blob: 9dca9cebc7f343021557c6895a89718cedd011d8 [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 Rossum50fda3b2001-10-04 19:46:06 +00007- New-style classes are now dynamic by default. Previous, they were
8 static (meaning class attributes could not be assigned to) and
9 dynamic classes had to be requested by adding __dynamic__ = 1 to the
10 body of the class or to the module. Static classes are faster than
11 dynamic classes, but dynamic classes are now at most 50% slower than
12 static classes; previously, they could be up to 10x slower. (This
13 was accomplished by making dynamic classes faster, not by making
14 static classes slower. :-) Note that according to one benchmark,
15 static classes are about the same speed as classic classes.
16
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
Martin v. Löwis16dc7f42001-09-30 20:32:11 +000025- binascii has now two quopri support functions, a2b_qp and b2a_qp.
26
Martin v. Löwis0daad592001-09-30 21:09:59 +000027- readline now supports setting the startup_hook and the pre_event_hook.
28
Martin v. Löwis16628c92001-10-04 22:46:41 +000029- posix supports chroot where available.
30
Tim Petersabf925f2001-09-28 21:53:42 +000031Library
32
Tim Peters7402f792001-10-02 03:53:41 +000033- doctest now excludes functions and classes not defined by the module
34 being tested, thanks to Tim Hochberg.
35
Guido van Rossumc4b09b42001-10-04 10:19:00 +000036- profile now produces correct output in situations where an exception
37 raised in Python is cleared by C code (e.g. hasattr()). This used
38 to cause wrong output, including spurious claims of recursive
39 functions and attribution of time spent to the wrong function.
40
Tim Peters0a1fc4e2001-10-07 03:12:08 +000041 The code and documentation for the derived OldProfile and HotProfile
42 profiling classes was removed. The code hasn't worked for years (if
43 you tried to use them, they raised exceptions). OldProfile
44 intended to reproduce the behavior of the profiler Python used more
45 than 7 years ago, and isn't interesting anymore. HotProfile intended
46 to provide a faster profiler (but producing less information), and
47 that's a worthy goal we intend to meet via a different approach (but
48 without losing information).
49
Tim Peterscce092d2001-10-09 05:31:56 +000050- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +000051 a much better system-specific calibration constant. The constant can
52 now be specified in an instance constructor, or as a Profile class or
53 instance variable, instead of by editing profile.py's source code.
54 Calibration must still be done manually (see the docs for the profile
55 module).
56
57 Note that Profile.calibrate() must be overriden by subclasses.
58 Improving the accuracy required exploiting detailed knowledge of
59 profiler internals; the earlier method abstracted away the details
60 and measured a simplified model instead, but consequently computed
61 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +000062
Martin v. Löwis16dc7f42001-09-30 20:32:11 +000063- quopri's encode and decode methods take an optional header parameter,
64 which indicates whether output is intended for the header 'Q' encoding.
65
Guido van Rossumed554f62001-10-02 23:15:37 +000066Tools/Demos
67
68- Demo/dns was removed. It no longer serves any purpose; a package
69 derived from it is now maintained by Anthony Baxter, see
70 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +000071
72Build
73
74C API
75
Tim Petersd38b1c72001-09-30 05:09:37 +000076- PyLong_AsLongLong() now accepts int (as well as long) arguments.
77 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
78 as long) arguments.
79
Tim Petersabf925f2001-09-28 21:53:42 +000080New platforms
81
82Tests
83
84Windows
85
Tim Peters1ce3cf72001-10-01 17:58:40 +000086- The signal module now supports SIGBREAK on Windows, thanks to Steven
87 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
88 action remains to call Win32 ExitProcess(). This can be changed via
89 signal.signal(). For example:
90
91 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
92 # (SIGINT) behavior.
93 import signal
94 signal.signal(signal.SIGBREAK,
95 signal.default_int_handler)
96
97 try:
98 while 1:
99 pass
100 except KeyboardInterrupt:
101 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
102 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
103 # program without the possibility for any Python-level cleanup).
104 print "Clean exit"
105
Tim Petersabf925f2001-09-28 21:53:42 +0000106
Tim Petersb07352e2001-09-08 01:25:47 +0000107What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000108Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000109===========================
110
Guido van Rossum808eea72001-09-25 04:15:41 +0000111Type/class unification and new-style classes
112
113- pydoc and inspect are now aware of new-style classes;
114 e.g. help(list) at the interactive prompt now shows proper
115 documentation for all operations on list objects.
116
117- Applications using Jim Fulton's ExtensionClass module can now safely
118 be used with Python 2.2. In particular, Zope 2.4.1 now works with
119 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
120 examples also work again. It is hoped that Gtk and Boost also work
121 with 2.2a4 and beyond. (If you can confirm this, please write
122 webmaster@python.org; if there are still problems, please open a bug
123 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000124
Tim Peters66c1a522001-09-24 21:17:50 +0000125- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
126 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
127 in the constructed property object. fget, fset and fdel weren't
128 discoverable from Python in 2.2a3. __doc__ is new, and allows to
129 associate a docstring with a property.
130
Guido van Rossum808eea72001-09-25 04:15:41 +0000131- Comparison overloading is now more completely implemented. For
132 example, a str subclass instance can properly be compared to a str
133 instance, and it can properly overload comparison. Ditto for most
134 other built-in object types.
135
136- The repr() of new-style classes has changed; instead of <type
137 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
138 *except* for built-in types, which are still rendered as <type
139 'Foo'> (to avoid upsetting existing code that might parse or
140 otherwise rely on repr() of certain type objects).
141
142- The repr() of new-style objects is now always <Foo object at XXX>;
143 previously, it was sometimes <Foo instance at XXX>.
144
145- For new-style classes, what was previously called __getattr__ is now
146 called __getattribute__. This method, if defined, is called for
147 *every* attribute access. A new __getattr__ hook mor similar to the
148 one in classic classes is defined which is called only if regular
149 attribute access raises AttributeError; to catch *all* attribute
150 access, you can use __getattribute__ (for new-style classes). If
151 both are defined, __getattribute__ is called first, and if it raises
152 AttributeError, __getattr__ is called.
153
154- The __class__ attribute of new-style objects can be assigned to.
155 The new class must have the same C-level object layout as the old
156 class.
157
158- The builtin file type can be subclassed now. In the usual pattern,
159 "file" is the name of the builtin type, and file() is a new builtin
160 constructor, with the same signature as the builtin open() function.
161 file() is now the preferred way to open a file.
162
163- Previously, __new__ would only see sequential arguments passed to
164 the type in a constructor call; __init__ would see both sequential
165 and keyword arguments. This made no sense whatsoever any more, so
166 now both __new__ and __init__ see all arguments.
167
168- Previously, hash() applied to an instance of a subclass of str or
169 unicode always returned 0. This has been repaired.
170
171- Previously, an operation on an instance of a subclass of an
172 immutable type (int, long, float, complex, tuple, str, unicode),
173 where the subtype didn't override the operation (and so the
174 operation was handled by the builtin type), could return that
175 instance instead a value of the base type. For example, if s was of
176 a str sublass type, s[:] returned s as-is. Now it returns a str
177 with the same value as s.
178
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000179- Provisional support for pickling new-style objects has been added.
180
Guido van Rossum808eea72001-09-25 04:15:41 +0000181Core
182
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000183- file.writelines() now accepts any iterable object producing strings.
184
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000185- PyUnicode_FromEncodedObject() now works very much like
186 PyObject_Str(obj) in that it tries to use __str__/tp_str
187 on the object if the object is not a string or buffer. This
188 makes unicode() behave like str() when applied to non-string/buffer
189 objects.
190
Martin v. Löwis2777c022001-09-19 13:47:32 +0000191- PyFile_WriteObject now passes Unicode object to the file's write
192 method. As a result, all file-like object which may be the target
193 of a print statement must support Unicode objects, i.e. they must
194 at least convert them into ASCII strings.
195
Guido van Rossum624c8af2001-09-18 15:21:04 +0000196- Thread scheduling on Solaris should be improved; it is no longer
197 necessary to insert a small sleep at the start of a thread in order
198 to let other runnable threads be scheduled.
199
Tim Petersb07352e2001-09-08 01:25:47 +0000200Library
201
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000202- StringIO.StringIO instances and cStringIO.StringIO instances support
203 read character buffer compatible objects for their .write() methods.
204 These objects are converted to strings and then handled as such
205 by the instances.
206
Barry Warsaw2f600732001-09-24 04:28:10 +0000207- The "email" package has been added. This is basically a port of the
208 mimelib package <http://sf.net/projects/mimelib> with API changes
209 and some implementations updated to use iterators and generators.
210
Tim Peters8a9c2842001-09-22 21:30:22 +0000211- difflib.ndiff() and difflib.Differ.compare() are generators now. This
212 restores the ability of Tools/scripts/ndiff.py to start producing output
213 before the entire comparison is complete.
214
Barry Warsaw58b072d2001-09-22 04:44:21 +0000215- StringIO.StringIO instances and cStringIO.StringIO instances support
216 iteration just like file objects (i.e. their .readline() method is
217 called for each iteration until it returns an empty string).
218
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000219- The codecs module has grown four new helper APIs to access
220 builtin codecs: getencoder(), getdecoder(), getreader(),
221 getwriter().
222
Guido van Rossum624c8af2001-09-18 15:21:04 +0000223- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
224 simplifies writing XML RPC servers.
225
Barry Warsaw647d5e82001-09-28 17:01:02 +0000226- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000227 after interpretation of symbolic links. On non-Unix systems, this
228 is an alias for os.path.abspath().
229
Tim Peters16a77ad2001-09-08 04:00:12 +0000230- operator.indexOf() (PySequence_Index() in the C API) now works with any
231 iterable object.
232
Guido van Rossum624c8af2001-09-18 15:21:04 +0000233- smtplib now supports various authentication and security features of
234 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000235
Guido van Rossum624c8af2001-09-18 15:21:04 +0000236- hmac: a new module implementing keyed hashing for message
237 authentication.
238
239- mimetypes now recognizes more extensions and file types. At the
240 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000241
Guido van Rossum624c8af2001-09-18 15:21:04 +0000242- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000243 Python 2.2 bytecode generation. It has also been promoted from a
244 Tool to a standard library package. (Tools/compiler still exists as
245 a sample driver.)
246
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000247Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000248
Tim Petersb07352e2001-09-08 01:25:47 +0000249Build
250
Guido van Rossum624c8af2001-09-18 15:21:04 +0000251- Large file support (LFS) is now automatic when the platform supports
252 it; no more manual configuration tweaks are needed. On Linux, at
253 least, it's possible to have a system whose C library supports large
254 files but whose kernel doesn't; in this case, large file support is
255 still enabled but doesn't do you any good unless you upgrade your
256 kernel or share your Python executable with another system whose
257 kernel has large file support.
258
259- The configure script now supplies plausible defaults in a
260 cross-compilation environment. This doesn't mean that the supplied
261 values are always correct, or that cross-compilation now works
262 flawlessly -- but it's a first step (and it shuts up most of
263 autoconf's warnings about AC_TRY_RUN).
264
265- The Unix build is now a bit less chatty, courtesy of the parser
266 generator. The build is completely silent (except for errors) when
267 using "make -s", thanks to a -q option to setup.py.
268
Tim Petersb07352e2001-09-08 01:25:47 +0000269C API
270
Guido van Rossum624c8af2001-09-18 15:21:04 +0000271- The "structmember" API now supports some new flag bits to deny read
272 and/or write access to attributes in restricted execution mode.
273
Tim Petersb07352e2001-09-08 01:25:47 +0000274New platforms
275
Guido van Rossum624c8af2001-09-18 15:21:04 +0000276- Compaq's iPAQ handheld, running the "familiar" Linux distribution
277 (http://familiar.handhelds.org).
278
Tim Petersb07352e2001-09-08 01:25:47 +0000279Tests
280
Tim Peters8a9c2842001-09-22 21:30:22 +0000281- The "classic" standard tests, which work by comparing stdout to
282 an expected-output file under Lib/test/output/, no longer stop at
283 the first mismatch. Instead the test is run to completion, and a
284 variant of ndiff-style comparison is used to report all differences.
285 This is much easier to understand than the previous style of reporting.
286
287- The unittest-based standard tests now use regrtest's test_main()
288 convention, instead of running as a side-effect of merely being
289 imported. This allows these tests to be run in more natural and
290 flexible ways as unittests, outside the regrtest framework.
