blob: bf63854180d2a077c3f50e31b343ecebf2beea30 [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 Peters15d81ef2001-05-04 04:39:21 +000025 reduce()
Tim Peters3e067572001-05-04 04:43:42 +000026 XXX TODO string.join(), unicode.join()
27 XXX TODO tuple()
28 XXX TODO zip()
Tim Petersf553f892001-05-01 20:45:31 +000029
Guido van Rossumffe13be2001-04-16 18:46:45 +000030What's New in Python 2.1 (final)?
31=================================
32
33We only changed a few things since the last release candidate, all in
34Python library code:
35
36- A bug in the locale module was fixed that affected locales which
37 define no grouping for numeric formatting.
38
39- A few bugs in the weakref module's implementations of weak
40 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
41 and the test suite was updated to check for these bugs.
42
43- An old bug in the os.path.walk() function (introduced in Python
44 2.0!) was fixed: a non-existent file would cause an exception
45 instead of being ignored.
46
47- Fixed a few bugs in the new symtable module found by Neil Norwitz's
48 PyChecker.
49
50
Guido van Rossum5b08f132001-04-16 02:05:23 +000051What's New in Python 2.1c2?
52===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +000053
Guido van Rossum5b08f132001-04-16 02:05:23 +000054A flurry of small changes, and one showstopper fixed in the nick of
55time made it necessary to release another release candidate. The list
56here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +000057
Guido van Rossum5b08f132001-04-16 02:05:23 +000058Core
Guido van Rossum4fb60362001-04-13 00:46:14 +000059
Guido van Rossum5b08f132001-04-16 02:05:23 +000060- Tim discovered a nasty bug in the dictionary code, caused by
61 PyDict_Next() calling dict_resize(), and the GC code's use of
62 PyDict_Next() violating an assumption in dict_items(). This was
63 fixed with considerable amounts of band-aid, but the net effect is a
64 saner and more robust implementation.
65
66- Made a bunch of symbols static that were accidentally global.
67
68Build and Ports
69
70- The setup.py script didn't check for a new enough version of zlib
71 (1.1.3 is needed). Now it does.
72
73- Changed "make clean" target to also remove shared libraries.
74
75- Added a more general warning about the SGI Irix optimizer to README.
76
77Library
78
79- Fix a bug in urllib.basejoin("http://host", "../file.html") which
80 omitted the slash between host and file.html.
81
82- The mailbox module's _Mailbox class contained a completely broken
83 and undocumented seek() method. Ripped it out.
84
85- Fixed a bunch of typos in various library modules (urllib2, smtpd,
86 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
87
88- Fixed a few last-minute bugs in unittest.
89
90Extensions
91
92- Reverted the patch to the OpenSSL code in socketmodule.c to support
93 RAND_status() and the EGD, and the subsequent patch that tried to
94 fix it for pre-0.9.5 versions; the problem with the patch is that on
95 some systems it issues a warning whenever socket is imported, and
96 that's unacceptable.
97
98Tests
99
100- Fixed the pickle tests to work with "import test.test_pickle".
101
102- Tweaked test_locale.py to actually run the test Windows.
103
104- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
105 not "wb" (which is not a valid mode at all).
106
107- Fix pstats browser crashes. Import readline if it exists to make
108 the user interface nicer.
109
110- Add "import thread" to the top of test modules that import the
111 threading module (test_asynchat and test_threadedtempfile). This
112 prevents test failures caused by a broken threading module resulting
113 from a previously caught failed import.
114
115- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
116 needed on some platforms (e.g. Solaris 8) when the tests are run
117 twice in succession.
118
119- Skip rather than fail test_sunaudiodev if no audio device is found.
120
121
122What's New in Python 2.1c1?
123===========================
124
125This list was significantly updated when 2.1c2 was released; the 2.1c1
126release didn't mention most changes that were actually part of 2.1c1:
127
128Legal
129
130- Copyright was assigned to the Python Software Foundation (PSF) and a
131 PSF license (very similar to the CNRI license) was added.
132
133- The CNRI copyright notice was updated to include 2001.
134
135Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000136
Guido van Rossumc9932722001-04-12 02:31:27 +0000137- After a public outcry, assignment to __debug__ is no longer illegal;
138 instead, a warning is issued. It will become illegal in 2.2.
139
Guido van Rossum5b08f132001-04-16 02:05:23 +0000140- Fixed a core dump with "%#x" % 0, and changed the semantics so that
141 "%#x" now always prepends "0x", even if the value is zero.
142
143- Fixed some nits in the bytecode compiler.
144
145- Fixed core dumps when calling certain kinds of non-functions.
146
147- Fixed various core dumps caused by reference count bugs.
148
149Build and Ports
150
151- Use INSTALL_SCRIPT to install script files.
152
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000153- New port: SCO Unixware 7, by Billy G. Allie.
154
Guido van Rossum5b08f132001-04-16 02:05:23 +0000155- Updated RISCOS port.
156
157- Updated BeOS port and notes.
158
159- Various other porting problems resolved.
160
161Library
162
163- The TERMIOS and SOCKET modules are now truly obsolete and
164 unnecessary. Their symbols are incorporated in the termios and
165 socket modules.
166
167- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
168 better tests for pickling.
169
170- threading: make Condition.wait() robust against KeyboardInterrupt.
171
172- zipfile: add support to zipfile to support opening an archive
173 represented by an open file rather than a file name. Fix bug where
174 the archive was not properly closed. Fixed a bug in this bugfix
175 where flush() was called for a read-only file.
176
177- imputil: added an uninstall() method to the ImportManager.
178
179- Canvas: fixed bugs in lower() and tkraise() methods.
180
181- SocketServer: API change (added overridable close_request() method)
182 so that the TCP server can explicitly close the request.
183
184- pstats: Eric Raymond added a simple interactive statistics browser,
185 invoked when the module is run as a script.
186
187- locale: fixed a problem in format().
188
189- webbrowser: made it work when the BROWSER environment variable has a
190 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
191 KDE 2. Fixed some other nits.
192
193- unittest: changes to allow using a different exception than
194 AssertionError, and added a few more function aliases. Some other
195 small changes.
196
197- urllib, urllib2: fixed redirect problems and a coupleof other nits.
198
199- asynchat: fixed a critical bug in asynchat that slipped through the
200 2.1b2 release. Fixed another rare bug.
201
202- Fix some unqualified except: clauses (always a bad code example).
203
204XML
205
206- pyexpat: new API get_version_string().
207
208- Fixed some minidom bugs.
209
210Extensions
211
212- Fixed a core dump in _weakref. Removed the weakref.mapping()
213 function (it adds nothing to the API).
214
215- Rationalized the use of header files in the readline module, to make
216 it compile (albeit with some warnings) with the very recent readline
217 4.2, without breaking for earlier versions.
218
219- Hopefully fixed a buffering problem in linuxaudiodev.
220
221- Attempted a fix to make the OpenSSL support in the socket module
222 work again with pre-0.9.5 versions of OpenSSL.
223
224Tests
225
226- Added a test case for asynchat and asyncore.
227
228- Removed coupling between tests where one test failing could break
229 another.
230
231Tools
232
233- Ping added an interactive help browser to pydoc, fixed some nits
234 in the rest of the pydoc code, and added some features to his
235 inspect module.
236
237- An updated python-mode.el version 4.1 which integrates Ken
238 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
239 much nicer in XEmacs and Emacs. When stepping through your program
240 with pdb, in either the shell window or the *Python* window, the
241 source file and line will be tracked by an arrow. Very cool!
242
243- IDLE: syntax warnings in interactive mode are changed into errors.
244
245- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +0000246 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +0000247
248- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000249
Barry Warsaw11e89c72001-04-11 20:37:57 +0000250
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000251What's New in Python 2.1 beta 2?
252================================
253
Guido van Rossum053ae352001-03-22 14:17:21 +0000254(Unlisted are many fixed bugs, more documentation, etc.)
255
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000256Core language, builtins, and interpreter
257
Guido van Rossum053ae352001-03-22 14:17:21 +0000258- The nested scopes work (enabled by "from __future__ import
259 nested_scopes") is completed; in particular, the future now extends
260 into code executed through exec, eval() and execfile(), and into the
261 interactive interpreter.
