
15 printed 9007199254740992 if run directly from .py, but 9007199254740000
16 if from a compiled (.pyc or .pyo) file. This was due to marshal using
17 str(float) instead of repr(float) when building code objects. marshal
18 now uses repr(float) instead, which should reproduce floats to full
19 machine precision (assuming the platform C float<->string I/O conversion
20 functions are of good quality).
21
22 This may cause floating-point results to change in some cases, and
23 usually for the better, but may also cause numerically unstable
24 algorithms to break.
25
Guido van Rossum10315822001-05-01 20:54:30 +000026- Dictionary objects now support the "in" operator: "x in dict" means
27 the same as dict.has_key(x).
28
29- Iterators were added; this is a generalized way of providing values
30 to a for loop. See PEP 234. There's a new built-in function iter()
31 to return an iterator. There's a new protocol to get the next value
32 from an iterator using the next() method (in Python) or the
33 tp_iternext slot (in C). There's a new protocol to get iterators
34 using the __iter__() method (in Python) or the tp_iter slot (in C).
35 Iterating (i.e. a for loop) over a dictionary generates its keys.
36 Iterating over a file generates its lines.
37
Tim Petersf553f892001-05-01 20:45:31 +000038- The following functions were generalized to work nicely with iterator
39 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +000040 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +000041 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
42 max(), min()
Tim Petersde9725f2001-05-05 10:06:17 +000043 .join() method of strings
Tim Peters75f8e352001-05-05 11:33:43 +000044 'x in y' and 'x not in y' (PySequence_Contains() in C API)
45 operator.countOf() (PySequence_Count() in C API)
Tim Peters75f8e352001-05-05 11:33:43 +000046
Tim Peterse63415e2001-05-08 04:38:29 +000047- Comparing dictionary objects via == and != is faster, and now works even
48 if the keys and values don't support comparisons other than ==.
49
Tim Petersf553f892001-05-01 20:45:31 +000050
Guido van Rossumffe13be2001-04-16 18:46:45 +000051What's New in Python 2.1 (final)?
52=================================
53
54We only changed a few things since the last release candidate, all in
55Python library code:
56
57- A bug in the locale module was fixed that affected locales which
58 define no grouping for numeric formatting.
59
60- A few bugs in the weakref module's implementations of weak
61 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
62 and the test suite was updated to check for these bugs.
63
64- An old bug in the os.path.walk() function (introduced in Python
65 2.0!) was fixed: a non-existent file would cause an exception
66 instead of being ignored.
67
68- Fixed a few bugs in the new symtable module found by Neil Norwitz's
69 PyChecker.
70
71
Guido van Rossum5b08f132001-04-16 02:05:23 +000072What's New in Python 2.1c2?
73===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +000074
Guido van Rossum5b08f132001-04-16 02:05:23 +000075A flurry of small changes, and one showstopper fixed in the nick of
76time made it necessary to release another release candidate. The list
77here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +000078
Guido van Rossum5b08f132001-04-16 02:05:23 +000079Core
Guido van Rossum4fb60362001-04-13 00:46:14 +000080
Guido van Rossum5b08f132001-04-16 02:05:23 +000081- Tim discovered a nasty bug in the dictionary code, caused by
82 PyDict_Next() calling dict_resize(), and the GC code's use of
83 PyDict_Next() violating an assumption in dict_items(). This was
84 fixed with considerable amounts of band-aid, but the net effect is a
85 saner and more robust implementation.
86
87- Made a bunch of symbols static that were accidentally global.
88
89Build and Ports
90
91- The setup.py script didn't check for a new enough version of zlib
92 (1.1.3 is needed). Now it does.
93
94- Changed "make clean" target to also remove shared libraries.
95
96- Added a more general warning about the SGI Irix optimizer to README.
97
98Library
99
100- Fix a bug in urllib.basejoin("http://host", "../file.html") which
101 omitted the slash between host and file.html.
102
103- The mailbox module's _Mailbox class contained a completely broken
104 and undocumented seek() method. Ripped it out.
105
106- Fixed a bunch of typos in various library modules (urllib2, smtpd,
107 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
108
109- Fixed a few last-minute bugs in unittest.
110
111Extensions
112
113- Reverted the patch to the OpenSSL code in socketmodule.c to support
114 RAND_status() and the EGD, and the subsequent patch that tried to
115 fix it for pre-0.9.5 versions; the problem with the patch is that on
116 some systems it issues a warning whenever socket is imported, and
117 that's unacceptable.
118
119Tests
120
121- Fixed the pickle tests to work with "import test.test_pickle".
122
123- Tweaked test_locale.py to actually run the test Windows.
124
125- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
126 not "wb" (which is not a valid mode at all).
127
128- Fix pstats browser crashes. Import readline if it exists to make
129 the user interface nicer.
130
131- Add "import thread" to the top of test modules that import the
132 threading module (test_asynchat and test_threadedtempfile). This
133 prevents test failures caused by a broken threading module resulting
134 from a previously caught failed import.
135
136- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
137 needed on some platforms (e.g. Solaris 8) when the tests are run
138 twice in succession.
139
140- Skip rather than fail test_sunaudiodev if no audio device is found.
141
142
143What's New in Python 2.1c1?
144===========================
145
146This list was significantly updated when 2.1c2 was released; the 2.1c1
147release didn't mention most changes that were actually part of 2.1c1:
148
149Legal
150
151- Copyright was assigned to the Python Software Foundation (PSF) and a
152 PSF license (very similar to the CNRI license) was added.
153
154- The CNRI copyright notice was updated to include 2001.
155
156Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000157
Guido van Rossumc9932722001-04-12 02:31:27 +0000158- After a public outcry, assignment to __debug__ is no longer illegal;
159 instead, a warning is issued. It will become illegal in 2.2.
160
Guido van Rossum5b08f132001-04-16 02:05:23 +0000161- Fixed a core dump with "%#x" % 0, and changed the semantics so that
162 "%#x" now always prepends "0x", even if the value is zero.
163
164- Fixed some nits in the bytecode compiler.
165
166- Fixed core dumps when calling certain kinds of non-functions.
167
168- Fixed various core dumps caused by reference count bugs.
169
170Build and Ports
171
172- Use INSTALL_SCRIPT to install script files.
173
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000174- New port: SCO Unixware 7, by Billy G. Allie.
175
Guido van Rossum5b08f132001-04-16 02:05:23 +0000176- Updated RISCOS port.
177
178- Updated BeOS port and notes.
179
180- Various other porting problems resolved.
181
182Library
183
184- The TERMIOS and SOCKET modules are now truly obsolete and
185 unnecessary. Their symbols are incorporated in the termios and
186 socket modules.
187
188- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
189 better tests for pickling.
190
191- threading: make Condition.wait() robust against KeyboardInterrupt.
192
193- zipfile: add support to zipfile to support opening an archive
194 represented by an open file rather than a file name. Fix bug where
195 the archive was not properly closed. Fixed a bug in this bugfix
196 where flush() was called for a read-only file.
197
198- imputil: added an uninstall() method to the ImportManager.
199
200- Canvas: fixed bugs in lower() and tkraise() methods.
201
202- SocketServer: API change (added overridable close_request() method)
203 so that the TCP server can explicitly close the request.
204
205- pstats: Eric Raymond added a simple interactive statistics browser,
206 invoked when the module is run as a script.
207
208- locale: fixed a problem in format().
209
210- webbrowser: made it work when the BROWSER environment variable has a
211 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
212 KDE 2. Fixed some other nits.
213
214- unittest: changes to allow using a different exception than
215 AssertionError, and added a few more function aliases. Some other
216 small changes.
217
218- urllib, urllib2: fixed redirect problems and a coupleof other nits.
219
220- asynchat: fixed a critical bug in asynchat that slipped through the
221 2.1b2 release. Fixed another rare bug.
222
223- Fix some unqualified except: clauses (always a bad code example).
224
225XML
226
227- pyexpat: new API get_version_string().
228
229- Fixed some minidom bugs.
230
231Extensions
232
233- Fixed a core dump in _weakref. Removed the weakref.mapping()
234 function (it adds nothing to the API).
235
236- Rationalized the use of header files in the readline module, to make
237 it compile (albeit with some warnings) with the very recent readline
238 4.2, without breaking for earlier versions.
239
240- Hopefully fixed a buffering problem in linuxaudiodev.