291
292- regrtest.py is much better integrated with unittest and doctest now,
293 especially in regard to reporting errors.
294
Tim Petersb07352e2001-09-08 01:25:47 +0000295Windows
296
Guido van Rossum624c8af2001-09-18 15:21:04 +0000297- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000298 that support it (NTFS under Windows 2000). See "What's New in
299 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000300
Tim Petersb07352e2001-09-08 01:25:47 +0000301
Tim Petersedc99312001-08-22 21:36:50 +0000302What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000303Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000304===========================
305
306Core
307
Tim Peters9fffa3e2001-09-04 05:14:19 +0000308- Conversion of long to float now raises OverflowError if the long is too
309 big to represent as a C double.
310
Tim Peters32f453e2001-09-03 08:35:41 +0000311- The 3-argument builtin pow() no longer allows a third non-None argument
312 if either of the first two arguments is a float, or if both are of
313 integer types and the second argument is negative (in which latter case
314 the arguments are converted to float, so this is really the same
315 restriction).
316
Tim Peters5d2b77c2001-09-03 05:47:38 +0000317- The builtin dir() now returns more information, and sometimes much
318 more, generally naming all attributes of an object, and all attributes
319 reachable from the object via its class, and from its class's base
320 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
321 an empty list. In 2.2a3,
322
323 >>> dir([])
324 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
325 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
326 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
327 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
328 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
329 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
330 'reverse', 'sort']
331
332 dir(module) continues to return only the module's attributes, though.
333
Tim Petersbdee63f2001-09-02 03:40:59 +0000334- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000335 than raising OverflowError. This is a partial implementation of PEP
336 237. You can use -Wdefault::OverflowWarning to enable a warning for
337 this situation, and -Werror::OverflowWarning to revert to the old
338 OverflowError exception.
339
Guido van Rossum61c345f2001-09-04 03:26:15 +0000340- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000341 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000342 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
343 -Qold, meaning the / operator has its classic meaning and no
344 warnings are issued. Using -Qwarn issues a run-time warning about
345 all uses of classic division for int and long arguments; -Qwarnall
346 also warns about classic division for float and complex arguments
347 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
348 new division by default, but only in the __main__ module. You can
349 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
350 __main__ module new division, and warns about classic division
351 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000352
Tim Petersbdee63f2001-09-02 03:40:59 +0000353- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000354 long, float, str, unicode, and tuple. (The types complex, list and
355 dictionary can also be subclassed; this was introduced earlier.)
356 Note that restrictions apply when subclassing immutable built-in
357 types: you can only affect the value of the instance by overloading
358 __new__. You can add mutable attributes, and the subclass instances
359 will have a __dict__ attribute, but you cannot change the "value"
360 (as implemented by the base class) of an immutable subclass instance
361 once it is created.
362
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000363- The dictionary constructor now takes an optional argument, a
364 mapping-like object, and initializes the dictionary from its
365 (key, value) pairs.
366
Tim Petersbdee63f2001-09-02 03:40:59 +0000367- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000368 "cooperative super calls" in a multiple inheritance setting. For an
369 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
370
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000371- A new built-in type, property, has been added. This enables the
372 creation of "properties". These are attributes implemented by
373 getter and setter functions (or only one of these for read-only or
374 write-only attributes), without the need to override __getattr__.
375 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000376
Tim Petersbdee63f2001-09-02 03:40:59 +0000377- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000378 liberalized, to allow leading zeroes. Examples of literals now
379 legal that were SyntaxErrors before:
380
381 00.0 0e3 0100j 07.5 00000000000000000008.
382
Tim Petersbdee63f2001-09-02 03:40:59 +0000383- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000384 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
385
Tim Petersedc99312001-08-22 21:36:50 +0000386Library
387
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000388- telnetlib includes symbolic names for the options, and support for
389 setting an option negotiation callback.
390
Tim Petersa40c7932001-09-05 22:36:56 +0000391- The new C standard no longer requires that math libraries set errno to
392 ERANGE on overflow. For platform libraries that exploit this new
393 freedom, Python's overflow-checking was wholly broken. A new overflow-
394 checking scheme attempts to repair that, but may not be reliable on all
395 platforms (C doesn't seem to provide anything both useful and portable
396 in this area anymore).
397
Martin v. Löwis44f86962001-09-05 13:44:54 +0000398- Asynchronous timeout actions are available through the new class
399 threading.Timer.
400
Tim Peters78526162001-09-05 00:53:45 +0000401- math.log and math.log10 now return sensible results for even huge
402 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
403
Tim Petersbdee63f2001-09-02 03:40:59 +0000404- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000405 currently held. See the docs for the imp module.
406
Tim Petersbdee63f2001-09-02 03:40:59 +0000407- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000408 dumps containing ints written on platforms where Python ints are 8 bytes.
409 When read on a box where Python ints are 4 bytes, such values are
410 converted to Python longs.
411
Tim Petersbdee63f2001-09-02 03:40:59 +0000412- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000413 code objects is no longer allowed. This plugs a security hole.
414
Steve Purcell6091cd62001-09-06 16:05:17 +0000415- unittest.TestResult instances no longer store references to tracebacks
416 generated by test failures. This prevents unexpected dangling references
417 to objects that should be garbage collected between tests.
418
Tim Petersedc99312001-08-22 21:36:50 +0000419Tools
420
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000421- Tools/scripts/fixdiv.py has been added which can be used to fix
422 division operators as per PEP 238.
423
Tim Petersedc99312001-08-22 21:36:50 +0000424Build
425
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000426- If you are an adventurous person using Mac OS X you may want to look at
427 Mac/OSX. There is a Makefile there that will build Python as a real Mac
428 application, which can be used for experimenting with Carbon or Cocoa.
429 Discussion of this on pythonmac-sig, please.
430
Tim Peters7eea37e2001-09-04 22:08:56 +0000431C API
432
433- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000434
Tim Peters9fffa3e2001-09-04 05:14:19 +0000435- Note that PyLong_AsDouble can fail! This has always been true, but no
436 callers checked for it. It's more likely to fail now, because overflow
437 errors are properly detected now. The proper way to check:
438
439 double x = PyLong_AsDouble(some_long_object);
440 if (x == -1.0 && PyErr_Occurred()) {
441 /* The conversion failed. */
442 }
443
Tim Petersbdee63f2001-09-02 03:40:59 +0000444- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000445 compile but will not participate in GC. To upgrade an extension
446 module:
447
448 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000449
Neil Schemenauer4042c692001-08-30 15:38:01 +0000450 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
451 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000452
Neil Schemenauer4042c692001-08-30 15:38:01 +0000453 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
454 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000455
Neil Schemenauer4042c692001-08-30 15:38:01 +0000456 - remove PyGC_HEAD_SIZE from object size calculations
457
458 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
459
Tim Petersbdee63f2001-09-02 03:40:59 +0000460- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000461 These can be used safely to construct string objects from a
462 sprintf-style format string (similar to the format string supported
463 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000464
Tim Petersedc99312001-08-22 21:36:50 +0000465New platforms
466
Tim Petersb7da0902001-09-02 23:01:43 +0000467- Stephen Hansen contributed patches sufficient to get a clean compile
468 under Borland C (Windows), but he reports problems running it and ran
469 out of time to complete the port. Volunteers? Expect a MemoryError
470 when importing the types module; this is probably shallow, and
471 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000472
Tim Petersedc99312001-08-22 21:36:50 +0000473Tests
474
475Windows
476
Tim Peters6e13a562001-09-06 00:32:15 +0000477- Large file support is now enabled on Win32 platforms as well as on
478 Win64. This means that, for example, you can use f.tell() and f.seek()
479 to manipulate files larger than 2 gigabytes (provided you have enough
480 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000481 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
482 filesize limit, and large file support makes no difference there.
483 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
484 NTFS has no practical limit on file size, and files of any size can be
485 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000486
Tim Petersbdee63f2001-09-02 03:40:59 +0000487- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000488 points to command.com (patch from Brian Quinlan).
489
Tim Petersedc99312001-08-22 21:36:50 +0000490
Tim Peters20f51a72001-07-21 02:31:40 +0000491What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000492Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000493===========================
494
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000495Build
496
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000497- Tim Peters developed a brand new Windows installer using Wise 8.1,
498 generously donated to us by Wise Solutions.
499
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000500- configure supports a new option --enable-unicode, with the values
501 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
502 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000503
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000504- A new configure option --enable-framework builds a Mac OS X framework,
505 which "make frameworkinstall" will install. This provides a starting
506 point for more mac-like functionality, join pythonmac-sig@python.org
507 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000508
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000509- The NeXT platform is no longer supported.
510
511- The `new' module is now statically linked.
512
Tim Peters0afb6092001-08-15 06:06:44 +0000513Tools
514
515- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000516 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000517 the module docstring for details.
518
Tim Peters20f51a72001-07-21 02:31:40 +0000519Tests
520
Tim Peters5e824c32001-08-12 22:25:01 +0000521- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000522 platforms, allowing to give clearer test result output. regrtest
523 also has optional --use/-u switch to run normally disabled tests
524 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000525
Tim Peters20f51a72001-07-21 02:31:40 +0000526- Several new tests in the standard test suite, with special thanks to
527 Nick Mathewson.
528
529Core
530
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000531- The floor division operator // has been added as outlined in PEP
532 238. The / operator still provides classic division (and will until
533 Python 3.0) unless "from __future__ import division" is included, in
534 which case the / operator will provide true division. The operator
535 module provides truediv() and floordiv() functions. Augmented
536 assignment variants are included, as are the equivalent overloadable
537 methods and C API methods. See the PEP for a full discussion:
538 <http://python.sf.net/peps/pep-0238.html>
539
Tim Peters6cd6a822001-08-17 22:11:27 +0000540- Future statements are now effective in simulated interactive shells
541 (like IDLE). This should "just work" by magic, but read Michael
542 Hudson's "Future statements in simulated shells" PEP 264 for full
543 details: <http://python.sf.net/peps/pep-0264.html>.
544
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000545- The type/class unification (PEP 252-253) was integrated into the
546 trunk and is not so tentative any more (the exact specification of
547 some features is still tentative). A lot of work has done on fixing
548 bugs and adding robustness and features (performance still has to
549 come a long way).
550
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000551- Warnings about a mismatch in the Python API during extension import
552 now use the Python warning framework (which makes it possible to
553 write filters for these warnings).
554
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000555- A function's __dict__ (aka func_dict) will now always be a
556 dictionary. It used to be possible to delete it or set it to None,
557 but now both actions raise TypeErrors. It is still legal to set it
558 to a dictionary object. Getting func.__dict__ before any attributes
559 have been assigned now returns an empty dictionary instead of None.
560
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000561- A new command line option, -E, was added which disables the use of
562 all environment variables, or at least those that are specifically
563 significant to Python. Usually those have a name starting with
564 "PYTHON". This was used to fix a problem where the tests fail if
565 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
566 older distribution.
567
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000568Library
569
Tim Peters5e824c32001-08-12 22:25:01 +0000570- New class Differ and new functions ndiff() and restore() in difflib.py.
571 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000572 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000573
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000574- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
575 value using the minimal quoting required for the value; more
576 reliable than using xml.sax.saxutils.escape() for attribute values.
577
578- Readline completion support for cmd.Cmd was added.
579
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000580- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
581
582- Added function threading.BoundedSemaphore()
583
584- Added Ka-Ping Yee's cgitb.py module.
585
586- The `new' module now exposes the CO_xxx flags.
587
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000588New platforms
589
590C API
591
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000592- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
593 which provide a cross-platform implementations for the
594 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
595 the standard sprintf() and vsprintf() C lib APIs, these versions
596 apply bounds checking on the used buffer which enhances protection
597 against buffer overruns.
598
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000599- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000600 and extensions using different Unicode widths is rendered next to
601 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000602 will result in an ImportError. Unicode extensions writers must make
603 sure to check the Unicode width compatibility in their extensions by
604 using at least one of the mangled Unicode APIs in the extension.
605
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000606- Two new flags METH_NOARGS and METH_O are available in method definition
607 tables to simplify implementation of methods with no arguments and a
608 single untyped argument. Calling such methods is more efficient than
609 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
610 deprecated.
