blob: 617146c9719b95fd79a6ed634a32fd5e64ecd1ff [file] [log] [blame]
Tim Petersf553f892001-05-01 20:45:31 +00001What's New in Python 2.2a0?
2===========================
3
4Core
5
Guido van Rossum10315822001-05-01 20:54:30 +00006- Dictionary objects now support the "in" operator: "x in dict" means
7 the same as dict.has_key(x).
8
9- Iterators were added; this is a generalized way of providing values
10 to a for loop. See PEP 234. There's a new built-in function iter()
11 to return an iterator. There's a new protocol to get the next value
12 from an iterator using the next() method (in Python) or the
13 tp_iternext slot (in C). There's a new protocol to get iterators
14 using the __iter__() method (in Python) or the tp_iter slot (in C).
15 Iterating (i.e. a for loop) over a dictionary generates its keys.
16 Iterating over a file generates its lines.
17
Tim Petersf553f892001-05-01 20:45:31 +000018- The following functions were generalized to work nicely with iterator
19 arguments:
Tim Peters0e57abf2001-05-02 07:39:38 +000020 filter()
21 list()
Tim Peters4e9afdc2001-05-03 23:54:49 +000022 map()
Tim Petersc3074532001-05-03 07:00:32 +000023 max()
24 min()
Tim Petersf553f892001-05-01 20:45:31 +000025
26
Guido van Rossumffe13be2001-04-16 18:46:45 +000027What's New in Python 2.1 (final)?
28=================================
29
30We only changed a few things since the last release candidate, all in
31Python library code:
32
33- A bug in the locale module was fixed that affected locales which
34 define no grouping for numeric formatting.
35
36- A few bugs in the weakref module's implementations of weak
37 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
38 and the test suite was updated to check for these bugs.
39
40- An old bug in the os.path.walk() function (introduced in Python
41 2.0!) was fixed: a non-existent file would cause an exception
42 instead of being ignored.
43
44- Fixed a few bugs in the new symtable module found by Neil Norwitz's
45 PyChecker.
46
47
Guido van Rossum5b08f132001-04-16 02:05:23 +000048What's New in Python 2.1c2?
49===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +000050
Guido van Rossum5b08f132001-04-16 02:05:23 +000051A flurry of small changes, and one showstopper fixed in the nick of
52time made it necessary to release another release candidate. The list
53here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +000054
Guido van Rossum5b08f132001-04-16 02:05:23 +000055Core
Guido van Rossum4fb60362001-04-13 00:46:14 +000056
Guido van Rossum5b08f132001-04-16 02:05:23 +000057- Tim discovered a nasty bug in the dictionary code, caused by
58 PyDict_Next() calling dict_resize(), and the GC code's use of
59 PyDict_Next() violating an assumption in dict_items(). This was
60 fixed with considerable amounts of band-aid, but the net effect is a
61 saner and more robust implementation.
62
63- Made a bunch of symbols static that were accidentally global.
64
65Build and Ports
66
67- The setup.py script didn't check for a new enough version of zlib
68 (1.1.3 is needed). Now it does.
69
70- Changed "make clean" target to also remove shared libraries.
71
72- Added a more general warning about the SGI Irix optimizer to README.
73
74Library
75
76- Fix a bug in urllib.basejoin("http://host", "../file.html") which
77 omitted the slash between host and file.html.
78
79- The mailbox module's _Mailbox class contained a completely broken
80 and undocumented seek() method. Ripped it out.
81
82- Fixed a bunch of typos in various library modules (urllib2, smtpd,
83 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
84
85- Fixed a few last-minute bugs in unittest.
86
87Extensions
88
89- Reverted the patch to the OpenSSL code in socketmodule.c to support
90 RAND_status() and the EGD, and the subsequent patch that tried to
91 fix it for pre-0.9.5 versions; the problem with the patch is that on
92 some systems it issues a warning whenever socket is imported, and
93 that's unacceptable.
94
95Tests
96
97- Fixed the pickle tests to work with "import test.test_pickle".
98
99- Tweaked test_locale.py to actually run the test Windows.
100
101- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
102 not "wb" (which is not a valid mode at all).
103
104- Fix pstats browser crashes. Import readline if it exists to make
105 the user interface nicer.
106
107- Add "import thread" to the top of test modules that import the
108 threading module (test_asynchat and test_threadedtempfile). This
109 prevents test failures caused by a broken threading module resulting
110 from a previously caught failed import.
111
112- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
113 needed on some platforms (e.g. Solaris 8) when the tests are run
114 twice in succession.
115
116- Skip rather than fail test_sunaudiodev if no audio device is found.
117
118
119What's New in Python 2.1c1?
120===========================
121
122This list was significantly updated when 2.1c2 was released; the 2.1c1
123release didn't mention most changes that were actually part of 2.1c1:
124
125Legal
126
127- Copyright was assigned to the Python Software Foundation (PSF) and a
128 PSF license (very similar to the CNRI license) was added.
129
130- The CNRI copyright notice was updated to include 2001.
131
132Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000133
Guido van Rossumc9932722001-04-12 02:31:27 +0000134- After a public outcry, assignment to __debug__ is no longer illegal;
135 instead, a warning is issued. It will become illegal in 2.2.
136
Guido van Rossum5b08f132001-04-16 02:05:23 +0000137- Fixed a core dump with "%#x" % 0, and changed the semantics so that
138 "%#x" now always prepends "0x", even if the value is zero.
139
140- Fixed some nits in the bytecode compiler.
141
142- Fixed core dumps when calling certain kinds of non-functions.
143
144- Fixed various core dumps caused by reference count bugs.
145
146Build and Ports
147
148- Use INSTALL_SCRIPT to install script files.
149
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000150- New port: SCO Unixware 7, by Billy G. Allie.
151
Guido van Rossum5b08f132001-04-16 02:05:23 +0000152- Updated RISCOS port.
153
154- Updated BeOS port and notes.
155
156- Various other porting problems resolved.
157
158Library
159
160- The TERMIOS and SOCKET modules are now truly obsolete and
161 unnecessary. Their symbols are incorporated in the termios and
162 socket modules.
163
164- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
165 better tests for pickling.
166
167- threading: make Condition.wait() robust against KeyboardInterrupt.
168
169- zipfile: add support to zipfile to support opening an archive
170 represented by an open file rather than a file name. Fix bug where
171 the archive was not properly closed. Fixed a bug in this bugfix
172 where flush() was called for a read-only file.
173
174- imputil: added an uninstall() method to the ImportManager.
175
176- Canvas: fixed bugs in lower() and tkraise() methods.
177
178- SocketServer: API change (added overridable close_request() method)
179 so that the TCP server can explicitly close the request.
180
181- pstats: Eric Raymond added a simple interactive statistics browser,
182 invoked when the module is run as a script.
183
184- locale: fixed a problem in format().
185
186- webbrowser: made it work when the BROWSER environment variable has a
187 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
188 KDE 2. Fixed some other nits.
189
190- unittest: changes to allow using a different exception than
191 AssertionError, and added a few more function aliases. Some other
192 small changes.
193
194- urllib, urllib2: fixed redirect problems and a coupleof other nits.
195
196- asynchat: fixed a critical bug in asynchat that slipped through the
197 2.1b2 release. Fixed another rare bug.
198
199- Fix some unqualified except: clauses (always a bad code example).
200
201XML
202
203- pyexpat: new API get_version_string().
204
205- Fixed some minidom bugs.
206
207Extensions
208
209- Fixed a core dump in _weakref. Removed the weakref.mapping()
210 function (it adds nothing to the API).
211
212- Rationalized the use of header files in the readline module, to make
213 it compile (albeit with some warnings) with the very recent readline
214 4.2, without breaking for earlier versions.
215
216- Hopefully fixed a buffering problem in linuxaudiodev.
217
218- Attempted a fix to make the OpenSSL support in the socket module
219 work again with pre-0.9.5 versions of OpenSSL.
220
221Tests
222
223- Added a test case for asynchat and asyncore.
224
225- Removed coupling between tests where one test failing could break
226 another.
227
228Tools
229
230- Ping added an interactive help browser to pydoc, fixed some nits
231 in the rest of the pydoc code, and added some features to his
232 inspect module.
