blob: b10f4401cc015aa7cc87e60f17032eed440b79b2 [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
Guido van Rossuma8bcf802001-10-15 15:53:58 +000025- A very subtle syntactical pitfall in list comprehensions was fixed.
26 For example: [a+b for a in 'abc', for b in 'def']. The comma in
27 this example is a mistake. Previously, this would silently let 'a'
28 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
29 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
30 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
31 Note that [a for a in <singleton>] is a convoluted way to say
32 [<singleton>] anyway, so it's not like any expressiveness is lost.
33
Martin v. Löwis16dc7f42001-09-30 20:32:11 +000034- binascii has now two quopri support functions, a2b_qp and b2a_qp.
35
Martin v. Löwis0daad592001-09-30 21:09:59 +000036- readline now supports setting the startup_hook and the pre_event_hook.
37
Martin v. Löwis16628c92001-10-04 22:46:41 +000038- posix supports chroot where available.
39
Tim Petersabf925f2001-09-28 21:53:42 +000040Library
41
Tim Peters7402f792001-10-02 03:53:41 +000042- doctest now excludes functions and classes not defined by the module
43 being tested, thanks to Tim Hochberg.
44
Guido van Rossumc4b09b42001-10-04 10:19:00 +000045- profile now produces correct output in situations where an exception
46 raised in Python is cleared by C code (e.g. hasattr()). This used
47 to cause wrong output, including spurious claims of recursive
48 functions and attribution of time spent to the wrong function.
49
Tim Peters0a1fc4e2001-10-07 03:12:08 +000050 The code and documentation for the derived OldProfile and HotProfile
51 profiling classes was removed. The code hasn't worked for years (if
52 you tried to use them, they raised exceptions). OldProfile
53 intended to reproduce the behavior of the profiler Python used more
54 than 7 years ago, and isn't interesting anymore. HotProfile intended
55 to provide a faster profiler (but producing less information), and
56 that's a worthy goal we intend to meet via a different approach (but
57 without losing information).
58
Tim Peterscce092d2001-10-09 05:31:56 +000059- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +000060 a much better system-specific calibration constant. The constant can
61 now be specified in an instance constructor, or as a Profile class or
62 instance variable, instead of by editing profile.py's source code.
63 Calibration must still be done manually (see the docs for the profile
64 module).
65
66 Note that Profile.calibrate() must be overriden by subclasses.
67 Improving the accuracy required exploiting detailed knowledge of
68 profiler internals; the earlier method abstracted away the details
69 and measured a simplified model instead, but consequently computed
70 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +000071
Martin v. Löwis16dc7f42001-09-30 20:32:11 +000072- quopri's encode and decode methods take an optional header parameter,
73 which indicates whether output is intended for the header 'Q' encoding.
74
Guido van Rossumed554f62001-10-02 23:15:37 +000075Tools/Demos
76
77- Demo/dns was removed. It no longer serves any purpose; a package
78 derived from it is now maintained by Anthony Baxter, see
79 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +000080
81Build
82
83C API
84
Tim Petersd38b1c72001-09-30 05:09:37 +000085- PyLong_AsLongLong() now accepts int (as well as long) arguments.
86 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
87 as long) arguments.
88
Tim Petersabf925f2001-09-28 21:53:42 +000089New platforms
90
91Tests
92
93Windows
94
Tim Peters04cf1d32001-10-09 22:39:40 +000095- Installer: If you install IDLE, and don't disable file-extension
96 registration, a new "Edit with IDLE" context (right-click) menu entry
97 is created for .py and .pyw files.
98
Tim Peters1ce3cf72001-10-01 17:58:40 +000099- The signal module now supports SIGBREAK on Windows, thanks to Steven
100 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
101 action remains to call Win32 ExitProcess(). This can be changed via
102 signal.signal(). For example:
103
104 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
105 # (SIGINT) behavior.
106 import signal
107 signal.signal(signal.SIGBREAK,
108 signal.default_int_handler)
109
110 try:
111 while 1:
112 pass
113 except KeyboardInterrupt:
114 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
115 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
116 # program without the possibility for any Python-level cleanup).