611
Tim Petersc1731372001-08-04 08:12:36 +0000612Windows
613
614- "import module" now compiles module.pyw if it exists and nothing else
615 relevant is found.
616
Tim Peters20f51a72001-07-21 02:31:40 +0000617
Guido van Rossum55a78992001-07-17 17:22:32 +0000618What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +0000619===========================
620
621Core
Tim Petersa814db52001-05-14 07:05:58 +0000622
Tim Peters6d6c1a32001-08-02 04:15:00 +0000623- TENTATIVELY, a large amount of code implementing much of what's
624 described in PEP 252 (Making Types Look More Like Classes) and PEP
625 253 (Subtyping Built-in Types) was added. This will be released
626 with Python 2.2a1. Documentation will be provided separately
627 through http://www.python.org/2.2/. The purpose of releasing this
628 with Python 2.2a1 is to test backwards compatibility. It is
629 possible, though not likely, that a decision is made not to release
630 this code as part of 2.2 final, if any serious backwards
631 incompapatibilities are found during alpha testing that cannot be
632 repaired.
633
Guido van Rossum55a78992001-07-17 17:22:32 +0000634- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000635 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000636 more 'yield' statements. See PEP 255. Since this adds a new
637 keyword to the language, this feature must be enabled by including a
638 future statement: "from __future__ import generators" (see PEP 236).
639 Generators will become a standard feature in a future release
640 (probably 2.3). Without this future statement, 'yield' remains an
641 ordinary identifier, but a warning is issued each time it is used.
642 (These warnings currently don't conform to the warnings framework of
643 PEP 230; we intend to fix this in 2.2a2.)
644
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000645- The UTF-16 codec was modified to be more RFC compliant. It will now
646 only remove BOM characters at the start of the string and then
647 only if running in native mode (UTF-16-LE and -BE won't remove a
648 leading BMO character).
649
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000650- Strings now have a new method .decode() to complement the already
651 existing .encode() method. These two methods provide direct access
652 to the corresponding decoders and encoders of the registered codecs.
653
654 To enhance the usability of the .encode() method, the special
655 casing of Unicode object return values was dropped (Unicode objects
656 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000657
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000658 Both methods will now return whatever the codec in charge of the
659 requested encoding returns as object, e.g. Unicode codecs will
660 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
661 will return u"äöü"). This enables codec writer to create codecs
662 for various simple to use conversions.
663
664 New codecs were added to demonstrate these new features (the .encode()
665 and .decode() columns indicate the type of the returned objects):
666
667 Name | .encode() | .decode() | Description
668 ----------------------------------------------------------------------
669 uu | string | string | UU codec (e.g. for email)
670 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000671 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000672 zlib | string | string | zlib compression
673 hex | string | string | 2-byte hex codec
674 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
675
Mark Hammond2a0af792001-05-14 03:09:36 +0000676- Some operating systems now support the concept of a default Unicode
677 encoding for file system operations. Notably, Windows supports 'mbcs'
678 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000679 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000680 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000681
682 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000683 functions that return filenames (such as os.listdir()) to return Python
684 string objects pre-encoded using the default file system encoding for
685 the platform. As this encoding is likely to be different from Python's
686 default encoding, converting this name to a Unicode object before passing
687 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000688 would attempt to use its default encoding (generally ASCII) rather than
689 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000690
Tim Petersa814db52001-05-14 07:05:58 +0000691 In general, this change simply removes surprises when working with
692 Unicode and the file system, making these operations work as you expect,
693 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000694 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000695
Tim Peters61dff2b2001-05-08 15:43:37 +0000696- Float (and complex) literals in source code were evaluated to full
697 precision only when running from a .py file; the same code loaded from a
698 .pyc (or .pyo) file could suffer numeric differences starting at about the
699 12th significant decimal digit. For example, on a machine with IEEE-754
700 floating arithmetic,
701
702 x = 9007199254740992.0
703 print long(x)
704
705 printed 9007199254740992 if run directly from .py, but 9007199254740000
706 if from a compiled (.pyc or .pyo) file. This was due to marshal using
707 str(float) instead of repr(float) when building code objects. marshal
708 now uses repr(float) instead, which should reproduce floats to full
709 machine precision (assuming the platform C float<->string I/O conversion
710 functions are of good quality).
711
712 This may cause floating-point results to change in some cases, and
713 usually for the better, but may also cause numerically unstable
714 algorithms to break.
715
Tim Peters2f228e72001-05-13 00:19:31 +0000716- The implementation of dicts suffers fewer collisions, which has speed
717 benefits. However, the order in which dict entries appear in dict.keys(),
718 dict.values() and dict.items() may differ from previous releases for a
719 given dict. Nothing is defined about this order, so no program should
720 rely on it. Nevertheless, it's easy to write test cases that rely on the
721 order by accident, typically because of printing the str() or repr() of a
722 dict to an "expected results" file. See Lib/test/test_support.py's new
723 sortdict(dict) function for a simple way to display a dict in sorted
724 order.
725
Tim Peters7a3bfc32001-06-12 01:22:22 +0000726- Many other small changes to dicts were made, resulting in faster
727 operation along the most common code paths.
728
Guido van Rossum10315822001-05-01 20:54:30 +0000729- Dictionary objects now support the "in" operator: "x in dict" means
730 the same as dict.has_key(x).
731
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000732- The update() method of dictionaries now accepts generic mapping
733 objects. Specifically the argument object must support the .keys()
734 and __getitem__() methods. This allows you to say, for example,
735 {}.update(UserDict())
736
Guido van Rossum10315822001-05-01 20:54:30 +0000737- Iterators were added; this is a generalized way of providing values
738 to a for loop. See PEP 234. There's a new built-in function iter()
739 to return an iterator. There's a new protocol to get the next value
740 from an iterator using the next() method (in Python) or the
741 tp_iternext slot (in C). There's a new protocol to get iterators
742 using the __iter__() method (in Python) or the tp_iter slot (in C).
743 Iterating (i.e. a for loop) over a dictionary generates its keys.
744 Iterating over a file generates its lines.
745
Tim Petersf553f892001-05-01 20:45:31 +0000746- The following functions were generalized to work nicely with iterator
747 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000748 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000749 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
750 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000751 join() method of strings
752 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000753 'x in y' and 'x not in y' (PySequence_Contains() in C API)
754 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000755 right-hand side of assignment statements with multiple targets, such as
756 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000757
Tim Petersd85e1022001-05-11 21:51:48 +0000758- Accessing module attributes is significantly faster (for example,
759 random.random or os.path or yourPythonModule.yourAttribute).
760
Tim Peterse63415e2001-05-08 04:38:29 +0000761- Comparing dictionary objects via == and != is faster, and now works even
762 if the keys and values don't support comparisons other than ==.
763
Tim Peters95bf9392001-05-10 08:32:44 +0000764- Comparing dictionaries in ways other than == and != is slower: there were
765 insecurities in the dict comparison implementation that could cause Python
766 to crash if the element comparison routines for the dict keys and/or
767 values mutated the dicts. Making the code bulletproof slowed it down.
768
Tim Peterseb28ef22001-06-02 05:27:19 +0000769- Collisions in dicts are resolved via a new approach, which can help
770 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000771 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000772 faster now. Thanks to Christian Tismer for pointing out the cause and
773 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000774
Tim Peters52e155e2001-06-16 05:42:57 +0000775- repr() is much faster for large containers (dict, list, tuple).
776
777
Tim Petersa814db52001-05-14 07:05:58 +0000778Library
779
Fred Drake960fdf92001-07-20 18:38:26 +0000780- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
781 were added to the string module. These a locale-indenpendent
782 constants, unlike letters, lowercase, and uppercase. These are now
783 use in appropriate locations in the standard library.
784
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000785- The flags used in dlopen calls can now be configured using
786 sys.setdlopenflags and queried using sys.getdlopenflags.
787
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000788- Fredrik Lundh's xmlrpclib is now a standard library module. This
789 provides full client-side XML-RPC support. In addition,
790 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
791 one asyncore-based). Thanks to Eric Raymond for the documentation.
792
Guido van Rossum643d3912001-07-05 14:46:25 +0000793- The xrange() object is simplified: it no longer supports slicing,
794 repetition, comparisons, efficient 'in' checking, the tolist()
795 method, or the start, stop and step attributes. See PEP 260.
796
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000797- A new function fnmatch.filter to filter lists of file names was added.
798
Barry Warsawffd674d2001-05-22 16:00:10 +0000799- calendar.py uses month and day names based on the current locale.
800
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000801- strop is now *really* obsolete (this was announced before with 1.6),
802 and issues DeprecationWarning when used (except for the four items
803 that are still imported into string.py).
804
Tim Petersa814db52001-05-14 07:05:58 +0000805- Cookie.py now sorts key+value pairs by key in output strings.
806
807- pprint.isrecursive(object) didn't correctly identify recursive objects.
808 Now it does.
809
Tim Peters95b3f782001-05-14 18:39:41 +0000810- pprint functions now much faster for large containers (tuple, list, dict).
811
Tim Peters7b9542a2001-06-10 23:40:19 +0000812- New 'q' and 'Q' format codes in the struct module, corresponding to C
813 types "long long" and "unsigned long long" (on Windows, __int64). In
814 native mode, these can be used only when the platform C compiler supports
815 these types (when HAVE_LONG_LONG is #define'd by the Python config
816 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000817 In standard mode, 'q' and 'Q' are supported on all platforms, and are
818 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000819
Guido van Rossum83213cc2001-06-12 16:48:52 +0000820- The site module installs a new built-in function 'help' that invokes
821 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
822 it displays a message reminding the user to use 'help()' or
823 'help(object)'.
824
Tim Petersa814db52001-05-14 07:05:58 +0000825Tests
826
827- New test_mutants.py runs dict comparisons where the key and value
828 comparison operators mutute the dicts randomly during comparison. This
829 rapidly causes Python to crash under earlier releases (not for the faint
830 of heart: it can also cause Win9x to freeze or reboot!).
831
832- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000833 pprint.isreadable() return sensible results. Also verifies that simple
834 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000835
Tim Peters4324aa32001-05-28 22:30:08 +0000836C API
837
838- Removed the unused last_is_sticky argument from the internal
839 _PyTuple_Resize(). If this affects you, you were cheating.
840
841
Guido van Rossum55a78992001-07-17 17:22:32 +0000842======================================================================
843
844
Guido van Rossumffe13be2001-04-16 18:46:45 +0000845What's New in Python 2.1 (final)?
846=================================
847
848We only changed a few things since the last release candidate, all in
849Python library code:
850
851- A bug in the locale module was fixed that affected locales which
852 define no grouping for numeric formatting.
853
854- A few bugs in the weakref module's implementations of weak
855 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
856 and the test suite was updated to check for these bugs.
857
858- An old bug in the os.path.walk() function (introduced in Python
859 2.0!) was fixed: a non-existent file would cause an exception
860 instead of being ignored.
861
862- Fixed a few bugs in the new symtable module found by Neil Norwitz's
863 PyChecker.
864
865
Guido van Rossum5b08f132001-04-16 02:05:23 +0000866What's New in Python 2.1c2?
867===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000868
Guido van Rossum5b08f132001-04-16 02:05:23 +0000869A flurry of small changes, and one showstopper fixed in the nick of
870time made it necessary to release another release candidate. The list
871here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000872
Guido van Rossum5b08f132001-04-16 02:05:23 +0000873Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000874
Guido van Rossum5b08f132001-04-16 02:05:23 +0000875- Tim discovered a nasty bug in the dictionary code, caused by
876 PyDict_Next() calling dict_resize(), and the GC code's use of
877 PyDict_Next() violating an assumption in dict_items(). This was
878 fixed with considerable amounts of band-aid, but the net effect is a
879 saner and more robust implementation.
880
881- Made a bunch of symbols static that were accidentally global.
882
883Build and Ports
884
885- The setup.py script didn't check for a new enough version of zlib
886 (1.1.3 is needed). Now it does.
887
888- Changed "make clean" target to also remove shared libraries.
889
890- Added a more general warning about the SGI Irix optimizer to README.
891
892Library
893
894- Fix a bug in urllib.basejoin("http://host", "../file.html") which
895 omitted the slash between host and file.html.
896
897- The mailbox module's _Mailbox class contained a completely broken
898 and undocumented seek() method. Ripped it out.
