blob: 690759b1709ffc23e9012a6e3c8c2281230566d2 [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
Tim Petersabf925f2001-09-28 21:53:42 +000023Core
24
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
Martin v. Löwis16dc7f42001-09-30 20:32:11 +000034- binascii has now two quopri support functions, a2b_qp and b2a_qp.
35
Martin v. Löwis0daad592001-09-30 21:09:59 +000036- readline now supports setting the startup_hook and the pre_event_hook.
37
Martin v. Löwis16628c92001-10-04 22:46:41 +000038- posix supports chroot where available.
39
Tim Petersabf925f2001-09-28 21:53:42 +000040Library
41
Tim Peters7402f792001-10-02 03:53:41 +000042- doctest now excludes functions and classes not defined by the module
43 being tested, thanks to Tim Hochberg.
44
Guido van Rossumc4b09b42001-10-04 10:19:00 +000045- profile now produces correct output in situations where an exception
46 raised in Python is cleared by C code (e.g. hasattr()). This used
47 to cause wrong output, including spurious claims of recursive
48 functions and attribution of time spent to the wrong function.
49
Tim Peters0a1fc4e2001-10-07 03:12:08 +000050 The code and documentation for the derived OldProfile and HotProfile
51 profiling classes was removed. The code hasn't worked for years (if
52 you tried to use them, they raised exceptions). OldProfile
53 intended to reproduce the behavior of the profiler Python used more
54 than 7 years ago, and isn't interesting anymore. HotProfile intended
55 to provide a faster profiler (but producing less information), and
56 that's a worthy goal we intend to meet via a different approach (but
57 without losing information).
58
Tim Peterscce092d2001-10-09 05:31:56 +000059- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +000060 a much better system-specific calibration constant. The constant can
61 now be specified in an instance constructor, or as a Profile class or
62 instance variable, instead of by editing profile.py's source code.
63 Calibration must still be done manually (see the docs for the profile
64 module).
65
66 Note that Profile.calibrate() must be overriden by subclasses.
67 Improving the accuracy required exploiting detailed knowledge of
68 profiler internals; the earlier method abstracted away the details
69 and measured a simplified model instead, but consequently computed
70 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +000071
Martin v. Löwis16dc7f42001-09-30 20:32:11 +000072- quopri's encode and decode methods take an optional header parameter,
Jeremy Hylton6f543b62001-10-16 20:42:52 +000073 which indicates whether output is intended for the header 'Q'
74 encoding.
75
76- Decompression objects in the zlib module now accept an optional
77 second parameter to decompress() that specifies the maximum amount
78 of memory to use for the uncompressed data.
Martin v. Löwis16dc7f42001-09-30 20:32:11 +000079
Guido van Rossumed554f62001-10-02 23:15:37 +000080Tools/Demos
81
82- Demo/dns was removed. It no longer serves any purpose; a package
83 derived from it is now maintained by Anthony Baxter, see
84 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +000085
86Build
87
88C API
89
Tim Petersd38b1c72001-09-30 05:09:37 +000090- PyLong_AsLongLong() now accepts int (as well as long) arguments.
91 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
92 as long) arguments.
93
Tim Petersabf925f2001-09-28 21:53:42 +000094New platforms
95
96Tests
97
98Windows
99
Tim Peters04cf1d32001-10-09 22:39:40 +0000100- Installer: If you install IDLE, and don't disable file-extension
101 registration, a new "Edit with IDLE" context (right-click) menu entry
102 is created for .py and .pyw files.
103
Tim Peters1ce3cf72001-10-01 17:58:40 +0000104- The signal module now supports SIGBREAK on Windows, thanks to Steven
105 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
106 action remains to call Win32 ExitProcess(). This can be changed via
107 signal.signal(). For example:
108
109 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
110 # (SIGINT) behavior.
111 import signal
112 signal.signal(signal.SIGBREAK,
113 signal.default_int_handler)
114
115 try:
116 while 1:
117 pass
118 except KeyboardInterrupt:
119 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
120 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
121 # program without the possibility for any Python-level cleanup).
122 print "Clean exit"
123
Tim Petersabf925f2001-09-28 21:53:42 +0000124
Tim Petersb07352e2001-09-08 01:25:47 +0000125What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000126Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000127===========================
128
Guido van Rossum808eea72001-09-25 04:15:41 +0000129Type/class unification and new-style classes
130
131- pydoc and inspect are now aware of new-style classes;
132 e.g. help(list) at the interactive prompt now shows proper
133 documentation for all operations on list objects.
134
135- Applications using Jim Fulton's ExtensionClass module can now safely
136 be used with Python 2.2. In particular, Zope 2.4.1 now works with
137 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
138 examples also work again. It is hoped that Gtk and Boost also work
139 with 2.2a4 and beyond. (If you can confirm this, please write
140 webmaster@python.org; if there are still problems, please open a bug
141 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000142
Tim Peters66c1a522001-09-24 21:17:50 +0000143- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
144 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
145 in the constructed property object. fget, fset and fdel weren't
146 discoverable from Python in 2.2a3. __doc__ is new, and allows to
147 associate a docstring with a property.
148
Guido van Rossum808eea72001-09-25 04:15:41 +0000149- Comparison overloading is now more completely implemented. For
150 example, a str subclass instance can properly be compared to a str
151 instance, and it can properly overload comparison. Ditto for most
152 other built-in object types.
153
154- The repr() of new-style classes has changed; instead of <type
155 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
156 *except* for built-in types, which are still rendered as <type
157 'Foo'> (to avoid upsetting existing code that might parse or
158 otherwise rely on repr() of certain type objects).
159
160- The repr() of new-style objects is now always <Foo object at XXX>;
161 previously, it was sometimes <Foo instance at XXX>.
162
163- For new-style classes, what was previously called __getattr__ is now
164 called __getattribute__. This method, if defined, is called for
165 *every* attribute access. A new __getattr__ hook mor similar to the
166 one in classic classes is defined which is called only if regular
167 attribute access raises AttributeError; to catch *all* attribute
168 access, you can use __getattribute__ (for new-style classes). If
169 both are defined, __getattribute__ is called first, and if it raises
170 AttributeError, __getattr__ is called.
171
172- The __class__ attribute of new-style objects can be assigned to.
173 The new class must have the same C-level object layout as the old
174 class.
175
176- The builtin file type can be subclassed now. In the usual pattern,
177 "file" is the name of the builtin type, and file() is a new builtin
178 constructor, with the same signature as the builtin open() function.
179 file() is now the preferred way to open a file.
180
181- Previously, __new__ would only see sequential arguments passed to
182 the type in a constructor call; __init__ would see both sequential
183 and keyword arguments. This made no sense whatsoever any more, so
184 now both __new__ and __init__ see all arguments.
185
186- Previously, hash() applied to an instance of a subclass of str or
187 unicode always returned 0. This has been repaired.
188
189- Previously, an operation on an instance of a subclass of an
190 immutable type (int, long, float, complex, tuple, str, unicode),
191 where the subtype didn't override the operation (and so the
192 operation was handled by the builtin type), could return that
193 instance instead a value of the base type. For example, if s was of
194 a str sublass type, s[:] returned s as-is. Now it returns a str
195 with the same value as s.
196
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000197- Provisional support for pickling new-style objects has been added.
198
Guido van Rossum808eea72001-09-25 04:15:41 +0000199Core
200
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000201- file.writelines() now accepts any iterable object producing strings.
202
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000203- PyUnicode_FromEncodedObject() now works very much like
204 PyObject_Str(obj) in that it tries to use __str__/tp_str
205 on the object if the object is not a string or buffer. This
206 makes unicode() behave like str() when applied to non-string/buffer
207 objects.
208
Martin v. Löwis2777c022001-09-19 13:47:32 +0000209- PyFile_WriteObject now passes Unicode object to the file's write
210 method. As a result, all file-like object which may be the target
211 of a print statement must support Unicode objects, i.e. they must
212 at least convert them into ASCII strings.
213
Guido van Rossum624c8af2001-09-18 15:21:04 +0000214- Thread scheduling on Solaris should be improved; it is no longer
215 necessary to insert a small sleep at the start of a thread in order
216 to let other runnable threads be scheduled.
217
Tim Petersb07352e2001-09-08 01:25:47 +0000218Library
219
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000220- StringIO.StringIO instances and cStringIO.StringIO instances support
221 read character buffer compatible objects for their .write() methods.
222 These objects are converted to strings and then handled as such
223 by the instances.
224
Barry Warsaw2f600732001-09-24 04:28:10 +0000225- The "email" package has been added. This is basically a port of the
226 mimelib package <http://sf.net/projects/mimelib> with API changes
227 and some implementations updated to use iterators and generators.
228
Tim Peters8a9c2842001-09-22 21:30:22 +0000229- difflib.ndiff() and difflib.Differ.compare() are generators now. This
230 restores the ability of Tools/scripts/ndiff.py to start producing output
231 before the entire comparison is complete.
232
Barry Warsaw58b072d2001-09-22 04:44:21 +0000233- StringIO.StringIO instances and cStringIO.StringIO instances support
234 iteration just like file objects (i.e. their .readline() method is
235 called for each iteration until it returns an empty string).
236
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000237- The codecs module has grown four new helper APIs to access
238 builtin codecs: getencoder(), getdecoder(), getreader(),
239 getwriter().
240
Guido van Rossum624c8af2001-09-18 15:21:04 +0000241- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
242 simplifies writing XML RPC servers.
243
Barry Warsaw647d5e82001-09-28 17:01:02 +0000244- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000245 after interpretation of symbolic links. On non-Unix systems, this
246 is an alias for os.path.abspath().
247
Tim Peters16a77ad2001-09-08 04:00:12 +0000248- operator.indexOf() (PySequence_Index() in the C API) now works with any
249 iterable object.
250
Guido van Rossum624c8af2001-09-18 15:21:04 +0000251- smtplib now supports various authentication and security features of
252 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000253
Guido van Rossum624c8af2001-09-18 15:21:04 +0000254- hmac: a new module implementing keyed hashing for message
255 authentication.
256
257- mimetypes now recognizes more extensions and file types. At the
258 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000259
Guido van Rossum624c8af2001-09-18 15:21:04 +0000260- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000261 Python 2.2 bytecode generation. It has also been promoted from a
262 Tool to a standard library package. (Tools/compiler still exists as
263 a sample driver.)
264
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000265Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000266
Tim Petersb07352e2001-09-08 01:25:47 +0000267Build
268
Guido van Rossum624c8af2001-09-18 15:21:04 +0000269- Large file support (LFS) is now automatic when the platform supports
270 it; no more manual configuration tweaks are needed. On Linux, at
271 least, it's possible to have a system whose C library supports large
272 files but whose kernel doesn't; in this case, large file support is
273 still enabled but doesn't do you any good unless you upgrade your
274 kernel or share your Python executable with another system whose
275 kernel has large file support.
276
277- The configure script now supplies plausible defaults in a
278 cross-compilation environment. This doesn't mean that the supplied
279 values are always correct, or that cross-compilation now works
280 flawlessly -- but it's a first step (and it shuts up most of
281 autoconf's warnings about AC_TRY_RUN).
282
283- The Unix build is now a bit less chatty, courtesy of the parser
284 generator. The build is completely silent (except for errors) when
285 using "make -s", thanks to a -q option to setup.py.
286
Tim Petersb07352e2001-09-08 01:25:47 +0000287C API
288
Guido van Rossum624c8af2001-09-18 15:21:04 +0000289- The "structmember" API now supports some new flag bits to deny read
290 and/or write access to attributes in restricted execution mode.
291
Tim Petersb07352e2001-09-08 01:25:47 +0000292New platforms
293
Guido van Rossum624c8af2001-09-18 15:21:04 +0000294- Compaq's iPAQ handheld, running the "familiar" Linux distribution
295 (http://familiar.handhelds.org).
296
Tim Petersb07352e2001-09-08 01:25:47 +0000297Tests
298
Tim Peters8a9c2842001-09-22 21:30:22 +0000299- The "classic" standard tests, which work by comparing stdout to
300 an expected-output file under Lib/test/output/, no longer stop at
301 the first mismatch. Instead the test is run to completion, and a
302 variant of ndiff-style comparison is used to report all differences.
303 This is much easier to understand than the previous style of reporting.
304
305- The unittest-based standard tests now use regrtest's test_main()
306 convention, instead of running as a side-effect of merely being
307 imported. This allows these tests to be run in more natural and
308 flexible ways as unittests, outside the regrtest framework.