241
242- Attempted a fix to make the OpenSSL support in the socket module
243 work again with pre-0.9.5 versions of OpenSSL.
244
245Tests
246
247- Added a test case for asynchat and asyncore.
248
249- Removed coupling between tests where one test failing could break
250 another.
251
252Tools
253
254- Ping added an interactive help browser to pydoc, fixed some nits
255 in the rest of the pydoc code, and added some features to his
256 inspect module.
257
258- An updated python-mode.el version 4.1 which integrates Ken
259 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
260 much nicer in XEmacs and Emacs. When stepping through your program
261 with pdb, in either the shell window or the *Python* window, the
262 source file and line will be tracked by an arrow. Very cool!
263
264- IDLE: syntax warnings in interactive mode are changed into errors.
265
266- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +0000267 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +0000268
269- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000270
Barry Warsaw11e89c72001-04-11 20:37:57 +0000271
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000272What's New in Python 2.1 beta 2?
273================================
274
Guido van Rossum053ae352001-03-22 14:17:21 +0000275(Unlisted are many fixed bugs, more documentation, etc.)
276
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000277Core language, builtins, and interpreter
278
Guido van Rossum053ae352001-03-22 14:17:21 +0000279- The nested scopes work (enabled by "from __future__ import
280 nested_scopes") is completed; in particular, the future now extends
281 into code executed through exec, eval() and execfile(), and into the
282 interactive interpreter.
283
284- When calling a base class method (e.g. BaseClass.__init__(self)),
285 this is now allowed even if self is not strictly spoken a class
286 instance (e.g. when using metaclasses or the Don Beaudry hook).
287
288- Slice objects are now comparable but not hashable; this prevents
289 dict[:] from being accepted but meaningless.
290
291- Complex division is now calculated using less braindead algorithms.
292 This doesn't change semantics except it's more likely to give useful
293 results in extreme cases. Complex repr() now uses full precision
294 like float repr().
295
296- sgmllib.py now calls handle_decl() for simple <!...> declarations.
297
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000298- It is illegal to assign to the name __debug__, which is set when the
299 interpreter starts. It is effectively a compile-time constant.
300
301- A warning will be issued if a global statement for a variable
302 follows a use or assignment of that variable.
303
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000304Standard library
305
Guido van Rossum053ae352001-03-22 14:17:21 +0000306- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
307 inspired by JUnit), is now part of the standard library. You now
308 have a choice of two testing frameworks: unittest requires you to
309 write testcases as separate code, doctest gathers them from
310 docstrings. Both approaches have their advantages and
311 disadvantages.
312
313- A new module Tix was added, which wraps the Tix extension library
314 for Tk. With that module, it is not necessary to statically link
315 Tix with _tkinter, since Tix will be loaded with Tcl's "package
316 require" command. See Demo/tix/.
317
318- tzparse.py is now obsolete.
319
320- In gzip.py, the seek() and tell() methods are removed -- they were
321 non-functional anyway, and it's better if callers can test for their
322 existence with hasattr().
323
324Python/C API
325
326- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
327 that's already in the dictionary during a PyDict_Next() iteration.
328 This used to fail occasionally when a dictionary resize operation
329 could be triggered that would rehash all the keys. All other
330 modifications to the dictionary are still off-limits during a
331 PyDict_Next() iteration!
332
333- New extended APIs related to passing compiler variables around.
334
335- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
336 implement isinstance() and issubclass().
337
338- Py_BuildValue() now has a "D" conversion to create a Python complex
339 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000340
Fred Drake4e262a92001-03-22 18:26:47 +0000341- Extensions types which support weak references must now set the
342 field allocated for the weak reference machinery to NULL themselves;
343 this is done to avoid the cost of checking each object for having a
344 weakly referencable type in PyObject_INIT(), since most types are
345 not weakly referencable.
346
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000347- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
348 free variables and cell variables to and from the frame's f_locals.
349
350- Variants of several functions defined in pythonrun.h have been added
351 to support the nested_scopes future statement. The variants all end
352 in Flags and take an extra argument, a PyCompilerFlags *; examples:
353 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
354 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +0000355 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000356
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000357Distutils
358
359- the sdist command now writes a PKG-INFO file, as described in PEP 241,
360 into the release tree.
361
Tim Peters0e57abf2001-05-02 07:39:38 +0000362- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000363 (an uninstaller, more customization of the installer's display)
364
365- from Jack Jansen: added Mac-specific code to generate a dialog for
366 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +0000367 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000368 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +0000369
370- added 'platforms' and 'keywords' to the set of metadata that can be
371 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000372
373- applied patches from Jason Tishler to make the compiler class work with
374 Cygwin.
375
376
Tim Peters2fe289a2001-03-01 22:19:38 +0000377What's New in Python 2.1 beta 1?
378================================
Tim Petersd66595f2001-02-04 03:09:53 +0000379
380Core language, builtins, and interpreter
381
Guido van Rossum9d0fbde2001-03-02 14:00:32 +0000382- Following an outcry from the community about the amount of code
383 broken by the nested scopes feature introduced in 2.1a2, we decided
384 to make this feature optional, and to wait until Python 2.2 (or at
385 least 6 months) to make it standard. The option can be enabled on a
386 per-module basis by adding "from __future__ import nested_scopes" at
387 the beginning of a module (before any other statements, but after
388 comments and an optional docstring). See PEP 236 (Back to the
389 __future__) for a description of the __future__ statement. PEP 227
390 (Statically Nested Scopes) has been updated to reflect this change,
391 and to clarify the semantics in a number of endcases.
392
393- The nested scopes code, when enabled, has been hardened, and most
394 bugs and memory leaks in it have been fixed.
395
396- Compile-time warnings are now generated for a number of conditions
397 that will break or change in meaning when nested scopes are enabled:
398
399 - Using "from...import *" or "exec" without in-clause in a function
400 scope that also defines a lambda or nested function with one or
401 more free (non-local) variables. The presence of the import* or
402 bare exec makes it impossible for the compiler to determine the
403 exact set of local variables in the outer scope, which makes it
404 impossible to determine the bindings for free variables in the
405 inner scope. To avoid the warning about import *, change it into
406 an import of explicitly name object, or move the import* statement
407 to the global scope; to avoid the warning about bare exec, use
408 exec...in... (a good idea anyway -- there's a possibility that
409 bare exec will be deprecated in the future).
410
411 - Use of a global variable in a nested scope with the same name as a
412 local variable in a surrounding scope. This will change in
413 meaning with nested scopes: the name in the inner scope will
414 reference the variable in the outer scope rather than the global
415 of the same name. To avoid the warning, either rename the outer
416 variable, or use a global statement in the inner function.
417
Neil Schemenauera35c6882001-02-27 04:45:05 +0000418- An optional object allocator has been included. This allocator is
419 optimized for Python objects and should be faster and use less memory
420 than the standard system allocator. It is not enabled by default
421 because of possible thread safety problems. The allocator is only
422 protected by the Python interpreter lock and it is possible that some
423 extension modules require a thread safe allocator. The object
424 allocator can be enabled by providing the "--with-pymalloc" option to
425 configure.
426
Tim Petersd66595f2001-02-04 03:09:53 +0000427Standard library
428
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000429- pyexpat now detects the expat version if expat.h defines it. A
430 number of additional handlers are provided, which are only available
431 since expat 1.95. In addition, the methods SetParamEntityParsing and
432 GetInputContext of Parser objects are available with 1.95.x
433 only. Parser objects now provide the ordered_attributes and
434 specified_attributes attributes. A new module expat.model was added,
435 which offers a number of additional constants if 1.95.x is used.
436
437- xml.dom offers the new functions registerDOMImplementation and
438 getDOMImplementation.
439
440- xml.dom.minidom offers a toprettyxml method. A number of DOM
441 conformance issues have been resolved. In particular, Element now
442 has an hasAttributes method, and the handling of namespaces was
443 improved.
444
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000445- Ka-Ping Yee contributed two new modules: inspect.py, a module for
446 getting information about live Python code, and pydoc.py, a module
447 for interactively converting docstrings to HTML or text.
448 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +0000449 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +0000450 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
451 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000452
Tim Peters1eff7962001-03-01 02:31:33 +0000453- New library module difflib.py, primarily packaging the SequenceMatcher
454 class at the heart of the popular ndiff.py file-comparison tool.