262
263- When calling a base class method (e.g. BaseClass.__init__(self)),
264 this is now allowed even if self is not strictly spoken a class
265 instance (e.g. when using metaclasses or the Don Beaudry hook).
266
267- Slice objects are now comparable but not hashable; this prevents
268 dict[:] from being accepted but meaningless.
269
270- Complex division is now calculated using less braindead algorithms.
271 This doesn't change semantics except it's more likely to give useful
272 results in extreme cases. Complex repr() now uses full precision
273 like float repr().
274
275- sgmllib.py now calls handle_decl() for simple <!...> declarations.
276
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000277- It is illegal to assign to the name __debug__, which is set when the
278 interpreter starts. It is effectively a compile-time constant.
279
280- A warning will be issued if a global statement for a variable
281 follows a use or assignment of that variable.
282
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000283Standard library
284
Guido van Rossum053ae352001-03-22 14:17:21 +0000285- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
286 inspired by JUnit), is now part of the standard library. You now
287 have a choice of two testing frameworks: unittest requires you to
288 write testcases as separate code, doctest gathers them from
289 docstrings. Both approaches have their advantages and
290 disadvantages.
291
292- A new module Tix was added, which wraps the Tix extension library
293 for Tk. With that module, it is not necessary to statically link
294 Tix with _tkinter, since Tix will be loaded with Tcl's "package
295 require" command. See Demo/tix/.
296
297- tzparse.py is now obsolete.
298
299- In gzip.py, the seek() and tell() methods are removed -- they were
300 non-functional anyway, and it's better if callers can test for their
301 existence with hasattr().
302
303Python/C API
304
305- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
306 that's already in the dictionary during a PyDict_Next() iteration.
307 This used to fail occasionally when a dictionary resize operation
308 could be triggered that would rehash all the keys. All other
309 modifications to the dictionary are still off-limits during a
310 PyDict_Next() iteration!
311
312- New extended APIs related to passing compiler variables around.
313
314- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
315 implement isinstance() and issubclass().
316
317- Py_BuildValue() now has a "D" conversion to create a Python complex
318 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000319
Fred Drake4e262a92001-03-22 18:26:47 +0000320- Extensions types which support weak references must now set the
321 field allocated for the weak reference machinery to NULL themselves;
322 this is done to avoid the cost of checking each object for having a
323 weakly referencable type in PyObject_INIT(), since most types are
324 not weakly referencable.
325
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000326- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
327 free variables and cell variables to and from the frame's f_locals.
328
329- Variants of several functions defined in pythonrun.h have been added
330 to support the nested_scopes future statement. The variants all end
331 in Flags and take an extra argument, a PyCompilerFlags *; examples:
332 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
333 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +0000334 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000335
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000336Distutils
337
338- the sdist command now writes a PKG-INFO file, as described in PEP 241,
339 into the release tree.
340
Tim Peters0e57abf2001-05-02 07:39:38 +0000341- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000342 (an uninstaller, more customization of the installer's display)
343
344- from Jack Jansen: added Mac-specific code to generate a dialog for
345 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +0000346 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000347 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +0000348
349- added 'platforms' and 'keywords' to the set of metadata that can be
350 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000351
352- applied patches from Jason Tishler to make the compiler class work with
353 Cygwin.
354
355
Tim Peters2fe289a2001-03-01 22:19:38 +0000356What's New in Python 2.1 beta 1?
357================================
Tim Petersd66595f2001-02-04 03:09:53 +0000358
359Core language, builtins, and interpreter
360
Guido van Rossum9d0fbde2001-03-02 14:00:32 +0000361- Following an outcry from the community about the amount of code
362 broken by the nested scopes feature introduced in 2.1a2, we decided
363 to make this feature optional, and to wait until Python 2.2 (or at
364 least 6 months) to make it standard. The option can be enabled on a
365 per-module basis by adding "from __future__ import nested_scopes" at
366 the beginning of a module (before any other statements, but after
367 comments and an optional docstring). See PEP 236 (Back to the
368 __future__) for a description of the __future__ statement. PEP 227
369 (Statically Nested Scopes) has been updated to reflect this change,
370 and to clarify the semantics in a number of endcases.
371
372- The nested scopes code, when enabled, has been hardened, and most
373 bugs and memory leaks in it have been fixed.
374
375- Compile-time warnings are now generated for a number of conditions
376 that will break or change in meaning when nested scopes are enabled:
377
378 - Using "from...import *" or "exec" without in-clause in a function
379 scope that also defines a lambda or nested function with one or
380 more free (non-local) variables. The presence of the import* or
381 bare exec makes it impossible for the compiler to determine the
382 exact set of local variables in the outer scope, which makes it
383 impossible to determine the bindings for free variables in the
384 inner scope. To avoid the warning about import *, change it into
385 an import of explicitly name object, or move the import* statement
386 to the global scope; to avoid the warning about bare exec, use
387 exec...in... (a good idea anyway -- there's a possibility that
388 bare exec will be deprecated in the future).
389
390 - Use of a global variable in a nested scope with the same name as a
391 local variable in a surrounding scope. This will change in
392 meaning with nested scopes: the name in the inner scope will
393 reference the variable in the outer scope rather than the global
394 of the same name. To avoid the warning, either rename the outer
395 variable, or use a global statement in the inner function.
396
Neil Schemenauera35c6882001-02-27 04:45:05 +0000397- An optional object allocator has been included. This allocator is
398 optimized for Python objects and should be faster and use less memory
399 than the standard system allocator. It is not enabled by default
400 because of possible thread safety problems. The allocator is only
401 protected by the Python interpreter lock and it is possible that some
402 extension modules require a thread safe allocator. The object
403 allocator can be enabled by providing the "--with-pymalloc" option to
404 configure.
405
Tim Petersd66595f2001-02-04 03:09:53 +0000406Standard library
407
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000408- pyexpat now detects the expat version if expat.h defines it. A
409 number of additional handlers are provided, which are only available
410 since expat 1.95. In addition, the methods SetParamEntityParsing and
411 GetInputContext of Parser objects are available with 1.95.x
412 only. Parser objects now provide the ordered_attributes and
413 specified_attributes attributes. A new module expat.model was added,
414 which offers a number of additional constants if 1.95.x is used.
415
416- xml.dom offers the new functions registerDOMImplementation and
417 getDOMImplementation.
418
419- xml.dom.minidom offers a toprettyxml method. A number of DOM
420 conformance issues have been resolved. In particular, Element now
421 has an hasAttributes method, and the handling of namespaces was
422 improved.
423
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000424- Ka-Ping Yee contributed two new modules: inspect.py, a module for
425 getting information about live Python code, and pydoc.py, a module
426 for interactively converting docstrings to HTML or text.
427 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +0000428 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +0000429 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
430 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000431
Tim Peters1eff7962001-03-01 02:31:33 +0000432- New library module difflib.py, primarily packaging the SequenceMatcher
433 class at the heart of the popular ndiff.py file-comparison tool.
434
435- doctest.py (a framework for verifying Python code examples in docstrings)
436 is now part of the std library.
437
Tim Petersd66595f2001-02-04 03:09:53 +0000438Windows changes
439
Guido van Rossume3955a82001-03-02 14:05:59 +0000440- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
441 small GUI that lets you browse the module docstrings using your
442 default web browser.
443
Tim Peters1eff7962001-03-01 02:31:33 +0000444- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
445 Platforms) is implemented. See
446
447 http://python.sourceforge.net/peps/pep-0235.html
448
449 for full details, especially the "Current Lower-Left Semantics" section.
450 The new Windows import rules are simpler than before:
451
452 A. If the PYTHONCASEOK environment variable exists, same as
453 before: silently accept the first case-insensitive match of any
454 kind; raise ImportError if none found.
455
456 B. Else search sys.path for the first case-sensitive match; raise
457 ImportError if none found.
458
459 The same rules have been implented on other platforms with case-
460 insensitive but case-preserving filesystems too (including Cygwin, and
461 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +0000462
Tim Peters25a9ce32001-02-19 07:06:36 +0000463- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
464 what it's supposed to do (and does do under NT and 2000) via direct
465 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +0000466 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +0000467 all Win9x systems before.
