blob: 763a114550b10097ba073935f856fcb14343fcf9 [file] [log] [blame]
Tim Peters84362bc2001-10-19 17:55:30 +00001What's New in Python 2.2b2?
2XXX Planned XXX Release date: 14-Nov-2001
3===========================
4
5Type/class unification and new-style classes
6
Tim Petersa427a2b2001-10-29 22:25:45 +00007- The new builtin dictionary() constructor, and dictionary type, have
8 been renamed to dict. This reflects a decade of common usage.
9
Guido van Rossum7ad2d1e2001-10-29 22:11:00 +000010- New-style classes can now have a __del__ method, which is called
11 when the instance is deleted (just like for classic classes).
12
Guido van Rossum12d955c2001-10-26 14:56:06 +000013- Assignment to object.__dict__ is now possible, for objects that are
14 instances of new-style classes that have a __dict__ (unless the base
15 class forbids it).
16
Tim Peters1fc240e2001-10-26 05:06:50 +000017- dictionary() now accepts an iterable object producing 2-sequences.
18 For example, dictionary(d.items()) == d for any dictionary d. The
19 argument, and the elements of the argument, can be any iterable
20 objects.
21
Guido van Rossumc8e56452001-10-22 00:43:43 +000022- Methods of built-in types now properly check for keyword arguments
23 (formerly these were silently ignored). The only built-in methods
24 that take keyword arguments are __call__, __init__ and __new__.
25
Guido van Rossum86443212001-10-27 22:28:54 +000026- The socket function has been converted to a type; see below.
27
Tim Peters84362bc2001-10-19 17:55:30 +000028Core and builtins
29
Jeremy Hylton249aaed2001-11-09 21:06:24 +000030- Assignment to __debug__ raises SyntaxError at compile-time. This
31 was promised when 2.1c1 was released as "What's New in Python 2.1c1"
32 (below) says.
33
Guido van Rossum12d955c2001-10-26 14:56:06 +000034- Clarified the error messages for unsupported operands to an operator
35 (like 1 + '').
36
Tim Peters84362bc2001-10-19 17:55:30 +000037Extension modules
38
Tim Peters5ebfd362001-11-13 23:11:19 +000039- mmap has a new keyword argument, "access", allowing a uniform way for
40 both Windows and Unix users to create read-only, write-through and
41 copy-on-write memory mappings. This was previously possible only on
42 Unix. A new keyword argument was required to support this in a
43 uniform way because the mmap() signuatures had diverged across
44 platforms. Thanks to Jay T Miller for repairing this!
45
Tim Peters169ded02001-11-03 19:57:21 +000046- By default, the gc.garbage list now contains only those instances in
47 unreachable cycles that have __del__ methods; in 2.1 it contained all
48 instances in unreachable cycles. "Instances" here has been generalized
49 to include instances of both new-style and old-style classes.
50
Guido van Rossum12d955c2001-10-26 14:56:06 +000051- The socket module defines a new method for socket objects,
52 sendall(). This is like send() but may make multiple calls to
Guido van Rossum86443212001-10-27 22:28:54 +000053 send() until all data has been sent. Also, the socket function has
54 been converted to a subclassable type, like list and tuple (etc.)
55 before it; socket and SocketType are now the same thing.
Guido van Rossum12d955c2001-10-26 14:56:06 +000056
57- Various bugfixes to the curses module. There is now a test suite
58 for the curses module (you have to run it manually).
Andrew M. Kuchling15e03532001-10-22 16:37:10 +000059
Guido van Rossum692adf12001-10-30 03:03:03 +000060- binascii.b2a_base64 no longer places an arbitrary restriction of 57
61 bytes on its input.
62
Tim Peters84362bc2001-10-19 17:55:30 +000063Library
64
Tim Peters5ebfd362001-11-13 23:11:19 +000065- tkFileDialog exposes a Directory class and askdirectory
Martin v. Löwis25ee87c2001-11-07 22:38:08 +000066 convenience function.
67
Tim Peters75335872001-11-03 19:35:43 +000068- Symbolic group names in regular expressions must be unique. For
69 example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
70 single name can't mean both "group 1" and "group 2" simultaneously.
71 Python 2.2 detects this error at regexp compilation time; previously,
72 the error went undetected, and results were unpredictable.
73
Martin v. Löwisb7b32602001-11-02 23:48:20 +000074- Tix exposes more commands through the classes DirSelectBox,
75 DirSelectDialog, ListNoteBook, Meter, CheckList, and the
76 methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
77 tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
78
Tim Peters98791af2001-10-23 01:59:54 +000079- Traceback objects are now scanned by cyclic garbage collection, so
80 cycles created by casual use of sys.exc_info() no longer cause
81 permanent memory leaks (provided garbage collection is enabled).
82
Guido van Rossum49192142001-10-24 20:51:44 +000083- os.extsep -- a new variable needed by the RISCOS support. It is the
84 separator used by extensions, and is '.' on all platforms except
85 RISCOS, where it is '/'. There is no need to use this variable
86 unless you have a masochistic desire to port your code to RISCOS.
87
Tim Peters84362bc2001-10-19 17:55:30 +000088Tools/Demos
89
90Build
91
92C API
93
Tim Peters1fc240e2001-10-26 05:06:50 +000094- New function PySequence_Fast_GET_SIZE() returns the size of a non-
95 NULL result from PySequence_Fast(), more quickly than calling
96 PySequence_Size().
97
Tim Peters84362bc2001-10-19 17:55:30 +000098New platforms
99
Guido van Rossum86443212001-10-27 22:28:54 +0000100- We've finally confirmed that this release builds on HP-UX 11.00,
101 *with* threads, and passes the test suite.
102
Tim Peters7a33d8b2001-11-05 02:51:07 +0000103- Thanks to a series of patches from Michael Muller, Python may build
104 again under OS/2 Visual Age C++.
105
Guido van Rossum49192142001-10-24 20:51:44 +0000106- Updated RISCOS port by Dietmar Schwertberger.
107
Tim Peters84362bc2001-10-19 17:55:30 +0000108Tests
109
Andrew M. Kuchling15e03532001-10-22 16:37:10 +0000110- Added a test script for the curses module. It isn't run automatically;
111 regrtest.py must be run with '-u curses' to enable it.
112
Tim Peters84362bc2001-10-19 17:55:30 +0000113Windows
114
115
Tim Petersabf925f2001-09-28 21:53:42 +0000116What's New in Python 2.2b1?
Guido van Rossum1c486092001-10-19 02:05:35 +0000117Release date: 19-Oct-2001
Tim Petersabf925f2001-09-28 21:53:42 +0000118===========================
119
120Type/class unification and new-style classes
121
Guido van Rossum687ae002001-10-15 22:03:32 +0000122- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000123 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +0000124 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000125 remains: the __dict__ of a new-style class is a read-only proxy; you
126 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +0000127 __defined__ attribute of new-style types no longer exists, for lack
128 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +0000129 future a __cache__ may be resurrected with a similar function, if I
130 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +0000131
Tim Peters1c9ca872001-10-04 06:43:12 +0000132- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
133 always returned None, even when there was a class docstring).
134
135- doctest now finds and runs docstrings attached to new-style classes,
136 class methods, static methods, and properties.
137
Guido van Rossum9074ef62001-10-16 21:34:49 +0000138Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +0000139
Guido van Rossuma8bcf802001-10-15 15:53:58 +0000140- A very subtle syntactical pitfall in list comprehensions was fixed.
141 For example: [a+b for a in 'abc', for b in 'def']. The comma in
142 this example is a mistake. Previously, this would silently let 'a'
143 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
144 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
145 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
146 Note that [a for a in <singleton>] is a convoluted way to say
147 [<singleton>] anyway, so it's not like any expressiveness is lost.
148
Guido van Rossum9074ef62001-10-16 21:34:49 +0000149- getattr(obj, name, default) now only catches AttributeError, as
150 documented, rather than returning the default value for all
151 exceptions (which could mask bugs in a __getattr__ hook, for
152 example).
153
Fred Drakecb7a6b52001-10-22 18:41:51 +0000154- Weak reference objects are now part of the core and offer a C API.
Fred Drake934d2a42001-10-18 18:18:06 +0000155 A bug which could allow a core dump when binary operations involved
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000156 proxy reference has been fixed. weakref.ReferenceError is now a
Barry Warsawf6fb1712001-10-19 05:35:40 +0000157 built-in exception.
Fred Drake934d2a42001-10-18 18:18:06 +0000158
Guido van Rossum1c486092001-10-19 02:05:35 +0000159- unicode(obj) now behaves more like str(obj), accepting arbitrary
160 objects, and calling a __unicode__ method if it exists.
161 unicode(obj, encoding) and unicode(obj, encoding, errors) still
Marc-André Lemburgb5507ec2001-10-19 12:02:29 +0000162 require an 8-bit string or character buffer argument.
Guido van Rossum1c486092001-10-19 02:05:35 +0000163
Barry Warsawf6fb1712001-10-19 05:35:40 +0000164- isinstance() now allows any object as the first argument and a
165 class, a type or something with a __bases__ tuple attribute for the
166 second argument. The second argument may also be a tuple of a
167 class, type, or something with __bases__, in which case isinstance()
168 will return true if the first argument is an instance of any of the
169 things contained in the second argument tuple. E.g.
170
171 isinstance(x, (A, B))
172
173 returns true if x is an instance of A or B.
174
Guido van Rossum9074ef62001-10-16 21:34:49 +0000175Extension modules
176
177- thread.start_new_thread() now returns the thread ID (previously None).
178
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000179- binascii has now two quopri support functions, a2b_qp and b2a_qp.
180
Guido van Rossumc524d952001-10-19 01:31:59 +0000181- readline now supports setting the startup_hook and the
182 pre_event_hook, and adds the add_history() function.
Martin v. Löwis0daad592001-09-30 21:09:59 +0000183
Guido van Rossumc524d952001-10-19 01:31:59 +0000184- os and posix supports chroot(), setgroups() and unsetenv() where
185 available. The stat(), fstat(), statvfs() and fstatvfs() functions
186 now return "pseudo-sequences" -- the various fields can now be
187 accessed as attributes (e.g. os.stat("/").st_mtime) but for
188 backwards compatibility they also behave as a fixed-length sequence.
189 Some platform-specific fields (e.g. st_rdev) are only accessible as
Guido van Rossum98bf58f2001-10-18 20:34:25 +0000190 attributes.
191
192- time: localtime(), gmtime() and strptime() now return a
193 pseudo-sequence similar to the os.stat() return value, with
194 attributes like tm_year etc.
Martin v. Löwis16628c92001-10-04 22:46:41 +0000195
Guido van Rossum9074ef62001-10-16 21:34:49 +0000196- Decompression objects in the zlib module now accept an optional
197 second parameter to decompress() that specifies the maximum amount
198 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +0000199
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000200- optional SSL support in the socket module now exports OpenSSL
201 functions RAND_add(), RAND_egd(), and RAND_status(). These calls
202 are useful on platforms like Solaris where OpenSSL does not
Barry Warsawf6fb1712001-10-19 05:35:40 +0000203 automatically seed its PRNG. Also, the keyfile and certfile
204 arguments to socket.ssl() are now optional.
205
206- posixmodule (and by extension, the os module on POSIX platforms) now
207 exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
Jeremy Hyltoncb441432001-10-19 03:40:19 +0000208
Guido van Rossum9074ef62001-10-16 21:34:49 +0000209Library
Guido van Rossum3c288632001-10-16 21:13:49 +0000210
Tim Peters7402f792001-10-02 03:53:41 +0000211- doctest now excludes functions and classes not defined by the module
212 being tested, thanks to Tim Hochberg.
213
Fred Drakecb7a6b52001-10-22 18:41:51 +0000214- HotShot, a new profiler implemented using a C-based callback, has
215 been added. This substantially reduces the overhead of profiling,
216 but it is still quite preliminary. Support modules and
217 documentation will be added in upcoming releases (before 2.2 final).
218
Guido van Rossumc4b09b42001-10-04 10:19:00 +0000219- profile now produces correct output in situations where an exception
220 raised in Python is cleared by C code (e.g. hasattr()). This used
221 to cause wrong output, including spurious claims of recursive
222 functions and attribution of time spent to the wrong function.
223
Tim Peters0a1fc4e2001-10-07 03:12:08 +0000224 The code and documentation for the derived OldProfile and HotProfile
225 profiling classes was removed. The code hasn't worked for years (if
226 you tried to use them, they raised exceptions). OldProfile
227 intended to reproduce the behavior of the profiler Python used more
228 than 7 years ago, and isn't interesting anymore. HotProfile intended
229 to provide a faster profiler (but producing less information), and
230 that's a worthy goal we intend to meet via a different approach (but
231 without losing information).
232
Tim Peterscce092d2001-10-09 05:31:56 +0000233- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +0000234 a much better system-specific calibration constant. The constant can
235 now be specified in an instance constructor, or as a Profile class or
236 instance variable, instead of by editing profile.py's source code.
237 Calibration must still be done manually (see the docs for the profile
238 module).
239
240 Note that Profile.calibrate() must be overriden by subclasses.
241 Improving the accuracy required exploiting detailed knowledge of
242 profiler internals; the earlier method abstracted away the details
243 and measured a simplified model instead, but consequently computed
244 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +0000245
Martin v. Löwis16dc7f42001-09-30 20:32:11 +0000246- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +0000247 which indicates whether output is intended for the header 'Q'
248 encoding.
249
Guido van Rossuma5343cc2001-10-18 18:02:07 +0000250- The SocketServer.ThreadingMixIn class now closes the request after
251 finish_request() returns. (Not when it errors out though.)
252
Barry Warsawf6fb1712001-10-19 05:35:40 +0000253- The nntplib module's NNTP.body() method has grown a `file' argument
254 to allow saving the message body to a file.
255
256- The email package has added a class email.Parser.HeaderParser which
257 only parses headers and does not recurse into the message's body.
258 Also, the module/class MIMEAudio has been added for representing
259 audio data (contributed by Anthony Baxter).
260
261- ftplib should be able to handle files > 2GB.
