blob: bce388928316326a713c394341860d82b9c53e01 [file] [log] [blame]
Tim Petersf553f892001-05-01 20:45:31 +00001What's New in Python 2.2a0?
2===========================
3
4Core
5
6- The following functions were generalized to work nicely with iterator
7 arguments:
8 list()
9
10
Guido van Rossumffe13be2001-04-16 18:46:45 +000011What's New in Python 2.1 (final)?
12=================================
13
14We only changed a few things since the last release candidate, all in
15Python library code:
16
17- A bug in the locale module was fixed that affected locales which
18 define no grouping for numeric formatting.
19
20- A few bugs in the weakref module's implementations of weak
21 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
22 and the test suite was updated to check for these bugs.
23
24- An old bug in the os.path.walk() function (introduced in Python
25 2.0!) was fixed: a non-existent file would cause an exception
26 instead of being ignored.
27
28- Fixed a few bugs in the new symtable module found by Neil Norwitz's
29 PyChecker.
30
31
Guido van Rossum5b08f132001-04-16 02:05:23 +000032What's New in Python 2.1c2?
33===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +000034
Guido van Rossum5b08f132001-04-16 02:05:23 +000035A flurry of small changes, and one showstopper fixed in the nick of
36time made it necessary to release another release candidate. The list
37here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +000038
Guido van Rossum5b08f132001-04-16 02:05:23 +000039Core
Guido van Rossum4fb60362001-04-13 00:46:14 +000040
Guido van Rossum5b08f132001-04-16 02:05:23 +000041- Tim discovered a nasty bug in the dictionary code, caused by
42 PyDict_Next() calling dict_resize(), and the GC code's use of
43 PyDict_Next() violating an assumption in dict_items(). This was
44 fixed with considerable amounts of band-aid, but the net effect is a
45 saner and more robust implementation.
46
47- Made a bunch of symbols static that were accidentally global.
48
49Build and Ports
50
51- The setup.py script didn't check for a new enough version of zlib
52 (1.1.3 is needed). Now it does.
53
54- Changed "make clean" target to also remove shared libraries.
55
56- Added a more general warning about the SGI Irix optimizer to README.
57
58Library
59
60- Fix a bug in urllib.basejoin("http://host", "../file.html") which
61 omitted the slash between host and file.html.
62
63- The mailbox module's _Mailbox class contained a completely broken
64 and undocumented seek() method. Ripped it out.
65
66- Fixed a bunch of typos in various library modules (urllib2, smtpd,
67 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
68
69- Fixed a few last-minute bugs in unittest.
70
71Extensions
72
73- Reverted the patch to the OpenSSL code in socketmodule.c to support
74 RAND_status() and the EGD, and the subsequent patch that tried to
75 fix it for pre-0.9.5 versions; the problem with the patch is that on
76 some systems it issues a warning whenever socket is imported, and
77 that's unacceptable.
78
79Tests
80
81- Fixed the pickle tests to work with "import test.test_pickle".
82
83- Tweaked test_locale.py to actually run the test Windows.
84
85- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
86 not "wb" (which is not a valid mode at all).
87
88- Fix pstats browser crashes. Import readline if it exists to make
89 the user interface nicer.
90
91- Add "import thread" to the top of test modules that import the
92 threading module (test_asynchat and test_threadedtempfile). This
93 prevents test failures caused by a broken threading module resulting
94 from a previously caught failed import.
95
96- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
97 needed on some platforms (e.g. Solaris 8) when the tests are run
98 twice in succession.
99
100- Skip rather than fail test_sunaudiodev if no audio device is found.
101
102
103What's New in Python 2.1c1?
104===========================
105
106This list was significantly updated when 2.1c2 was released; the 2.1c1
107release didn't mention most changes that were actually part of 2.1c1:
108
109Legal
110
111- Copyright was assigned to the Python Software Foundation (PSF) and a
112 PSF license (very similar to the CNRI license) was added.
113
114- The CNRI copyright notice was updated to include 2001.
115
116Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000117
Guido van Rossumc9932722001-04-12 02:31:27 +0000118- After a public outcry, assignment to __debug__ is no longer illegal;
119 instead, a warning is issued. It will become illegal in 2.2.
120
Guido van Rossum5b08f132001-04-16 02:05:23 +0000121- Fixed a core dump with "%#x" % 0, and changed the semantics so that
122 "%#x" now always prepends "0x", even if the value is zero.
123
124- Fixed some nits in the bytecode compiler.
125
126- Fixed core dumps when calling certain kinds of non-functions.
127
128- Fixed various core dumps caused by reference count bugs.
129
130Build and Ports
131
132- Use INSTALL_SCRIPT to install script files.
133
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000134- New port: SCO Unixware 7, by Billy G. Allie.
135
Guido van Rossum5b08f132001-04-16 02:05:23 +0000136- Updated RISCOS port.
137
138- Updated BeOS port and notes.
139
140- Various other porting problems resolved.
141
142Library
143
144- The TERMIOS and SOCKET modules are now truly obsolete and
145 unnecessary. Their symbols are incorporated in the termios and
146 socket modules.
147
148- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
149 better tests for pickling.
150
151- threading: make Condition.wait() robust against KeyboardInterrupt.
152
153- zipfile: add support to zipfile to support opening an archive
154 represented by an open file rather than a file name. Fix bug where
155 the archive was not properly closed. Fixed a bug in this bugfix
156 where flush() was called for a read-only file.
157
158- imputil: added an uninstall() method to the ImportManager.
159
160- Canvas: fixed bugs in lower() and tkraise() methods.
161
162- SocketServer: API change (added overridable close_request() method)
163 so that the TCP server can explicitly close the request.
164
165- pstats: Eric Raymond added a simple interactive statistics browser,
166 invoked when the module is run as a script.
167
168- locale: fixed a problem in format().
169
170- webbrowser: made it work when the BROWSER environment variable has a
171 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
172 KDE 2. Fixed some other nits.
173
174- unittest: changes to allow using a different exception than
175 AssertionError, and added a few more function aliases. Some other
176 small changes.
177
178- urllib, urllib2: fixed redirect problems and a coupleof other nits.
179
180- asynchat: fixed a critical bug in asynchat that slipped through the
181 2.1b2 release. Fixed another rare bug.
182
183- Fix some unqualified except: clauses (always a bad code example).
184
185XML
186
187- pyexpat: new API get_version_string().
188
189- Fixed some minidom bugs.
190
191Extensions
192
193- Fixed a core dump in _weakref. Removed the weakref.mapping()
194 function (it adds nothing to the API).
195
196- Rationalized the use of header files in the readline module, to make
197 it compile (albeit with some warnings) with the very recent readline
198 4.2, without breaking for earlier versions.
199
200- Hopefully fixed a buffering problem in linuxaudiodev.
201
202- Attempted a fix to make the OpenSSL support in the socket module
203 work again with pre-0.9.5 versions of OpenSSL.
204
205Tests
206
207- Added a test case for asynchat and asyncore.
208
209- Removed coupling between tests where one test failing could break
210 another.
211
212Tools
213
214- Ping added an interactive help browser to pydoc, fixed some nits
215 in the rest of the pydoc code, and added some features to his
216 inspect module.
217
218- An updated python-mode.el version 4.1 which integrates Ken
219 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
220 much nicer in XEmacs and Emacs. When stepping through your program
221 with pdb, in either the shell window or the *Python* window, the
222 source file and line will be tracked by an arrow. Very cool!
223
224- IDLE: syntax warnings in interactive mode are changed into errors.
225
226- Some improvements to Tools/webchecker (ignore some more URL types,
227 follow some more links).
228
229- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000230
Barry Warsaw11e89c72001-04-11 20:37:57 +0000231
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000232What's New in Python 2.1 beta 2?
233================================
234
Guido van Rossum053ae352001-03-22 14:17:21 +0000235(Unlisted are many fixed bugs, more documentation, etc.)
236
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000237Core language, builtins, and interpreter
238
Guido van Rossum053ae352001-03-22 14:17:21 +0000239- The nested scopes work (enabled by "from __future__ import
240 nested_scopes") is completed; in particular, the future now extends
241 into code executed through exec, eval() and execfile(), and into the
242 interactive interpreter.