899
900- Fixed a bunch of typos in various library modules (urllib2, smtpd,
901 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
902
903- Fixed a few last-minute bugs in unittest.
904
905Extensions
906
907- Reverted the patch to the OpenSSL code in socketmodule.c to support
908 RAND_status() and the EGD, and the subsequent patch that tried to
909 fix it for pre-0.9.5 versions; the problem with the patch is that on
910 some systems it issues a warning whenever socket is imported, and
911 that's unacceptable.
912
913Tests
914
915- Fixed the pickle tests to work with "import test.test_pickle".
916
917- Tweaked test_locale.py to actually run the test Windows.
918
919- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
920 not "wb" (which is not a valid mode at all).
921
922- Fix pstats browser crashes. Import readline if it exists to make
923 the user interface nicer.
924
925- Add "import thread" to the top of test modules that import the
926 threading module (test_asynchat and test_threadedtempfile). This
927 prevents test failures caused by a broken threading module resulting
928 from a previously caught failed import.
929
930- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
931 needed on some platforms (e.g. Solaris 8) when the tests are run
932 twice in succession.
933
934- Skip rather than fail test_sunaudiodev if no audio device is found.
935
936
937What's New in Python 2.1c1?
938===========================
939
940This list was significantly updated when 2.1c2 was released; the 2.1c1
941release didn't mention most changes that were actually part of 2.1c1:
942
943Legal
944
945- Copyright was assigned to the Python Software Foundation (PSF) and a
946 PSF license (very similar to the CNRI license) was added.
947
948- The CNRI copyright notice was updated to include 2001.
949
950Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000951
Guido van Rossumc9932722001-04-12 02:31:27 +0000952- After a public outcry, assignment to __debug__ is no longer illegal;
953 instead, a warning is issued. It will become illegal in 2.2.
954
Guido van Rossum5b08f132001-04-16 02:05:23 +0000955- Fixed a core dump with "%#x" % 0, and changed the semantics so that
956 "%#x" now always prepends "0x", even if the value is zero.
957
958- Fixed some nits in the bytecode compiler.
959
960- Fixed core dumps when calling certain kinds of non-functions.
961
962- Fixed various core dumps caused by reference count bugs.
963
964Build and Ports
965
966- Use INSTALL_SCRIPT to install script files.
967
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000968- New port: SCO Unixware 7, by Billy G. Allie.
969
Guido van Rossum5b08f132001-04-16 02:05:23 +0000970- Updated RISCOS port.
971
972- Updated BeOS port and notes.
973
974- Various other porting problems resolved.
975
976Library
977
978- The TERMIOS and SOCKET modules are now truly obsolete and
979 unnecessary. Their symbols are incorporated in the termios and
980 socket modules.
981
982- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
983 better tests for pickling.
984
985- threading: make Condition.wait() robust against KeyboardInterrupt.
986
987- zipfile: add support to zipfile to support opening an archive
988 represented by an open file rather than a file name. Fix bug where
989 the archive was not properly closed. Fixed a bug in this bugfix
990 where flush() was called for a read-only file.
991
992- imputil: added an uninstall() method to the ImportManager.
993
994- Canvas: fixed bugs in lower() and tkraise() methods.
995
996- SocketServer: API change (added overridable close_request() method)
997 so that the TCP server can explicitly close the request.
998
999- pstats: Eric Raymond added a simple interactive statistics browser,
1000 invoked when the module is run as a script.
1001
1002- locale: fixed a problem in format().
1003
1004- webbrowser: made it work when the BROWSER environment variable has a
1005 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1006 KDE 2. Fixed some other nits.
1007
1008- unittest: changes to allow using a different exception than
1009 AssertionError, and added a few more function aliases. Some other
1010 small changes.
1011
1012- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1013
1014- asynchat: fixed a critical bug in asynchat that slipped through the
1015 2.1b2 release. Fixed another rare bug.
1016
1017- Fix some unqualified except: clauses (always a bad code example).
1018
1019XML
1020
1021- pyexpat: new API get_version_string().
1022
1023- Fixed some minidom bugs.
1024
1025Extensions
1026
1027- Fixed a core dump in _weakref. Removed the weakref.mapping()
1028 function (it adds nothing to the API).
1029
1030- Rationalized the use of header files in the readline module, to make
1031 it compile (albeit with some warnings) with the very recent readline
1032 4.2, without breaking for earlier versions.
1033
1034- Hopefully fixed a buffering problem in linuxaudiodev.
1035
1036- Attempted a fix to make the OpenSSL support in the socket module
1037 work again with pre-0.9.5 versions of OpenSSL.
1038
1039Tests
1040
1041- Added a test case for asynchat and asyncore.
1042
1043- Removed coupling between tests where one test failing could break
1044 another.
1045
1046Tools
1047
1048- Ping added an interactive help browser to pydoc, fixed some nits
1049 in the rest of the pydoc code, and added some features to his
1050 inspect module.
1051
1052- An updated python-mode.el version 4.1 which integrates Ken
1053 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1054 much nicer in XEmacs and Emacs. When stepping through your program
1055 with pdb, in either the shell window or the *Python* window, the
1056 source file and line will be tracked by an arrow. Very cool!
1057
1058- IDLE: syntax warnings in interactive mode are changed into errors.
1059
1060- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001061 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001062
1063- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001064
Barry Warsaw11e89c72001-04-11 20:37:57 +00001065
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001066What's New in Python 2.1 beta 2?
1067================================
1068
Guido van Rossum053ae352001-03-22 14:17:21 +00001069(Unlisted are many fixed bugs, more documentation, etc.)
1070
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001071Core language, builtins, and interpreter
1072
Guido van Rossum053ae352001-03-22 14:17:21 +00001073- The nested scopes work (enabled by "from __future__ import
1074 nested_scopes") is completed; in particular, the future now extends
1075 into code executed through exec, eval() and execfile(), and into the
1076 interactive interpreter.
1077
1078- When calling a base class method (e.g. BaseClass.__init__(self)),
1079 this is now allowed even if self is not strictly spoken a class
1080 instance (e.g. when using metaclasses or the Don Beaudry hook).
1081
1082- Slice objects are now comparable but not hashable; this prevents
1083 dict[:] from being accepted but meaningless.
1084
1085- Complex division is now calculated using less braindead algorithms.
1086 This doesn't change semantics except it's more likely to give useful
1087 results in extreme cases. Complex repr() now uses full precision
1088 like float repr().
1089
1090- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1091
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001092- It is illegal to assign to the name __debug__, which is set when the
1093 interpreter starts. It is effectively a compile-time constant.
1094
1095- A warning will be issued if a global statement for a variable
1096 follows a use or assignment of that variable.
1097
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001098Standard library
1099
Guido van Rossum053ae352001-03-22 14:17:21 +00001100- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1101 inspired by JUnit), is now part of the standard library. You now
1102 have a choice of two testing frameworks: unittest requires you to
1103 write testcases as separate code, doctest gathers them from
1104 docstrings. Both approaches have their advantages and
1105 disadvantages.
1106
1107- A new module Tix was added, which wraps the Tix extension library
1108 for Tk. With that module, it is not necessary to statically link
1109 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1110 require" command. See Demo/tix/.
1111
1112- tzparse.py is now obsolete.
1113
1114- In gzip.py, the seek() and tell() methods are removed -- they were
1115 non-functional anyway, and it's better if callers can test for their
1116 existence with hasattr().
1117
1118Python/C API
1119
1120- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1121 that's already in the dictionary during a PyDict_Next() iteration.
1122 This used to fail occasionally when a dictionary resize operation
1123 could be triggered that would rehash all the keys. All other
1124 modifications to the dictionary are still off-limits during a
1125 PyDict_Next() iteration!
1126
1127- New extended APIs related to passing compiler variables around.
1128
1129- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1130 implement isinstance() and issubclass().
1131
1132- Py_BuildValue() now has a "D" conversion to create a Python complex
1133 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001134
Fred Drake4e262a92001-03-22 18:26:47 +00001135- Extensions types which support weak references must now set the
1136 field allocated for the weak reference machinery to NULL themselves;
1137 this is done to avoid the cost of checking each object for having a
1138 weakly referencable type in PyObject_INIT(), since most types are
1139 not weakly referencable.
1140
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001141- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1142 free variables and cell variables to and from the frame's f_locals.
1143
1144- Variants of several functions defined in pythonrun.h have been added
1145 to support the nested_scopes future statement. The variants all end
1146 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1147 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1148 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001149 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001150
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001151Distutils
1152
1153- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1154 into the release tree.
1155
Tim Peters0e57abf2001-05-02 07:39:38 +00001156- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001157 (an uninstaller, more customization of the installer's display)
1158
1159- from Jack Jansen: added Mac-specific code to generate a dialog for
1160 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001161 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001162 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001163
1164- added 'platforms' and 'keywords' to the set of metadata that can be
1165 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001166
1167- applied patches from Jason Tishler to make the compiler class work with
1168 Cygwin.
1169
1170
Tim Peters2fe289a2001-03-01 22:19:38 +00001171What's New in Python 2.1 beta 1?
1172================================
Tim Petersd66595f2001-02-04 03:09:53 +00001173
1174Core language, builtins, and interpreter
1175
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001176- Following an outcry from the community about the amount of code
1177 broken by the nested scopes feature introduced in 2.1a2, we decided
1178 to make this feature optional, and to wait until Python 2.2 (or at
1179 least 6 months) to make it standard. The option can be enabled on a
1180 per-module basis by adding "from __future__ import nested_scopes" at
1181 the beginning of a module (before any other statements, but after
1182 comments and an optional docstring). See PEP 236 (Back to the
1183 __future__) for a description of the __future__ statement. PEP 227
1184 (Statically Nested Scopes) has been updated to reflect this change,
1185 and to clarify the semantics in a number of endcases.
1186
1187- The nested scopes code, when enabled, has been hardened, and most
1188 bugs and memory leaks in it have been fixed.
1189
1190- Compile-time warnings are now generated for a number of conditions
1191 that will break or change in meaning when nested scopes are enabled:
1192
1193 - Using "from...import *" or "exec" without in-clause in a function
1194 scope that also defines a lambda or nested function with one or
1195 more free (non-local) variables. The presence of the import* or
1196 bare exec makes it impossible for the compiler to determine the
1197 exact set of local variables in the outer scope, which makes it
1198 impossible to determine the bindings for free variables in the
1199 inner scope. To avoid the warning about import *, change it into
1200 an import of explicitly name object, or move the import* statement
1201 to the global scope; to avoid the warning about bare exec, use
1202 exec...in... (a good idea anyway -- there's a possibility that
1203 bare exec will be deprecated in the future).
1204
1205 - Use of a global variable in a nested scope with the same name as a
1206 local variable in a surrounding scope. This will change in
1207 meaning with nested scopes: the name in the inner scope will
1208 reference the variable in the outer scope rather than the global
1209 of the same name. To avoid the warning, either rename the outer
1210 variable, or use a global statement in the inner function.
1211
Neil Schemenauera35c6882001-02-27 04:45:05 +00001212- An optional object allocator has been included. This allocator is
1213 optimized for Python objects and should be faster and use less memory
1214 than the standard system allocator. It is not enabled by default
1215 because of possible thread safety problems. The allocator is only
1216 protected by the Python interpreter lock and it is possible that some
1217 extension modules require a thread safe allocator. The object
1218 allocator can be enabled by providing the "--with-pymalloc" option to
1219 configure.
1220
Tim Petersd66595f2001-02-04 03:09:53 +00001221Standard library
1222
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001223- pyexpat now detects the expat version if expat.h defines it. A
1224 number of additional handlers are provided, which are only available
1225 since expat 1.95. In addition, the methods SetParamEntityParsing and
1226 GetInputContext of Parser objects are available with 1.95.x
1227 only. Parser objects now provide the ordered_attributes and
1228 specified_attributes attributes. A new module expat.model was added,
1229 which offers a number of additional constants if 1.95.x is used.
1230
1231- xml.dom offers the new functions registerDOMImplementation and
1232 getDOMImplementation.
1233
1234- xml.dom.minidom offers a toprettyxml method. A number of DOM
1235 conformance issues have been resolved. In particular, Element now
1236 has an hasAttributes method, and the handling of namespaces was
1237 improved.
1238
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001239- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1240 getting information about live Python code, and pydoc.py, a module
1241 for interactively converting docstrings to HTML or text.