233
234- An updated python-mode.el version 4.1 which integrates Ken
235 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
236 much nicer in XEmacs and Emacs. When stepping through your program
237 with pdb, in either the shell window or the *Python* window, the
238 source file and line will be tracked by an arrow. Very cool!
239
240- IDLE: syntax warnings in interactive mode are changed into errors.
241
242- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +0000243 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +0000244
245- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000246
Barry Warsaw11e89c72001-04-11 20:37:57 +0000247
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000248What's New in Python 2.1 beta 2?
249================================
250
Guido van Rossum053ae352001-03-22 14:17:21 +0000251(Unlisted are many fixed bugs, more documentation, etc.)
252
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000253Core language, builtins, and interpreter
254
Guido van Rossum053ae352001-03-22 14:17:21 +0000255- The nested scopes work (enabled by "from __future__ import
256 nested_scopes") is completed; in particular, the future now extends
257 into code executed through exec, eval() and execfile(), and into the
258 interactive interpreter.
259
260- When calling a base class method (e.g. BaseClass.__init__(self)),
261 this is now allowed even if self is not strictly spoken a class
262 instance (e.g. when using metaclasses or the Don Beaudry hook).
263
264- Slice objects are now comparable but not hashable; this prevents
265 dict[:] from being accepted but meaningless.
266
267- Complex division is now calculated using less braindead algorithms.
268 This doesn't change semantics except it's more likely to give useful
269 results in extreme cases. Complex repr() now uses full precision
270 like float repr().
271
272- sgmllib.py now calls handle_decl() for simple <!...> declarations.
273
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000274- It is illegal to assign to the name __debug__, which is set when the
275 interpreter starts. It is effectively a compile-time constant.
276
277- A warning will be issued if a global statement for a variable
278 follows a use or assignment of that variable.
279
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000280Standard library
281
Guido van Rossum053ae352001-03-22 14:17:21 +0000282- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
283 inspired by JUnit), is now part of the standard library. You now
284 have a choice of two testing frameworks: unittest requires you to
285 write testcases as separate code, doctest gathers them from
286 docstrings. Both approaches have their advantages and
287 disadvantages.
288
289- A new module Tix was added, which wraps the Tix extension library
290 for Tk. With that module, it is not necessary to statically link
291 Tix with _tkinter, since Tix will be loaded with Tcl's "package
292 require" command. See Demo/tix/.
293
294- tzparse.py is now obsolete.
295
296- In gzip.py, the seek() and tell() methods are removed -- they were
297 non-functional anyway, and it's better if callers can test for their
298 existence with hasattr().
299
300Python/C API
301
302- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
303 that's already in the dictionary during a PyDict_Next() iteration.
304 This used to fail occasionally when a dictionary resize operation
305 could be triggered that would rehash all the keys. All other
306 modifications to the dictionary are still off-limits during a
307 PyDict_Next() iteration!
308
309- New extended APIs related to passing compiler variables around.
310
311- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
312 implement isinstance() and issubclass().
313
314- Py_BuildValue() now has a "D" conversion to create a Python complex
315 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000316
Fred Drake4e262a92001-03-22 18:26:47 +0000317- Extensions types which support weak references must now set the
318 field allocated for the weak reference machinery to NULL themselves;
319 this is done to avoid the cost of checking each object for having a
320 weakly referencable type in PyObject_INIT(), since most types are
321 not weakly referencable.
322
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000323- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
324 free variables and cell variables to and from the frame's f_locals.
325
326- Variants of several functions defined in pythonrun.h have been added
327 to support the nested_scopes future statement. The variants all end
328 in Flags and take an extra argument, a PyCompilerFlags *; examples:
329 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
330 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +0000331 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000332
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000333Distutils
334
335- the sdist command now writes a PKG-INFO file, as described in PEP 241,
336 into the release tree.
337
Tim Peters0e57abf2001-05-02 07:39:38 +0000338- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000339 (an uninstaller, more customization of the installer's display)
340
341- from Jack Jansen: added Mac-specific code to generate a dialog for
342 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +0000343 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000344 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +0000345
346- added 'platforms' and 'keywords' to the set of metadata that can be
347 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000348
349- applied patches from Jason Tishler to make the compiler class work with
350 Cygwin.
351
352
Tim Peters2fe289a2001-03-01 22:19:38 +0000353What's New in Python 2.1 beta 1?
354================================
Tim Petersd66595f2001-02-04 03:09:53 +0000355
356Core language, builtins, and interpreter
357
Guido van Rossum9d0fbde2001-03-02 14:00:32 +0000358- Following an outcry from the community about the amount of code
359 broken by the nested scopes feature introduced in 2.1a2, we decided
360 to make this feature optional, and to wait until Python 2.2 (or at
361 least 6 months) to make it standard. The option can be enabled on a
362 per-module basis by adding "from __future__ import nested_scopes" at
363 the beginning of a module (before any other statements, but after
364 comments and an optional docstring). See PEP 236 (Back to the
365 __future__) for a description of the __future__ statement. PEP 227
366 (Statically Nested Scopes) has been updated to reflect this change,
367 and to clarify the semantics in a number of endcases.
368
369- The nested scopes code, when enabled, has been hardened, and most
370 bugs and memory leaks in it have been fixed.
371
372- Compile-time warnings are now generated for a number of conditions
373 that will break or change in meaning when nested scopes are enabled:
374
375 - Using "from...import *" or "exec" without in-clause in a function
376 scope that also defines a lambda or nested function with one or
377 more free (non-local) variables. The presence of the import* or
378 bare exec makes it impossible for the compiler to determine the
379 exact set of local variables in the outer scope, which makes it
380 impossible to determine the bindings for free variables in the
381 inner scope. To avoid the warning about import *, change it into
382 an import of explicitly name object, or move the import* statement
383 to the global scope; to avoid the warning about bare exec, use
384 exec...in... (a good idea anyway -- there's a possibility that
385 bare exec will be deprecated in the future).
386
387 - Use of a global variable in a nested scope with the same name as a
388 local variable in a surrounding scope. This will change in
389 meaning with nested scopes: the name in the inner scope will
390 reference the variable in the outer scope rather than the global
391 of the same name. To avoid the warning, either rename the outer
392 variable, or use a global statement in the inner function.
393
Neil Schemenauera35c6882001-02-27 04:45:05 +0000394- An optional object allocator has been included. This allocator is
395 optimized for Python objects and should be faster and use less memory
396 than the standard system allocator. It is not enabled by default
397 because of possible thread safety problems. The allocator is only
398 protected by the Python interpreter lock and it is possible that some
399 extension modules require a thread safe allocator. The object
400 allocator can be enabled by providing the "--with-pymalloc" option to
401 configure.
402
Tim Petersd66595f2001-02-04 03:09:53 +0000403Standard library
404
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000405- pyexpat now detects the expat version if expat.h defines it. A
406 number of additional handlers are provided, which are only available
407 since expat 1.95. In addition, the methods SetParamEntityParsing and
408 GetInputContext of Parser objects are available with 1.95.x
409 only. Parser objects now provide the ordered_attributes and
410 specified_attributes attributes. A new module expat.model was added,
411 which offers a number of additional constants if 1.95.x is used.
412
413- xml.dom offers the new functions registerDOMImplementation and
414 getDOMImplementation.
415
416- xml.dom.minidom offers a toprettyxml method. A number of DOM
417 conformance issues have been resolved. In particular, Element now
418 has an hasAttributes method, and the handling of namespaces was
419 improved.
420
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000421- Ka-Ping Yee contributed two new modules: inspect.py, a module for
422 getting information about live Python code, and pydoc.py, a module
423 for interactively converting docstrings to HTML or text.
424 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +0000425 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +0000426 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
427 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000428
Tim Peters1eff7962001-03-01 02:31:33 +0000429- New library module difflib.py, primarily packaging the SequenceMatcher
430 class at the heart of the popular ndiff.py file-comparison tool.
431
432- doctest.py (a framework for verifying Python code examples in docstrings)
433 is now part of the std library.
434
Tim Petersd66595f2001-02-04 03:09:53 +0000435Windows changes
436
Guido van Rossume3955a82001-03-02 14:05:59 +0000437- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
438 small GUI that lets you browse the module docstrings using your
439 default web browser.