455
456- doctest.py (a framework for verifying Python code examples in docstrings)
457 is now part of the std library.
458
Tim Petersd66595f2001-02-04 03:09:53 +0000459Windows changes
460
Guido van Rossume3955a82001-03-02 14:05:59 +0000461- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
462 small GUI that lets you browse the module docstrings using your
463 default web browser.
464
Tim Peters1eff7962001-03-01 02:31:33 +0000465- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
466 Platforms) is implemented. See
467
468 http://python.sourceforge.net/peps/pep-0235.html
469
470 for full details, especially the "Current Lower-Left Semantics" section.
471 The new Windows import rules are simpler than before:
472
473 A. If the PYTHONCASEOK environment variable exists, same as
474 before: silently accept the first case-insensitive match of any
475 kind; raise ImportError if none found.
476
477 B. Else search sys.path for the first case-sensitive match; raise
478 ImportError if none found.
479
480 The same rules have been implented on other platforms with case-
481 insensitive but case-preserving filesystems too (including Cygwin, and
482 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +0000483
Tim Peters25a9ce32001-02-19 07:06:36 +0000484- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
485 what it's supposed to do (and does do under NT and 2000) via direct
486 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +0000487 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +0000488 all Win9x systems before.
489
Tim Peters1eff7962001-03-01 02:31:33 +0000490- Build: Subproject _test (effectively) renamed to _testcapi.
491
Tim Peters2fe289a2001-03-01 22:19:38 +0000492New platforms
493
494- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
495 Thanks to Steven Majewski!
496
497- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
498 Tishler!
499
Guido van Rossum9089b272001-03-02 06:49:50 +0000500- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
501 Schwertberger! See RISCOS/README for more information -- it seems
502 that because of the bizarre filename conventions on RISCOS, no port
503 to that platform is easy. Note that the new variable os.endsep is
504 silently supported in order to make life easier on this platform,
505 but we don't advertise it because it's not worth for most folks to
506 care about RISCOS portability.
507
Tim Peters25a9ce32001-02-19 07:06:36 +0000508
Tim Petersd7b5e882001-01-25 03:36:26 +0000509What's New in Python 2.1 alpha 2?
510=================================
Tim Peters40ead762001-01-27 05:35:26 +0000511
Tim Petersd7b5e882001-01-25 03:36:26 +0000512Core language, builtins, and interpreter
513
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000514- Scopes nest. If a name is used in a function or class, but is not
515 local, the definition in the nearest enclosing function scope will
516 be used. One consequence of this change is that lambda statements
517 could reference variables in the namespaces where the lambda is
518 defined. In some unusual cases, this change will break code.
519
520 In all previous version of Python, names were resolved in exactly
521 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000522 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000523 function A is defined within a function B, the names bound in B are
524 not visible in A. The new rules make names bound in B visible in A,
525 unless A contains a name binding that hides the binding in B.
526
527 Section 4.1 of the reference manual describes the new scoping rules
528 in detail. The test script in Lib/test/test_scope.py demonstrates
529 some of the effects of the change.
530
531 The new rules will cause existing code to break if it defines nested
532 functions where an outer function has local variables with the same
533 name as globals or builtins used by the inner function. Example:
534
535 def munge(str):
536 def helper(x):
537 return str(x)
538 if type(str) != type(''):
539 str = helper(str)
540 return str.strip()
541
542 Under the old rules, the name str in helper() is bound to the
543 builtin function str(). Under the new rules, it will be bound to
544 the argument named str and an error will occur when helper() is
545 called.
546
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000547- The compiler will report a SyntaxError if "from ... import *" occurs
548 in a function or class scope. The language reference has documented
549 that this case is illegal, but the compiler never checked for it.
550 The recent introduction of nested scope makes the meaning of this
551 form of name binding ambiguous. In a future release, the compiler
552 may allow this form when there is no possibility of ambiguity.
553
Tim Peters40ead762001-01-27 05:35:26 +0000554- repr(string) is easier to read, now using hex escapes instead of octal,
555 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
556
557 >>> "\texample \r\n" + chr(0) + chr(255)
558 '\texample \r\n\x00\xff' # in 2.1
559 '\011example \015\012\000\377' # in 2.0
560
Moshe Zadka6af0ce02001-01-29 06:41:00 +0000561- Functions are now compared and hashed by identity, not by value, since
562 the func_code attribute is writable.
563
Fred Drakefb9d7122001-02-01 20:00:40 +0000564- Weak references (PEP 205) have been added. This involves a few
565 changes in the core, an extension module (_weakref), and a Python
566 module (weakref). The weakref module is the public interface. It
567 includes support for "explicit" weak references, proxy objects, and
568 mappings with weakly held values.
569
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000570- A 'continue' statement can now appear in a try block within the body
571 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +0000572 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000573
Tim Petersd7b5e882001-01-25 03:36:26 +0000574Standard library
575
Barry Warsaw30dbd142001-01-31 22:14:01 +0000576- mailbox.py now has a new class, PortableUnixMailbox which is
577 identical to UnixMailbox but uses a more portable scheme for
578 determining From_ separators. Also, the constructors for all the
579 classes in this module have a new optional `factory' argument, which
580 is a callable used when new message classes must be instantiated by
581 the next() method.
582
Tim Petersd7b5e882001-01-25 03:36:26 +0000583- random.py is now self-contained, and offers all the functionality of
584 the now-deprecated whrandom.py. See the docs for details. random.py
585 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +0000586 and restoring the internal state of the generator; and jumpahead(n),
587 for quickly forcing the internal state to be the same as if n calls to
588 random() had been made. The latter is particularly useful for multi-
589 threaded programs, creating one instance of the random.Random() class for
590 each thread, then using .jumpahead() to force each instance to use a
591 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +0000592
Tim Peters0de88fc2001-02-01 04:59:18 +0000593- random.py's seed() function is new. For bit-for-bit compatibility with
594 prior releases, use the whseed function instead. The new seed function
595 addresses two problems: (1) The old function couldn't produce more than
596 about 2**24 distinct internal states; the new one about 2**45 (the best
597 that can be done in the Wichmann-Hill generator). (2) The old function
598 sometimes produced identical internal states when passed distinct
599 integers, and there was no simple way to predict when that would happen;
600 the new one guarantees to produce distinct internal states for all
601 arguments in [0, 27814431486576L).
602
Jeremy Hylton4c4fda02001-02-02 03:29:24 +0000603- The socket module now supports raw packets on Linux. The socket
604 family is AF_PACKET.
605
Tim Peters9ea17ac2001-02-02 05:57:15 +0000606- test_capi.py is a start at running tests of the Python C API. The tests
607 are implemented by the new Modules/_testmodule.c.
608
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000609- A new extension module, _symtable, provides provisional access to the
610 internal symbol table used by the Python compiler. A higher-level
611 interface will be added on top of _symtable in a future release.
612
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +0000613- Removed the obsolete soundex module.
614
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000615- xml.dom.minidom now uses the standard DOM exceptions. Node supports
616 the isSameNode method; NamedNodeMap the get method.
617
618- xml.sax.expatreader supports the lexical handler property; it
619 generates comment, startCDATA, and endCDATA events.
620
Tim Petersee826f82001-01-31 19:39:44 +0000621Windows changes
622
623- Build procedure: the zlib project is built in a different way that
624 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +0000625 the zlib binary used. See PCbuild\readme.txt for details. Your old
626 zlib-related directories can be deleted; you'll need to download fresh
627 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +0000628
Tim Peters9ea17ac2001-02-02 05:57:15 +0000629- Build: New subproject _test for the benefit of test_capi.py (see above).
630
Tim Petersb16c56f2001-02-02 21:24:51 +0000631- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
632 interface to some Python compiler internals).
633
634- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +0000635 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +0000636
Tim Petersa3a3a032000-11-30 05:22:44 +0000637What's New in Python 2.1 alpha 1?
638=================================
639
640Core language, builtins, and interpreter
641
Marc-André Lemburgebb195b2001-01-20 10:34:52 +0000642- There is a new Unicode companion to the PyObject_Str() API
643 called PyObject_Unicode(). It behaves in the same way as the
644 former, but assures that the returned value is an Unicode object
645 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +0000646
Guido van Rossumf98eda02001-01-17 15:54:45 +0000647- The comparison operators support "rich comparison overloading" (PEP
648 207). C extension types can provide a rich comparison function in
649 the new tp_richcompare slot in the type object. The cmp() function
650 and the C function PyObject_Compare() first try the new rich
651 comparison operators before trying the old 3-way comparison. There
652 is also a new C API PyObject_RichCompare() (which also falls back on
653 the old 3-way comparison, but does not constrain the outcome of the
654 rich comparison to a Boolean result).