1242 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001243 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001244 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1245 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001246
Tim Peters1eff7962001-03-01 02:31:33 +00001247- New library module difflib.py, primarily packaging the SequenceMatcher
1248 class at the heart of the popular ndiff.py file-comparison tool.
1249
1250- doctest.py (a framework for verifying Python code examples in docstrings)
1251 is now part of the std library.
1252
Tim Petersd66595f2001-02-04 03:09:53 +00001253Windows changes
1254
Guido van Rossume3955a82001-03-02 14:05:59 +00001255- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1256 small GUI that lets you browse the module docstrings using your
1257 default web browser.
1258
Tim Peters1eff7962001-03-01 02:31:33 +00001259- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1260 Platforms) is implemented. See
1261
1262 http://python.sourceforge.net/peps/pep-0235.html
1263
1264 for full details, especially the "Current Lower-Left Semantics" section.
1265 The new Windows import rules are simpler than before:
1266
1267 A. If the PYTHONCASEOK environment variable exists, same as
1268 before: silently accept the first case-insensitive match of any
1269 kind; raise ImportError if none found.
1270
1271 B. Else search sys.path for the first case-sensitive match; raise
1272 ImportError if none found.
1273
1274 The same rules have been implented on other platforms with case-
1275 insensitive but case-preserving filesystems too (including Cygwin, and
1276 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001277
Tim Peters25a9ce32001-02-19 07:06:36 +00001278- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1279 what it's supposed to do (and does do under NT and 2000) via direct
1280 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001281 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001282 all Win9x systems before.
1283
Tim Peters1eff7962001-03-01 02:31:33 +00001284- Build: Subproject _test (effectively) renamed to _testcapi.
1285
Tim Peters2fe289a2001-03-01 22:19:38 +00001286New platforms
1287
1288- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1289 Thanks to Steven Majewski!
1290
1291- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1292 Tishler!
1293
Guido van Rossum9089b272001-03-02 06:49:50 +00001294- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1295 Schwertberger! See RISCOS/README for more information -- it seems
1296 that because of the bizarre filename conventions on RISCOS, no port
1297 to that platform is easy. Note that the new variable os.endsep is
1298 silently supported in order to make life easier on this platform,
1299 but we don't advertise it because it's not worth for most folks to
1300 care about RISCOS portability.
1301
Tim Peters25a9ce32001-02-19 07:06:36 +00001302
Tim Petersd7b5e882001-01-25 03:36:26 +00001303What's New in Python 2.1 alpha 2?
1304=================================
Tim Peters40ead762001-01-27 05:35:26 +00001305
Tim Petersd7b5e882001-01-25 03:36:26 +00001306Core language, builtins, and interpreter
1307
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001308- Scopes nest. If a name is used in a function or class, but is not
1309 local, the definition in the nearest enclosing function scope will
1310 be used. One consequence of this change is that lambda statements
1311 could reference variables in the namespaces where the lambda is
1312 defined. In some unusual cases, this change will break code.
1313
1314 In all previous version of Python, names were resolved in exactly
1315 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001316 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001317 function A is defined within a function B, the names bound in B are
1318 not visible in A. The new rules make names bound in B visible in A,
1319 unless A contains a name binding that hides the binding in B.
1320
1321 Section 4.1 of the reference manual describes the new scoping rules
1322 in detail. The test script in Lib/test/test_scope.py demonstrates
1323 some of the effects of the change.
1324
1325 The new rules will cause existing code to break if it defines nested
1326 functions where an outer function has local variables with the same
1327 name as globals or builtins used by the inner function. Example:
1328
1329 def munge(str):
1330 def helper(x):
1331 return str(x)
1332 if type(str) != type(''):
1333 str = helper(str)
1334 return str.strip()
1335
1336 Under the old rules, the name str in helper() is bound to the
1337 builtin function str(). Under the new rules, it will be bound to
1338 the argument named str and an error will occur when helper() is
1339 called.
1340
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001341- The compiler will report a SyntaxError if "from ... import *" occurs
1342 in a function or class scope. The language reference has documented
1343 that this case is illegal, but the compiler never checked for it.
1344 The recent introduction of nested scope makes the meaning of this
1345 form of name binding ambiguous. In a future release, the compiler
1346 may allow this form when there is no possibility of ambiguity.
1347
Tim Peters40ead762001-01-27 05:35:26 +00001348- repr(string) is easier to read, now using hex escapes instead of octal,
1349 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1350
1351 >>> "\texample \r\n" + chr(0) + chr(255)
1352 '\texample \r\n\x00\xff' # in 2.1
1353 '\011example \015\012\000\377' # in 2.0
1354
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001355- Functions are now compared and hashed by identity, not by value, since
1356 the func_code attribute is writable.
1357
Fred Drakefb9d7122001-02-01 20:00:40 +00001358- Weak references (PEP 205) have been added. This involves a few
1359 changes in the core, an extension module (_weakref), and a Python
1360 module (weakref). The weakref module is the public interface. It
1361 includes support for "explicit" weak references, proxy objects, and
1362 mappings with weakly held values.
1363
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001364- A 'continue' statement can now appear in a try block within the body
1365 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001366 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001367
Tim Petersd7b5e882001-01-25 03:36:26 +00001368Standard library
1369
Barry Warsaw30dbd142001-01-31 22:14:01 +00001370- mailbox.py now has a new class, PortableUnixMailbox which is
1371 identical to UnixMailbox but uses a more portable scheme for
1372 determining From_ separators. Also, the constructors for all the
1373 classes in this module have a new optional `factory' argument, which
1374 is a callable used when new message classes must be instantiated by
1375 the next() method.
1376
Tim Petersd7b5e882001-01-25 03:36:26 +00001377- random.py is now self-contained, and offers all the functionality of
1378 the now-deprecated whrandom.py. See the docs for details. random.py
1379 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001380 and restoring the internal state of the generator; and jumpahead(n),
1381 for quickly forcing the internal state to be the same as if n calls to
1382 random() had been made. The latter is particularly useful for multi-
1383 threaded programs, creating one instance of the random.Random() class for
1384 each thread, then using .jumpahead() to force each instance to use a
1385 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001386
Tim Peters0de88fc2001-02-01 04:59:18 +00001387- random.py's seed() function is new. For bit-for-bit compatibility with
1388 prior releases, use the whseed function instead. The new seed function
1389 addresses two problems: (1) The old function couldn't produce more than
1390 about 2**24 distinct internal states; the new one about 2**45 (the best
1391 that can be done in the Wichmann-Hill generator). (2) The old function
1392 sometimes produced identical internal states when passed distinct
1393 integers, and there was no simple way to predict when that would happen;
1394 the new one guarantees to produce distinct internal states for all
1395 arguments in [0, 27814431486576L).
1396
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001397- The socket module now supports raw packets on Linux. The socket
1398 family is AF_PACKET.
1399
Tim Peters9ea17ac2001-02-02 05:57:15 +00001400- test_capi.py is a start at running tests of the Python C API. The tests
1401 are implemented by the new Modules/_testmodule.c.
1402
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001403- A new extension module, _symtable, provides provisional access to the
1404 internal symbol table used by the Python compiler. A higher-level
1405 interface will be added on top of _symtable in a future release.
1406
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001407- Removed the obsolete soundex module.
1408
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001409- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1410 the isSameNode method; NamedNodeMap the get method.
1411
1412- xml.sax.expatreader supports the lexical handler property; it
1413 generates comment, startCDATA, and endCDATA events.
1414
Tim Petersee826f82001-01-31 19:39:44 +00001415Windows changes
1416
1417- Build procedure: the zlib project is built in a different way that
1418 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001419 the zlib binary used. See PCbuild\readme.txt for details. Your old
1420 zlib-related directories can be deleted; you'll need to download fresh
1421 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001422
Tim Peters9ea17ac2001-02-02 05:57:15 +00001423- Build: New subproject _test for the benefit of test_capi.py (see above).
1424
Tim Petersb16c56f2001-02-02 21:24:51 +00001425- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1426 interface to some Python compiler internals).
1427
1428- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001429 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001430
Tim Petersa3a3a032000-11-30 05:22:44 +00001431What's New in Python 2.1 alpha 1?
1432=================================
1433
1434Core language, builtins, and interpreter
1435
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001436- There is a new Unicode companion to the PyObject_Str() API
1437 called PyObject_Unicode(). It behaves in the same way as the
1438 former, but assures that the returned value is an Unicode object
1439 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001440
Guido van Rossumf98eda02001-01-17 15:54:45 +00001441- The comparison operators support "rich comparison overloading" (PEP
1442 207). C extension types can provide a rich comparison function in
1443 the new tp_richcompare slot in the type object. The cmp() function
1444 and the C function PyObject_Compare() first try the new rich
1445 comparison operators before trying the old 3-way comparison. There
1446 is also a new C API PyObject_RichCompare() (which also falls back on
1447 the old 3-way comparison, but does not constrain the outcome of the
1448 rich comparison to a Boolean result).
1449
1450 The rich comparison function takes two objects (at least one of
1451 which is guaranteed to have the type that provided the function) and
1452 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1453 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1454 object, which may be NotImplemented (in which case the tp_compare
1455 slot function is used as a fallback, if defined).
1456
1457 Classes can overload individual comparison operators by defining one
1458 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001459 __ge__. There are no explicit "reflected argument" versions of
1460 these; instead, __lt__ and __gt__ are each other's reflection,
1461 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1462 reflection (similar at the C level). No other implications are
1463 made; in particular, Python does not assume that == is the Boolean
1464 inverse of !=, or that < is the Boolean inverse of >=. This makes
1465 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001466
1467 Classes or types that want to implement (in)equality tests but not
1468 the ordering operators (i.e. unordered types) should implement ==
1469 and !=, and raise an error for the ordering operators.
1470
Guido van Rossuma88479f2001-01-18 14:28:08 +00001471 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001472 Boolean; e.g. a matrix type might want to return a matrix of bits
1473 for A < B, giving elementwise comparisons. Such types should ensure
1474 that any interpretation of their value in a Boolean context raises
1475 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1476 at the C level) to always raise an exception.
1477
Guido van Rossuma88479f2001-01-18 14:28:08 +00001478- Complex numbers use rich comparisons to define == and != but raise
1479 an exception for <, <=, > and >=. Unfortunately, this also means
1480 that cmp() of two complex numbers raises an exception when the two
1481 numbers differ. Since it is not mathematically meaningful to compare
1482 complex numbers except for equality, I hope that this doesn't break
1483 too much code.
1484
Tim Peters3389f192001-02-18 08:48:49 +00001485- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001486 not defined by the language, other than that it's arbitrary but
1487 consistent (see the Reference Manual). An implementation detail changed
1488 in 2.1a1 such that None now compares less than any other object. Code
1489 relying on this new behavior (like code that relied on the previous
1490 behavior) does so at its own risk.
1491
Barry Warsaw573b5412001-01-15 20:43:18 +00001492- Functions and methods now support getting and setting arbitrarily
1493 named attributes (PEP 232). Functions have a new __dict__
1494 (a.k.a. func_dict) which hold the function attributes. Methods get
1495 and set attributes on their underlying im_func. It is a TypeError
1496 to set an attribute on a bound method.
1497
Guido van Rossum051e3352001-01-15 19:11:10 +00001498- The xrange() object implementation has been improved so that
1499 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1500 limitation that in this case len(xrange(sys.maxint)) can't be
1501 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1502 work fine as long as the index i doesn't actually reach 2**31.
1503 (Python uses regular ints for sequence and string indices; fixing
1504 that is much more work.)
1505
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001506- Two changes to from...import:
1507
Guido van Rossumba381232001-02-03 15:06:40 +00001508 1) "from M import X" now works even if (after loading module M)
1509 sys.modules['M'] is not a real module; it's basically a getattr()
1510 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001511
1512 2) "from M import *" now looks for M.__all__ to decide which names to
1513 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1514 filters out names starting with '_' as before. Whether or not
1515 __all__ exists, there's no restriction on the type of M.
1516
Guido van Rossumf61f1662001-01-10 20:13:55 +00001517- File objects have a new method, xreadlines(). This is the fastest
1518 way to iterate over all lines in a file:
1519
1520 for line in file.xreadlines():
1521 ...do something to line...
1522
1523 See the xreadlines module (mentioned below) for how to do this for
1524 other file-like objects.