440
Tim Peters1eff7962001-03-01 02:31:33 +0000441- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
442 Platforms) is implemented. See
443
444 http://python.sourceforge.net/peps/pep-0235.html
445
446 for full details, especially the "Current Lower-Left Semantics" section.
447 The new Windows import rules are simpler than before:
448
449 A. If the PYTHONCASEOK environment variable exists, same as
450 before: silently accept the first case-insensitive match of any
451 kind; raise ImportError if none found.
452
453 B. Else search sys.path for the first case-sensitive match; raise
454 ImportError if none found.
455
456 The same rules have been implented on other platforms with case-
457 insensitive but case-preserving filesystems too (including Cygwin, and
458 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +0000459
Tim Peters25a9ce32001-02-19 07:06:36 +0000460- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
461 what it's supposed to do (and does do under NT and 2000) via direct
462 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +0000463 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +0000464 all Win9x systems before.
465
Tim Peters1eff7962001-03-01 02:31:33 +0000466- Build: Subproject _test (effectively) renamed to _testcapi.
467
Tim Peters2fe289a2001-03-01 22:19:38 +0000468New platforms
469
470- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
471 Thanks to Steven Majewski!
472
473- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
474 Tishler!
475
Guido van Rossum9089b272001-03-02 06:49:50 +0000476- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
477 Schwertberger! See RISCOS/README for more information -- it seems
478 that because of the bizarre filename conventions on RISCOS, no port
479 to that platform is easy. Note that the new variable os.endsep is
480 silently supported in order to make life easier on this platform,
481 but we don't advertise it because it's not worth for most folks to
482 care about RISCOS portability.
483
Tim Peters25a9ce32001-02-19 07:06:36 +0000484
Tim Petersd7b5e882001-01-25 03:36:26 +0000485What's New in Python 2.1 alpha 2?
486=================================
Tim Peters40ead762001-01-27 05:35:26 +0000487
Tim Petersd7b5e882001-01-25 03:36:26 +0000488Core language, builtins, and interpreter
489
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000490- Scopes nest. If a name is used in a function or class, but is not
491 local, the definition in the nearest enclosing function scope will
492 be used. One consequence of this change is that lambda statements
493 could reference variables in the namespaces where the lambda is
494 defined. In some unusual cases, this change will break code.
495
496 In all previous version of Python, names were resolved in exactly
497 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000498 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000499 function A is defined within a function B, the names bound in B are
500 not visible in A. The new rules make names bound in B visible in A,
501 unless A contains a name binding that hides the binding in B.
502
503 Section 4.1 of the reference manual describes the new scoping rules
504 in detail. The test script in Lib/test/test_scope.py demonstrates
505 some of the effects of the change.
506
507 The new rules will cause existing code to break if it defines nested
508 functions where an outer function has local variables with the same
509 name as globals or builtins used by the inner function. Example:
510
511 def munge(str):
512 def helper(x):
513 return str(x)
514 if type(str) != type(''):
515 str = helper(str)
516 return str.strip()
517
518 Under the old rules, the name str in helper() is bound to the
519 builtin function str(). Under the new rules, it will be bound to
520 the argument named str and an error will occur when helper() is
521 called.
522
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000523- The compiler will report a SyntaxError if "from ... import *" occurs
524 in a function or class scope. The language reference has documented
525 that this case is illegal, but the compiler never checked for it.
526 The recent introduction of nested scope makes the meaning of this
527 form of name binding ambiguous. In a future release, the compiler
528 may allow this form when there is no possibility of ambiguity.
529
Tim Peters40ead762001-01-27 05:35:26 +0000530- repr(string) is easier to read, now using hex escapes instead of octal,
531 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
532
533 >>> "\texample \r\n" + chr(0) + chr(255)
534 '\texample \r\n\x00\xff' # in 2.1
535 '\011example \015\012\000\377' # in 2.0
536
Moshe Zadka6af0ce02001-01-29 06:41:00 +0000537- Functions are now compared and hashed by identity, not by value, since
538 the func_code attribute is writable.
539
Fred Drakefb9d7122001-02-01 20:00:40 +0000540- Weak references (PEP 205) have been added. This involves a few
541 changes in the core, an extension module (_weakref), and a Python
542 module (weakref). The weakref module is the public interface. It
543 includes support for "explicit" weak references, proxy objects, and
544 mappings with weakly held values.
545
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000546- A 'continue' statement can now appear in a try block within the body
547 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +0000548 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000549
Tim Petersd7b5e882001-01-25 03:36:26 +0000550Standard library
551
Barry Warsaw30dbd142001-01-31 22:14:01 +0000552- mailbox.py now has a new class, PortableUnixMailbox which is
553 identical to UnixMailbox but uses a more portable scheme for
554 determining From_ separators. Also, the constructors for all the
555 classes in this module have a new optional `factory' argument, which
556 is a callable used when new message classes must be instantiated by
557 the next() method.
558
Tim Petersd7b5e882001-01-25 03:36:26 +0000559- random.py is now self-contained, and offers all the functionality of
560 the now-deprecated whrandom.py. See the docs for details. random.py
561 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +0000562 and restoring the internal state of the generator; and jumpahead(n),
563 for quickly forcing the internal state to be the same as if n calls to
564 random() had been made. The latter is particularly useful for multi-
565 threaded programs, creating one instance of the random.Random() class for
566 each thread, then using .jumpahead() to force each instance to use a
567 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +0000568
Tim Peters0de88fc2001-02-01 04:59:18 +0000569- random.py's seed() function is new. For bit-for-bit compatibility with
570 prior releases, use the whseed function instead. The new seed function
571 addresses two problems: (1) The old function couldn't produce more than
572 about 2**24 distinct internal states; the new one about 2**45 (the best
573 that can be done in the Wichmann-Hill generator). (2) The old function
574 sometimes produced identical internal states when passed distinct
575 integers, and there was no simple way to predict when that would happen;
576 the new one guarantees to produce distinct internal states for all
577 arguments in [0, 27814431486576L).
578
Jeremy Hylton4c4fda02001-02-02 03:29:24 +0000579- The socket module now supports raw packets on Linux. The socket
580 family is AF_PACKET.
581
Tim Peters9ea17ac2001-02-02 05:57:15 +0000582- test_capi.py is a start at running tests of the Python C API. The tests
583 are implemented by the new Modules/_testmodule.c.
584
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000585- A new extension module, _symtable, provides provisional access to the
586 internal symbol table used by the Python compiler. A higher-level
587 interface will be added on top of _symtable in a future release.
588
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +0000589- Removed the obsolete soundex module.
590
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000591- xml.dom.minidom now uses the standard DOM exceptions. Node supports
592 the isSameNode method; NamedNodeMap the get method.
593
594- xml.sax.expatreader supports the lexical handler property; it
595 generates comment, startCDATA, and endCDATA events.
596
Tim Petersee826f82001-01-31 19:39:44 +0000597Windows changes
598
599- Build procedure: the zlib project is built in a different way that
600 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +0000601 the zlib binary used. See PCbuild\readme.txt for details. Your old
602 zlib-related directories can be deleted; you'll need to download fresh
603 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +0000604
Tim Peters9ea17ac2001-02-02 05:57:15 +0000605- Build: New subproject _test for the benefit of test_capi.py (see above).
606
Tim Petersb16c56f2001-02-02 21:24:51 +0000607- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
608 interface to some Python compiler internals).
609
610- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +0000611 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +0000612
Tim Petersa3a3a032000-11-30 05:22:44 +0000613What's New in Python 2.1 alpha 1?
614=================================
615
616Core language, builtins, and interpreter
617
Marc-André Lemburgebb195b2001-01-20 10:34:52 +0000618- There is a new Unicode companion to the PyObject_Str() API
619 called PyObject_Unicode(). It behaves in the same way as the
620 former, but assures that the returned value is an Unicode object
621 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +0000622
Guido van Rossumf98eda02001-01-17 15:54:45 +0000623- The comparison operators support "rich comparison overloading" (PEP
624 207). C extension types can provide a rich comparison function in
625 the new tp_richcompare slot in the type object. The cmp() function
626 and the C function PyObject_Compare() first try the new rich
627 comparison operators before trying the old 3-way comparison. There
628 is also a new C API PyObject_RichCompare() (which also falls back on
629 the old 3-way comparison, but does not constrain the outcome of the
630 rich comparison to a Boolean result).