243
244- When calling a base class method (e.g. BaseClass.__init__(self)),
245 this is now allowed even if self is not strictly spoken a class
246 instance (e.g. when using metaclasses or the Don Beaudry hook).
247
248- Slice objects are now comparable but not hashable; this prevents
249 dict[:] from being accepted but meaningless.
250
251- Complex division is now calculated using less braindead algorithms.
252 This doesn't change semantics except it's more likely to give useful
253 results in extreme cases. Complex repr() now uses full precision
254 like float repr().
255
256- sgmllib.py now calls handle_decl() for simple <!...> declarations.
257
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000258- It is illegal to assign to the name __debug__, which is set when the
259 interpreter starts. It is effectively a compile-time constant.
260
261- A warning will be issued if a global statement for a variable
262 follows a use or assignment of that variable.
263
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000264Standard library
265
Guido van Rossum053ae352001-03-22 14:17:21 +0000266- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
267 inspired by JUnit), is now part of the standard library. You now
268 have a choice of two testing frameworks: unittest requires you to
269 write testcases as separate code, doctest gathers them from
270 docstrings. Both approaches have their advantages and
271 disadvantages.
272
273- A new module Tix was added, which wraps the Tix extension library
274 for Tk. With that module, it is not necessary to statically link
275 Tix with _tkinter, since Tix will be loaded with Tcl's "package
276 require" command. See Demo/tix/.
277
278- tzparse.py is now obsolete.
279
280- In gzip.py, the seek() and tell() methods are removed -- they were
281 non-functional anyway, and it's better if callers can test for their
282 existence with hasattr().
283
284Python/C API
285
286- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
287 that's already in the dictionary during a PyDict_Next() iteration.
288 This used to fail occasionally when a dictionary resize operation
289 could be triggered that would rehash all the keys. All other
290 modifications to the dictionary are still off-limits during a
291 PyDict_Next() iteration!
292
293- New extended APIs related to passing compiler variables around.
294
295- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
296 implement isinstance() and issubclass().
297
298- Py_BuildValue() now has a "D" conversion to create a Python complex
299 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000300
Fred Drake4e262a92001-03-22 18:26:47 +0000301- Extensions types which support weak references must now set the
302 field allocated for the weak reference machinery to NULL themselves;
303 this is done to avoid the cost of checking each object for having a
304 weakly referencable type in PyObject_INIT(), since most types are
305 not weakly referencable.
306
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000307- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
308 free variables and cell variables to and from the frame's f_locals.
309
310- Variants of several functions defined in pythonrun.h have been added
311 to support the nested_scopes future statement. The variants all end
312 in Flags and take an extra argument, a PyCompilerFlags *; examples:
313 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
314 variants may be removed in Python 2.2, when nested scopes are
315 mandatory.
316
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000317Distutils
318
319- the sdist command now writes a PKG-INFO file, as described in PEP 241,
320 into the release tree.
321
322- several enhancements to the bdist_wininst command from Thomas Heller
323 (an uninstaller, more customization of the installer's display)
324
325- from Jack Jansen: added Mac-specific code to generate a dialog for
326 users to specify the command-line (because providing a command-line with
327 MacPython is awkward). Jack also made various fixes for the Mac
328 and the Metrowerks compiler.
329
330- added 'platforms' and 'keywords' to the set of metadata that can be
Andrew M. Kuchling68ad64a2001-03-31 02:42:42 +0000331 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000332
333- applied patches from Jason Tishler to make the compiler class work with
334 Cygwin.
335
336
Tim Peters2fe289a2001-03-01 22:19:38 +0000337What's New in Python 2.1 beta 1?
338================================
Tim Petersd66595f2001-02-04 03:09:53 +0000339
340Core language, builtins, and interpreter
341
Guido van Rossum9d0fbde2001-03-02 14:00:32 +0000342- Following an outcry from the community about the amount of code
343 broken by the nested scopes feature introduced in 2.1a2, we decided
344 to make this feature optional, and to wait until Python 2.2 (or at
345 least 6 months) to make it standard. The option can be enabled on a
346 per-module basis by adding "from __future__ import nested_scopes" at
347 the beginning of a module (before any other statements, but after
348 comments and an optional docstring). See PEP 236 (Back to the
349 __future__) for a description of the __future__ statement. PEP 227
350 (Statically Nested Scopes) has been updated to reflect this change,
351 and to clarify the semantics in a number of endcases.
352
353- The nested scopes code, when enabled, has been hardened, and most
354 bugs and memory leaks in it have been fixed.
355
356- Compile-time warnings are now generated for a number of conditions
357 that will break or change in meaning when nested scopes are enabled:
358
359 - Using "from...import *" or "exec" without in-clause in a function
360 scope that also defines a lambda or nested function with one or
361 more free (non-local) variables. The presence of the import* or
362 bare exec makes it impossible for the compiler to determine the
363 exact set of local variables in the outer scope, which makes it
364 impossible to determine the bindings for free variables in the
365 inner scope. To avoid the warning about import *, change it into
366 an import of explicitly name object, or move the import* statement
367 to the global scope; to avoid the warning about bare exec, use
368 exec...in... (a good idea anyway -- there's a possibility that
369 bare exec will be deprecated in the future).
370
371 - Use of a global variable in a nested scope with the same name as a
372 local variable in a surrounding scope. This will change in
373 meaning with nested scopes: the name in the inner scope will
374 reference the variable in the outer scope rather than the global
375 of the same name. To avoid the warning, either rename the outer
376 variable, or use a global statement in the inner function.
377
Neil Schemenauera35c6882001-02-27 04:45:05 +0000378- An optional object allocator has been included. This allocator is
379 optimized for Python objects and should be faster and use less memory
380 than the standard system allocator. It is not enabled by default
381 because of possible thread safety problems. The allocator is only
382 protected by the Python interpreter lock and it is possible that some
383 extension modules require a thread safe allocator. The object
384 allocator can be enabled by providing the "--with-pymalloc" option to
385 configure.
386
Tim Petersd66595f2001-02-04 03:09:53 +0000387Standard library
388
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000389- pyexpat now detects the expat version if expat.h defines it. A
390 number of additional handlers are provided, which are only available
391 since expat 1.95. In addition, the methods SetParamEntityParsing and
392 GetInputContext of Parser objects are available with 1.95.x
393 only. Parser objects now provide the ordered_attributes and
394 specified_attributes attributes. A new module expat.model was added,
395 which offers a number of additional constants if 1.95.x is used.
396
397- xml.dom offers the new functions registerDOMImplementation and
398 getDOMImplementation.
399
400- xml.dom.minidom offers a toprettyxml method. A number of DOM
401 conformance issues have been resolved. In particular, Element now
402 has an hasAttributes method, and the handling of namespaces was
403 improved.
404
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000405- Ka-Ping Yee contributed two new modules: inspect.py, a module for
406 getting information about live Python code, and pydoc.py, a module
407 for interactively converting docstrings to HTML or text.
408 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +0000409 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +0000410 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
411 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000412
Tim Peters1eff7962001-03-01 02:31:33 +0000413- New library module difflib.py, primarily packaging the SequenceMatcher
414 class at the heart of the popular ndiff.py file-comparison tool.
415
416- doctest.py (a framework for verifying Python code examples in docstrings)
417 is now part of the std library.
418
Tim Petersd66595f2001-02-04 03:09:53 +0000419Windows changes
420
Guido van Rossume3955a82001-03-02 14:05:59 +0000421- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
422 small GUI that lets you browse the module docstrings using your
423 default web browser.
424
Tim Peters1eff7962001-03-01 02:31:33 +0000425- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
426 Platforms) is implemented. See
427
428 http://python.sourceforge.net/peps/pep-0235.html
429
430 for full details, especially the "Current Lower-Left Semantics" section.
431 The new Windows import rules are simpler than before:
432
433 A. If the PYTHONCASEOK environment variable exists, same as
434 before: silently accept the first case-insensitive match of any
435 kind; raise ImportError if none found.
