blob: e89b789ba13d23e24f5c89d08ef2d0363208f49d [file] [log] [blame]
Tim Petersabf925f2001-09-28 21:53:42 +00001What's New in Python 2.2b1?
2Release date: 28-Sep-2100
3===========================
4
5Type/class unification and new-style classes
6
Guido van Rossum687ae002001-10-15 22:03:32 +00007- New-style classes are now always dynamic (except for built-in and
Guido van Rossum3eea25c2001-10-16 00:46:57 +00008 extension types). There is no longer a performance penalty, and I
Guido van Rossum687ae002001-10-15 22:03:32 +00009 no longer see another reason to keep this baggage around. One relic
Guido van Rossum3eea25c2001-10-16 00:46:57 +000010 remains: the __dict__ of a new-style class is a read-only proxy; you
11 must set the class's attribute to modify it. As a consequence, the
Guido van Rossum687ae002001-10-15 22:03:32 +000012 __defined__ attribute of new-style types no longer exists, for lack
13 of need: there is once again only one __dict__ (although in the
Guido van Rossum3eea25c2001-10-16 00:46:57 +000014 future a __cache__ may be resurrected with a similar function, if I
15 can prove that it actually speeds things up).
Guido van Rossum50fda3b2001-10-04 19:46:06 +000016
Tim Peters1c9ca872001-10-04 06:43:12 +000017- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
18 always returned None, even when there was a class docstring).
19
20- doctest now finds and runs docstrings attached to new-style classes,
21 class methods, static methods, and properties.
22
Guido van Rossum9074ef62001-10-16 21:34:49 +000023Core and builtins
Tim Petersabf925f2001-09-28 21:53:42 +000024
Guido van Rossuma8bcf802001-10-15 15:53:58 +000025- A very subtle syntactical pitfall in list comprehensions was fixed.
26 For example: [a+b for a in 'abc', for b in 'def']. The comma in
27 this example is a mistake. Previously, this would silently let 'a'
28 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
29 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
30 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
31 Note that [a for a in <singleton>] is a convoluted way to say
32 [<singleton>] anyway, so it's not like any expressiveness is lost.
33
Guido van Rossum9074ef62001-10-16 21:34:49 +000034- getattr(obj, name, default) now only catches AttributeError, as
35 documented, rather than returning the default value for all
36 exceptions (which could mask bugs in a __getattr__ hook, for
37 example).
38
39Extension modules
40
41- thread.start_new_thread() now returns the thread ID (previously None).
42
Martin v. Löwis16dc7f42001-09-30 20:32:11 +000043- binascii has now two quopri support functions, a2b_qp and b2a_qp.
44
Martin v. Löwis0daad592001-09-30 21:09:59 +000045- readline now supports setting the startup_hook and the pre_event_hook.
46
Martin v. Löwis61c5edf2001-10-18 04:06:00 +000047- posix supports chroot and setgroups where available.
Martin v. Löwis16628c92001-10-04 22:46:41 +000048
Guido van Rossum9074ef62001-10-16 21:34:49 +000049- Decompression objects in the zlib module now accept an optional
50 second parameter to decompress() that specifies the maximum amount
51 of memory to use for the uncompressed data.
Tim Petersabf925f2001-09-28 21:53:42 +000052
Guido van Rossum9074ef62001-10-16 21:34:49 +000053Library
Guido van Rossum3c288632001-10-16 21:13:49 +000054
Tim Peters7402f792001-10-02 03:53:41 +000055- doctest now excludes functions and classes not defined by the module
56 being tested, thanks to Tim Hochberg.
57
Guido van Rossumc4b09b42001-10-04 10:19:00 +000058- profile now produces correct output in situations where an exception
59 raised in Python is cleared by C code (e.g. hasattr()). This used
60 to cause wrong output, including spurious claims of recursive
61 functions and attribution of time spent to the wrong function.
62
Tim Peters0a1fc4e2001-10-07 03:12:08 +000063 The code and documentation for the derived OldProfile and HotProfile
64 profiling classes was removed. The code hasn't worked for years (if
65 you tried to use them, they raised exceptions). OldProfile
66 intended to reproduce the behavior of the profiler Python used more
67 than 7 years ago, and isn't interesting anymore. HotProfile intended
68 to provide a faster profiler (but producing less information), and
69 that's a worthy goal we intend to meet via a different approach (but
70 without losing information).
71
Tim Peterscce092d2001-10-09 05:31:56 +000072- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +000073 a much better system-specific calibration constant. The constant can
74 now be specified in an instance constructor, or as a Profile class or
75 instance variable, instead of by editing profile.py's source code.
76 Calibration must still be done manually (see the docs for the profile
77 module).
78
79 Note that Profile.calibrate() must be overriden by subclasses.
80 Improving the accuracy required exploiting detailed knowledge of
81 profiler internals; the earlier method abstracted away the details
82 and measured a simplified model instead, but consequently computed
83 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +000084
Martin v. Löwis16dc7f42001-09-30 20:32:11 +000085- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +000086 which indicates whether output is intended for the header 'Q'
87 encoding.
88
Guido van Rossuma5343cc2001-10-18 18:02:07 +000089- The SocketServer.ThreadingMixIn class now closes the request after
90 finish_request() returns. (Not when it errors out though.)
91
Guido van Rossumed554f62001-10-02 23:15:37 +000092Tools/Demos
93
94- Demo/dns was removed. It no longer serves any purpose; a package
95 derived from it is now maintained by Anthony Baxter, see
96 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +000097
98Build
99
100C API
101
Tim Petersd38b1c72001-09-30 05:09:37 +0000102- PyLong_AsLongLong() now accepts int (as well as long) arguments.
103 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
104 as long) arguments.
105
Guido van Rossum3c288632001-10-16 21:13:49 +0000106- PyThread_start_new_thread() now returns a long int giving the thread
107 ID, if one can be calculated; it returns -1 for error, 0 if no
108 thread ID is calculated (this is an incompatible change, but only
109 the thread module used this API). This code has only really been
110 tested on Linux and Windows; other platforms please beware (and
111 report any bugs or strange behavior).
112
Tim Petersabf925f2001-09-28 21:53:42 +0000113New platforms
114
115Tests
116
117Windows
118
Tim Peters04cf1d32001-10-09 22:39:40 +0000119- Installer: If you install IDLE, and don't disable file-extension
120 registration, a new "Edit with IDLE" context (right-click) menu entry
121 is created for .py and .pyw files.
122
Tim Peters1ce3cf72001-10-01 17:58:40 +0000123- The signal module now supports SIGBREAK on Windows, thanks to Steven
124 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
125 action remains to call Win32 ExitProcess(). This can be changed via
126 signal.signal(). For example:
127
128 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
129 # (SIGINT) behavior.
130 import signal
131 signal.signal(signal.SIGBREAK,
132 signal.default_int_handler)
133
134 try:
135 while 1:
136 pass
137 except KeyboardInterrupt:
138 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
139 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
140 # program without the possibility for any Python-level cleanup).
141 print "Clean exit"
142
Tim Petersabf925f2001-09-28 21:53:42 +0000143
Tim Petersb07352e2001-09-08 01:25:47 +0000144What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000145Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000146===========================
147
Guido van Rossum808eea72001-09-25 04:15:41 +0000148Type/class unification and new-style classes
149
150- pydoc and inspect are now aware of new-style classes;
151 e.g. help(list) at the interactive prompt now shows proper
152 documentation for all operations on list objects.
153
154- Applications using Jim Fulton's ExtensionClass module can now safely
155 be used with Python 2.2. In particular, Zope 2.4.1 now works with
156 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
157 examples also work again. It is hoped that Gtk and Boost also work
158 with 2.2a4 and beyond. (If you can confirm this, please write
159 webmaster@python.org; if there are still problems, please open a bug
160 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000161
Tim Peters66c1a522001-09-24 21:17:50 +0000162- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
163 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
164 in the constructed property object. fget, fset and fdel weren't
165 discoverable from Python in 2.2a3. __doc__ is new, and allows to
166 associate a docstring with a property.
167
Guido van Rossum808eea72001-09-25 04:15:41 +0000168- Comparison overloading is now more completely implemented. For
169 example, a str subclass instance can properly be compared to a str
170 instance, and it can properly overload comparison. Ditto for most
171 other built-in object types.
172
173- The repr() of new-style classes has changed; instead of <type
174 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
175 *except* for built-in types, which are still rendered as <type
176 'Foo'> (to avoid upsetting existing code that might parse or
177 otherwise rely on repr() of certain type objects).
178
179- The repr() of new-style objects is now always <Foo object at XXX>;
180 previously, it was sometimes <Foo instance at XXX>.
181
182- For new-style classes, what was previously called __getattr__ is now
183 called __getattribute__. This method, if defined, is called for
184 *every* attribute access. A new __getattr__ hook mor similar to the
185 one in classic classes is defined which is called only if regular
186 attribute access raises AttributeError; to catch *all* attribute
187 access, you can use __getattribute__ (for new-style classes). If
188 both are defined, __getattribute__ is called first, and if it raises
189 AttributeError, __getattr__ is called.
190
191- The __class__ attribute of new-style objects can be assigned to.
192 The new class must have the same C-level object layout as the old
193 class.
194
195- The builtin file type can be subclassed now. In the usual pattern,
196 "file" is the name of the builtin type, and file() is a new builtin
197 constructor, with the same signature as the builtin open() function.
198 file() is now the preferred way to open a file.
199
200- Previously, __new__ would only see sequential arguments passed to
201 the type in a constructor call; __init__ would see both sequential
202 and keyword arguments. This made no sense whatsoever any more, so
203 now both __new__ and __init__ see all arguments.
204
205- Previously, hash() applied to an instance of a subclass of str or
206 unicode always returned 0. This has been repaired.
207
208- Previously, an operation on an instance of a subclass of an
209 immutable type (int, long, float, complex, tuple, str, unicode),
210 where the subtype didn't override the operation (and so the
211 operation was handled by the builtin type), could return that
212 instance instead a value of the base type. For example, if s was of
213 a str sublass type, s[:] returned s as-is. Now it returns a str
214 with the same value as s.
215
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000216- Provisional support for pickling new-style objects has been added.
217
Guido van Rossum808eea72001-09-25 04:15:41 +0000218Core
219
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000220- file.writelines() now accepts any iterable object producing strings.
221
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000222- PyUnicode_FromEncodedObject() now works very much like
223 PyObject_Str(obj) in that it tries to use __str__/tp_str
224 on the object if the object is not a string or buffer. This
225 makes unicode() behave like str() when applied to non-string/buffer
226 objects.
227
Martin v. Löwis2777c022001-09-19 13:47:32 +0000228- PyFile_WriteObject now passes Unicode object to the file's write
229 method. As a result, all file-like object which may be the target
230 of a print statement must support Unicode objects, i.e. they must
231 at least convert them into ASCII strings.
232
Guido van Rossum624c8af2001-09-18 15:21:04 +0000233- Thread scheduling on Solaris should be improved; it is no longer
234 necessary to insert a small sleep at the start of a thread in order
235 to let other runnable threads be scheduled.
236
Tim Petersb07352e2001-09-08 01:25:47 +0000237Library
238
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000239- StringIO.StringIO instances and cStringIO.StringIO instances support
240 read character buffer compatible objects for their .write() methods.
241 These objects are converted to strings and then handled as such
242 by the instances.
243
Barry Warsaw2f600732001-09-24 04:28:10 +0000244- The "email" package has been added. This is basically a port of the
245 mimelib package <http://sf.net/projects/mimelib> with API changes
246 and some implementations updated to use iterators and generators.
247
Tim Peters8a9c2842001-09-22 21:30:22 +0000248- difflib.ndiff() and difflib.Differ.compare() are generators now. This
249 restores the ability of Tools/scripts/ndiff.py to start producing output
250 before the entire comparison is complete.
251
Barry Warsaw58b072d2001-09-22 04:44:21 +0000252- StringIO.StringIO instances and cStringIO.StringIO instances support
253 iteration just like file objects (i.e. their .readline() method is
254 called for each iteration until it returns an empty string).
255
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000256- The codecs module has grown four new helper APIs to access
257 builtin codecs: getencoder(), getdecoder(), getreader(),
258 getwriter().
259
Guido van Rossum624c8af2001-09-18 15:21:04 +0000260- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
261 simplifies writing XML RPC servers.
262
Barry Warsaw647d5e82001-09-28 17:01:02 +0000263- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000264 after interpretation of symbolic links. On non-Unix systems, this
265 is an alias for os.path.abspath().
266
Tim Peters16a77ad2001-09-08 04:00:12 +0000267- operator.indexOf() (PySequence_Index() in the C API) now works with any
268 iterable object.