309
310- regrtest.py is much better integrated with unittest and doctest now,
311 especially in regard to reporting errors.
312
Tim Petersb07352e2001-09-08 01:25:47 +0000313Windows
314
Guido van Rossum624c8af2001-09-18 15:21:04 +0000315- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000316 that support it (NTFS under Windows 2000). See "What's New in
317 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000318
Tim Petersb07352e2001-09-08 01:25:47 +0000319
Tim Petersedc99312001-08-22 21:36:50 +0000320What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000321Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000322===========================
323
324Core
325
Tim Peters9fffa3e2001-09-04 05:14:19 +0000326- Conversion of long to float now raises OverflowError if the long is too
327 big to represent as a C double.
328
Tim Peters32f453e2001-09-03 08:35:41 +0000329- The 3-argument builtin pow() no longer allows a third non-None argument
330 if either of the first two arguments is a float, or if both are of
331 integer types and the second argument is negative (in which latter case
332 the arguments are converted to float, so this is really the same
333 restriction).
334
Tim Peters5d2b77c2001-09-03 05:47:38 +0000335- The builtin dir() now returns more information, and sometimes much
336 more, generally naming all attributes of an object, and all attributes
337 reachable from the object via its class, and from its class's base
338 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
339 an empty list. In 2.2a3,
340
341 >>> dir([])
342 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
343 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
344 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
345 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
346 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
347 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
348 'reverse', 'sort']
349
350 dir(module) continues to return only the module's attributes, though.
351
Tim Petersbdee63f2001-09-02 03:40:59 +0000352- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000353 than raising OverflowError. This is a partial implementation of PEP
354 237. You can use -Wdefault::OverflowWarning to enable a warning for
355 this situation, and -Werror::OverflowWarning to revert to the old
356 OverflowError exception.
357
Guido van Rossum61c345f2001-09-04 03:26:15 +0000358- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000359 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000360 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
361 -Qold, meaning the / operator has its classic meaning and no
362 warnings are issued. Using -Qwarn issues a run-time warning about
363 all uses of classic division for int and long arguments; -Qwarnall
364 also warns about classic division for float and complex arguments
365 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
366 new division by default, but only in the __main__ module. You can
367 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
368 __main__ module new division, and warns about classic division
369 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000370
Tim Petersbdee63f2001-09-02 03:40:59 +0000371- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000372 long, float, str, unicode, and tuple. (The types complex, list and
373 dictionary can also be subclassed; this was introduced earlier.)
374 Note that restrictions apply when subclassing immutable built-in
375 types: you can only affect the value of the instance by overloading
376 __new__. You can add mutable attributes, and the subclass instances
377 will have a __dict__ attribute, but you cannot change the "value"
378 (as implemented by the base class) of an immutable subclass instance
379 once it is created.
380
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000381- The dictionary constructor now takes an optional argument, a
382 mapping-like object, and initializes the dictionary from its
383 (key, value) pairs.
384
Tim Petersbdee63f2001-09-02 03:40:59 +0000385- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000386 "cooperative super calls" in a multiple inheritance setting. For an
387 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
388
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000389- A new built-in type, property, has been added. This enables the
390 creation of "properties". These are attributes implemented by
391 getter and setter functions (or only one of these for read-only or
392 write-only attributes), without the need to override __getattr__.
393 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000394
Tim Petersbdee63f2001-09-02 03:40:59 +0000395- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000396 liberalized, to allow leading zeroes. Examples of literals now
397 legal that were SyntaxErrors before:
398
399 00.0 0e3 0100j 07.5 00000000000000000008.
400
Tim Petersbdee63f2001-09-02 03:40:59 +0000401- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000402 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
403
Tim Petersedc99312001-08-22 21:36:50 +0000404Library
405
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000406- telnetlib includes symbolic names for the options, and support for
407 setting an option negotiation callback.
408
Tim Petersa40c7932001-09-05 22:36:56 +0000409- The new C standard no longer requires that math libraries set errno to
410 ERANGE on overflow. For platform libraries that exploit this new
411 freedom, Python's overflow-checking was wholly broken. A new overflow-
412 checking scheme attempts to repair that, but may not be reliable on all
413 platforms (C doesn't seem to provide anything both useful and portable
414 in this area anymore).
415
Martin v. Löwis44f86962001-09-05 13:44:54 +0000416- Asynchronous timeout actions are available through the new class
417 threading.Timer.
418
Tim Peters78526162001-09-05 00:53:45 +0000419- math.log and math.log10 now return sensible results for even huge
420 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
421
Tim Petersbdee63f2001-09-02 03:40:59 +0000422- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000423 currently held. See the docs for the imp module.
424
Tim Petersbdee63f2001-09-02 03:40:59 +0000425- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000426 dumps containing ints written on platforms where Python ints are 8 bytes.
427 When read on a box where Python ints are 4 bytes, such values are
428 converted to Python longs.
429
Tim Petersbdee63f2001-09-02 03:40:59 +0000430- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000431 code objects is no longer allowed. This plugs a security hole.
432
Steve Purcell6091cd62001-09-06 16:05:17 +0000433- unittest.TestResult instances no longer store references to tracebacks
434 generated by test failures. This prevents unexpected dangling references
435 to objects that should be garbage collected between tests.
436
Tim Petersedc99312001-08-22 21:36:50 +0000437Tools
438
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000439- Tools/scripts/fixdiv.py has been added which can be used to fix
440 division operators as per PEP 238.
441
Tim Petersedc99312001-08-22 21:36:50 +0000442Build
443
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000444- If you are an adventurous person using Mac OS X you may want to look at
445 Mac/OSX. There is a Makefile there that will build Python as a real Mac
446 application, which can be used for experimenting with Carbon or Cocoa.
447 Discussion of this on pythonmac-sig, please.
448
Tim Peters7eea37e2001-09-04 22:08:56 +0000449C API
450
451- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000452
Tim Peters9fffa3e2001-09-04 05:14:19 +0000453- Note that PyLong_AsDouble can fail! This has always been true, but no
454 callers checked for it. It's more likely to fail now, because overflow
455 errors are properly detected now. The proper way to check:
456
457 double x = PyLong_AsDouble(some_long_object);
458 if (x == -1.0 && PyErr_Occurred()) {
459 /* The conversion failed. */
460 }
461
Tim Petersbdee63f2001-09-02 03:40:59 +0000462- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000463 compile but will not participate in GC. To upgrade an extension
464 module:
465
466 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000467
Neil Schemenauer4042c692001-08-30 15:38:01 +0000468 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
469 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000470
Neil Schemenauer4042c692001-08-30 15:38:01 +0000471 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
472 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000473
Neil Schemenauer4042c692001-08-30 15:38:01 +0000474 - remove PyGC_HEAD_SIZE from object size calculations
475
476 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
477
Tim Petersbdee63f2001-09-02 03:40:59 +0000478- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000479 These can be used safely to construct string objects from a
480 sprintf-style format string (similar to the format string supported
481 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000482
Tim Petersedc99312001-08-22 21:36:50 +0000483New platforms
484
Tim Petersb7da0902001-09-02 23:01:43 +0000485- Stephen Hansen contributed patches sufficient to get a clean compile
486 under Borland C (Windows), but he reports problems running it and ran
487 out of time to complete the port. Volunteers? Expect a MemoryError
488 when importing the types module; this is probably shallow, and
489 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000490
Tim Petersedc99312001-08-22 21:36:50 +0000491Tests
492
493Windows
494
Tim Peters6e13a562001-09-06 00:32:15 +0000495- Large file support is now enabled on Win32 platforms as well as on
496 Win64. This means that, for example, you can use f.tell() and f.seek()
497 to manipulate files larger than 2 gigabytes (provided you have enough
498 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000499 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
500 filesize limit, and large file support makes no difference there.
501 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
502 NTFS has no practical limit on file size, and files of any size can be
503 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000504
Tim Petersbdee63f2001-09-02 03:40:59 +0000505- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000506 points to command.com (patch from Brian Quinlan).
507
Tim Petersedc99312001-08-22 21:36:50 +0000508
Tim Peters20f51a72001-07-21 02:31:40 +0000509What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000510Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000511===========================
512
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000513Build
514
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000515- Tim Peters developed a brand new Windows installer using Wise 8.1,
516 generously donated to us by Wise Solutions.
517
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000518- configure supports a new option --enable-unicode, with the values
519 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
520 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000521
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000522- A new configure option --enable-framework builds a Mac OS X framework,
523 which "make frameworkinstall" will install. This provides a starting
524 point for more mac-like functionality, join pythonmac-sig@python.org
525 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000526
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000527- The NeXT platform is no longer supported.
528
529- The `new' module is now statically linked.
530
Tim Peters0afb6092001-08-15 06:06:44 +0000531Tools
532
533- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000534 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000535 the module docstring for details.
536
Tim Peters20f51a72001-07-21 02:31:40 +0000537Tests
538
Tim Peters5e824c32001-08-12 22:25:01 +0000539- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000540 platforms, allowing to give clearer test result output. regrtest
541 also has optional --use/-u switch to run normally disabled tests
542 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000543
Tim Peters20f51a72001-07-21 02:31:40 +0000544- Several new tests in the standard test suite, with special thanks to
545 Nick Mathewson.
546
547Core
548
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000549- The floor division operator // has been added as outlined in PEP
550 238. The / operator still provides classic division (and will until
551 Python 3.0) unless "from __future__ import division" is included, in
552 which case the / operator will provide true division. The operator
553 module provides truediv() and floordiv() functions. Augmented
554 assignment variants are included, as are the equivalent overloadable
555 methods and C API methods. See the PEP for a full discussion:
556 <http://python.sf.net/peps/pep-0238.html>
557
Tim Peters6cd6a822001-08-17 22:11:27 +0000558- Future statements are now effective in simulated interactive shells
559 (like IDLE). This should "just work" by magic, but read Michael
560 Hudson's "Future statements in simulated shells" PEP 264 for full
561 details: <http://python.sf.net/peps/pep-0264.html>.
562
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000563- The type/class unification (PEP 252-253) was integrated into the
564 trunk and is not so tentative any more (the exact specification of
565 some features is still tentative). A lot of work has done on fixing
566 bugs and adding robustness and features (performance still has to
567 come a long way).
568
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000569- Warnings about a mismatch in the Python API during extension import
570 now use the Python warning framework (which makes it possible to
571 write filters for these warnings).
572
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000573- A function's __dict__ (aka func_dict) will now always be a
574 dictionary. It used to be possible to delete it or set it to None,
575 but now both actions raise TypeErrors. It is still legal to set it
576 to a dictionary object. Getting func.__dict__ before any attributes
577 have been assigned now returns an empty dictionary instead of None.
578
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000579- A new command line option, -E, was added which disables the use of
580 all environment variables, or at least those that are specifically
581 significant to Python. Usually those have a name starting with
582 "PYTHON". This was used to fix a problem where the tests fail if
583 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
584 older distribution.
585
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000586Library
587
Tim Peters5e824c32001-08-12 22:25:01 +0000588- New class Differ and new functions ndiff() and restore() in difflib.py.
589 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000590 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000591
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000592- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
593 value using the minimal quoting required for the value; more
594 reliable than using xml.sax.saxutils.escape() for attribute values.
595
596- Readline completion support for cmd.Cmd was added.
597
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000598- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
599
600- Added function threading.BoundedSemaphore()
601
602- Added Ka-Ping Yee's cgitb.py module.
603
604- The `new' module now exposes the CO_xxx flags.
605
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000606New platforms
607
608C API
609
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000610- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
611 which provide a cross-platform implementations for the
612 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
613 the standard sprintf() and vsprintf() C lib APIs, these versions
614 apply bounds checking on the used buffer which enhances protection
615 against buffer overruns.
616
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000617- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000618 and extensions using different Unicode widths is rendered next to
619 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000620 will result in an ImportError. Unicode extensions writers must make
621 sure to check the Unicode width compatibility in their extensions by
622 using at least one of the mangled Unicode APIs in the extension.
623
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000624- Two new flags METH_NOARGS and METH_O are available in method definition
625 tables to simplify implementation of methods with no arguments and a
626 single untyped argument. Calling such methods is more efficient than
627 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
628 deprecated.