436
437 B. Else search sys.path for the first case-sensitive match; raise
438 ImportError if none found.
439
440 The same rules have been implented on other platforms with case-
441 insensitive but case-preserving filesystems too (including Cygwin, and
442 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +0000443
Tim Peters25a9ce32001-02-19 07:06:36 +0000444- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
445 what it's supposed to do (and does do under NT and 2000) via direct
446 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +0000447 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +0000448 all Win9x systems before.
449
Tim Peters1eff7962001-03-01 02:31:33 +0000450- Build: Subproject _test (effectively) renamed to _testcapi.
451
Tim Peters2fe289a2001-03-01 22:19:38 +0000452New platforms
453
454- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
455 Thanks to Steven Majewski!
456
457- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
458 Tishler!
459
Guido van Rossum9089b272001-03-02 06:49:50 +0000460- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
461 Schwertberger! See RISCOS/README for more information -- it seems
462 that because of the bizarre filename conventions on RISCOS, no port
463 to that platform is easy. Note that the new variable os.endsep is
464 silently supported in order to make life easier on this platform,
465 but we don't advertise it because it's not worth for most folks to
466 care about RISCOS portability.
467
Tim Peters25a9ce32001-02-19 07:06:36 +0000468
Tim Petersd7b5e882001-01-25 03:36:26 +0000469What's New in Python 2.1 alpha 2?
470=================================
Tim Peters40ead762001-01-27 05:35:26 +0000471
Tim Petersd7b5e882001-01-25 03:36:26 +0000472Core language, builtins, and interpreter
473
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000474- Scopes nest. If a name is used in a function or class, but is not
475 local, the definition in the nearest enclosing function scope will
476 be used. One consequence of this change is that lambda statements
477 could reference variables in the namespaces where the lambda is
478 defined. In some unusual cases, this change will break code.
479
480 In all previous version of Python, names were resolved in exactly
481 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000482 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000483 function A is defined within a function B, the names bound in B are
484 not visible in A. The new rules make names bound in B visible in A,
485 unless A contains a name binding that hides the binding in B.
486
487 Section 4.1 of the reference manual describes the new scoping rules
488 in detail. The test script in Lib/test/test_scope.py demonstrates
489 some of the effects of the change.
490
491 The new rules will cause existing code to break if it defines nested
492 functions where an outer function has local variables with the same
493 name as globals or builtins used by the inner function. Example:
494
495 def munge(str):
496 def helper(x):
497 return str(x)
498 if type(str) != type(''):
499 str = helper(str)
500 return str.strip()
501
502 Under the old rules, the name str in helper() is bound to the
503 builtin function str(). Under the new rules, it will be bound to
504 the argument named str and an error will occur when helper() is
505 called.
506
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000507- The compiler will report a SyntaxError if "from ... import *" occurs
508 in a function or class scope. The language reference has documented
509 that this case is illegal, but the compiler never checked for it.
510 The recent introduction of nested scope makes the meaning of this
511 form of name binding ambiguous. In a future release, the compiler
512 may allow this form when there is no possibility of ambiguity.
513
Tim Peters40ead762001-01-27 05:35:26 +0000514- repr(string) is easier to read, now using hex escapes instead of octal,
515 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
516
517 >>> "\texample \r\n" + chr(0) + chr(255)
518 '\texample \r\n\x00\xff' # in 2.1
519 '\011example \015\012\000\377' # in 2.0
520
Moshe Zadka6af0ce02001-01-29 06:41:00 +0000521- Functions are now compared and hashed by identity, not by value, since
522 the func_code attribute is writable.
523
Fred Drakefb9d7122001-02-01 20:00:40 +0000524- Weak references (PEP 205) have been added. This involves a few
525 changes in the core, an extension module (_weakref), and a Python
526 module (weakref). The weakref module is the public interface. It
527 includes support for "explicit" weak references, proxy objects, and
528 mappings with weakly held values.
529
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000530- A 'continue' statement can now appear in a try block within the body
531 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +0000532 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000533
Tim Petersd7b5e882001-01-25 03:36:26 +0000534Standard library
535
Barry Warsaw30dbd142001-01-31 22:14:01 +0000536- mailbox.py now has a new class, PortableUnixMailbox which is
537 identical to UnixMailbox but uses a more portable scheme for
538 determining From_ separators. Also, the constructors for all the
539 classes in this module have a new optional `factory' argument, which
540 is a callable used when new message classes must be instantiated by
541 the next() method.
542
Tim Petersd7b5e882001-01-25 03:36:26 +0000543- random.py is now self-contained, and offers all the functionality of
544 the now-deprecated whrandom.py. See the docs for details. random.py
545 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +0000546 and restoring the internal state of the generator; and jumpahead(n),
547 for quickly forcing the internal state to be the same as if n calls to
548 random() had been made. The latter is particularly useful for multi-
549 threaded programs, creating one instance of the random.Random() class for
550 each thread, then using .jumpahead() to force each instance to use a
551 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +0000552
Tim Peters0de88fc2001-02-01 04:59:18 +0000553- random.py's seed() function is new. For bit-for-bit compatibility with
554 prior releases, use the whseed function instead. The new seed function
555 addresses two problems: (1) The old function couldn't produce more than
556 about 2**24 distinct internal states; the new one about 2**45 (the best
557 that can be done in the Wichmann-Hill generator). (2) The old function
558 sometimes produced identical internal states when passed distinct
559 integers, and there was no simple way to predict when that would happen;
560 the new one guarantees to produce distinct internal states for all
561 arguments in [0, 27814431486576L).
562
Jeremy Hylton4c4fda02001-02-02 03:29:24 +0000563- The socket module now supports raw packets on Linux. The socket
564 family is AF_PACKET.
565
Tim Peters9ea17ac2001-02-02 05:57:15 +0000566- test_capi.py is a start at running tests of the Python C API. The tests
567 are implemented by the new Modules/_testmodule.c.
568
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000569- A new extension module, _symtable, provides provisional access to the
570 internal symbol table used by the Python compiler. A higher-level
571 interface will be added on top of _symtable in a future release.
572
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +0000573- Removed the obsolete soundex module.
574
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000575- xml.dom.minidom now uses the standard DOM exceptions. Node supports
576 the isSameNode method; NamedNodeMap the get method.
577
578- xml.sax.expatreader supports the lexical handler property; it
579 generates comment, startCDATA, and endCDATA events.
580
Tim Petersee826f82001-01-31 19:39:44 +0000581Windows changes
582
583- Build procedure: the zlib project is built in a different way that
584 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +0000585 the zlib binary used. See PCbuild\readme.txt for details. Your old
586 zlib-related directories can be deleted; you'll need to download fresh
587 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +0000588
Tim Peters9ea17ac2001-02-02 05:57:15 +0000589- Build: New subproject _test for the benefit of test_capi.py (see above).
590
Tim Petersb16c56f2001-02-02 21:24:51 +0000591- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
592 interface to some Python compiler internals).
593
594- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +0000595 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +0000596
Tim Petersa3a3a032000-11-30 05:22:44 +0000597What's New in Python 2.1 alpha 1?
598=================================
599
600Core language, builtins, and interpreter
601
Marc-André Lemburgebb195b2001-01-20 10:34:52 +0000602- There is a new Unicode companion to the PyObject_Str() API
603 called PyObject_Unicode(). It behaves in the same way as the
604 former, but assures that the returned value is an Unicode object
605 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +0000606
Guido van Rossumf98eda02001-01-17 15:54:45 +0000607- The comparison operators support "rich comparison overloading" (PEP
608 207). C extension types can provide a rich comparison function in
609 the new tp_richcompare slot in the type object. The cmp() function
610 and the C function PyObject_Compare() first try the new rich
611 comparison operators before trying the old 3-way comparison. There
612 is also a new C API PyObject_RichCompare() (which also falls back on
613 the old 3-way comparison, but does not constrain the outcome of the
614 rich comparison to a Boolean result).
615
616 The rich comparison function takes two objects (at least one of
617 which is guaranteed to have the type that provided the function) and
618 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
619 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
620 object, which may be NotImplemented (in which case the tp_compare
621 slot function is used as a fallback, if defined).