269
Guido van Rossum624c8af2001-09-18 15:21:04 +0000270- smtplib now supports various authentication and security features of
271 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000272
Guido van Rossum624c8af2001-09-18 15:21:04 +0000273- hmac: a new module implementing keyed hashing for message
274 authentication.
275
276- mimetypes now recognizes more extensions and file types. At the
277 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000278
Guido van Rossum624c8af2001-09-18 15:21:04 +0000279- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000280 Python 2.2 bytecode generation. It has also been promoted from a
281 Tool to a standard library package. (Tools/compiler still exists as
282 a sample driver.)
283
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000284Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000285
Tim Petersb07352e2001-09-08 01:25:47 +0000286Build
287
Guido van Rossum624c8af2001-09-18 15:21:04 +0000288- Large file support (LFS) is now automatic when the platform supports
289 it; no more manual configuration tweaks are needed. On Linux, at
290 least, it's possible to have a system whose C library supports large
291 files but whose kernel doesn't; in this case, large file support is
292 still enabled but doesn't do you any good unless you upgrade your
293 kernel or share your Python executable with another system whose
294 kernel has large file support.
295
296- The configure script now supplies plausible defaults in a
297 cross-compilation environment. This doesn't mean that the supplied
298 values are always correct, or that cross-compilation now works
299 flawlessly -- but it's a first step (and it shuts up most of
300 autoconf's warnings about AC_TRY_RUN).
301
302- The Unix build is now a bit less chatty, courtesy of the parser
303 generator. The build is completely silent (except for errors) when
304 using "make -s", thanks to a -q option to setup.py.
305
Tim Petersb07352e2001-09-08 01:25:47 +0000306C API
307
Guido van Rossum624c8af2001-09-18 15:21:04 +0000308- The "structmember" API now supports some new flag bits to deny read
309 and/or write access to attributes in restricted execution mode.
310
Tim Petersb07352e2001-09-08 01:25:47 +0000311New platforms
312
Guido van Rossum624c8af2001-09-18 15:21:04 +0000313- Compaq's iPAQ handheld, running the "familiar" Linux distribution
314 (http://familiar.handhelds.org).
315
Tim Petersb07352e2001-09-08 01:25:47 +0000316Tests
317
Tim Peters8a9c2842001-09-22 21:30:22 +0000318- The "classic" standard tests, which work by comparing stdout to
319 an expected-output file under Lib/test/output/, no longer stop at
320 the first mismatch. Instead the test is run to completion, and a
321 variant of ndiff-style comparison is used to report all differences.
322 This is much easier to understand than the previous style of reporting.
323
324- The unittest-based standard tests now use regrtest's test_main()
325 convention, instead of running as a side-effect of merely being
326 imported. This allows these tests to be run in more natural and
327 flexible ways as unittests, outside the regrtest framework.
328
329- regrtest.py is much better integrated with unittest and doctest now,
330 especially in regard to reporting errors.
331
Tim Petersb07352e2001-09-08 01:25:47 +0000332Windows
333
Guido van Rossum624c8af2001-09-18 15:21:04 +0000334- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000335 that support it (NTFS under Windows 2000). See "What's New in
336 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000337
Tim Petersb07352e2001-09-08 01:25:47 +0000338
Tim Petersedc99312001-08-22 21:36:50 +0000339What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000340Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000341===========================
342
343Core
344
Tim Peters9fffa3e2001-09-04 05:14:19 +0000345- Conversion of long to float now raises OverflowError if the long is too
346 big to represent as a C double.
347
Tim Peters32f453e2001-09-03 08:35:41 +0000348- The 3-argument builtin pow() no longer allows a third non-None argument
349 if either of the first two arguments is a float, or if both are of
350 integer types and the second argument is negative (in which latter case
351 the arguments are converted to float, so this is really the same
352 restriction).
353
Tim Peters5d2b77c2001-09-03 05:47:38 +0000354- The builtin dir() now returns more information, and sometimes much
355 more, generally naming all attributes of an object, and all attributes
356 reachable from the object via its class, and from its class's base
357 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
358 an empty list. In 2.2a3,
359
360 >>> dir([])
361 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
362 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
363 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
364 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
365 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
366 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
367 'reverse', 'sort']
368
369 dir(module) continues to return only the module's attributes, though.
370
Tim Petersbdee63f2001-09-02 03:40:59 +0000371- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000372 than raising OverflowError. This is a partial implementation of PEP
373 237. You can use -Wdefault::OverflowWarning to enable a warning for
374 this situation, and -Werror::OverflowWarning to revert to the old
375 OverflowError exception.
376
Guido van Rossum61c345f2001-09-04 03:26:15 +0000377- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000378 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000379 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
380 -Qold, meaning the / operator has its classic meaning and no
381 warnings are issued. Using -Qwarn issues a run-time warning about
382 all uses of classic division for int and long arguments; -Qwarnall
383 also warns about classic division for float and complex arguments
384 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
385 new division by default, but only in the __main__ module. You can
386 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
387 __main__ module new division, and warns about classic division
388 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000389
Tim Petersbdee63f2001-09-02 03:40:59 +0000390- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000391 long, float, str, unicode, and tuple. (The types complex, list and
392 dictionary can also be subclassed; this was introduced earlier.)
393 Note that restrictions apply when subclassing immutable built-in
394 types: you can only affect the value of the instance by overloading
395 __new__. You can add mutable attributes, and the subclass instances
396 will have a __dict__ attribute, but you cannot change the "value"
397 (as implemented by the base class) of an immutable subclass instance
398 once it is created.
399
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000400- The dictionary constructor now takes an optional argument, a
401 mapping-like object, and initializes the dictionary from its
402 (key, value) pairs.
403
Tim Petersbdee63f2001-09-02 03:40:59 +0000404- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000405 "cooperative super calls" in a multiple inheritance setting. For an
406 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
407
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000408- A new built-in type, property, has been added. This enables the
409 creation of "properties". These are attributes implemented by
410 getter and setter functions (or only one of these for read-only or
411 write-only attributes), without the need to override __getattr__.
412 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000413
Tim Petersbdee63f2001-09-02 03:40:59 +0000414- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000415 liberalized, to allow leading zeroes. Examples of literals now
416 legal that were SyntaxErrors before:
417
418 00.0 0e3 0100j 07.5 00000000000000000008.
419
Tim Petersbdee63f2001-09-02 03:40:59 +0000420- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000421 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
422
Tim Petersedc99312001-08-22 21:36:50 +0000423Library
424
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000425- telnetlib includes symbolic names for the options, and support for
426 setting an option negotiation callback.
427
Tim Petersa40c7932001-09-05 22:36:56 +0000428- The new C standard no longer requires that math libraries set errno to
429 ERANGE on overflow. For platform libraries that exploit this new
430 freedom, Python's overflow-checking was wholly broken. A new overflow-
431 checking scheme attempts to repair that, but may not be reliable on all
432 platforms (C doesn't seem to provide anything both useful and portable
433 in this area anymore).
434
Martin v. Löwis44f86962001-09-05 13:44:54 +0000435- Asynchronous timeout actions are available through the new class
436 threading.Timer.
437
Tim Peters78526162001-09-05 00:53:45 +0000438- math.log and math.log10 now return sensible results for even huge
439 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
440
Tim Petersbdee63f2001-09-02 03:40:59 +0000441- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000442 currently held. See the docs for the imp module.
443
Tim Petersbdee63f2001-09-02 03:40:59 +0000444- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000445 dumps containing ints written on platforms where Python ints are 8 bytes.
446 When read on a box where Python ints are 4 bytes, such values are
447 converted to Python longs.
448
Tim Petersbdee63f2001-09-02 03:40:59 +0000449- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000450 code objects is no longer allowed. This plugs a security hole.
451
Steve Purcell6091cd62001-09-06 16:05:17 +0000452- unittest.TestResult instances no longer store references to tracebacks
453 generated by test failures. This prevents unexpected dangling references
454 to objects that should be garbage collected between tests.
455
Tim Petersedc99312001-08-22 21:36:50 +0000456Tools
457
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000458- Tools/scripts/fixdiv.py has been added which can be used to fix
459 division operators as per PEP 238.
460
Tim Petersedc99312001-08-22 21:36:50 +0000461Build
462
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000463- If you are an adventurous person using Mac OS X you may want to look at
464 Mac/OSX. There is a Makefile there that will build Python as a real Mac
465 application, which can be used for experimenting with Carbon or Cocoa.
466 Discussion of this on pythonmac-sig, please.
467
Tim Peters7eea37e2001-09-04 22:08:56 +0000468C API
469
470- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000471
Tim Peters9fffa3e2001-09-04 05:14:19 +0000472- Note that PyLong_AsDouble can fail! This has always been true, but no
473 callers checked for it. It's more likely to fail now, because overflow
474 errors are properly detected now. The proper way to check:
475
476 double x = PyLong_AsDouble(some_long_object);
477 if (x == -1.0 && PyErr_Occurred()) {
478 /* The conversion failed. */
479 }
480
Tim Petersbdee63f2001-09-02 03:40:59 +0000481- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000482 compile but will not participate in GC. To upgrade an extension
483 module:
484
485 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000486
Neil Schemenauer4042c692001-08-30 15:38:01 +0000487 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
488 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000489
Neil Schemenauer4042c692001-08-30 15:38:01 +0000490 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
491 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000492
Neil Schemenauer4042c692001-08-30 15:38:01 +0000493 - remove PyGC_HEAD_SIZE from object size calculations
494
495 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
496
Tim Petersbdee63f2001-09-02 03:40:59 +0000497- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000498 These can be used safely to construct string objects from a
499 sprintf-style format string (similar to the format string supported
500 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000501
Tim Petersedc99312001-08-22 21:36:50 +0000502New platforms
503
Tim Petersb7da0902001-09-02 23:01:43 +0000504- Stephen Hansen contributed patches sufficient to get a clean compile
505 under Borland C (Windows), but he reports problems running it and ran
506 out of time to complete the port. Volunteers? Expect a MemoryError
507 when importing the types module; this is probably shallow, and
508 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000509
Tim Petersedc99312001-08-22 21:36:50 +0000510Tests
511
512Windows
513
Tim Peters6e13a562001-09-06 00:32:15 +0000514- Large file support is now enabled on Win32 platforms as well as on
515 Win64. This means that, for example, you can use f.tell() and f.seek()
516 to manipulate files larger than 2 gigabytes (provided you have enough
517 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000518 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
519 filesize limit, and large file support makes no difference there.
520 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
521 NTFS has no practical limit on file size, and files of any size can be
522 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000523
Tim Petersbdee63f2001-09-02 03:40:59 +0000524- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000525 points to command.com (patch from Brian Quinlan).
526
Tim Petersedc99312001-08-22 21:36:50 +0000527
Tim Peters20f51a72001-07-21 02:31:40 +0000528What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000529Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000530===========================
531
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000532Build
533
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000534- Tim Peters developed a brand new Windows installer using Wise 8.1,
535 generously donated to us by Wise Solutions.
536
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000537- configure supports a new option --enable-unicode, with the values
538 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
539 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000540
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000541- A new configure option --enable-framework builds a Mac OS X framework,
542 which "make frameworkinstall" will install. This provides a starting
543 point for more mac-like functionality, join pythonmac-sig@python.org
544 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000545
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000546- The NeXT platform is no longer supported.
547
548- The `new' module is now statically linked.
549
Tim Peters0afb6092001-08-15 06:06:44 +0000550Tools
551
552- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000553 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000554 the module docstring for details.
555
Tim Peters20f51a72001-07-21 02:31:40 +0000556Tests
557
Tim Peters5e824c32001-08-12 22:25:01 +0000558- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000559 platforms, allowing to give clearer test result output. regrtest
560 also has optional --use/-u switch to run normally disabled tests
561 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000562
Tim Peters20f51a72001-07-21 02:31:40 +0000563- Several new tests in the standard test suite, with special thanks to
564 Nick Mathewson.
565
566Core
567
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000568- The floor division operator // has been added as outlined in PEP
569 238. The / operator still provides classic division (and will until
570 Python 3.0) unless "from __future__ import division" is included, in
571 which case the / operator will provide true division. The operator
572 module provides truediv() and floordiv() functions. Augmented
573 assignment variants are included, as are the equivalent overloadable
574 methods and C API methods. See the PEP for a full discussion:
575 <http://python.sf.net/peps/pep-0238.html>
576
Tim Peters6cd6a822001-08-17 22:11:27 +0000577- Future statements are now effective in simulated interactive shells
578 (like IDLE). This should "just work" by magic, but read Michael
579 Hudson's "Future statements in simulated shells" PEP 264 for full
580 details: <http://python.sf.net/peps/pep-0264.html>.