629
Tim Petersc1731372001-08-04 08:12:36 +0000630Windows
631
632- "import module" now compiles module.pyw if it exists and nothing else
633 relevant is found.
634
Tim Peters20f51a72001-07-21 02:31:40 +0000635
Guido van Rossum55a78992001-07-17 17:22:32 +0000636What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +0000637===========================
638
639Core
Tim Petersa814db52001-05-14 07:05:58 +0000640
Tim Peters6d6c1a32001-08-02 04:15:00 +0000641- TENTATIVELY, a large amount of code implementing much of what's
642 described in PEP 252 (Making Types Look More Like Classes) and PEP
643 253 (Subtyping Built-in Types) was added. This will be released
644 with Python 2.2a1. Documentation will be provided separately
645 through http://www.python.org/2.2/. The purpose of releasing this
646 with Python 2.2a1 is to test backwards compatibility. It is
647 possible, though not likely, that a decision is made not to release
648 this code as part of 2.2 final, if any serious backwards
649 incompapatibilities are found during alpha testing that cannot be
650 repaired.
651
Guido van Rossum55a78992001-07-17 17:22:32 +0000652- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000653 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000654 more 'yield' statements. See PEP 255. Since this adds a new
655 keyword to the language, this feature must be enabled by including a
656 future statement: "from __future__ import generators" (see PEP 236).
657 Generators will become a standard feature in a future release
658 (probably 2.3). Without this future statement, 'yield' remains an
659 ordinary identifier, but a warning is issued each time it is used.
660 (These warnings currently don't conform to the warnings framework of
661 PEP 230; we intend to fix this in 2.2a2.)
662
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000663- The UTF-16 codec was modified to be more RFC compliant. It will now
664 only remove BOM characters at the start of the string and then
665 only if running in native mode (UTF-16-LE and -BE won't remove a
666 leading BMO character).
667
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000668- Strings now have a new method .decode() to complement the already
669 existing .encode() method. These two methods provide direct access
670 to the corresponding decoders and encoders of the registered codecs.
671
672 To enhance the usability of the .encode() method, the special
673 casing of Unicode object return values was dropped (Unicode objects
674 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000675
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000676 Both methods will now return whatever the codec in charge of the
677 requested encoding returns as object, e.g. Unicode codecs will
678 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
679 will return u"äöü"). This enables codec writer to create codecs
680 for various simple to use conversions.
681
682 New codecs were added to demonstrate these new features (the .encode()
683 and .decode() columns indicate the type of the returned objects):
684
685 Name | .encode() | .decode() | Description
686 ----------------------------------------------------------------------
687 uu | string | string | UU codec (e.g. for email)
688 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000689 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000690 zlib | string | string | zlib compression
691 hex | string | string | 2-byte hex codec
692 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
693
Mark Hammond2a0af792001-05-14 03:09:36 +0000694- Some operating systems now support the concept of a default Unicode
695 encoding for file system operations. Notably, Windows supports 'mbcs'
696 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000697 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000698 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000699
700 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000701 functions that return filenames (such as os.listdir()) to return Python
702 string objects pre-encoded using the default file system encoding for
703 the platform. As this encoding is likely to be different from Python's
704 default encoding, converting this name to a Unicode object before passing
705 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000706 would attempt to use its default encoding (generally ASCII) rather than
707 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000708
Tim Petersa814db52001-05-14 07:05:58 +0000709 In general, this change simply removes surprises when working with
710 Unicode and the file system, making these operations work as you expect,
711 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000712 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000713
Tim Peters61dff2b2001-05-08 15:43:37 +0000714- Float (and complex) literals in source code were evaluated to full
715 precision only when running from a .py file; the same code loaded from a
716 .pyc (or .pyo) file could suffer numeric differences starting at about the
717 12th significant decimal digit. For example, on a machine with IEEE-754
718 floating arithmetic,
719
720 x = 9007199254740992.0
721 print long(x)
722
723 printed 9007199254740992 if run directly from .py, but 9007199254740000
724 if from a compiled (.pyc or .pyo) file. This was due to marshal using
725 str(float) instead of repr(float) when building code objects. marshal
726 now uses repr(float) instead, which should reproduce floats to full
727 machine precision (assuming the platform C float<->string I/O conversion
728 functions are of good quality).
729
730 This may cause floating-point results to change in some cases, and
731 usually for the better, but may also cause numerically unstable
732 algorithms to break.
733
Tim Peters2f228e72001-05-13 00:19:31 +0000734- The implementation of dicts suffers fewer collisions, which has speed
735 benefits. However, the order in which dict entries appear in dict.keys(),
736 dict.values() and dict.items() may differ from previous releases for a
737 given dict. Nothing is defined about this order, so no program should
738 rely on it. Nevertheless, it's easy to write test cases that rely on the
739 order by accident, typically because of printing the str() or repr() of a
740 dict to an "expected results" file. See Lib/test/test_support.py's new
741 sortdict(dict) function for a simple way to display a dict in sorted
742 order.
743
Tim Peters7a3bfc32001-06-12 01:22:22 +0000744- Many other small changes to dicts were made, resulting in faster
745 operation along the most common code paths.
746
Guido van Rossum10315822001-05-01 20:54:30 +0000747- Dictionary objects now support the "in" operator: "x in dict" means
748 the same as dict.has_key(x).
749
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000750- The update() method of dictionaries now accepts generic mapping
751 objects. Specifically the argument object must support the .keys()
752 and __getitem__() methods. This allows you to say, for example,
753 {}.update(UserDict())
754
Guido van Rossum10315822001-05-01 20:54:30 +0000755- Iterators were added; this is a generalized way of providing values
756 to a for loop. See PEP 234. There's a new built-in function iter()
757 to return an iterator. There's a new protocol to get the next value
758 from an iterator using the next() method (in Python) or the
759 tp_iternext slot (in C). There's a new protocol to get iterators
760 using the __iter__() method (in Python) or the tp_iter slot (in C).
761 Iterating (i.e. a for loop) over a dictionary generates its keys.
762 Iterating over a file generates its lines.
763
Tim Petersf553f892001-05-01 20:45:31 +0000764- The following functions were generalized to work nicely with iterator
765 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000766 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000767 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
768 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000769 join() method of strings
770 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000771 'x in y' and 'x not in y' (PySequence_Contains() in C API)
772 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000773 right-hand side of assignment statements with multiple targets, such as
774 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000775
Tim Petersd85e1022001-05-11 21:51:48 +0000776- Accessing module attributes is significantly faster (for example,
777 random.random or os.path or yourPythonModule.yourAttribute).
778
Tim Peterse63415e2001-05-08 04:38:29 +0000779- Comparing dictionary objects via == and != is faster, and now works even
780 if the keys and values don't support comparisons other than ==.
781
Tim Peters95bf9392001-05-10 08:32:44 +0000782- Comparing dictionaries in ways other than == and != is slower: there were
783 insecurities in the dict comparison implementation that could cause Python
784 to crash if the element comparison routines for the dict keys and/or
785 values mutated the dicts. Making the code bulletproof slowed it down.
786
Tim Peterseb28ef22001-06-02 05:27:19 +0000787- Collisions in dicts are resolved via a new approach, which can help
788 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000789 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000790 faster now. Thanks to Christian Tismer for pointing out the cause and
791 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000792
Tim Peters52e155e2001-06-16 05:42:57 +0000793- repr() is much faster for large containers (dict, list, tuple).
794
795
Tim Petersa814db52001-05-14 07:05:58 +0000796Library
797
Fred Drake960fdf92001-07-20 18:38:26 +0000798- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
799 were added to the string module. These a locale-indenpendent
800 constants, unlike letters, lowercase, and uppercase. These are now
801 use in appropriate locations in the standard library.
802
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000803- The flags used in dlopen calls can now be configured using
804 sys.setdlopenflags and queried using sys.getdlopenflags.
805
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000806- Fredrik Lundh's xmlrpclib is now a standard library module. This
807 provides full client-side XML-RPC support. In addition,
808 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
809 one asyncore-based). Thanks to Eric Raymond for the documentation.
810
Guido van Rossum643d3912001-07-05 14:46:25 +0000811- The xrange() object is simplified: it no longer supports slicing,
812 repetition, comparisons, efficient 'in' checking, the tolist()
813 method, or the start, stop and step attributes. See PEP 260.
814
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000815- A new function fnmatch.filter to filter lists of file names was added.
816
Barry Warsawffd674d2001-05-22 16:00:10 +0000817- calendar.py uses month and day names based on the current locale.
818
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000819- strop is now *really* obsolete (this was announced before with 1.6),
820 and issues DeprecationWarning when used (except for the four items
821 that are still imported into string.py).
822
Tim Petersa814db52001-05-14 07:05:58 +0000823- Cookie.py now sorts key+value pairs by key in output strings.
824
825- pprint.isrecursive(object) didn't correctly identify recursive objects.
826 Now it does.
827
Tim Peters95b3f782001-05-14 18:39:41 +0000828- pprint functions now much faster for large containers (tuple, list, dict).
829
Tim Peters7b9542a2001-06-10 23:40:19 +0000830- New 'q' and 'Q' format codes in the struct module, corresponding to C
831 types "long long" and "unsigned long long" (on Windows, __int64). In
832 native mode, these can be used only when the platform C compiler supports
833 these types (when HAVE_LONG_LONG is #define'd by the Python config
834 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000835 In standard mode, 'q' and 'Q' are supported on all platforms, and are
836 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000837
Guido van Rossum83213cc2001-06-12 16:48:52 +0000838- The site module installs a new built-in function 'help' that invokes
839 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
840 it displays a message reminding the user to use 'help()' or
841 'help(object)'.
842
Tim Petersa814db52001-05-14 07:05:58 +0000843Tests
844
845- New test_mutants.py runs dict comparisons where the key and value
846 comparison operators mutute the dicts randomly during comparison. This
847 rapidly causes Python to crash under earlier releases (not for the faint
848 of heart: it can also cause Win9x to freeze or reboot!).
849
850- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000851 pprint.isreadable() return sensible results. Also verifies that simple
852 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000853
Tim Peters4324aa32001-05-28 22:30:08 +0000854C API
855
856- Removed the unused last_is_sticky argument from the internal
857 _PyTuple_Resize(). If this affects you, you were cheating.
858
859
Guido van Rossum55a78992001-07-17 17:22:32 +0000860======================================================================
861
862
Guido van Rossumffe13be2001-04-16 18:46:45 +0000863What's New in Python 2.1 (final)?
864=================================
865
866We only changed a few things since the last release candidate, all in
867Python library code:
868
869- A bug in the locale module was fixed that affected locales which
870 define no grouping for numeric formatting.
871
872- A few bugs in the weakref module's implementations of weak
873 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
874 and the test suite was updated to check for these bugs.
875
876- An old bug in the os.path.walk() function (introduced in Python
877 2.0!) was fixed: a non-existent file would cause an exception
878 instead of being ignored.
879
880- Fixed a few bugs in the new symtable module found by Neil Norwitz's
881 PyChecker.
882
883
Guido van Rossum5b08f132001-04-16 02:05:23 +0000884What's New in Python 2.1c2?
885===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000886
Guido van Rossum5b08f132001-04-16 02:05:23 +0000887A flurry of small changes, and one showstopper fixed in the nick of
888time made it necessary to release another release candidate. The list
889here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000890
Guido van Rossum5b08f132001-04-16 02:05:23 +0000891Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000892
Guido van Rossum5b08f132001-04-16 02:05:23 +0000893- Tim discovered a nasty bug in the dictionary code, caused by
894 PyDict_Next() calling dict_resize(), and the GC code's use of
895 PyDict_Next() violating an assumption in dict_items(). This was
896 fixed with considerable amounts of band-aid, but the net effect is a
897 saner and more robust implementation.
898
899- Made a bunch of symbols static that were accidentally global.
900
901Build and Ports
902
903- The setup.py script didn't check for a new enough version of zlib
904 (1.1.3 is needed). Now it does.
905
906- Changed "make clean" target to also remove shared libraries.
907
908- Added a more general warning about the SGI Irix optimizer to README.
909
910Library
911
912- Fix a bug in urllib.basejoin("http://host", "../file.html") which
913 omitted the slash between host and file.html.
914
915- The mailbox module's _Mailbox class contained a completely broken
916 and undocumented seek() method. Ripped it out.