262
263- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
264 ON, and OFF.
265
Fred Drakecb7a6b52001-10-22 18:41:51 +0000266- xml.dom.minidom NodeList objects now support the length attribute
267 and item() method as required by the DOM specifications.
268
Guido van Rossumed554f62001-10-02 23:15:37 +0000269Tools/Demos
270
271- Demo/dns was removed. It no longer serves any purpose; a package
272 derived from it is now maintained by Anthony Baxter, see
273 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +0000274
Barry Warsawf6fb1712001-10-19 05:35:40 +0000275- The freeze tool has been made more robust, and two new options have
276 been added: -X and -E.
277
Tim Petersabf925f2001-09-28 21:53:42 +0000278Build
279
Barry Warsawf6fb1712001-10-19 05:35:40 +0000280- configure will use CXX in LINKCC if CXX is used to build main() and
281 the system requires to link a C++ main using the C++ compiler.
282
Tim Petersabf925f2001-09-28 21:53:42 +0000283C API
284
Guido van Rossum6c4bce32001-10-18 19:20:25 +0000285- The documentation for the tp_compare slot is updated to require that
286 the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
287 not correct. This is not yet enforced but will be enforced in
288 Python 2.3; even later, we may use -2 to indicate errors and +2 for
289 "NotImplemented". Right now, -1 should be used for an error return.
290
Tim Petersd38b1c72001-09-30 05:09:37 +0000291- PyLong_AsLongLong() now accepts int (as well as long) arguments.
292 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
293 as long) arguments.
294
Guido van Rossum3c288632001-10-16 21:13:49 +0000295- PyThread_start_new_thread() now returns a long int giving the thread
296 ID, if one can be calculated; it returns -1 for error, 0 if no
297 thread ID is calculated (this is an incompatible change, but only
298 the thread module used this API). This code has only really been
299 tested on Linux and Windows; other platforms please beware (and
300 report any bugs or strange behavior).
301
Guido van Rossum1c486092001-10-19 02:05:35 +0000302- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
303 input.
304
Tim Petersabf925f2001-09-28 21:53:42 +0000305New platforms
306
307Tests
308
309Windows
310
Tim Peters04cf1d32001-10-09 22:39:40 +0000311- Installer: If you install IDLE, and don't disable file-extension
312 registration, a new "Edit with IDLE" context (right-click) menu entry
313 is created for .py and .pyw files.
314
Tim Peters1ce3cf72001-10-01 17:58:40 +0000315- The signal module now supports SIGBREAK on Windows, thanks to Steven
316 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
317 action remains to call Win32 ExitProcess(). This can be changed via
318 signal.signal(). For example:
319
320 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
321 # (SIGINT) behavior.
322 import signal
323 signal.signal(signal.SIGBREAK,
324 signal.default_int_handler)
325
326 try:
327 while 1:
328 pass
329 except KeyboardInterrupt:
330 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
331 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
332 # program without the possibility for any Python-level cleanup).
333 print "Clean exit"
334
Tim Petersabf925f2001-09-28 21:53:42 +0000335
Tim Petersb07352e2001-09-08 01:25:47 +0000336What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000337Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000338===========================
339
Guido van Rossum808eea72001-09-25 04:15:41 +0000340Type/class unification and new-style classes
341
342- pydoc and inspect are now aware of new-style classes;
343 e.g. help(list) at the interactive prompt now shows proper
344 documentation for all operations on list objects.
345
346- Applications using Jim Fulton's ExtensionClass module can now safely
347 be used with Python 2.2. In particular, Zope 2.4.1 now works with
348 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
349 examples also work again. It is hoped that Gtk and Boost also work
350 with 2.2a4 and beyond. (If you can confirm this, please write
351 webmaster@python.org; if there are still problems, please open a bug
352 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000353
Tim Peters66c1a522001-09-24 21:17:50 +0000354- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
355 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
356 in the constructed property object. fget, fset and fdel weren't
357 discoverable from Python in 2.2a3. __doc__ is new, and allows to
358 associate a docstring with a property.
359
Guido van Rossum808eea72001-09-25 04:15:41 +0000360- Comparison overloading is now more completely implemented. For
361 example, a str subclass instance can properly be compared to a str
362 instance, and it can properly overload comparison. Ditto for most
363 other built-in object types.
364
365- The repr() of new-style classes has changed; instead of <type
366 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
367 *except* for built-in types, which are still rendered as <type
368 'Foo'> (to avoid upsetting existing code that might parse or
369 otherwise rely on repr() of certain type objects).
370
371- The repr() of new-style objects is now always <Foo object at XXX>;
372 previously, it was sometimes <Foo instance at XXX>.
373
374- For new-style classes, what was previously called __getattr__ is now
375 called __getattribute__. This method, if defined, is called for
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000376 *every* attribute access. A new __getattr__ hook more similar to the
Guido van Rossum808eea72001-09-25 04:15:41 +0000377 one in classic classes is defined which is called only if regular
378 attribute access raises AttributeError; to catch *all* attribute
379 access, you can use __getattribute__ (for new-style classes). If
380 both are defined, __getattribute__ is called first, and if it raises
381 AttributeError, __getattr__ is called.
382
383- The __class__ attribute of new-style objects can be assigned to.
384 The new class must have the same C-level object layout as the old
385 class.
386
387- The builtin file type can be subclassed now. In the usual pattern,
388 "file" is the name of the builtin type, and file() is a new builtin
389 constructor, with the same signature as the builtin open() function.
390 file() is now the preferred way to open a file.
391
392- Previously, __new__ would only see sequential arguments passed to
393 the type in a constructor call; __init__ would see both sequential
394 and keyword arguments. This made no sense whatsoever any more, so
395 now both __new__ and __init__ see all arguments.
396
397- Previously, hash() applied to an instance of a subclass of str or
398 unicode always returned 0. This has been repaired.
399
400- Previously, an operation on an instance of a subclass of an
401 immutable type (int, long, float, complex, tuple, str, unicode),
402 where the subtype didn't override the operation (and so the
403 operation was handled by the builtin type), could return that
404 instance instead a value of the base type. For example, if s was of
405 a str sublass type, s[:] returned s as-is. Now it returns a str
406 with the same value as s.
407
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000408- Provisional support for pickling new-style objects has been added.
409
Guido van Rossum808eea72001-09-25 04:15:41 +0000410Core
411
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000412- file.writelines() now accepts any iterable object producing strings.
413
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000414- PyUnicode_FromEncodedObject() now works very much like
415 PyObject_Str(obj) in that it tries to use __str__/tp_str
416 on the object if the object is not a string or buffer. This
417 makes unicode() behave like str() when applied to non-string/buffer
418 objects.
419
Andrew M. Kuchling51c18162001-10-22 01:47:26 +0000420- PyFile_WriteObject now passes Unicode objects to the file's write
421 method. As a result, all file-like objects which may be the target
Martin v. Löwis2777c022001-09-19 13:47:32 +0000422 of a print statement must support Unicode objects, i.e. they must
423 at least convert them into ASCII strings.
424
Guido van Rossum624c8af2001-09-18 15:21:04 +0000425- Thread scheduling on Solaris should be improved; it is no longer
426 necessary to insert a small sleep at the start of a thread in order
427 to let other runnable threads be scheduled.
428
Tim Petersb07352e2001-09-08 01:25:47 +0000429Library
430
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000431- StringIO.StringIO instances and cStringIO.StringIO instances support
432 read character buffer compatible objects for their .write() methods.
433 These objects are converted to strings and then handled as such
434 by the instances.
435
Barry Warsaw2f600732001-09-24 04:28:10 +0000436- The "email" package has been added. This is basically a port of the
437 mimelib package <http://sf.net/projects/mimelib> with API changes
438 and some implementations updated to use iterators and generators.
439
Tim Peters8a9c2842001-09-22 21:30:22 +0000440- difflib.ndiff() and difflib.Differ.compare() are generators now. This
441 restores the ability of Tools/scripts/ndiff.py to start producing output
442 before the entire comparison is complete.
443
Barry Warsaw58b072d2001-09-22 04:44:21 +0000444- StringIO.StringIO instances and cStringIO.StringIO instances support
445 iteration just like file objects (i.e. their .readline() method is
446 called for each iteration until it returns an empty string).
447
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000448- The codecs module has grown four new helper APIs to access
449 builtin codecs: getencoder(), getdecoder(), getreader(),
450 getwriter().
451
Guido van Rossum624c8af2001-09-18 15:21:04 +0000452- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
453 simplifies writing XML RPC servers.
454
Barry Warsaw647d5e82001-09-28 17:01:02 +0000455- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000456 after interpretation of symbolic links. On non-Unix systems, this
457 is an alias for os.path.abspath().
458
Tim Peters16a77ad2001-09-08 04:00:12 +0000459- operator.indexOf() (PySequence_Index() in the C API) now works with any
460 iterable object.
461
Guido van Rossum624c8af2001-09-18 15:21:04 +0000462- smtplib now supports various authentication and security features of
463 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000464
Guido van Rossum624c8af2001-09-18 15:21:04 +0000465- hmac: a new module implementing keyed hashing for message
466 authentication.
467
468- mimetypes now recognizes more extensions and file types. At the
469 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000470
Guido van Rossum624c8af2001-09-18 15:21:04 +0000471- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000472 Python 2.2 bytecode generation. It has also been promoted from a
473 Tool to a standard library package. (Tools/compiler still exists as
474 a sample driver.)
475
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000476Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000477
Tim Petersb07352e2001-09-08 01:25:47 +0000478Build
479
Guido van Rossum624c8af2001-09-18 15:21:04 +0000480- Large file support (LFS) is now automatic when the platform supports
481 it; no more manual configuration tweaks are needed. On Linux, at
482 least, it's possible to have a system whose C library supports large
483 files but whose kernel doesn't; in this case, large file support is
484 still enabled but doesn't do you any good unless you upgrade your
485 kernel or share your Python executable with another system whose
486 kernel has large file support.
487
488- The configure script now supplies plausible defaults in a
489 cross-compilation environment. This doesn't mean that the supplied
490 values are always correct, or that cross-compilation now works
491 flawlessly -- but it's a first step (and it shuts up most of
492 autoconf's warnings about AC_TRY_RUN).
493
494- The Unix build is now a bit less chatty, courtesy of the parser
495 generator. The build is completely silent (except for errors) when
496 using "make -s", thanks to a -q option to setup.py.
497
Tim Petersb07352e2001-09-08 01:25:47 +0000498C API
499
Guido van Rossum624c8af2001-09-18 15:21:04 +0000500- The "structmember" API now supports some new flag bits to deny read
501 and/or write access to attributes in restricted execution mode.
502
Tim Petersb07352e2001-09-08 01:25:47 +0000503New platforms
504
Guido van Rossum624c8af2001-09-18 15:21:04 +0000505- Compaq's iPAQ handheld, running the "familiar" Linux distribution
506 (http://familiar.handhelds.org).
507
Tim Petersb07352e2001-09-08 01:25:47 +0000508Tests
509
Tim Peters8a9c2842001-09-22 21:30:22 +0000510- The "classic" standard tests, which work by comparing stdout to
511 an expected-output file under Lib/test/output/, no longer stop at
512 the first mismatch. Instead the test is run to completion, and a
513 variant of ndiff-style comparison is used to report all differences.
514 This is much easier to understand than the previous style of reporting.
515
516- The unittest-based standard tests now use regrtest's test_main()
517 convention, instead of running as a side-effect of merely being
518 imported. This allows these tests to be run in more natural and
519 flexible ways as unittests, outside the regrtest framework.
520
521- regrtest.py is much better integrated with unittest and doctest now,
522 especially in regard to reporting errors.
523
Tim Petersb07352e2001-09-08 01:25:47 +0000524Windows
525
Guido van Rossum624c8af2001-09-18 15:21:04 +0000526- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000527 that support it (NTFS under Windows 2000). See "What's New in
528 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000529
Tim Petersb07352e2001-09-08 01:25:47 +0000530
Tim Petersedc99312001-08-22 21:36:50 +0000531What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000532Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000533===========================
534
535Core
536
Tim Peters9fffa3e2001-09-04 05:14:19 +0000537- Conversion of long to float now raises OverflowError if the long is too
538 big to represent as a C double.
539
Tim Peters32f453e2001-09-03 08:35:41 +0000540- The 3-argument builtin pow() no longer allows a third non-None argument
541 if either of the first two arguments is a float, or if both are of
542 integer types and the second argument is negative (in which latter case
543 the arguments are converted to float, so this is really the same
544 restriction).
545
Tim Peters5d2b77c2001-09-03 05:47:38 +0000546- The builtin dir() now returns more information, and sometimes much
547 more, generally naming all attributes of an object, and all attributes
548 reachable from the object via its class, and from its class's base
549 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
550 an empty list. In 2.2a3,
551
552 >>> dir([])
553 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
554 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
555 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
556 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
557 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
558 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
559 'reverse', 'sort']
560
561 dir(module) continues to return only the module's attributes, though.
562
Tim Petersbdee63f2001-09-02 03:40:59 +0000563- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000564 than raising OverflowError. This is a partial implementation of PEP
565 237. You can use -Wdefault::OverflowWarning to enable a warning for
566 this situation, and -Werror::OverflowWarning to revert to the old
567 OverflowError exception.
568
Guido van Rossum61c345f2001-09-04 03:26:15 +0000569- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000570 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000571 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
572 -Qold, meaning the / operator has its classic meaning and no
573 warnings are issued. Using -Qwarn issues a run-time warning about
574 all uses of classic division for int and long arguments; -Qwarnall
575 also warns about classic division for float and complex arguments
576 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
577 new division by default, but only in the __main__ module. You can
578 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
579 __main__ module new division, and warns about classic division
580 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000581
Tim Petersbdee63f2001-09-02 03:40:59 +0000582- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000583 long, float, str, unicode, and tuple. (The types complex, list and
584 dictionary can also be subclassed; this was introduced earlier.)
585 Note that restrictions apply when subclassing immutable built-in
586 types: you can only affect the value of the instance by overloading
587 __new__. You can add mutable attributes, and the subclass instances
588 will have a __dict__ attribute, but you cannot change the "value"
589 (as implemented by the base class) of an immutable subclass instance
590 once it is created.