655
656 The rich comparison function takes two objects (at least one of
657 which is guaranteed to have the type that provided the function) and
658 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
659 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
660 object, which may be NotImplemented (in which case the tp_compare
661 slot function is used as a fallback, if defined).
662
663 Classes can overload individual comparison operators by defining one
664 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +0000665 __ge__. There are no explicit "reflected argument" versions of
666 these; instead, __lt__ and __gt__ are each other's reflection,
667 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
668 reflection (similar at the C level). No other implications are
669 made; in particular, Python does not assume that == is the Boolean
670 inverse of !=, or that < is the Boolean inverse of >=. This makes
671 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +0000672
673 Classes or types that want to implement (in)equality tests but not
674 the ordering operators (i.e. unordered types) should implement ==
675 and !=, and raise an error for the ordering operators.
676
Guido van Rossuma88479f2001-01-18 14:28:08 +0000677 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +0000678 Boolean; e.g. a matrix type might want to return a matrix of bits
679 for A < B, giving elementwise comparisons. Such types should ensure
680 that any interpretation of their value in a Boolean context raises
681 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
682 at the C level) to always raise an exception.
683
Guido van Rossuma88479f2001-01-18 14:28:08 +0000684- Complex numbers use rich comparisons to define == and != but raise
685 an exception for <, <=, > and >=. Unfortunately, this also means
686 that cmp() of two complex numbers raises an exception when the two
687 numbers differ. Since it is not mathematically meaningful to compare
688 complex numbers except for equality, I hope that this doesn't break
689 too much code.
690
Tim Peters3389f192001-02-18 08:48:49 +0000691- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +0000692 not defined by the language, other than that it's arbitrary but
693 consistent (see the Reference Manual). An implementation detail changed
694 in 2.1a1 such that None now compares less than any other object. Code
695 relying on this new behavior (like code that relied on the previous
696 behavior) does so at its own risk.
697
Barry Warsaw573b5412001-01-15 20:43:18 +0000698- Functions and methods now support getting and setting arbitrarily
699 named attributes (PEP 232). Functions have a new __dict__
700 (a.k.a. func_dict) which hold the function attributes. Methods get
701 and set attributes on their underlying im_func. It is a TypeError
702 to set an attribute on a bound method.
703
Guido van Rossum051e3352001-01-15 19:11:10 +0000704- The xrange() object implementation has been improved so that
705 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
706 limitation that in this case len(xrange(sys.maxint)) can't be
707 calculated, but the common idiom "for i in xrange(sys.maxint)" will
708 work fine as long as the index i doesn't actually reach 2**31.
709 (Python uses regular ints for sequence and string indices; fixing
710 that is much more work.)
711
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000712- Two changes to from...import:
713
Guido van Rossumba381232001-02-03 15:06:40 +0000714 1) "from M import X" now works even if (after loading module M)
715 sys.modules['M'] is not a real module; it's basically a getattr()
716 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000717
718 2) "from M import *" now looks for M.__all__ to decide which names to
719 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
720 filters out names starting with '_' as before. Whether or not
721 __all__ exists, there's no restriction on the type of M.
722
Guido van Rossumf61f1662001-01-10 20:13:55 +0000723- File objects have a new method, xreadlines(). This is the fastest
724 way to iterate over all lines in a file:
725
726 for line in file.xreadlines():
727 ...do something to line...
728
729 See the xreadlines module (mentioned below) for how to do this for
730 other file-like objects.
731
732- Even if you don't use file.xreadlines(), you may expect a speedup on
733 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +0000734 quite a bit in platform-specific ways: on systems (like Linux) that
735 support flockfile(), getc_unlocked(), and funlockfile(), those are
736 used by default. On systems (like Windows) without getc_unlocked(),
737 a complicated (but still thread-safe) method using fgets() is used by
738 default.
739
Tim Petersd52269b2001-01-25 06:23:18 +0000740 You can force use of the fgets() method by #define'ing
741 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +0000742 getc_unlocked()).
743
Tim Petersd52269b2001-01-25 06:23:18 +0000744 You can force fgets() not to be used by #define'ing
745 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +0000746 test_bufio.py fails -- and let us know if it does!).
747
748- In addition, the fileinput module, while still slower than the other
749 methods on most platforms, has been sped up too, by using
750 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +0000751
752- Support for run-time warnings has been added, including a new
753 command line option (-W) to specify the disposition of warnings.
754 See the description of the warnings module below.
755
756- Extensive changes have been made to the coercion code. This mostly
757 affects extension modules (which can now implement mixed-type
758 numerical operators without having to use coercion), but
759 occasionally, in boundary cases the coercion semantics have changed
760 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +0000761 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +0000762 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +0000763 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +0000764
Guido van Rossumf98eda02001-01-17 15:54:45 +0000765- In connection with the coercion changes, a new built-in singleton
766 object, NotImplemented is defined. This can be returned for
767 operations that wish to indicate they are not implemented for a
768 particular combination of arguments. From C, this is
769 Py_NotImplemented.
770
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +0000771- The interpreter accepts now bytecode files on the command line even
772 if they do not have a .pyc or .pyo extension. On Linux, after executing
773
Martin v. Löwise214baa2001-02-04 22:37:56 +0000774import imp,sys,string
775magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
776reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
777open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +0000778
779 any byte code file can be used as an executable (i.e. as an argument
780 to execve(2)).
781
Tim Peters9940b802000-12-01 07:59:35 +0000782- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +0000783 character. In 1.6 and earlier, they never produced a sign,
784 and raised an error if the value of the long was too large
785 to fit in a Python int. In 2.0, they produced a sign if and
786 only if too large to fit in an int. This was inconsistent
787 across platforms (because the size of an int varies across
788 platforms), and inconsistent with hex() and oct(). Example:
789
790 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +0000791 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +0000792 'ffffffbe' # in 2.0 and before, on 32-bit machines
793 >>> hex(-0x42L)
794 '-0x42L' # in all versions of Python
795
Tim Peters9940b802000-12-01 07:59:35 +0000796 The behavior of %d formats for negative Python longs remains
797 the same as in 2.0 (although in 1.6 and before, they raised
798 an error if the long didn't fit in a Python int).
799
800 %u formats don't make sense for Python longs, but are allowed
801 and treated the same as %d in 2.1. In 2.0, a negative long
802 formatted via %u produced a sign if and only if too large to
803 fit in an int. In 1.6 and earlier, a negative long formatted
804 via %u raised an error if it was too big to fit in an int.
805
Guido van Rossum3661d392000-12-12 22:10:31 +0000806- Dictionary objects have an odd new method, popitem(). This removes
807 an arbitrary item from the dictionary and returns it (in the form of
808 a (key, value) pair). This can be useful for algorithms that use a
809 dictionary as a bag of "to do" items and repeatedly need to pick one
810 item. Such algorithms normally end up running in quadratic time;
811 using popitem() they can usually be made to run in linear time.
812
Tim Peters36cdad12000-12-29 02:06:45 +0000813Standard library
814
Thomas Woutersfe385252001-01-19 23:16:56 +0000815- In the time module, the time argument to the functions strftime,
816 localtime, gmtime, asctime and ctime is now optional, defaulting to
817 the current time (in the local timezone).
818
Guido van Rossumda91f222001-01-15 16:36:08 +0000819- The ftplib module now defaults to passive mode, which is deemed a
820 more useful default given that clients are often inside firewalls
821 these days. Note that this could break if ftplib is used to connect
822 to a *server* that is inside a firewall, from outside; this is
823 expected to be a very rare situation. To fix that, you can call
824 ftp.set_pasv(0).
825
Martin v. Löwis10a27872001-01-13 09:54:41 +0000826- The module site now treats .pth files not only for path configuration,
827 but also supports extensions to the initialization code: Lines starting
828 with import are executed.