917
918- Fixed a bunch of typos in various library modules (urllib2, smtpd,
919 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
920
921- Fixed a few last-minute bugs in unittest.
922
923Extensions
924
925- Reverted the patch to the OpenSSL code in socketmodule.c to support
926 RAND_status() and the EGD, and the subsequent patch that tried to
927 fix it for pre-0.9.5 versions; the problem with the patch is that on
928 some systems it issues a warning whenever socket is imported, and
929 that's unacceptable.
930
931Tests
932
933- Fixed the pickle tests to work with "import test.test_pickle".
934
935- Tweaked test_locale.py to actually run the test Windows.
936
937- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
938 not "wb" (which is not a valid mode at all).
939
940- Fix pstats browser crashes. Import readline if it exists to make
941 the user interface nicer.
942
943- Add "import thread" to the top of test modules that import the
944 threading module (test_asynchat and test_threadedtempfile). This
945 prevents test failures caused by a broken threading module resulting
946 from a previously caught failed import.
947
948- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
949 needed on some platforms (e.g. Solaris 8) when the tests are run
950 twice in succession.
951
952- Skip rather than fail test_sunaudiodev if no audio device is found.
953
954
955What's New in Python 2.1c1?
956===========================
957
958This list was significantly updated when 2.1c2 was released; the 2.1c1
959release didn't mention most changes that were actually part of 2.1c1:
960
961Legal
962
963- Copyright was assigned to the Python Software Foundation (PSF) and a
964 PSF license (very similar to the CNRI license) was added.
965
966- The CNRI copyright notice was updated to include 2001.
967
968Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000969
Guido van Rossumc9932722001-04-12 02:31:27 +0000970- After a public outcry, assignment to __debug__ is no longer illegal;
971 instead, a warning is issued. It will become illegal in 2.2.
972
Guido van Rossum5b08f132001-04-16 02:05:23 +0000973- Fixed a core dump with "%#x" % 0, and changed the semantics so that
974 "%#x" now always prepends "0x", even if the value is zero.
975
976- Fixed some nits in the bytecode compiler.
977
978- Fixed core dumps when calling certain kinds of non-functions.
979
980- Fixed various core dumps caused by reference count bugs.
981
982Build and Ports
983
984- Use INSTALL_SCRIPT to install script files.
985
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000986- New port: SCO Unixware 7, by Billy G. Allie.
987
Guido van Rossum5b08f132001-04-16 02:05:23 +0000988- Updated RISCOS port.
989
990- Updated BeOS port and notes.
991
992- Various other porting problems resolved.
993
994Library
995
996- The TERMIOS and SOCKET modules are now truly obsolete and
997 unnecessary. Their symbols are incorporated in the termios and
998 socket modules.
999
1000- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
1001 better tests for pickling.
1002
1003- threading: make Condition.wait() robust against KeyboardInterrupt.
1004
1005- zipfile: add support to zipfile to support opening an archive
1006 represented by an open file rather than a file name. Fix bug where
1007 the archive was not properly closed. Fixed a bug in this bugfix
1008 where flush() was called for a read-only file.
1009
1010- imputil: added an uninstall() method to the ImportManager.
1011
1012- Canvas: fixed bugs in lower() and tkraise() methods.
1013
1014- SocketServer: API change (added overridable close_request() method)
1015 so that the TCP server can explicitly close the request.
1016
1017- pstats: Eric Raymond added a simple interactive statistics browser,
1018 invoked when the module is run as a script.
1019
1020- locale: fixed a problem in format().
1021
1022- webbrowser: made it work when the BROWSER environment variable has a
1023 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1024 KDE 2. Fixed some other nits.
1025
1026- unittest: changes to allow using a different exception than
1027 AssertionError, and added a few more function aliases. Some other
1028 small changes.
1029
1030- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1031
1032- asynchat: fixed a critical bug in asynchat that slipped through the
1033 2.1b2 release. Fixed another rare bug.
1034
1035- Fix some unqualified except: clauses (always a bad code example).
1036
1037XML
1038
1039- pyexpat: new API get_version_string().
1040
1041- Fixed some minidom bugs.
1042
1043Extensions
1044
1045- Fixed a core dump in _weakref. Removed the weakref.mapping()
1046 function (it adds nothing to the API).
1047
1048- Rationalized the use of header files in the readline module, to make
1049 it compile (albeit with some warnings) with the very recent readline
1050 4.2, without breaking for earlier versions.
1051
1052- Hopefully fixed a buffering problem in linuxaudiodev.
1053
1054- Attempted a fix to make the OpenSSL support in the socket module
1055 work again with pre-0.9.5 versions of OpenSSL.
1056
1057Tests
1058
1059- Added a test case for asynchat and asyncore.
1060
1061- Removed coupling between tests where one test failing could break
1062 another.
1063
1064Tools
1065
1066- Ping added an interactive help browser to pydoc, fixed some nits
1067 in the rest of the pydoc code, and added some features to his
1068 inspect module.
1069
1070- An updated python-mode.el version 4.1 which integrates Ken
1071 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1072 much nicer in XEmacs and Emacs. When stepping through your program
1073 with pdb, in either the shell window or the *Python* window, the
1074 source file and line will be tracked by an arrow. Very cool!
1075
1076- IDLE: syntax warnings in interactive mode are changed into errors.
1077
1078- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001079 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001080
1081- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001082
Barry Warsaw11e89c72001-04-11 20:37:57 +00001083
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001084What's New in Python 2.1 beta 2?
1085================================
1086
Guido van Rossum053ae352001-03-22 14:17:21 +00001087(Unlisted are many fixed bugs, more documentation, etc.)
1088
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001089Core language, builtins, and interpreter
1090
Guido van Rossum053ae352001-03-22 14:17:21 +00001091- The nested scopes work (enabled by "from __future__ import
1092 nested_scopes") is completed; in particular, the future now extends
1093 into code executed through exec, eval() and execfile(), and into the
1094 interactive interpreter.
1095
1096- When calling a base class method (e.g. BaseClass.__init__(self)),
1097 this is now allowed even if self is not strictly spoken a class
1098 instance (e.g. when using metaclasses or the Don Beaudry hook).
1099
1100- Slice objects are now comparable but not hashable; this prevents
1101 dict[:] from being accepted but meaningless.
1102
1103- Complex division is now calculated using less braindead algorithms.
1104 This doesn't change semantics except it's more likely to give useful
1105 results in extreme cases. Complex repr() now uses full precision
1106 like float repr().
1107
1108- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1109
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001110- It is illegal to assign to the name __debug__, which is set when the
1111 interpreter starts. It is effectively a compile-time constant.
1112
1113- A warning will be issued if a global statement for a variable
1114 follows a use or assignment of that variable.
1115
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001116Standard library
1117
Guido van Rossum053ae352001-03-22 14:17:21 +00001118- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1119 inspired by JUnit), is now part of the standard library. You now
1120 have a choice of two testing frameworks: unittest requires you to
1121 write testcases as separate code, doctest gathers them from
1122 docstrings. Both approaches have their advantages and
1123 disadvantages.
1124
1125- A new module Tix was added, which wraps the Tix extension library
1126 for Tk. With that module, it is not necessary to statically link
1127 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1128 require" command. See Demo/tix/.
1129
1130- tzparse.py is now obsolete.
1131
1132- In gzip.py, the seek() and tell() methods are removed -- they were
1133 non-functional anyway, and it's better if callers can test for their
1134 existence with hasattr().
1135
1136Python/C API
1137
1138- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1139 that's already in the dictionary during a PyDict_Next() iteration.
1140 This used to fail occasionally when a dictionary resize operation
1141 could be triggered that would rehash all the keys. All other
1142 modifications to the dictionary are still off-limits during a
1143 PyDict_Next() iteration!
1144
1145- New extended APIs related to passing compiler variables around.
1146
1147- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1148 implement isinstance() and issubclass().
1149
1150- Py_BuildValue() now has a "D" conversion to create a Python complex
1151 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001152
Fred Drake4e262a92001-03-22 18:26:47 +00001153- Extensions types which support weak references must now set the
1154 field allocated for the weak reference machinery to NULL themselves;
1155 this is done to avoid the cost of checking each object for having a
1156 weakly referencable type in PyObject_INIT(), since most types are
1157 not weakly referencable.
1158
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001159- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1160 free variables and cell variables to and from the frame's f_locals.
1161
1162- Variants of several functions defined in pythonrun.h have been added
1163 to support the nested_scopes future statement. The variants all end
1164 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1165 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1166 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001167 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001168
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001169Distutils
1170
1171- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1172 into the release tree.
1173
Tim Peters0e57abf2001-05-02 07:39:38 +00001174- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001175 (an uninstaller, more customization of the installer's display)
1176
1177- from Jack Jansen: added Mac-specific code to generate a dialog for
1178 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001179 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001180 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001181
1182- added 'platforms' and 'keywords' to the set of metadata that can be
1183 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001184
1185- applied patches from Jason Tishler to make the compiler class work with
1186 Cygwin.
1187
1188
Tim Peters2fe289a2001-03-01 22:19:38 +00001189What's New in Python 2.1 beta 1?
1190================================
Tim Petersd66595f2001-02-04 03:09:53 +00001191
1192Core language, builtins, and interpreter
1193
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001194- Following an outcry from the community about the amount of code
1195 broken by the nested scopes feature introduced in 2.1a2, we decided
1196 to make this feature optional, and to wait until Python 2.2 (or at
1197 least 6 months) to make it standard. The option can be enabled on a
1198 per-module basis by adding "from __future__ import nested_scopes" at
1199 the beginning of a module (before any other statements, but after
1200 comments and an optional docstring). See PEP 236 (Back to the
1201 __future__) for a description of the __future__ statement. PEP 227
1202 (Statically Nested Scopes) has been updated to reflect this change,
1203 and to clarify the semantics in a number of endcases.
1204
1205- The nested scopes code, when enabled, has been hardened, and most
1206 bugs and memory leaks in it have been fixed.
1207
1208- Compile-time warnings are now generated for a number of conditions
1209 that will break or change in meaning when nested scopes are enabled:
1210
1211 - Using "from...import *" or "exec" without in-clause in a function
1212 scope that also defines a lambda or nested function with one or
1213 more free (non-local) variables. The presence of the import* or
1214 bare exec makes it impossible for the compiler to determine the
1215 exact set of local variables in the outer scope, which makes it
1216 impossible to determine the bindings for free variables in the
1217 inner scope. To avoid the warning about import *, change it into
1218 an import of explicitly name object, or move the import* statement
1219 to the global scope; to avoid the warning about bare exec, use
1220 exec...in... (a good idea anyway -- there's a possibility that
1221 bare exec will be deprecated in the future).
1222
1223 - Use of a global variable in a nested scope with the same name as a
1224 local variable in a surrounding scope. This will change in
1225 meaning with nested scopes: the name in the inner scope will
1226 reference the variable in the outer scope rather than the global
1227 of the same name. To avoid the warning, either rename the outer
1228 variable, or use a global statement in the inner function.
1229
Neil Schemenauera35c6882001-02-27 04:45:05 +00001230- An optional object allocator has been included. This allocator is
1231 optimized for Python objects and should be faster and use less memory
1232 than the standard system allocator. It is not enabled by default
1233 because of possible thread safety problems. The allocator is only
1234 protected by the Python interpreter lock and it is possible that some
1235 extension modules require a thread safe allocator. The object
1236 allocator can be enabled by providing the "--with-pymalloc" option to
1237 configure.
1238
Tim Petersd66595f2001-02-04 03:09:53 +00001239Standard library
1240
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001241- pyexpat now detects the expat version if expat.h defines it. A
1242 number of additional handlers are provided, which are only available
1243 since expat 1.95. In addition, the methods SetParamEntityParsing and
1244 GetInputContext of Parser objects are available with 1.95.x
1245 only. Parser objects now provide the ordered_attributes and
1246 specified_attributes attributes. A new module expat.model was added,
1247 which offers a number of additional constants if 1.95.x is used.
1248
1249- xml.dom offers the new functions registerDOMImplementation and
1250 getDOMImplementation.
1251
1252- xml.dom.minidom offers a toprettyxml method. A number of DOM
1253 conformance issues have been resolved. In particular, Element now
1254 has an hasAttributes method, and the handling of namespaces was
1255 improved.
1256
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001257- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1258 getting information about live Python code, and pydoc.py, a module
1259 for interactively converting docstrings to HTML or text.