581
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000582- The type/class unification (PEP 252-253) was integrated into the
583 trunk and is not so tentative any more (the exact specification of
584 some features is still tentative). A lot of work has done on fixing
585 bugs and adding robustness and features (performance still has to
586 come a long way).
587
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000588- Warnings about a mismatch in the Python API during extension import
589 now use the Python warning framework (which makes it possible to
590 write filters for these warnings).
591
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000592- A function's __dict__ (aka func_dict) will now always be a
593 dictionary. It used to be possible to delete it or set it to None,
594 but now both actions raise TypeErrors. It is still legal to set it
595 to a dictionary object. Getting func.__dict__ before any attributes
596 have been assigned now returns an empty dictionary instead of None.
597
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000598- A new command line option, -E, was added which disables the use of
599 all environment variables, or at least those that are specifically
600 significant to Python. Usually those have a name starting with
601 "PYTHON". This was used to fix a problem where the tests fail if
602 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
603 older distribution.
604
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000605Library
606
Tim Peters5e824c32001-08-12 22:25:01 +0000607- New class Differ and new functions ndiff() and restore() in difflib.py.
608 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000609 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000610
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000611- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
612 value using the minimal quoting required for the value; more
613 reliable than using xml.sax.saxutils.escape() for attribute values.
614
615- Readline completion support for cmd.Cmd was added.
616
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000617- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
618
619- Added function threading.BoundedSemaphore()
620
621- Added Ka-Ping Yee's cgitb.py module.
622
623- The `new' module now exposes the CO_xxx flags.
624
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000625New platforms
626
627C API
628
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000629- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
630 which provide a cross-platform implementations for the
631 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
632 the standard sprintf() and vsprintf() C lib APIs, these versions
633 apply bounds checking on the used buffer which enhances protection
634 against buffer overruns.
635
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000636- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000637 and extensions using different Unicode widths is rendered next to
638 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000639 will result in an ImportError. Unicode extensions writers must make
640 sure to check the Unicode width compatibility in their extensions by
641 using at least one of the mangled Unicode APIs in the extension.
642
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000643- Two new flags METH_NOARGS and METH_O are available in method definition
644 tables to simplify implementation of methods with no arguments and a
645 single untyped argument. Calling such methods is more efficient than
646 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
647 deprecated.
648
Tim Petersc1731372001-08-04 08:12:36 +0000649Windows
650
651- "import module" now compiles module.pyw if it exists and nothing else
652 relevant is found.
653
Tim Peters20f51a72001-07-21 02:31:40 +0000654
Guido van Rossum55a78992001-07-17 17:22:32 +0000655What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +0000656===========================
657
658Core
Tim Petersa814db52001-05-14 07:05:58 +0000659
Tim Peters6d6c1a32001-08-02 04:15:00 +0000660- TENTATIVELY, a large amount of code implementing much of what's
661 described in PEP 252 (Making Types Look More Like Classes) and PEP
662 253 (Subtyping Built-in Types) was added. This will be released
663 with Python 2.2a1. Documentation will be provided separately
664 through http://www.python.org/2.2/. The purpose of releasing this
665 with Python 2.2a1 is to test backwards compatibility. It is
666 possible, though not likely, that a decision is made not to release
667 this code as part of 2.2 final, if any serious backwards
668 incompapatibilities are found during alpha testing that cannot be
669 repaired.
670
Guido van Rossum55a78992001-07-17 17:22:32 +0000671- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000672 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000673 more 'yield' statements. See PEP 255. Since this adds a new
674 keyword to the language, this feature must be enabled by including a
675 future statement: "from __future__ import generators" (see PEP 236).
676 Generators will become a standard feature in a future release
677 (probably 2.3). Without this future statement, 'yield' remains an
678 ordinary identifier, but a warning is issued each time it is used.
679 (These warnings currently don't conform to the warnings framework of
680 PEP 230; we intend to fix this in 2.2a2.)
681
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000682- The UTF-16 codec was modified to be more RFC compliant. It will now
683 only remove BOM characters at the start of the string and then
684 only if running in native mode (UTF-16-LE and -BE won't remove a
685 leading BMO character).
686
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000687- Strings now have a new method .decode() to complement the already
688 existing .encode() method. These two methods provide direct access
689 to the corresponding decoders and encoders of the registered codecs.
690
691 To enhance the usability of the .encode() method, the special
692 casing of Unicode object return values was dropped (Unicode objects
693 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000694
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000695 Both methods will now return whatever the codec in charge of the
696 requested encoding returns as object, e.g. Unicode codecs will
697 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
698 will return u"äöü"). This enables codec writer to create codecs
699 for various simple to use conversions.
700
701 New codecs were added to demonstrate these new features (the .encode()
702 and .decode() columns indicate the type of the returned objects):
703
704 Name | .encode() | .decode() | Description
705 ----------------------------------------------------------------------
706 uu | string | string | UU codec (e.g. for email)
707 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000708 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000709 zlib | string | string | zlib compression
710 hex | string | string | 2-byte hex codec
711 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
712
Mark Hammond2a0af792001-05-14 03:09:36 +0000713- Some operating systems now support the concept of a default Unicode
714 encoding for file system operations. Notably, Windows supports 'mbcs'
715 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000716 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000717 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000718
719 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000720 functions that return filenames (such as os.listdir()) to return Python
721 string objects pre-encoded using the default file system encoding for
722 the platform. As this encoding is likely to be different from Python's
723 default encoding, converting this name to a Unicode object before passing
724 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000725 would attempt to use its default encoding (generally ASCII) rather than
726 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000727
Tim Petersa814db52001-05-14 07:05:58 +0000728 In general, this change simply removes surprises when working with
729 Unicode and the file system, making these operations work as you expect,
730 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000731 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000732
Tim Peters61dff2b2001-05-08 15:43:37 +0000733- Float (and complex) literals in source code were evaluated to full
734 precision only when running from a .py file; the same code loaded from a
735 .pyc (or .pyo) file could suffer numeric differences starting at about the
736 12th significant decimal digit. For example, on a machine with IEEE-754
737 floating arithmetic,
738
739 x = 9007199254740992.0
740 print long(x)
741
742 printed 9007199254740992 if run directly from .py, but 9007199254740000
743 if from a compiled (.pyc or .pyo) file. This was due to marshal using
744 str(float) instead of repr(float) when building code objects. marshal
745 now uses repr(float) instead, which should reproduce floats to full
746 machine precision (assuming the platform C float<->string I/O conversion
747 functions are of good quality).
748
749 This may cause floating-point results to change in some cases, and
750 usually for the better, but may also cause numerically unstable
751 algorithms to break.
752
Tim Peters2f228e72001-05-13 00:19:31 +0000753- The implementation of dicts suffers fewer collisions, which has speed
754 benefits. However, the order in which dict entries appear in dict.keys(),
755 dict.values() and dict.items() may differ from previous releases for a
756 given dict. Nothing is defined about this order, so no program should
757 rely on it. Nevertheless, it's easy to write test cases that rely on the
758 order by accident, typically because of printing the str() or repr() of a
759 dict to an "expected results" file. See Lib/test/test_support.py's new
760 sortdict(dict) function for a simple way to display a dict in sorted
761 order.
762
Tim Peters7a3bfc32001-06-12 01:22:22 +0000763- Many other small changes to dicts were made, resulting in faster
764 operation along the most common code paths.
765
Guido van Rossum10315822001-05-01 20:54:30 +0000766- Dictionary objects now support the "in" operator: "x in dict" means
767 the same as dict.has_key(x).
768
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000769- The update() method of dictionaries now accepts generic mapping
770 objects. Specifically the argument object must support the .keys()
771 and __getitem__() methods. This allows you to say, for example,
772 {}.update(UserDict())
773
Guido van Rossum10315822001-05-01 20:54:30 +0000774- Iterators were added; this is a generalized way of providing values
775 to a for loop. See PEP 234. There's a new built-in function iter()
776 to return an iterator. There's a new protocol to get the next value
777 from an iterator using the next() method (in Python) or the
778 tp_iternext slot (in C). There's a new protocol to get iterators
779 using the __iter__() method (in Python) or the tp_iter slot (in C).
780 Iterating (i.e. a for loop) over a dictionary generates its keys.
781 Iterating over a file generates its lines.
782
Tim Petersf553f892001-05-01 20:45:31 +0000783- The following functions were generalized to work nicely with iterator
784 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000785 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000786 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
787 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000788 join() method of strings
789 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000790 'x in y' and 'x not in y' (PySequence_Contains() in C API)
791 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000792 right-hand side of assignment statements with multiple targets, such as
793 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000794
Tim Petersd85e1022001-05-11 21:51:48 +0000795- Accessing module attributes is significantly faster (for example,
796 random.random or os.path or yourPythonModule.yourAttribute).
797
Tim Peterse63415e2001-05-08 04:38:29 +0000798- Comparing dictionary objects via == and != is faster, and now works even
799 if the keys and values don't support comparisons other than ==.
800
Tim Peters95bf9392001-05-10 08:32:44 +0000801- Comparing dictionaries in ways other than == and != is slower: there were
802 insecurities in the dict comparison implementation that could cause Python
803 to crash if the element comparison routines for the dict keys and/or
804 values mutated the dicts. Making the code bulletproof slowed it down.
805
Tim Peterseb28ef22001-06-02 05:27:19 +0000806- Collisions in dicts are resolved via a new approach, which can help
807 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000808 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000809 faster now. Thanks to Christian Tismer for pointing out the cause and
810 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000811
Tim Peters52e155e2001-06-16 05:42:57 +0000812- repr() is much faster for large containers (dict, list, tuple).
813
814
Tim Petersa814db52001-05-14 07:05:58 +0000815Library
816
Fred Drake960fdf92001-07-20 18:38:26 +0000817- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
818 were added to the string module. These a locale-indenpendent
819 constants, unlike letters, lowercase, and uppercase. These are now
820 use in appropriate locations in the standard library.
821
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000822- The flags used in dlopen calls can now be configured using
823 sys.setdlopenflags and queried using sys.getdlopenflags.
824
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000825- Fredrik Lundh's xmlrpclib is now a standard library module. This
826 provides full client-side XML-RPC support. In addition,
827 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
828 one asyncore-based). Thanks to Eric Raymond for the documentation.
829
Guido van Rossum643d3912001-07-05 14:46:25 +0000830- The xrange() object is simplified: it no longer supports slicing,
831 repetition, comparisons, efficient 'in' checking, the tolist()
832 method, or the start, stop and step attributes. See PEP 260.
833
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000834- A new function fnmatch.filter to filter lists of file names was added.
835
Barry Warsawffd674d2001-05-22 16:00:10 +0000836- calendar.py uses month and day names based on the current locale.
837
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000838- strop is now *really* obsolete (this was announced before with 1.6),
839 and issues DeprecationWarning when used (except for the four items
840 that are still imported into string.py).
841
Tim Petersa814db52001-05-14 07:05:58 +0000842- Cookie.py now sorts key+value pairs by key in output strings.
843
844- pprint.isrecursive(object) didn't correctly identify recursive objects.
845 Now it does.
846
Tim Peters95b3f782001-05-14 18:39:41 +0000847- pprint functions now much faster for large containers (tuple, list, dict).
848
Tim Peters7b9542a2001-06-10 23:40:19 +0000849- New 'q' and 'Q' format codes in the struct module, corresponding to C
850 types "long long" and "unsigned long long" (on Windows, __int64). In
851 native mode, these can be used only when the platform C compiler supports
852 these types (when HAVE_LONG_LONG is #define'd by the Python config
853 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000854 In standard mode, 'q' and 'Q' are supported on all platforms, and are
855 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000856
Guido van Rossum83213cc2001-06-12 16:48:52 +0000857- The site module installs a new built-in function 'help' that invokes
858 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
859 it displays a message reminding the user to use 'help()' or
860 'help(object)'.
861
Tim Petersa814db52001-05-14 07:05:58 +0000862Tests
863
864- New test_mutants.py runs dict comparisons where the key and value
865 comparison operators mutute the dicts randomly during comparison. This
866 rapidly causes Python to crash under earlier releases (not for the faint
867 of heart: it can also cause Win9x to freeze or reboot!).
868
869- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000870 pprint.isreadable() return sensible results. Also verifies that simple
871 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000872
Tim Peters4324aa32001-05-28 22:30:08 +0000873C API
874
875- Removed the unused last_is_sticky argument from the internal
876 _PyTuple_Resize(). If this affects you, you were cheating.
877
878
Guido van Rossum55a78992001-07-17 17:22:32 +0000879======================================================================
880
881
Guido van Rossumffe13be2001-04-16 18:46:45 +0000882What's New in Python 2.1 (final)?
883=================================
884
885We only changed a few things since the last release candidate, all in
886Python library code:
887
888- A bug in the locale module was fixed that affected locales which
889 define no grouping for numeric formatting.