631
632 The rich comparison function takes two objects (at least one of
633 which is guaranteed to have the type that provided the function) and
634 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
635 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
636 object, which may be NotImplemented (in which case the tp_compare
637 slot function is used as a fallback, if defined).
638
639 Classes can overload individual comparison operators by defining one
640 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +0000641 __ge__. There are no explicit "reflected argument" versions of
642 these; instead, __lt__ and __gt__ are each other's reflection,
643 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
644 reflection (similar at the C level). No other implications are
645 made; in particular, Python does not assume that == is the Boolean
646 inverse of !=, or that < is the Boolean inverse of >=. This makes
647 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +0000648
649 Classes or types that want to implement (in)equality tests but not
650 the ordering operators (i.e. unordered types) should implement ==
651 and !=, and raise an error for the ordering operators.
652
Guido van Rossuma88479f2001-01-18 14:28:08 +0000653 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +0000654 Boolean; e.g. a matrix type might want to return a matrix of bits
655 for A < B, giving elementwise comparisons. Such types should ensure
656 that any interpretation of their value in a Boolean context raises
657 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
658 at the C level) to always raise an exception.
659
Guido van Rossuma88479f2001-01-18 14:28:08 +0000660- Complex numbers use rich comparisons to define == and != but raise
661 an exception for <, <=, > and >=. Unfortunately, this also means
662 that cmp() of two complex numbers raises an exception when the two
663 numbers differ. Since it is not mathematically meaningful to compare
664 complex numbers except for equality, I hope that this doesn't break
665 too much code.
666
Tim Peters3389f192001-02-18 08:48:49 +0000667- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +0000668 not defined by the language, other than that it's arbitrary but
669 consistent (see the Reference Manual). An implementation detail changed
670 in 2.1a1 such that None now compares less than any other object. Code
671 relying on this new behavior (like code that relied on the previous
672 behavior) does so at its own risk.
673
Barry Warsaw573b5412001-01-15 20:43:18 +0000674- Functions and methods now support getting and setting arbitrarily
675 named attributes (PEP 232). Functions have a new __dict__
676 (a.k.a. func_dict) which hold the function attributes. Methods get
677 and set attributes on their underlying im_func. It is a TypeError
678 to set an attribute on a bound method.
679
Guido van Rossum051e3352001-01-15 19:11:10 +0000680- The xrange() object implementation has been improved so that
681 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
682 limitation that in this case len(xrange(sys.maxint)) can't be
683 calculated, but the common idiom "for i in xrange(sys.maxint)" will
684 work fine as long as the index i doesn't actually reach 2**31.
685 (Python uses regular ints for sequence and string indices; fixing
686 that is much more work.)
687
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000688- Two changes to from...import:
689
Guido van Rossumba381232001-02-03 15:06:40 +0000690 1) "from M import X" now works even if (after loading module M)
691 sys.modules['M'] is not a real module; it's basically a getattr()
692 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000693
694 2) "from M import *" now looks for M.__all__ to decide which names to
695 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
696 filters out names starting with '_' as before. Whether or not
697 __all__ exists, there's no restriction on the type of M.
698
Guido van Rossumf61f1662001-01-10 20:13:55 +0000699- File objects have a new method, xreadlines(). This is the fastest
700 way to iterate over all lines in a file:
701
702 for line in file.xreadlines():
703 ...do something to line...
704
705 See the xreadlines module (mentioned below) for how to do this for
706 other file-like objects.
707
708- Even if you don't use file.xreadlines(), you may expect a speedup on
709 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +0000710 quite a bit in platform-specific ways: on systems (like Linux) that
711 support flockfile(), getc_unlocked(), and funlockfile(), those are
712 used by default. On systems (like Windows) without getc_unlocked(),
713 a complicated (but still thread-safe) method using fgets() is used by
714 default.
715
Tim Petersd52269b2001-01-25 06:23:18 +0000716 You can force use of the fgets() method by #define'ing
717 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +0000718 getc_unlocked()).
719
Tim Petersd52269b2001-01-25 06:23:18 +0000720 You can force fgets() not to be used by #define'ing
721 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +0000722 test_bufio.py fails -- and let us know if it does!).
723
724- In addition, the fileinput module, while still slower than the other
725 methods on most platforms, has been sped up too, by using
726 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +0000727
728- Support for run-time warnings has been added, including a new
729 command line option (-W) to specify the disposition of warnings.
730 See the description of the warnings module below.
731
732- Extensive changes have been made to the coercion code. This mostly
733 affects extension modules (which can now implement mixed-type
734 numerical operators without having to use coercion), but
735 occasionally, in boundary cases the coercion semantics have changed
736 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +0000737 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +0000738 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +0000739 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +0000740
Guido van Rossumf98eda02001-01-17 15:54:45 +0000741- In connection with the coercion changes, a new built-in singleton
742 object, NotImplemented is defined. This can be returned for
743 operations that wish to indicate they are not implemented for a
744 particular combination of arguments. From C, this is
745 Py_NotImplemented.
746
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +0000747- The interpreter accepts now bytecode files on the command line even
748 if they do not have a .pyc or .pyo extension. On Linux, after executing
749
Martin v. Löwise214baa2001-02-04 22:37:56 +0000750import imp,sys,string
751magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
752reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
753open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +0000754
755 any byte code file can be used as an executable (i.e. as an argument
756 to execve(2)).
757
Tim Peters9940b802000-12-01 07:59:35 +0000758- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +0000759 character. In 1.6 and earlier, they never produced a sign,
760 and raised an error if the value of the long was too large
761 to fit in a Python int. In 2.0, they produced a sign if and
762 only if too large to fit in an int. This was inconsistent
763 across platforms (because the size of an int varies across
764 platforms), and inconsistent with hex() and oct(). Example:
765
766 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +0000767 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +0000768 'ffffffbe' # in 2.0 and before, on 32-bit machines
769 >>> hex(-0x42L)
770 '-0x42L' # in all versions of Python
771
Tim Peters9940b802000-12-01 07:59:35 +0000772 The behavior of %d formats for negative Python longs remains
773 the same as in 2.0 (although in 1.6 and before, they raised
774 an error if the long didn't fit in a Python int).
775
776 %u formats don't make sense for Python longs, but are allowed
777 and treated the same as %d in 2.1. In 2.0, a negative long
778 formatted via %u produced a sign if and only if too large to
779 fit in an int. In 1.6 and earlier, a negative long formatted
780 via %u raised an error if it was too big to fit in an int.
781
Guido van Rossum3661d392000-12-12 22:10:31 +0000782- Dictionary objects have an odd new method, popitem(). This removes
783 an arbitrary item from the dictionary and returns it (in the form of
784 a (key, value) pair). This can be useful for algorithms that use a
785 dictionary as a bag of "to do" items and repeatedly need to pick one
786 item. Such algorithms normally end up running in quadratic time;
787 using popitem() they can usually be made to run in linear time.
788
Tim Peters36cdad12000-12-29 02:06:45 +0000789Standard library
790
Thomas Woutersfe385252001-01-19 23:16:56 +0000791- In the time module, the time argument to the functions strftime,
792 localtime, gmtime, asctime and ctime is now optional, defaulting to
793 the current time (in the local timezone).
794
Guido van Rossumda91f222001-01-15 16:36:08 +0000795- The ftplib module now defaults to passive mode, which is deemed a
796 more useful default given that clients are often inside firewalls
797 these days. Note that this could break if ftplib is used to connect
798 to a *server* that is inside a firewall, from outside; this is
799 expected to be a very rare situation. To fix that, you can call
800 ftp.set_pasv(0).
801
Martin v. Löwis10a27872001-01-13 09:54:41 +0000802- The module site now treats .pth files not only for path configuration,
803 but also supports extensions to the initialization code: Lines starting
804 with import are executed.
805
Guido van Rossumf61f1662001-01-10 20:13:55 +0000806- There's a new module, warnings, which implements a mechanism for
807 issuing and filtering warnings. There are some new built-in
808 exceptions that serve as warning categories, and a new command line
809 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
810 turns warnings into errors). warnings.warn(message[, category])
811 issues a warning message; this can also be called from C as
812 PyErr_Warn(category, message).
813
814- A new module xreadlines was added. This exports a single factory
815 function, xreadlines(). The intention is that this code is the
816 absolutely fastest way to iterate over all lines in an open
817 file(-like) object:
818
819 import xreadlines
820 for line in xreadlines.xreadlines(file):
821 ...do something to line...