468
Tim Peters1eff7962001-03-01 02:31:33 +0000469- Build: Subproject _test (effectively) renamed to _testcapi.
470
Tim Peters2fe289a2001-03-01 22:19:38 +0000471New platforms
472
473- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
474 Thanks to Steven Majewski!
475
476- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
477 Tishler!
478
Guido van Rossum9089b272001-03-02 06:49:50 +0000479- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
480 Schwertberger! See RISCOS/README for more information -- it seems
481 that because of the bizarre filename conventions on RISCOS, no port
482 to that platform is easy. Note that the new variable os.endsep is
483 silently supported in order to make life easier on this platform,
484 but we don't advertise it because it's not worth for most folks to
485 care about RISCOS portability.
486
Tim Peters25a9ce32001-02-19 07:06:36 +0000487
Tim Petersd7b5e882001-01-25 03:36:26 +0000488What's New in Python 2.1 alpha 2?
489=================================
Tim Peters40ead762001-01-27 05:35:26 +0000490
Tim Petersd7b5e882001-01-25 03:36:26 +0000491Core language, builtins, and interpreter
492
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000493- Scopes nest. If a name is used in a function or class, but is not
494 local, the definition in the nearest enclosing function scope will
495 be used. One consequence of this change is that lambda statements
496 could reference variables in the namespaces where the lambda is
497 defined. In some unusual cases, this change will break code.
498
499 In all previous version of Python, names were resolved in exactly
500 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000501 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000502 function A is defined within a function B, the names bound in B are
503 not visible in A. The new rules make names bound in B visible in A,
504 unless A contains a name binding that hides the binding in B.
505
506 Section 4.1 of the reference manual describes the new scoping rules
507 in detail. The test script in Lib/test/test_scope.py demonstrates
508 some of the effects of the change.
509
510 The new rules will cause existing code to break if it defines nested
511 functions where an outer function has local variables with the same
512 name as globals or builtins used by the inner function. Example:
513
514 def munge(str):
515 def helper(x):
516 return str(x)
517 if type(str) != type(''):
518 str = helper(str)
519 return str.strip()
520
521 Under the old rules, the name str in helper() is bound to the
522 builtin function str(). Under the new rules, it will be bound to
523 the argument named str and an error will occur when helper() is
524 called.
525
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000526- The compiler will report a SyntaxError if "from ... import *" occurs
527 in a function or class scope. The language reference has documented
528 that this case is illegal, but the compiler never checked for it.
529 The recent introduction of nested scope makes the meaning of this
530 form of name binding ambiguous. In a future release, the compiler
531 may allow this form when there is no possibility of ambiguity.
532
Tim Peters40ead762001-01-27 05:35:26 +0000533- repr(string) is easier to read, now using hex escapes instead of octal,
534 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
535
536 >>> "\texample \r\n" + chr(0) + chr(255)
537 '\texample \r\n\x00\xff' # in 2.1
538 '\011example \015\012\000\377' # in 2.0
539
Moshe Zadka6af0ce02001-01-29 06:41:00 +0000540- Functions are now compared and hashed by identity, not by value, since
541 the func_code attribute is writable.
542
Fred Drakefb9d7122001-02-01 20:00:40 +0000543- Weak references (PEP 205) have been added. This involves a few
544 changes in the core, an extension module (_weakref), and a Python
545 module (weakref). The weakref module is the public interface. It
546 includes support for "explicit" weak references, proxy objects, and
547 mappings with weakly held values.
548
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000549- A 'continue' statement can now appear in a try block within the body
550 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +0000551 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000552
Tim Petersd7b5e882001-01-25 03:36:26 +0000553Standard library
554
Barry Warsaw30dbd142001-01-31 22:14:01 +0000555- mailbox.py now has a new class, PortableUnixMailbox which is
556 identical to UnixMailbox but uses a more portable scheme for
557 determining From_ separators. Also, the constructors for all the
558 classes in this module have a new optional `factory' argument, which
559 is a callable used when new message classes must be instantiated by
560 the next() method.
561
Tim Petersd7b5e882001-01-25 03:36:26 +0000562- random.py is now self-contained, and offers all the functionality of
563 the now-deprecated whrandom.py. See the docs for details. random.py
564 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +0000565 and restoring the internal state of the generator; and jumpahead(n),
566 for quickly forcing the internal state to be the same as if n calls to
567 random() had been made. The latter is particularly useful for multi-
568 threaded programs, creating one instance of the random.Random() class for
569 each thread, then using .jumpahead() to force each instance to use a
570 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +0000571
Tim Peters0de88fc2001-02-01 04:59:18 +0000572- random.py's seed() function is new. For bit-for-bit compatibility with
573 prior releases, use the whseed function instead. The new seed function
574 addresses two problems: (1) The old function couldn't produce more than
575 about 2**24 distinct internal states; the new one about 2**45 (the best
576 that can be done in the Wichmann-Hill generator). (2) The old function
577 sometimes produced identical internal states when passed distinct
578 integers, and there was no simple way to predict when that would happen;
579 the new one guarantees to produce distinct internal states for all
580 arguments in [0, 27814431486576L).
581
Jeremy Hylton4c4fda02001-02-02 03:29:24 +0000582- The socket module now supports raw packets on Linux. The socket
583 family is AF_PACKET.
584
Tim Peters9ea17ac2001-02-02 05:57:15 +0000585- test_capi.py is a start at running tests of the Python C API. The tests
586 are implemented by the new Modules/_testmodule.c.
587
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000588- A new extension module, _symtable, provides provisional access to the
589 internal symbol table used by the Python compiler. A higher-level
590 interface will be added on top of _symtable in a future release.
591
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +0000592- Removed the obsolete soundex module.
593
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000594- xml.dom.minidom now uses the standard DOM exceptions. Node supports
595 the isSameNode method; NamedNodeMap the get method.
596
597- xml.sax.expatreader supports the lexical handler property; it
598 generates comment, startCDATA, and endCDATA events.
599
Tim Petersee826f82001-01-31 19:39:44 +0000600Windows changes
601
602- Build procedure: the zlib project is built in a different way that
603 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +0000604 the zlib binary used. See PCbuild\readme.txt for details. Your old
605 zlib-related directories can be deleted; you'll need to download fresh
606 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +0000607
Tim Peters9ea17ac2001-02-02 05:57:15 +0000608- Build: New subproject _test for the benefit of test_capi.py (see above).
609
Tim Petersb16c56f2001-02-02 21:24:51 +0000610- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
611 interface to some Python compiler internals).
612
613- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +0000614 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +0000615
Tim Petersa3a3a032000-11-30 05:22:44 +0000616What's New in Python 2.1 alpha 1?
617=================================
618
619Core language, builtins, and interpreter
620
Marc-André Lemburgebb195b2001-01-20 10:34:52 +0000621- There is a new Unicode companion to the PyObject_Str() API
622 called PyObject_Unicode(). It behaves in the same way as the
623 former, but assures that the returned value is an Unicode object
624 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +0000625
Guido van Rossumf98eda02001-01-17 15:54:45 +0000626- The comparison operators support "rich comparison overloading" (PEP
627 207). C extension types can provide a rich comparison function in
628 the new tp_richcompare slot in the type object. The cmp() function
629 and the C function PyObject_Compare() first try the new rich
630 comparison operators before trying the old 3-way comparison. There
631 is also a new C API PyObject_RichCompare() (which also falls back on
632 the old 3-way comparison, but does not constrain the outcome of the
633 rich comparison to a Boolean result).
634
635 The rich comparison function takes two objects (at least one of
636 which is guaranteed to have the type that provided the function) and
637 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
638 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
639 object, which may be NotImplemented (in which case the tp_compare
640 slot function is used as a fallback, if defined).
641
642 Classes can overload individual comparison operators by defining one
643 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +0000644 __ge__. There are no explicit "reflected argument" versions of
645 these; instead, __lt__ and __gt__ are each other's reflection,
646 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
647 reflection (similar at the C level). No other implications are
648 made; in particular, Python does not assume that == is the Boolean
649 inverse of !=, or that < is the Boolean inverse of >=. This makes
650 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +0000651
652 Classes or types that want to implement (in)equality tests but not
653 the ordering operators (i.e. unordered types) should implement ==
654 and !=, and raise an error for the ordering operators.