622
623 Classes can overload individual comparison operators by defining one
624 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +0000625 __ge__. There are no explicit "reflected argument" versions of
626 these; instead, __lt__ and __gt__ are each other's reflection,
627 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
628 reflection (similar at the C level). No other implications are
629 made; in particular, Python does not assume that == is the Boolean
630 inverse of !=, or that < is the Boolean inverse of >=. This makes
631 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +0000632
633 Classes or types that want to implement (in)equality tests but not
634 the ordering operators (i.e. unordered types) should implement ==
635 and !=, and raise an error for the ordering operators.
636
Guido van Rossuma88479f2001-01-18 14:28:08 +0000637 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +0000638 Boolean; e.g. a matrix type might want to return a matrix of bits
639 for A < B, giving elementwise comparisons. Such types should ensure
640 that any interpretation of their value in a Boolean context raises
641 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
642 at the C level) to always raise an exception.
643
Guido van Rossuma88479f2001-01-18 14:28:08 +0000644- Complex numbers use rich comparisons to define == and != but raise
645 an exception for <, <=, > and >=. Unfortunately, this also means
646 that cmp() of two complex numbers raises an exception when the two
647 numbers differ. Since it is not mathematically meaningful to compare
648 complex numbers except for equality, I hope that this doesn't break
649 too much code.
650
Tim Peters3389f192001-02-18 08:48:49 +0000651- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +0000652 not defined by the language, other than that it's arbitrary but
653 consistent (see the Reference Manual). An implementation detail changed
654 in 2.1a1 such that None now compares less than any other object. Code
655 relying on this new behavior (like code that relied on the previous
656 behavior) does so at its own risk.
657
Barry Warsaw573b5412001-01-15 20:43:18 +0000658- Functions and methods now support getting and setting arbitrarily
659 named attributes (PEP 232). Functions have a new __dict__
660 (a.k.a. func_dict) which hold the function attributes. Methods get
661 and set attributes on their underlying im_func. It is a TypeError
662 to set an attribute on a bound method.
663
Guido van Rossum051e3352001-01-15 19:11:10 +0000664- The xrange() object implementation has been improved so that
665 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
666 limitation that in this case len(xrange(sys.maxint)) can't be
667 calculated, but the common idiom "for i in xrange(sys.maxint)" will
668 work fine as long as the index i doesn't actually reach 2**31.
669 (Python uses regular ints for sequence and string indices; fixing
670 that is much more work.)
671
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000672- Two changes to from...import:
673
Guido van Rossumba381232001-02-03 15:06:40 +0000674 1) "from M import X" now works even if (after loading module M)
675 sys.modules['M'] is not a real module; it's basically a getattr()
676 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000677
678 2) "from M import *" now looks for M.__all__ to decide which names to
679 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
680 filters out names starting with '_' as before. Whether or not
681 __all__ exists, there's no restriction on the type of M.
682
Guido van Rossumf61f1662001-01-10 20:13:55 +0000683- File objects have a new method, xreadlines(). This is the fastest
684 way to iterate over all lines in a file:
685
686 for line in file.xreadlines():
687 ...do something to line...
688
689 See the xreadlines module (mentioned below) for how to do this for
690 other file-like objects.
691
692- Even if you don't use file.xreadlines(), you may expect a speedup on
693 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +0000694 quite a bit in platform-specific ways: on systems (like Linux) that
695 support flockfile(), getc_unlocked(), and funlockfile(), those are
696 used by default. On systems (like Windows) without getc_unlocked(),
697 a complicated (but still thread-safe) method using fgets() is used by
698 default.
699
Tim Petersd52269b2001-01-25 06:23:18 +0000700 You can force use of the fgets() method by #define'ing
701 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +0000702 getc_unlocked()).
703
Tim Petersd52269b2001-01-25 06:23:18 +0000704 You can force fgets() not to be used by #define'ing
705 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +0000706 test_bufio.py fails -- and let us know if it does!).
707
708- In addition, the fileinput module, while still slower than the other
709 methods on most platforms, has been sped up too, by using
710 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +0000711
712- Support for run-time warnings has been added, including a new
713 command line option (-W) to specify the disposition of warnings.
714 See the description of the warnings module below.
715
716- Extensive changes have been made to the coercion code. This mostly
717 affects extension modules (which can now implement mixed-type
718 numerical operators without having to use coercion), but
719 occasionally, in boundary cases the coercion semantics have changed
720 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +0000721 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +0000722 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +0000723 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +0000724
Guido van Rossumf98eda02001-01-17 15:54:45 +0000725- In connection with the coercion changes, a new built-in singleton
726 object, NotImplemented is defined. This can be returned for
727 operations that wish to indicate they are not implemented for a
728 particular combination of arguments. From C, this is
729 Py_NotImplemented.
730
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +0000731- The interpreter accepts now bytecode files on the command line even
732 if they do not have a .pyc or .pyo extension. On Linux, after executing
733
Martin v. Löwise214baa2001-02-04 22:37:56 +0000734import imp,sys,string
735magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
736reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
737open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +0000738
739 any byte code file can be used as an executable (i.e. as an argument
740 to execve(2)).
741
Tim Peters9940b802000-12-01 07:59:35 +0000742- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +0000743 character. In 1.6 and earlier, they never produced a sign,
744 and raised an error if the value of the long was too large
745 to fit in a Python int. In 2.0, they produced a sign if and
746 only if too large to fit in an int. This was inconsistent
747 across platforms (because the size of an int varies across
748 platforms), and inconsistent with hex() and oct(). Example:
749
750 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +0000751 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +0000752 'ffffffbe' # in 2.0 and before, on 32-bit machines
753 >>> hex(-0x42L)
754 '-0x42L' # in all versions of Python
755
Tim Peters9940b802000-12-01 07:59:35 +0000756 The behavior of %d formats for negative Python longs remains
757 the same as in 2.0 (although in 1.6 and before, they raised
758 an error if the long didn't fit in a Python int).
759
760 %u formats don't make sense for Python longs, but are allowed
761 and treated the same as %d in 2.1. In 2.0, a negative long
762 formatted via %u produced a sign if and only if too large to
763 fit in an int. In 1.6 and earlier, a negative long formatted
764 via %u raised an error if it was too big to fit in an int.
765
Guido van Rossum3661d392000-12-12 22:10:31 +0000766- Dictionary objects have an odd new method, popitem(). This removes
767 an arbitrary item from the dictionary and returns it (in the form of
768 a (key, value) pair). This can be useful for algorithms that use a
769 dictionary as a bag of "to do" items and repeatedly need to pick one
770 item. Such algorithms normally end up running in quadratic time;
771 using popitem() they can usually be made to run in linear time.
772
Tim Peters36cdad12000-12-29 02:06:45 +0000773Standard library
774
Thomas Woutersfe385252001-01-19 23:16:56 +0000775- In the time module, the time argument to the functions strftime,
776 localtime, gmtime, asctime and ctime is now optional, defaulting to
777 the current time (in the local timezone).
778
Guido van Rossumda91f222001-01-15 16:36:08 +0000779- The ftplib module now defaults to passive mode, which is deemed a
780 more useful default given that clients are often inside firewalls
781 these days. Note that this could break if ftplib is used to connect
782 to a *server* that is inside a firewall, from outside; this is
783 expected to be a very rare situation. To fix that, you can call
784 ftp.set_pasv(0).
785
Martin v. Löwis10a27872001-01-13 09:54:41 +0000786- The module site now treats .pth files not only for path configuration,
787 but also supports extensions to the initialization code: Lines starting
788 with import are executed.
789
Guido van Rossumf61f1662001-01-10 20:13:55 +0000790- There's a new module, warnings, which implements a mechanism for
791 issuing and filtering warnings. There are some new built-in
792 exceptions that serve as warning categories, and a new command line
793 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
794 turns warnings into errors). warnings.warn(message[, category])
795 issues a warning message; this can also be called from C as
796 PyErr_Warn(category, message).
797
798- A new module xreadlines was added. This exports a single factory
799 function, xreadlines(). The intention is that this code is the
800 absolutely fastest way to iterate over all lines in an open
801 file(-like) object:
802
803 import xreadlines
804 for line in xreadlines.xreadlines(file):
805 ...do something to line...
806
807 This is equivalent to the previous the speed record holder using
808 file.readlines(sizehint). Note that if file is a real file object
809 (as opposed to a file-like object), this is equivalent:
810
811 for line in file.xreadlines():
812 ...do something to line...