822
823 This is equivalent to the previous the speed record holder using
824 file.readlines(sizehint). Note that if file is a real file object
825 (as opposed to a file-like object), this is equivalent:
826
827 for line in file.xreadlines():
828 ...do something to line...
829
Tim Peters36cdad12000-12-29 02:06:45 +0000830- The bisect module has new functions bisect_left, insort_left,
831 bisect_right and insort_right. The old names bisect and insort
832 are now aliases for bisect_right and insort_right. XXX_right
833 and XXX_left methods differ in what happens when the new element
834 compares equal to one or more elements already in the list: the
835 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +0000836 right. Code that doesn't care where equal elements end up should
837 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +0000838
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +0000839- The new curses.panel module wraps the panel library that forms part
840 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
841
Guido van Rossumf61f1662001-01-10 20:13:55 +0000842- The SocketServer module now sets the allow_reuse_address flag by
843 default in the TCPServer class.
844
845- A new function, sys._getframe(), returns the stack frame pointer of
846 the caller. This is intended only as a building block for
847 higher-level mechanisms such as string interpolation.
848
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000849- The pyexpat module supports a number of new handlers, which are
850 available only in expat 1.2. If invocation of a callback fails, it
851 will report an additional frame in the traceback. Parser objects
852 participate now in garbage collection. If expat reports an unknown
853 encoding, pyexpat will try to use a Python codec; that works only
854 for single-byte charsets. The parser type objects is exposed as
855 XMLParserObject.
856
857- xml.dom now offers standard definitions for symbolic node type and
858 exception code constants, and a hierarchy of DOM exceptions. minidom
859 was adjusted to use them.
860
861- The conformance of xml.dom.minidom to the DOM specification was
862 improved. It detects a number of additional error cases; the
863 previous/next relationship works even when the tree is modified;
864 Node supports the normalize() method; NamedNodeMap, DocumentType and
865 DOMImplementation classes were added; Element supports the
866 hasAttribute and hasAttributeNS methods; and Text supports the splitText
867 method.
868
Guido van Rossumf61f1662001-01-10 20:13:55 +0000869Build issues
870
Guido van Rossum1e33bdc2001-01-23 03:17:00 +0000871- For Unix (and Unix-compatible) builds, configuration and building of
872 extension modules is now greatly automated. Rather than having to
873 edit the Modules/Setup file to indicate which modules should be
874 built and where their include files and libraries are, a
875 distutils-based setup.py script now takes care of building most
876 extension modules. All extension modules built this way are built
877 as shared libraries. Only a few modules that must be linked
878 statically are still listed in the Setup file; you won't need to
879 edit their configuration.
880
881- Python should now build out of the box on Cygwin. If it doesn't,
882 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +0000883
884- Python now always uses its own (renamed) implementation of getopt()
885 -- there's too much variation among C library getopt()
886 implementations.
887
888- C++ compilers are better supported; the CXX macro is always set to a
889 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +0000890
Tim Petersd92dfe02000-12-12 01:18:41 +0000891Windows changes
892
893- select module: By default under Windows, a select() call
894 can specify no more than 64 sockets. Python now boosts
895 this Microsoft default to 512. If you need even more than
896 that, see the MS docs (you'll need to #define FD_SETSIZE
897 and recompile Python from source).
898
Guido van Rossumf61f1662001-01-10 20:13:55 +0000899- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
900 subdirectory is no more!
901
Tim Petersa3a3a032000-11-30 05:22:44 +0000902
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000903What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +0000904=========================
Guido van Rossum61000331997-08-15 04:39:58 +0000905
Guido van Rossum8ed602b2000-09-01 22:34:33 +0000906Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000907changes are in the file HISTORY. If you are making the jump directly
908from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
909HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +0000910
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000911Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
912the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
913http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +0000914
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000915--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +0000916
917======================================================================
918
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000919What's new in 2.0 (since release candidate 1)?
920==============================================
921
922Standard library
923
924- The copy_reg module was modified to clarify its intended use: to
925 register pickle support for extension types, not for classes.
926 pickle() will raise a TypeError if it is passed a class.
927
928- Fixed a bug in gettext's "normalize and expand" code that prevented
929 it from finding an existing .mo file.
930
931- Restored support for HTTP/0.9 servers in httplib.
932
Tim Peters989b7b92000-10-16 20:24:53 +0000933- The math module was changed to stop raising OverflowError in case of
934 underflow, and return 0 instead in underflow cases. Whether Python
935 used to raise OverflowError in case of underflow was platform-
936 dependent (it did when the platform math library set errno to ERANGE
937 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000938
939- Fixed a bug in StringIO that occurred when the file position was not
940 at the end of the file and write() was called with enough data to
941 extend past the end of the file.
942
943- Fixed a bug that caused Tkinter error messages to get lost on
944 Windows. The bug was fixed by replacing direct use of
945 interp->result with Tcl_GetStringResult(interp).
946
947- Fixed bug in urllib2 that caused it to fail when it received an HTTP
948 redirect response.
949
950- Several changes were made to distutils: Some debugging code was
951 removed from util. Fixed the installer used when an external zip
952 program (like WinZip) is not found; the source code for this
953 installer is in Misc/distutils. check_lib() was modified to behave
954 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
955 test for whether installed modules are on sys.path was changed to
956 use both normcase() and normpath().
957
Jeremy Hyltond867a2c2000-10-16 20:41:38 +0000958- Several minor bugs were fixed in the xml package (the minidom,
959 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000960
961- The regression test driver (regrtest.py) behavior when invoked with
962 -l changed: It now reports a count of objects that are recognized as
963 garbage but not freed by the garbage collector.
964
Tim Peters989b7b92000-10-16 20:24:53 +0000965- The regression test for the math module was changed to test
966 exceptional behavior when the test is run in verbose mode. Python
967 cannot yet guarantee consistent exception behavior across platforms,
968 so the exception part of test_math is run only in verbose mode, and
969 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000970
971Internals
972
973- PyOS_CheckStack() has been disabled on Win64, where it caused
974 test_sre to fail.
975
976Build issues
977
978- Changed compiler flags, so that gcc is always invoked with -Wall and
979 -Wstrict-prototypes. Users compiling Python with GCC should see
980 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +0000981 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +0000982 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000983
Tim Petersa3a3a032000-11-30 05:22:44 +0000984- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000985
986Tools and other miscellany
987
988- The compiler in Tools/compiler was updated to support the new
989 language features introduced in 2.0: extended print statement, list
990 comprehensions, and augmented assignments. The new compiler should
991 also be backwards compatible with Python 1.5.2; the compiler will
992 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +0000993 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000994
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000995What's new in 2.0 release candidate 1 (since beta 2)?
996=====================================================
997
Jeremy Hylton6040aaa2000-10-09 21:27:22 +0000998What is release candidate 1?
999
1000We believe that release candidate 1 will fix all known bugs that we
1001intend to fix for the 2.0 final release. This release should be a bit
1002more stable than the previous betas. We would like to see even more
1003widespread testing before the final release, so we are producing this
1004release candidate. The final release will be exactly the same unless
1005any show-stopping (or brown bag) bugs are found by testers of the
1006release candidate.
1007
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001008All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001009to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001010
1011Core language, builtins, and interpreter
1012
1013- A bug that caused crashes when __coerce__ was used with augmented
1014 assignment, e.g. +=, was fixed.
1015
1016- Raise ZeroDivisionError when raising zero to a negative number,
1017 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1018 power operator and the result of math.pow(0.0, -2.0) will vary by
1019 platform. On Linux, it raises a ValueError.
1020
1021- A bug in Unicode string interpolation was fixed that occasionally
1022 caused errors with formats including "%%". For example, the
1023 following expression "%% %s" % u"abc" no longer raises a TypeError.
1024
1025- Compilation of deeply nested expressions raises MemoryError instead
1026 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1027
1028- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1029 rendering them useless. They are now written in binary mode again.
1030
1031Standard library
1032
1033- Keyword arguments are now accepted for most pattern and match object
1034 methods in SRE, the standard regular expression engine.