655
Guido van Rossuma88479f2001-01-18 14:28:08 +0000656 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +0000657 Boolean; e.g. a matrix type might want to return a matrix of bits
658 for A < B, giving elementwise comparisons. Such types should ensure
659 that any interpretation of their value in a Boolean context raises
660 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
661 at the C level) to always raise an exception.
662
Guido van Rossuma88479f2001-01-18 14:28:08 +0000663- Complex numbers use rich comparisons to define == and != but raise
664 an exception for <, <=, > and >=. Unfortunately, this also means
665 that cmp() of two complex numbers raises an exception when the two
666 numbers differ. Since it is not mathematically meaningful to compare
667 complex numbers except for equality, I hope that this doesn't break
668 too much code.
669
Tim Peters3389f192001-02-18 08:48:49 +0000670- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +0000671 not defined by the language, other than that it's arbitrary but
672 consistent (see the Reference Manual). An implementation detail changed
673 in 2.1a1 such that None now compares less than any other object. Code
674 relying on this new behavior (like code that relied on the previous
675 behavior) does so at its own risk.
676
Barry Warsaw573b5412001-01-15 20:43:18 +0000677- Functions and methods now support getting and setting arbitrarily
678 named attributes (PEP 232). Functions have a new __dict__
679 (a.k.a. func_dict) which hold the function attributes. Methods get
680 and set attributes on their underlying im_func. It is a TypeError
681 to set an attribute on a bound method.
682
Guido van Rossum051e3352001-01-15 19:11:10 +0000683- The xrange() object implementation has been improved so that
684 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
685 limitation that in this case len(xrange(sys.maxint)) can't be
686 calculated, but the common idiom "for i in xrange(sys.maxint)" will
687 work fine as long as the index i doesn't actually reach 2**31.
688 (Python uses regular ints for sequence and string indices; fixing
689 that is much more work.)
690
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000691- Two changes to from...import:
692
Guido van Rossumba381232001-02-03 15:06:40 +0000693 1) "from M import X" now works even if (after loading module M)
694 sys.modules['M'] is not a real module; it's basically a getattr()
695 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000696
697 2) "from M import *" now looks for M.__all__ to decide which names to
698 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
699 filters out names starting with '_' as before. Whether or not
700 __all__ exists, there's no restriction on the type of M.
701
Guido van Rossumf61f1662001-01-10 20:13:55 +0000702- File objects have a new method, xreadlines(). This is the fastest
703 way to iterate over all lines in a file:
704
705 for line in file.xreadlines():
706 ...do something to line...
707
708 See the xreadlines module (mentioned below) for how to do this for
709 other file-like objects.
710
711- Even if you don't use file.xreadlines(), you may expect a speedup on
712 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +0000713 quite a bit in platform-specific ways: on systems (like Linux) that
714 support flockfile(), getc_unlocked(), and funlockfile(), those are
715 used by default. On systems (like Windows) without getc_unlocked(),
716 a complicated (but still thread-safe) method using fgets() is used by
717 default.
718
Tim Petersd52269b2001-01-25 06:23:18 +0000719 You can force use of the fgets() method by #define'ing
720 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +0000721 getc_unlocked()).
722
Tim Petersd52269b2001-01-25 06:23:18 +0000723 You can force fgets() not to be used by #define'ing
724 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +0000725 test_bufio.py fails -- and let us know if it does!).
726
727- In addition, the fileinput module, while still slower than the other
728 methods on most platforms, has been sped up too, by using
729 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +0000730
731- Support for run-time warnings has been added, including a new
732 command line option (-W) to specify the disposition of warnings.
733 See the description of the warnings module below.
734
735- Extensive changes have been made to the coercion code. This mostly
736 affects extension modules (which can now implement mixed-type
737 numerical operators without having to use coercion), but
738 occasionally, in boundary cases the coercion semantics have changed
739 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +0000740 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +0000741 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +0000742 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +0000743
Guido van Rossumf98eda02001-01-17 15:54:45 +0000744- In connection with the coercion changes, a new built-in singleton
745 object, NotImplemented is defined. This can be returned for
746 operations that wish to indicate they are not implemented for a
747 particular combination of arguments. From C, this is
748 Py_NotImplemented.
749
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +0000750- The interpreter accepts now bytecode files on the command line even
751 if they do not have a .pyc or .pyo extension. On Linux, after executing
752
Martin v. Löwise214baa2001-02-04 22:37:56 +0000753import imp,sys,string
754magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
755reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
756open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +0000757
758 any byte code file can be used as an executable (i.e. as an argument
759 to execve(2)).
760
Tim Peters9940b802000-12-01 07:59:35 +0000761- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +0000762 character. In 1.6 and earlier, they never produced a sign,
763 and raised an error if the value of the long was too large
764 to fit in a Python int. In 2.0, they produced a sign if and
765 only if too large to fit in an int. This was inconsistent
766 across platforms (because the size of an int varies across
767 platforms), and inconsistent with hex() and oct(). Example:
768
769 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +0000770 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +0000771 'ffffffbe' # in 2.0 and before, on 32-bit machines
772 >>> hex(-0x42L)
773 '-0x42L' # in all versions of Python
774
Tim Peters9940b802000-12-01 07:59:35 +0000775 The behavior of %d formats for negative Python longs remains
776 the same as in 2.0 (although in 1.6 and before, they raised
777 an error if the long didn't fit in a Python int).
778
779 %u formats don't make sense for Python longs, but are allowed
780 and treated the same as %d in 2.1. In 2.0, a negative long
781 formatted via %u produced a sign if and only if too large to
782 fit in an int. In 1.6 and earlier, a negative long formatted
783 via %u raised an error if it was too big to fit in an int.
784
Guido van Rossum3661d392000-12-12 22:10:31 +0000785- Dictionary objects have an odd new method, popitem(). This removes
786 an arbitrary item from the dictionary and returns it (in the form of
787 a (key, value) pair). This can be useful for algorithms that use a
788 dictionary as a bag of "to do" items and repeatedly need to pick one
789 item. Such algorithms normally end up running in quadratic time;
790 using popitem() they can usually be made to run in linear time.
791
Tim Peters36cdad12000-12-29 02:06:45 +0000792Standard library
793
Thomas Woutersfe385252001-01-19 23:16:56 +0000794- In the time module, the time argument to the functions strftime,
795 localtime, gmtime, asctime and ctime is now optional, defaulting to
796 the current time (in the local timezone).
797
Guido van Rossumda91f222001-01-15 16:36:08 +0000798- The ftplib module now defaults to passive mode, which is deemed a
799 more useful default given that clients are often inside firewalls
800 these days. Note that this could break if ftplib is used to connect
801 to a *server* that is inside a firewall, from outside; this is
802 expected to be a very rare situation. To fix that, you can call
803 ftp.set_pasv(0).
804
Martin v. Löwis10a27872001-01-13 09:54:41 +0000805- The module site now treats .pth files not only for path configuration,
806 but also supports extensions to the initialization code: Lines starting
807 with import are executed.
808
Guido van Rossumf61f1662001-01-10 20:13:55 +0000809- There's a new module, warnings, which implements a mechanism for
810 issuing and filtering warnings. There are some new built-in
811 exceptions that serve as warning categories, and a new command line
812 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
813 turns warnings into errors). warnings.warn(message[, category])
814 issues a warning message; this can also be called from C as
815 PyErr_Warn(category, message).
816
817- A new module xreadlines was added. This exports a single factory
818 function, xreadlines(). The intention is that this code is the
819 absolutely fastest way to iterate over all lines in an open
820 file(-like) object:
821
822 import xreadlines
823 for line in xreadlines.xreadlines(file):
824 ...do something to line...
825
826 This is equivalent to the previous the speed record holder using
827 file.readlines(sizehint). Note that if file is a real file object
828 (as opposed to a file-like object), this is equivalent:
829
830 for line in file.xreadlines():
831 ...do something to line...