890
891- A few bugs in the weakref module's implementations of weak
892 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
893 and the test suite was updated to check for these bugs.
894
895- An old bug in the os.path.walk() function (introduced in Python
896 2.0!) was fixed: a non-existent file would cause an exception
897 instead of being ignored.
898
899- Fixed a few bugs in the new symtable module found by Neil Norwitz's
900 PyChecker.
901
902
Guido van Rossum5b08f132001-04-16 02:05:23 +0000903What's New in Python 2.1c2?
904===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000905
Guido van Rossum5b08f132001-04-16 02:05:23 +0000906A flurry of small changes, and one showstopper fixed in the nick of
907time made it necessary to release another release candidate. The list
908here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000909
Guido van Rossum5b08f132001-04-16 02:05:23 +0000910Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000911
Guido van Rossum5b08f132001-04-16 02:05:23 +0000912- Tim discovered a nasty bug in the dictionary code, caused by
913 PyDict_Next() calling dict_resize(), and the GC code's use of
914 PyDict_Next() violating an assumption in dict_items(). This was
915 fixed with considerable amounts of band-aid, but the net effect is a
916 saner and more robust implementation.
917
918- Made a bunch of symbols static that were accidentally global.
919
920Build and Ports
921
922- The setup.py script didn't check for a new enough version of zlib
923 (1.1.3 is needed). Now it does.
924
925- Changed "make clean" target to also remove shared libraries.
926
927- Added a more general warning about the SGI Irix optimizer to README.
928
929Library
930
931- Fix a bug in urllib.basejoin("http://host", "../file.html") which
932 omitted the slash between host and file.html.
933
934- The mailbox module's _Mailbox class contained a completely broken
935 and undocumented seek() method. Ripped it out.
936
937- Fixed a bunch of typos in various library modules (urllib2, smtpd,
938 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
939
940- Fixed a few last-minute bugs in unittest.
941
942Extensions
943
944- Reverted the patch to the OpenSSL code in socketmodule.c to support
945 RAND_status() and the EGD, and the subsequent patch that tried to
946 fix it for pre-0.9.5 versions; the problem with the patch is that on
947 some systems it issues a warning whenever socket is imported, and
948 that's unacceptable.
949
950Tests
951
952- Fixed the pickle tests to work with "import test.test_pickle".
953
954- Tweaked test_locale.py to actually run the test Windows.
955
956- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
957 not "wb" (which is not a valid mode at all).
958
959- Fix pstats browser crashes. Import readline if it exists to make
960 the user interface nicer.
961
962- Add "import thread" to the top of test modules that import the
963 threading module (test_asynchat and test_threadedtempfile). This
964 prevents test failures caused by a broken threading module resulting
965 from a previously caught failed import.
966
967- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
968 needed on some platforms (e.g. Solaris 8) when the tests are run
969 twice in succession.
970
971- Skip rather than fail test_sunaudiodev if no audio device is found.
972
973
974What's New in Python 2.1c1?
975===========================
976
977This list was significantly updated when 2.1c2 was released; the 2.1c1
978release didn't mention most changes that were actually part of 2.1c1:
979
980Legal
981
982- Copyright was assigned to the Python Software Foundation (PSF) and a
983 PSF license (very similar to the CNRI license) was added.
984
985- The CNRI copyright notice was updated to include 2001.
986
987Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000988
Guido van Rossumc9932722001-04-12 02:31:27 +0000989- After a public outcry, assignment to __debug__ is no longer illegal;
990 instead, a warning is issued. It will become illegal in 2.2.
991
Guido van Rossum5b08f132001-04-16 02:05:23 +0000992- Fixed a core dump with "%#x" % 0, and changed the semantics so that
993 "%#x" now always prepends "0x", even if the value is zero.
994
995- Fixed some nits in the bytecode compiler.
996
997- Fixed core dumps when calling certain kinds of non-functions.
998
999- Fixed various core dumps caused by reference count bugs.
1000
1001Build and Ports
1002
1003- Use INSTALL_SCRIPT to install script files.
1004
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001005- New port: SCO Unixware 7, by Billy G. Allie.
1006
Guido van Rossum5b08f132001-04-16 02:05:23 +00001007- Updated RISCOS port.
1008
1009- Updated BeOS port and notes.
1010
1011- Various other porting problems resolved.
1012
1013Library
1014
1015- The TERMIOS and SOCKET modules are now truly obsolete and
1016 unnecessary. Their symbols are incorporated in the termios and
1017 socket modules.
1018
1019- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1020 better tests for pickling.
1021
1022- threading: make Condition.wait() robust against KeyboardInterrupt.
1023
1024- zipfile: add support to zipfile to support opening an archive
1025 represented by an open file rather than a file name. Fix bug where
1026 the archive was not properly closed. Fixed a bug in this bugfix
1027 where flush() was called for a read-only file.
1028
1029- imputil: added an uninstall() method to the ImportManager.
1030
1031- Canvas: fixed bugs in lower() and tkraise() methods.
1032
1033- SocketServer: API change (added overridable close_request() method)
1034 so that the TCP server can explicitly close the request.
1035
1036- pstats: Eric Raymond added a simple interactive statistics browser,
1037 invoked when the module is run as a script.
1038
1039- locale: fixed a problem in format().
1040
1041- webbrowser: made it work when the BROWSER environment variable has a
1042 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1043 KDE 2. Fixed some other nits.
1044
1045- unittest: changes to allow using a different exception than
1046 AssertionError, and added a few more function aliases. Some other
1047 small changes.
1048
1049- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1050
1051- asynchat: fixed a critical bug in asynchat that slipped through the
1052 2.1b2 release. Fixed another rare bug.
1053
1054- Fix some unqualified except: clauses (always a bad code example).
1055
1056XML
1057
1058- pyexpat: new API get_version_string().
1059
1060- Fixed some minidom bugs.
1061
1062Extensions
1063
1064- Fixed a core dump in _weakref. Removed the weakref.mapping()
1065 function (it adds nothing to the API).
1066
1067- Rationalized the use of header files in the readline module, to make
1068 it compile (albeit with some warnings) with the very recent readline
1069 4.2, without breaking for earlier versions.
1070
1071- Hopefully fixed a buffering problem in linuxaudiodev.
1072
1073- Attempted a fix to make the OpenSSL support in the socket module
1074 work again with pre-0.9.5 versions of OpenSSL.
1075
1076Tests
1077
1078- Added a test case for asynchat and asyncore.
1079
1080- Removed coupling between tests where one test failing could break
1081 another.
1082
1083Tools
1084
1085- Ping added an interactive help browser to pydoc, fixed some nits
1086 in the rest of the pydoc code, and added some features to his
1087 inspect module.
1088
1089- An updated python-mode.el version 4.1 which integrates Ken
1090 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1091 much nicer in XEmacs and Emacs. When stepping through your program
1092 with pdb, in either the shell window or the *Python* window, the
1093 source file and line will be tracked by an arrow. Very cool!
1094
1095- IDLE: syntax warnings in interactive mode are changed into errors.
1096
1097- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001098 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001099
1100- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001101
Barry Warsaw11e89c72001-04-11 20:37:57 +00001102
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001103What's New in Python 2.1 beta 2?
1104================================
1105
Guido van Rossum053ae352001-03-22 14:17:21 +00001106(Unlisted are many fixed bugs, more documentation, etc.)
1107
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001108Core language, builtins, and interpreter
1109
Guido van Rossum053ae352001-03-22 14:17:21 +00001110- The nested scopes work (enabled by "from __future__ import
1111 nested_scopes") is completed; in particular, the future now extends
1112 into code executed through exec, eval() and execfile(), and into the
1113 interactive interpreter.
1114
1115- When calling a base class method (e.g. BaseClass.__init__(self)),
1116 this is now allowed even if self is not strictly spoken a class
1117 instance (e.g. when using metaclasses or the Don Beaudry hook).
1118
1119- Slice objects are now comparable but not hashable; this prevents
1120 dict[:] from being accepted but meaningless.
1121
1122- Complex division is now calculated using less braindead algorithms.
1123 This doesn't change semantics except it's more likely to give useful
1124 results in extreme cases. Complex repr() now uses full precision
1125 like float repr().
1126
1127- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1128
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001129- It is illegal to assign to the name __debug__, which is set when the
1130 interpreter starts. It is effectively a compile-time constant.
1131
1132- A warning will be issued if a global statement for a variable
1133 follows a use or assignment of that variable.
1134
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001135Standard library
1136
Guido van Rossum053ae352001-03-22 14:17:21 +00001137- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1138 inspired by JUnit), is now part of the standard library. You now
1139 have a choice of two testing frameworks: unittest requires you to
1140 write testcases as separate code, doctest gathers them from
1141 docstrings. Both approaches have their advantages and
1142 disadvantages.
1143
1144- A new module Tix was added, which wraps the Tix extension library
1145 for Tk. With that module, it is not necessary to statically link
1146 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1147 require" command. See Demo/tix/.
1148
1149- tzparse.py is now obsolete.
1150
1151- In gzip.py, the seek() and tell() methods are removed -- they were
1152 non-functional anyway, and it's better if callers can test for their
1153 existence with hasattr().
1154
1155Python/C API
1156
1157- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1158 that's already in the dictionary during a PyDict_Next() iteration.
1159 This used to fail occasionally when a dictionary resize operation
1160 could be triggered that would rehash all the keys. All other
1161 modifications to the dictionary are still off-limits during a
1162 PyDict_Next() iteration!
1163
1164- New extended APIs related to passing compiler variables around.
1165
1166- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1167 implement isinstance() and issubclass().
1168
1169- Py_BuildValue() now has a "D" conversion to create a Python complex
1170 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001171
Fred Drake4e262a92001-03-22 18:26:47 +00001172- Extensions types which support weak references must now set the
1173 field allocated for the weak reference machinery to NULL themselves;
1174 this is done to avoid the cost of checking each object for having a
1175 weakly referencable type in PyObject_INIT(), since most types are
1176 not weakly referencable.
1177
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001178- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1179 free variables and cell variables to and from the frame's f_locals.
1180
1181- Variants of several functions defined in pythonrun.h have been added
1182 to support the nested_scopes future statement. The variants all end
1183 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1184 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1185 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001186 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001187
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001188Distutils
1189
1190- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1191 into the release tree.
1192
Tim Peters0e57abf2001-05-02 07:39:38 +00001193- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001194 (an uninstaller, more customization of the installer's display)
1195
1196- from Jack Jansen: added Mac-specific code to generate a dialog for
1197 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001198 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001199 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001200
1201- added 'platforms' and 'keywords' to the set of metadata that can be
1202 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001203
1204- applied patches from Jason Tishler to make the compiler class work with
1205 Cygwin.
1206
1207
Tim Peters2fe289a2001-03-01 22:19:38 +00001208What's New in Python 2.1 beta 1?
1209================================
Tim Petersd66595f2001-02-04 03:09:53 +00001210
1211Core language, builtins, and interpreter
1212
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001213- Following an outcry from the community about the amount of code
1214 broken by the nested scopes feature introduced in 2.1a2, we decided
1215 to make this feature optional, and to wait until Python 2.2 (or at
1216 least 6 months) to make it standard. The option can be enabled on a
1217 per-module basis by adding "from __future__ import nested_scopes" at
1218 the beginning of a module (before any other statements, but after
1219 comments and an optional docstring). See PEP 236 (Back to the
1220 __future__) for a description of the __future__ statement. PEP 227
1221 (Statically Nested Scopes) has been updated to reflect this change,
1222 and to clarify the semantics in a number of endcases.
1223
1224- The nested scopes code, when enabled, has been hardened, and most
1225 bugs and memory leaks in it have been fixed.
1226
1227- Compile-time warnings are now generated for a number of conditions
1228 that will break or change in meaning when nested scopes are enabled:
1229
1230 - Using "from...import *" or "exec" without in-clause in a function
1231 scope that also defines a lambda or nested function with one or
1232 more free (non-local) variables. The presence of the import* or
1233 bare exec makes it impossible for the compiler to determine the
1234 exact set of local variables in the outer scope, which makes it
1235 impossible to determine the bindings for free variables in the
1236 inner scope. To avoid the warning about import *, change it into
1237 an import of explicitly name object, or move the import* statement
1238 to the global scope; to avoid the warning about bare exec, use
1239 exec...in... (a good idea anyway -- there's a possibility that
1240 bare exec will be deprecated in the future).
1241
1242 - Use of a global variable in a nested scope with the same name as a
1243 local variable in a surrounding scope. This will change in
1244 meaning with nested scopes: the name in the inner scope will
1245 reference the variable in the outer scope rather than the global
1246 of the same name. To avoid the warning, either rename the outer
1247 variable, or use a global statement in the inner function.