829
Guido van Rossumf61f1662001-01-10 20:13:55 +0000830- There's a new module, warnings, which implements a mechanism for
831 issuing and filtering warnings. There are some new built-in
832 exceptions that serve as warning categories, and a new command line
833 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
834 turns warnings into errors). warnings.warn(message[, category])
835 issues a warning message; this can also be called from C as
836 PyErr_Warn(category, message).
837
838- A new module xreadlines was added. This exports a single factory
839 function, xreadlines(). The intention is that this code is the
840 absolutely fastest way to iterate over all lines in an open
841 file(-like) object:
842
843 import xreadlines
844 for line in xreadlines.xreadlines(file):
845 ...do something to line...
846
847 This is equivalent to the previous the speed record holder using
848 file.readlines(sizehint). Note that if file is a real file object
849 (as opposed to a file-like object), this is equivalent:
850
851 for line in file.xreadlines():
852 ...do something to line...
853
Tim Peters36cdad12000-12-29 02:06:45 +0000854- The bisect module has new functions bisect_left, insort_left,
855 bisect_right and insort_right. The old names bisect and insort
856 are now aliases for bisect_right and insort_right. XXX_right
857 and XXX_left methods differ in what happens when the new element
858 compares equal to one or more elements already in the list: the
859 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +0000860 right. Code that doesn't care where equal elements end up should
861 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +0000862
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +0000863- The new curses.panel module wraps the panel library that forms part
864 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
865
Guido van Rossumf61f1662001-01-10 20:13:55 +0000866- The SocketServer module now sets the allow_reuse_address flag by
867 default in the TCPServer class.
868
869- A new function, sys._getframe(), returns the stack frame pointer of
870 the caller. This is intended only as a building block for
871 higher-level mechanisms such as string interpolation.
872
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000873- The pyexpat module supports a number of new handlers, which are
874 available only in expat 1.2. If invocation of a callback fails, it
875 will report an additional frame in the traceback. Parser objects
876 participate now in garbage collection. If expat reports an unknown
877 encoding, pyexpat will try to use a Python codec; that works only
878 for single-byte charsets. The parser type objects is exposed as
879 XMLParserObject.
880
881- xml.dom now offers standard definitions for symbolic node type and
882 exception code constants, and a hierarchy of DOM exceptions. minidom
883 was adjusted to use them.
884
885- The conformance of xml.dom.minidom to the DOM specification was
886 improved. It detects a number of additional error cases; the
887 previous/next relationship works even when the tree is modified;
888 Node supports the normalize() method; NamedNodeMap, DocumentType and
889 DOMImplementation classes were added; Element supports the
890 hasAttribute and hasAttributeNS methods; and Text supports the splitText
891 method.
892
Guido van Rossumf61f1662001-01-10 20:13:55 +0000893Build issues
894
Guido van Rossum1e33bdc2001-01-23 03:17:00 +0000895- For Unix (and Unix-compatible) builds, configuration and building of
896 extension modules is now greatly automated. Rather than having to
897 edit the Modules/Setup file to indicate which modules should be
898 built and where their include files and libraries are, a
899 distutils-based setup.py script now takes care of building most
900 extension modules. All extension modules built this way are built
901 as shared libraries. Only a few modules that must be linked
902 statically are still listed in the Setup file; you won't need to
903 edit their configuration.
904
905- Python should now build out of the box on Cygwin. If it doesn't,
906 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +0000907
908- Python now always uses its own (renamed) implementation of getopt()
909 -- there's too much variation among C library getopt()
910 implementations.
911
912- C++ compilers are better supported; the CXX macro is always set to a
913 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +0000914
Tim Petersd92dfe02000-12-12 01:18:41 +0000915Windows changes
916
917- select module: By default under Windows, a select() call
918 can specify no more than 64 sockets. Python now boosts
919 this Microsoft default to 512. If you need even more than
920 that, see the MS docs (you'll need to #define FD_SETSIZE
921 and recompile Python from source).
922
Guido van Rossumf61f1662001-01-10 20:13:55 +0000923- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
924 subdirectory is no more!
925
Tim Petersa3a3a032000-11-30 05:22:44 +0000926
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000927What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +0000928=========================
Guido van Rossum61000331997-08-15 04:39:58 +0000929
Guido van Rossum8ed602b2000-09-01 22:34:33 +0000930Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000931changes are in the file HISTORY. If you are making the jump directly
932from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
933HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +0000934
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000935Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
936the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
937http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +0000938
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000939--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +0000940
941======================================================================
942
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000943What's new in 2.0 (since release candidate 1)?
944==============================================
945
946Standard library
947
948- The copy_reg module was modified to clarify its intended use: to
949 register pickle support for extension types, not for classes.
950 pickle() will raise a TypeError if it is passed a class.
951
952- Fixed a bug in gettext's "normalize and expand" code that prevented
953 it from finding an existing .mo file.
954
955- Restored support for HTTP/0.9 servers in httplib.
956
Tim Peters989b7b92000-10-16 20:24:53 +0000957- The math module was changed to stop raising OverflowError in case of
958 underflow, and return 0 instead in underflow cases. Whether Python
959 used to raise OverflowError in case of underflow was platform-
960 dependent (it did when the platform math library set errno to ERANGE
961 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000962
963- Fixed a bug in StringIO that occurred when the file position was not
964 at the end of the file and write() was called with enough data to
965 extend past the end of the file.
966
967- Fixed a bug that caused Tkinter error messages to get lost on
968 Windows. The bug was fixed by replacing direct use of
969 interp->result with Tcl_GetStringResult(interp).
970
971- Fixed bug in urllib2 that caused it to fail when it received an HTTP
972 redirect response.
973
974- Several changes were made to distutils: Some debugging code was
975 removed from util. Fixed the installer used when an external zip
976 program (like WinZip) is not found; the source code for this
977 installer is in Misc/distutils. check_lib() was modified to behave
978 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
979 test for whether installed modules are on sys.path was changed to
980 use both normcase() and normpath().
981
Jeremy Hyltond867a2c2000-10-16 20:41:38 +0000982- Several minor bugs were fixed in the xml package (the minidom,
983 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000984
985- The regression test driver (regrtest.py) behavior when invoked with
986 -l changed: It now reports a count of objects that are recognized as
987 garbage but not freed by the garbage collector.
988
Tim Peters989b7b92000-10-16 20:24:53 +0000989- The regression test for the math module was changed to test
990 exceptional behavior when the test is run in verbose mode. Python
991 cannot yet guarantee consistent exception behavior across platforms,
992 so the exception part of test_math is run only in verbose mode, and
993 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000994
995Internals
996
997- PyOS_CheckStack() has been disabled on Win64, where it caused
998 test_sre to fail.
999
1000Build issues
1001
1002- Changed compiler flags, so that gcc is always invoked with -Wall and
1003 -Wstrict-prototypes. Users compiling Python with GCC should see
1004 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001005 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001006 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001007
Tim Petersa3a3a032000-11-30 05:22:44 +00001008- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001009
1010Tools and other miscellany
1011
1012- The compiler in Tools/compiler was updated to support the new
1013 language features introduced in 2.0: extended print statement, list
1014 comprehensions, and augmented assignments. The new compiler should
1015 also be backwards compatible with Python 1.5.2; the compiler will
1016 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001017 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001018
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001019What's new in 2.0 release candidate 1 (since beta 2)?
1020=====================================================
1021
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001022What is release candidate 1?
1023
1024We believe that release candidate 1 will fix all known bugs that we
1025intend to fix for the 2.0 final release. This release should be a bit
1026more stable than the previous betas. We would like to see even more
1027widespread testing before the final release, so we are producing this
1028release candidate. The final release will be exactly the same unless
1029any show-stopping (or brown bag) bugs are found by testers of the
1030release candidate.
1031
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001032All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001033to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001034
1035Core language, builtins, and interpreter
1036
1037- A bug that caused crashes when __coerce__ was used with augmented
1038 assignment, e.g. +=, was fixed.
1039
1040- Raise ZeroDivisionError when raising zero to a negative number,
1041 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1042 power operator and the result of math.pow(0.0, -2.0) will vary by
1043 platform. On Linux, it raises a ValueError.
1044
1045- A bug in Unicode string interpolation was fixed that occasionally
1046 caused errors with formats including "%%". For example, the
1047 following expression "%% %s" % u"abc" no longer raises a TypeError.
1048
1049- Compilation of deeply nested expressions raises MemoryError instead
1050 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1051
1052- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1053 rendering them useless. They are now written in binary mode again.