832
Tim Peters36cdad12000-12-29 02:06:45 +0000833- The bisect module has new functions bisect_left, insort_left,
834 bisect_right and insort_right. The old names bisect and insort
835 are now aliases for bisect_right and insort_right. XXX_right
836 and XXX_left methods differ in what happens when the new element
837 compares equal to one or more elements already in the list: the
838 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +0000839 right. Code that doesn't care where equal elements end up should
840 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +0000841
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +0000842- The new curses.panel module wraps the panel library that forms part
843 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
844
Guido van Rossumf61f1662001-01-10 20:13:55 +0000845- The SocketServer module now sets the allow_reuse_address flag by
846 default in the TCPServer class.
847
848- A new function, sys._getframe(), returns the stack frame pointer of
849 the caller. This is intended only as a building block for
850 higher-level mechanisms such as string interpolation.
851
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000852- The pyexpat module supports a number of new handlers, which are
853 available only in expat 1.2. If invocation of a callback fails, it
854 will report an additional frame in the traceback. Parser objects
855 participate now in garbage collection. If expat reports an unknown
856 encoding, pyexpat will try to use a Python codec; that works only
857 for single-byte charsets. The parser type objects is exposed as
858 XMLParserObject.
859
860- xml.dom now offers standard definitions for symbolic node type and
861 exception code constants, and a hierarchy of DOM exceptions. minidom
862 was adjusted to use them.
863
864- The conformance of xml.dom.minidom to the DOM specification was
865 improved. It detects a number of additional error cases; the
866 previous/next relationship works even when the tree is modified;
867 Node supports the normalize() method; NamedNodeMap, DocumentType and
868 DOMImplementation classes were added; Element supports the
869 hasAttribute and hasAttributeNS methods; and Text supports the splitText
870 method.
871
Guido van Rossumf61f1662001-01-10 20:13:55 +0000872Build issues
873
Guido van Rossum1e33bdc2001-01-23 03:17:00 +0000874- For Unix (and Unix-compatible) builds, configuration and building of
875 extension modules is now greatly automated. Rather than having to
876 edit the Modules/Setup file to indicate which modules should be
877 built and where their include files and libraries are, a
878 distutils-based setup.py script now takes care of building most
879 extension modules. All extension modules built this way are built
880 as shared libraries. Only a few modules that must be linked
881 statically are still listed in the Setup file; you won't need to
882 edit their configuration.
883
884- Python should now build out of the box on Cygwin. If it doesn't,
885 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +0000886
887- Python now always uses its own (renamed) implementation of getopt()
888 -- there's too much variation among C library getopt()
889 implementations.
890
891- C++ compilers are better supported; the CXX macro is always set to a
892 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +0000893
Tim Petersd92dfe02000-12-12 01:18:41 +0000894Windows changes
895
896- select module: By default under Windows, a select() call
897 can specify no more than 64 sockets. Python now boosts
898 this Microsoft default to 512. If you need even more than
899 that, see the MS docs (you'll need to #define FD_SETSIZE
900 and recompile Python from source).
901
Guido van Rossumf61f1662001-01-10 20:13:55 +0000902- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
903 subdirectory is no more!
904
Tim Petersa3a3a032000-11-30 05:22:44 +0000905
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000906What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +0000907=========================
Guido van Rossum61000331997-08-15 04:39:58 +0000908
Guido van Rossum8ed602b2000-09-01 22:34:33 +0000909Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000910changes are in the file HISTORY. If you are making the jump directly
911from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
912HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +0000913
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000914Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
915the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
916http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +0000917
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000918--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +0000919
920======================================================================
921
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000922What's new in 2.0 (since release candidate 1)?
923==============================================
924
925Standard library
926
927- The copy_reg module was modified to clarify its intended use: to
928 register pickle support for extension types, not for classes.
929 pickle() will raise a TypeError if it is passed a class.
930
931- Fixed a bug in gettext's "normalize and expand" code that prevented
932 it from finding an existing .mo file.
933
934- Restored support for HTTP/0.9 servers in httplib.
935
Tim Peters989b7b92000-10-16 20:24:53 +0000936- The math module was changed to stop raising OverflowError in case of
937 underflow, and return 0 instead in underflow cases. Whether Python
938 used to raise OverflowError in case of underflow was platform-
939 dependent (it did when the platform math library set errno to ERANGE
940 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000941
942- Fixed a bug in StringIO that occurred when the file position was not
943 at the end of the file and write() was called with enough data to
944 extend past the end of the file.
945
946- Fixed a bug that caused Tkinter error messages to get lost on
947 Windows. The bug was fixed by replacing direct use of
948 interp->result with Tcl_GetStringResult(interp).
949
950- Fixed bug in urllib2 that caused it to fail when it received an HTTP
951 redirect response.
952
953- Several changes were made to distutils: Some debugging code was
954 removed from util. Fixed the installer used when an external zip
955 program (like WinZip) is not found; the source code for this
956 installer is in Misc/distutils. check_lib() was modified to behave
957 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
958 test for whether installed modules are on sys.path was changed to
959 use both normcase() and normpath().
960
Jeremy Hyltond867a2c2000-10-16 20:41:38 +0000961- Several minor bugs were fixed in the xml package (the minidom,
962 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000963
964- The regression test driver (regrtest.py) behavior when invoked with
965 -l changed: It now reports a count of objects that are recognized as
966 garbage but not freed by the garbage collector.
967
Tim Peters989b7b92000-10-16 20:24:53 +0000968- The regression test for the math module was changed to test
969 exceptional behavior when the test is run in verbose mode. Python
970 cannot yet guarantee consistent exception behavior across platforms,
971 so the exception part of test_math is run only in verbose mode, and
972 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000973
974Internals
975
976- PyOS_CheckStack() has been disabled on Win64, where it caused
977 test_sre to fail.
978
979Build issues
980
981- Changed compiler flags, so that gcc is always invoked with -Wall and
982 -Wstrict-prototypes. Users compiling Python with GCC should see
983 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +0000984 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +0000985 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000986
Tim Petersa3a3a032000-11-30 05:22:44 +0000987- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000988
989Tools and other miscellany
990
991- The compiler in Tools/compiler was updated to support the new
992 language features introduced in 2.0: extended print statement, list
993 comprehensions, and augmented assignments. The new compiler should
994 also be backwards compatible with Python 1.5.2; the compiler will
995 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +0000996 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000997
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000998What's new in 2.0 release candidate 1 (since beta 2)?
999=====================================================
1000
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001001What is release candidate 1?
1002
1003We believe that release candidate 1 will fix all known bugs that we
1004intend to fix for the 2.0 final release. This release should be a bit
1005more stable than the previous betas. We would like to see even more
1006widespread testing before the final release, so we are producing this
1007release candidate. The final release will be exactly the same unless
1008any show-stopping (or brown bag) bugs are found by testers of the
1009release candidate.
1010
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001011All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001012to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001013
1014Core language, builtins, and interpreter
1015
1016- A bug that caused crashes when __coerce__ was used with augmented
1017 assignment, e.g. +=, was fixed.
1018
1019- Raise ZeroDivisionError when raising zero to a negative number,
1020 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1021 power operator and the result of math.pow(0.0, -2.0) will vary by
1022 platform. On Linux, it raises a ValueError.
1023
1024- A bug in Unicode string interpolation was fixed that occasionally
1025 caused errors with formats including "%%". For example, the
1026 following expression "%% %s" % u"abc" no longer raises a TypeError.
1027
1028- Compilation of deeply nested expressions raises MemoryError instead
1029 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1030
1031- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1032 rendering them useless. They are now written in binary mode again.
1033
1034Standard library
1035
1036- Keyword arguments are now accepted for most pattern and match object
1037 methods in SRE, the standard regular expression engine.
1038
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001039- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001040 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001041
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001042- Several bugs in the Unicode handling and error handling in _tkinter
1043 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001044
1045- Fix memory management errors in Merge() and Tkapp_Call() routines.