117 print "Clean exit"
118
Tim Petersabf925f2001-09-28 21:53:42 +0000119
Tim Petersb07352e2001-09-08 01:25:47 +0000120What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000121Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000122===========================
123
Guido van Rossum808eea72001-09-25 04:15:41 +0000124Type/class unification and new-style classes
125
126- pydoc and inspect are now aware of new-style classes;
127 e.g. help(list) at the interactive prompt now shows proper
128 documentation for all operations on list objects.
129
130- Applications using Jim Fulton's ExtensionClass module can now safely
131 be used with Python 2.2. In particular, Zope 2.4.1 now works with
132 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
133 examples also work again. It is hoped that Gtk and Boost also work
134 with 2.2a4 and beyond. (If you can confirm this, please write
135 webmaster@python.org; if there are still problems, please open a bug
136 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000137
Tim Peters66c1a522001-09-24 21:17:50 +0000138- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
139 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
140 in the constructed property object. fget, fset and fdel weren't
141 discoverable from Python in 2.2a3. __doc__ is new, and allows to
142 associate a docstring with a property.
143
Guido van Rossum808eea72001-09-25 04:15:41 +0000144- Comparison overloading is now more completely implemented. For
145 example, a str subclass instance can properly be compared to a str
146 instance, and it can properly overload comparison. Ditto for most
147 other built-in object types.
148
149- The repr() of new-style classes has changed; instead of <type
150 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
151 *except* for built-in types, which are still rendered as <type
152 'Foo'> (to avoid upsetting existing code that might parse or
153 otherwise rely on repr() of certain type objects).
154
155- The repr() of new-style objects is now always <Foo object at XXX>;
156 previously, it was sometimes <Foo instance at XXX>.
157
158- For new-style classes, what was previously called __getattr__ is now
159 called __getattribute__. This method, if defined, is called for
160 *every* attribute access. A new __getattr__ hook mor similar to the
161 one in classic classes is defined which is called only if regular
162 attribute access raises AttributeError; to catch *all* attribute
163 access, you can use __getattribute__ (for new-style classes). If
164 both are defined, __getattribute__ is called first, and if it raises
165 AttributeError, __getattr__ is called.
166
167- The __class__ attribute of new-style objects can be assigned to.
168 The new class must have the same C-level object layout as the old
169 class.
170
171- The builtin file type can be subclassed now. In the usual pattern,
172 "file" is the name of the builtin type, and file() is a new builtin
173 constructor, with the same signature as the builtin open() function.
174 file() is now the preferred way to open a file.
175
176- Previously, __new__ would only see sequential arguments passed to
177 the type in a constructor call; __init__ would see both sequential
178 and keyword arguments. This made no sense whatsoever any more, so
179 now both __new__ and __init__ see all arguments.
180
181- Previously, hash() applied to an instance of a subclass of str or
182 unicode always returned 0. This has been repaired.
183
184- Previously, an operation on an instance of a subclass of an
185 immutable type (int, long, float, complex, tuple, str, unicode),
186 where the subtype didn't override the operation (and so the
187 operation was handled by the builtin type), could return that
188 instance instead a value of the base type. For example, if s was of
189 a str sublass type, s[:] returned s as-is. Now it returns a str
190 with the same value as s.
191
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000192- Provisional support for pickling new-style objects has been added.
193
Guido van Rossum808eea72001-09-25 04:15:41 +0000194Core
195
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000196- file.writelines() now accepts any iterable object producing strings.
197
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000198- PyUnicode_FromEncodedObject() now works very much like
199 PyObject_Str(obj) in that it tries to use __str__/tp_str
200 on the object if the object is not a string or buffer. This
201 makes unicode() behave like str() when applied to non-string/buffer
202 objects.
203
Martin v. Löwis2777c022001-09-19 13:47:32 +0000204- PyFile_WriteObject now passes Unicode object to the file's write
205 method. As a result, all file-like object which may be the target
206 of a print statement must support Unicode objects, i.e. they must
207 at least convert them into ASCII strings.