1260 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001261 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001262 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1263 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001264
Tim Peters1eff7962001-03-01 02:31:33 +00001265- New library module difflib.py, primarily packaging the SequenceMatcher
1266 class at the heart of the popular ndiff.py file-comparison tool.
1267
1268- doctest.py (a framework for verifying Python code examples in docstrings)
1269 is now part of the std library.
1270
Tim Petersd66595f2001-02-04 03:09:53 +00001271Windows changes
1272
Guido van Rossume3955a82001-03-02 14:05:59 +00001273- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1274 small GUI that lets you browse the module docstrings using your
1275 default web browser.
1276
Tim Peters1eff7962001-03-01 02:31:33 +00001277- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1278 Platforms) is implemented. See
1279
1280 http://python.sourceforge.net/peps/pep-0235.html
1281
1282 for full details, especially the "Current Lower-Left Semantics" section.
1283 The new Windows import rules are simpler than before:
1284
1285 A. If the PYTHONCASEOK environment variable exists, same as
1286 before: silently accept the first case-insensitive match of any
1287 kind; raise ImportError if none found.
1288
1289 B. Else search sys.path for the first case-sensitive match; raise
1290 ImportError if none found.
1291
1292 The same rules have been implented on other platforms with case-
1293 insensitive but case-preserving filesystems too (including Cygwin, and
1294 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001295
Tim Peters25a9ce32001-02-19 07:06:36 +00001296- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1297 what it's supposed to do (and does do under NT and 2000) via direct
1298 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001299 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001300 all Win9x systems before.
1301
Tim Peters1eff7962001-03-01 02:31:33 +00001302- Build: Subproject _test (effectively) renamed to _testcapi.
1303
Tim Peters2fe289a2001-03-01 22:19:38 +00001304New platforms
1305
1306- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1307 Thanks to Steven Majewski!
1308
1309- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1310 Tishler!
1311
Guido van Rossum9089b272001-03-02 06:49:50 +00001312- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1313 Schwertberger! See RISCOS/README for more information -- it seems
1314 that because of the bizarre filename conventions on RISCOS, no port
1315 to that platform is easy. Note that the new variable os.endsep is
1316 silently supported in order to make life easier on this platform,
1317 but we don't advertise it because it's not worth for most folks to
1318 care about RISCOS portability.
1319
Tim Peters25a9ce32001-02-19 07:06:36 +00001320
Tim Petersd7b5e882001-01-25 03:36:26 +00001321What's New in Python 2.1 alpha 2?
1322=================================
Tim Peters40ead762001-01-27 05:35:26 +00001323
Tim Petersd7b5e882001-01-25 03:36:26 +00001324Core language, builtins, and interpreter
1325
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001326- Scopes nest. If a name is used in a function or class, but is not
1327 local, the definition in the nearest enclosing function scope will
1328 be used. One consequence of this change is that lambda statements
1329 could reference variables in the namespaces where the lambda is
1330 defined. In some unusual cases, this change will break code.
1331
1332 In all previous version of Python, names were resolved in exactly
1333 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001334 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001335 function A is defined within a function B, the names bound in B are
1336 not visible in A. The new rules make names bound in B visible in A,
1337 unless A contains a name binding that hides the binding in B.
1338
1339 Section 4.1 of the reference manual describes the new scoping rules
1340 in detail. The test script in Lib/test/test_scope.py demonstrates
1341 some of the effects of the change.
1342
1343 The new rules will cause existing code to break if it defines nested
1344 functions where an outer function has local variables with the same
1345 name as globals or builtins used by the inner function. Example:
1346
1347 def munge(str):
1348 def helper(x):
1349 return str(x)
1350 if type(str) != type(''):
1351 str = helper(str)
1352 return str.strip()
1353
1354 Under the old rules, the name str in helper() is bound to the
1355 builtin function str(). Under the new rules, it will be bound to
1356 the argument named str and an error will occur when helper() is
1357 called.
1358
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001359- The compiler will report a SyntaxError if "from ... import *" occurs
1360 in a function or class scope. The language reference has documented
1361 that this case is illegal, but the compiler never checked for it.
1362 The recent introduction of nested scope makes the meaning of this
1363 form of name binding ambiguous. In a future release, the compiler
1364 may allow this form when there is no possibility of ambiguity.
1365
Tim Peters40ead762001-01-27 05:35:26 +00001366- repr(string) is easier to read, now using hex escapes instead of octal,
1367 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1368
1369 >>> "\texample \r\n" + chr(0) + chr(255)
1370 '\texample \r\n\x00\xff' # in 2.1
1371 '\011example \015\012\000\377' # in 2.0
1372
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001373- Functions are now compared and hashed by identity, not by value, since
1374 the func_code attribute is writable.
1375
Fred Drakefb9d7122001-02-01 20:00:40 +00001376- Weak references (PEP 205) have been added. This involves a few
1377 changes in the core, an extension module (_weakref), and a Python
1378 module (weakref). The weakref module is the public interface. It
1379 includes support for "explicit" weak references, proxy objects, and
1380 mappings with weakly held values.
1381
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001382- A 'continue' statement can now appear in a try block within the body
1383 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001384 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001385
Tim Petersd7b5e882001-01-25 03:36:26 +00001386Standard library
1387
Barry Warsaw30dbd142001-01-31 22:14:01 +00001388- mailbox.py now has a new class, PortableUnixMailbox which is
1389 identical to UnixMailbox but uses a more portable scheme for
1390 determining From_ separators. Also, the constructors for all the
1391 classes in this module have a new optional `factory' argument, which
1392 is a callable used when new message classes must be instantiated by
1393 the next() method.
1394
Tim Petersd7b5e882001-01-25 03:36:26 +00001395- random.py is now self-contained, and offers all the functionality of
1396 the now-deprecated whrandom.py. See the docs for details. random.py
1397 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001398 and restoring the internal state of the generator; and jumpahead(n),
1399 for quickly forcing the internal state to be the same as if n calls to
1400 random() had been made. The latter is particularly useful for multi-
1401 threaded programs, creating one instance of the random.Random() class for
1402 each thread, then using .jumpahead() to force each instance to use a
1403 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001404
Tim Peters0de88fc2001-02-01 04:59:18 +00001405- random.py's seed() function is new. For bit-for-bit compatibility with
1406 prior releases, use the whseed function instead. The new seed function
1407 addresses two problems: (1) The old function couldn't produce more than
1408 about 2**24 distinct internal states; the new one about 2**45 (the best
1409 that can be done in the Wichmann-Hill generator). (2) The old function
1410 sometimes produced identical internal states when passed distinct
1411 integers, and there was no simple way to predict when that would happen;
1412 the new one guarantees to produce distinct internal states for all
1413 arguments in [0, 27814431486576L).
1414
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001415- The socket module now supports raw packets on Linux. The socket
1416 family is AF_PACKET.
1417
Tim Peters9ea17ac2001-02-02 05:57:15 +00001418- test_capi.py is a start at running tests of the Python C API. The tests
1419 are implemented by the new Modules/_testmodule.c.
1420
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001421- A new extension module, _symtable, provides provisional access to the
1422 internal symbol table used by the Python compiler. A higher-level
1423 interface will be added on top of _symtable in a future release.
1424
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001425- Removed the obsolete soundex module.
1426
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001427- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1428 the isSameNode method; NamedNodeMap the get method.
1429
1430- xml.sax.expatreader supports the lexical handler property; it
1431 generates comment, startCDATA, and endCDATA events.
1432
Tim Petersee826f82001-01-31 19:39:44 +00001433Windows changes
1434
1435- Build procedure: the zlib project is built in a different way that
1436 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001437 the zlib binary used. See PCbuild\readme.txt for details. Your old
1438 zlib-related directories can be deleted; you'll need to download fresh
1439 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001440
Tim Peters9ea17ac2001-02-02 05:57:15 +00001441- Build: New subproject _test for the benefit of test_capi.py (see above).
1442
Tim Petersb16c56f2001-02-02 21:24:51 +00001443- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1444 interface to some Python compiler internals).
1445
1446- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001447 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001448
Tim Petersa3a3a032000-11-30 05:22:44 +00001449What's New in Python 2.1 alpha 1?
1450=================================
1451
1452Core language, builtins, and interpreter
1453
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001454- There is a new Unicode companion to the PyObject_Str() API
1455 called PyObject_Unicode(). It behaves in the same way as the
1456 former, but assures that the returned value is an Unicode object
1457 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001458
Guido van Rossumf98eda02001-01-17 15:54:45 +00001459- The comparison operators support "rich comparison overloading" (PEP
1460 207). C extension types can provide a rich comparison function in
1461 the new tp_richcompare slot in the type object. The cmp() function
1462 and the C function PyObject_Compare() first try the new rich
1463 comparison operators before trying the old 3-way comparison. There
1464 is also a new C API PyObject_RichCompare() (which also falls back on
1465 the old 3-way comparison, but does not constrain the outcome of the
1466 rich comparison to a Boolean result).
1467
1468 The rich comparison function takes two objects (at least one of
1469 which is guaranteed to have the type that provided the function) and
1470 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1471 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1472 object, which may be NotImplemented (in which case the tp_compare
1473 slot function is used as a fallback, if defined).
1474
1475 Classes can overload individual comparison operators by defining one
1476 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001477 __ge__. There are no explicit "reflected argument" versions of
1478 these; instead, __lt__ and __gt__ are each other's reflection,
1479 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1480 reflection (similar at the C level). No other implications are
1481 made; in particular, Python does not assume that == is the Boolean
1482 inverse of !=, or that < is the Boolean inverse of >=. This makes
1483 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001484
1485 Classes or types that want to implement (in)equality tests but not
1486 the ordering operators (i.e. unordered types) should implement ==
1487 and !=, and raise an error for the ordering operators.
1488
Guido van Rossuma88479f2001-01-18 14:28:08 +00001489 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001490 Boolean; e.g. a matrix type might want to return a matrix of bits
1491 for A < B, giving elementwise comparisons. Such types should ensure
1492 that any interpretation of their value in a Boolean context raises
1493 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1494 at the C level) to always raise an exception.
1495
Guido van Rossuma88479f2001-01-18 14:28:08 +00001496- Complex numbers use rich comparisons to define == and != but raise
1497 an exception for <, <=, > and >=. Unfortunately, this also means
1498 that cmp() of two complex numbers raises an exception when the two
1499 numbers differ. Since it is not mathematically meaningful to compare
1500 complex numbers except for equality, I hope that this doesn't break
1501 too much code.
1502
Tim Peters3389f192001-02-18 08:48:49 +00001503- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001504 not defined by the language, other than that it's arbitrary but
1505 consistent (see the Reference Manual). An implementation detail changed
1506 in 2.1a1 such that None now compares less than any other object. Code
1507 relying on this new behavior (like code that relied on the previous
1508 behavior) does so at its own risk.
1509
Barry Warsaw573b5412001-01-15 20:43:18 +00001510- Functions and methods now support getting and setting arbitrarily
1511 named attributes (PEP 232). Functions have a new __dict__
1512 (a.k.a. func_dict) which hold the function attributes. Methods get
1513 and set attributes on their underlying im_func. It is a TypeError
1514 to set an attribute on a bound method.
1515
Guido van Rossum051e3352001-01-15 19:11:10 +00001516- The xrange() object implementation has been improved so that
1517 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1518 limitation that in this case len(xrange(sys.maxint)) can't be
1519 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1520 work fine as long as the index i doesn't actually reach 2**31.
1521 (Python uses regular ints for sequence and string indices; fixing
1522 that is much more work.)
1523
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001524- Two changes to from...import:
1525
Guido van Rossumba381232001-02-03 15:06:40 +00001526 1) "from M import X" now works even if (after loading module M)
1527 sys.modules['M'] is not a real module; it's basically a getattr()
1528 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001529
1530 2) "from M import *" now looks for M.__all__ to decide which names to
1531 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1532 filters out names starting with '_' as before. Whether or not
1533 __all__ exists, there's no restriction on the type of M.
1534
Guido van Rossumf61f1662001-01-10 20:13:55 +00001535- File objects have a new method, xreadlines(). This is the fastest
1536 way to iterate over all lines in a file:
1537
1538 for line in file.xreadlines():
1539 ...do something to line...
1540
1541 See the xreadlines module (mentioned below) for how to do this for
1542 other file-like objects.