1035
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001036- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001037 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001038
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001039- Several bugs in the Unicode handling and error handling in _tkinter
1040 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001041
1042- Fix memory management errors in Merge() and Tkapp_Call() routines.
1043
1044- Several changes were made to cStringIO to make it compatible with
1045 the file-like object interface and with StringIO. If operations are
1046 performed on a closed object, an exception is raised. The truncate
1047 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001048 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001049
1050- There were many changes made to the linuxaudiodev module and its
1051 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001052 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001053
1054 Note that this module is named poorly, because it should work
1055 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001056 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001057
1058 The module now raises exceptions when errors occur instead of
1059 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1060 audio) and defines a getptr() method that calls the
1061 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1062
1063- The library_version attribute, introduced in an earlier beta, was
1064 removed because it can not be supported with early versions of the C
1065 readline library, which provides no way to determine the version at
1066 compile-time.
1067
1068- The binascii module is now enabled on Win64.
1069
Tim Peters46446d62000-10-09 21:19:31 +00001070- tokenize.py no longer suffers "recursion depth" errors when parsing
1071 programs with very long string literals.
1072
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001073Internals
1074
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001075- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001076 which is called when the interpreter starts up to determine where
1077 the standard library is installed. These vulnerabilities affect all
1078 previous versions of Python and can be exploited by setting very
1079 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1080 setuid Python script, although use of the wrapper in
1081 Misc/setuid-prog.c will eliminate the vulnerability.
1082
1083- Fixed garbage collection bugs in instance creation that were
1084 triggered when errors occurred during initialization. The solution,
1085 applied in cPickle and in PyInstance_New(), is to call
1086 PyObject_GC_Init() after the initialization of the object's
1087 container attributes is complete.
1088
1089- pyexpat adds definitions of PyModule_AddStringConstant and
1090 PyModule_AddObject if the Python version is less than 2.0, which
1091 provides compatibility with PyXML on Python 1.5.2.
1092
1093- If the platform has a bogus definition for LONG_BIT (the number of
1094 bits in a long), an error will be reported at compile time.
1095
1096- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1097 collection crashes and possibly other, unreported crashes.
1098
1099- Fixed a memory leak in _PyUnicode_Fini().
1100
1101Build issues
1102
1103- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001104 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001105 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001106
1107- The mmap.PAGESIZE constant is now initialized using sysconf when
1108 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1109
1110- The md5 file should now compile on all platforms.
1111
1112- The select module now compiles on platforms that do not define
1113 POLLRDNORM and related constants.
1114
1115- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001116 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001117
Jeremy Hylton10921202000-10-09 18:34:12 +00001118- BeOS: A number of changes were made to the build and installation
1119 process. ar-fake now operates on a directory of object files.
1120 dl_export.h is gone, and its macros now appear on the mwcc command
1121 line during build on PPC BeOS.
1122
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001123- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001124 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001125
1126- Cygwin: Support for shared libraries, Tkinter, and sockets.
1127
1128- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1129
1130Tools and other miscellany
1131
1132- Removed debugging prints from main used with freeze.
1133
Tim Peters46446d62000-10-09 21:19:31 +00001134- IDLE auto-indent no longer crashes when it encounters Unicode
1135 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001136
1137What's new in 2.0 beta 2 (since beta 1)?
1138========================================
1139
1140Core language, builtins, and interpreter
1141
Tim Peters482c0212000-09-26 06:33:09 +00001142- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001143 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001144
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001145- Add -h and -V command line options to print the usage message and
1146 Python version number and exit immediately.
1147
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001148- eval() and exec accept Unicode objects as code parameters.
1149
1150- getattr() and setattr() now also accept Unicode objects for the
1151 attribute name, which are converted to strings using the default
1152 encoding before lookup.
1153
1154- Multiplication on string and Unicode now does proper bounds
1155 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1156 string is too long."
1157
1158- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001159 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001160
Jeremy Hylton1b618592000-09-26 05:32:36 +00001161
1162Standard library and extensions
1163
Guido van Rossum5b08f132001-04-16 02:05:23 +00001164- socket module: the OpenSSL code now adds support for RAND_status()
1165 and EGD (Entropy Gathering Device).
1166
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001167- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001168 argument checking; it still takes no arguments.
1169
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001170- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001171
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001172- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001173
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001174- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001175
1176- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001177 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001178
1179- copy: Copy Unicode objects atomically.
1180
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001181- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001182
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001183- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001184
Fred Drake67233bc2000-09-26 16:40:27 +00001185- dbm: Add get() and setdefault() methods to dbm object. Add constant
1186 `library' to module that names the library used. Added doc strings
1187 and method names to error messages. Uses configure to determine
1188 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
1189 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001190
1191- distutils: Update to version 0.9.3.
1192
1193- dl: Add several dl.RTLD_ constants.
1194
1195- fpectl: Now supported on FreeBSD.
1196
1197- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
1198 found by the collector will be saved in gc.garbage. This is useful
1199 for debugging a program that creates reference cycles.
1200
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001201- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00001202 of HTTP class. Do not close socket on zero-length response. Do not
1203 crash when server sends invalid content-length header.
1204
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001205- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001206
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001207- marshal: When reading a short, sign-extend on platforms where shorts
1208 are bigger than 16 bits. When reading a long, repair the unportable
1209 sign extension that was being done for 64-bit machines. (It assumed
1210 that signed right shift sign-extends.)
1211
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001212- operator: Add contains(), invert(), __invert__() as aliases for
1213 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001214
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001215- os: Add support for popen2() and popen3() on all platforms where
1216 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001217
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001218- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00001219 clicking on a file in Explorer (or passing the file name to the
1220 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001221
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001222- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00001223 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001224
1225- pickle: Now raises ValueError when an invalid pickle that contains
1226 a non-string repr where a string repr was expected. This behavior
1227 matches cPickle.
1228
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001229- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001230
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001231- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001232
1233- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001234 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001235 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001236
1237- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001238 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001239
1240- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00001241 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00001242 few cycles during startup since the first call to
1243 setdefaultencoding() will initialize the codec registry and the
1244 encodings package.
1245
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001246- socket: Support for size hint in readlines() method of object returned
1247 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001248
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001249- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001250 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001251 is followed by whitespace.
1252
Tim Petersa3a3a032000-11-30 05:22:44 +00001253- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001254
1255- struct: Check ranges for bytes and shorts.
1256
1257- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001258 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001259
1260- Tkinter: Image objects are now guaranteed to have unique ids. Set
1261 event.delta to zero if Tk version doesn't support mousewheel.
1262 Removed some debugging prints.
1263
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001264- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001265
Fred Drake67233bc2000-09-26 16:40:27 +00001266- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001267 which works around a bug in Norton AntiVirus 2000 that leads directly
1268 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001269
1270- xml: New version detection code allows PyXML to override standard
1271 XML package if PyXML version is greater than 0.6.1.
1272
Fred Drake64bb3802000-09-26 16:21:35 +00001273- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
1274 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
1275 tree only for nodes which are sufficiently interesting to a specific
1276 application. Does not provide the HTML-specific extensions. Still
1277 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001278
Fred Drake64bb3802000-09-26 16:21:35 +00001279- xml.sax: SAX 2 support for Python, including all the handler
1280 interfaces needed to process XML 1.0 compliant XML. Some
1281 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001282
Fred Drake64bb3802000-09-26 16:21:35 +00001283- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
1284 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001285
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001286
Jeremy Hylton1b618592000-09-26 05:32:36 +00001287C API
1288
1289- Add three new convenience functions for module initialization --
1290 PyModule_AddObject(), PyModule_AddIntConstant(), and
1291 PyModule_AddStringConstant().
1292
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001293- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00001294 removed and add #error to Python.h if NULL isn't defined after
1295 #include of stdio.h.
1296
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001297- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00001298 backwards compatibility (at the source level) with old extensions.
1299
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001300- A wrapper API was added for signal() and sigaction(). Instead of
1301 either function, always use PyOS_getsig() to get a signal handler
1302 and PyOS_setsig() to set one. A new convenience typedef
1303 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001304
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001305- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00001306 internal data buffer and size of a string object -- or the default
1307 encoded version of a Unicode object.
1308
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001309- PyString_Size() and PyString_AsString() accept Unicode objects.