1248
Neil Schemenauera35c6882001-02-27 04:45:05 +00001249- An optional object allocator has been included. This allocator is
1250 optimized for Python objects and should be faster and use less memory
1251 than the standard system allocator. It is not enabled by default
1252 because of possible thread safety problems. The allocator is only
1253 protected by the Python interpreter lock and it is possible that some
1254 extension modules require a thread safe allocator. The object
1255 allocator can be enabled by providing the "--with-pymalloc" option to
1256 configure.
1257
Tim Petersd66595f2001-02-04 03:09:53 +00001258Standard library
1259
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001260- pyexpat now detects the expat version if expat.h defines it. A
1261 number of additional handlers are provided, which are only available
1262 since expat 1.95. In addition, the methods SetParamEntityParsing and
1263 GetInputContext of Parser objects are available with 1.95.x
1264 only. Parser objects now provide the ordered_attributes and
1265 specified_attributes attributes. A new module expat.model was added,
1266 which offers a number of additional constants if 1.95.x is used.
1267
1268- xml.dom offers the new functions registerDOMImplementation and
1269 getDOMImplementation.
1270
1271- xml.dom.minidom offers a toprettyxml method. A number of DOM
1272 conformance issues have been resolved. In particular, Element now
1273 has an hasAttributes method, and the handling of namespaces was
1274 improved.
1275
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001276- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1277 getting information about live Python code, and pydoc.py, a module
1278 for interactively converting docstrings to HTML or text.
1279 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001280 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001281 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1282 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001283
Tim Peters1eff7962001-03-01 02:31:33 +00001284- New library module difflib.py, primarily packaging the SequenceMatcher
1285 class at the heart of the popular ndiff.py file-comparison tool.
1286
1287- doctest.py (a framework for verifying Python code examples in docstrings)
1288 is now part of the std library.
1289
Tim Petersd66595f2001-02-04 03:09:53 +00001290Windows changes
1291
Guido van Rossume3955a82001-03-02 14:05:59 +00001292- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1293 small GUI that lets you browse the module docstrings using your
1294 default web browser.
1295
Tim Peters1eff7962001-03-01 02:31:33 +00001296- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1297 Platforms) is implemented. See
1298
1299 http://python.sourceforge.net/peps/pep-0235.html
1300
1301 for full details, especially the "Current Lower-Left Semantics" section.
1302 The new Windows import rules are simpler than before:
1303
1304 A. If the PYTHONCASEOK environment variable exists, same as
1305 before: silently accept the first case-insensitive match of any
1306 kind; raise ImportError if none found.
1307
1308 B. Else search sys.path for the first case-sensitive match; raise
1309 ImportError if none found.
1310
1311 The same rules have been implented on other platforms with case-
1312 insensitive but case-preserving filesystems too (including Cygwin, and
1313 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001314
Tim Peters25a9ce32001-02-19 07:06:36 +00001315- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1316 what it's supposed to do (and does do under NT and 2000) via direct
1317 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001318 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001319 all Win9x systems before.
1320
Tim Peters1eff7962001-03-01 02:31:33 +00001321- Build: Subproject _test (effectively) renamed to _testcapi.
1322
Tim Peters2fe289a2001-03-01 22:19:38 +00001323New platforms
1324
1325- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1326 Thanks to Steven Majewski!
1327
1328- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1329 Tishler!
1330
Guido van Rossum9089b272001-03-02 06:49:50 +00001331- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1332 Schwertberger! See RISCOS/README for more information -- it seems
1333 that because of the bizarre filename conventions on RISCOS, no port
1334 to that platform is easy. Note that the new variable os.endsep is
1335 silently supported in order to make life easier on this platform,
1336 but we don't advertise it because it's not worth for most folks to
1337 care about RISCOS portability.
1338
Tim Peters25a9ce32001-02-19 07:06:36 +00001339
Tim Petersd7b5e882001-01-25 03:36:26 +00001340What's New in Python 2.1 alpha 2?
1341=================================
Tim Peters40ead762001-01-27 05:35:26 +00001342
Tim Petersd7b5e882001-01-25 03:36:26 +00001343Core language, builtins, and interpreter
1344
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001345- Scopes nest. If a name is used in a function or class, but is not
1346 local, the definition in the nearest enclosing function scope will
1347 be used. One consequence of this change is that lambda statements
1348 could reference variables in the namespaces where the lambda is
1349 defined. In some unusual cases, this change will break code.
1350
1351 In all previous version of Python, names were resolved in exactly
1352 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001353 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001354 function A is defined within a function B, the names bound in B are
1355 not visible in A. The new rules make names bound in B visible in A,
1356 unless A contains a name binding that hides the binding in B.
1357
1358 Section 4.1 of the reference manual describes the new scoping rules
1359 in detail. The test script in Lib/test/test_scope.py demonstrates
1360 some of the effects of the change.
1361
1362 The new rules will cause existing code to break if it defines nested
1363 functions where an outer function has local variables with the same
1364 name as globals or builtins used by the inner function. Example:
1365
1366 def munge(str):
1367 def helper(x):
1368 return str(x)
1369 if type(str) != type(''):
1370 str = helper(str)
1371 return str.strip()
1372
1373 Under the old rules, the name str in helper() is bound to the
1374 builtin function str(). Under the new rules, it will be bound to
1375 the argument named str and an error will occur when helper() is
1376 called.
1377
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001378- The compiler will report a SyntaxError if "from ... import *" occurs
1379 in a function or class scope. The language reference has documented
1380 that this case is illegal, but the compiler never checked for it.
1381 The recent introduction of nested scope makes the meaning of this
1382 form of name binding ambiguous. In a future release, the compiler
1383 may allow this form when there is no possibility of ambiguity.
1384
Tim Peters40ead762001-01-27 05:35:26 +00001385- repr(string) is easier to read, now using hex escapes instead of octal,
1386 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1387
1388 >>> "\texample \r\n" + chr(0) + chr(255)
1389 '\texample \r\n\x00\xff' # in 2.1
1390 '\011example \015\012\000\377' # in 2.0
1391
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001392- Functions are now compared and hashed by identity, not by value, since
1393 the func_code attribute is writable.
1394
Fred Drakefb9d7122001-02-01 20:00:40 +00001395- Weak references (PEP 205) have been added. This involves a few
1396 changes in the core, an extension module (_weakref), and a Python
1397 module (weakref). The weakref module is the public interface. It
1398 includes support for "explicit" weak references, proxy objects, and
1399 mappings with weakly held values.
1400
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001401- A 'continue' statement can now appear in a try block within the body
1402 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001403 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001404
Tim Petersd7b5e882001-01-25 03:36:26 +00001405Standard library
1406
Barry Warsaw30dbd142001-01-31 22:14:01 +00001407- mailbox.py now has a new class, PortableUnixMailbox which is
1408 identical to UnixMailbox but uses a more portable scheme for
1409 determining From_ separators. Also, the constructors for all the
1410 classes in this module have a new optional `factory' argument, which
1411 is a callable used when new message classes must be instantiated by
1412 the next() method.
1413
Tim Petersd7b5e882001-01-25 03:36:26 +00001414- random.py is now self-contained, and offers all the functionality of
1415 the now-deprecated whrandom.py. See the docs for details. random.py
1416 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001417 and restoring the internal state of the generator; and jumpahead(n),
1418 for quickly forcing the internal state to be the same as if n calls to
1419 random() had been made. The latter is particularly useful for multi-
1420 threaded programs, creating one instance of the random.Random() class for
1421 each thread, then using .jumpahead() to force each instance to use a
1422 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001423
Tim Peters0de88fc2001-02-01 04:59:18 +00001424- random.py's seed() function is new. For bit-for-bit compatibility with
1425 prior releases, use the whseed function instead. The new seed function
1426 addresses two problems: (1) The old function couldn't produce more than
1427 about 2**24 distinct internal states; the new one about 2**45 (the best
1428 that can be done in the Wichmann-Hill generator). (2) The old function
1429 sometimes produced identical internal states when passed distinct
1430 integers, and there was no simple way to predict when that would happen;
1431 the new one guarantees to produce distinct internal states for all
1432 arguments in [0, 27814431486576L).
1433
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001434- The socket module now supports raw packets on Linux. The socket
1435 family is AF_PACKET.
1436
Tim Peters9ea17ac2001-02-02 05:57:15 +00001437- test_capi.py is a start at running tests of the Python C API. The tests
1438 are implemented by the new Modules/_testmodule.c.
1439
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001440- A new extension module, _symtable, provides provisional access to the
1441 internal symbol table used by the Python compiler. A higher-level
1442 interface will be added on top of _symtable in a future release.
1443
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001444- Removed the obsolete soundex module.
1445
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001446- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1447 the isSameNode method; NamedNodeMap the get method.
1448
1449- xml.sax.expatreader supports the lexical handler property; it
1450 generates comment, startCDATA, and endCDATA events.
1451
Tim Petersee826f82001-01-31 19:39:44 +00001452Windows changes
1453
1454- Build procedure: the zlib project is built in a different way that
1455 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001456 the zlib binary used. See PCbuild\readme.txt for details. Your old
1457 zlib-related directories can be deleted; you'll need to download fresh
1458 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001459
Tim Peters9ea17ac2001-02-02 05:57:15 +00001460- Build: New subproject _test for the benefit of test_capi.py (see above).
1461
Tim Petersb16c56f2001-02-02 21:24:51 +00001462- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1463 interface to some Python compiler internals).
1464
1465- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001466 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001467
Tim Petersa3a3a032000-11-30 05:22:44 +00001468What's New in Python 2.1 alpha 1?
1469=================================
1470
1471Core language, builtins, and interpreter
1472
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001473- There is a new Unicode companion to the PyObject_Str() API
1474 called PyObject_Unicode(). It behaves in the same way as the
1475 former, but assures that the returned value is an Unicode object
1476 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001477
Guido van Rossumf98eda02001-01-17 15:54:45 +00001478- The comparison operators support "rich comparison overloading" (PEP
1479 207). C extension types can provide a rich comparison function in
1480 the new tp_richcompare slot in the type object. The cmp() function
1481 and the C function PyObject_Compare() first try the new rich
1482 comparison operators before trying the old 3-way comparison. There
1483 is also a new C API PyObject_RichCompare() (which also falls back on
1484 the old 3-way comparison, but does not constrain the outcome of the
1485 rich comparison to a Boolean result).
1486
1487 The rich comparison function takes two objects (at least one of
1488 which is guaranteed to have the type that provided the function) and
1489 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1490 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1491 object, which may be NotImplemented (in which case the tp_compare
1492 slot function is used as a fallback, if defined).
1493
1494 Classes can overload individual comparison operators by defining one
1495 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001496 __ge__. There are no explicit "reflected argument" versions of
1497 these; instead, __lt__ and __gt__ are each other's reflection,
1498 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1499 reflection (similar at the C level). No other implications are
1500 made; in particular, Python does not assume that == is the Boolean
1501 inverse of !=, or that < is the Boolean inverse of >=. This makes
1502 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001503
1504 Classes or types that want to implement (in)equality tests but not
1505 the ordering operators (i.e. unordered types) should implement ==
1506 and !=, and raise an error for the ordering operators.
1507
Guido van Rossuma88479f2001-01-18 14:28:08 +00001508 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001509 Boolean; e.g. a matrix type might want to return a matrix of bits
1510 for A < B, giving elementwise comparisons. Such types should ensure
1511 that any interpretation of their value in a Boolean context raises
1512 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1513 at the C level) to always raise an exception.
1514
Guido van Rossuma88479f2001-01-18 14:28:08 +00001515- Complex numbers use rich comparisons to define == and != but raise
1516 an exception for <, <=, > and >=. Unfortunately, this also means
1517 that cmp() of two complex numbers raises an exception when the two
1518 numbers differ. Since it is not mathematically meaningful to compare
1519 complex numbers except for equality, I hope that this doesn't break
1520 too much code.
1521
Tim Peters3389f192001-02-18 08:48:49 +00001522- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001523 not defined by the language, other than that it's arbitrary but
1524 consistent (see the Reference Manual). An implementation detail changed
1525 in 2.1a1 such that None now compares less than any other object. Code
1526 relying on this new behavior (like code that relied on the previous
1527 behavior) does so at its own risk.
1528
Barry Warsaw573b5412001-01-15 20:43:18 +00001529- Functions and methods now support getting and setting arbitrarily
1530 named attributes (PEP 232). Functions have a new __dict__
1531 (a.k.a. func_dict) which hold the function attributes. Methods get
1532 and set attributes on their underlying im_func. It is a TypeError
1533 to set an attribute on a bound method.