1543
1544- Even if you don't use file.xreadlines(), you may expect a speedup on
1545 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001546 quite a bit in platform-specific ways: on systems (like Linux) that
1547 support flockfile(), getc_unlocked(), and funlockfile(), those are
1548 used by default. On systems (like Windows) without getc_unlocked(),
1549 a complicated (but still thread-safe) method using fgets() is used by
1550 default.
1551
Tim Petersd52269b2001-01-25 06:23:18 +00001552 You can force use of the fgets() method by #define'ing
1553 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001554 getc_unlocked()).
1555
Tim Petersd52269b2001-01-25 06:23:18 +00001556 You can force fgets() not to be used by #define'ing
1557 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001558 test_bufio.py fails -- and let us know if it does!).
1559
1560- In addition, the fileinput module, while still slower than the other
1561 methods on most platforms, has been sped up too, by using
1562 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001563
1564- Support for run-time warnings has been added, including a new
1565 command line option (-W) to specify the disposition of warnings.
1566 See the description of the warnings module below.
1567
1568- Extensive changes have been made to the coercion code. This mostly
1569 affects extension modules (which can now implement mixed-type
1570 numerical operators without having to use coercion), but
1571 occasionally, in boundary cases the coercion semantics have changed
1572 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001573 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001574 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001575 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001576
Guido van Rossumf98eda02001-01-17 15:54:45 +00001577- In connection with the coercion changes, a new built-in singleton
1578 object, NotImplemented is defined. This can be returned for
1579 operations that wish to indicate they are not implemented for a
1580 particular combination of arguments. From C, this is
1581 Py_NotImplemented.
1582
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001583- The interpreter accepts now bytecode files on the command line even
1584 if they do not have a .pyc or .pyo extension. On Linux, after executing
1585
Martin v. Löwise214baa2001-02-04 22:37:56 +00001586import imp,sys,string
1587magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1588reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1589open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001590
1591 any byte code file can be used as an executable (i.e. as an argument
1592 to execve(2)).
1593
Tim Peters9940b802000-12-01 07:59:35 +00001594- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001595 character. In 1.6 and earlier, they never produced a sign,
1596 and raised an error if the value of the long was too large
1597 to fit in a Python int. In 2.0, they produced a sign if and
1598 only if too large to fit in an int. This was inconsistent
1599 across platforms (because the size of an int varies across
1600 platforms), and inconsistent with hex() and oct(). Example:
1601
1602 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001603 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001604 'ffffffbe' # in 2.0 and before, on 32-bit machines
1605 >>> hex(-0x42L)
1606 '-0x42L' # in all versions of Python
1607
Tim Peters9940b802000-12-01 07:59:35 +00001608 The behavior of %d formats for negative Python longs remains
1609 the same as in 2.0 (although in 1.6 and before, they raised
1610 an error if the long didn't fit in a Python int).
1611
1612 %u formats don't make sense for Python longs, but are allowed
1613 and treated the same as %d in 2.1. In 2.0, a negative long
1614 formatted via %u produced a sign if and only if too large to
1615 fit in an int. In 1.6 and earlier, a negative long formatted
1616 via %u raised an error if it was too big to fit in an int.
1617
Guido van Rossum3661d392000-12-12 22:10:31 +00001618- Dictionary objects have an odd new method, popitem(). This removes
1619 an arbitrary item from the dictionary and returns it (in the form of
1620 a (key, value) pair). This can be useful for algorithms that use a
1621 dictionary as a bag of "to do" items and repeatedly need to pick one
1622 item. Such algorithms normally end up running in quadratic time;
1623 using popitem() they can usually be made to run in linear time.
1624
Tim Peters36cdad12000-12-29 02:06:45 +00001625Standard library
1626
Thomas Woutersfe385252001-01-19 23:16:56 +00001627- In the time module, the time argument to the functions strftime,
1628 localtime, gmtime, asctime and ctime is now optional, defaulting to
1629 the current time (in the local timezone).
1630
Guido van Rossumda91f222001-01-15 16:36:08 +00001631- The ftplib module now defaults to passive mode, which is deemed a
1632 more useful default given that clients are often inside firewalls
1633 these days. Note that this could break if ftplib is used to connect
1634 to a *server* that is inside a firewall, from outside; this is
1635 expected to be a very rare situation. To fix that, you can call
1636 ftp.set_pasv(0).
1637
Martin v. Löwis10a27872001-01-13 09:54:41 +00001638- The module site now treats .pth files not only for path configuration,
1639 but also supports extensions to the initialization code: Lines starting
1640 with import are executed.
1641
Guido van Rossumf61f1662001-01-10 20:13:55 +00001642- There's a new module, warnings, which implements a mechanism for
1643 issuing and filtering warnings. There are some new built-in
1644 exceptions that serve as warning categories, and a new command line
1645 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1646 turns warnings into errors). warnings.warn(message[, category])
1647 issues a warning message; this can also be called from C as
1648 PyErr_Warn(category, message).
1649
1650- A new module xreadlines was added. This exports a single factory
1651 function, xreadlines(). The intention is that this code is the
1652 absolutely fastest way to iterate over all lines in an open
1653 file(-like) object:
1654
1655 import xreadlines
1656 for line in xreadlines.xreadlines(file):
1657 ...do something to line...
1658
1659 This is equivalent to the previous the speed record holder using
1660 file.readlines(sizehint). Note that if file is a real file object
1661 (as opposed to a file-like object), this is equivalent:
1662
1663 for line in file.xreadlines():
1664 ...do something to line...
1665
Tim Peters36cdad12000-12-29 02:06:45 +00001666- The bisect module has new functions bisect_left, insort_left,
1667 bisect_right and insort_right. The old names bisect and insort
1668 are now aliases for bisect_right and insort_right. XXX_right
1669 and XXX_left methods differ in what happens when the new element
1670 compares equal to one or more elements already in the list: the
1671 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001672 right. Code that doesn't care where equal elements end up should
1673 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001674
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001675- The new curses.panel module wraps the panel library that forms part
1676 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1677
Guido van Rossumf61f1662001-01-10 20:13:55 +00001678- The SocketServer module now sets the allow_reuse_address flag by
1679 default in the TCPServer class.
1680
1681- A new function, sys._getframe(), returns the stack frame pointer of
1682 the caller. This is intended only as a building block for
1683 higher-level mechanisms such as string interpolation.
1684
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001685- The pyexpat module supports a number of new handlers, which are
1686 available only in expat 1.2. If invocation of a callback fails, it
1687 will report an additional frame in the traceback. Parser objects
1688 participate now in garbage collection. If expat reports an unknown
1689 encoding, pyexpat will try to use a Python codec; that works only
1690 for single-byte charsets. The parser type objects is exposed as
1691 XMLParserObject.
1692
1693- xml.dom now offers standard definitions for symbolic node type and
1694 exception code constants, and a hierarchy of DOM exceptions. minidom
1695 was adjusted to use them.
1696
1697- The conformance of xml.dom.minidom to the DOM specification was
1698 improved. It detects a number of additional error cases; the
1699 previous/next relationship works even when the tree is modified;
1700 Node supports the normalize() method; NamedNodeMap, DocumentType and
1701 DOMImplementation classes were added; Element supports the
1702 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1703 method.
1704
Guido van Rossumf61f1662001-01-10 20:13:55 +00001705Build issues
1706
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001707- For Unix (and Unix-compatible) builds, configuration and building of
1708 extension modules is now greatly automated. Rather than having to
1709 edit the Modules/Setup file to indicate which modules should be
1710 built and where their include files and libraries are, a
1711 distutils-based setup.py script now takes care of building most
1712 extension modules. All extension modules built this way are built
1713 as shared libraries. Only a few modules that must be linked
1714 statically are still listed in the Setup file; you won't need to
1715 edit their configuration.
1716
1717- Python should now build out of the box on Cygwin. If it doesn't,
1718 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001719
1720- Python now always uses its own (renamed) implementation of getopt()
1721 -- there's too much variation among C library getopt()
1722 implementations.
1723
1724- C++ compilers are better supported; the CXX macro is always set to a
1725 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001726
Tim Petersd92dfe02000-12-12 01:18:41 +00001727Windows changes
1728
1729- select module: By default under Windows, a select() call
1730 can specify no more than 64 sockets. Python now boosts
1731 this Microsoft default to 512. If you need even more than
1732 that, see the MS docs (you'll need to #define FD_SETSIZE
1733 and recompile Python from source).
1734
Guido van Rossumf61f1662001-01-10 20:13:55 +00001735- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1736 subdirectory is no more!
1737
Tim Petersa3a3a032000-11-30 05:22:44 +00001738
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001739What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001740=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001741
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001742Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001743changes are in the file HISTORY. If you are making the jump directly
1744from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1745HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001746
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001747Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1748the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1749http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001750
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001751--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001752
1753======================================================================
1754
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001755What's new in 2.0 (since release candidate 1)?
1756==============================================
1757
1758Standard library
1759
1760- The copy_reg module was modified to clarify its intended use: to
1761 register pickle support for extension types, not for classes.
1762 pickle() will raise a TypeError if it is passed a class.
1763
1764- Fixed a bug in gettext's "normalize and expand" code that prevented
1765 it from finding an existing .mo file.
1766
1767- Restored support for HTTP/0.9 servers in httplib.
1768
Tim Peters989b7b92000-10-16 20:24:53 +00001769- The math module was changed to stop raising OverflowError in case of
1770 underflow, and return 0 instead in underflow cases. Whether Python
1771 used to raise OverflowError in case of underflow was platform-
1772 dependent (it did when the platform math library set errno to ERANGE
1773 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001774
1775- Fixed a bug in StringIO that occurred when the file position was not
1776 at the end of the file and write() was called with enough data to
1777 extend past the end of the file.
1778
1779- Fixed a bug that caused Tkinter error messages to get lost on
1780 Windows. The bug was fixed by replacing direct use of
1781 interp->result with Tcl_GetStringResult(interp).
1782
1783- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1784 redirect response.
1785
1786- Several changes were made to distutils: Some debugging code was
1787 removed from util. Fixed the installer used when an external zip
1788 program (like WinZip) is not found; the source code for this
1789 installer is in Misc/distutils. check_lib() was modified to behave
1790 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1791 test for whether installed modules are on sys.path was changed to
1792 use both normcase() and normpath().
1793
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001794- Several minor bugs were fixed in the xml package (the minidom,
1795 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001796
1797- The regression test driver (regrtest.py) behavior when invoked with
1798 -l changed: It now reports a count of objects that are recognized as
1799 garbage but not freed by the garbage collector.
1800
Tim Peters989b7b92000-10-16 20:24:53 +00001801- The regression test for the math module was changed to test
1802 exceptional behavior when the test is run in verbose mode. Python
1803 cannot yet guarantee consistent exception behavior across platforms,
1804 so the exception part of test_math is run only in verbose mode, and
1805 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001806
1807Internals
1808
1809- PyOS_CheckStack() has been disabled on Win64, where it caused
1810 test_sre to fail.
1811
1812Build issues
1813
1814- Changed compiler flags, so that gcc is always invoked with -Wall and
1815 -Wstrict-prototypes. Users compiling Python with GCC should see
1816 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001817 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001818 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001819
Tim Petersa3a3a032000-11-30 05:22:44 +00001820- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001821
1822Tools and other miscellany
1823
1824- The compiler in Tools/compiler was updated to support the new
1825 language features introduced in 2.0: extended print statement, list
1826 comprehensions, and augmented assignments. The new compiler should
1827 also be backwards compatible with Python 1.5.2; the compiler will
1828 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001829 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001830
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001831What's new in 2.0 release candidate 1 (since beta 2)?
1832=====================================================
1833
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001834What is release candidate 1?
1835
1836We believe that release candidate 1 will fix all known bugs that we
1837intend to fix for the 2.0 final release. This release should be a bit
1838more stable than the previous betas. We would like to see even more
1839widespread testing before the final release, so we are producing this
1840release candidate. The final release will be exactly the same unless
1841any show-stopping (or brown bag) bugs are found by testers of the
1842release candidate.
1843
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001844All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001845to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001846
1847Core language, builtins, and interpreter
1848
1849- A bug that caused crashes when __coerce__ was used with augmented
1850 assignment, e.g. +=, was fixed.
1851
1852- Raise ZeroDivisionError when raising zero to a negative number,
1853 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1854 power operator and the result of math.pow(0.0, -2.0) will vary by
1855 platform. On Linux, it raises a ValueError.