1310
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001311- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00001312 exists). INT_MAX and LONG_MAX will always be defined, even if
1313 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001314
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001315- PyFloat_FromString takes a second argument, pend, that was
1316 effectively useless. It is now officially useless but preserved for
1317 backwards compatibility. If the pend argument is not NULL, *pend is
1318 set to NULL.
1319
1320- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
1321 for the attribute name. See note on getattr() above.
1322
1323- A few bug fixes to argument processing for Unicode.
1324 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
1325 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
1326 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00001327 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001328
1329- Py_BuildValue accepts B format (for bgen-generated code).
1330
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001331
Jeremy Hylton1b618592000-09-26 05:32:36 +00001332Internals
1333
1334- On Unix, fix code for finding Python installation directory so that
1335 it works when argv[0] is a relative path.
1336
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00001337- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001338 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00001339 rather than by generating a copy of the object.
1340
Tim Peters482c0212000-09-26 06:33:09 +00001341- Several of the internal Unicode tables are much smaller now, and
1342 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001343
Jeremy Hylton97693b02000-09-26 17:42:51 +00001344- In the garbage collector: Fixed bug in collection of tuples. Fixed
1345 bug that caused some instances to be removed from the container set
1346 while they were still live. Fixed parsing in gc.set_debug() for
1347 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001348
1349- Fixed refcount problem in instance deallocation that only occurred
1350 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
1351
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001352- On Windows, getpythonregpath is now protected against null data in
1353 registry key.
1354
1355- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00001356 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001357
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001358
Jeremy Hylton1b618592000-09-26 05:32:36 +00001359Build and platform-specific issues
1360
1361- Better support of GNU Pth via --with-pth configure option.
1362
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001363- Python/C API now properly exposed to dynamically-loaded extension
1364 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001365
1366- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
1367 Don't define MS_SYNC to be zero when it is undefined. Added missing
1368 prototypes in posixmodule.c.
1369
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001370- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001371 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001372
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001373- Fix largefile support on older NetBSD systems and OpenBSD by adding
1374 define for TELL64.
1375
1376
1377Tools and other miscellany
1378
1379- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
1380
1381- freeze: The modulefinder now works with 2.0 opcodes.
1382
Tim Petersa3a3a032000-11-30 05:22:44 +00001383- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001384 Move hackery of sys.argv until after the Tk instance has been
1385 created, which allows the application-specific Tkinter
1386 initialization to be executed if present; also pass an explicit
1387 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00001388
Jeremy Hylton1b618592000-09-26 05:32:36 +00001389
1390What's new in 2.0 beta 1?
1391=========================
1392
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001393Source Incompatibilities
1394------------------------
1395
1396None. Note that 1.6 introduced several incompatibilities with 1.5.2,
1397such as single-argument append(), connect() and bind(), and changes to
1398str(long) and repr(float).
1399
1400
1401Binary Incompatibilities
1402------------------------
1403
1404- Third party extensions built for Python 1.5.x or 1.6 cannot be used
1405with Python 2.0; these extensions will have to be rebuilt for Python
14062.0.
1407
1408- On Windows, attempting to import a third party extension built for
1409Python 1.5.x or 1.6 results in an immediate crash; there's not much we
1410can do about this. Check your PYTHONPATH environment variable!
1411
1412- Python bytecode files (*.pyc and *.pyo) are not compatible between
1413releases.
1414
1415
1416Overview of Changes Since 1.6
1417-----------------------------
1418
1419There are many new modules (including brand new XML support through
1420the xml package, and i18n support through the gettext module); a list
1421of all new modules is included below. Lots of bugs have been fixed.
1422
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001423The process for making major new changes to the language has changed
1424since Python 1.6. Enhancements must now be documented by a Python
1425Enhancement Proposal (PEP) before they can be accepted.
1426
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001427There are several important syntax enhancements, described in more
1428detail below:
1429
1430 - Augmented assignment, e.g. x += 1
1431
1432 - List comprehensions, e.g. [x**2 for x in range(10)]
1433
1434 - Extended import statement, e.g. import Module as Name
1435
1436 - Extended print statement, e.g. print >> file, "Hello"
1437
1438Other important changes:
1439
1440 - Optional collection of cyclical garbage
1441
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001442Python Enhancement Proposal (PEP)
1443---------------------------------
1444
1445PEP stands for Python Enhancement Proposal. A PEP is a design
1446document providing information to the Python community, or describing
1447a new feature for Python. The PEP should provide a concise technical
1448specification of the feature and a rationale for the feature.
1449
1450We intend PEPs to be the primary mechanisms for proposing new
1451features, for collecting community input on an issue, and for
1452documenting the design decisions that have gone into Python. The PEP
1453author is responsible for building consensus within the community and
1454documenting dissenting opinions.
1455
1456The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001457
1458Augmented Assignment
1459--------------------
1460
1461This must have been the most-requested feature of the past years!
1462Eleven new assignment operators were added:
1463
Guido van Rossume905e952000-09-05 12:42:46 +00001464 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001465
1466For example,
1467
1468 A += B
1469
1470is similar to
1471
1472 A = A + B
1473
1474except that A is evaluated only once (relevant when A is something
1475like dict[index].attr).
1476
1477However, if A is a mutable object, A may be modified in place. Thus,
1478if A is a number or a string, A += B has the same effect as A = A+B
1479(except A is only evaluated once); but if a is a list, A += B has the
1480same effect as A.extend(B)!
1481
1482Classes and built-in object types can override the new operators in
1483order to implement the in-place behavior; the not-in-place behavior is
1484used automatically as a fallback when an object doesn't implement the
1485in-place behavior. For classes, the method name is derived from the
1486method name for the corresponding not-in-place operator by inserting
1487an 'i' in front of the name, e.g. __iadd__ implements in-place
1488__add__.
1489
1490Augmented assignment was implemented by Thomas Wouters.
1491
1492
1493List Comprehensions
1494-------------------
1495
1496This is a flexible new notation for lists whose elements are computed
1497from another list (or lists). The simplest form is:
1498
1499 [<expression> for <variable> in <sequence>]
1500
Guido van Rossum56db0952000-09-06 23:34:25 +00001501For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001502This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001503
1504You can also add a condition:
1505
1506 [<expression> for <variable> in <sequence> if <condition>]
1507
1508For example, [w for w in words if w == w.lower()] would yield the list
1509of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001510than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001511
1512You can also have nested for loops and more than one 'if' clause. For
1513example, here's a function that flattens a sequence of sequences::
1514
1515 def flatten(seq):
1516 return [x for subseq in seq for x in subseq]
1517
1518 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
1519
1520This prints
1521
1522 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
1523
1524List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001525Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001526
1527
1528Extended Import Statement
1529-------------------------
1530
1531Many people have asked for a way to import a module under a different
1532name. This can be accomplished like this:
1533
1534 import foo
1535 bar = foo
1536 del foo
1537
1538but this common idiom gets old quickly. A simple extension of the
1539import statement now allows this to be written as follows:
1540
1541 import foo as bar
1542
1543There's also a variant for 'from ... import':
1544
1545 from foo import bar as spam
1546
1547This also works with packages; e.g. you can write this:
1548
1549 import test.regrtest as regrtest
1550
1551Note that 'as' is not a new keyword -- it is recognized only in this
1552context (this is only possible because the syntax for the import
1553statement doesn't involve expressions).
1554
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001555Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001556
1557
1558Extended Print Statement
1559------------------------
1560
1561Easily the most controversial new feature, this extension to the print
1562statement adds an option to make the output go to a different file
1563than the default sys.stdout.
1564
1565For example, to write an error message to sys.stderr, you can now
1566write:
1567
1568 print >> sys.stderr, "Error: bad dog!"
1569
1570As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00001571evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001572
1573 print >> None, "Hello world"
1574
1575is equivalent to
1576
1577 print "Hello world"
1578
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001579Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001580
1581
1582Optional Collection of Cyclical Garbage
1583---------------------------------------
1584
1585Python is now equipped with a garbage collector that can hunt down
1586cyclical references between Python objects. It's no replacement for
1587reference counting; in fact, it depends on the reference counts being
1588correct, and decides that a set of objects belong to a cycle if all
1589their reference counts can be accounted for from their references to
1590each other. This devious scheme was first proposed by Eric Tiedemann,
1591and brought to implementation by Neil Schemenauer.