1054
1055Standard library
1056
1057- Keyword arguments are now accepted for most pattern and match object
1058 methods in SRE, the standard regular expression engine.
1059
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001060- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001061 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001062
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001063- Several bugs in the Unicode handling and error handling in _tkinter
1064 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001065
1066- Fix memory management errors in Merge() and Tkapp_Call() routines.
1067
1068- Several changes were made to cStringIO to make it compatible with
1069 the file-like object interface and with StringIO. If operations are
1070 performed on a closed object, an exception is raised. The truncate
1071 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001072 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001073
1074- There were many changes made to the linuxaudiodev module and its
1075 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001076 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001077
1078 Note that this module is named poorly, because it should work
1079 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001080 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001081
1082 The module now raises exceptions when errors occur instead of
1083 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1084 audio) and defines a getptr() method that calls the
1085 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1086
1087- The library_version attribute, introduced in an earlier beta, was
1088 removed because it can not be supported with early versions of the C
1089 readline library, which provides no way to determine the version at
1090 compile-time.
1091
1092- The binascii module is now enabled on Win64.
1093
Tim Peters46446d62000-10-09 21:19:31 +00001094- tokenize.py no longer suffers "recursion depth" errors when parsing
1095 programs with very long string literals.
1096
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001097Internals
1098
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001099- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001100 which is called when the interpreter starts up to determine where
1101 the standard library is installed. These vulnerabilities affect all
1102 previous versions of Python and can be exploited by setting very
1103 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1104 setuid Python script, although use of the wrapper in
1105 Misc/setuid-prog.c will eliminate the vulnerability.
1106
1107- Fixed garbage collection bugs in instance creation that were
1108 triggered when errors occurred during initialization. The solution,
1109 applied in cPickle and in PyInstance_New(), is to call
1110 PyObject_GC_Init() after the initialization of the object's
1111 container attributes is complete.
1112
1113- pyexpat adds definitions of PyModule_AddStringConstant and
1114 PyModule_AddObject if the Python version is less than 2.0, which
1115 provides compatibility with PyXML on Python 1.5.2.
1116
1117- If the platform has a bogus definition for LONG_BIT (the number of
1118 bits in a long), an error will be reported at compile time.
1119
1120- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1121 collection crashes and possibly other, unreported crashes.
1122
1123- Fixed a memory leak in _PyUnicode_Fini().
1124
1125Build issues
1126
1127- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001128 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001129 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001130
1131- The mmap.PAGESIZE constant is now initialized using sysconf when
1132 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1133
1134- The md5 file should now compile on all platforms.
1135
1136- The select module now compiles on platforms that do not define
1137 POLLRDNORM and related constants.
1138
1139- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001140 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001141
Jeremy Hylton10921202000-10-09 18:34:12 +00001142- BeOS: A number of changes were made to the build and installation
1143 process. ar-fake now operates on a directory of object files.
1144 dl_export.h is gone, and its macros now appear on the mwcc command
1145 line during build on PPC BeOS.
1146
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001147- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001148 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001149
1150- Cygwin: Support for shared libraries, Tkinter, and sockets.
1151
1152- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1153
1154Tools and other miscellany
1155
1156- Removed debugging prints from main used with freeze.
1157
Tim Peters46446d62000-10-09 21:19:31 +00001158- IDLE auto-indent no longer crashes when it encounters Unicode
1159 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001160
1161What's new in 2.0 beta 2 (since beta 1)?
1162========================================
1163
1164Core language, builtins, and interpreter
1165
Tim Peters482c0212000-09-26 06:33:09 +00001166- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001167 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001168
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001169- Add -h and -V command line options to print the usage message and
1170 Python version number and exit immediately.
1171
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001172- eval() and exec accept Unicode objects as code parameters.
1173
1174- getattr() and setattr() now also accept Unicode objects for the
1175 attribute name, which are converted to strings using the default
1176 encoding before lookup.
1177
1178- Multiplication on string and Unicode now does proper bounds
1179 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1180 string is too long."
1181
1182- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001183 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001184
Jeremy Hylton1b618592000-09-26 05:32:36 +00001185
1186Standard library and extensions
1187
Guido van Rossum5b08f132001-04-16 02:05:23 +00001188- socket module: the OpenSSL code now adds support for RAND_status()
1189 and EGD (Entropy Gathering Device).
1190
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001191- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001192 argument checking; it still takes no arguments.
1193
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001194- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001195
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001196- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001197
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001198- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001199
1200- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001201 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001202
1203- copy: Copy Unicode objects atomically.
1204
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001205- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001206
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001207- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001208
Fred Drake67233bc2000-09-26 16:40:27 +00001209- dbm: Add get() and setdefault() methods to dbm object. Add constant
1210 `library' to module that names the library used. Added doc strings
1211 and method names to error messages. Uses configure to determine
1212 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
1213 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001214
1215- distutils: Update to version 0.9.3.
1216
1217- dl: Add several dl.RTLD_ constants.
1218
1219- fpectl: Now supported on FreeBSD.
1220
1221- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
1222 found by the collector will be saved in gc.garbage. This is useful
1223 for debugging a program that creates reference cycles.
1224
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001225- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00001226 of HTTP class. Do not close socket on zero-length response. Do not
1227 crash when server sends invalid content-length header.
1228
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001229- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001230
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001231- marshal: When reading a short, sign-extend on platforms where shorts
1232 are bigger than 16 bits. When reading a long, repair the unportable
1233 sign extension that was being done for 64-bit machines. (It assumed
1234 that signed right shift sign-extends.)
1235
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001236- operator: Add contains(), invert(), __invert__() as aliases for
1237 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001238
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001239- os: Add support for popen2() and popen3() on all platforms where
1240 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001241
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001242- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00001243 clicking on a file in Explorer (or passing the file name to the
1244 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001245
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001246- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00001247 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001248
1249- pickle: Now raises ValueError when an invalid pickle that contains
1250 a non-string repr where a string repr was expected. This behavior
1251 matches cPickle.
1252
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001253- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001254
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001255- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001256
1257- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001258 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001259 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001260
1261- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001262 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001263
1264- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00001265 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00001266 few cycles during startup since the first call to
1267 setdefaultencoding() will initialize the codec registry and the
1268 encodings package.
1269
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001270- socket: Support for size hint in readlines() method of object returned
1271 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001272
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001273- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001274 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001275 is followed by whitespace.
1276
Tim Petersa3a3a032000-11-30 05:22:44 +00001277- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001278
1279- struct: Check ranges for bytes and shorts.
1280
1281- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001282 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001283
1284- Tkinter: Image objects are now guaranteed to have unique ids. Set
1285 event.delta to zero if Tk version doesn't support mousewheel.
1286 Removed some debugging prints.
1287
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001288- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001289
Fred Drake67233bc2000-09-26 16:40:27 +00001290- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001291 which works around a bug in Norton AntiVirus 2000 that leads directly
1292 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001293
1294- xml: New version detection code allows PyXML to override standard
1295 XML package if PyXML version is greater than 0.6.1.
1296
Fred Drake64bb3802000-09-26 16:21:35 +00001297- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
1298 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
1299 tree only for nodes which are sufficiently interesting to a specific
1300 application. Does not provide the HTML-specific extensions. Still
1301 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001302
Fred Drake64bb3802000-09-26 16:21:35 +00001303- xml.sax: SAX 2 support for Python, including all the handler
1304 interfaces needed to process XML 1.0 compliant XML. Some
1305 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001306
Fred Drake64bb3802000-09-26 16:21:35 +00001307- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
1308 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001309
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001310
Jeremy Hylton1b618592000-09-26 05:32:36 +00001311C API
1312
1313- Add three new convenience functions for module initialization --
1314 PyModule_AddObject(), PyModule_AddIntConstant(), and
1315 PyModule_AddStringConstant().
1316
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001317- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00001318 removed and add #error to Python.h if NULL isn't defined after
1319 #include of stdio.h.
1320
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001321- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00001322 backwards compatibility (at the source level) with old extensions.
1323
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001324- A wrapper API was added for signal() and sigaction(). Instead of
1325 either function, always use PyOS_getsig() to get a signal handler
1326 and PyOS_setsig() to set one. A new convenience typedef
1327 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001328
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001329- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00001330 internal data buffer and size of a string object -- or the default
1331 encoded version of a Unicode object.