1534
Guido van Rossum051e3352001-01-15 19:11:10 +00001535- The xrange() object implementation has been improved so that
1536 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1537 limitation that in this case len(xrange(sys.maxint)) can't be
1538 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1539 work fine as long as the index i doesn't actually reach 2**31.
1540 (Python uses regular ints for sequence and string indices; fixing
1541 that is much more work.)
1542
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001543- Two changes to from...import:
1544
Guido van Rossumba381232001-02-03 15:06:40 +00001545 1) "from M import X" now works even if (after loading module M)
1546 sys.modules['M'] is not a real module; it's basically a getattr()
1547 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001548
1549 2) "from M import *" now looks for M.__all__ to decide which names to
1550 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1551 filters out names starting with '_' as before. Whether or not
1552 __all__ exists, there's no restriction on the type of M.
1553
Guido van Rossumf61f1662001-01-10 20:13:55 +00001554- File objects have a new method, xreadlines(). This is the fastest
1555 way to iterate over all lines in a file:
1556
1557 for line in file.xreadlines():
1558 ...do something to line...
1559
1560 See the xreadlines module (mentioned below) for how to do this for
1561 other file-like objects.
1562
1563- Even if you don't use file.xreadlines(), you may expect a speedup on
1564 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001565 quite a bit in platform-specific ways: on systems (like Linux) that
1566 support flockfile(), getc_unlocked(), and funlockfile(), those are
1567 used by default. On systems (like Windows) without getc_unlocked(),
1568 a complicated (but still thread-safe) method using fgets() is used by
1569 default.
1570
Tim Petersd52269b2001-01-25 06:23:18 +00001571 You can force use of the fgets() method by #define'ing
1572 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001573 getc_unlocked()).
1574
Tim Petersd52269b2001-01-25 06:23:18 +00001575 You can force fgets() not to be used by #define'ing
1576 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001577 test_bufio.py fails -- and let us know if it does!).
1578
1579- In addition, the fileinput module, while still slower than the other
1580 methods on most platforms, has been sped up too, by using
1581 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001582
1583- Support for run-time warnings has been added, including a new
1584 command line option (-W) to specify the disposition of warnings.
1585 See the description of the warnings module below.
1586
1587- Extensive changes have been made to the coercion code. This mostly
1588 affects extension modules (which can now implement mixed-type
1589 numerical operators without having to use coercion), but
1590 occasionally, in boundary cases the coercion semantics have changed
1591 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001592 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001593 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001594 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001595
Guido van Rossumf98eda02001-01-17 15:54:45 +00001596- In connection with the coercion changes, a new built-in singleton
1597 object, NotImplemented is defined. This can be returned for
1598 operations that wish to indicate they are not implemented for a
1599 particular combination of arguments. From C, this is
1600 Py_NotImplemented.
1601
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001602- The interpreter accepts now bytecode files on the command line even
1603 if they do not have a .pyc or .pyo extension. On Linux, after executing
1604
Martin v. Löwise214baa2001-02-04 22:37:56 +00001605import imp,sys,string
1606magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1607reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1608open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001609
1610 any byte code file can be used as an executable (i.e. as an argument
1611 to execve(2)).
1612
Tim Peters9940b802000-12-01 07:59:35 +00001613- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001614 character. In 1.6 and earlier, they never produced a sign,
1615 and raised an error if the value of the long was too large
1616 to fit in a Python int. In 2.0, they produced a sign if and
1617 only if too large to fit in an int. This was inconsistent
1618 across platforms (because the size of an int varies across
1619 platforms), and inconsistent with hex() and oct(). Example:
1620
1621 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001622 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001623 'ffffffbe' # in 2.0 and before, on 32-bit machines
1624 >>> hex(-0x42L)
1625 '-0x42L' # in all versions of Python
1626
Tim Peters9940b802000-12-01 07:59:35 +00001627 The behavior of %d formats for negative Python longs remains
1628 the same as in 2.0 (although in 1.6 and before, they raised
1629 an error if the long didn't fit in a Python int).
1630
1631 %u formats don't make sense for Python longs, but are allowed
1632 and treated the same as %d in 2.1. In 2.0, a negative long
1633 formatted via %u produced a sign if and only if too large to
1634 fit in an int. In 1.6 and earlier, a negative long formatted
1635 via %u raised an error if it was too big to fit in an int.
1636
Guido van Rossum3661d392000-12-12 22:10:31 +00001637- Dictionary objects have an odd new method, popitem(). This removes
1638 an arbitrary item from the dictionary and returns it (in the form of
1639 a (key, value) pair). This can be useful for algorithms that use a
1640 dictionary as a bag of "to do" items and repeatedly need to pick one
1641 item. Such algorithms normally end up running in quadratic time;
1642 using popitem() they can usually be made to run in linear time.
1643
Tim Peters36cdad12000-12-29 02:06:45 +00001644Standard library
1645
Thomas Woutersfe385252001-01-19 23:16:56 +00001646- In the time module, the time argument to the functions strftime,
1647 localtime, gmtime, asctime and ctime is now optional, defaulting to
1648 the current time (in the local timezone).
1649
Guido van Rossumda91f222001-01-15 16:36:08 +00001650- The ftplib module now defaults to passive mode, which is deemed a
1651 more useful default given that clients are often inside firewalls
1652 these days. Note that this could break if ftplib is used to connect
1653 to a *server* that is inside a firewall, from outside; this is
1654 expected to be a very rare situation. To fix that, you can call
1655 ftp.set_pasv(0).
1656
Martin v. Löwis10a27872001-01-13 09:54:41 +00001657- The module site now treats .pth files not only for path configuration,
1658 but also supports extensions to the initialization code: Lines starting
1659 with import are executed.
1660
Guido van Rossumf61f1662001-01-10 20:13:55 +00001661- There's a new module, warnings, which implements a mechanism for
1662 issuing and filtering warnings. There are some new built-in
1663 exceptions that serve as warning categories, and a new command line
1664 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1665 turns warnings into errors). warnings.warn(message[, category])
1666 issues a warning message; this can also be called from C as
1667 PyErr_Warn(category, message).
1668
1669- A new module xreadlines was added. This exports a single factory
1670 function, xreadlines(). The intention is that this code is the
1671 absolutely fastest way to iterate over all lines in an open
1672 file(-like) object:
1673
1674 import xreadlines
1675 for line in xreadlines.xreadlines(file):
1676 ...do something to line...
1677
1678 This is equivalent to the previous the speed record holder using
1679 file.readlines(sizehint). Note that if file is a real file object
1680 (as opposed to a file-like object), this is equivalent:
1681
1682 for line in file.xreadlines():
1683 ...do something to line...
1684
Tim Peters36cdad12000-12-29 02:06:45 +00001685- The bisect module has new functions bisect_left, insort_left,
1686 bisect_right and insort_right. The old names bisect and insort
1687 are now aliases for bisect_right and insort_right. XXX_right
1688 and XXX_left methods differ in what happens when the new element
1689 compares equal to one or more elements already in the list: the
1690 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001691 right. Code that doesn't care where equal elements end up should
1692 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001693
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001694- The new curses.panel module wraps the panel library that forms part
1695 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1696
Guido van Rossumf61f1662001-01-10 20:13:55 +00001697- The SocketServer module now sets the allow_reuse_address flag by
1698 default in the TCPServer class.
1699
1700- A new function, sys._getframe(), returns the stack frame pointer of
1701 the caller. This is intended only as a building block for
1702 higher-level mechanisms such as string interpolation.
1703
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001704- The pyexpat module supports a number of new handlers, which are
1705 available only in expat 1.2. If invocation of a callback fails, it
1706 will report an additional frame in the traceback. Parser objects
1707 participate now in garbage collection. If expat reports an unknown
1708 encoding, pyexpat will try to use a Python codec; that works only
1709 for single-byte charsets. The parser type objects is exposed as
1710 XMLParserObject.
1711
1712- xml.dom now offers standard definitions for symbolic node type and
1713 exception code constants, and a hierarchy of DOM exceptions. minidom
1714 was adjusted to use them.
1715
1716- The conformance of xml.dom.minidom to the DOM specification was
1717 improved. It detects a number of additional error cases; the
1718 previous/next relationship works even when the tree is modified;
1719 Node supports the normalize() method; NamedNodeMap, DocumentType and
1720 DOMImplementation classes were added; Element supports the
1721 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1722 method.
1723
Guido van Rossumf61f1662001-01-10 20:13:55 +00001724Build issues
1725
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001726- For Unix (and Unix-compatible) builds, configuration and building of
1727 extension modules is now greatly automated. Rather than having to
1728 edit the Modules/Setup file to indicate which modules should be
1729 built and where their include files and libraries are, a
1730 distutils-based setup.py script now takes care of building most
1731 extension modules. All extension modules built this way are built
1732 as shared libraries. Only a few modules that must be linked
1733 statically are still listed in the Setup file; you won't need to
1734 edit their configuration.
1735
1736- Python should now build out of the box on Cygwin. If it doesn't,
1737 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001738
1739- Python now always uses its own (renamed) implementation of getopt()
1740 -- there's too much variation among C library getopt()
1741 implementations.
1742
1743- C++ compilers are better supported; the CXX macro is always set to a
1744 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001745
Tim Petersd92dfe02000-12-12 01:18:41 +00001746Windows changes
1747
1748- select module: By default under Windows, a select() call
1749 can specify no more than 64 sockets. Python now boosts
1750 this Microsoft default to 512. If you need even more than
1751 that, see the MS docs (you'll need to #define FD_SETSIZE
1752 and recompile Python from source).
1753
Guido van Rossumf61f1662001-01-10 20:13:55 +00001754- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1755 subdirectory is no more!
1756
Tim Petersa3a3a032000-11-30 05:22:44 +00001757
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001758What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001759=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001760
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001761Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001762changes are in the file HISTORY. If you are making the jump directly
1763from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1764HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001765
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001766Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1767the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1768http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001769
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001770--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001771
1772======================================================================
1773
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001774What's new in 2.0 (since release candidate 1)?
1775==============================================
1776
1777Standard library
1778
1779- The copy_reg module was modified to clarify its intended use: to
1780 register pickle support for extension types, not for classes.
1781 pickle() will raise a TypeError if it is passed a class.
1782
1783- Fixed a bug in gettext's "normalize and expand" code that prevented
1784 it from finding an existing .mo file.
1785
1786- Restored support for HTTP/0.9 servers in httplib.
1787
Tim Peters989b7b92000-10-16 20:24:53 +00001788- The math module was changed to stop raising OverflowError in case of
1789 underflow, and return 0 instead in underflow cases. Whether Python
1790 used to raise OverflowError in case of underflow was platform-
1791 dependent (it did when the platform math library set errno to ERANGE
1792 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001793
1794- Fixed a bug in StringIO that occurred when the file position was not
1795 at the end of the file and write() was called with enough data to
1796 extend past the end of the file.
1797
1798- Fixed a bug that caused Tkinter error messages to get lost on
1799 Windows. The bug was fixed by replacing direct use of
1800 interp->result with Tcl_GetStringResult(interp).
1801
1802- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1803 redirect response.
1804
1805- Several changes were made to distutils: Some debugging code was
1806 removed from util. Fixed the installer used when an external zip
1807 program (like WinZip) is not found; the source code for this
1808 installer is in Misc/distutils. check_lib() was modified to behave
1809 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1810 test for whether installed modules are on sys.path was changed to
1811 use both normcase() and normpath().
1812
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001813- Several minor bugs were fixed in the xml package (the minidom,
1814 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001815
1816- The regression test driver (regrtest.py) behavior when invoked with
1817 -l changed: It now reports a count of objects that are recognized as
1818 garbage but not freed by the garbage collector.
1819
Tim Peters989b7b92000-10-16 20:24:53 +00001820- The regression test for the math module was changed to test
1821 exceptional behavior when the test is run in verbose mode. Python
1822 cannot yet guarantee consistent exception behavior across platforms,
1823 so the exception part of test_math is run only in verbose mode, and
1824 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001825
1826Internals
1827
1828- PyOS_CheckStack() has been disabled on Win64, where it caused
1829 test_sre to fail.
1830
1831Build issues
1832
1833- Changed compiler flags, so that gcc is always invoked with -Wall and
1834 -Wstrict-prototypes. Users compiling Python with GCC should see
1835 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001836 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001837 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001838
Tim Petersa3a3a032000-11-30 05:22:44 +00001839- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001840
1841Tools and other miscellany
1842
1843- The compiler in Tools/compiler was updated to support the new
1844 language features introduced in 2.0: extended print statement, list
1845 comprehensions, and augmented assignments. The new compiler should
1846 also be backwards compatible with Python 1.5.2; the compiler will
1847 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001848 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001849
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001850What's new in 2.0 release candidate 1 (since beta 2)?