208
Guido van Rossum624c8af2001-09-18 15:21:04 +0000209- Thread scheduling on Solaris should be improved; it is no longer
210 necessary to insert a small sleep at the start of a thread in order
211 to let other runnable threads be scheduled.
212
Tim Petersb07352e2001-09-08 01:25:47 +0000213Library
214
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000215- StringIO.StringIO instances and cStringIO.StringIO instances support
216 read character buffer compatible objects for their .write() methods.
217 These objects are converted to strings and then handled as such
218 by the instances.
219
Barry Warsaw2f600732001-09-24 04:28:10 +0000220- The "email" package has been added. This is basically a port of the
221 mimelib package <http://sf.net/projects/mimelib> with API changes
222 and some implementations updated to use iterators and generators.
223
Tim Peters8a9c2842001-09-22 21:30:22 +0000224- difflib.ndiff() and difflib.Differ.compare() are generators now. This
225 restores the ability of Tools/scripts/ndiff.py to start producing output
226 before the entire comparison is complete.
227
Barry Warsaw58b072d2001-09-22 04:44:21 +0000228- StringIO.StringIO instances and cStringIO.StringIO instances support
229 iteration just like file objects (i.e. their .readline() method is
230 called for each iteration until it returns an empty string).
231
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000232- The codecs module has grown four new helper APIs to access
233 builtin codecs: getencoder(), getdecoder(), getreader(),
234 getwriter().
235
Guido van Rossum624c8af2001-09-18 15:21:04 +0000236- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
237 simplifies writing XML RPC servers.
238
Barry Warsaw647d5e82001-09-28 17:01:02 +0000239- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000240 after interpretation of symbolic links. On non-Unix systems, this
241 is an alias for os.path.abspath().
242
Tim Peters16a77ad2001-09-08 04:00:12 +0000243- operator.indexOf() (PySequence_Index() in the C API) now works with any
244 iterable object.
245
Guido van Rossum624c8af2001-09-18 15:21:04 +0000246- smtplib now supports various authentication and security features of
247 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000248
Guido van Rossum624c8af2001-09-18 15:21:04 +0000249- hmac: a new module implementing keyed hashing for message
250 authentication.
251
252- mimetypes now recognizes more extensions and file types. At the
253 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000254
Guido van Rossum624c8af2001-09-18 15:21:04 +0000255- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000256 Python 2.2 bytecode generation. It has also been promoted from a
257 Tool to a standard library package. (Tools/compiler still exists as
258 a sample driver.)
259
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000260Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000261
Tim Petersb07352e2001-09-08 01:25:47 +0000262Build
263
Guido van Rossum624c8af2001-09-18 15:21:04 +0000264- Large file support (LFS) is now automatic when the platform supports
265 it; no more manual configuration tweaks are needed. On Linux, at
266 least, it's possible to have a system whose C library supports large
267 files but whose kernel doesn't; in this case, large file support is
268 still enabled but doesn't do you any good unless you upgrade your
269 kernel or share your Python executable with another system whose
270 kernel has large file support.
271
272- The configure script now supplies plausible defaults in a
273 cross-compilation environment. This doesn't mean that the supplied
274 values are always correct, or that cross-compilation now works
275 flawlessly -- but it's a first step (and it shuts up most of
276 autoconf's warnings about AC_TRY_RUN).
277
278- The Unix build is now a bit less chatty, courtesy of the parser
279 generator. The build is completely silent (except for errors) when
280 using "make -s", thanks to a -q option to setup.py.
281
Tim Petersb07352e2001-09-08 01:25:47 +0000282C API
283
Guido van Rossum624c8af2001-09-18 15:21:04 +0000284- The "structmember" API now supports some new flag bits to deny read
285 and/or write access to attributes in restricted execution mode.
286
Tim Petersb07352e2001-09-08 01:25:47 +0000287New platforms
288
Guido van Rossum624c8af2001-09-18 15:21:04 +0000289- Compaq's iPAQ handheld, running the "familiar" Linux distribution
290 (http://familiar.handhelds.org).