591
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000592- The dictionary constructor now takes an optional argument, a
593 mapping-like object, and initializes the dictionary from its
594 (key, value) pairs.
595
Tim Petersbdee63f2001-09-02 03:40:59 +0000596- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000597 "cooperative super calls" in a multiple inheritance setting. For an
598 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
599
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000600- A new built-in type, property, has been added. This enables the
601 creation of "properties". These are attributes implemented by
602 getter and setter functions (or only one of these for read-only or
603 write-only attributes), without the need to override __getattr__.
604 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000605
Tim Petersbdee63f2001-09-02 03:40:59 +0000606- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000607 liberalized, to allow leading zeroes. Examples of literals now
608 legal that were SyntaxErrors before:
609
610 00.0 0e3 0100j 07.5 00000000000000000008.
611
Tim Petersbdee63f2001-09-02 03:40:59 +0000612- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000613 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
614
Tim Petersedc99312001-08-22 21:36:50 +0000615Library
616
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000617- telnetlib includes symbolic names for the options, and support for
618 setting an option negotiation callback.
619
Tim Petersa40c7932001-09-05 22:36:56 +0000620- The new C standard no longer requires that math libraries set errno to
621 ERANGE on overflow. For platform libraries that exploit this new
622 freedom, Python's overflow-checking was wholly broken. A new overflow-
623 checking scheme attempts to repair that, but may not be reliable on all
624 platforms (C doesn't seem to provide anything both useful and portable
625 in this area anymore).
626
Martin v. Löwis44f86962001-09-05 13:44:54 +0000627- Asynchronous timeout actions are available through the new class
628 threading.Timer.
629
Tim Peters78526162001-09-05 00:53:45 +0000630- math.log and math.log10 now return sensible results for even huge
631 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
632
Tim Petersbdee63f2001-09-02 03:40:59 +0000633- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000634 currently held. See the docs for the imp module.
635
Tim Petersbdee63f2001-09-02 03:40:59 +0000636- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000637 dumps containing ints written on platforms where Python ints are 8 bytes.
638 When read on a box where Python ints are 4 bytes, such values are
639 converted to Python longs.
640
Tim Petersbdee63f2001-09-02 03:40:59 +0000641- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000642 code objects is no longer allowed. This plugs a security hole.
643
Steve Purcell6091cd62001-09-06 16:05:17 +0000644- unittest.TestResult instances no longer store references to tracebacks
645 generated by test failures. This prevents unexpected dangling references
646 to objects that should be garbage collected between tests.
647
Tim Petersedc99312001-08-22 21:36:50 +0000648Tools
649
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000650- Tools/scripts/fixdiv.py has been added which can be used to fix
651 division operators as per PEP 238.
652
Tim Petersedc99312001-08-22 21:36:50 +0000653Build
654
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000655- If you are an adventurous person using Mac OS X you may want to look at
656 Mac/OSX. There is a Makefile there that will build Python as a real Mac
657 application, which can be used for experimenting with Carbon or Cocoa.
658 Discussion of this on pythonmac-sig, please.
659
Tim Peters7eea37e2001-09-04 22:08:56 +0000660C API
661
662- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000663
Tim Peters9fffa3e2001-09-04 05:14:19 +0000664- Note that PyLong_AsDouble can fail! This has always been true, but no
665 callers checked for it. It's more likely to fail now, because overflow
666 errors are properly detected now. The proper way to check:
667
668 double x = PyLong_AsDouble(some_long_object);
669 if (x == -1.0 && PyErr_Occurred()) {
670 /* The conversion failed. */
671 }
672
Tim Petersbdee63f2001-09-02 03:40:59 +0000673- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000674 compile but will not participate in GC. To upgrade an extension
675 module:
676
677 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000678
Neil Schemenauer4042c692001-08-30 15:38:01 +0000679 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
680 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000681
Neil Schemenauer4042c692001-08-30 15:38:01 +0000682 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
683 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000684
Neil Schemenauer4042c692001-08-30 15:38:01 +0000685 - remove PyGC_HEAD_SIZE from object size calculations
686
687 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
688
Tim Petersbdee63f2001-09-02 03:40:59 +0000689- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000690 These can be used safely to construct string objects from a
691 sprintf-style format string (similar to the format string supported
692 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000693
Tim Petersedc99312001-08-22 21:36:50 +0000694New platforms
695
Tim Petersb7da0902001-09-02 23:01:43 +0000696- Stephen Hansen contributed patches sufficient to get a clean compile
697 under Borland C (Windows), but he reports problems running it and ran
698 out of time to complete the port. Volunteers? Expect a MemoryError
699 when importing the types module; this is probably shallow, and
700 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000701
Tim Petersedc99312001-08-22 21:36:50 +0000702Tests
703
704Windows
705
Tim Peters6e13a562001-09-06 00:32:15 +0000706- Large file support is now enabled on Win32 platforms as well as on
707 Win64. This means that, for example, you can use f.tell() and f.seek()
708 to manipulate files larger than 2 gigabytes (provided you have enough
709 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000710 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
711 filesize limit, and large file support makes no difference there.
712 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
713 NTFS has no practical limit on file size, and files of any size can be
714 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000715
Tim Petersbdee63f2001-09-02 03:40:59 +0000716- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000717 points to command.com (patch from Brian Quinlan).
718
Tim Petersedc99312001-08-22 21:36:50 +0000719
Tim Peters20f51a72001-07-21 02:31:40 +0000720What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000721Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000722===========================
723
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000724Build
725
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000726- Tim Peters developed a brand new Windows installer using Wise 8.1,
727 generously donated to us by Wise Solutions.
728
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000729- configure supports a new option --enable-unicode, with the values
730 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
731 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000732
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000733- A new configure option --enable-framework builds a Mac OS X framework,
734 which "make frameworkinstall" will install. This provides a starting
735 point for more mac-like functionality, join pythonmac-sig@python.org
736 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000737
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000738- The NeXT platform is no longer supported.
739
740- The `new' module is now statically linked.
741
Tim Peters0afb6092001-08-15 06:06:44 +0000742Tools
743
744- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000745 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000746 the module docstring for details.
747
Tim Peters20f51a72001-07-21 02:31:40 +0000748Tests
749
Tim Peters5e824c32001-08-12 22:25:01 +0000750- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000751 platforms, allowing to give clearer test result output. regrtest
752 also has optional --use/-u switch to run normally disabled tests
753 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000754
Tim Peters20f51a72001-07-21 02:31:40 +0000755- Several new tests in the standard test suite, with special thanks to
756 Nick Mathewson.
757
758Core
759
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000760- The floor division operator // has been added as outlined in PEP
761 238. The / operator still provides classic division (and will until
762 Python 3.0) unless "from __future__ import division" is included, in
763 which case the / operator will provide true division. The operator
764 module provides truediv() and floordiv() functions. Augmented
765 assignment variants are included, as are the equivalent overloadable
766 methods and C API methods. See the PEP for a full discussion:
767 <http://python.sf.net/peps/pep-0238.html>
768
Tim Peters6cd6a822001-08-17 22:11:27 +0000769- Future statements are now effective in simulated interactive shells
770 (like IDLE). This should "just work" by magic, but read Michael
771 Hudson's "Future statements in simulated shells" PEP 264 for full
772 details: <http://python.sf.net/peps/pep-0264.html>.
773
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000774- The type/class unification (PEP 252-253) was integrated into the
775 trunk and is not so tentative any more (the exact specification of
776 some features is still tentative). A lot of work has done on fixing
777 bugs and adding robustness and features (performance still has to
778 come a long way).
779
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000780- Warnings about a mismatch in the Python API during extension import
781 now use the Python warning framework (which makes it possible to
782 write filters for these warnings).
783
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000784- A function's __dict__ (aka func_dict) will now always be a
785 dictionary. It used to be possible to delete it or set it to None,
786 but now both actions raise TypeErrors. It is still legal to set it
787 to a dictionary object. Getting func.__dict__ before any attributes
788 have been assigned now returns an empty dictionary instead of None.
789
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000790- A new command line option, -E, was added which disables the use of
791 all environment variables, or at least those that are specifically
792 significant to Python. Usually those have a name starting with
793 "PYTHON". This was used to fix a problem where the tests fail if
794 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
795 older distribution.
796
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000797Library
798
Tim Peters5e824c32001-08-12 22:25:01 +0000799- New class Differ and new functions ndiff() and restore() in difflib.py.
800 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000801 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000802
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000803- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
804 value using the minimal quoting required for the value; more
805 reliable than using xml.sax.saxutils.escape() for attribute values.
806
807- Readline completion support for cmd.Cmd was added.
808
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000809- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
810
811- Added function threading.BoundedSemaphore()
812
813- Added Ka-Ping Yee's cgitb.py module.
814
815- The `new' module now exposes the CO_xxx flags.
816
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000817New platforms
818
819C API
820
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000821- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
822 which provide a cross-platform implementations for the
823 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
824 the standard sprintf() and vsprintf() C lib APIs, these versions
825 apply bounds checking on the used buffer which enhances protection
826 against buffer overruns.
827
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000828- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000829 and extensions using different Unicode widths is rendered next to
830 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000831 will result in an ImportError. Unicode extensions writers must make
832 sure to check the Unicode width compatibility in their extensions by
833 using at least one of the mangled Unicode APIs in the extension.
834
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000835- Two new flags METH_NOARGS and METH_O are available in method definition
836 tables to simplify implementation of methods with no arguments and a
837 single untyped argument. Calling such methods is more efficient than
838 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
839 deprecated.
840
Tim Petersc1731372001-08-04 08:12:36 +0000841Windows
842
843- "import module" now compiles module.pyw if it exists and nothing else
844 relevant is found.
845
Tim Peters20f51a72001-07-21 02:31:40 +0000846
Guido van Rossum55a78992001-07-17 17:22:32 +0000847What's New in Python 2.2a1?
Barry Warsawd970fe42001-10-25 21:53:30 +0000848Release date: 18-Jul-2001
Tim Petersf553f892001-05-01 20:45:31 +0000849===========================
850
851Core
Tim Petersa814db52001-05-14 07:05:58 +0000852
Tim Peters6d6c1a32001-08-02 04:15:00 +0000853- TENTATIVELY, a large amount of code implementing much of what's
854 described in PEP 252 (Making Types Look More Like Classes) and PEP
855 253 (Subtyping Built-in Types) was added. This will be released
856 with Python 2.2a1. Documentation will be provided separately
857 through http://www.python.org/2.2/. The purpose of releasing this
858 with Python 2.2a1 is to test backwards compatibility. It is
859 possible, though not likely, that a decision is made not to release
860 this code as part of 2.2 final, if any serious backwards
861 incompapatibilities are found during alpha testing that cannot be
862 repaired.
863
Guido van Rossum55a78992001-07-17 17:22:32 +0000864- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000865 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000866 more 'yield' statements. See PEP 255. Since this adds a new
867 keyword to the language, this feature must be enabled by including a
868 future statement: "from __future__ import generators" (see PEP 236).
869 Generators will become a standard feature in a future release
870 (probably 2.3). Without this future statement, 'yield' remains an
871 ordinary identifier, but a warning is issued each time it is used.
872 (These warnings currently don't conform to the warnings framework of
873 PEP 230; we intend to fix this in 2.2a2.)
874
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000875- The UTF-16 codec was modified to be more RFC compliant. It will now
876 only remove BOM characters at the start of the string and then
877 only if running in native mode (UTF-16-LE and -BE won't remove a
878 leading BMO character).
879
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000880- Strings now have a new method .decode() to complement the already
881 existing .encode() method. These two methods provide direct access
882 to the corresponding decoders and encoders of the registered codecs.
883
884 To enhance the usability of the .encode() method, the special
885 casing of Unicode object return values was dropped (Unicode objects
886 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000887
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000888 Both methods will now return whatever the codec in charge of the
889 requested encoding returns as object, e.g. Unicode codecs will
890 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
891 will return u"äöü"). This enables codec writer to create codecs
892 for various simple to use conversions.
893
894 New codecs were added to demonstrate these new features (the .encode()
895 and .decode() columns indicate the type of the returned objects):
896
897 Name | .encode() | .decode() | Description
898 ----------------------------------------------------------------------
899 uu | string | string | UU codec (e.g. for email)
900 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000901 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000902 zlib | string | string | zlib compression
903 hex | string | string | 2-byte hex codec
904 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
905
Mark Hammond2a0af792001-05-14 03:09:36 +0000906- Some operating systems now support the concept of a default Unicode
907 encoding for file system operations. Notably, Windows supports 'mbcs'
908 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000909 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000910 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000911
912 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000913 functions that return filenames (such as os.listdir()) to return Python
914 string objects pre-encoded using the default file system encoding for
915 the platform. As this encoding is likely to be different from Python's
916 default encoding, converting this name to a Unicode object before passing
917 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000918 would attempt to use its default encoding (generally ASCII) rather than
919 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000920
Tim Petersa814db52001-05-14 07:05:58 +0000921 In general, this change simply removes surprises when working with
922 Unicode and the file system, making these operations work as you expect,
923 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000924 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000925
Tim Peters61dff2b2001-05-08 15:43:37 +0000926- Float (and complex) literals in source code were evaluated to full
927 precision only when running from a .py file; the same code loaded from a
928 .pyc (or .pyo) file could suffer numeric differences starting at about the
929 12th significant decimal digit. For example, on a machine with IEEE-754
930 floating arithmetic,
931
932 x = 9007199254740992.0
933 print long(x)
934
935 printed 9007199254740992 if run directly from .py, but 9007199254740000
936 if from a compiled (.pyc or .pyo) file. This was due to marshal using
937 str(float) instead of repr(float) when building code objects. marshal
938 now uses repr(float) instead, which should reproduce floats to full
939 machine precision (assuming the platform C float<->string I/O conversion
940 functions are of good quality).
941
942 This may cause floating-point results to change in some cases, and
943 usually for the better, but may also cause numerically unstable
944 algorithms to break.