813
Tim Peters36cdad12000-12-29 02:06:45 +0000814- The bisect module has new functions bisect_left, insort_left,
815 bisect_right and insort_right. The old names bisect and insort
816 are now aliases for bisect_right and insort_right. XXX_right
817 and XXX_left methods differ in what happens when the new element
818 compares equal to one or more elements already in the list: the
819 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +0000820 right. Code that doesn't care where equal elements end up should
821 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +0000822
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +0000823- The new curses.panel module wraps the panel library that forms part
824 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
825
Guido van Rossumf61f1662001-01-10 20:13:55 +0000826- The SocketServer module now sets the allow_reuse_address flag by
827 default in the TCPServer class.
828
829- A new function, sys._getframe(), returns the stack frame pointer of
830 the caller. This is intended only as a building block for
831 higher-level mechanisms such as string interpolation.
832
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000833- The pyexpat module supports a number of new handlers, which are
834 available only in expat 1.2. If invocation of a callback fails, it
835 will report an additional frame in the traceback. Parser objects
836 participate now in garbage collection. If expat reports an unknown
837 encoding, pyexpat will try to use a Python codec; that works only
838 for single-byte charsets. The parser type objects is exposed as
839 XMLParserObject.
840
841- xml.dom now offers standard definitions for symbolic node type and
842 exception code constants, and a hierarchy of DOM exceptions. minidom
843 was adjusted to use them.
844
845- The conformance of xml.dom.minidom to the DOM specification was
846 improved. It detects a number of additional error cases; the
847 previous/next relationship works even when the tree is modified;
848 Node supports the normalize() method; NamedNodeMap, DocumentType and
849 DOMImplementation classes were added; Element supports the
850 hasAttribute and hasAttributeNS methods; and Text supports the splitText
851 method.
852
Guido van Rossumf61f1662001-01-10 20:13:55 +0000853Build issues
854
Guido van Rossum1e33bdc2001-01-23 03:17:00 +0000855- For Unix (and Unix-compatible) builds, configuration and building of
856 extension modules is now greatly automated. Rather than having to
857 edit the Modules/Setup file to indicate which modules should be
858 built and where their include files and libraries are, a
859 distutils-based setup.py script now takes care of building most
860 extension modules. All extension modules built this way are built
861 as shared libraries. Only a few modules that must be linked
862 statically are still listed in the Setup file; you won't need to
863 edit their configuration.
864
865- Python should now build out of the box on Cygwin. If it doesn't,
866 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +0000867
868- Python now always uses its own (renamed) implementation of getopt()
869 -- there's too much variation among C library getopt()
870 implementations.
871
872- C++ compilers are better supported; the CXX macro is always set to a
873 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +0000874
Tim Petersd92dfe02000-12-12 01:18:41 +0000875Windows changes
876
877- select module: By default under Windows, a select() call
878 can specify no more than 64 sockets. Python now boosts
879 this Microsoft default to 512. If you need even more than
880 that, see the MS docs (you'll need to #define FD_SETSIZE
881 and recompile Python from source).
882
Guido van Rossumf61f1662001-01-10 20:13:55 +0000883- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
884 subdirectory is no more!
885
Tim Petersa3a3a032000-11-30 05:22:44 +0000886
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000887What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +0000888=========================
Guido van Rossum61000331997-08-15 04:39:58 +0000889
Guido van Rossum8ed602b2000-09-01 22:34:33 +0000890Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000891changes are in the file HISTORY. If you are making the jump directly
892from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
893HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +0000894
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000895Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
896the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
897http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +0000898
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000899--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +0000900
901======================================================================
902
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000903What's new in 2.0 (since release candidate 1)?
904==============================================
905
906Standard library
907
908- The copy_reg module was modified to clarify its intended use: to
909 register pickle support for extension types, not for classes.
910 pickle() will raise a TypeError if it is passed a class.
911
912- Fixed a bug in gettext's "normalize and expand" code that prevented
913 it from finding an existing .mo file.
914
915- Restored support for HTTP/0.9 servers in httplib.
916
Tim Peters989b7b92000-10-16 20:24:53 +0000917- The math module was changed to stop raising OverflowError in case of
918 underflow, and return 0 instead in underflow cases. Whether Python
919 used to raise OverflowError in case of underflow was platform-
920 dependent (it did when the platform math library set errno to ERANGE
921 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000922
923- Fixed a bug in StringIO that occurred when the file position was not
924 at the end of the file and write() was called with enough data to
925 extend past the end of the file.
926
927- Fixed a bug that caused Tkinter error messages to get lost on
928 Windows. The bug was fixed by replacing direct use of
929 interp->result with Tcl_GetStringResult(interp).
930
931- Fixed bug in urllib2 that caused it to fail when it received an HTTP
932 redirect response.
933
934- Several changes were made to distutils: Some debugging code was
935 removed from util. Fixed the installer used when an external zip
936 program (like WinZip) is not found; the source code for this
937 installer is in Misc/distutils. check_lib() was modified to behave
938 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
939 test for whether installed modules are on sys.path was changed to
940 use both normcase() and normpath().
941
Jeremy Hyltond867a2c2000-10-16 20:41:38 +0000942- Several minor bugs were fixed in the xml package (the minidom,
943 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000944
945- The regression test driver (regrtest.py) behavior when invoked with
946 -l changed: It now reports a count of objects that are recognized as
947 garbage but not freed by the garbage collector.
948
Tim Peters989b7b92000-10-16 20:24:53 +0000949- The regression test for the math module was changed to test
950 exceptional behavior when the test is run in verbose mode. Python
951 cannot yet guarantee consistent exception behavior across platforms,
952 so the exception part of test_math is run only in verbose mode, and
953 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000954
955Internals
956
957- PyOS_CheckStack() has been disabled on Win64, where it caused
958 test_sre to fail.
959
960Build issues
961
962- Changed compiler flags, so that gcc is always invoked with -Wall and
963 -Wstrict-prototypes. Users compiling Python with GCC should see
964 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +0000965 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +0000966 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000967
Tim Petersa3a3a032000-11-30 05:22:44 +0000968- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000969
970Tools and other miscellany
971
972- The compiler in Tools/compiler was updated to support the new
973 language features introduced in 2.0: extended print statement, list
974 comprehensions, and augmented assignments. The new compiler should
975 also be backwards compatible with Python 1.5.2; the compiler will
976 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +0000977 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000978
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000979What's new in 2.0 release candidate 1 (since beta 2)?
980=====================================================
981
Jeremy Hylton6040aaa2000-10-09 21:27:22 +0000982What is release candidate 1?
983
984We believe that release candidate 1 will fix all known bugs that we
985intend to fix for the 2.0 final release. This release should be a bit
986more stable than the previous betas. We would like to see even more
987widespread testing before the final release, so we are producing this
988release candidate. The final release will be exactly the same unless
989any show-stopping (or brown bag) bugs are found by testers of the
990release candidate.
991
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000992All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000993to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000994
995Core language, builtins, and interpreter
996
997- A bug that caused crashes when __coerce__ was used with augmented
998 assignment, e.g. +=, was fixed.
999
1000- Raise ZeroDivisionError when raising zero to a negative number,
1001 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1002 power operator and the result of math.pow(0.0, -2.0) will vary by
1003 platform. On Linux, it raises a ValueError.
1004
1005- A bug in Unicode string interpolation was fixed that occasionally
1006 caused errors with formats including "%%". For example, the
1007 following expression "%% %s" % u"abc" no longer raises a TypeError.
1008
1009- Compilation of deeply nested expressions raises MemoryError instead
1010 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1011
1012- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1013 rendering them useless. They are now written in binary mode again.
1014
1015Standard library
1016
1017- Keyword arguments are now accepted for most pattern and match object
1018 methods in SRE, the standard regular expression engine.
1019
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001020- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001021 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001022
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001023- Several bugs in the Unicode handling and error handling in _tkinter
1024 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001025
1026- Fix memory management errors in Merge() and Tkapp_Call() routines.