1592
1593There's a module "gc" that lets you control some parameters of the
1594garbage collection. There's also an option to the configure script
1595that lets you enable or disable the garbage collection. In 2.0b1,
1596it's on by default, so that we (hopefully) can collect decent user
1597experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00001598performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001599off by default in the final 2.0 release.
1600
1601
1602Smaller Changes
1603---------------
1604
1605A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
1606map(None, seq1, seq2, ...) when the sequences have the same length;
1607i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
1608the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001609zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001610
1611sys.version_info is a tuple (major, minor, micro, level, serial).
1612
1613Dictionaries have an odd new method, setdefault(key, default).
1614dict.setdefault(key, default) returns dict[key] if it exists; if not,
1615it sets dict[key] to default and returns that value. Thus:
1616
1617 dict.setdefault(key, []).append(item)
1618
1619does the same work as this common idiom:
1620
1621 if not dict.has_key(key):
1622 dict[key] = []
1623 dict[key].append(item)
1624
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001625There are two new variants of SyntaxError that are raised for
1626indentation-related errors: IndentationError and TabError.
1627
1628Changed \x to consume exactly two hex digits; see PEP 223. Added \U
1629escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001630
1631The limits on the size of expressions and file in Python source code
1632have been raised from 2**16 to 2**32. Previous versions of Python
1633were limited because the maximum argument size the Python VM accepted
1634was 2**16. This limited the size of object constructor expressions,
1635e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
1636limit was raised thanks to a patch by Charles Waldman that effectively
1637fixes the problem. It is now much more likely that you will be
1638limited by available memory than by an arbitrary limit in Python.
1639
1640The interpreter's maximum recursion depth can be modified by Python
1641programs using sys.getrecursionlimit and sys.setrecursionlimit. This
1642limit is the maximum number of recursive calls that can be made by
1643Python code. The limit exists to prevent infinite recursion from
1644overflowing the C stack and causing a core dump. The default value is
16451000. The maximum safe value for a particular platform can be found
1646by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001647
1648New Modules and Packages
1649------------------------
1650
1651atexit - for registering functions to be called when Python exits.
1652
1653imputil - Greg Stein's alternative API for writing custom import
1654hooks.
1655
1656pyexpat - an interface to the Expat XML parser, contributed by Paul
1657Prescod.
1658
1659xml - a new package with XML support code organized (so far) in three
1660subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
1661would fill a volume. There's a special feature whereby a
1662user-installed package named _xmlplus overrides the standard
1663xmlpackage; this is intended to give the XML SIG a hook to distribute
1664backwards-compatible updates to the standard xml package.
1665
1666webbrowser - a platform-independent API to launch a web browser.
1667
1668
Guido van Rossume905e952000-09-05 12:42:46 +00001669Changed Modules
1670---------------
1671
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001672array -- new methods for array objects: count, extend, index, pop, and
1673remove
1674
1675binascii -- new functions b2a_hex and a2b_hex that convert between
1676binary data and its hex representation
1677
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001678calendar -- Many new functions that support features including control
1679over which day of the week is the first day, returning strings instead
1680of printing them. Also new symbolic constants for days of week,
1681e.g. MONDAY, ..., SUNDAY.
1682
1683cgi -- FieldStorage objects have a getvalue method that works like a
1684dictionary's get method and returns the value attribute of the object.
1685
1686ConfigParser -- The parser object has new methods has_option,
1687remove_section, remove_option, set, and write. They allow the module
1688to be used for writing config files as well as reading them.
1689
1690ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00001691optionally support the RFC 959 REST command.
1692
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001693gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00001694
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001695httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
1696the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00001697
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001698locale -- implement getdefaultlocale for Win32 and Macintosh
1699
1700marshal -- no longer dumps core when marshaling deeply nested or
1701recursive data structures
1702
1703os -- new functions isatty, seteuid, setegid, setreuid, setregid
1704
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001705os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
1706support under Unix.
1707
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001708os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001709
1710os.path -- fix semantics of os.path.commonprefix
1711
1712smtplib -- support for sending very long messages
1713
1714socket -- new function getfqdn()
1715
1716readline -- new functions to read, write and truncate history files.
1717The readline section of the library reference manual contains an
1718example.
1719
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001720select -- add interface to poll system call
1721
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001722shutil -- new copyfileobj function
1723
1724SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
1725HTTP server.
1726
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001727Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001728
1729urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00001730e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001731
1732whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00001733
1734
1735Obsolete Modules
1736----------------
1737
1738None. However note that 1.6 made a whole slew of modules obsolete:
1739stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
1740poly, zmod, strop, util, whatsound.
1741
1742
1743Changed, New, Obsolete Tools
1744----------------------------
1745
Tim Peters8b092332000-09-05 20:15:25 +00001746None.
Guido van Rossume905e952000-09-05 12:42:46 +00001747
1748
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001749C-level Changes
1750---------------
1751
1752Several cleanup jobs were carried out throughout the source code.
1753
1754All C code was converted to ANSI C; we got rid of all uses of the
1755Py_PROTO() macro, which makes the header files a lot more readable.
1756
1757Most of the portability hacks were moved to a new header file,
1758pyport.h; several other new header files were added and some old
1759header files were removed, in an attempt to create a more rational set
1760of header files. (Few of these ever need to be included explicitly;
1761they are all included by Python.h.)
1762
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001763Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001764and Win64, especially for the new Intel Itanium processor. Mick also
1765added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001766
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001767The C APIs to return an object's size have been update to consistently
1768use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
1769previous versions, the abstract interfaces used PyXXX_Length and the
1770concrete interfaces used PyXXX_Size. The old names,
1771e.g. PyObject_Length, are still available for backwards compatibility
1772at the API level, but are deprecated.
1773
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001774The PyOS_CheckStack function has been implemented on Windows by
1775Fredrik Lundh. It prevents Python from failing with a stack overflow
1776on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001777
1778The GC changes resulted in creation of two new slots on object,
1779tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00001780the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001781
1782The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00001783C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001784
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001785PyErr_Format has been updated to automatically calculate the size of
1786the buffer needed to hold the formatted result string. This change
1787prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001788
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001789New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00001790
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001791PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
1792that are the same as their non-Ex counterparts except they take an
1793extra flag argument that tells them to close the file when done.
1794
1795XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00001796
Tim Peters8b092332000-09-05 20:15:25 +00001797
1798Windows Changes
1799---------------
1800
1801New popen2/popen3/peopen4 in os module (see Changed Modules above).
1802
1803os.popen is much more usable on Windows 95 and 98. See Microsoft
1804Knowledge Base article Q150956. The Win9x workaround described there
1805is implemented by the new w9xpopen.exe helper in the root of your
1806Python installation. Note that Python uses this internally; it is not
1807a standalone program.
1808
1809Administrator privileges are no longer required to install Python
1810on Windows NT or Windows 2000. If you have administrator privileges,
1811Python's registry info will be written under HKEY_LOCAL_MACHINE.
1812Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00001813under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00001814uses of Python, but will prevent some advanced uses from working
1815(for example, running a Python script as an NT service, or possibly
1816from CGI).
1817
1818[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
1819installer; instead, it installs the needed Tcl/Tk files directly in the
1820Python directory. If you already have a Tcl/Tk installation, this
1821wastes some disk space (about 4 Megs) but avoids problems with
1822conflicting Tcl/Tk installations, and makes it much easier for Python
1823to ensure that Tcl/Tk can find all its files.
1824
1825[This was new in 1.6] The Windows installer now installs by default in
1826\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
1827
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001828
1829Updates to the changes between 1.5.2 and 1.6
1830--------------------------------------------
1831
1832The 1.6 NEWS file can't be changed after the release is done, so here
1833is some late-breaking news:
1834
1835New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
1836and changes to getlocale() and setlocale().
1837
1838The new module is now enabled per default.
1839
1840It is not true that the encodings codecs cannot be used for normal
1841strings: the string.encode() (which is also present on 8-bit strings
1842!) allows using them for 8-bit strings too, e.g. to convert files from
1843cp1252 (Windows) to latin-1 or vice-versa.
1844
1845Japanese codecs are available from Tamito KAJIYAMA:
1846http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
1847
1848
Guido van Rossumab9d6f01998-08-10 22:01:13 +00001849======================================================================