945
Tim Peters2f228e72001-05-13 00:19:31 +0000946- The implementation of dicts suffers fewer collisions, which has speed
947 benefits. However, the order in which dict entries appear in dict.keys(),
948 dict.values() and dict.items() may differ from previous releases for a
949 given dict. Nothing is defined about this order, so no program should
950 rely on it. Nevertheless, it's easy to write test cases that rely on the
951 order by accident, typically because of printing the str() or repr() of a
952 dict to an "expected results" file. See Lib/test/test_support.py's new
953 sortdict(dict) function for a simple way to display a dict in sorted
954 order.
955
Tim Peters7a3bfc32001-06-12 01:22:22 +0000956- Many other small changes to dicts were made, resulting in faster
957 operation along the most common code paths.
958
Guido van Rossum10315822001-05-01 20:54:30 +0000959- Dictionary objects now support the "in" operator: "x in dict" means
960 the same as dict.has_key(x).
961
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000962- The update() method of dictionaries now accepts generic mapping
963 objects. Specifically the argument object must support the .keys()
964 and __getitem__() methods. This allows you to say, for example,
965 {}.update(UserDict())
966
Guido van Rossum10315822001-05-01 20:54:30 +0000967- Iterators were added; this is a generalized way of providing values
968 to a for loop. See PEP 234. There's a new built-in function iter()
969 to return an iterator. There's a new protocol to get the next value
970 from an iterator using the next() method (in Python) or the
971 tp_iternext slot (in C). There's a new protocol to get iterators
972 using the __iter__() method (in Python) or the tp_iter slot (in C).
973 Iterating (i.e. a for loop) over a dictionary generates its keys.
974 Iterating over a file generates its lines.
975
Tim Petersf553f892001-05-01 20:45:31 +0000976- The following functions were generalized to work nicely with iterator
977 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000978 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000979 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
980 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000981 join() method of strings
982 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000983 'x in y' and 'x not in y' (PySequence_Contains() in C API)
984 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000985 right-hand side of assignment statements with multiple targets, such as
986 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000987
Tim Petersd85e1022001-05-11 21:51:48 +0000988- Accessing module attributes is significantly faster (for example,
989 random.random or os.path or yourPythonModule.yourAttribute).
990
Tim Peterse63415e2001-05-08 04:38:29 +0000991- Comparing dictionary objects via == and != is faster, and now works even
992 if the keys and values don't support comparisons other than ==.
993
Tim Peters95bf9392001-05-10 08:32:44 +0000994- Comparing dictionaries in ways other than == and != is slower: there were
995 insecurities in the dict comparison implementation that could cause Python
996 to crash if the element comparison routines for the dict keys and/or
997 values mutated the dicts. Making the code bulletproof slowed it down.
998
Tim Peterseb28ef22001-06-02 05:27:19 +0000999- Collisions in dicts are resolved via a new approach, which can help
1000 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +00001001 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +00001002 faster now. Thanks to Christian Tismer for pointing out the cause and
1003 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +00001004
Tim Peters52e155e2001-06-16 05:42:57 +00001005- repr() is much faster for large containers (dict, list, tuple).
1006
1007
Tim Petersa814db52001-05-14 07:05:58 +00001008Library
1009
Fred Drake960fdf92001-07-20 18:38:26 +00001010- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
1011 were added to the string module. These a locale-indenpendent
1012 constants, unlike letters, lowercase, and uppercase. These are now
1013 use in appropriate locations in the standard library.
1014
Martin v. Löwisf0473d52001-07-18 16:17:16 +00001015- The flags used in dlopen calls can now be configured using
1016 sys.setdlopenflags and queried using sys.getdlopenflags.
1017
Guido van Rossumc7e4aca2001-07-12 11:54:37 +00001018- Fredrik Lundh's xmlrpclib is now a standard library module. This
1019 provides full client-side XML-RPC support. In addition,
1020 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
1021 one asyncore-based). Thanks to Eric Raymond for the documentation.
1022
Guido van Rossum643d3912001-07-05 14:46:25 +00001023- The xrange() object is simplified: it no longer supports slicing,
1024 repetition, comparisons, efficient 'in' checking, the tolist()
1025 method, or the start, stop and step attributes. See PEP 260.
1026
Martin v. Löwisebf94db2001-06-06 06:25:40 +00001027- A new function fnmatch.filter to filter lists of file names was added.
1028
Barry Warsawffd674d2001-05-22 16:00:10 +00001029- calendar.py uses month and day names based on the current locale.
1030
Guido van Rossum2e0a6542001-05-15 02:14:44 +00001031- strop is now *really* obsolete (this was announced before with 1.6),
1032 and issues DeprecationWarning when used (except for the four items
1033 that are still imported into string.py).
1034
Tim Petersa814db52001-05-14 07:05:58 +00001035- Cookie.py now sorts key+value pairs by key in output strings.
1036
1037- pprint.isrecursive(object) didn't correctly identify recursive objects.
1038 Now it does.
1039
Tim Peters95b3f782001-05-14 18:39:41 +00001040- pprint functions now much faster for large containers (tuple, list, dict).
1041
Tim Peters7b9542a2001-06-10 23:40:19 +00001042- New 'q' and 'Q' format codes in the struct module, corresponding to C
1043 types "long long" and "unsigned long long" (on Windows, __int64). In
1044 native mode, these can be used only when the platform C compiler supports
1045 these types (when HAVE_LONG_LONG is #define'd by the Python config
1046 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +00001047 In standard mode, 'q' and 'Q' are supported on all platforms, and are
1048 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +00001049
Guido van Rossum83213cc2001-06-12 16:48:52 +00001050- The site module installs a new built-in function 'help' that invokes
1051 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
1052 it displays a message reminding the user to use 'help()' or
1053 'help(object)'.
1054
Tim Petersa814db52001-05-14 07:05:58 +00001055Tests
1056
1057- New test_mutants.py runs dict comparisons where the key and value
1058 comparison operators mutute the dicts randomly during comparison. This
1059 rapidly causes Python to crash under earlier releases (not for the faint
1060 of heart: it can also cause Win9x to freeze or reboot!).
1061
1062- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +00001063 pprint.isreadable() return sensible results. Also verifies that simple
1064 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +00001065
Tim Peters4324aa32001-05-28 22:30:08 +00001066C API
1067
1068- Removed the unused last_is_sticky argument from the internal
1069 _PyTuple_Resize(). If this affects you, you were cheating.
1070
1071
Guido van Rossum55a78992001-07-17 17:22:32 +00001072======================================================================
1073
1074
Guido van Rossumffe13be2001-04-16 18:46:45 +00001075What's New in Python 2.1 (final)?
1076=================================
1077
1078We only changed a few things since the last release candidate, all in
1079Python library code:
1080
1081- A bug in the locale module was fixed that affected locales which
1082 define no grouping for numeric formatting.
1083
1084- A few bugs in the weakref module's implementations of weak
1085 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
1086 and the test suite was updated to check for these bugs.
1087
1088- An old bug in the os.path.walk() function (introduced in Python
1089 2.0!) was fixed: a non-existent file would cause an exception
1090 instead of being ignored.
1091
1092- Fixed a few bugs in the new symtable module found by Neil Norwitz's
1093 PyChecker.
1094
1095
Guido van Rossum5b08f132001-04-16 02:05:23 +00001096What's New in Python 2.1c2?
1097===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +00001098
Guido van Rossum5b08f132001-04-16 02:05:23 +00001099A flurry of small changes, and one showstopper fixed in the nick of
1100time made it necessary to release another release candidate. The list
1101here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +00001102
Guido van Rossum5b08f132001-04-16 02:05:23 +00001103Core
Guido van Rossum4fb60362001-04-13 00:46:14 +00001104
Guido van Rossum5b08f132001-04-16 02:05:23 +00001105- Tim discovered a nasty bug in the dictionary code, caused by
1106 PyDict_Next() calling dict_resize(), and the GC code's use of
1107 PyDict_Next() violating an assumption in dict_items(). This was
1108 fixed with considerable amounts of band-aid, but the net effect is a
1109 saner and more robust implementation.
1110
1111- Made a bunch of symbols static that were accidentally global.
1112
1113Build and Ports
1114
1115- The setup.py script didn't check for a new enough version of zlib
1116 (1.1.3 is needed). Now it does.
1117
1118- Changed "make clean" target to also remove shared libraries.
1119
1120- Added a more general warning about the SGI Irix optimizer to README.
1121
1122Library
1123
1124- Fix a bug in urllib.basejoin("http://host", "../file.html") which
1125 omitted the slash between host and file.html.
1126
1127- The mailbox module's _Mailbox class contained a completely broken
1128 and undocumented seek() method. Ripped it out.
1129
1130- Fixed a bunch of typos in various library modules (urllib2, smtpd,
1131 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
1132
1133- Fixed a few last-minute bugs in unittest.
1134
1135Extensions
1136
1137- Reverted the patch to the OpenSSL code in socketmodule.c to support
1138 RAND_status() and the EGD, and the subsequent patch that tried to
1139 fix it for pre-0.9.5 versions; the problem with the patch is that on
1140 some systems it issues a warning whenever socket is imported, and
1141 that's unacceptable.
1142
1143Tests
1144
1145- Fixed the pickle tests to work with "import test.test_pickle".
1146
1147- Tweaked test_locale.py to actually run the test Windows.
1148
1149- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
1150 not "wb" (which is not a valid mode at all).
1151
1152- Fix pstats browser crashes. Import readline if it exists to make
1153 the user interface nicer.
1154
1155- Add "import thread" to the top of test modules that import the
1156 threading module (test_asynchat and test_threadedtempfile). This
1157 prevents test failures caused by a broken threading module resulting
1158 from a previously caught failed import.
1159
1160- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
1161 needed on some platforms (e.g. Solaris 8) when the tests are run
1162 twice in succession.
1163
1164- Skip rather than fail test_sunaudiodev if no audio device is found.
1165
1166
1167What's New in Python 2.1c1?
1168===========================
1169
1170This list was significantly updated when 2.1c2 was released; the 2.1c1
1171release didn't mention most changes that were actually part of 2.1c1:
1172
1173Legal
1174
1175- Copyright was assigned to the Python Software Foundation (PSF) and a
1176 PSF license (very similar to the CNRI license) was added.
1177
1178- The CNRI copyright notice was updated to include 2001.
1179
1180Core
Barry Warsaw11e89c72001-04-11 20:37:57 +00001181
Guido van Rossumc9932722001-04-12 02:31:27 +00001182- After a public outcry, assignment to __debug__ is no longer illegal;
1183 instead, a warning is issued. It will become illegal in 2.2.
1184
Guido van Rossum5b08f132001-04-16 02:05:23 +00001185- Fixed a core dump with "%#x" % 0, and changed the semantics so that
1186 "%#x" now always prepends "0x", even if the value is zero.
1187
1188- Fixed some nits in the bytecode compiler.
1189
1190- Fixed core dumps when calling certain kinds of non-functions.
1191
1192- Fixed various core dumps caused by reference count bugs.
1193
1194Build and Ports
1195
1196- Use INSTALL_SCRIPT to install script files.
1197
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001198- New port: SCO Unixware 7, by Billy G. Allie.
1199
Guido van Rossum5b08f132001-04-16 02:05:23 +00001200- Updated RISCOS port.
1201
1202- Updated BeOS port and notes.
1203
1204- Various other porting problems resolved.
1205
1206Library
1207
1208- The TERMIOS and SOCKET modules are now truly obsolete and
1209 unnecessary. Their symbols are incorporated in the termios and
1210 socket modules.
1211
1212- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1213 better tests for pickling.
1214
1215- threading: make Condition.wait() robust against KeyboardInterrupt.
1216
1217- zipfile: add support to zipfile to support opening an archive
1218 represented by an open file rather than a file name. Fix bug where
1219 the archive was not properly closed. Fixed a bug in this bugfix
1220 where flush() was called for a read-only file.
1221
1222- imputil: added an uninstall() method to the ImportManager.
1223
1224- Canvas: fixed bugs in lower() and tkraise() methods.
1225
1226- SocketServer: API change (added overridable close_request() method)
1227 so that the TCP server can explicitly close the request.
1228
1229- pstats: Eric Raymond added a simple interactive statistics browser,
1230 invoked when the module is run as a script.
1231
1232- locale: fixed a problem in format().
1233
1234- webbrowser: made it work when the BROWSER environment variable has a
1235 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1236 KDE 2. Fixed some other nits.
1237
1238- unittest: changes to allow using a different exception than
1239 AssertionError, and added a few more function aliases. Some other
1240 small changes.
1241
1242- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1243
1244- asynchat: fixed a critical bug in asynchat that slipped through the
1245 2.1b2 release. Fixed another rare bug.
1246
1247- Fix some unqualified except: clauses (always a bad code example).
1248
1249XML
1250
1251- pyexpat: new API get_version_string().
1252
1253- Fixed some minidom bugs.
1254
1255Extensions
1256
1257- Fixed a core dump in _weakref. Removed the weakref.mapping()
1258 function (it adds nothing to the API).
1259
1260- Rationalized the use of header files in the readline module, to make
1261 it compile (albeit with some warnings) with the very recent readline
1262 4.2, without breaking for earlier versions.
1263
1264- Hopefully fixed a buffering problem in linuxaudiodev.
1265
1266- Attempted a fix to make the OpenSSL support in the socket module
1267 work again with pre-0.9.5 versions of OpenSSL.
1268
1269Tests
1270
1271- Added a test case for asynchat and asyncore.
1272
1273- Removed coupling between tests where one test failing could break
1274 another.
1275
1276Tools
1277
1278- Ping added an interactive help browser to pydoc, fixed some nits
1279 in the rest of the pydoc code, and added some features to his
1280 inspect module.
1281
1282- An updated python-mode.el version 4.1 which integrates Ken
1283 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1284 much nicer in XEmacs and Emacs. When stepping through your program
1285 with pdb, in either the shell window or the *Python* window, the
1286 source file and line will be tracked by an arrow. Very cool!
1287
1288- IDLE: syntax warnings in interactive mode are changed into errors.
1289
1290- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001291 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001292
1293- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001294
Barry Warsaw11e89c72001-04-11 20:37:57 +00001295
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001296What's New in Python 2.1 beta 2?