1525
1526- Even if you don't use file.xreadlines(), you may expect a speedup on
1527 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001528 quite a bit in platform-specific ways: on systems (like Linux) that
1529 support flockfile(), getc_unlocked(), and funlockfile(), those are
1530 used by default. On systems (like Windows) without getc_unlocked(),
1531 a complicated (but still thread-safe) method using fgets() is used by
1532 default.
1533
Tim Petersd52269b2001-01-25 06:23:18 +00001534 You can force use of the fgets() method by #define'ing
1535 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001536 getc_unlocked()).
1537
Tim Petersd52269b2001-01-25 06:23:18 +00001538 You can force fgets() not to be used by #define'ing
1539 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001540 test_bufio.py fails -- and let us know if it does!).
1541
1542- In addition, the fileinput module, while still slower than the other
1543 methods on most platforms, has been sped up too, by using
1544 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001545
1546- Support for run-time warnings has been added, including a new
1547 command line option (-W) to specify the disposition of warnings.
1548 See the description of the warnings module below.
1549
1550- Extensive changes have been made to the coercion code. This mostly
1551 affects extension modules (which can now implement mixed-type
1552 numerical operators without having to use coercion), but
1553 occasionally, in boundary cases the coercion semantics have changed
1554 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001555 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001556 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001557 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001558
Guido van Rossumf98eda02001-01-17 15:54:45 +00001559- In connection with the coercion changes, a new built-in singleton
1560 object, NotImplemented is defined. This can be returned for
1561 operations that wish to indicate they are not implemented for a
1562 particular combination of arguments. From C, this is
1563 Py_NotImplemented.
1564
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001565- The interpreter accepts now bytecode files on the command line even
1566 if they do not have a .pyc or .pyo extension. On Linux, after executing
1567
Martin v. Löwise214baa2001-02-04 22:37:56 +00001568import imp,sys,string
1569magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1570reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1571open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001572
1573 any byte code file can be used as an executable (i.e. as an argument
1574 to execve(2)).
1575
Tim Peters9940b802000-12-01 07:59:35 +00001576- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001577 character. In 1.6 and earlier, they never produced a sign,
1578 and raised an error if the value of the long was too large
1579 to fit in a Python int. In 2.0, they produced a sign if and
1580 only if too large to fit in an int. This was inconsistent
1581 across platforms (because the size of an int varies across
1582 platforms), and inconsistent with hex() and oct(). Example:
1583
1584 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001585 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001586 'ffffffbe' # in 2.0 and before, on 32-bit machines
1587 >>> hex(-0x42L)
1588 '-0x42L' # in all versions of Python
1589
Tim Peters9940b802000-12-01 07:59:35 +00001590 The behavior of %d formats for negative Python longs remains
1591 the same as in 2.0 (although in 1.6 and before, they raised
1592 an error if the long didn't fit in a Python int).
1593
1594 %u formats don't make sense for Python longs, but are allowed
1595 and treated the same as %d in 2.1. In 2.0, a negative long
1596 formatted via %u produced a sign if and only if too large to
1597 fit in an int. In 1.6 and earlier, a negative long formatted
1598 via %u raised an error if it was too big to fit in an int.
1599
Guido van Rossum3661d392000-12-12 22:10:31 +00001600- Dictionary objects have an odd new method, popitem(). This removes
1601 an arbitrary item from the dictionary and returns it (in the form of
1602 a (key, value) pair). This can be useful for algorithms that use a
1603 dictionary as a bag of "to do" items and repeatedly need to pick one
1604 item. Such algorithms normally end up running in quadratic time;
1605 using popitem() they can usually be made to run in linear time.
1606
Tim Peters36cdad12000-12-29 02:06:45 +00001607Standard library
1608
Thomas Woutersfe385252001-01-19 23:16:56 +00001609- In the time module, the time argument to the functions strftime,
1610 localtime, gmtime, asctime and ctime is now optional, defaulting to
1611 the current time (in the local timezone).
1612
Guido van Rossumda91f222001-01-15 16:36:08 +00001613- The ftplib module now defaults to passive mode, which is deemed a
1614 more useful default given that clients are often inside firewalls
1615 these days. Note that this could break if ftplib is used to connect
1616 to a *server* that is inside a firewall, from outside; this is
1617 expected to be a very rare situation. To fix that, you can call
1618 ftp.set_pasv(0).
1619
Martin v. Löwis10a27872001-01-13 09:54:41 +00001620- The module site now treats .pth files not only for path configuration,
1621 but also supports extensions to the initialization code: Lines starting
1622 with import are executed.
1623
Guido van Rossumf61f1662001-01-10 20:13:55 +00001624- There's a new module, warnings, which implements a mechanism for
1625 issuing and filtering warnings. There are some new built-in
1626 exceptions that serve as warning categories, and a new command line
1627 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1628 turns warnings into errors). warnings.warn(message[, category])
1629 issues a warning message; this can also be called from C as
1630 PyErr_Warn(category, message).
1631
1632- A new module xreadlines was added. This exports a single factory
1633 function, xreadlines(). The intention is that this code is the
1634 absolutely fastest way to iterate over all lines in an open
1635 file(-like) object:
1636
1637 import xreadlines
1638 for line in xreadlines.xreadlines(file):
1639 ...do something to line...
1640
1641 This is equivalent to the previous the speed record holder using
1642 file.readlines(sizehint). Note that if file is a real file object
1643 (as opposed to a file-like object), this is equivalent:
1644
1645 for line in file.xreadlines():
1646 ...do something to line...
1647
Tim Peters36cdad12000-12-29 02:06:45 +00001648- The bisect module has new functions bisect_left, insort_left,
1649 bisect_right and insort_right. The old names bisect and insort
1650 are now aliases for bisect_right and insort_right. XXX_right
1651 and XXX_left methods differ in what happens when the new element
1652 compares equal to one or more elements already in the list: the
1653 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001654 right. Code that doesn't care where equal elements end up should
1655 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001656
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001657- The new curses.panel module wraps the panel library that forms part
1658 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1659
Guido van Rossumf61f1662001-01-10 20:13:55 +00001660- The SocketServer module now sets the allow_reuse_address flag by
1661 default in the TCPServer class.
1662
1663- A new function, sys._getframe(), returns the stack frame pointer of
1664 the caller. This is intended only as a building block for
1665 higher-level mechanisms such as string interpolation.
1666
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001667- The pyexpat module supports a number of new handlers, which are
1668 available only in expat 1.2. If invocation of a callback fails, it
1669 will report an additional frame in the traceback. Parser objects
1670 participate now in garbage collection. If expat reports an unknown
1671 encoding, pyexpat will try to use a Python codec; that works only
1672 for single-byte charsets. The parser type objects is exposed as
1673 XMLParserObject.
1674
1675- xml.dom now offers standard definitions for symbolic node type and
1676 exception code constants, and a hierarchy of DOM exceptions. minidom
1677 was adjusted to use them.
1678
1679- The conformance of xml.dom.minidom to the DOM specification was
1680 improved. It detects a number of additional error cases; the
1681 previous/next relationship works even when the tree is modified;
1682 Node supports the normalize() method; NamedNodeMap, DocumentType and
1683 DOMImplementation classes were added; Element supports the
1684 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1685 method.
1686
Guido van Rossumf61f1662001-01-10 20:13:55 +00001687Build issues
1688
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001689- For Unix (and Unix-compatible) builds, configuration and building of
1690 extension modules is now greatly automated. Rather than having to
1691 edit the Modules/Setup file to indicate which modules should be
1692 built and where their include files and libraries are, a
1693 distutils-based setup.py script now takes care of building most
1694 extension modules. All extension modules built this way are built
1695 as shared libraries. Only a few modules that must be linked
1696 statically are still listed in the Setup file; you won't need to
1697 edit their configuration.
1698
1699- Python should now build out of the box on Cygwin. If it doesn't,
1700 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001701
1702- Python now always uses its own (renamed) implementation of getopt()
1703 -- there's too much variation among C library getopt()
1704 implementations.
1705
1706- C++ compilers are better supported; the CXX macro is always set to a
1707 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001708
Tim Petersd92dfe02000-12-12 01:18:41 +00001709Windows changes
1710
1711- select module: By default under Windows, a select() call
1712 can specify no more than 64 sockets. Python now boosts
1713 this Microsoft default to 512. If you need even more than
1714 that, see the MS docs (you'll need to #define FD_SETSIZE
1715 and recompile Python from source).
1716
Guido van Rossumf61f1662001-01-10 20:13:55 +00001717- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1718 subdirectory is no more!
1719
Tim Petersa3a3a032000-11-30 05:22:44 +00001720
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001721What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001722=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001723
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001724Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001725changes are in the file HISTORY. If you are making the jump directly
1726from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1727HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001728
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001729Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1730the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1731http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001732
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001733--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001734
1735======================================================================
1736
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001737What's new in 2.0 (since release candidate 1)?
1738==============================================
1739
1740Standard library
1741
1742- The copy_reg module was modified to clarify its intended use: to
1743 register pickle support for extension types, not for classes.
1744 pickle() will raise a TypeError if it is passed a class.
1745
1746- Fixed a bug in gettext's "normalize and expand" code that prevented
1747 it from finding an existing .mo file.
1748
1749- Restored support for HTTP/0.9 servers in httplib.
1750
Tim Peters989b7b92000-10-16 20:24:53 +00001751- The math module was changed to stop raising OverflowError in case of
1752 underflow, and return 0 instead in underflow cases. Whether Python
1753 used to raise OverflowError in case of underflow was platform-
1754 dependent (it did when the platform math library set errno to ERANGE
1755 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001756
1757- Fixed a bug in StringIO that occurred when the file position was not
1758 at the end of the file and write() was called with enough data to
1759 extend past the end of the file.
1760
1761- Fixed a bug that caused Tkinter error messages to get lost on
1762 Windows. The bug was fixed by replacing direct use of
1763 interp->result with Tcl_GetStringResult(interp).
1764
1765- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1766 redirect response.
1767
1768- Several changes were made to distutils: Some debugging code was
1769 removed from util. Fixed the installer used when an external zip
1770 program (like WinZip) is not found; the source code for this
1771 installer is in Misc/distutils. check_lib() was modified to behave
1772 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1773 test for whether installed modules are on sys.path was changed to
1774 use both normcase() and normpath().
1775
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001776- Several minor bugs were fixed in the xml package (the minidom,
1777 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001778
1779- The regression test driver (regrtest.py) behavior when invoked with
1780 -l changed: It now reports a count of objects that are recognized as
1781 garbage but not freed by the garbage collector.
1782
Tim Peters989b7b92000-10-16 20:24:53 +00001783- The regression test for the math module was changed to test
1784 exceptional behavior when the test is run in verbose mode. Python
1785 cannot yet guarantee consistent exception behavior across platforms,
1786 so the exception part of test_math is run only in verbose mode, and
1787 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001788
1789Internals
1790
1791- PyOS_CheckStack() has been disabled on Win64, where it caused
1792 test_sre to fail.
1793
1794Build issues
1795
1796- Changed compiler flags, so that gcc is always invoked with -Wall and
1797 -Wstrict-prototypes. Users compiling Python with GCC should see
1798 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001799 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001800 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001801
Tim Petersa3a3a032000-11-30 05:22:44 +00001802- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001803
1804Tools and other miscellany
1805
1806- The compiler in Tools/compiler was updated to support the new
1807 language features introduced in 2.0: extended print statement, list
1808 comprehensions, and augmented assignments. The new compiler should
1809 also be backwards compatible with Python 1.5.2; the compiler will
1810 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001811 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001812
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001813What's new in 2.0 release candidate 1 (since beta 2)?
1814=====================================================
1815
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001816What is release candidate 1?
1817
1818We believe that release candidate 1 will fix all known bugs that we
1819intend to fix for the 2.0 final release. This release should be a bit
1820more stable than the previous betas. We would like to see even more
1821widespread testing before the final release, so we are producing this
1822release candidate. The final release will be exactly the same unless
1823any show-stopping (or brown bag) bugs are found by testers of the
1824release candidate.
1825
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001826All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001827to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001828
1829Core language, builtins, and interpreter
1830
1831- A bug that caused crashes when __coerce__ was used with augmented
1832 assignment, e.g. +=, was fixed.
1833
1834- Raise ZeroDivisionError when raising zero to a negative number,
1835 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1836 power operator and the result of math.pow(0.0, -2.0) will vary by
1837 platform. On Linux, it raises a ValueError.