1046
1047- Several changes were made to cStringIO to make it compatible with
1048 the file-like object interface and with StringIO. If operations are
1049 performed on a closed object, an exception is raised. The truncate
1050 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001051 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001052
1053- There were many changes made to the linuxaudiodev module and its
1054 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001055 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001056
1057 Note that this module is named poorly, because it should work
1058 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001059 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001060
1061 The module now raises exceptions when errors occur instead of
1062 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1063 audio) and defines a getptr() method that calls the
1064 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1065
1066- The library_version attribute, introduced in an earlier beta, was
1067 removed because it can not be supported with early versions of the C
1068 readline library, which provides no way to determine the version at
1069 compile-time.
1070
1071- The binascii module is now enabled on Win64.
1072
Tim Peters46446d62000-10-09 21:19:31 +00001073- tokenize.py no longer suffers "recursion depth" errors when parsing
1074 programs with very long string literals.
1075
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001076Internals
1077
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001078- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001079 which is called when the interpreter starts up to determine where
1080 the standard library is installed. These vulnerabilities affect all
1081 previous versions of Python and can be exploited by setting very
1082 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1083 setuid Python script, although use of the wrapper in
1084 Misc/setuid-prog.c will eliminate the vulnerability.
1085
1086- Fixed garbage collection bugs in instance creation that were
1087 triggered when errors occurred during initialization. The solution,
1088 applied in cPickle and in PyInstance_New(), is to call
1089 PyObject_GC_Init() after the initialization of the object's
1090 container attributes is complete.
1091
1092- pyexpat adds definitions of PyModule_AddStringConstant and
1093 PyModule_AddObject if the Python version is less than 2.0, which
1094 provides compatibility with PyXML on Python 1.5.2.
1095
1096- If the platform has a bogus definition for LONG_BIT (the number of
1097 bits in a long), an error will be reported at compile time.
1098
1099- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1100 collection crashes and possibly other, unreported crashes.
1101
1102- Fixed a memory leak in _PyUnicode_Fini().
1103
1104Build issues
1105
1106- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001107 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001108 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001109
1110- The mmap.PAGESIZE constant is now initialized using sysconf when
1111 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1112
1113- The md5 file should now compile on all platforms.
1114
1115- The select module now compiles on platforms that do not define
1116 POLLRDNORM and related constants.
1117
1118- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001119 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001120
Jeremy Hylton10921202000-10-09 18:34:12 +00001121- BeOS: A number of changes were made to the build and installation
1122 process. ar-fake now operates on a directory of object files.
1123 dl_export.h is gone, and its macros now appear on the mwcc command
1124 line during build on PPC BeOS.
1125
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001126- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001127 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001128
1129- Cygwin: Support for shared libraries, Tkinter, and sockets.
1130
1131- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1132
1133Tools and other miscellany
1134
1135- Removed debugging prints from main used with freeze.
1136
Tim Peters46446d62000-10-09 21:19:31 +00001137- IDLE auto-indent no longer crashes when it encounters Unicode
1138 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001139
1140What's new in 2.0 beta 2 (since beta 1)?
1141========================================
1142
1143Core language, builtins, and interpreter
1144
Tim Peters482c0212000-09-26 06:33:09 +00001145- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001146 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001147
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001148- Add -h and -V command line options to print the usage message and
1149 Python version number and exit immediately.
1150
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001151- eval() and exec accept Unicode objects as code parameters.
1152
1153- getattr() and setattr() now also accept Unicode objects for the
1154 attribute name, which are converted to strings using the default
1155 encoding before lookup.
1156
1157- Multiplication on string and Unicode now does proper bounds
1158 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1159 string is too long."
1160
1161- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001162 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001163
Jeremy Hylton1b618592000-09-26 05:32:36 +00001164
1165Standard library and extensions
1166
Guido van Rossum5b08f132001-04-16 02:05:23 +00001167- socket module: the OpenSSL code now adds support for RAND_status()
1168 and EGD (Entropy Gathering Device).
1169
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001170- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001171 argument checking; it still takes no arguments.
1172
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001173- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001174
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001175- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001176
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001177- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001178
1179- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001180 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001181
1182- copy: Copy Unicode objects atomically.
1183
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001184- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001185
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001186- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001187
Fred Drake67233bc2000-09-26 16:40:27 +00001188- dbm: Add get() and setdefault() methods to dbm object. Add constant
1189 `library' to module that names the library used. Added doc strings
1190 and method names to error messages. Uses configure to determine
1191 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
1192 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001193
1194- distutils: Update to version 0.9.3.
1195
1196- dl: Add several dl.RTLD_ constants.
1197
1198- fpectl: Now supported on FreeBSD.
1199
1200- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
1201 found by the collector will be saved in gc.garbage. This is useful
1202 for debugging a program that creates reference cycles.
1203
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001204- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00001205 of HTTP class. Do not close socket on zero-length response. Do not
1206 crash when server sends invalid content-length header.
1207
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001208- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001209
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001210- marshal: When reading a short, sign-extend on platforms where shorts
1211 are bigger than 16 bits. When reading a long, repair the unportable
1212 sign extension that was being done for 64-bit machines. (It assumed
1213 that signed right shift sign-extends.)
1214
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001215- operator: Add contains(), invert(), __invert__() as aliases for
1216 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001217
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001218- os: Add support for popen2() and popen3() on all platforms where
1219 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001220
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001221- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00001222 clicking on a file in Explorer (or passing the file name to the
1223 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001224
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001225- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00001226 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001227
1228- pickle: Now raises ValueError when an invalid pickle that contains
1229 a non-string repr where a string repr was expected. This behavior
1230 matches cPickle.
1231
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001232- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001233
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001234- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001235
1236- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001237 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001238 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001239
1240- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001241 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001242
1243- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00001244 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00001245 few cycles during startup since the first call to
1246 setdefaultencoding() will initialize the codec registry and the
1247 encodings package.
1248
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001249- socket: Support for size hint in readlines() method of object returned
1250 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001251
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001252- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001253 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001254 is followed by whitespace.
1255
Tim Petersa3a3a032000-11-30 05:22:44 +00001256- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001257
1258- struct: Check ranges for bytes and shorts.
1259
1260- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001261 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001262
1263- Tkinter: Image objects are now guaranteed to have unique ids. Set
1264 event.delta to zero if Tk version doesn't support mousewheel.
1265 Removed some debugging prints.
1266
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001267- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001268
Fred Drake67233bc2000-09-26 16:40:27 +00001269- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001270 which works around a bug in Norton AntiVirus 2000 that leads directly
1271 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001272
1273- xml: New version detection code allows PyXML to override standard
1274 XML package if PyXML version is greater than 0.6.1.
1275
Fred Drake64bb3802000-09-26 16:21:35 +00001276- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
1277 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
1278 tree only for nodes which are sufficiently interesting to a specific
1279 application. Does not provide the HTML-specific extensions. Still
1280 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001281
Fred Drake64bb3802000-09-26 16:21:35 +00001282- xml.sax: SAX 2 support for Python, including all the handler
1283 interfaces needed to process XML 1.0 compliant XML. Some
1284 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001285
Fred Drake64bb3802000-09-26 16:21:35 +00001286- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
1287 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001288
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001289
Jeremy Hylton1b618592000-09-26 05:32:36 +00001290C API
1291
1292- Add three new convenience functions for module initialization --
1293 PyModule_AddObject(), PyModule_AddIntConstant(), and
1294 PyModule_AddStringConstant().
1295
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001296- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00001297 removed and add #error to Python.h if NULL isn't defined after
1298 #include of stdio.h.
1299
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001300- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00001301 backwards compatibility (at the source level) with old extensions.
1302
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001303- A wrapper API was added for signal() and sigaction(). Instead of
1304 either function, always use PyOS_getsig() to get a signal handler
1305 and PyOS_setsig() to set one. A new convenience typedef
1306 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001307
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001308- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00001309 internal data buffer and size of a string object -- or the default
1310 encoded version of a Unicode object.
1311
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001312- PyString_Size() and PyString_AsString() accept Unicode objects.
1313
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001314- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00001315 exists). INT_MAX and LONG_MAX will always be defined, even if
1316 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001317
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001318- PyFloat_FromString takes a second argument, pend, that was
1319 effectively useless. It is now officially useless but preserved for
1320 backwards compatibility. If the pend argument is not NULL, *pend is
1321 set to NULL.