1297================================
1298
Guido van Rossum053ae352001-03-22 14:17:21 +00001299(Unlisted are many fixed bugs, more documentation, etc.)
1300
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001301Core language, builtins, and interpreter
1302
Guido van Rossum053ae352001-03-22 14:17:21 +00001303- The nested scopes work (enabled by "from __future__ import
1304 nested_scopes") is completed; in particular, the future now extends
1305 into code executed through exec, eval() and execfile(), and into the
1306 interactive interpreter.
1307
1308- When calling a base class method (e.g. BaseClass.__init__(self)),
1309 this is now allowed even if self is not strictly spoken a class
1310 instance (e.g. when using metaclasses or the Don Beaudry hook).
1311
1312- Slice objects are now comparable but not hashable; this prevents
1313 dict[:] from being accepted but meaningless.
1314
1315- Complex division is now calculated using less braindead algorithms.
1316 This doesn't change semantics except it's more likely to give useful
1317 results in extreme cases. Complex repr() now uses full precision
1318 like float repr().
1319
1320- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1321
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001322- It is illegal to assign to the name __debug__, which is set when the
1323 interpreter starts. It is effectively a compile-time constant.
1324
1325- A warning will be issued if a global statement for a variable
1326 follows a use or assignment of that variable.
1327
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001328Standard library
1329
Guido van Rossum053ae352001-03-22 14:17:21 +00001330- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1331 inspired by JUnit), is now part of the standard library. You now
1332 have a choice of two testing frameworks: unittest requires you to
1333 write testcases as separate code, doctest gathers them from
1334 docstrings. Both approaches have their advantages and
1335 disadvantages.
1336
1337- A new module Tix was added, which wraps the Tix extension library
1338 for Tk. With that module, it is not necessary to statically link
1339 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1340 require" command. See Demo/tix/.
1341
1342- tzparse.py is now obsolete.
1343
1344- In gzip.py, the seek() and tell() methods are removed -- they were
1345 non-functional anyway, and it's better if callers can test for their
1346 existence with hasattr().
1347
1348Python/C API
1349
1350- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1351 that's already in the dictionary during a PyDict_Next() iteration.
1352 This used to fail occasionally when a dictionary resize operation
1353 could be triggered that would rehash all the keys. All other
1354 modifications to the dictionary are still off-limits during a
1355 PyDict_Next() iteration!
1356
1357- New extended APIs related to passing compiler variables around.
1358
1359- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1360 implement isinstance() and issubclass().
1361
1362- Py_BuildValue() now has a "D" conversion to create a Python complex
1363 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001364
Fred Drake4e262a92001-03-22 18:26:47 +00001365- Extensions types which support weak references must now set the
1366 field allocated for the weak reference machinery to NULL themselves;
1367 this is done to avoid the cost of checking each object for having a
1368 weakly referencable type in PyObject_INIT(), since most types are
1369 not weakly referencable.
1370
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001371- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1372 free variables and cell variables to and from the frame's f_locals.
1373
1374- Variants of several functions defined in pythonrun.h have been added
1375 to support the nested_scopes future statement. The variants all end
1376 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1377 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1378 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001379 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001380
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001381Distutils
1382
1383- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1384 into the release tree.
1385
Tim Peters0e57abf2001-05-02 07:39:38 +00001386- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001387 (an uninstaller, more customization of the installer's display)
1388
1389- from Jack Jansen: added Mac-specific code to generate a dialog for
1390 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001391 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001392 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001393
1394- added 'platforms' and 'keywords' to the set of metadata that can be
1395 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001396
1397- applied patches from Jason Tishler to make the compiler class work with
1398 Cygwin.
1399
1400
Tim Peters2fe289a2001-03-01 22:19:38 +00001401What's New in Python 2.1 beta 1?
1402================================
Tim Petersd66595f2001-02-04 03:09:53 +00001403
1404Core language, builtins, and interpreter
1405
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001406- Following an outcry from the community about the amount of code
1407 broken by the nested scopes feature introduced in 2.1a2, we decided
1408 to make this feature optional, and to wait until Python 2.2 (or at
1409 least 6 months) to make it standard. The option can be enabled on a
1410 per-module basis by adding "from __future__ import nested_scopes" at
1411 the beginning of a module (before any other statements, but after
1412 comments and an optional docstring). See PEP 236 (Back to the
1413 __future__) for a description of the __future__ statement. PEP 227
1414 (Statically Nested Scopes) has been updated to reflect this change,
1415 and to clarify the semantics in a number of endcases.
1416
1417- The nested scopes code, when enabled, has been hardened, and most
1418 bugs and memory leaks in it have been fixed.
1419
1420- Compile-time warnings are now generated for a number of conditions
1421 that will break or change in meaning when nested scopes are enabled:
1422
1423 - Using "from...import *" or "exec" without in-clause in a function
1424 scope that also defines a lambda or nested function with one or
1425 more free (non-local) variables. The presence of the import* or
1426 bare exec makes it impossible for the compiler to determine the
1427 exact set of local variables in the outer scope, which makes it
1428 impossible to determine the bindings for free variables in the
1429 inner scope. To avoid the warning about import *, change it into
1430 an import of explicitly name object, or move the import* statement
1431 to the global scope; to avoid the warning about bare exec, use
1432 exec...in... (a good idea anyway -- there's a possibility that
1433 bare exec will be deprecated in the future).
1434
1435 - Use of a global variable in a nested scope with the same name as a
1436 local variable in a surrounding scope. This will change in
1437 meaning with nested scopes: the name in the inner scope will
1438 reference the variable in the outer scope rather than the global
1439 of the same name. To avoid the warning, either rename the outer
1440 variable, or use a global statement in the inner function.
1441
Neil Schemenauera35c6882001-02-27 04:45:05 +00001442- An optional object allocator has been included. This allocator is
1443 optimized for Python objects and should be faster and use less memory
1444 than the standard system allocator. It is not enabled by default
1445 because of possible thread safety problems. The allocator is only
1446 protected by the Python interpreter lock and it is possible that some
1447 extension modules require a thread safe allocator. The object
1448 allocator can be enabled by providing the "--with-pymalloc" option to
1449 configure.
1450
Tim Petersd66595f2001-02-04 03:09:53 +00001451Standard library
1452
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001453- pyexpat now detects the expat version if expat.h defines it. A
1454 number of additional handlers are provided, which are only available
1455 since expat 1.95. In addition, the methods SetParamEntityParsing and
1456 GetInputContext of Parser objects are available with 1.95.x
1457 only. Parser objects now provide the ordered_attributes and
1458 specified_attributes attributes. A new module expat.model was added,
1459 which offers a number of additional constants if 1.95.x is used.
1460
1461- xml.dom offers the new functions registerDOMImplementation and
1462 getDOMImplementation.
1463
1464- xml.dom.minidom offers a toprettyxml method. A number of DOM
1465 conformance issues have been resolved. In particular, Element now
1466 has an hasAttributes method, and the handling of namespaces was
1467 improved.
1468
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001469- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1470 getting information about live Python code, and pydoc.py, a module
1471 for interactively converting docstrings to HTML or text.
1472 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001473 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001474 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1475 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001476
Tim Peters1eff7962001-03-01 02:31:33 +00001477- New library module difflib.py, primarily packaging the SequenceMatcher
1478 class at the heart of the popular ndiff.py file-comparison tool.
1479
1480- doctest.py (a framework for verifying Python code examples in docstrings)
1481 is now part of the std library.
1482
Tim Petersd66595f2001-02-04 03:09:53 +00001483Windows changes
1484
Guido van Rossume3955a82001-03-02 14:05:59 +00001485- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1486 small GUI that lets you browse the module docstrings using your
1487 default web browser.
1488
Tim Peters1eff7962001-03-01 02:31:33 +00001489- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1490 Platforms) is implemented. See
1491
1492 http://python.sourceforge.net/peps/pep-0235.html
1493
1494 for full details, especially the "Current Lower-Left Semantics" section.
1495 The new Windows import rules are simpler than before:
1496
1497 A. If the PYTHONCASEOK environment variable exists, same as
1498 before: silently accept the first case-insensitive match of any
1499 kind; raise ImportError if none found.
1500
1501 B. Else search sys.path for the first case-sensitive match; raise
1502 ImportError if none found.
1503
1504 The same rules have been implented on other platforms with case-
1505 insensitive but case-preserving filesystems too (including Cygwin, and
1506 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001507
Tim Peters25a9ce32001-02-19 07:06:36 +00001508- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1509 what it's supposed to do (and does do under NT and 2000) via direct
1510 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001511 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001512 all Win9x systems before.
1513
Tim Peters1eff7962001-03-01 02:31:33 +00001514- Build: Subproject _test (effectively) renamed to _testcapi.
1515
Tim Peters2fe289a2001-03-01 22:19:38 +00001516New platforms
1517
1518- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1519 Thanks to Steven Majewski!
1520
1521- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1522 Tishler!
1523
Guido van Rossum9089b272001-03-02 06:49:50 +00001524- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1525 Schwertberger! See RISCOS/README for more information -- it seems
1526 that because of the bizarre filename conventions on RISCOS, no port
Guido van Rossum49192142001-10-24 20:51:44 +00001527 to that platform is easy.
Guido van Rossum9089b272001-03-02 06:49:50 +00001528
Tim Peters25a9ce32001-02-19 07:06:36 +00001529
Tim Petersd7b5e882001-01-25 03:36:26 +00001530What's New in Python 2.1 alpha 2?
1531=================================
Tim Peters40ead762001-01-27 05:35:26 +00001532
Tim Petersd7b5e882001-01-25 03:36:26 +00001533Core language, builtins, and interpreter
1534
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001535- Scopes nest. If a name is used in a function or class, but is not
1536 local, the definition in the nearest enclosing function scope will
1537 be used. One consequence of this change is that lambda statements
1538 could reference variables in the namespaces where the lambda is
1539 defined. In some unusual cases, this change will break code.
1540
1541 In all previous version of Python, names were resolved in exactly
1542 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001543 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001544 function A is defined within a function B, the names bound in B are
1545 not visible in A. The new rules make names bound in B visible in A,
1546 unless A contains a name binding that hides the binding in B.
1547
1548 Section 4.1 of the reference manual describes the new scoping rules
1549 in detail. The test script in Lib/test/test_scope.py demonstrates
1550 some of the effects of the change.
1551
1552 The new rules will cause existing code to break if it defines nested
1553 functions where an outer function has local variables with the same
1554 name as globals or builtins used by the inner function. Example:
1555
1556 def munge(str):
1557 def helper(x):
1558 return str(x)
1559 if type(str) != type(''):
1560 str = helper(str)
1561 return str.strip()
1562
1563 Under the old rules, the name str in helper() is bound to the
1564 builtin function str(). Under the new rules, it will be bound to
1565 the argument named str and an error will occur when helper() is
1566 called.
1567
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001568- The compiler will report a SyntaxError if "from ... import *" occurs
1569 in a function or class scope. The language reference has documented
1570 that this case is illegal, but the compiler never checked for it.
1571 The recent introduction of nested scope makes the meaning of this
1572 form of name binding ambiguous. In a future release, the compiler
1573 may allow this form when there is no possibility of ambiguity.
1574
Tim Peters40ead762001-01-27 05:35:26 +00001575- repr(string) is easier to read, now using hex escapes instead of octal,
1576 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1577
1578 >>> "\texample \r\n" + chr(0) + chr(255)
1579 '\texample \r\n\x00\xff' # in 2.1
1580 '\011example \015\012\000\377' # in 2.0
1581
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001582- Functions are now compared and hashed by identity, not by value, since
1583 the func_code attribute is writable.
1584
Fred Drakefb9d7122001-02-01 20:00:40 +00001585- Weak references (PEP 205) have been added. This involves a few
1586 changes in the core, an extension module (_weakref), and a Python
1587 module (weakref). The weakref module is the public interface. It
1588 includes support for "explicit" weak references, proxy objects, and
1589 mappings with weakly held values.
1590
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001591- A 'continue' statement can now appear in a try block within the body
1592 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001593 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001594
Tim Petersd7b5e882001-01-25 03:36:26 +00001595Standard library
1596
Barry Warsaw30dbd142001-01-31 22:14:01 +00001597- mailbox.py now has a new class, PortableUnixMailbox which is
1598 identical to UnixMailbox but uses a more portable scheme for
1599 determining From_ separators. Also, the constructors for all the
1600 classes in this module have a new optional `factory' argument, which
1601 is a callable used when new message classes must be instantiated by
1602 the next() method.
1603
Tim Petersd7b5e882001-01-25 03:36:26 +00001604- random.py is now self-contained, and offers all the functionality of
1605 the now-deprecated whrandom.py. See the docs for details. random.py
1606 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001607 and restoring the internal state of the generator; and jumpahead(n),
1608 for quickly forcing the internal state to be the same as if n calls to
1609 random() had been made. The latter is particularly useful for multi-
1610 threaded programs, creating one instance of the random.Random() class for
1611 each thread, then using .jumpahead() to force each instance to use a
1612 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001613
Tim Peters0de88fc2001-02-01 04:59:18 +00001614- random.py's seed() function is new. For bit-for-bit compatibility with
1615 prior releases, use the whseed function instead. The new seed function
1616 addresses two problems: (1) The old function couldn't produce more than
1617 about 2**24 distinct internal states; the new one about 2**45 (the best
1618 that can be done in the Wichmann-Hill generator). (2) The old function
1619 sometimes produced identical internal states when passed distinct
1620 integers, and there was no simple way to predict when that would happen;
1621 the new one guarantees to produce distinct internal states for all
1622 arguments in [0, 27814431486576L).
1623
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001624- The socket module now supports raw packets on Linux. The socket
1625 family is AF_PACKET.
1626
Tim Peters9ea17ac2001-02-02 05:57:15 +00001627- test_capi.py is a start at running tests of the Python C API. The tests
1628 are implemented by the new Modules/_testmodule.c.
1629
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001630- A new extension module, _symtable, provides provisional access to the
1631 internal symbol table used by the Python compiler. A higher-level
1632 interface will be added on top of _symtable in a future release.
1633
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001634- Removed the obsolete soundex module.