1838
1839- A bug in Unicode string interpolation was fixed that occasionally
1840 caused errors with formats including "%%". For example, the
1841 following expression "%% %s" % u"abc" no longer raises a TypeError.
1842
1843- Compilation of deeply nested expressions raises MemoryError instead
1844 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1845
1846- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1847 rendering them useless. They are now written in binary mode again.
1848
1849Standard library
1850
1851- Keyword arguments are now accepted for most pattern and match object
1852 methods in SRE, the standard regular expression engine.
1853
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001854- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001855 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001856
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001857- Several bugs in the Unicode handling and error handling in _tkinter
1858 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001859
1860- Fix memory management errors in Merge() and Tkapp_Call() routines.
1861
1862- Several changes were made to cStringIO to make it compatible with
1863 the file-like object interface and with StringIO. If operations are
1864 performed on a closed object, an exception is raised. The truncate
1865 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001866 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001867
1868- There were many changes made to the linuxaudiodev module and its
1869 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001870 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001871
1872 Note that this module is named poorly, because it should work
1873 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001874 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001875
1876 The module now raises exceptions when errors occur instead of
1877 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1878 audio) and defines a getptr() method that calls the
1879 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1880
1881- The library_version attribute, introduced in an earlier beta, was
1882 removed because it can not be supported with early versions of the C
1883 readline library, which provides no way to determine the version at
1884 compile-time.
1885
1886- The binascii module is now enabled on Win64.
1887
Tim Peters46446d62000-10-09 21:19:31 +00001888- tokenize.py no longer suffers "recursion depth" errors when parsing
1889 programs with very long string literals.
1890
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001891Internals
1892
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001893- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001894 which is called when the interpreter starts up to determine where
1895 the standard library is installed. These vulnerabilities affect all
1896 previous versions of Python and can be exploited by setting very
1897 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1898 setuid Python script, although use of the wrapper in
1899 Misc/setuid-prog.c will eliminate the vulnerability.
1900
1901- Fixed garbage collection bugs in instance creation that were
1902 triggered when errors occurred during initialization. The solution,
1903 applied in cPickle and in PyInstance_New(), is to call
1904 PyObject_GC_Init() after the initialization of the object's
1905 container attributes is complete.
1906
1907- pyexpat adds definitions of PyModule_AddStringConstant and
1908 PyModule_AddObject if the Python version is less than 2.0, which
1909 provides compatibility with PyXML on Python 1.5.2.
1910
1911- If the platform has a bogus definition for LONG_BIT (the number of
1912 bits in a long), an error will be reported at compile time.
1913
1914- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1915 collection crashes and possibly other, unreported crashes.
1916
1917- Fixed a memory leak in _PyUnicode_Fini().
1918
1919Build issues
1920
1921- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001922 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001923 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001924
1925- The mmap.PAGESIZE constant is now initialized using sysconf when
1926 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1927
1928- The md5 file should now compile on all platforms.
1929
1930- The select module now compiles on platforms that do not define
1931 POLLRDNORM and related constants.
1932
1933- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001934 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001935
Jeremy Hylton10921202000-10-09 18:34:12 +00001936- BeOS: A number of changes were made to the build and installation
1937 process. ar-fake now operates on a directory of object files.
1938 dl_export.h is gone, and its macros now appear on the mwcc command
1939 line during build on PPC BeOS.
1940
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001941- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001942 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001943
1944- Cygwin: Support for shared libraries, Tkinter, and sockets.
1945
1946- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1947
1948Tools and other miscellany
1949
1950- Removed debugging prints from main used with freeze.
1951
Tim Peters46446d62000-10-09 21:19:31 +00001952- IDLE auto-indent no longer crashes when it encounters Unicode
1953 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001954
1955What's new in 2.0 beta 2 (since beta 1)?
1956========================================
1957
1958Core language, builtins, and interpreter
1959
Tim Peters482c0212000-09-26 06:33:09 +00001960- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001961 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001962
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001963- Add -h and -V command line options to print the usage message and
1964 Python version number and exit immediately.
1965
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001966- eval() and exec accept Unicode objects as code parameters.
1967
1968- getattr() and setattr() now also accept Unicode objects for the
1969 attribute name, which are converted to strings using the default
1970 encoding before lookup.
1971
1972- Multiplication on string and Unicode now does proper bounds
1973 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1974 string is too long."
1975
1976- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001977 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001978
Jeremy Hylton1b618592000-09-26 05:32:36 +00001979
1980Standard library and extensions
1981
Guido van Rossum5b08f132001-04-16 02:05:23 +00001982- socket module: the OpenSSL code now adds support for RAND_status()
1983 and EGD (Entropy Gathering Device).
1984
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001985- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001986 argument checking; it still takes no arguments.
1987
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001988- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001989
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001990- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001991
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001992- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001993
1994- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001995 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001996
1997- copy: Copy Unicode objects atomically.
1998
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001999- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002000
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002001- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002002
Fred Drake67233bc2000-09-26 16:40:27 +00002003- dbm: Add get() and setdefault() methods to dbm object. Add constant
2004 `library' to module that names the library used. Added doc strings
2005 and method names to error messages. Uses configure to determine
2006 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2007 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002008
2009- distutils: Update to version 0.9.3.
2010
2011- dl: Add several dl.RTLD_ constants.
2012
2013- fpectl: Now supported on FreeBSD.
2014
2015- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2016 found by the collector will be saved in gc.garbage. This is useful
2017 for debugging a program that creates reference cycles.
2018
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002019- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002020 of HTTP class. Do not close socket on zero-length response. Do not
2021 crash when server sends invalid content-length header.
2022
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002023- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002024
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002025- marshal: When reading a short, sign-extend on platforms where shorts
2026 are bigger than 16 bits. When reading a long, repair the unportable
2027 sign extension that was being done for 64-bit machines. (It assumed
2028 that signed right shift sign-extends.)
2029
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002030- operator: Add contains(), invert(), __invert__() as aliases for
2031 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002032
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002033- os: Add support for popen2() and popen3() on all platforms where
2034 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002035
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002036- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002037 clicking on a file in Explorer (or passing the file name to the
2038 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002039
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002040- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002041 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002042
2043- pickle: Now raises ValueError when an invalid pickle that contains
2044 a non-string repr where a string repr was expected. This behavior
2045 matches cPickle.
2046
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002047- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002048
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002049- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002050
2051- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002052 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002053 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002054
2055- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002056 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002057
2058- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002059 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002060 few cycles during startup since the first call to
2061 setdefaultencoding() will initialize the codec registry and the
2062 encodings package.
2063
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002064- socket: Support for size hint in readlines() method of object returned
2065 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002066
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002067- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002068 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002069 is followed by whitespace.
2070
Tim Petersa3a3a032000-11-30 05:22:44 +00002071- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002072
2073- struct: Check ranges for bytes and shorts.
2074
2075- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002076 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002077
2078- Tkinter: Image objects are now guaranteed to have unique ids. Set
2079 event.delta to zero if Tk version doesn't support mousewheel.
2080 Removed some debugging prints.
2081
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002082- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002083
Fred Drake67233bc2000-09-26 16:40:27 +00002084- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002085 which works around a bug in Norton AntiVirus 2000 that leads directly
2086 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002087
2088- xml: New version detection code allows PyXML to override standard
2089 XML package if PyXML version is greater than 0.6.1.
2090
Fred Drake64bb3802000-09-26 16:21:35 +00002091- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2092 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2093 tree only for nodes which are sufficiently interesting to a specific
2094 application. Does not provide the HTML-specific extensions. Still
2095 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002096
Fred Drake64bb3802000-09-26 16:21:35 +00002097- xml.sax: SAX 2 support for Python, including all the handler
2098 interfaces needed to process XML 1.0 compliant XML. Some
2099 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002100
Fred Drake64bb3802000-09-26 16:21:35 +00002101- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2102 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002103
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002104
Jeremy Hylton1b618592000-09-26 05:32:36 +00002105C API
2106
2107- Add three new convenience functions for module initialization --
2108 PyModule_AddObject(), PyModule_AddIntConstant(), and
2109 PyModule_AddStringConstant().
2110
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002111- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002112 removed and add #error to Python.h if NULL isn't defined after
2113 #include of stdio.h.
2114
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002115- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002116 backwards compatibility (at the source level) with old extensions.
2117
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002118- A wrapper API was added for signal() and sigaction(). Instead of
2119 either function, always use PyOS_getsig() to get a signal handler
2120 and PyOS_setsig() to set one. A new convenience typedef
2121 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002122
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002123- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002124 internal data buffer and size of a string object -- or the default
2125 encoded version of a Unicode object.
2126
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002127- PyString_Size() and PyString_AsString() accept Unicode objects.
2128
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002129- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002130 exists). INT_MAX and LONG_MAX will always be defined, even if
2131 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002132
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002133- PyFloat_FromString takes a second argument, pend, that was
2134 effectively useless. It is now officially useless but preserved for
2135 backwards compatibility. If the pend argument is not NULL, *pend is
2136 set to NULL.
2137
2138- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2139 for the attribute name. See note on getattr() above.
2140
2141- A few bug fixes to argument processing for Unicode.
2142 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2143 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2144 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002145 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002146
2147- Py_BuildValue accepts B format (for bgen-generated code).
2148
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002149
Jeremy Hylton1b618592000-09-26 05:32:36 +00002150Internals
2151
2152- On Unix, fix code for finding Python installation directory so that
2153 it works when argv[0] is a relative path.
2154
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002155- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002156 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002157 rather than by generating a copy of the object.
2158
Tim Peters482c0212000-09-26 06:33:09 +00002159- Several of the internal Unicode tables are much smaller now, and
2160 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002161
Jeremy Hylton97693b02000-09-26 17:42:51 +00002162- In the garbage collector: Fixed bug in collection of tuples. Fixed
2163 bug that caused some instances to be removed from the container set
2164 while they were still live. Fixed parsing in gc.set_debug() for
2165 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002166
2167- Fixed refcount problem in instance deallocation that only occurred
2168 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2169
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002170- On Windows, getpythonregpath is now protected against null data in
2171 registry key.
2172
2173- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002174 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002175
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002176
Jeremy Hylton1b618592000-09-26 05:32:36 +00002177Build and platform-specific issues
2178
2179- Better support of GNU Pth via --with-pth configure option.
2180
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002181- Python/C API now properly exposed to dynamically-loaded extension
2182 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002183
2184- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2185 Don't define MS_SYNC to be zero when it is undefined. Added missing
2186 prototypes in posixmodule.c.
2187
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002188- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002189 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002190
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002191- Fix largefile support on older NetBSD systems and OpenBSD by adding
2192 define for TELL64.
2193
2194
2195Tools and other miscellany
2196
2197- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2198
2199- freeze: The modulefinder now works with 2.0 opcodes.
2200
Tim Petersa3a3a032000-11-30 05:22:44 +00002201- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002202 Move hackery of sys.argv until after the Tk instance has been
2203 created, which allows the application-specific Tkinter
2204 initialization to be executed if present; also pass an explicit
2205 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002206
Jeremy Hylton1b618592000-09-26 05:32:36 +00002207
2208What's new in 2.0 beta 1?
2209=========================
2210
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002211Source Incompatibilities
2212------------------------
2213
2214None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2215such as single-argument append(), connect() and bind(), and changes to
2216str(long) and repr(float).
2217
2218
2219Binary Incompatibilities
2220------------------------
2221
2222- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2223with Python 2.0; these extensions will have to be rebuilt for Python
22242.0.
2225
2226- On Windows, attempting to import a third party extension built for
2227Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2228can do about this. Check your PYTHONPATH environment variable!
2229
2230- Python bytecode files (*.pyc and *.pyo) are not compatible between
2231releases.
2232
2233
2234Overview of Changes Since 1.6
2235-----------------------------
2236
2237There are many new modules (including brand new XML support through
2238the xml package, and i18n support through the gettext module); a list
2239of all new modules is included below. Lots of bugs have been fixed.
2240
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002241The process for making major new changes to the language has changed
2242since Python 1.6. Enhancements must now be documented by a Python
2243Enhancement Proposal (PEP) before they can be accepted.