291
Tim Petersb07352e2001-09-08 01:25:47 +0000292Tests
293
Tim Peters8a9c2842001-09-22 21:30:22 +0000294- The "classic" standard tests, which work by comparing stdout to
295 an expected-output file under Lib/test/output/, no longer stop at
296 the first mismatch. Instead the test is run to completion, and a
297 variant of ndiff-style comparison is used to report all differences.
298 This is much easier to understand than the previous style of reporting.
299
300- The unittest-based standard tests now use regrtest's test_main()
301 convention, instead of running as a side-effect of merely being
302 imported. This allows these tests to be run in more natural and
303 flexible ways as unittests, outside the regrtest framework.
304
305- regrtest.py is much better integrated with unittest and doctest now,
306 especially in regard to reporting errors.
307
Tim Petersb07352e2001-09-08 01:25:47 +0000308Windows
309
Guido van Rossum624c8af2001-09-18 15:21:04 +0000310- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000311 that support it (NTFS under Windows 2000). See "What's New in
312 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000313
Tim Petersb07352e2001-09-08 01:25:47 +0000314
Tim Petersedc99312001-08-22 21:36:50 +0000315What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000316Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000317===========================
318
319Core
320
Tim Peters9fffa3e2001-09-04 05:14:19 +0000321- Conversion of long to float now raises OverflowError if the long is too
322 big to represent as a C double.
323
Tim Peters32f453e2001-09-03 08:35:41 +0000324- The 3-argument builtin pow() no longer allows a third non-None argument
325 if either of the first two arguments is a float, or if both are of
326 integer types and the second argument is negative (in which latter case
327 the arguments are converted to float, so this is really the same
328 restriction).
329
Tim Peters5d2b77c2001-09-03 05:47:38 +0000330- The builtin dir() now returns more information, and sometimes much
331 more, generally naming all attributes of an object, and all attributes
332 reachable from the object via its class, and from its class's base
333 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
334 an empty list. In 2.2a3,
335
336 >>> dir([])
337 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
338 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
339 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
340 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
341 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
342 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
343 'reverse', 'sort']
344
345 dir(module) continues to return only the module's attributes, though.
346
Tim Petersbdee63f2001-09-02 03:40:59 +0000347- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000348 than raising OverflowError. This is a partial implementation of PEP
349 237. You can use -Wdefault::OverflowWarning to enable a warning for
350 this situation, and -Werror::OverflowWarning to revert to the old
351 OverflowError exception.
352
Guido van Rossum61c345f2001-09-04 03:26:15 +0000353- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000354 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000355 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
356 -Qold, meaning the / operator has its classic meaning and no
357 warnings are issued. Using -Qwarn issues a run-time warning about
358 all uses of classic division for int and long arguments; -Qwarnall
359 also warns about classic division for float and complex arguments
360 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
361 new division by default, but only in the __main__ module. You can
362 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
363 __main__ module new division, and warns about classic division
364 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000365
Tim Petersbdee63f2001-09-02 03:40:59 +0000366- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000367 long, float, str, unicode, and tuple. (The types complex, list and
368 dictionary can also be subclassed; this was introduced earlier.)
369 Note that restrictions apply when subclassing immutable built-in
370 types: you can only affect the value of the instance by overloading
371 __new__. You can add mutable attributes, and the subclass instances
372 will have a __dict__ attribute, but you cannot change the "value"
373 (as implemented by the base class) of an immutable subclass instance
374 once it is created.
375
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000376- The dictionary constructor now takes an optional argument, a
377 mapping-like object, and initializes the dictionary from its
378 (key, value) pairs.
379
Tim Petersbdee63f2001-09-02 03:40:59 +0000380- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000381 "cooperative super calls" in a multiple inheritance setting. For an
382 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
383
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000384- A new built-in type, property, has been added. This enables the
385 creation of "properties". These are attributes implemented by
386 getter and setter functions (or only one of these for read-only or
387 write-only attributes), without the need to override __getattr__.