1635
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001636- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1637 the isSameNode method; NamedNodeMap the get method.
1638
1639- xml.sax.expatreader supports the lexical handler property; it
1640 generates comment, startCDATA, and endCDATA events.
1641
Tim Petersee826f82001-01-31 19:39:44 +00001642Windows changes
1643
1644- Build procedure: the zlib project is built in a different way that
1645 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001646 the zlib binary used. See PCbuild\readme.txt for details. Your old
1647 zlib-related directories can be deleted; you'll need to download fresh
1648 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001649
Tim Peters9ea17ac2001-02-02 05:57:15 +00001650- Build: New subproject _test for the benefit of test_capi.py (see above).
1651
Tim Petersb16c56f2001-02-02 21:24:51 +00001652- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1653 interface to some Python compiler internals).
1654
1655- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001656 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001657
Tim Petersa3a3a032000-11-30 05:22:44 +00001658What's New in Python 2.1 alpha 1?
1659=================================
1660
1661Core language, builtins, and interpreter
1662
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001663- There is a new Unicode companion to the PyObject_Str() API
1664 called PyObject_Unicode(). It behaves in the same way as the
1665 former, but assures that the returned value is an Unicode object
1666 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001667
Guido van Rossumf98eda02001-01-17 15:54:45 +00001668- The comparison operators support "rich comparison overloading" (PEP
1669 207). C extension types can provide a rich comparison function in
1670 the new tp_richcompare slot in the type object. The cmp() function
1671 and the C function PyObject_Compare() first try the new rich
1672 comparison operators before trying the old 3-way comparison. There
1673 is also a new C API PyObject_RichCompare() (which also falls back on
1674 the old 3-way comparison, but does not constrain the outcome of the
1675 rich comparison to a Boolean result).
1676
1677 The rich comparison function takes two objects (at least one of
1678 which is guaranteed to have the type that provided the function) and
1679 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1680 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1681 object, which may be NotImplemented (in which case the tp_compare
1682 slot function is used as a fallback, if defined).
1683
1684 Classes can overload individual comparison operators by defining one
1685 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001686 __ge__. There are no explicit "reflected argument" versions of
1687 these; instead, __lt__ and __gt__ are each other's reflection,
1688 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1689 reflection (similar at the C level). No other implications are
1690 made; in particular, Python does not assume that == is the Boolean
1691 inverse of !=, or that < is the Boolean inverse of >=. This makes
1692 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001693
1694 Classes or types that want to implement (in)equality tests but not
1695 the ordering operators (i.e. unordered types) should implement ==
1696 and !=, and raise an error for the ordering operators.
1697
Guido van Rossuma88479f2001-01-18 14:28:08 +00001698 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001699 Boolean; e.g. a matrix type might want to return a matrix of bits
1700 for A < B, giving elementwise comparisons. Such types should ensure
1701 that any interpretation of their value in a Boolean context raises
1702 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1703 at the C level) to always raise an exception.
1704
Guido van Rossuma88479f2001-01-18 14:28:08 +00001705- Complex numbers use rich comparisons to define == and != but raise
1706 an exception for <, <=, > and >=. Unfortunately, this also means
1707 that cmp() of two complex numbers raises an exception when the two
1708 numbers differ. Since it is not mathematically meaningful to compare
1709 complex numbers except for equality, I hope that this doesn't break
1710 too much code.
1711
Tim Peters3389f192001-02-18 08:48:49 +00001712- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001713 not defined by the language, other than that it's arbitrary but
1714 consistent (see the Reference Manual). An implementation detail changed
1715 in 2.1a1 such that None now compares less than any other object. Code
1716 relying on this new behavior (like code that relied on the previous
1717 behavior) does so at its own risk.
1718
Barry Warsaw573b5412001-01-15 20:43:18 +00001719- Functions and methods now support getting and setting arbitrarily
1720 named attributes (PEP 232). Functions have a new __dict__
1721 (a.k.a. func_dict) which hold the function attributes. Methods get
1722 and set attributes on their underlying im_func. It is a TypeError
1723 to set an attribute on a bound method.
1724
Guido van Rossum051e3352001-01-15 19:11:10 +00001725- The xrange() object implementation has been improved so that
1726 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1727 limitation that in this case len(xrange(sys.maxint)) can't be
1728 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1729 work fine as long as the index i doesn't actually reach 2**31.
1730 (Python uses regular ints for sequence and string indices; fixing
1731 that is much more work.)
1732
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001733- Two changes to from...import:
1734
Guido van Rossumba381232001-02-03 15:06:40 +00001735 1) "from M import X" now works even if (after loading module M)
1736 sys.modules['M'] is not a real module; it's basically a getattr()
1737 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001738
1739 2) "from M import *" now looks for M.__all__ to decide which names to
1740 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1741 filters out names starting with '_' as before. Whether or not
1742 __all__ exists, there's no restriction on the type of M.
1743
Guido van Rossumf61f1662001-01-10 20:13:55 +00001744- File objects have a new method, xreadlines(). This is the fastest
1745 way to iterate over all lines in a file:
1746
1747 for line in file.xreadlines():
1748 ...do something to line...
1749
1750 See the xreadlines module (mentioned below) for how to do this for
1751 other file-like objects.
1752
1753- Even if you don't use file.xreadlines(), you may expect a speedup on
1754 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001755 quite a bit in platform-specific ways: on systems (like Linux) that
1756 support flockfile(), getc_unlocked(), and funlockfile(), those are
1757 used by default. On systems (like Windows) without getc_unlocked(),
1758 a complicated (but still thread-safe) method using fgets() is used by
1759 default.
1760
Tim Petersd52269b2001-01-25 06:23:18 +00001761 You can force use of the fgets() method by #define'ing
1762 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001763 getc_unlocked()).
1764
Tim Petersd52269b2001-01-25 06:23:18 +00001765 You can force fgets() not to be used by #define'ing
1766 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001767 test_bufio.py fails -- and let us know if it does!).
1768
1769- In addition, the fileinput module, while still slower than the other
1770 methods on most platforms, has been sped up too, by using
1771 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001772
1773- Support for run-time warnings has been added, including a new
1774 command line option (-W) to specify the disposition of warnings.
1775 See the description of the warnings module below.
1776
1777- Extensive changes have been made to the coercion code. This mostly
1778 affects extension modules (which can now implement mixed-type
1779 numerical operators without having to use coercion), but
1780 occasionally, in boundary cases the coercion semantics have changed
1781 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001782 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001783 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001784 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001785
Guido van Rossumf98eda02001-01-17 15:54:45 +00001786- In connection with the coercion changes, a new built-in singleton
1787 object, NotImplemented is defined. This can be returned for
1788 operations that wish to indicate they are not implemented for a
1789 particular combination of arguments. From C, this is
1790 Py_NotImplemented.
1791
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001792- The interpreter accepts now bytecode files on the command line even
1793 if they do not have a .pyc or .pyo extension. On Linux, after executing
1794
Martin v. Löwise214baa2001-02-04 22:37:56 +00001795import imp,sys,string
1796magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1797reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1798open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001799
1800 any byte code file can be used as an executable (i.e. as an argument
1801 to execve(2)).
1802
Tim Peters9940b802000-12-01 07:59:35 +00001803- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001804 character. In 1.6 and earlier, they never produced a sign,
1805 and raised an error if the value of the long was too large
1806 to fit in a Python int. In 2.0, they produced a sign if and
1807 only if too large to fit in an int. This was inconsistent
1808 across platforms (because the size of an int varies across
1809 platforms), and inconsistent with hex() and oct(). Example:
1810
1811 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001812 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001813 'ffffffbe' # in 2.0 and before, on 32-bit machines
1814 >>> hex(-0x42L)
1815 '-0x42L' # in all versions of Python
1816
Tim Peters9940b802000-12-01 07:59:35 +00001817 The behavior of %d formats for negative Python longs remains
1818 the same as in 2.0 (although in 1.6 and before, they raised
1819 an error if the long didn't fit in a Python int).
1820
1821 %u formats don't make sense for Python longs, but are allowed
1822 and treated the same as %d in 2.1. In 2.0, a negative long
1823 formatted via %u produced a sign if and only if too large to
1824 fit in an int. In 1.6 and earlier, a negative long formatted
1825 via %u raised an error if it was too big to fit in an int.
1826
Guido van Rossum3661d392000-12-12 22:10:31 +00001827- Dictionary objects have an odd new method, popitem(). This removes
1828 an arbitrary item from the dictionary and returns it (in the form of
1829 a (key, value) pair). This can be useful for algorithms that use a
1830 dictionary as a bag of "to do" items and repeatedly need to pick one
1831 item. Such algorithms normally end up running in quadratic time;
1832 using popitem() they can usually be made to run in linear time.
1833
Tim Peters36cdad12000-12-29 02:06:45 +00001834Standard library
1835
Thomas Woutersfe385252001-01-19 23:16:56 +00001836- In the time module, the time argument to the functions strftime,
1837 localtime, gmtime, asctime and ctime is now optional, defaulting to
1838 the current time (in the local timezone).
1839
Guido van Rossumda91f222001-01-15 16:36:08 +00001840- The ftplib module now defaults to passive mode, which is deemed a
1841 more useful default given that clients are often inside firewalls
1842 these days. Note that this could break if ftplib is used to connect
1843 to a *server* that is inside a firewall, from outside; this is
1844 expected to be a very rare situation. To fix that, you can call
1845 ftp.set_pasv(0).
1846
Martin v. Löwis10a27872001-01-13 09:54:41 +00001847- The module site now treats .pth files not only for path configuration,
1848 but also supports extensions to the initialization code: Lines starting
1849 with import are executed.
1850
Guido van Rossumf61f1662001-01-10 20:13:55 +00001851- There's a new module, warnings, which implements a mechanism for
1852 issuing and filtering warnings. There are some new built-in
1853 exceptions that serve as warning categories, and a new command line
1854 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1855 turns warnings into errors). warnings.warn(message[, category])
1856 issues a warning message; this can also be called from C as
1857 PyErr_Warn(category, message).
1858
1859- A new module xreadlines was added. This exports a single factory
1860 function, xreadlines(). The intention is that this code is the
1861 absolutely fastest way to iterate over all lines in an open
1862 file(-like) object:
1863
1864 import xreadlines
1865 for line in xreadlines.xreadlines(file):
1866 ...do something to line...
1867
1868 This is equivalent to the previous the speed record holder using
1869 file.readlines(sizehint). Note that if file is a real file object
1870 (as opposed to a file-like object), this is equivalent:
1871
1872 for line in file.xreadlines():
1873 ...do something to line...
1874
Tim Peters36cdad12000-12-29 02:06:45 +00001875- The bisect module has new functions bisect_left, insort_left,
1876 bisect_right and insort_right. The old names bisect and insort
1877 are now aliases for bisect_right and insort_right. XXX_right
1878 and XXX_left methods differ in what happens when the new element
1879 compares equal to one or more elements already in the list: the
1880 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001881 right. Code that doesn't care where equal elements end up should
1882 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001883
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001884- The new curses.panel module wraps the panel library that forms part
1885 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1886
Guido van Rossumf61f1662001-01-10 20:13:55 +00001887- The SocketServer module now sets the allow_reuse_address flag by
1888 default in the TCPServer class.
1889
1890- A new function, sys._getframe(), returns the stack frame pointer of
1891 the caller. This is intended only as a building block for
1892 higher-level mechanisms such as string interpolation.
1893
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001894- The pyexpat module supports a number of new handlers, which are
1895 available only in expat 1.2. If invocation of a callback fails, it
1896 will report an additional frame in the traceback. Parser objects
1897 participate now in garbage collection. If expat reports an unknown
1898 encoding, pyexpat will try to use a Python codec; that works only
1899 for single-byte charsets. The parser type objects is exposed as
1900 XMLParserObject.
1901
1902- xml.dom now offers standard definitions for symbolic node type and
1903 exception code constants, and a hierarchy of DOM exceptions. minidom
1904 was adjusted to use them.
1905
1906- The conformance of xml.dom.minidom to the DOM specification was
1907 improved. It detects a number of additional error cases; the
1908 previous/next relationship works even when the tree is modified;
1909 Node supports the normalize() method; NamedNodeMap, DocumentType and
1910 DOMImplementation classes were added; Element supports the
1911 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1912 method.
1913
Guido van Rossumf61f1662001-01-10 20:13:55 +00001914Build issues
1915
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001916- For Unix (and Unix-compatible) builds, configuration and building of
1917 extension modules is now greatly automated. Rather than having to
1918 edit the Modules/Setup file to indicate which modules should be
1919 built and where their include files and libraries are, a
1920 distutils-based setup.py script now takes care of building most
1921 extension modules. All extension modules built this way are built
1922 as shared libraries. Only a few modules that must be linked
1923 statically are still listed in the Setup file; you won't need to
1924 edit their configuration.
1925
1926- Python should now build out of the box on Cygwin. If it doesn't,
1927 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001928
1929- Python now always uses its own (renamed) implementation of getopt()
1930 -- there's too much variation among C library getopt()
1931 implementations.
1932
1933- C++ compilers are better supported; the CXX macro is always set to a
1934 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001935
Tim Petersd92dfe02000-12-12 01:18:41 +00001936Windows changes
1937
1938- select module: By default under Windows, a select() call
1939 can specify no more than 64 sockets. Python now boosts
1940 this Microsoft default to 512. If you need even more than
1941 that, see the MS docs (you'll need to #define FD_SETSIZE
1942 and recompile Python from source).
1943
Guido van Rossumf61f1662001-01-10 20:13:55 +00001944- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1945 subdirectory is no more!
1946
Tim Petersa3a3a032000-11-30 05:22:44 +00001947
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001948What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001949=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001950
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001951Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001952changes are in the file HISTORY. If you are making the jump directly
1953from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1954HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001955
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001956Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1957the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1958http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001959
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001960--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001961
1962======================================================================
1963
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001964What's new in 2.0 (since release candidate 1)?
1965==============================================
1966
1967Standard library
1968
1969- The copy_reg module was modified to clarify its intended use: to
1970 register pickle support for extension types, not for classes.
1971 pickle() will raise a TypeError if it is passed a class.