1851=====================================================
1852
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001853What is release candidate 1?
1854
1855We believe that release candidate 1 will fix all known bugs that we
1856intend to fix for the 2.0 final release. This release should be a bit
1857more stable than the previous betas. We would like to see even more
1858widespread testing before the final release, so we are producing this
1859release candidate. The final release will be exactly the same unless
1860any show-stopping (or brown bag) bugs are found by testers of the
1861release candidate.
1862
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001863All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001864to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001865
1866Core language, builtins, and interpreter
1867
1868- A bug that caused crashes when __coerce__ was used with augmented
1869 assignment, e.g. +=, was fixed.
1870
1871- Raise ZeroDivisionError when raising zero to a negative number,
1872 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1873 power operator and the result of math.pow(0.0, -2.0) will vary by
1874 platform. On Linux, it raises a ValueError.
1875
1876- A bug in Unicode string interpolation was fixed that occasionally
1877 caused errors with formats including "%%". For example, the
1878 following expression "%% %s" % u"abc" no longer raises a TypeError.
1879
1880- Compilation of deeply nested expressions raises MemoryError instead
1881 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1882
1883- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1884 rendering them useless. They are now written in binary mode again.
1885
1886Standard library
1887
1888- Keyword arguments are now accepted for most pattern and match object
1889 methods in SRE, the standard regular expression engine.
1890
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001891- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001892 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001893
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001894- Several bugs in the Unicode handling and error handling in _tkinter
1895 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001896
1897- Fix memory management errors in Merge() and Tkapp_Call() routines.
1898
1899- Several changes were made to cStringIO to make it compatible with
1900 the file-like object interface and with StringIO. If operations are
1901 performed on a closed object, an exception is raised. The truncate
1902 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001903 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001904
1905- There were many changes made to the linuxaudiodev module and its
1906 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001907 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001908
1909 Note that this module is named poorly, because it should work
1910 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001911 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001912
1913 The module now raises exceptions when errors occur instead of
1914 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1915 audio) and defines a getptr() method that calls the
1916 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1917
1918- The library_version attribute, introduced in an earlier beta, was
1919 removed because it can not be supported with early versions of the C
1920 readline library, which provides no way to determine the version at
1921 compile-time.
1922
1923- The binascii module is now enabled on Win64.
1924
Tim Peters46446d62000-10-09 21:19:31 +00001925- tokenize.py no longer suffers "recursion depth" errors when parsing
1926 programs with very long string literals.
1927
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001928Internals
1929
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001930- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001931 which is called when the interpreter starts up to determine where
1932 the standard library is installed. These vulnerabilities affect all
1933 previous versions of Python and can be exploited by setting very
1934 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1935 setuid Python script, although use of the wrapper in
1936 Misc/setuid-prog.c will eliminate the vulnerability.
1937
1938- Fixed garbage collection bugs in instance creation that were
1939 triggered when errors occurred during initialization. The solution,
1940 applied in cPickle and in PyInstance_New(), is to call
1941 PyObject_GC_Init() after the initialization of the object's
1942 container attributes is complete.
1943
1944- pyexpat adds definitions of PyModule_AddStringConstant and
1945 PyModule_AddObject if the Python version is less than 2.0, which
1946 provides compatibility with PyXML on Python 1.5.2.
1947
1948- If the platform has a bogus definition for LONG_BIT (the number of
1949 bits in a long), an error will be reported at compile time.
1950
1951- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1952 collection crashes and possibly other, unreported crashes.
1953
1954- Fixed a memory leak in _PyUnicode_Fini().
1955
1956Build issues
1957
1958- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001959 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001960 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001961
1962- The mmap.PAGESIZE constant is now initialized using sysconf when
1963 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1964
1965- The md5 file should now compile on all platforms.
1966
1967- The select module now compiles on platforms that do not define
1968 POLLRDNORM and related constants.
1969
1970- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001971 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001972
Jeremy Hylton10921202000-10-09 18:34:12 +00001973- BeOS: A number of changes were made to the build and installation
1974 process. ar-fake now operates on a directory of object files.
1975 dl_export.h is gone, and its macros now appear on the mwcc command
1976 line during build on PPC BeOS.
1977
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001978- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001979 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001980
1981- Cygwin: Support for shared libraries, Tkinter, and sockets.
1982
1983- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1984
1985Tools and other miscellany
1986
1987- Removed debugging prints from main used with freeze.
1988
Tim Peters46446d62000-10-09 21:19:31 +00001989- IDLE auto-indent no longer crashes when it encounters Unicode
1990 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001991
1992What's new in 2.0 beta 2 (since beta 1)?
1993========================================
1994
1995Core language, builtins, and interpreter
1996
Tim Peters482c0212000-09-26 06:33:09 +00001997- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001998 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001999
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002000- Add -h and -V command line options to print the usage message and
2001 Python version number and exit immediately.
2002
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002003- eval() and exec accept Unicode objects as code parameters.
2004
2005- getattr() and setattr() now also accept Unicode objects for the
2006 attribute name, which are converted to strings using the default
2007 encoding before lookup.
2008
2009- Multiplication on string and Unicode now does proper bounds
2010 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
2011 string is too long."
2012
2013- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00002014 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002015
Jeremy Hylton1b618592000-09-26 05:32:36 +00002016
2017Standard library and extensions
2018
Guido van Rossum5b08f132001-04-16 02:05:23 +00002019- socket module: the OpenSSL code now adds support for RAND_status()
2020 and EGD (Entropy Gathering Device).
2021
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002022- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002023 argument checking; it still takes no arguments.
2024
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002025- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002026
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002027- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002028
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002029- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002030
2031- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002032 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002033
2034- copy: Copy Unicode objects atomically.
2035
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002036- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002037
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002038- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002039
Fred Drake67233bc2000-09-26 16:40:27 +00002040- dbm: Add get() and setdefault() methods to dbm object. Add constant
2041 `library' to module that names the library used. Added doc strings
2042 and method names to error messages. Uses configure to determine
2043 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2044 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002045
2046- distutils: Update to version 0.9.3.
2047
2048- dl: Add several dl.RTLD_ constants.
2049
2050- fpectl: Now supported on FreeBSD.
2051
2052- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2053 found by the collector will be saved in gc.garbage. This is useful
2054 for debugging a program that creates reference cycles.
2055
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002056- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002057 of HTTP class. Do not close socket on zero-length response. Do not
2058 crash when server sends invalid content-length header.
2059
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002060- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002061
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002062- marshal: When reading a short, sign-extend on platforms where shorts
2063 are bigger than 16 bits. When reading a long, repair the unportable
2064 sign extension that was being done for 64-bit machines. (It assumed
2065 that signed right shift sign-extends.)
2066
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002067- operator: Add contains(), invert(), __invert__() as aliases for
2068 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002069
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002070- os: Add support for popen2() and popen3() on all platforms where
2071 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002072
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002073- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002074 clicking on a file in Explorer (or passing the file name to the
2075 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002076
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002077- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002078 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002079
2080- pickle: Now raises ValueError when an invalid pickle that contains
2081 a non-string repr where a string repr was expected. This behavior
2082 matches cPickle.
2083
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002084- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002085
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002086- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002087
2088- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002089 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002090 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002091
2092- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002093 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002094
2095- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002096 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002097 few cycles during startup since the first call to
2098 setdefaultencoding() will initialize the codec registry and the
2099 encodings package.
2100
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002101- socket: Support for size hint in readlines() method of object returned
2102 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002103
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002104- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002105 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002106 is followed by whitespace.
2107
Tim Petersa3a3a032000-11-30 05:22:44 +00002108- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002109
2110- struct: Check ranges for bytes and shorts.
2111
2112- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002113 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002114
2115- Tkinter: Image objects are now guaranteed to have unique ids. Set
2116 event.delta to zero if Tk version doesn't support mousewheel.
2117 Removed some debugging prints.
2118
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002119- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002120
Fred Drake67233bc2000-09-26 16:40:27 +00002121- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002122 which works around a bug in Norton AntiVirus 2000 that leads directly
2123 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002124
2125- xml: New version detection code allows PyXML to override standard
2126 XML package if PyXML version is greater than 0.6.1.
2127
Fred Drake64bb3802000-09-26 16:21:35 +00002128- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2129 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2130 tree only for nodes which are sufficiently interesting to a specific
2131 application. Does not provide the HTML-specific extensions. Still
2132 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002133
Fred Drake64bb3802000-09-26 16:21:35 +00002134- xml.sax: SAX 2 support for Python, including all the handler
2135 interfaces needed to process XML 1.0 compliant XML. Some
2136 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002137
Fred Drake64bb3802000-09-26 16:21:35 +00002138- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2139 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002140
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002141
Jeremy Hylton1b618592000-09-26 05:32:36 +00002142C API
2143
2144- Add three new convenience functions for module initialization --
2145 PyModule_AddObject(), PyModule_AddIntConstant(), and
2146 PyModule_AddStringConstant().
2147
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002148- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002149 removed and add #error to Python.h if NULL isn't defined after
2150 #include of stdio.h.
2151
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002152- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002153 backwards compatibility (at the source level) with old extensions.
2154
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002155- A wrapper API was added for signal() and sigaction(). Instead of
2156 either function, always use PyOS_getsig() to get a signal handler
2157 and PyOS_setsig() to set one. A new convenience typedef
2158 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002159
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002160- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002161 internal data buffer and size of a string object -- or the default
2162 encoded version of a Unicode object.
2163
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002164- PyString_Size() and PyString_AsString() accept Unicode objects.
2165
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002166- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002167 exists). INT_MAX and LONG_MAX will always be defined, even if
2168 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002169
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002170- PyFloat_FromString takes a second argument, pend, that was
2171 effectively useless. It is now officially useless but preserved for
2172 backwards compatibility. If the pend argument is not NULL, *pend is
2173 set to NULL.
2174
2175- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2176 for the attribute name. See note on getattr() above.
2177
2178- A few bug fixes to argument processing for Unicode.
2179 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2180 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2181 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002182 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002183
2184- Py_BuildValue accepts B format (for bgen-generated code).
2185
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002186
Jeremy Hylton1b618592000-09-26 05:32:36 +00002187Internals
2188
2189- On Unix, fix code for finding Python installation directory so that
2190 it works when argv[0] is a relative path.
2191
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002192- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002193 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002194 rather than by generating a copy of the object.
2195
Tim Peters482c0212000-09-26 06:33:09 +00002196- Several of the internal Unicode tables are much smaller now, and
2197 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002198
Jeremy Hylton97693b02000-09-26 17:42:51 +00002199- In the garbage collector: Fixed bug in collection of tuples. Fixed
2200 bug that caused some instances to be removed from the container set
2201 while they were still live. Fixed parsing in gc.set_debug() for
2202 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002203
2204- Fixed refcount problem in instance deallocation that only occurred
2205 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2206
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002207- On Windows, getpythonregpath is now protected against null data in
2208 registry key.
2209
2210- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002211 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002212
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002213
Jeremy Hylton1b618592000-09-26 05:32:36 +00002214Build and platform-specific issues
2215
2216- Better support of GNU Pth via --with-pth configure option.
2217
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002218- Python/C API now properly exposed to dynamically-loaded extension
2219 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002220
2221- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2222 Don't define MS_SYNC to be zero when it is undefined. Added missing
2223 prototypes in posixmodule.c.
2224
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002225- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002226 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002227
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002228- Fix largefile support on older NetBSD systems and OpenBSD by adding
2229 define for TELL64.
2230
2231
2232Tools and other miscellany
2233
2234- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2235
2236- freeze: The modulefinder now works with 2.0 opcodes.
2237
Tim Petersa3a3a032000-11-30 05:22:44 +00002238- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002239 Move hackery of sys.argv until after the Tk instance has been
2240 created, which allows the application-specific Tkinter
2241 initialization to be executed if present; also pass an explicit
2242 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002243
Jeremy Hylton1b618592000-09-26 05:32:36 +00002244
2245What's new in 2.0 beta 1?
2246=========================
2247
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002248Source Incompatibilities
2249------------------------
2250
2251None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2252such as single-argument append(), connect() and bind(), and changes to
2253str(long) and repr(float).
2254
2255
2256Binary Incompatibilities
2257------------------------
2258
2259- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2260with Python 2.0; these extensions will have to be rebuilt for Python
22612.0.
2262
2263- On Windows, attempting to import a third party extension built for
2264Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2265can do about this. Check your PYTHONPATH environment variable!
2266
2267- Python bytecode files (*.pyc and *.pyo) are not compatible between
2268releases.
2269
2270
2271Overview of Changes Since 1.6
2272-----------------------------
2273
2274There are many new modules (including brand new XML support through
2275the xml package, and i18n support through the gettext module); a list
2276of all new modules is included below. Lots of bugs have been fixed.