1027
1028- Several changes were made to cStringIO to make it compatible with
1029 the file-like object interface and with StringIO. If operations are
1030 performed on a closed object, an exception is raised. The truncate
1031 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001032 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001033
1034- There were many changes made to the linuxaudiodev module and its
1035 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001036 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001037
1038 Note that this module is named poorly, because it should work
1039 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001040 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001041
1042 The module now raises exceptions when errors occur instead of
1043 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1044 audio) and defines a getptr() method that calls the
1045 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1046
1047- The library_version attribute, introduced in an earlier beta, was
1048 removed because it can not be supported with early versions of the C
1049 readline library, which provides no way to determine the version at
1050 compile-time.
1051
1052- The binascii module is now enabled on Win64.
1053
Tim Peters46446d62000-10-09 21:19:31 +00001054- tokenize.py no longer suffers "recursion depth" errors when parsing
1055 programs with very long string literals.
1056
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001057Internals
1058
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001059- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001060 which is called when the interpreter starts up to determine where
1061 the standard library is installed. These vulnerabilities affect all
1062 previous versions of Python and can be exploited by setting very
1063 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1064 setuid Python script, although use of the wrapper in
1065 Misc/setuid-prog.c will eliminate the vulnerability.
1066
1067- Fixed garbage collection bugs in instance creation that were
1068 triggered when errors occurred during initialization. The solution,
1069 applied in cPickle and in PyInstance_New(), is to call
1070 PyObject_GC_Init() after the initialization of the object's
1071 container attributes is complete.
1072
1073- pyexpat adds definitions of PyModule_AddStringConstant and
1074 PyModule_AddObject if the Python version is less than 2.0, which
1075 provides compatibility with PyXML on Python 1.5.2.
1076
1077- If the platform has a bogus definition for LONG_BIT (the number of
1078 bits in a long), an error will be reported at compile time.
1079
1080- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1081 collection crashes and possibly other, unreported crashes.
1082
1083- Fixed a memory leak in _PyUnicode_Fini().
1084
1085Build issues
1086
1087- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001088 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001089 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001090
1091- The mmap.PAGESIZE constant is now initialized using sysconf when
1092 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1093
1094- The md5 file should now compile on all platforms.
1095
1096- The select module now compiles on platforms that do not define
1097 POLLRDNORM and related constants.
1098
1099- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001100 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001101
Jeremy Hylton10921202000-10-09 18:34:12 +00001102- BeOS: A number of changes were made to the build and installation
1103 process. ar-fake now operates on a directory of object files.
1104 dl_export.h is gone, and its macros now appear on the mwcc command
1105 line during build on PPC BeOS.
1106
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001107- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001108 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001109
1110- Cygwin: Support for shared libraries, Tkinter, and sockets.
1111
1112- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1113
1114Tools and other miscellany
1115
1116- Removed debugging prints from main used with freeze.
1117
Tim Peters46446d62000-10-09 21:19:31 +00001118- IDLE auto-indent no longer crashes when it encounters Unicode
1119 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001120
1121What's new in 2.0 beta 2 (since beta 1)?
1122========================================
1123
1124Core language, builtins, and interpreter
1125
Tim Peters482c0212000-09-26 06:33:09 +00001126- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001127 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001128
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001129- Add -h and -V command line options to print the usage message and
1130 Python version number and exit immediately.
1131
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001132- eval() and exec accept Unicode objects as code parameters.
1133
1134- getattr() and setattr() now also accept Unicode objects for the
1135 attribute name, which are converted to strings using the default
1136 encoding before lookup.
1137
1138- Multiplication on string and Unicode now does proper bounds
1139 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1140 string is too long."
1141
1142- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001143 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001144
Jeremy Hylton1b618592000-09-26 05:32:36 +00001145
1146Standard library and extensions
1147
Guido van Rossum5b08f132001-04-16 02:05:23 +00001148- socket module: the OpenSSL code now adds support for RAND_status()
1149 and EGD (Entropy Gathering Device).
1150
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001151- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001152 argument checking; it still takes no arguments.
1153
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001154- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001155
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001156- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001157
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001158- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001159
1160- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001161 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001162
1163- copy: Copy Unicode objects atomically.
1164
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001165- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001166
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001167- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001168
Fred Drake67233bc2000-09-26 16:40:27 +00001169- dbm: Add get() and setdefault() methods to dbm object. Add constant
1170 `library' to module that names the library used. Added doc strings
1171 and method names to error messages. Uses configure to determine
1172 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
1173 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001174
1175- distutils: Update to version 0.9.3.
1176
1177- dl: Add several dl.RTLD_ constants.
1178
1179- fpectl: Now supported on FreeBSD.
1180
1181- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
1182 found by the collector will be saved in gc.garbage. This is useful
1183 for debugging a program that creates reference cycles.
1184
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001185- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00001186 of HTTP class. Do not close socket on zero-length response. Do not
1187 crash when server sends invalid content-length header.
1188
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001189- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001190
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001191- marshal: When reading a short, sign-extend on platforms where shorts
1192 are bigger than 16 bits. When reading a long, repair the unportable
1193 sign extension that was being done for 64-bit machines. (It assumed
1194 that signed right shift sign-extends.)
1195
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001196- operator: Add contains(), invert(), __invert__() as aliases for
1197 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001198
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001199- os: Add support for popen2() and popen3() on all platforms where
1200 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001201
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001202- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00001203 clicking on a file in Explorer (or passing the file name to the
1204 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001205
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001206- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00001207 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001208
1209- pickle: Now raises ValueError when an invalid pickle that contains
1210 a non-string repr where a string repr was expected. This behavior
1211 matches cPickle.
1212
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001213- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001214
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001215- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001216
1217- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001218 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001219 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001220
1221- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001222 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001223
1224- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00001225 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00001226 few cycles during startup since the first call to
1227 setdefaultencoding() will initialize the codec registry and the
1228 encodings package.
1229
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001230- socket: Support for size hint in readlines() method of object returned
1231 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001232
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001233- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001234 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001235 is followed by whitespace.
1236
Tim Petersa3a3a032000-11-30 05:22:44 +00001237- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001238
1239- struct: Check ranges for bytes and shorts.
1240
1241- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001242 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001243
1244- Tkinter: Image objects are now guaranteed to have unique ids. Set
1245 event.delta to zero if Tk version doesn't support mousewheel.
1246 Removed some debugging prints.
1247
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001248- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001249
Fred Drake67233bc2000-09-26 16:40:27 +00001250- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001251 which works around a bug in Norton AntiVirus 2000 that leads directly
1252 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001253
1254- xml: New version detection code allows PyXML to override standard
1255 XML package if PyXML version is greater than 0.6.1.
1256
Fred Drake64bb3802000-09-26 16:21:35 +00001257- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
1258 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
1259 tree only for nodes which are sufficiently interesting to a specific
1260 application. Does not provide the HTML-specific extensions. Still
1261 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001262
Fred Drake64bb3802000-09-26 16:21:35 +00001263- xml.sax: SAX 2 support for Python, including all the handler
1264 interfaces needed to process XML 1.0 compliant XML. Some
1265 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001266
Fred Drake64bb3802000-09-26 16:21:35 +00001267- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
1268 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001269
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001270
Jeremy Hylton1b618592000-09-26 05:32:36 +00001271C API
1272
1273- Add three new convenience functions for module initialization --
1274 PyModule_AddObject(), PyModule_AddIntConstant(), and
1275 PyModule_AddStringConstant().
1276
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001277- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00001278 removed and add #error to Python.h if NULL isn't defined after
1279 #include of stdio.h.
1280
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001281- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00001282 backwards compatibility (at the source level) with old extensions.
1283
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001284- A wrapper API was added for signal() and sigaction(). Instead of
1285 either function, always use PyOS_getsig() to get a signal handler
1286 and PyOS_setsig() to set one. A new convenience typedef
1287 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001288
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001289- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00001290 internal data buffer and size of a string object -- or the default
1291 encoded version of a Unicode object.
1292
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001293- PyString_Size() and PyString_AsString() accept Unicode objects.
1294
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001295- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00001296 exists). INT_MAX and LONG_MAX will always be defined, even if
1297 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001298
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001299- PyFloat_FromString takes a second argument, pend, that was
1300 effectively useless. It is now officially useless but preserved for
1301 backwards compatibility. If the pend argument is not NULL, *pend is
1302 set to NULL.