1972
1973- Fixed a bug in gettext's "normalize and expand" code that prevented
1974 it from finding an existing .mo file.
1975
1976- Restored support for HTTP/0.9 servers in httplib.
1977
Tim Peters989b7b92000-10-16 20:24:53 +00001978- The math module was changed to stop raising OverflowError in case of
1979 underflow, and return 0 instead in underflow cases. Whether Python
1980 used to raise OverflowError in case of underflow was platform-
1981 dependent (it did when the platform math library set errno to ERANGE
1982 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001983
1984- Fixed a bug in StringIO that occurred when the file position was not
1985 at the end of the file and write() was called with enough data to
1986 extend past the end of the file.
1987
1988- Fixed a bug that caused Tkinter error messages to get lost on
1989 Windows. The bug was fixed by replacing direct use of
1990 interp->result with Tcl_GetStringResult(interp).
1991
1992- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1993 redirect response.
1994
1995- Several changes were made to distutils: Some debugging code was
1996 removed from util. Fixed the installer used when an external zip
1997 program (like WinZip) is not found; the source code for this
1998 installer is in Misc/distutils. check_lib() was modified to behave
1999 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
2000 test for whether installed modules are on sys.path was changed to
2001 use both normcase() and normpath().
2002
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00002003- Several minor bugs were fixed in the xml package (the minidom,
2004 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002005
2006- The regression test driver (regrtest.py) behavior when invoked with
2007 -l changed: It now reports a count of objects that are recognized as
2008 garbage but not freed by the garbage collector.
2009
Tim Peters989b7b92000-10-16 20:24:53 +00002010- The regression test for the math module was changed to test
2011 exceptional behavior when the test is run in verbose mode. Python
2012 cannot yet guarantee consistent exception behavior across platforms,
2013 so the exception part of test_math is run only in verbose mode, and
2014 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002015
2016Internals
2017
2018- PyOS_CheckStack() has been disabled on Win64, where it caused
2019 test_sre to fail.
2020
2021Build issues
2022
2023- Changed compiler flags, so that gcc is always invoked with -Wall and
2024 -Wstrict-prototypes. Users compiling Python with GCC should see
2025 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00002026 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00002027 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002028
Tim Petersa3a3a032000-11-30 05:22:44 +00002029- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002030
2031Tools and other miscellany
2032
2033- The compiler in Tools/compiler was updated to support the new
2034 language features introduced in 2.0: extended print statement, list
2035 comprehensions, and augmented assignments. The new compiler should
2036 also be backwards compatible with Python 1.5.2; the compiler will
2037 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00002038 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002039
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002040What's new in 2.0 release candidate 1 (since beta 2)?
2041=====================================================
2042
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00002043What is release candidate 1?
2044
2045We believe that release candidate 1 will fix all known bugs that we
2046intend to fix for the 2.0 final release. This release should be a bit
2047more stable than the previous betas. We would like to see even more
2048widespread testing before the final release, so we are producing this
2049release candidate. The final release will be exactly the same unless
2050any show-stopping (or brown bag) bugs are found by testers of the
2051release candidate.
2052
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002053All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002054to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002055
2056Core language, builtins, and interpreter
2057
2058- A bug that caused crashes when __coerce__ was used with augmented
2059 assignment, e.g. +=, was fixed.
2060
2061- Raise ZeroDivisionError when raising zero to a negative number,
2062 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
2063 power operator and the result of math.pow(0.0, -2.0) will vary by
2064 platform. On Linux, it raises a ValueError.
2065
2066- A bug in Unicode string interpolation was fixed that occasionally
2067 caused errors with formats including "%%". For example, the
2068 following expression "%% %s" % u"abc" no longer raises a TypeError.
2069
2070- Compilation of deeply nested expressions raises MemoryError instead
2071 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
2072
2073- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
2074 rendering them useless. They are now written in binary mode again.
2075
2076Standard library
2077
2078- Keyword arguments are now accepted for most pattern and match object
2079 methods in SRE, the standard regular expression engine.
2080
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002081- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00002082 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002083
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002084- Several bugs in the Unicode handling and error handling in _tkinter
2085 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002086
2087- Fix memory management errors in Merge() and Tkapp_Call() routines.
2088
2089- Several changes were made to cStringIO to make it compatible with
2090 the file-like object interface and with StringIO. If operations are
2091 performed on a closed object, an exception is raised. The truncate
2092 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00002093 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002094
2095- There were many changes made to the linuxaudiodev module and its
2096 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00002097 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002098
2099 Note that this module is named poorly, because it should work
2100 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00002101 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002102
2103 The module now raises exceptions when errors occur instead of
2104 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
2105 audio) and defines a getptr() method that calls the
2106 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
2107
2108- The library_version attribute, introduced in an earlier beta, was
2109 removed because it can not be supported with early versions of the C
2110 readline library, which provides no way to determine the version at
2111 compile-time.
2112
2113- The binascii module is now enabled on Win64.
2114
Tim Peters46446d62000-10-09 21:19:31 +00002115- tokenize.py no longer suffers "recursion depth" errors when parsing
2116 programs with very long string literals.
2117
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002118Internals
2119
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002120- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002121 which is called when the interpreter starts up to determine where
2122 the standard library is installed. These vulnerabilities affect all
2123 previous versions of Python and can be exploited by setting very
2124 long values for PYTHONHOME or argv[0]. The risk is greatest for a
2125 setuid Python script, although use of the wrapper in
2126 Misc/setuid-prog.c will eliminate the vulnerability.
2127
2128- Fixed garbage collection bugs in instance creation that were
2129 triggered when errors occurred during initialization. The solution,
2130 applied in cPickle and in PyInstance_New(), is to call
2131 PyObject_GC_Init() after the initialization of the object's
2132 container attributes is complete.
2133
2134- pyexpat adds definitions of PyModule_AddStringConstant and
2135 PyModule_AddObject if the Python version is less than 2.0, which
2136 provides compatibility with PyXML on Python 1.5.2.
2137
2138- If the platform has a bogus definition for LONG_BIT (the number of
2139 bits in a long), an error will be reported at compile time.
2140
2141- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
2142 collection crashes and possibly other, unreported crashes.
2143
2144- Fixed a memory leak in _PyUnicode_Fini().
2145
2146Build issues
2147
2148- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002149 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00002150 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002151
2152- The mmap.PAGESIZE constant is now initialized using sysconf when
2153 possible, which eliminates a dependency on -lucb for Reliant UNIX.
2154
2155- The md5 file should now compile on all platforms.
2156
2157- The select module now compiles on platforms that do not define
2158 POLLRDNORM and related constants.
2159
2160- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00002161 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002162
Jeremy Hylton10921202000-10-09 18:34:12 +00002163- BeOS: A number of changes were made to the build and installation
2164 process. ar-fake now operates on a directory of object files.
2165 dl_export.h is gone, and its macros now appear on the mwcc command
2166 line during build on PPC BeOS.
2167
Jeremy Hyltond6e20232000-10-16 20:08:38 +00002168- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00002169 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00002170
2171- Cygwin: Support for shared libraries, Tkinter, and sockets.
2172
2173- SunOS 4.1.4_JL: Fix test for directory existence in configure.
2174
2175Tools and other miscellany
2176
2177- Removed debugging prints from main used with freeze.
2178
Tim Peters46446d62000-10-09 21:19:31 +00002179- IDLE auto-indent no longer crashes when it encounters Unicode
2180 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002181
2182What's new in 2.0 beta 2 (since beta 1)?
2183========================================
2184
2185Core language, builtins, and interpreter
2186
Tim Peters482c0212000-09-26 06:33:09 +00002187- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002188 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002189
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002190- Add -h and -V command line options to print the usage message and
2191 Python version number and exit immediately.
2192
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002193- eval() and exec accept Unicode objects as code parameters.
2194
2195- getattr() and setattr() now also accept Unicode objects for the
2196 attribute name, which are converted to strings using the default
2197 encoding before lookup.
2198
2199- Multiplication on string and Unicode now does proper bounds
2200 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2201 string is too long."
2202
2203- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002204 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002205
Jeremy Hylton1b618592000-09-26 05:32:36 +00002206
2207Standard library and extensions
2208
Guido van Rossum5b08f132001-04-16 02:05:23 +00002209- socket module: the OpenSSL code now adds support for RAND_status()
2210 and EGD (Entropy Gathering Device).
2211
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002212- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002213 argument checking; it still takes no arguments.
2214
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002215- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002216
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002217- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002218
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002219- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002220
2221- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002222 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002223
2224- copy: Copy Unicode objects atomically.
2225
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002226- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002227
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002228- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002229
Fred Drake67233bc2000-09-26 16:40:27 +00002230- dbm: Add get() and setdefault() methods to dbm object. Add constant
2231 `library' to module that names the library used. Added doc strings
2232 and method names to error messages. Uses configure to determine
2233 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2234 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002235
2236- distutils: Update to version 0.9.3.
2237
2238- dl: Add several dl.RTLD_ constants.
2239
2240- fpectl: Now supported on FreeBSD.
2241
2242- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2243 found by the collector will be saved in gc.garbage. This is useful
2244 for debugging a program that creates reference cycles.
2245
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002246- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002247 of HTTP class. Do not close socket on zero-length response. Do not
2248 crash when server sends invalid content-length header.
2249
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002250- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002251
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002252- marshal: When reading a short, sign-extend on platforms where shorts
2253 are bigger than 16 bits. When reading a long, repair the unportable
2254 sign extension that was being done for 64-bit machines. (It assumed
2255 that signed right shift sign-extends.)
2256
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002257- operator: Add contains(), invert(), __invert__() as aliases for
2258 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002259
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002260- os: Add support for popen2() and popen3() on all platforms where
2261 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002262
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002263- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002264 clicking on a file in Explorer (or passing the file name to the
2265 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002266
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002267- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002268 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002269
2270- pickle: Now raises ValueError when an invalid pickle that contains
2271 a non-string repr where a string repr was expected. This behavior
2272 matches cPickle.
2273
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002274- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002275
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002276- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002277
2278- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002279 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002280 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002281
2282- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002283 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002284
2285- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002286 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002287 few cycles during startup since the first call to
2288 setdefaultencoding() will initialize the codec registry and the
2289 encodings package.
2290
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002291- socket: Support for size hint in readlines() method of object returned
2292 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002293
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002294- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002295 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002296 is followed by whitespace.
2297
Tim Petersa3a3a032000-11-30 05:22:44 +00002298- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002299
2300- struct: Check ranges for bytes and shorts.
2301
2302- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002303 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002304
2305- Tkinter: Image objects are now guaranteed to have unique ids. Set
2306 event.delta to zero if Tk version doesn't support mousewheel.
2307 Removed some debugging prints.
2308
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002309- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002310
Fred Drake67233bc2000-09-26 16:40:27 +00002311- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002312 which works around a bug in Norton AntiVirus 2000 that leads directly
2313 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002314
2315- xml: New version detection code allows PyXML to override standard
2316 XML package if PyXML version is greater than 0.6.1.
2317
Fred Drake64bb3802000-09-26 16:21:35 +00002318- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2319 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2320 tree only for nodes which are sufficiently interesting to a specific
2321 application. Does not provide the HTML-specific extensions. Still
2322 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002323
Fred Drake64bb3802000-09-26 16:21:35 +00002324- xml.sax: SAX 2 support for Python, including all the handler
2325 interfaces needed to process XML 1.0 compliant XML. Some
2326 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002327
Fred Drake64bb3802000-09-26 16:21:35 +00002328- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2329 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002330
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002331
Jeremy Hylton1b618592000-09-26 05:32:36 +00002332C API
2333
2334- Add three new convenience functions for module initialization --
2335 PyModule_AddObject(), PyModule_AddIntConstant(), and
2336 PyModule_AddStringConstant().
2337
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002338- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002339 removed and add #error to Python.h if NULL isn't defined after
2340 #include of stdio.h.
2341
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002342- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002343 backwards compatibility (at the source level) with old extensions.
2344
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002345- A wrapper API was added for signal() and sigaction(). Instead of
2346 either function, always use PyOS_getsig() to get a signal handler
2347 and PyOS_setsig() to set one. A new convenience typedef
2348 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002349
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002350- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002351 internal data buffer and size of a string object -- or the default
2352 encoded version of a Unicode object.
2353
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002354- PyString_Size() and PyString_AsString() accept Unicode objects.
2355
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002356- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002357 exists). INT_MAX and LONG_MAX will always be defined, even if
2358 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002359
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002360- PyFloat_FromString takes a second argument, pend, that was
2361 effectively useless. It is now officially useless but preserved for
2362 backwards compatibility. If the pend argument is not NULL, *pend is
2363 set to NULL.
2364
2365- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2366 for the attribute name. See note on getattr() above.
2367
2368- A few bug fixes to argument processing for Unicode.
2369 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2370 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2371 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002372 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002373
2374- Py_BuildValue accepts B format (for bgen-generated code).
2375
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002376
Jeremy Hylton1b618592000-09-26 05:32:36 +00002377Internals
2378
2379- On Unix, fix code for finding Python installation directory so that
2380 it works when argv[0] is a relative path.
2381
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002382- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002383 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002384 rather than by generating a copy of the object.
2385
Tim Peters482c0212000-09-26 06:33:09 +00002386- Several of the internal Unicode tables are much smaller now, and
2387 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002388
Jeremy Hylton97693b02000-09-26 17:42:51 +00002389- In the garbage collector: Fixed bug in collection of tuples. Fixed
2390 bug that caused some instances to be removed from the container set
2391 while they were still live. Fixed parsing in gc.set_debug() for
2392 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002393
2394- Fixed refcount problem in instance deallocation that only occurred
2395 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2396
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002397- On Windows, getpythonregpath is now protected against null data in
2398 registry key.
2399
2400- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002401 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002402
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002403
Jeremy Hylton1b618592000-09-26 05:32:36 +00002404Build and platform-specific issues
2405
2406- Better support of GNU Pth via --with-pth configure option.
2407
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002408- Python/C API now properly exposed to dynamically-loaded extension
2409 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002410
2411- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2412 Don't define MS_SYNC to be zero when it is undefined. Added missing
2413 prototypes in posixmodule.c.