2244
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002245There are several important syntax enhancements, described in more
2246detail below:
2247
2248 - Augmented assignment, e.g. x += 1
2249
2250 - List comprehensions, e.g. [x**2 for x in range(10)]
2251
2252 - Extended import statement, e.g. import Module as Name
2253
2254 - Extended print statement, e.g. print >> file, "Hello"
2255
2256Other important changes:
2257
2258 - Optional collection of cyclical garbage
2259
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002260Python Enhancement Proposal (PEP)
2261---------------------------------
2262
2263PEP stands for Python Enhancement Proposal. A PEP is a design
2264document providing information to the Python community, or describing
2265a new feature for Python. The PEP should provide a concise technical
2266specification of the feature and a rationale for the feature.
2267
2268We intend PEPs to be the primary mechanisms for proposing new
2269features, for collecting community input on an issue, and for
2270documenting the design decisions that have gone into Python. The PEP
2271author is responsible for building consensus within the community and
2272documenting dissenting opinions.
2273
2274The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002275
2276Augmented Assignment
2277--------------------
2278
2279This must have been the most-requested feature of the past years!
2280Eleven new assignment operators were added:
2281
Guido van Rossume905e952000-09-05 12:42:46 +00002282 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002283
2284For example,
2285
2286 A += B
2287
2288is similar to
2289
2290 A = A + B
2291
2292except that A is evaluated only once (relevant when A is something
2293like dict[index].attr).
2294
2295However, if A is a mutable object, A may be modified in place. Thus,
2296if A is a number or a string, A += B has the same effect as A = A+B
2297(except A is only evaluated once); but if a is a list, A += B has the
2298same effect as A.extend(B)!
2299
2300Classes and built-in object types can override the new operators in
2301order to implement the in-place behavior; the not-in-place behavior is
2302used automatically as a fallback when an object doesn't implement the
2303in-place behavior. For classes, the method name is derived from the
2304method name for the corresponding not-in-place operator by inserting
2305an 'i' in front of the name, e.g. __iadd__ implements in-place
2306__add__.
2307
2308Augmented assignment was implemented by Thomas Wouters.
2309
2310
2311List Comprehensions
2312-------------------
2313
2314This is a flexible new notation for lists whose elements are computed
2315from another list (or lists). The simplest form is:
2316
2317 [<expression> for <variable> in <sequence>]
2318
Guido van Rossum56db0952000-09-06 23:34:25 +00002319For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002320This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002321
2322You can also add a condition:
2323
2324 [<expression> for <variable> in <sequence> if <condition>]
2325
2326For example, [w for w in words if w == w.lower()] would yield the list
2327of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002328than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002329
2330You can also have nested for loops and more than one 'if' clause. For
2331example, here's a function that flattens a sequence of sequences::
2332
2333 def flatten(seq):
2334 return [x for subseq in seq for x in subseq]
2335
2336 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2337
2338This prints
2339
2340 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2341
2342List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002343Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002344
2345
2346Extended Import Statement
2347-------------------------
2348
2349Many people have asked for a way to import a module under a different
2350name. This can be accomplished like this:
2351
2352 import foo
2353 bar = foo
2354 del foo
2355
2356but this common idiom gets old quickly. A simple extension of the
2357import statement now allows this to be written as follows:
2358
2359 import foo as bar
2360
2361There's also a variant for 'from ... import':
2362
2363 from foo import bar as spam
2364
2365This also works with packages; e.g. you can write this:
2366
2367 import test.regrtest as regrtest
2368
2369Note that 'as' is not a new keyword -- it is recognized only in this
2370context (this is only possible because the syntax for the import
2371statement doesn't involve expressions).
2372
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002373Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002374
2375
2376Extended Print Statement
2377------------------------
2378
2379Easily the most controversial new feature, this extension to the print
2380statement adds an option to make the output go to a different file
2381than the default sys.stdout.
2382
2383For example, to write an error message to sys.stderr, you can now
2384write:
2385
2386 print >> sys.stderr, "Error: bad dog!"
2387
2388As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002389evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002390
2391 print >> None, "Hello world"
2392
2393is equivalent to
2394
2395 print "Hello world"
2396
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002397Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002398
2399
2400Optional Collection of Cyclical Garbage
2401---------------------------------------
2402
2403Python is now equipped with a garbage collector that can hunt down
2404cyclical references between Python objects. It's no replacement for
2405reference counting; in fact, it depends on the reference counts being
2406correct, and decides that a set of objects belong to a cycle if all
2407their reference counts can be accounted for from their references to
2408each other. This devious scheme was first proposed by Eric Tiedemann,
2409and brought to implementation by Neil Schemenauer.
2410
2411There's a module "gc" that lets you control some parameters of the
2412garbage collection. There's also an option to the configure script
2413that lets you enable or disable the garbage collection. In 2.0b1,
2414it's on by default, so that we (hopefully) can collect decent user
2415experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002416performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002417off by default in the final 2.0 release.
2418
2419
2420Smaller Changes
2421---------------
2422
2423A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2424map(None, seq1, seq2, ...) when the sequences have the same length;
2425i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2426the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002427zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002428
2429sys.version_info is a tuple (major, minor, micro, level, serial).
2430
2431Dictionaries have an odd new method, setdefault(key, default).
2432dict.setdefault(key, default) returns dict[key] if it exists; if not,
2433it sets dict[key] to default and returns that value. Thus:
2434
2435 dict.setdefault(key, []).append(item)
2436
2437does the same work as this common idiom:
2438
2439 if not dict.has_key(key):
2440 dict[key] = []
2441 dict[key].append(item)
2442
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002443There are two new variants of SyntaxError that are raised for
2444indentation-related errors: IndentationError and TabError.
2445
2446Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2447escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002448
2449The limits on the size of expressions and file in Python source code
2450have been raised from 2**16 to 2**32. Previous versions of Python
2451were limited because the maximum argument size the Python VM accepted
2452was 2**16. This limited the size of object constructor expressions,
2453e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2454limit was raised thanks to a patch by Charles Waldman that effectively
2455fixes the problem. It is now much more likely that you will be
2456limited by available memory than by an arbitrary limit in Python.
2457
2458The interpreter's maximum recursion depth can be modified by Python
2459programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2460limit is the maximum number of recursive calls that can be made by
2461Python code. The limit exists to prevent infinite recursion from
2462overflowing the C stack and causing a core dump. The default value is
24631000. The maximum safe value for a particular platform can be found
2464by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002465
2466New Modules and Packages
2467------------------------
2468
2469atexit - for registering functions to be called when Python exits.
2470
2471imputil - Greg Stein's alternative API for writing custom import
2472hooks.
2473
2474pyexpat - an interface to the Expat XML parser, contributed by Paul
2475Prescod.
2476
2477xml - a new package with XML support code organized (so far) in three
2478subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2479would fill a volume. There's a special feature whereby a
2480user-installed package named _xmlplus overrides the standard
2481xmlpackage; this is intended to give the XML SIG a hook to distribute
2482backwards-compatible updates to the standard xml package.
2483
2484webbrowser - a platform-independent API to launch a web browser.
2485
2486
Guido van Rossume905e952000-09-05 12:42:46 +00002487Changed Modules
2488---------------
2489
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002490array -- new methods for array objects: count, extend, index, pop, and
2491remove
2492
2493binascii -- new functions b2a_hex and a2b_hex that convert between
2494binary data and its hex representation
2495
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002496calendar -- Many new functions that support features including control
2497over which day of the week is the first day, returning strings instead
2498of printing them. Also new symbolic constants for days of week,
2499e.g. MONDAY, ..., SUNDAY.
2500
2501cgi -- FieldStorage objects have a getvalue method that works like a
2502dictionary's get method and returns the value attribute of the object.
2503
2504ConfigParser -- The parser object has new methods has_option,
2505remove_section, remove_option, set, and write. They allow the module
2506to be used for writing config files as well as reading them.
2507
2508ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002509optionally support the RFC 959 REST command.
2510
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002511gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002512
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002513httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2514the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002515
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002516locale -- implement getdefaultlocale for Win32 and Macintosh
2517
2518marshal -- no longer dumps core when marshaling deeply nested or
2519recursive data structures
2520
2521os -- new functions isatty, seteuid, setegid, setreuid, setregid
2522
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002523os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2524support under Unix.
2525
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002526os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002527
2528os.path -- fix semantics of os.path.commonprefix
2529
2530smtplib -- support for sending very long messages
2531
2532socket -- new function getfqdn()
2533
2534readline -- new functions to read, write and truncate history files.
2535The readline section of the library reference manual contains an
2536example.
2537
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002538select -- add interface to poll system call
2539
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002540shutil -- new copyfileobj function
2541
2542SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2543HTTP server.
2544
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002545Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002546
2547urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002548e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002549
2550whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002551
2552
2553Obsolete Modules
2554----------------
2555
2556None. However note that 1.6 made a whole slew of modules obsolete:
2557stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2558poly, zmod, strop, util, whatsound.
2559
2560
2561Changed, New, Obsolete Tools
2562----------------------------
2563
Tim Peters8b092332000-09-05 20:15:25 +00002564None.
Guido van Rossume905e952000-09-05 12:42:46 +00002565
2566
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002567C-level Changes
2568---------------
2569
2570Several cleanup jobs were carried out throughout the source code.
2571
2572All C code was converted to ANSI C; we got rid of all uses of the
2573Py_PROTO() macro, which makes the header files a lot more readable.
2574
2575Most of the portability hacks were moved to a new header file,
2576pyport.h; several other new header files were added and some old
2577header files were removed, in an attempt to create a more rational set
2578of header files. (Few of these ever need to be included explicitly;
2579they are all included by Python.h.)
2580
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002581Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002582and Win64, especially for the new Intel Itanium processor. Mick also
2583added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002584
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002585The C APIs to return an object's size have been update to consistently
2586use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2587previous versions, the abstract interfaces used PyXXX_Length and the
2588concrete interfaces used PyXXX_Size. The old names,
2589e.g. PyObject_Length, are still available for backwards compatibility
2590at the API level, but are deprecated.
2591
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002592The PyOS_CheckStack function has been implemented on Windows by
2593Fredrik Lundh. It prevents Python from failing with a stack overflow
2594on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002595
2596The GC changes resulted in creation of two new slots on object,
2597tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002598the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002599
2600The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002601C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002602
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002603PyErr_Format has been updated to automatically calculate the size of
2604the buffer needed to hold the formatted result string. This change
2605prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002606
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002607New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002608
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002609PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2610that are the same as their non-Ex counterparts except they take an
2611extra flag argument that tells them to close the file when done.
2612
2613XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002614
Tim Peters8b092332000-09-05 20:15:25 +00002615
2616Windows Changes
2617---------------
2618
2619New popen2/popen3/peopen4 in os module (see Changed Modules above).
2620
2621os.popen is much more usable on Windows 95 and 98. See Microsoft
2622Knowledge Base article Q150956. The Win9x workaround described there
2623is implemented by the new w9xpopen.exe helper in the root of your
2624Python installation. Note that Python uses this internally; it is not
2625a standalone program.
2626
2627Administrator privileges are no longer required to install Python
2628on Windows NT or Windows 2000. If you have administrator privileges,
2629Python's registry info will be written under HKEY_LOCAL_MACHINE.
2630Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002631under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002632uses of Python, but will prevent some advanced uses from working
2633(for example, running a Python script as an NT service, or possibly
2634from CGI).
2635
2636[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2637installer; instead, it installs the needed Tcl/Tk files directly in the
2638Python directory. If you already have a Tcl/Tk installation, this
2639wastes some disk space (about 4 Megs) but avoids problems with
2640conflicting Tcl/Tk installations, and makes it much easier for Python
2641to ensure that Tcl/Tk can find all its files.
2642
2643[This was new in 1.6] The Windows installer now installs by default in
2644\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2645
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002646
2647Updates to the changes between 1.5.2 and 1.6
2648--------------------------------------------
2649
2650The 1.6 NEWS file can't be changed after the release is done, so here
2651is some late-breaking news:
2652
2653New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2654and changes to getlocale() and setlocale().
2655
2656The new module is now enabled per default.
2657
2658It is not true that the encodings codecs cannot be used for normal
2659strings: the string.encode() (which is also present on 8-bit strings
2660!) allows using them for 8-bit strings too, e.g. to convert files from
2661cp1252 (Windows) to latin-1 or vice-versa.
2662
2663Japanese codecs are available from Tamito KAJIYAMA:
2664http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2665
2666
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002667======================================================================