1303
1304- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
1305 for the attribute name. See note on getattr() above.
1306
1307- A few bug fixes to argument processing for Unicode.
1308 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
1309 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
1310 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00001311 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001312
1313- Py_BuildValue accepts B format (for bgen-generated code).
1314
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001315
Jeremy Hylton1b618592000-09-26 05:32:36 +00001316Internals
1317
1318- On Unix, fix code for finding Python installation directory so that
1319 it works when argv[0] is a relative path.
1320
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00001321- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001322 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00001323 rather than by generating a copy of the object.
1324
Tim Peters482c0212000-09-26 06:33:09 +00001325- Several of the internal Unicode tables are much smaller now, and
1326 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001327
Jeremy Hylton97693b02000-09-26 17:42:51 +00001328- In the garbage collector: Fixed bug in collection of tuples. Fixed
1329 bug that caused some instances to be removed from the container set
1330 while they were still live. Fixed parsing in gc.set_debug() for
1331 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001332
1333- Fixed refcount problem in instance deallocation that only occurred
1334 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
1335
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001336- On Windows, getpythonregpath is now protected against null data in
1337 registry key.
1338
1339- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00001340 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001341
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001342
Jeremy Hylton1b618592000-09-26 05:32:36 +00001343Build and platform-specific issues
1344
1345- Better support of GNU Pth via --with-pth configure option.
1346
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001347- Python/C API now properly exposed to dynamically-loaded extension
1348 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001349
1350- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
1351 Don't define MS_SYNC to be zero when it is undefined. Added missing
1352 prototypes in posixmodule.c.
1353
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001354- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001355 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001356
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001357- Fix largefile support on older NetBSD systems and OpenBSD by adding
1358 define for TELL64.
1359
1360
1361Tools and other miscellany
1362
1363- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
1364
1365- freeze: The modulefinder now works with 2.0 opcodes.
1366
Tim Petersa3a3a032000-11-30 05:22:44 +00001367- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001368 Move hackery of sys.argv until after the Tk instance has been
1369 created, which allows the application-specific Tkinter
1370 initialization to be executed if present; also pass an explicit
1371 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00001372
Jeremy Hylton1b618592000-09-26 05:32:36 +00001373
1374What's new in 2.0 beta 1?
1375=========================
1376
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001377Source Incompatibilities
1378------------------------
1379
1380None. Note that 1.6 introduced several incompatibilities with 1.5.2,
1381such as single-argument append(), connect() and bind(), and changes to
1382str(long) and repr(float).
1383
1384
1385Binary Incompatibilities
1386------------------------
1387
1388- Third party extensions built for Python 1.5.x or 1.6 cannot be used
1389with Python 2.0; these extensions will have to be rebuilt for Python
13902.0.
1391
1392- On Windows, attempting to import a third party extension built for
1393Python 1.5.x or 1.6 results in an immediate crash; there's not much we
1394can do about this. Check your PYTHONPATH environment variable!
1395
1396- Python bytecode files (*.pyc and *.pyo) are not compatible between
1397releases.
1398
1399
1400Overview of Changes Since 1.6
1401-----------------------------
1402
1403There are many new modules (including brand new XML support through
1404the xml package, and i18n support through the gettext module); a list
1405of all new modules is included below. Lots of bugs have been fixed.
1406
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001407The process for making major new changes to the language has changed
1408since Python 1.6. Enhancements must now be documented by a Python
1409Enhancement Proposal (PEP) before they can be accepted.
1410
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001411There are several important syntax enhancements, described in more
1412detail below:
1413
1414 - Augmented assignment, e.g. x += 1
1415
1416 - List comprehensions, e.g. [x**2 for x in range(10)]
1417
1418 - Extended import statement, e.g. import Module as Name
1419
1420 - Extended print statement, e.g. print >> file, "Hello"
1421
1422Other important changes:
1423
1424 - Optional collection of cyclical garbage
1425
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001426Python Enhancement Proposal (PEP)
1427---------------------------------
1428
1429PEP stands for Python Enhancement Proposal. A PEP is a design
1430document providing information to the Python community, or describing
1431a new feature for Python. The PEP should provide a concise technical
1432specification of the feature and a rationale for the feature.
1433
1434We intend PEPs to be the primary mechanisms for proposing new
1435features, for collecting community input on an issue, and for
1436documenting the design decisions that have gone into Python. The PEP
1437author is responsible for building consensus within the community and
1438documenting dissenting opinions.
1439
1440The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001441
1442Augmented Assignment
1443--------------------
1444
1445This must have been the most-requested feature of the past years!
1446Eleven new assignment operators were added:
1447
Guido van Rossume905e952000-09-05 12:42:46 +00001448 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001449
1450For example,
1451
1452 A += B
1453
1454is similar to
1455
1456 A = A + B
1457
1458except that A is evaluated only once (relevant when A is something
1459like dict[index].attr).
1460
1461However, if A is a mutable object, A may be modified in place. Thus,
1462if A is a number or a string, A += B has the same effect as A = A+B
1463(except A is only evaluated once); but if a is a list, A += B has the
1464same effect as A.extend(B)!
1465
1466Classes and built-in object types can override the new operators in
1467order to implement the in-place behavior; the not-in-place behavior is
1468used automatically as a fallback when an object doesn't implement the
1469in-place behavior. For classes, the method name is derived from the
1470method name for the corresponding not-in-place operator by inserting
1471an 'i' in front of the name, e.g. __iadd__ implements in-place
1472__add__.
1473
1474Augmented assignment was implemented by Thomas Wouters.
1475
1476
1477List Comprehensions
1478-------------------
1479
1480This is a flexible new notation for lists whose elements are computed
1481from another list (or lists). The simplest form is:
1482
1483 [<expression> for <variable> in <sequence>]
1484
Guido van Rossum56db0952000-09-06 23:34:25 +00001485For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001486This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001487
1488You can also add a condition:
1489
1490 [<expression> for <variable> in <sequence> if <condition>]
1491
1492For example, [w for w in words if w == w.lower()] would yield the list
1493of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001494than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001495
1496You can also have nested for loops and more than one 'if' clause. For
1497example, here's a function that flattens a sequence of sequences::
1498
1499 def flatten(seq):
1500 return [x for subseq in seq for x in subseq]
1501
1502 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
1503
1504This prints
1505
1506 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
1507
1508List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001509Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001510
1511
1512Extended Import Statement
1513-------------------------
1514
1515Many people have asked for a way to import a module under a different
1516name. This can be accomplished like this:
1517
1518 import foo
1519 bar = foo
1520 del foo
1521
1522but this common idiom gets old quickly. A simple extension of the
1523import statement now allows this to be written as follows:
1524
1525 import foo as bar
1526
1527There's also a variant for 'from ... import':
1528
1529 from foo import bar as spam
1530
1531This also works with packages; e.g. you can write this:
1532
1533 import test.regrtest as regrtest
1534
1535Note that 'as' is not a new keyword -- it is recognized only in this
1536context (this is only possible because the syntax for the import
1537statement doesn't involve expressions).
1538
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001539Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001540
1541
1542Extended Print Statement
1543------------------------
1544
1545Easily the most controversial new feature, this extension to the print
1546statement adds an option to make the output go to a different file
1547than the default sys.stdout.
1548
1549For example, to write an error message to sys.stderr, you can now
1550write:
1551
1552 print >> sys.stderr, "Error: bad dog!"
1553
1554As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00001555evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001556
1557 print >> None, "Hello world"
1558
1559is equivalent to
1560
1561 print "Hello world"
1562
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001563Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001564
1565
1566Optional Collection of Cyclical Garbage
1567---------------------------------------
1568
1569Python is now equipped with a garbage collector that can hunt down
1570cyclical references between Python objects. It's no replacement for
1571reference counting; in fact, it depends on the reference counts being
1572correct, and decides that a set of objects belong to a cycle if all
1573their reference counts can be accounted for from their references to
1574each other. This devious scheme was first proposed by Eric Tiedemann,
1575and brought to implementation by Neil Schemenauer.