2414
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002415- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002416 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002417
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002418- Fix largefile support on older NetBSD systems and OpenBSD by adding
2419 define for TELL64.
2420
2421
2422Tools and other miscellany
2423
2424- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2425
2426- freeze: The modulefinder now works with 2.0 opcodes.
2427
Tim Petersa3a3a032000-11-30 05:22:44 +00002428- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002429 Move hackery of sys.argv until after the Tk instance has been
2430 created, which allows the application-specific Tkinter
2431 initialization to be executed if present; also pass an explicit
2432 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002433
Jeremy Hylton1b618592000-09-26 05:32:36 +00002434
2435What's new in 2.0 beta 1?
2436=========================
2437
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002438Source Incompatibilities
2439------------------------
2440
2441None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2442such as single-argument append(), connect() and bind(), and changes to
2443str(long) and repr(float).
2444
2445
2446Binary Incompatibilities
2447------------------------
2448
2449- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2450with Python 2.0; these extensions will have to be rebuilt for Python
24512.0.
2452
2453- On Windows, attempting to import a third party extension built for
2454Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2455can do about this. Check your PYTHONPATH environment variable!
2456
2457- Python bytecode files (*.pyc and *.pyo) are not compatible between
2458releases.
2459
2460
2461Overview of Changes Since 1.6
2462-----------------------------
2463
2464There are many new modules (including brand new XML support through
2465the xml package, and i18n support through the gettext module); a list
2466of all new modules is included below. Lots of bugs have been fixed.
2467
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002468The process for making major new changes to the language has changed
2469since Python 1.6. Enhancements must now be documented by a Python
2470Enhancement Proposal (PEP) before they can be accepted.
2471
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002472There are several important syntax enhancements, described in more
2473detail below:
2474
2475 - Augmented assignment, e.g. x += 1
2476
2477 - List comprehensions, e.g. [x**2 for x in range(10)]
2478
2479 - Extended import statement, e.g. import Module as Name
2480
2481 - Extended print statement, e.g. print >> file, "Hello"
2482
2483Other important changes:
2484
2485 - Optional collection of cyclical garbage
2486
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002487Python Enhancement Proposal (PEP)
2488---------------------------------
2489
2490PEP stands for Python Enhancement Proposal. A PEP is a design
2491document providing information to the Python community, or describing
2492a new feature for Python. The PEP should provide a concise technical
2493specification of the feature and a rationale for the feature.
2494
2495We intend PEPs to be the primary mechanisms for proposing new
2496features, for collecting community input on an issue, and for
2497documenting the design decisions that have gone into Python. The PEP
2498author is responsible for building consensus within the community and
2499documenting dissenting opinions.
2500
2501The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002502
2503Augmented Assignment
2504--------------------
2505
2506This must have been the most-requested feature of the past years!
2507Eleven new assignment operators were added:
2508
Guido van Rossume905e952000-09-05 12:42:46 +00002509 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002510
2511For example,
2512
2513 A += B
2514
2515is similar to
2516
2517 A = A + B
2518
2519except that A is evaluated only once (relevant when A is something
2520like dict[index].attr).
2521
2522However, if A is a mutable object, A may be modified in place. Thus,
2523if A is a number or a string, A += B has the same effect as A = A+B
2524(except A is only evaluated once); but if a is a list, A += B has the
2525same effect as A.extend(B)!
2526
2527Classes and built-in object types can override the new operators in
2528order to implement the in-place behavior; the not-in-place behavior is
2529used automatically as a fallback when an object doesn't implement the
2530in-place behavior. For classes, the method name is derived from the
2531method name for the corresponding not-in-place operator by inserting
2532an 'i' in front of the name, e.g. __iadd__ implements in-place
2533__add__.
2534
2535Augmented assignment was implemented by Thomas Wouters.
2536
2537
2538List Comprehensions
2539-------------------
2540
2541This is a flexible new notation for lists whose elements are computed
2542from another list (or lists). The simplest form is:
2543
2544 [<expression> for <variable> in <sequence>]
2545
Guido van Rossum56db0952000-09-06 23:34:25 +00002546For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002547This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002548
2549You can also add a condition:
2550
2551 [<expression> for <variable> in <sequence> if <condition>]
2552
2553For example, [w for w in words if w == w.lower()] would yield the list
2554of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002555than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002556
2557You can also have nested for loops and more than one 'if' clause. For
2558example, here's a function that flattens a sequence of sequences::
2559
2560 def flatten(seq):
2561 return [x for subseq in seq for x in subseq]
2562
2563 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2564
2565This prints
2566
2567 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2568
2569List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002570Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002571
2572
2573Extended Import Statement
2574-------------------------
2575
2576Many people have asked for a way to import a module under a different
2577name. This can be accomplished like this:
2578
2579 import foo
2580 bar = foo
2581 del foo
2582
2583but this common idiom gets old quickly. A simple extension of the
2584import statement now allows this to be written as follows:
2585
2586 import foo as bar
2587
2588There's also a variant for 'from ... import':
2589
2590 from foo import bar as spam
2591
2592This also works with packages; e.g. you can write this:
2593
2594 import test.regrtest as regrtest
2595
2596Note that 'as' is not a new keyword -- it is recognized only in this
2597context (this is only possible because the syntax for the import
2598statement doesn't involve expressions).
2599
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002600Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002601
2602
2603Extended Print Statement
2604------------------------
2605
2606Easily the most controversial new feature, this extension to the print
2607statement adds an option to make the output go to a different file
2608than the default sys.stdout.
2609
2610For example, to write an error message to sys.stderr, you can now
2611write:
2612
2613 print >> sys.stderr, "Error: bad dog!"
2614
2615As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002616evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002617
2618 print >> None, "Hello world"
2619
2620is equivalent to
2621
2622 print "Hello world"
2623
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002624Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002625
2626
2627Optional Collection of Cyclical Garbage
2628---------------------------------------
2629
2630Python is now equipped with a garbage collector that can hunt down
2631cyclical references between Python objects. It's no replacement for
2632reference counting; in fact, it depends on the reference counts being
2633correct, and decides that a set of objects belong to a cycle if all
2634their reference counts can be accounted for from their references to
2635each other. This devious scheme was first proposed by Eric Tiedemann,
2636and brought to implementation by Neil Schemenauer.
2637
2638There's a module "gc" that lets you control some parameters of the
2639garbage collection. There's also an option to the configure script
2640that lets you enable or disable the garbage collection. In 2.0b1,
2641it's on by default, so that we (hopefully) can collect decent user
2642experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002643performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002644off by default in the final 2.0 release.
2645
2646
2647Smaller Changes
2648---------------
2649
2650A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2651map(None, seq1, seq2, ...) when the sequences have the same length;
2652i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2653the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002654zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002655
2656sys.version_info is a tuple (major, minor, micro, level, serial).
2657
2658Dictionaries have an odd new method, setdefault(key, default).
2659dict.setdefault(key, default) returns dict[key] if it exists; if not,
2660it sets dict[key] to default and returns that value. Thus:
2661
2662 dict.setdefault(key, []).append(item)
2663
2664does the same work as this common idiom:
2665
2666 if not dict.has_key(key):
2667 dict[key] = []
2668 dict[key].append(item)
2669
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002670There are two new variants of SyntaxError that are raised for
2671indentation-related errors: IndentationError and TabError.
2672
2673Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2674escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002675
2676The limits on the size of expressions and file in Python source code
2677have been raised from 2**16 to 2**32. Previous versions of Python
2678were limited because the maximum argument size the Python VM accepted
2679was 2**16. This limited the size of object constructor expressions,
2680e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2681limit was raised thanks to a patch by Charles Waldman that effectively
2682fixes the problem. It is now much more likely that you will be
2683limited by available memory than by an arbitrary limit in Python.
2684
2685The interpreter's maximum recursion depth can be modified by Python
2686programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2687limit is the maximum number of recursive calls that can be made by
2688Python code. The limit exists to prevent infinite recursion from
2689overflowing the C stack and causing a core dump. The default value is
26901000. The maximum safe value for a particular platform can be found
2691by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002692
2693New Modules and Packages
2694------------------------
2695
2696atexit - for registering functions to be called when Python exits.
2697
2698imputil - Greg Stein's alternative API for writing custom import
2699hooks.
2700
2701pyexpat - an interface to the Expat XML parser, contributed by Paul
2702Prescod.
2703
2704xml - a new package with XML support code organized (so far) in three
2705subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2706would fill a volume. There's a special feature whereby a
2707user-installed package named _xmlplus overrides the standard
2708xmlpackage; this is intended to give the XML SIG a hook to distribute
2709backwards-compatible updates to the standard xml package.
2710
2711webbrowser - a platform-independent API to launch a web browser.
2712
2713
Guido van Rossume905e952000-09-05 12:42:46 +00002714Changed Modules
2715---------------
2716
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002717array -- new methods for array objects: count, extend, index, pop, and
2718remove
2719
2720binascii -- new functions b2a_hex and a2b_hex that convert between
2721binary data and its hex representation
2722
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002723calendar -- Many new functions that support features including control
2724over which day of the week is the first day, returning strings instead
2725of printing them. Also new symbolic constants for days of week,
2726e.g. MONDAY, ..., SUNDAY.
2727
2728cgi -- FieldStorage objects have a getvalue method that works like a
2729dictionary's get method and returns the value attribute of the object.
2730
2731ConfigParser -- The parser object has new methods has_option,
2732remove_section, remove_option, set, and write. They allow the module
2733to be used for writing config files as well as reading them.
2734
2735ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002736optionally support the RFC 959 REST command.
2737
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002738gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002739
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002740httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2741the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002742
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002743locale -- implement getdefaultlocale for Win32 and Macintosh
2744
2745marshal -- no longer dumps core when marshaling deeply nested or
2746recursive data structures
2747
2748os -- new functions isatty, seteuid, setegid, setreuid, setregid
2749
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002750os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2751support under Unix.
2752
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002753os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002754
2755os.path -- fix semantics of os.path.commonprefix
2756
2757smtplib -- support for sending very long messages
2758
2759socket -- new function getfqdn()
2760
2761readline -- new functions to read, write and truncate history files.
2762The readline section of the library reference manual contains an
2763example.
2764
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002765select -- add interface to poll system call
2766
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002767shutil -- new copyfileobj function
2768
2769SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2770HTTP server.
2771
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002772Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002773
2774urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002775e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002776
2777whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002778
2779
2780Obsolete Modules
2781----------------
2782
2783None. However note that 1.6 made a whole slew of modules obsolete:
2784stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2785poly, zmod, strop, util, whatsound.
2786
2787
2788Changed, New, Obsolete Tools
2789----------------------------
2790
Tim Peters8b092332000-09-05 20:15:25 +00002791None.
Guido van Rossume905e952000-09-05 12:42:46 +00002792
2793
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002794C-level Changes
2795---------------
2796
2797Several cleanup jobs were carried out throughout the source code.
2798
2799All C code was converted to ANSI C; we got rid of all uses of the
2800Py_PROTO() macro, which makes the header files a lot more readable.
2801
2802Most of the portability hacks were moved to a new header file,
2803pyport.h; several other new header files were added and some old
2804header files were removed, in an attempt to create a more rational set
2805of header files. (Few of these ever need to be included explicitly;
2806they are all included by Python.h.)
2807
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002808Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002809and Win64, especially for the new Intel Itanium processor. Mick also
2810added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002811
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002812The C APIs to return an object's size have been update to consistently
2813use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2814previous versions, the abstract interfaces used PyXXX_Length and the
2815concrete interfaces used PyXXX_Size. The old names,
2816e.g. PyObject_Length, are still available for backwards compatibility
2817at the API level, but are deprecated.
2818
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002819The PyOS_CheckStack function has been implemented on Windows by
2820Fredrik Lundh. It prevents Python from failing with a stack overflow
2821on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002822
2823The GC changes resulted in creation of two new slots on object,
2824tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002825the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002826
2827The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002828C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002829
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002830PyErr_Format has been updated to automatically calculate the size of
2831the buffer needed to hold the formatted result string. This change
2832prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002833
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002834New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002835
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002836PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2837that are the same as their non-Ex counterparts except they take an
2838extra flag argument that tells them to close the file when done.
2839
2840XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002841
Tim Peters8b092332000-09-05 20:15:25 +00002842
2843Windows Changes
2844---------------
2845
2846New popen2/popen3/peopen4 in os module (see Changed Modules above).
2847
2848os.popen is much more usable on Windows 95 and 98. See Microsoft
2849Knowledge Base article Q150956. The Win9x workaround described there
2850is implemented by the new w9xpopen.exe helper in the root of your
2851Python installation. Note that Python uses this internally; it is not
2852a standalone program.
2853
2854Administrator privileges are no longer required to install Python
2855on Windows NT or Windows 2000. If you have administrator privileges,
2856Python's registry info will be written under HKEY_LOCAL_MACHINE.
2857Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002858under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002859uses of Python, but will prevent some advanced uses from working
2860(for example, running a Python script as an NT service, or possibly
2861from CGI).
2862
2863[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2864installer; instead, it installs the needed Tcl/Tk files directly in the
2865Python directory. If you already have a Tcl/Tk installation, this
2866wastes some disk space (about 4 Megs) but avoids problems with
2867conflicting Tcl/Tk installations, and makes it much easier for Python
2868to ensure that Tcl/Tk can find all its files.
2869
2870[This was new in 1.6] The Windows installer now installs by default in
2871\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2872
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002873
2874Updates to the changes between 1.5.2 and 1.6
2875--------------------------------------------
2876
2877The 1.6 NEWS file can't be changed after the release is done, so here
2878is some late-breaking news:
2879
2880New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2881and changes to getlocale() and setlocale().
2882
2883The new module is now enabled per default.
2884
2885It is not true that the encodings codecs cannot be used for normal
2886strings: the string.encode() (which is also present on 8-bit strings
2887!) allows using them for 8-bit strings too, e.g. to convert files from
2888cp1252 (Windows) to latin-1 or vice-versa.
2889
2890Japanese codecs are available from Tamito KAJIYAMA:
2891http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2892
2893
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002894======================================================================