2277
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002278The process for making major new changes to the language has changed
2279since Python 1.6. Enhancements must now be documented by a Python
2280Enhancement Proposal (PEP) before they can be accepted.
2281
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002282There are several important syntax enhancements, described in more
2283detail below:
2284
2285 - Augmented assignment, e.g. x += 1
2286
2287 - List comprehensions, e.g. [x**2 for x in range(10)]
2288
2289 - Extended import statement, e.g. import Module as Name
2290
2291 - Extended print statement, e.g. print >> file, "Hello"
2292
2293Other important changes:
2294
2295 - Optional collection of cyclical garbage
2296
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002297Python Enhancement Proposal (PEP)
2298---------------------------------
2299
2300PEP stands for Python Enhancement Proposal. A PEP is a design
2301document providing information to the Python community, or describing
2302a new feature for Python. The PEP should provide a concise technical
2303specification of the feature and a rationale for the feature.
2304
2305We intend PEPs to be the primary mechanisms for proposing new
2306features, for collecting community input on an issue, and for
2307documenting the design decisions that have gone into Python. The PEP
2308author is responsible for building consensus within the community and
2309documenting dissenting opinions.
2310
2311The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002312
2313Augmented Assignment
2314--------------------
2315
2316This must have been the most-requested feature of the past years!
2317Eleven new assignment operators were added:
2318
Guido van Rossume905e952000-09-05 12:42:46 +00002319 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002320
2321For example,
2322
2323 A += B
2324
2325is similar to
2326
2327 A = A + B
2328
2329except that A is evaluated only once (relevant when A is something
2330like dict[index].attr).
2331
2332However, if A is a mutable object, A may be modified in place. Thus,
2333if A is a number or a string, A += B has the same effect as A = A+B
2334(except A is only evaluated once); but if a is a list, A += B has the
2335same effect as A.extend(B)!
2336
2337Classes and built-in object types can override the new operators in
2338order to implement the in-place behavior; the not-in-place behavior is
2339used automatically as a fallback when an object doesn't implement the
2340in-place behavior. For classes, the method name is derived from the
2341method name for the corresponding not-in-place operator by inserting
2342an 'i' in front of the name, e.g. __iadd__ implements in-place
2343__add__.
2344
2345Augmented assignment was implemented by Thomas Wouters.
2346
2347
2348List Comprehensions
2349-------------------
2350
2351This is a flexible new notation for lists whose elements are computed
2352from another list (or lists). The simplest form is:
2353
2354 [<expression> for <variable> in <sequence>]
2355
Guido van Rossum56db0952000-09-06 23:34:25 +00002356For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002357This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002358
2359You can also add a condition:
2360
2361 [<expression> for <variable> in <sequence> if <condition>]
2362
2363For example, [w for w in words if w == w.lower()] would yield the list
2364of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002365than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002366
2367You can also have nested for loops and more than one 'if' clause. For
2368example, here's a function that flattens a sequence of sequences::
2369
2370 def flatten(seq):
2371 return [x for subseq in seq for x in subseq]
2372
2373 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2374
2375This prints
2376
2377 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2378
2379List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002380Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002381
2382
2383Extended Import Statement
2384-------------------------
2385
2386Many people have asked for a way to import a module under a different
2387name. This can be accomplished like this:
2388
2389 import foo
2390 bar = foo
2391 del foo
2392
2393but this common idiom gets old quickly. A simple extension of the
2394import statement now allows this to be written as follows:
2395
2396 import foo as bar
2397
2398There's also a variant for 'from ... import':
2399
2400 from foo import bar as spam
2401
2402This also works with packages; e.g. you can write this:
2403
2404 import test.regrtest as regrtest
2405
2406Note that 'as' is not a new keyword -- it is recognized only in this
2407context (this is only possible because the syntax for the import
2408statement doesn't involve expressions).
2409
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002410Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002411
2412
2413Extended Print Statement
2414------------------------
2415
2416Easily the most controversial new feature, this extension to the print
2417statement adds an option to make the output go to a different file
2418than the default sys.stdout.
2419
2420For example, to write an error message to sys.stderr, you can now
2421write:
2422
2423 print >> sys.stderr, "Error: bad dog!"
2424
2425As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002426evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002427
2428 print >> None, "Hello world"
2429
2430is equivalent to
2431
2432 print "Hello world"
2433
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002434Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002435
2436
2437Optional Collection of Cyclical Garbage
2438---------------------------------------
2439
2440Python is now equipped with a garbage collector that can hunt down
2441cyclical references between Python objects. It's no replacement for
2442reference counting; in fact, it depends on the reference counts being
2443correct, and decides that a set of objects belong to a cycle if all
2444their reference counts can be accounted for from their references to
2445each other. This devious scheme was first proposed by Eric Tiedemann,
2446and brought to implementation by Neil Schemenauer.
2447
2448There's a module "gc" that lets you control some parameters of the
2449garbage collection. There's also an option to the configure script
2450that lets you enable or disable the garbage collection. In 2.0b1,
2451it's on by default, so that we (hopefully) can collect decent user
2452experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002453performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002454off by default in the final 2.0 release.
2455
2456
2457Smaller Changes
2458---------------
2459
2460A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2461map(None, seq1, seq2, ...) when the sequences have the same length;
2462i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2463the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002464zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002465
2466sys.version_info is a tuple (major, minor, micro, level, serial).
2467
2468Dictionaries have an odd new method, setdefault(key, default).
2469dict.setdefault(key, default) returns dict[key] if it exists; if not,
2470it sets dict[key] to default and returns that value. Thus:
2471
2472 dict.setdefault(key, []).append(item)
2473
2474does the same work as this common idiom:
2475
2476 if not dict.has_key(key):
2477 dict[key] = []
2478 dict[key].append(item)
2479
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002480There are two new variants of SyntaxError that are raised for
2481indentation-related errors: IndentationError and TabError.
2482
2483Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2484escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002485
2486The limits on the size of expressions and file in Python source code
2487have been raised from 2**16 to 2**32. Previous versions of Python
2488were limited because the maximum argument size the Python VM accepted
2489was 2**16. This limited the size of object constructor expressions,
2490e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2491limit was raised thanks to a patch by Charles Waldman that effectively
2492fixes the problem. It is now much more likely that you will be
2493limited by available memory than by an arbitrary limit in Python.
2494
2495The interpreter's maximum recursion depth can be modified by Python
2496programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2497limit is the maximum number of recursive calls that can be made by
2498Python code. The limit exists to prevent infinite recursion from
2499overflowing the C stack and causing a core dump. The default value is
25001000. The maximum safe value for a particular platform can be found
2501by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002502
2503New Modules and Packages
2504------------------------
2505
2506atexit - for registering functions to be called when Python exits.
2507
2508imputil - Greg Stein's alternative API for writing custom import
2509hooks.
2510
2511pyexpat - an interface to the Expat XML parser, contributed by Paul
2512Prescod.
2513
2514xml - a new package with XML support code organized (so far) in three
2515subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2516would fill a volume. There's a special feature whereby a
2517user-installed package named _xmlplus overrides the standard
2518xmlpackage; this is intended to give the XML SIG a hook to distribute
2519backwards-compatible updates to the standard xml package.
2520
2521webbrowser - a platform-independent API to launch a web browser.
2522
2523
Guido van Rossume905e952000-09-05 12:42:46 +00002524Changed Modules
2525---------------
2526
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002527array -- new methods for array objects: count, extend, index, pop, and
2528remove
2529
2530binascii -- new functions b2a_hex and a2b_hex that convert between
2531binary data and its hex representation
2532
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002533calendar -- Many new functions that support features including control
2534over which day of the week is the first day, returning strings instead
2535of printing them. Also new symbolic constants for days of week,
2536e.g. MONDAY, ..., SUNDAY.
2537
2538cgi -- FieldStorage objects have a getvalue method that works like a
2539dictionary's get method and returns the value attribute of the object.
2540
2541ConfigParser -- The parser object has new methods has_option,
2542remove_section, remove_option, set, and write. They allow the module
2543to be used for writing config files as well as reading them.
2544
2545ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002546optionally support the RFC 959 REST command.
2547
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002548gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002549
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002550httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2551the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002552
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002553locale -- implement getdefaultlocale for Win32 and Macintosh
2554
2555marshal -- no longer dumps core when marshaling deeply nested or
2556recursive data structures
2557
2558os -- new functions isatty, seteuid, setegid, setreuid, setregid
2559
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002560os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2561support under Unix.
2562
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002563os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002564
2565os.path -- fix semantics of os.path.commonprefix
2566
2567smtplib -- support for sending very long messages
2568
2569socket -- new function getfqdn()
2570
2571readline -- new functions to read, write and truncate history files.
2572The readline section of the library reference manual contains an
2573example.
2574
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002575select -- add interface to poll system call
2576
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002577shutil -- new copyfileobj function
2578
2579SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2580HTTP server.
2581
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002582Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002583
2584urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002585e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002586
2587whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002588
2589
2590Obsolete Modules
2591----------------
2592
2593None. However note that 1.6 made a whole slew of modules obsolete:
2594stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2595poly, zmod, strop, util, whatsound.
2596
2597
2598Changed, New, Obsolete Tools
2599----------------------------
2600
Tim Peters8b092332000-09-05 20:15:25 +00002601None.
Guido van Rossume905e952000-09-05 12:42:46 +00002602
2603
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002604C-level Changes
2605---------------
2606
2607Several cleanup jobs were carried out throughout the source code.
2608
2609All C code was converted to ANSI C; we got rid of all uses of the
2610Py_PROTO() macro, which makes the header files a lot more readable.
2611
2612Most of the portability hacks were moved to a new header file,
2613pyport.h; several other new header files were added and some old
2614header files were removed, in an attempt to create a more rational set
2615of header files. (Few of these ever need to be included explicitly;
2616they are all included by Python.h.)
2617
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002618Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002619and Win64, especially for the new Intel Itanium processor. Mick also
2620added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002621
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002622The C APIs to return an object's size have been update to consistently
2623use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2624previous versions, the abstract interfaces used PyXXX_Length and the
2625concrete interfaces used PyXXX_Size. The old names,
2626e.g. PyObject_Length, are still available for backwards compatibility
2627at the API level, but are deprecated.
2628
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002629The PyOS_CheckStack function has been implemented on Windows by
2630Fredrik Lundh. It prevents Python from failing with a stack overflow
2631on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002632
2633The GC changes resulted in creation of two new slots on object,
2634tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002635the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002636
2637The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002638C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002639
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002640PyErr_Format has been updated to automatically calculate the size of
2641the buffer needed to hold the formatted result string. This change
2642prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002643
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002644New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002645
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002646PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2647that are the same as their non-Ex counterparts except they take an
2648extra flag argument that tells them to close the file when done.
2649
2650XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002651
Tim Peters8b092332000-09-05 20:15:25 +00002652
2653Windows Changes
2654---------------
2655
2656New popen2/popen3/peopen4 in os module (see Changed Modules above).
2657
2658os.popen is much more usable on Windows 95 and 98. See Microsoft
2659Knowledge Base article Q150956. The Win9x workaround described there
2660is implemented by the new w9xpopen.exe helper in the root of your
2661Python installation. Note that Python uses this internally; it is not
2662a standalone program.
2663
2664Administrator privileges are no longer required to install Python
2665on Windows NT or Windows 2000. If you have administrator privileges,
2666Python's registry info will be written under HKEY_LOCAL_MACHINE.
2667Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002668under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002669uses of Python, but will prevent some advanced uses from working
2670(for example, running a Python script as an NT service, or possibly
2671from CGI).
2672
2673[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2674installer; instead, it installs the needed Tcl/Tk files directly in the
2675Python directory. If you already have a Tcl/Tk installation, this
2676wastes some disk space (about 4 Megs) but avoids problems with
2677conflicting Tcl/Tk installations, and makes it much easier for Python
2678to ensure that Tcl/Tk can find all its files.
2679
2680[This was new in 1.6] The Windows installer now installs by default in
2681\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2682
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002683
2684Updates to the changes between 1.5.2 and 1.6
2685--------------------------------------------
2686
2687The 1.6 NEWS file can't be changed after the release is done, so here
2688is some late-breaking news:
2689
2690New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2691and changes to getlocale() and setlocale().
2692
2693The new module is now enabled per default.
2694
2695It is not true that the encodings codecs cannot be used for normal
2696strings: the string.encode() (which is also present on 8-bit strings
2697!) allows using them for 8-bit strings too, e.g. to convert files from
2698cp1252 (Windows) to latin-1 or vice-versa.
2699
2700Japanese codecs are available from Tamito KAJIYAMA:
2701http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2702
2703
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002704======================================================================