1322
1323- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
1324 for the attribute name. See note on getattr() above.
1325
1326- A few bug fixes to argument processing for Unicode.
1327 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
1328 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
1329 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00001330 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001331
1332- Py_BuildValue accepts B format (for bgen-generated code).
1333
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001334
Jeremy Hylton1b618592000-09-26 05:32:36 +00001335Internals
1336
1337- On Unix, fix code for finding Python installation directory so that
1338 it works when argv[0] is a relative path.
1339
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00001340- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001341 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00001342 rather than by generating a copy of the object.
1343
Tim Peters482c0212000-09-26 06:33:09 +00001344- Several of the internal Unicode tables are much smaller now, and
1345 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001346
Jeremy Hylton97693b02000-09-26 17:42:51 +00001347- In the garbage collector: Fixed bug in collection of tuples. Fixed
1348 bug that caused some instances to be removed from the container set
1349 while they were still live. Fixed parsing in gc.set_debug() for
1350 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001351
1352- Fixed refcount problem in instance deallocation that only occurred
1353 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
1354
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001355- On Windows, getpythonregpath is now protected against null data in
1356 registry key.
1357
1358- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00001359 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001360
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001361
Jeremy Hylton1b618592000-09-26 05:32:36 +00001362Build and platform-specific issues
1363
1364- Better support of GNU Pth via --with-pth configure option.
1365
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001366- Python/C API now properly exposed to dynamically-loaded extension
1367 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001368
1369- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
1370 Don't define MS_SYNC to be zero when it is undefined. Added missing
1371 prototypes in posixmodule.c.
1372
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001373- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001374 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001375
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001376- Fix largefile support on older NetBSD systems and OpenBSD by adding
1377 define for TELL64.
1378
1379
1380Tools and other miscellany
1381
1382- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
1383
1384- freeze: The modulefinder now works with 2.0 opcodes.
1385
Tim Petersa3a3a032000-11-30 05:22:44 +00001386- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001387 Move hackery of sys.argv until after the Tk instance has been
1388 created, which allows the application-specific Tkinter
1389 initialization to be executed if present; also pass an explicit
1390 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00001391
Jeremy Hylton1b618592000-09-26 05:32:36 +00001392
1393What's new in 2.0 beta 1?
1394=========================
1395
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001396Source Incompatibilities
1397------------------------
1398
1399None. Note that 1.6 introduced several incompatibilities with 1.5.2,
1400such as single-argument append(), connect() and bind(), and changes to
1401str(long) and repr(float).
1402
1403
1404Binary Incompatibilities
1405------------------------
1406
1407- Third party extensions built for Python 1.5.x or 1.6 cannot be used
1408with Python 2.0; these extensions will have to be rebuilt for Python
14092.0.
1410
1411- On Windows, attempting to import a third party extension built for
1412Python 1.5.x or 1.6 results in an immediate crash; there's not much we
1413can do about this. Check your PYTHONPATH environment variable!
1414
1415- Python bytecode files (*.pyc and *.pyo) are not compatible between
1416releases.
1417
1418
1419Overview of Changes Since 1.6
1420-----------------------------
1421
1422There are many new modules (including brand new XML support through
1423the xml package, and i18n support through the gettext module); a list
1424of all new modules is included below. Lots of bugs have been fixed.
1425
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001426The process for making major new changes to the language has changed
1427since Python 1.6. Enhancements must now be documented by a Python
1428Enhancement Proposal (PEP) before they can be accepted.
1429
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001430There are several important syntax enhancements, described in more
1431detail below:
1432
1433 - Augmented assignment, e.g. x += 1
1434
1435 - List comprehensions, e.g. [x**2 for x in range(10)]
1436
1437 - Extended import statement, e.g. import Module as Name
1438
1439 - Extended print statement, e.g. print >> file, "Hello"
1440
1441Other important changes:
1442
1443 - Optional collection of cyclical garbage
1444
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001445Python Enhancement Proposal (PEP)
1446---------------------------------
1447
1448PEP stands for Python Enhancement Proposal. A PEP is a design
1449document providing information to the Python community, or describing
1450a new feature for Python. The PEP should provide a concise technical
1451specification of the feature and a rationale for the feature.
1452
1453We intend PEPs to be the primary mechanisms for proposing new
1454features, for collecting community input on an issue, and for
1455documenting the design decisions that have gone into Python. The PEP
1456author is responsible for building consensus within the community and
1457documenting dissenting opinions.
1458
1459The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001460
1461Augmented Assignment
1462--------------------
1463
1464This must have been the most-requested feature of the past years!
1465Eleven new assignment operators were added:
1466
Guido van Rossume905e952000-09-05 12:42:46 +00001467 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001468
1469For example,
1470
1471 A += B
1472
1473is similar to
1474
1475 A = A + B
1476
1477except that A is evaluated only once (relevant when A is something
1478like dict[index].attr).
1479
1480However, if A is a mutable object, A may be modified in place. Thus,
1481if A is a number or a string, A += B has the same effect as A = A+B
1482(except A is only evaluated once); but if a is a list, A += B has the
1483same effect as A.extend(B)!
1484
1485Classes and built-in object types can override the new operators in
1486order to implement the in-place behavior; the not-in-place behavior is
1487used automatically as a fallback when an object doesn't implement the
1488in-place behavior. For classes, the method name is derived from the
1489method name for the corresponding not-in-place operator by inserting
1490an 'i' in front of the name, e.g. __iadd__ implements in-place
1491__add__.
1492
1493Augmented assignment was implemented by Thomas Wouters.
1494
1495
1496List Comprehensions
1497-------------------
1498
1499This is a flexible new notation for lists whose elements are computed
1500from another list (or lists). The simplest form is:
1501
1502 [<expression> for <variable> in <sequence>]
1503
Guido van Rossum56db0952000-09-06 23:34:25 +00001504For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001505This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001506
1507You can also add a condition:
1508
1509 [<expression> for <variable> in <sequence> if <condition>]
1510
1511For example, [w for w in words if w == w.lower()] would yield the list
1512of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001513than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001514
1515You can also have nested for loops and more than one 'if' clause. For
1516example, here's a function that flattens a sequence of sequences::
1517
1518 def flatten(seq):
1519 return [x for subseq in seq for x in subseq]
1520
1521 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
1522
1523This prints
1524
1525 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
1526
1527List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001528Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001529
1530
1531Extended Import Statement
1532-------------------------
1533
1534Many people have asked for a way to import a module under a different
1535name. This can be accomplished like this:
1536
1537 import foo
1538 bar = foo
1539 del foo
1540
1541but this common idiom gets old quickly. A simple extension of the
1542import statement now allows this to be written as follows:
1543
1544 import foo as bar
1545
1546There's also a variant for 'from ... import':
1547
1548 from foo import bar as spam
1549
1550This also works with packages; e.g. you can write this:
1551
1552 import test.regrtest as regrtest
1553
1554Note that 'as' is not a new keyword -- it is recognized only in this
1555context (this is only possible because the syntax for the import
1556statement doesn't involve expressions).
1557
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001558Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001559
1560
1561Extended Print Statement
1562------------------------
1563
1564Easily the most controversial new feature, this extension to the print
1565statement adds an option to make the output go to a different file
1566than the default sys.stdout.
1567
1568For example, to write an error message to sys.stderr, you can now
1569write:
1570
1571 print >> sys.stderr, "Error: bad dog!"
1572
1573As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00001574evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001575
1576 print >> None, "Hello world"
1577
1578is equivalent to
1579
1580 print "Hello world"
1581
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001582Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001583
1584
1585Optional Collection of Cyclical Garbage
1586---------------------------------------
1587
1588Python is now equipped with a garbage collector that can hunt down
1589cyclical references between Python objects. It's no replacement for
1590reference counting; in fact, it depends on the reference counts being
1591correct, and decides that a set of objects belong to a cycle if all
1592their reference counts can be accounted for from their references to
1593each other. This devious scheme was first proposed by Eric Tiedemann,
1594and brought to implementation by Neil Schemenauer.