388 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000389
Tim Petersbdee63f2001-09-02 03:40:59 +0000390- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000391 liberalized, to allow leading zeroes. Examples of literals now
392 legal that were SyntaxErrors before:
393
394 00.0 0e3 0100j 07.5 00000000000000000008.
395
Tim Petersbdee63f2001-09-02 03:40:59 +0000396- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000397 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
398
Tim Petersedc99312001-08-22 21:36:50 +0000399Library
400
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000401- telnetlib includes symbolic names for the options, and support for
402 setting an option negotiation callback.
403
Tim Petersa40c7932001-09-05 22:36:56 +0000404- The new C standard no longer requires that math libraries set errno to
405 ERANGE on overflow. For platform libraries that exploit this new
406 freedom, Python's overflow-checking was wholly broken. A new overflow-
407 checking scheme attempts to repair that, but may not be reliable on all
408 platforms (C doesn't seem to provide anything both useful and portable
409 in this area anymore).
410
Martin v. Löwis44f86962001-09-05 13:44:54 +0000411- Asynchronous timeout actions are available through the new class
412 threading.Timer.
413
Tim Peters78526162001-09-05 00:53:45 +0000414- math.log and math.log10 now return sensible results for even huge
415 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
416
Tim Petersbdee63f2001-09-02 03:40:59 +0000417- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000418 currently held. See the docs for the imp module.
419
Tim Petersbdee63f2001-09-02 03:40:59 +0000420- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000421 dumps containing ints written on platforms where Python ints are 8 bytes.
422 When read on a box where Python ints are 4 bytes, such values are
423 converted to Python longs.
424
Tim Petersbdee63f2001-09-02 03:40:59 +0000425- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000426 code objects is no longer allowed. This plugs a security hole.
427
Steve Purcell6091cd62001-09-06 16:05:17 +0000428- unittest.TestResult instances no longer store references to tracebacks
429 generated by test failures. This prevents unexpected dangling references
430 to objects that should be garbage collected between tests.
431
Tim Petersedc99312001-08-22 21:36:50 +0000432Tools
433
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000434- Tools/scripts/fixdiv.py has been added which can be used to fix
435 division operators as per PEP 238.
436
Tim Petersedc99312001-08-22 21:36:50 +0000437Build
438
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000439- If you are an adventurous person using Mac OS X you may want to look at
440 Mac/OSX. There is a Makefile there that will build Python as a real Mac
441 application, which can be used for experimenting with Carbon or Cocoa.
442 Discussion of this on pythonmac-sig, please.
443
Tim Peters7eea37e2001-09-04 22:08:56 +0000444C API
445
446- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000447
Tim Peters9fffa3e2001-09-04 05:14:19 +0000448- Note that PyLong_AsDouble can fail! This has always been true, but no
449 callers checked for it. It's more likely to fail now, because overflow
450 errors are properly detected now. The proper way to check:
451
452 double x = PyLong_AsDouble(some_long_object);
453 if (x == -1.0 && PyErr_Occurred()) {
454 /* The conversion failed. */
455 }
456
Tim Petersbdee63f2001-09-02 03:40:59 +0000457- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000458 compile but will not participate in GC. To upgrade an extension
459 module:
460
461 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000462
Neil Schemenauer4042c692001-08-30 15:38:01 +0000463 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
464 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000465
Neil Schemenauer4042c692001-08-30 15:38:01 +0000466 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
467 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000468
Neil Schemenauer4042c692001-08-30 15:38:01 +0000469 - remove PyGC_HEAD_SIZE from object size calculations
470
471 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
472
Tim Petersbdee63f2001-09-02 03:40:59 +0000473- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000474 These can be used safely to construct string objects from a
475 sprintf-style format string (similar to the format string supported
476 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000477
Tim Petersedc99312001-08-22 21:36:50 +0000478New platforms
479
Tim Petersb7da0902001-09-02 23:01:43 +0000480- Stephen Hansen contributed patches sufficient to get a clean compile
481 under Borland C (Windows), but he reports problems running it and ran
482 out of time to complete the port. Volunteers? Expect a MemoryError
483 when importing the types module; this is probably shallow, and
484 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000485
Tim Petersedc99312001-08-22 21:36:50 +0000486Tests
487
488Windows
489
Tim Peters6e13a562001-09-06 00:32:15 +0000490- Large file support is now enabled on Win32 platforms as well as on
491 Win64. This means that, for example, you can use f.tell() and f.seek()
492 to manipulate files larger than 2 gigabytes (provided you have enough
493 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000494 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
495 filesize limit, and large file support makes no difference there.