1856
1857- A bug in Unicode string interpolation was fixed that occasionally
1858 caused errors with formats including "%%". For example, the
1859 following expression "%% %s" % u"abc" no longer raises a TypeError.
1860
1861- Compilation of deeply nested expressions raises MemoryError instead
1862 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1863
1864- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1865 rendering them useless. They are now written in binary mode again.
1866
1867Standard library
1868
1869- Keyword arguments are now accepted for most pattern and match object
1870 methods in SRE, the standard regular expression engine.
1871
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001872- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001873 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001874
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001875- Several bugs in the Unicode handling and error handling in _tkinter
1876 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001877
1878- Fix memory management errors in Merge() and Tkapp_Call() routines.
1879
1880- Several changes were made to cStringIO to make it compatible with
1881 the file-like object interface and with StringIO. If operations are
1882 performed on a closed object, an exception is raised. The truncate
1883 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001884 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001885
1886- There were many changes made to the linuxaudiodev module and its
1887 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001888 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001889
1890 Note that this module is named poorly, because it should work
1891 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001892 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001893
1894 The module now raises exceptions when errors occur instead of
1895 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1896 audio) and defines a getptr() method that calls the
1897 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1898
1899- The library_version attribute, introduced in an earlier beta, was
1900 removed because it can not be supported with early versions of the C
1901 readline library, which provides no way to determine the version at
1902 compile-time.
1903
1904- The binascii module is now enabled on Win64.
1905
Tim Peters46446d62000-10-09 21:19:31 +00001906- tokenize.py no longer suffers "recursion depth" errors when parsing
1907 programs with very long string literals.
1908
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001909Internals
1910
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001911- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001912 which is called when the interpreter starts up to determine where
1913 the standard library is installed. These vulnerabilities affect all
1914 previous versions of Python and can be exploited by setting very
1915 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1916 setuid Python script, although use of the wrapper in
1917 Misc/setuid-prog.c will eliminate the vulnerability.
1918
1919- Fixed garbage collection bugs in instance creation that were
1920 triggered when errors occurred during initialization. The solution,
1921 applied in cPickle and in PyInstance_New(), is to call
1922 PyObject_GC_Init() after the initialization of the object's
1923 container attributes is complete.
1924
1925- pyexpat adds definitions of PyModule_AddStringConstant and
1926 PyModule_AddObject if the Python version is less than 2.0, which
1927 provides compatibility with PyXML on Python 1.5.2.
1928
1929- If the platform has a bogus definition for LONG_BIT (the number of
1930 bits in a long), an error will be reported at compile time.
1931
1932- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1933 collection crashes and possibly other, unreported crashes.
1934
1935- Fixed a memory leak in _PyUnicode_Fini().
1936
1937Build issues
1938
1939- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001940 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001941 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001942
1943- The mmap.PAGESIZE constant is now initialized using sysconf when
1944 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1945
1946- The md5 file should now compile on all platforms.
1947
1948- The select module now compiles on platforms that do not define
1949 POLLRDNORM and related constants.
1950
1951- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001952 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001953
Jeremy Hylton10921202000-10-09 18:34:12 +00001954- BeOS: A number of changes were made to the build and installation
1955 process. ar-fake now operates on a directory of object files.
1956 dl_export.h is gone, and its macros now appear on the mwcc command
1957 line during build on PPC BeOS.
1958
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001959- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001960 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001961
1962- Cygwin: Support for shared libraries, Tkinter, and sockets.
1963
1964- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1965
1966Tools and other miscellany
1967
1968- Removed debugging prints from main used with freeze.
1969
Tim Peters46446d62000-10-09 21:19:31 +00001970- IDLE auto-indent no longer crashes when it encounters Unicode
1971 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001972
1973What's new in 2.0 beta 2 (since beta 1)?
1974========================================
1975
1976Core language, builtins, and interpreter
1977
Tim Peters482c0212000-09-26 06:33:09 +00001978- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001979 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001980
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001981- Add -h and -V command line options to print the usage message and
1982 Python version number and exit immediately.
1983
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001984- eval() and exec accept Unicode objects as code parameters.
1985
1986- getattr() and setattr() now also accept Unicode objects for the
1987 attribute name, which are converted to strings using the default
1988 encoding before lookup.
1989
1990- Multiplication on string and Unicode now does proper bounds
1991 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1992 string is too long."
1993
1994- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001995 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001996
Jeremy Hylton1b618592000-09-26 05:32:36 +00001997
1998Standard library and extensions
1999
Guido van Rossum5b08f132001-04-16 02:05:23 +00002000- socket module: the OpenSSL code now adds support for RAND_status()
2001 and EGD (Entropy Gathering Device).
2002
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002003- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00002004 argument checking; it still takes no arguments.
2005
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002006- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002007
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002008- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002009
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002010- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002011
2012- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002013 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002014
2015- copy: Copy Unicode objects atomically.
2016
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002017- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002018
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002019- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002020
Fred Drake67233bc2000-09-26 16:40:27 +00002021- dbm: Add get() and setdefault() methods to dbm object. Add constant
2022 `library' to module that names the library used. Added doc strings
2023 and method names to error messages. Uses configure to determine
2024 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2025 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002026
2027- distutils: Update to version 0.9.3.
2028
2029- dl: Add several dl.RTLD_ constants.
2030
2031- fpectl: Now supported on FreeBSD.
2032
2033- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2034 found by the collector will be saved in gc.garbage. This is useful
2035 for debugging a program that creates reference cycles.
2036
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002037- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002038 of HTTP class. Do not close socket on zero-length response. Do not
2039 crash when server sends invalid content-length header.
2040
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002041- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002042
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002043- marshal: When reading a short, sign-extend on platforms where shorts
2044 are bigger than 16 bits. When reading a long, repair the unportable
2045 sign extension that was being done for 64-bit machines. (It assumed
2046 that signed right shift sign-extends.)
2047
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002048- operator: Add contains(), invert(), __invert__() as aliases for
2049 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002050
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002051- os: Add support for popen2() and popen3() on all platforms where
2052 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002053
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002054- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002055 clicking on a file in Explorer (or passing the file name to the
2056 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002057
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002058- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002059 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002060
2061- pickle: Now raises ValueError when an invalid pickle that contains
2062 a non-string repr where a string repr was expected. This behavior
2063 matches cPickle.
2064
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002065- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002066
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002067- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002068
2069- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002070 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002071 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002072
2073- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002074 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002075
2076- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002077 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002078 few cycles during startup since the first call to
2079 setdefaultencoding() will initialize the codec registry and the
2080 encodings package.
2081
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002082- socket: Support for size hint in readlines() method of object returned
2083 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002084
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002085- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002086 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002087 is followed by whitespace.
2088
Tim Petersa3a3a032000-11-30 05:22:44 +00002089- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002090
2091- struct: Check ranges for bytes and shorts.
2092
2093- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002094 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002095
2096- Tkinter: Image objects are now guaranteed to have unique ids. Set
2097 event.delta to zero if Tk version doesn't support mousewheel.
2098 Removed some debugging prints.
2099
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002100- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002101
Fred Drake67233bc2000-09-26 16:40:27 +00002102- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002103 which works around a bug in Norton AntiVirus 2000 that leads directly
2104 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002105
2106- xml: New version detection code allows PyXML to override standard
2107 XML package if PyXML version is greater than 0.6.1.
2108
Fred Drake64bb3802000-09-26 16:21:35 +00002109- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2110 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2111 tree only for nodes which are sufficiently interesting to a specific
2112 application. Does not provide the HTML-specific extensions. Still
2113 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002114
Fred Drake64bb3802000-09-26 16:21:35 +00002115- xml.sax: SAX 2 support for Python, including all the handler
2116 interfaces needed to process XML 1.0 compliant XML. Some
2117 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002118
Fred Drake64bb3802000-09-26 16:21:35 +00002119- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2120 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002121
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002122
Jeremy Hylton1b618592000-09-26 05:32:36 +00002123C API
2124
2125- Add three new convenience functions for module initialization --
2126 PyModule_AddObject(), PyModule_AddIntConstant(), and
2127 PyModule_AddStringConstant().
2128
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002129- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002130 removed and add #error to Python.h if NULL isn't defined after
2131 #include of stdio.h.
2132
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002133- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002134 backwards compatibility (at the source level) with old extensions.
2135
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002136- A wrapper API was added for signal() and sigaction(). Instead of
2137 either function, always use PyOS_getsig() to get a signal handler
2138 and PyOS_setsig() to set one. A new convenience typedef
2139 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002140
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002141- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002142 internal data buffer and size of a string object -- or the default
2143 encoded version of a Unicode object.
2144
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002145- PyString_Size() and PyString_AsString() accept Unicode objects.
2146
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002147- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002148 exists). INT_MAX and LONG_MAX will always be defined, even if
2149 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002150
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002151- PyFloat_FromString takes a second argument, pend, that was
2152 effectively useless. It is now officially useless but preserved for
2153 backwards compatibility. If the pend argument is not NULL, *pend is
2154 set to NULL.
2155
2156- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2157 for the attribute name. See note on getattr() above.
2158
2159- A few bug fixes to argument processing for Unicode.
2160 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2161 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2162 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002163 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002164
2165- Py_BuildValue accepts B format (for bgen-generated code).
2166
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002167
Jeremy Hylton1b618592000-09-26 05:32:36 +00002168Internals
2169
2170- On Unix, fix code for finding Python installation directory so that
2171 it works when argv[0] is a relative path.
2172
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002173- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002174 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002175 rather than by generating a copy of the object.
2176
Tim Peters482c0212000-09-26 06:33:09 +00002177- Several of the internal Unicode tables are much smaller now, and
2178 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002179
Jeremy Hylton97693b02000-09-26 17:42:51 +00002180- In the garbage collector: Fixed bug in collection of tuples. Fixed
2181 bug that caused some instances to be removed from the container set
2182 while they were still live. Fixed parsing in gc.set_debug() for
2183 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002184
2185- Fixed refcount problem in instance deallocation that only occurred
2186 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2187
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002188- On Windows, getpythonregpath is now protected against null data in
2189 registry key.
2190
2191- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002192 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002193
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002194
Jeremy Hylton1b618592000-09-26 05:32:36 +00002195Build and platform-specific issues
2196
2197- Better support of GNU Pth via --with-pth configure option.
2198
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002199- Python/C API now properly exposed to dynamically-loaded extension
2200 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002201
2202- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2203 Don't define MS_SYNC to be zero when it is undefined. Added missing
2204 prototypes in posixmodule.c.
2205
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002206- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002207 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002208
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002209- Fix largefile support on older NetBSD systems and OpenBSD by adding
2210 define for TELL64.
2211
2212
2213Tools and other miscellany
2214
2215- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2216
2217- freeze: The modulefinder now works with 2.0 opcodes.
2218
Tim Petersa3a3a032000-11-30 05:22:44 +00002219- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002220 Move hackery of sys.argv until after the Tk instance has been
2221 created, which allows the application-specific Tkinter
2222 initialization to be executed if present; also pass an explicit
2223 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002224
Jeremy Hylton1b618592000-09-26 05:32:36 +00002225
2226What's new in 2.0 beta 1?
2227=========================
2228
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002229Source Incompatibilities
2230------------------------
2231
2232None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2233such as single-argument append(), connect() and bind(), and changes to
2234str(long) and repr(float).
2235
2236
2237Binary Incompatibilities
2238------------------------
2239
2240- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2241with Python 2.0; these extensions will have to be rebuilt for Python
22422.0.
2243
2244- On Windows, attempting to import a third party extension built for
2245Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2246can do about this. Check your PYTHONPATH environment variable!
2247
2248- Python bytecode files (*.pyc and *.pyo) are not compatible between
2249releases.
2250
2251
2252Overview of Changes Since 1.6
2253-----------------------------
2254
2255There are many new modules (including brand new XML support through
2256the xml package, and i18n support through the gettext module); a list
2257of all new modules is included below. Lots of bugs have been fixed.
2258
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002259The process for making major new changes to the language has changed
2260since Python 1.6. Enhancements must now be documented by a Python
2261Enhancement Proposal (PEP) before they can be accepted.