1595
1596There's a module "gc" that lets you control some parameters of the
1597garbage collection. There's also an option to the configure script
1598that lets you enable or disable the garbage collection. In 2.0b1,
1599it's on by default, so that we (hopefully) can collect decent user
1600experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00001601performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001602off by default in the final 2.0 release.
1603
1604
1605Smaller Changes
1606---------------
1607
1608A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
1609map(None, seq1, seq2, ...) when the sequences have the same length;
1610i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
1611the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001612zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001613
1614sys.version_info is a tuple (major, minor, micro, level, serial).
1615
1616Dictionaries have an odd new method, setdefault(key, default).
1617dict.setdefault(key, default) returns dict[key] if it exists; if not,
1618it sets dict[key] to default and returns that value. Thus:
1619
1620 dict.setdefault(key, []).append(item)
1621
1622does the same work as this common idiom:
1623
1624 if not dict.has_key(key):
1625 dict[key] = []
1626 dict[key].append(item)
1627
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001628There are two new variants of SyntaxError that are raised for
1629indentation-related errors: IndentationError and TabError.
1630
1631Changed \x to consume exactly two hex digits; see PEP 223. Added \U
1632escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001633
1634The limits on the size of expressions and file in Python source code
1635have been raised from 2**16 to 2**32. Previous versions of Python
1636were limited because the maximum argument size the Python VM accepted
1637was 2**16. This limited the size of object constructor expressions,
1638e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
1639limit was raised thanks to a patch by Charles Waldman that effectively
1640fixes the problem. It is now much more likely that you will be
1641limited by available memory than by an arbitrary limit in Python.
1642
1643The interpreter's maximum recursion depth can be modified by Python
1644programs using sys.getrecursionlimit and sys.setrecursionlimit. This
1645limit is the maximum number of recursive calls that can be made by
1646Python code. The limit exists to prevent infinite recursion from
1647overflowing the C stack and causing a core dump. The default value is
16481000. The maximum safe value for a particular platform can be found
1649by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001650
1651New Modules and Packages
1652------------------------
1653
1654atexit - for registering functions to be called when Python exits.
1655
1656imputil - Greg Stein's alternative API for writing custom import
1657hooks.
1658
1659pyexpat - an interface to the Expat XML parser, contributed by Paul
1660Prescod.
1661
1662xml - a new package with XML support code organized (so far) in three
1663subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
1664would fill a volume. There's a special feature whereby a
1665user-installed package named _xmlplus overrides the standard
1666xmlpackage; this is intended to give the XML SIG a hook to distribute
1667backwards-compatible updates to the standard xml package.
1668
1669webbrowser - a platform-independent API to launch a web browser.
1670
1671
Guido van Rossume905e952000-09-05 12:42:46 +00001672Changed Modules
1673---------------
1674
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001675array -- new methods for array objects: count, extend, index, pop, and
1676remove
1677
1678binascii -- new functions b2a_hex and a2b_hex that convert between
1679binary data and its hex representation
1680
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001681calendar -- Many new functions that support features including control
1682over which day of the week is the first day, returning strings instead
1683of printing them. Also new symbolic constants for days of week,
1684e.g. MONDAY, ..., SUNDAY.
1685
1686cgi -- FieldStorage objects have a getvalue method that works like a
1687dictionary's get method and returns the value attribute of the object.
1688
1689ConfigParser -- The parser object has new methods has_option,
1690remove_section, remove_option, set, and write. They allow the module
1691to be used for writing config files as well as reading them.
1692
1693ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00001694optionally support the RFC 959 REST command.
1695
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001696gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00001697
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001698httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
1699the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00001700
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001701locale -- implement getdefaultlocale for Win32 and Macintosh
1702
1703marshal -- no longer dumps core when marshaling deeply nested or
1704recursive data structures
1705
1706os -- new functions isatty, seteuid, setegid, setreuid, setregid
1707
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001708os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
1709support under Unix.
1710
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001711os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001712
1713os.path -- fix semantics of os.path.commonprefix
1714
1715smtplib -- support for sending very long messages
1716
1717socket -- new function getfqdn()
1718
1719readline -- new functions to read, write and truncate history files.
1720The readline section of the library reference manual contains an
1721example.
1722
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001723select -- add interface to poll system call
1724
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001725shutil -- new copyfileobj function
1726
1727SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
1728HTTP server.
1729
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001730Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001731
1732urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00001733e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001734
1735whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00001736
1737
1738Obsolete Modules
1739----------------
1740
1741None. However note that 1.6 made a whole slew of modules obsolete:
1742stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
1743poly, zmod, strop, util, whatsound.
1744
1745
1746Changed, New, Obsolete Tools
1747----------------------------
1748
Tim Peters8b092332000-09-05 20:15:25 +00001749None.
Guido van Rossume905e952000-09-05 12:42:46 +00001750
1751
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001752C-level Changes
1753---------------
1754
1755Several cleanup jobs were carried out throughout the source code.
1756
1757All C code was converted to ANSI C; we got rid of all uses of the
1758Py_PROTO() macro, which makes the header files a lot more readable.
1759
1760Most of the portability hacks were moved to a new header file,
1761pyport.h; several other new header files were added and some old
1762header files were removed, in an attempt to create a more rational set
1763of header files. (Few of these ever need to be included explicitly;
1764they are all included by Python.h.)
1765
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001766Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001767and Win64, especially for the new Intel Itanium processor. Mick also
1768added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001769
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001770The C APIs to return an object's size have been update to consistently
1771use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
1772previous versions, the abstract interfaces used PyXXX_Length and the
1773concrete interfaces used PyXXX_Size. The old names,
1774e.g. PyObject_Length, are still available for backwards compatibility
1775at the API level, but are deprecated.
1776
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001777The PyOS_CheckStack function has been implemented on Windows by
1778Fredrik Lundh. It prevents Python from failing with a stack overflow
1779on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001780
1781The GC changes resulted in creation of two new slots on object,
1782tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00001783the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001784
1785The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00001786C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001787
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001788PyErr_Format has been updated to automatically calculate the size of
1789the buffer needed to hold the formatted result string. This change
1790prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001791
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001792New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00001793
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001794PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
1795that are the same as their non-Ex counterparts except they take an
1796extra flag argument that tells them to close the file when done.
1797
1798XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00001799
Tim Peters8b092332000-09-05 20:15:25 +00001800
1801Windows Changes
1802---------------
1803
1804New popen2/popen3/peopen4 in os module (see Changed Modules above).
1805
1806os.popen is much more usable on Windows 95 and 98. See Microsoft
1807Knowledge Base article Q150956. The Win9x workaround described there
1808is implemented by the new w9xpopen.exe helper in the root of your
1809Python installation. Note that Python uses this internally; it is not
1810a standalone program.
1811
1812Administrator privileges are no longer required to install Python
1813on Windows NT or Windows 2000. If you have administrator privileges,
1814Python's registry info will be written under HKEY_LOCAL_MACHINE.
1815Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00001816under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00001817uses of Python, but will prevent some advanced uses from working
1818(for example, running a Python script as an NT service, or possibly
1819from CGI).
1820
1821[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
1822installer; instead, it installs the needed Tcl/Tk files directly in the
1823Python directory. If you already have a Tcl/Tk installation, this
1824wastes some disk space (about 4 Megs) but avoids problems with
1825conflicting Tcl/Tk installations, and makes it much easier for Python
1826to ensure that Tcl/Tk can find all its files.
1827
1828[This was new in 1.6] The Windows installer now installs by default in
1829\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
1830
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001831
1832Updates to the changes between 1.5.2 and 1.6
1833--------------------------------------------
1834
1835The 1.6 NEWS file can't be changed after the release is done, so here
1836is some late-breaking news:
1837
1838New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
1839and changes to getlocale() and setlocale().
1840
1841The new module is now enabled per default.
1842
1843It is not true that the encodings codecs cannot be used for normal
1844strings: the string.encode() (which is also present on 8-bit strings
1845!) allows using them for 8-bit strings too, e.g. to convert files from
1846cp1252 (Windows) to latin-1 or vice-versa.
1847
1848Japanese codecs are available from Tamito KAJIYAMA:
1849http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
1850
1851
Guido van Rossumab9d6f01998-08-10 22:01:13 +00001852======================================================================