1332
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001333- PyString_Size() and PyString_AsString() accept Unicode objects.
1334
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001335- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00001336 exists). INT_MAX and LONG_MAX will always be defined, even if
1337 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001338
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001339- PyFloat_FromString takes a second argument, pend, that was
1340 effectively useless. It is now officially useless but preserved for
1341 backwards compatibility. If the pend argument is not NULL, *pend is
1342 set to NULL.
1343
1344- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
1345 for the attribute name. See note on getattr() above.
1346
1347- A few bug fixes to argument processing for Unicode.
1348 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
1349 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
1350 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00001351 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001352
1353- Py_BuildValue accepts B format (for bgen-generated code).
1354
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001355
Jeremy Hylton1b618592000-09-26 05:32:36 +00001356Internals
1357
1358- On Unix, fix code for finding Python installation directory so that
1359 it works when argv[0] is a relative path.
1360
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00001361- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001362 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00001363 rather than by generating a copy of the object.
1364
Tim Peters482c0212000-09-26 06:33:09 +00001365- Several of the internal Unicode tables are much smaller now, and
1366 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001367
Jeremy Hylton97693b02000-09-26 17:42:51 +00001368- In the garbage collector: Fixed bug in collection of tuples. Fixed
1369 bug that caused some instances to be removed from the container set
1370 while they were still live. Fixed parsing in gc.set_debug() for
1371 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001372
1373- Fixed refcount problem in instance deallocation that only occurred
1374 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
1375
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001376- On Windows, getpythonregpath is now protected against null data in
1377 registry key.
1378
1379- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00001380 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001381
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001382
Jeremy Hylton1b618592000-09-26 05:32:36 +00001383Build and platform-specific issues
1384
1385- Better support of GNU Pth via --with-pth configure option.
1386
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001387- Python/C API now properly exposed to dynamically-loaded extension
1388 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001389
1390- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
1391 Don't define MS_SYNC to be zero when it is undefined. Added missing
1392 prototypes in posixmodule.c.
1393
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001394- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001395 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001396
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001397- Fix largefile support on older NetBSD systems and OpenBSD by adding
1398 define for TELL64.
1399
1400
1401Tools and other miscellany
1402
1403- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
1404
1405- freeze: The modulefinder now works with 2.0 opcodes.
1406
Tim Petersa3a3a032000-11-30 05:22:44 +00001407- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001408 Move hackery of sys.argv until after the Tk instance has been
1409 created, which allows the application-specific Tkinter
1410 initialization to be executed if present; also pass an explicit
1411 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00001412
Jeremy Hylton1b618592000-09-26 05:32:36 +00001413
1414What's new in 2.0 beta 1?
1415=========================
1416
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001417Source Incompatibilities
1418------------------------
1419
1420None. Note that 1.6 introduced several incompatibilities with 1.5.2,
1421such as single-argument append(), connect() and bind(), and changes to
1422str(long) and repr(float).
1423
1424
1425Binary Incompatibilities
1426------------------------
1427
1428- Third party extensions built for Python 1.5.x or 1.6 cannot be used
1429with Python 2.0; these extensions will have to be rebuilt for Python
14302.0.
1431
1432- On Windows, attempting to import a third party extension built for
1433Python 1.5.x or 1.6 results in an immediate crash; there's not much we
1434can do about this. Check your PYTHONPATH environment variable!
1435
1436- Python bytecode files (*.pyc and *.pyo) are not compatible between
1437releases.
1438
1439
1440Overview of Changes Since 1.6
1441-----------------------------
1442
1443There are many new modules (including brand new XML support through
1444the xml package, and i18n support through the gettext module); a list
1445of all new modules is included below. Lots of bugs have been fixed.
1446
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001447The process for making major new changes to the language has changed
1448since Python 1.6. Enhancements must now be documented by a Python
1449Enhancement Proposal (PEP) before they can be accepted.
1450
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001451There are several important syntax enhancements, described in more
1452detail below:
1453
1454 - Augmented assignment, e.g. x += 1
1455
1456 - List comprehensions, e.g. [x**2 for x in range(10)]
1457
1458 - Extended import statement, e.g. import Module as Name
1459
1460 - Extended print statement, e.g. print >> file, "Hello"
1461
1462Other important changes:
1463
1464 - Optional collection of cyclical garbage
1465
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001466Python Enhancement Proposal (PEP)
1467---------------------------------
1468
1469PEP stands for Python Enhancement Proposal. A PEP is a design
1470document providing information to the Python community, or describing
1471a new feature for Python. The PEP should provide a concise technical
1472specification of the feature and a rationale for the feature.
1473
1474We intend PEPs to be the primary mechanisms for proposing new
1475features, for collecting community input on an issue, and for
1476documenting the design decisions that have gone into Python. The PEP
1477author is responsible for building consensus within the community and
1478documenting dissenting opinions.
1479
1480The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001481
1482Augmented Assignment
1483--------------------
1484
1485This must have been the most-requested feature of the past years!
1486Eleven new assignment operators were added:
1487
Guido van Rossume905e952000-09-05 12:42:46 +00001488 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001489
1490For example,
1491
1492 A += B
1493
1494is similar to
1495
1496 A = A + B
1497
1498except that A is evaluated only once (relevant when A is something
1499like dict[index].attr).
1500
1501However, if A is a mutable object, A may be modified in place. Thus,
1502if A is a number or a string, A += B has the same effect as A = A+B
1503(except A is only evaluated once); but if a is a list, A += B has the
1504same effect as A.extend(B)!
1505
1506Classes and built-in object types can override the new operators in
1507order to implement the in-place behavior; the not-in-place behavior is
1508used automatically as a fallback when an object doesn't implement the
1509in-place behavior. For classes, the method name is derived from the
1510method name for the corresponding not-in-place operator by inserting
1511an 'i' in front of the name, e.g. __iadd__ implements in-place
1512__add__.
1513
1514Augmented assignment was implemented by Thomas Wouters.
1515
1516
1517List Comprehensions
1518-------------------
1519
1520This is a flexible new notation for lists whose elements are computed
1521from another list (or lists). The simplest form is:
1522
1523 [<expression> for <variable> in <sequence>]
1524
Guido van Rossum56db0952000-09-06 23:34:25 +00001525For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001526This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001527
1528You can also add a condition:
1529
1530 [<expression> for <variable> in <sequence> if <condition>]
1531
1532For example, [w for w in words if w == w.lower()] would yield the list
1533of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001534than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001535
1536You can also have nested for loops and more than one 'if' clause. For
1537example, here's a function that flattens a sequence of sequences::
1538
1539 def flatten(seq):
1540 return [x for subseq in seq for x in subseq]
1541
1542 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
1543
1544This prints
1545
1546 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
1547
1548List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001549Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001550
1551
1552Extended Import Statement
1553-------------------------
1554
1555Many people have asked for a way to import a module under a different
1556name. This can be accomplished like this:
1557
1558 import foo
1559 bar = foo
1560 del foo
1561
1562but this common idiom gets old quickly. A simple extension of the
1563import statement now allows this to be written as follows:
1564
1565 import foo as bar
1566
1567There's also a variant for 'from ... import':
1568
1569 from foo import bar as spam
1570
1571This also works with packages; e.g. you can write this:
1572
1573 import test.regrtest as regrtest
1574
1575Note that 'as' is not a new keyword -- it is recognized only in this
1576context (this is only possible because the syntax for the import
1577statement doesn't involve expressions).
1578
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001579Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001580
1581
1582Extended Print Statement
1583------------------------
1584
1585Easily the most controversial new feature, this extension to the print
1586statement adds an option to make the output go to a different file
1587than the default sys.stdout.
1588
1589For example, to write an error message to sys.stderr, you can now
1590write:
1591
1592 print >> sys.stderr, "Error: bad dog!"
1593
1594As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00001595evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001596
1597 print >> None, "Hello world"
1598
1599is equivalent to
1600
1601 print "Hello world"
1602
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001603Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001604
1605
1606Optional Collection of Cyclical Garbage
1607---------------------------------------
1608
1609Python is now equipped with a garbage collector that can hunt down
1610cyclical references between Python objects. It's no replacement for
1611reference counting; in fact, it depends on the reference counts being
1612correct, and decides that a set of objects belong to a cycle if all
1613their reference counts can be accounted for from their references to
1614each other. This devious scheme was first proposed by Eric Tiedemann,
1615and brought to implementation by Neil Schemenauer.