1576
1577There's a module "gc" that lets you control some parameters of the
1578garbage collection. There's also an option to the configure script
1579that lets you enable or disable the garbage collection. In 2.0b1,
1580it's on by default, so that we (hopefully) can collect decent user
1581experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00001582performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001583off by default in the final 2.0 release.
1584
1585
1586Smaller Changes
1587---------------
1588
1589A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
1590map(None, seq1, seq2, ...) when the sequences have the same length;
1591i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
1592the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001593zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001594
1595sys.version_info is a tuple (major, minor, micro, level, serial).
1596
1597Dictionaries have an odd new method, setdefault(key, default).
1598dict.setdefault(key, default) returns dict[key] if it exists; if not,
1599it sets dict[key] to default and returns that value. Thus:
1600
1601 dict.setdefault(key, []).append(item)
1602
1603does the same work as this common idiom:
1604
1605 if not dict.has_key(key):
1606 dict[key] = []
1607 dict[key].append(item)
1608
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001609There are two new variants of SyntaxError that are raised for
1610indentation-related errors: IndentationError and TabError.
1611
1612Changed \x to consume exactly two hex digits; see PEP 223. Added \U
1613escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001614
1615The limits on the size of expressions and file in Python source code
1616have been raised from 2**16 to 2**32. Previous versions of Python
1617were limited because the maximum argument size the Python VM accepted
1618was 2**16. This limited the size of object constructor expressions,
1619e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
1620limit was raised thanks to a patch by Charles Waldman that effectively
1621fixes the problem. It is now much more likely that you will be
1622limited by available memory than by an arbitrary limit in Python.
1623
1624The interpreter's maximum recursion depth can be modified by Python
1625programs using sys.getrecursionlimit and sys.setrecursionlimit. This
1626limit is the maximum number of recursive calls that can be made by
1627Python code. The limit exists to prevent infinite recursion from
1628overflowing the C stack and causing a core dump. The default value is
16291000. The maximum safe value for a particular platform can be found
1630by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001631
1632New Modules and Packages
1633------------------------
1634
1635atexit - for registering functions to be called when Python exits.
1636
1637imputil - Greg Stein's alternative API for writing custom import
1638hooks.
1639
1640pyexpat - an interface to the Expat XML parser, contributed by Paul
1641Prescod.
1642
1643xml - a new package with XML support code organized (so far) in three
1644subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
1645would fill a volume. There's a special feature whereby a
1646user-installed package named _xmlplus overrides the standard
1647xmlpackage; this is intended to give the XML SIG a hook to distribute
1648backwards-compatible updates to the standard xml package.
1649
1650webbrowser - a platform-independent API to launch a web browser.
1651
1652
Guido van Rossume905e952000-09-05 12:42:46 +00001653Changed Modules
1654---------------
1655
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001656array -- new methods for array objects: count, extend, index, pop, and
1657remove
1658
1659binascii -- new functions b2a_hex and a2b_hex that convert between
1660binary data and its hex representation
1661
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001662calendar -- Many new functions that support features including control
1663over which day of the week is the first day, returning strings instead
1664of printing them. Also new symbolic constants for days of week,
1665e.g. MONDAY, ..., SUNDAY.
1666
1667cgi -- FieldStorage objects have a getvalue method that works like a
1668dictionary's get method and returns the value attribute of the object.
1669
1670ConfigParser -- The parser object has new methods has_option,
1671remove_section, remove_option, set, and write. They allow the module
1672to be used for writing config files as well as reading them.
1673
1674ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00001675optionally support the RFC 959 REST command.
1676
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001677gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00001678
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001679httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
1680the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00001681
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001682locale -- implement getdefaultlocale for Win32 and Macintosh
1683
1684marshal -- no longer dumps core when marshaling deeply nested or
1685recursive data structures
1686
1687os -- new functions isatty, seteuid, setegid, setreuid, setregid
1688
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001689os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
1690support under Unix.
1691
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001692os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001693
1694os.path -- fix semantics of os.path.commonprefix
1695
1696smtplib -- support for sending very long messages
1697
1698socket -- new function getfqdn()
1699
1700readline -- new functions to read, write and truncate history files.
1701The readline section of the library reference manual contains an
1702example.
1703
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001704select -- add interface to poll system call
1705
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001706shutil -- new copyfileobj function
1707
1708SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
1709HTTP server.
1710
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001711Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001712
1713urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00001714e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001715
1716whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00001717
1718
1719Obsolete Modules
1720----------------
1721
1722None. However note that 1.6 made a whole slew of modules obsolete:
1723stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
1724poly, zmod, strop, util, whatsound.
1725
1726
1727Changed, New, Obsolete Tools
1728----------------------------
1729
Tim Peters8b092332000-09-05 20:15:25 +00001730None.
Guido van Rossume905e952000-09-05 12:42:46 +00001731
1732
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001733C-level Changes
1734---------------
1735
1736Several cleanup jobs were carried out throughout the source code.
1737
1738All C code was converted to ANSI C; we got rid of all uses of the
1739Py_PROTO() macro, which makes the header files a lot more readable.
1740
1741Most of the portability hacks were moved to a new header file,
1742pyport.h; several other new header files were added and some old
1743header files were removed, in an attempt to create a more rational set
1744of header files. (Few of these ever need to be included explicitly;
1745they are all included by Python.h.)
1746
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001747Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001748and Win64, especially for the new Intel Itanium processor. Mick also
1749added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001750
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001751The C APIs to return an object's size have been update to consistently
1752use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
1753previous versions, the abstract interfaces used PyXXX_Length and the
1754concrete interfaces used PyXXX_Size. The old names,
1755e.g. PyObject_Length, are still available for backwards compatibility
1756at the API level, but are deprecated.
1757
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001758The PyOS_CheckStack function has been implemented on Windows by
1759Fredrik Lundh. It prevents Python from failing with a stack overflow
1760on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001761
1762The GC changes resulted in creation of two new slots on object,
1763tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00001764the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001765
1766The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00001767C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001768
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001769PyErr_Format has been updated to automatically calculate the size of
1770the buffer needed to hold the formatted result string. This change
1771prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001772
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001773New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00001774
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001775PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
1776that are the same as their non-Ex counterparts except they take an
1777extra flag argument that tells them to close the file when done.
1778
1779XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00001780
Tim Peters8b092332000-09-05 20:15:25 +00001781
1782Windows Changes
1783---------------
1784
1785New popen2/popen3/peopen4 in os module (see Changed Modules above).
1786
1787os.popen is much more usable on Windows 95 and 98. See Microsoft
1788Knowledge Base article Q150956. The Win9x workaround described there
1789is implemented by the new w9xpopen.exe helper in the root of your
1790Python installation. Note that Python uses this internally; it is not
1791a standalone program.
1792
1793Administrator privileges are no longer required to install Python
1794on Windows NT or Windows 2000. If you have administrator privileges,
1795Python's registry info will be written under HKEY_LOCAL_MACHINE.
1796Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00001797under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00001798uses of Python, but will prevent some advanced uses from working
1799(for example, running a Python script as an NT service, or possibly
1800from CGI).
1801
1802[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
1803installer; instead, it installs the needed Tcl/Tk files directly in the
1804Python directory. If you already have a Tcl/Tk installation, this
1805wastes some disk space (about 4 Megs) but avoids problems with
1806conflicting Tcl/Tk installations, and makes it much easier for Python
1807to ensure that Tcl/Tk can find all its files.
1808
1809[This was new in 1.6] The Windows installer now installs by default in
1810\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
1811
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001812
1813Updates to the changes between 1.5.2 and 1.6
1814--------------------------------------------
1815
1816The 1.6 NEWS file can't be changed after the release is done, so here
1817is some late-breaking news:
1818
1819New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
1820and changes to getlocale() and setlocale().
1821
1822The new module is now enabled per default.
1823
1824It is not true that the encodings codecs cannot be used for normal
1825strings: the string.encode() (which is also present on 8-bit strings
1826!) allows using them for 8-bit strings too, e.g. to convert files from
1827cp1252 (Windows) to latin-1 or vice-versa.
1828
1829Japanese codecs are available from Tamito KAJIYAMA:
1830http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
1831
1832
Guido van Rossumab9d6f01998-08-10 22:01:13 +00001833======================================================================