496 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
497 NTFS has no practical limit on file size, and files of any size can be
498 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000499
Tim Petersbdee63f2001-09-02 03:40:59 +0000500- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000501 points to command.com (patch from Brian Quinlan).
502
Tim Petersedc99312001-08-22 21:36:50 +0000503
Tim Peters20f51a72001-07-21 02:31:40 +0000504What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000505Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000506===========================
507
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000508Build
509
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000510- Tim Peters developed a brand new Windows installer using Wise 8.1,
511 generously donated to us by Wise Solutions.
512
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000513- configure supports a new option --enable-unicode, with the values
514 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
515 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000516
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000517- A new configure option --enable-framework builds a Mac OS X framework,
518 which "make frameworkinstall" will install. This provides a starting
519 point for more mac-like functionality, join pythonmac-sig@python.org
520 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000521
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000522- The NeXT platform is no longer supported.
523
524- The `new' module is now statically linked.
525
Tim Peters0afb6092001-08-15 06:06:44 +0000526Tools
527
528- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000529 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000530 the module docstring for details.
531
Tim Peters20f51a72001-07-21 02:31:40 +0000532Tests
533
Tim Peters5e824c32001-08-12 22:25:01 +0000534- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000535 platforms, allowing to give clearer test result output. regrtest
536 also has optional --use/-u switch to run normally disabled tests
537 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000538
Tim Peters20f51a72001-07-21 02:31:40 +0000539- Several new tests in the standard test suite, with special thanks to
540 Nick Mathewson.
541
542Core
543
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000544- The floor division operator // has been added as outlined in PEP
545 238. The / operator still provides classic division (and will until
546 Python 3.0) unless "from __future__ import division" is included, in
547 which case the / operator will provide true division. The operator
548 module provides truediv() and floordiv() functions. Augmented
549 assignment variants are included, as are the equivalent overloadable
550 methods and C API methods. See the PEP for a full discussion:
551 <http://python.sf.net/peps/pep-0238.html>
552
Tim Peters6cd6a822001-08-17 22:11:27 +0000553- Future statements are now effective in simulated interactive shells
554 (like IDLE). This should "just work" by magic, but read Michael
555 Hudson's "Future statements in simulated shells" PEP 264 for full
556 details: <http://python.sf.net/peps/pep-0264.html>.
557
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000558- The type/class unification (PEP 252-253) was integrated into the
559 trunk and is not so tentative any more (the exact specification of
560 some features is still tentative). A lot of work has done on fixing
561 bugs and adding robustness and features (performance still has to
562 come a long way).
563
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000564- Warnings about a mismatch in the Python API during extension import
565 now use the Python warning framework (which makes it possible to
566 write filters for these warnings).
567
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000568- A function's __dict__ (aka func_dict) will now always be a
569 dictionary. It used to be possible to delete it or set it to None,
570 but now both actions raise TypeErrors. It is still legal to set it
571 to a dictionary object. Getting func.__dict__ before any attributes
572 have been assigned now returns an empty dictionary instead of None.
573
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000574- A new command line option, -E, was added which disables the use of
575 all environment variables, or at least those that are specifically
576 significant to Python. Usually those have a name starting with
577 "PYTHON". This was used to fix a problem where the tests fail if
578 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
579 older distribution.
580
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000581Library
582
Tim Peters5e824c32001-08-12 22:25:01 +0000583- New class Differ and new functions ndiff() and restore() in difflib.py.