1616
1617There's a module "gc" that lets you control some parameters of the
1618garbage collection. There's also an option to the configure script
1619that lets you enable or disable the garbage collection. In 2.0b1,
1620it's on by default, so that we (hopefully) can collect decent user
1621experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00001622performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001623off by default in the final 2.0 release.
1624
1625
1626Smaller Changes
1627---------------
1628
1629A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
1630map(None, seq1, seq2, ...) when the sequences have the same length;
1631i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
1632the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001633zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001634
1635sys.version_info is a tuple (major, minor, micro, level, serial).
1636
1637Dictionaries have an odd new method, setdefault(key, default).
1638dict.setdefault(key, default) returns dict[key] if it exists; if not,
1639it sets dict[key] to default and returns that value. Thus:
1640
1641 dict.setdefault(key, []).append(item)
1642
1643does the same work as this common idiom:
1644
1645 if not dict.has_key(key):
1646 dict[key] = []
1647 dict[key].append(item)
1648
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001649There are two new variants of SyntaxError that are raised for
1650indentation-related errors: IndentationError and TabError.
1651
1652Changed \x to consume exactly two hex digits; see PEP 223. Added \U
1653escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001654
1655The limits on the size of expressions and file in Python source code
1656have been raised from 2**16 to 2**32. Previous versions of Python
1657were limited because the maximum argument size the Python VM accepted
1658was 2**16. This limited the size of object constructor expressions,
1659e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
1660limit was raised thanks to a patch by Charles Waldman that effectively
1661fixes the problem. It is now much more likely that you will be
1662limited by available memory than by an arbitrary limit in Python.
1663
1664The interpreter's maximum recursion depth can be modified by Python
1665programs using sys.getrecursionlimit and sys.setrecursionlimit. This
1666limit is the maximum number of recursive calls that can be made by
1667Python code. The limit exists to prevent infinite recursion from
1668overflowing the C stack and causing a core dump. The default value is
16691000. The maximum safe value for a particular platform can be found
1670by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001671
1672New Modules and Packages
1673------------------------
1674
1675atexit - for registering functions to be called when Python exits.
1676
1677imputil - Greg Stein's alternative API for writing custom import
1678hooks.
1679
1680pyexpat - an interface to the Expat XML parser, contributed by Paul
1681Prescod.
1682
1683xml - a new package with XML support code organized (so far) in three
1684subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
1685would fill a volume. There's a special feature whereby a
1686user-installed package named _xmlplus overrides the standard
1687xmlpackage; this is intended to give the XML SIG a hook to distribute
1688backwards-compatible updates to the standard xml package.
1689
1690webbrowser - a platform-independent API to launch a web browser.
1691
1692
Guido van Rossume905e952000-09-05 12:42:46 +00001693Changed Modules
1694---------------
1695
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001696array -- new methods for array objects: count, extend, index, pop, and
1697remove
1698
1699binascii -- new functions b2a_hex and a2b_hex that convert between
1700binary data and its hex representation
1701
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001702calendar -- Many new functions that support features including control
1703over which day of the week is the first day, returning strings instead
1704of printing them. Also new symbolic constants for days of week,
1705e.g. MONDAY, ..., SUNDAY.
1706
1707cgi -- FieldStorage objects have a getvalue method that works like a
1708dictionary's get method and returns the value attribute of the object.
1709
1710ConfigParser -- The parser object has new methods has_option,
1711remove_section, remove_option, set, and write. They allow the module
1712to be used for writing config files as well as reading them.
1713
1714ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00001715optionally support the RFC 959 REST command.
1716
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001717gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00001718
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001719httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
1720the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00001721
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001722locale -- implement getdefaultlocale for Win32 and Macintosh
1723
1724marshal -- no longer dumps core when marshaling deeply nested or
1725recursive data structures
1726
1727os -- new functions isatty, seteuid, setegid, setreuid, setregid
1728
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001729os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
1730support under Unix.
1731
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001732os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001733
1734os.path -- fix semantics of os.path.commonprefix
1735
1736smtplib -- support for sending very long messages
1737
1738socket -- new function getfqdn()
1739
1740readline -- new functions to read, write and truncate history files.
1741The readline section of the library reference manual contains an
1742example.
1743
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001744select -- add interface to poll system call
1745
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001746shutil -- new copyfileobj function
1747
1748SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
1749HTTP server.
1750
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001751Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001752
1753urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00001754e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001755
1756whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00001757
1758
1759Obsolete Modules
1760----------------
1761
1762None. However note that 1.6 made a whole slew of modules obsolete:
1763stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
1764poly, zmod, strop, util, whatsound.
1765
1766
1767Changed, New, Obsolete Tools
1768----------------------------
1769
Tim Peters8b092332000-09-05 20:15:25 +00001770None.
Guido van Rossume905e952000-09-05 12:42:46 +00001771
1772
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001773C-level Changes
1774---------------
1775
1776Several cleanup jobs were carried out throughout the source code.
1777
1778All C code was converted to ANSI C; we got rid of all uses of the
1779Py_PROTO() macro, which makes the header files a lot more readable.
1780
1781Most of the portability hacks were moved to a new header file,
1782pyport.h; several other new header files were added and some old
1783header files were removed, in an attempt to create a more rational set
1784of header files. (Few of these ever need to be included explicitly;
1785they are all included by Python.h.)
1786
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001787Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001788and Win64, especially for the new Intel Itanium processor. Mick also
1789added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001790
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001791The C APIs to return an object's size have been update to consistently
1792use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
1793previous versions, the abstract interfaces used PyXXX_Length and the
1794concrete interfaces used PyXXX_Size. The old names,
1795e.g. PyObject_Length, are still available for backwards compatibility
1796at the API level, but are deprecated.
1797
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001798The PyOS_CheckStack function has been implemented on Windows by
1799Fredrik Lundh. It prevents Python from failing with a stack overflow
1800on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001801
1802The GC changes resulted in creation of two new slots on object,
1803tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00001804the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001805
1806The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00001807C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001808
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001809PyErr_Format has been updated to automatically calculate the size of
1810the buffer needed to hold the formatted result string. This change
1811prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001812
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001813New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00001814
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001815PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
1816that are the same as their non-Ex counterparts except they take an
1817extra flag argument that tells them to close the file when done.
1818
1819XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00001820
Tim Peters8b092332000-09-05 20:15:25 +00001821
1822Windows Changes
1823---------------
1824
1825New popen2/popen3/peopen4 in os module (see Changed Modules above).
1826
1827os.popen is much more usable on Windows 95 and 98. See Microsoft
1828Knowledge Base article Q150956. The Win9x workaround described there
1829is implemented by the new w9xpopen.exe helper in the root of your
1830Python installation. Note that Python uses this internally; it is not
1831a standalone program.
1832
1833Administrator privileges are no longer required to install Python
1834on Windows NT or Windows 2000. If you have administrator privileges,
1835Python's registry info will be written under HKEY_LOCAL_MACHINE.
1836Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00001837under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00001838uses of Python, but will prevent some advanced uses from working
1839(for example, running a Python script as an NT service, or possibly
1840from CGI).
1841
1842[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
1843installer; instead, it installs the needed Tcl/Tk files directly in the
1844Python directory. If you already have a Tcl/Tk installation, this
1845wastes some disk space (about 4 Megs) but avoids problems with
1846conflicting Tcl/Tk installations, and makes it much easier for Python
1847to ensure that Tcl/Tk can find all its files.
1848
1849[This was new in 1.6] The Windows installer now installs by default in
1850\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
1851
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001852
1853Updates to the changes between 1.5.2 and 1.6
1854--------------------------------------------
1855
1856The 1.6 NEWS file can't be changed after the release is done, so here
1857is some late-breaking news:
1858
1859New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
1860and changes to getlocale() and setlocale().
1861
1862The new module is now enabled per default.
1863
1864It is not true that the encodings codecs cannot be used for normal
1865strings: the string.encode() (which is also present on 8-bit strings
1866!) allows using them for 8-bit strings too, e.g. to convert files from
1867cp1252 (Windows) to latin-1 or vice-versa.
1868
1869Japanese codecs are available from Tamito KAJIYAMA:
1870http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
1871
1872
Guido van Rossumab9d6f01998-08-10 22:01:13 +00001873======================================================================