2262
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002263There are several important syntax enhancements, described in more
2264detail below:
2265
2266 - Augmented assignment, e.g. x += 1
2267
2268 - List comprehensions, e.g. [x**2 for x in range(10)]
2269
2270 - Extended import statement, e.g. import Module as Name
2271
2272 - Extended print statement, e.g. print >> file, "Hello"
2273
2274Other important changes:
2275
2276 - Optional collection of cyclical garbage
2277
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002278Python Enhancement Proposal (PEP)
2279---------------------------------
2280
2281PEP stands for Python Enhancement Proposal. A PEP is a design
2282document providing information to the Python community, or describing
2283a new feature for Python. The PEP should provide a concise technical
2284specification of the feature and a rationale for the feature.
2285
2286We intend PEPs to be the primary mechanisms for proposing new
2287features, for collecting community input on an issue, and for
2288documenting the design decisions that have gone into Python. The PEP
2289author is responsible for building consensus within the community and
2290documenting dissenting opinions.
2291
2292The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002293
2294Augmented Assignment
2295--------------------
2296
2297This must have been the most-requested feature of the past years!
2298Eleven new assignment operators were added:
2299
Guido van Rossume905e952000-09-05 12:42:46 +00002300 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002301
2302For example,
2303
2304 A += B
2305
2306is similar to
2307
2308 A = A + B
2309
2310except that A is evaluated only once (relevant when A is something
2311like dict[index].attr).
2312
2313However, if A is a mutable object, A may be modified in place. Thus,
2314if A is a number or a string, A += B has the same effect as A = A+B
2315(except A is only evaluated once); but if a is a list, A += B has the
2316same effect as A.extend(B)!
2317
2318Classes and built-in object types can override the new operators in
2319order to implement the in-place behavior; the not-in-place behavior is
2320used automatically as a fallback when an object doesn't implement the
2321in-place behavior. For classes, the method name is derived from the
2322method name for the corresponding not-in-place operator by inserting
2323an 'i' in front of the name, e.g. __iadd__ implements in-place
2324__add__.
2325
2326Augmented assignment was implemented by Thomas Wouters.
2327
2328
2329List Comprehensions
2330-------------------
2331
2332This is a flexible new notation for lists whose elements are computed
2333from another list (or lists). The simplest form is:
2334
2335 [<expression> for <variable> in <sequence>]
2336
Guido van Rossum56db0952000-09-06 23:34:25 +00002337For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002338This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002339
2340You can also add a condition:
2341
2342 [<expression> for <variable> in <sequence> if <condition>]
2343
2344For example, [w for w in words if w == w.lower()] would yield the list
2345of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002346than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002347
2348You can also have nested for loops and more than one 'if' clause. For
2349example, here's a function that flattens a sequence of sequences::
2350
2351 def flatten(seq):
2352 return [x for subseq in seq for x in subseq]
2353
2354 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2355
2356This prints
2357
2358 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2359
2360List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002361Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002362
2363
2364Extended Import Statement
2365-------------------------
2366
2367Many people have asked for a way to import a module under a different
2368name. This can be accomplished like this:
2369
2370 import foo
2371 bar = foo
2372 del foo
2373
2374but this common idiom gets old quickly. A simple extension of the
2375import statement now allows this to be written as follows:
2376
2377 import foo as bar
2378
2379There's also a variant for 'from ... import':
2380
2381 from foo import bar as spam
2382
2383This also works with packages; e.g. you can write this:
2384
2385 import test.regrtest as regrtest
2386
2387Note that 'as' is not a new keyword -- it is recognized only in this
2388context (this is only possible because the syntax for the import
2389statement doesn't involve expressions).
2390
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002391Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002392
2393
2394Extended Print Statement
2395------------------------
2396
2397Easily the most controversial new feature, this extension to the print
2398statement adds an option to make the output go to a different file
2399than the default sys.stdout.
2400
2401For example, to write an error message to sys.stderr, you can now
2402write:
2403
2404 print >> sys.stderr, "Error: bad dog!"
2405
2406As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002407evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002408
2409 print >> None, "Hello world"
2410
2411is equivalent to
2412
2413 print "Hello world"
2414
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002415Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002416
2417
2418Optional Collection of Cyclical Garbage
2419---------------------------------------
2420
2421Python is now equipped with a garbage collector that can hunt down
2422cyclical references between Python objects. It's no replacement for
2423reference counting; in fact, it depends on the reference counts being
2424correct, and decides that a set of objects belong to a cycle if all
2425their reference counts can be accounted for from their references to
2426each other. This devious scheme was first proposed by Eric Tiedemann,
2427and brought to implementation by Neil Schemenauer.
2428
2429There's a module "gc" that lets you control some parameters of the
2430garbage collection. There's also an option to the configure script
2431that lets you enable or disable the garbage collection. In 2.0b1,
2432it's on by default, so that we (hopefully) can collect decent user
2433experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002434performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002435off by default in the final 2.0 release.
2436
2437
2438Smaller Changes
2439---------------
2440
2441A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2442map(None, seq1, seq2, ...) when the sequences have the same length;
2443i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2444the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002445zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002446
2447sys.version_info is a tuple (major, minor, micro, level, serial).
2448
2449Dictionaries have an odd new method, setdefault(key, default).
2450dict.setdefault(key, default) returns dict[key] if it exists; if not,
2451it sets dict[key] to default and returns that value. Thus:
2452
2453 dict.setdefault(key, []).append(item)
2454
2455does the same work as this common idiom:
2456
2457 if not dict.has_key(key):
2458 dict[key] = []
2459 dict[key].append(item)
2460
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002461There are two new variants of SyntaxError that are raised for
2462indentation-related errors: IndentationError and TabError.
2463
2464Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2465escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002466
2467The limits on the size of expressions and file in Python source code
2468have been raised from 2**16 to 2**32. Previous versions of Python
2469were limited because the maximum argument size the Python VM accepted
2470was 2**16. This limited the size of object constructor expressions,
2471e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2472limit was raised thanks to a patch by Charles Waldman that effectively
2473fixes the problem. It is now much more likely that you will be
2474limited by available memory than by an arbitrary limit in Python.
2475
2476The interpreter's maximum recursion depth can be modified by Python
2477programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2478limit is the maximum number of recursive calls that can be made by
2479Python code. The limit exists to prevent infinite recursion from
2480overflowing the C stack and causing a core dump. The default value is
24811000. The maximum safe value for a particular platform can be found
2482by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002483
2484New Modules and Packages
2485------------------------
2486
2487atexit - for registering functions to be called when Python exits.
2488
2489imputil - Greg Stein's alternative API for writing custom import
2490hooks.
2491
2492pyexpat - an interface to the Expat XML parser, contributed by Paul
2493Prescod.
2494
2495xml - a new package with XML support code organized (so far) in three
2496subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2497would fill a volume. There's a special feature whereby a
2498user-installed package named _xmlplus overrides the standard
2499xmlpackage; this is intended to give the XML SIG a hook to distribute
2500backwards-compatible updates to the standard xml package.
2501
2502webbrowser - a platform-independent API to launch a web browser.
2503
2504
Guido van Rossume905e952000-09-05 12:42:46 +00002505Changed Modules
2506---------------
2507
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002508array -- new methods for array objects: count, extend, index, pop, and
2509remove
2510
2511binascii -- new functions b2a_hex and a2b_hex that convert between
2512binary data and its hex representation
2513
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002514calendar -- Many new functions that support features including control
2515over which day of the week is the first day, returning strings instead
2516of printing them. Also new symbolic constants for days of week,
2517e.g. MONDAY, ..., SUNDAY.
2518
2519cgi -- FieldStorage objects have a getvalue method that works like a
2520dictionary's get method and returns the value attribute of the object.
2521
2522ConfigParser -- The parser object has new methods has_option,
2523remove_section, remove_option, set, and write. They allow the module
2524to be used for writing config files as well as reading them.
2525
2526ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002527optionally support the RFC 959 REST command.
2528
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002529gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002530
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002531httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2532the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002533
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002534locale -- implement getdefaultlocale for Win32 and Macintosh
2535
2536marshal -- no longer dumps core when marshaling deeply nested or
2537recursive data structures
2538
2539os -- new functions isatty, seteuid, setegid, setreuid, setregid
2540
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002541os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2542support under Unix.
2543
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002544os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002545
2546os.path -- fix semantics of os.path.commonprefix
2547
2548smtplib -- support for sending very long messages
2549
2550socket -- new function getfqdn()
2551
2552readline -- new functions to read, write and truncate history files.
2553The readline section of the library reference manual contains an
2554example.
2555
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002556select -- add interface to poll system call
2557
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002558shutil -- new copyfileobj function
2559
2560SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2561HTTP server.
2562
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002563Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002564
2565urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002566e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002567
2568whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002569
2570
2571Obsolete Modules
2572----------------
2573
2574None. However note that 1.6 made a whole slew of modules obsolete:
2575stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2576poly, zmod, strop, util, whatsound.
2577
2578
2579Changed, New, Obsolete Tools
2580----------------------------
2581
Tim Peters8b092332000-09-05 20:15:25 +00002582None.
Guido van Rossume905e952000-09-05 12:42:46 +00002583
2584
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002585C-level Changes
2586---------------
2587
2588Several cleanup jobs were carried out throughout the source code.
2589
2590All C code was converted to ANSI C; we got rid of all uses of the
2591Py_PROTO() macro, which makes the header files a lot more readable.
2592
2593Most of the portability hacks were moved to a new header file,
2594pyport.h; several other new header files were added and some old
2595header files were removed, in an attempt to create a more rational set
2596of header files. (Few of these ever need to be included explicitly;
2597they are all included by Python.h.)
2598
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002599Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002600and Win64, especially for the new Intel Itanium processor. Mick also
2601added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002602
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002603The C APIs to return an object's size have been update to consistently
2604use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2605previous versions, the abstract interfaces used PyXXX_Length and the
2606concrete interfaces used PyXXX_Size. The old names,
2607e.g. PyObject_Length, are still available for backwards compatibility
2608at the API level, but are deprecated.
2609
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002610The PyOS_CheckStack function has been implemented on Windows by
2611Fredrik Lundh. It prevents Python from failing with a stack overflow
2612on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002613
2614The GC changes resulted in creation of two new slots on object,
2615tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002616the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002617
2618The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002619C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002620
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002621PyErr_Format has been updated to automatically calculate the size of
2622the buffer needed to hold the formatted result string. This change
2623prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002624
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002625New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002626
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002627PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2628that are the same as their non-Ex counterparts except they take an
2629extra flag argument that tells them to close the file when done.
2630
2631XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002632
Tim Peters8b092332000-09-05 20:15:25 +00002633
2634Windows Changes
2635---------------
2636
2637New popen2/popen3/peopen4 in os module (see Changed Modules above).
2638
2639os.popen is much more usable on Windows 95 and 98. See Microsoft
2640Knowledge Base article Q150956. The Win9x workaround described there
2641is implemented by the new w9xpopen.exe helper in the root of your
2642Python installation. Note that Python uses this internally; it is not
2643a standalone program.
2644
2645Administrator privileges are no longer required to install Python
2646on Windows NT or Windows 2000. If you have administrator privileges,
2647Python's registry info will be written under HKEY_LOCAL_MACHINE.
2648Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002649under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002650uses of Python, but will prevent some advanced uses from working
2651(for example, running a Python script as an NT service, or possibly
2652from CGI).
2653
2654[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2655installer; instead, it installs the needed Tcl/Tk files directly in the
2656Python directory. If you already have a Tcl/Tk installation, this
2657wastes some disk space (about 4 Megs) but avoids problems with
2658conflicting Tcl/Tk installations, and makes it much easier for Python
2659to ensure that Tcl/Tk can find all its files.
2660
2661[This was new in 1.6] The Windows installer now installs by default in
2662\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2663
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002664
2665Updates to the changes between 1.5.2 and 1.6
2666--------------------------------------------
2667
2668The 1.6 NEWS file can't be changed after the release is done, so here
2669is some late-breaking news:
2670
2671New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2672and changes to getlocale() and setlocale().
2673
2674The new module is now enabled per default.
2675
2676It is not true that the encodings codecs cannot be used for normal
2677strings: the string.encode() (which is also present on 8-bit strings
2678!) allows using them for 8-bit strings too, e.g. to convert files from
2679cp1252 (Windows) to latin-1 or vice-versa.
2680
2681Japanese codecs are available from Tamito KAJIYAMA:
2682http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2683
2684
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002685======================================================================