584 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000585 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000586
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000587- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
588 value using the minimal quoting required for the value; more
589 reliable than using xml.sax.saxutils.escape() for attribute values.
590
591- Readline completion support for cmd.Cmd was added.
592
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000593- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
594
595- Added function threading.BoundedSemaphore()
596
597- Added Ka-Ping Yee's cgitb.py module.
598
599- The `new' module now exposes the CO_xxx flags.
600
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000601New platforms
602
603C API
604
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000605- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
606 which provide a cross-platform implementations for the
607 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
608 the standard sprintf() and vsprintf() C lib APIs, these versions
609 apply bounds checking on the used buffer which enhances protection
610 against buffer overruns.
611
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000612- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000613 and extensions using different Unicode widths is rendered next to
614 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000615 will result in an ImportError. Unicode extensions writers must make
616 sure to check the Unicode width compatibility in their extensions by
617 using at least one of the mangled Unicode APIs in the extension.
618
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000619- Two new flags METH_NOARGS and METH_O are available in method definition
620 tables to simplify implementation of methods with no arguments and a
621 single untyped argument. Calling such methods is more efficient than
622 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
623 deprecated.
624
Tim Petersc1731372001-08-04 08:12:36 +0000625Windows
626
627- "import module" now compiles module.pyw if it exists and nothing else
628 relevant is found.
629
Tim Peters20f51a72001-07-21 02:31:40 +0000630
Guido van Rossum55a78992001-07-17 17:22:32 +0000631What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +0000632===========================
633
634Core
Tim Petersa814db52001-05-14 07:05:58 +0000635
Tim Peters6d6c1a32001-08-02 04:15:00 +0000636- TENTATIVELY, a large amount of code implementing much of what's
637 described in PEP 252 (Making Types Look More Like Classes) and PEP
638 253 (Subtyping Built-in Types) was added. This will be released
639 with Python 2.2a1. Documentation will be provided separately
640 through http://www.python.org/2.2/. The purpose of releasing this
641 with Python 2.2a1 is to test backwards compatibility. It is
642 possible, though not likely, that a decision is made not to release
643 this code as part of 2.2 final, if any serious backwards
644 incompapatibilities are found during alpha testing that cannot be
645 repaired.
646
Guido van Rossum55a78992001-07-17 17:22:32 +0000647- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000648 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000649 more 'yield' statements. See PEP 255. Since this adds a new
650 keyword to the language, this feature must be enabled by including a
651 future statement: "from __future__ import generators" (see PEP 236).
652 Generators will become a standard feature in a future release
653 (probably 2.3). Without this future statement, 'yield' remains an
654 ordinary identifier, but a warning is issued each time it is used.
655 (These warnings currently don't conform to the warnings framework of
656 PEP 230; we intend to fix this in 2.2a2.)
657
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000658- The UTF-16 codec was modified to be more RFC compliant. It will now
659 only remove BOM characters at the start of the string and then
660 only if running in native mode (UTF-16-LE and -BE won't remove a
661 leading BMO character).
662
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000663- Strings now have a new method .decode() to complement the already
664 existing .encode() method. These two methods provide direct access
665 to the corresponding decoders and encoders of the registered codecs.
666
667 To enhance the usability of the .encode() method, the special
668 casing of Unicode object return values was dropped (Unicode objects
669 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000670
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000671 Both methods will now return whatever the codec in charge of the
672 requested encoding returns as object, e.g. Unicode codecs will
673 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
674 will return u"äöü"). This enables codec writer to create codecs
675 for various simple to use conversions.
676
677 New codecs were added to demonstrate these new features (the .encode()
678 and .decode() columns indicate the type of the returned objects):
679
680 Name | .encode() | .decode() | Description
681 ----------------------------------------------------------------------
682 uu | string | string | UU codec (e.g. for email)
683 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000684 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000685 zlib | string | string | zlib compression
686 hex | string | string | 2-byte hex codec
687 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
688
Mark Hammond2a0af792001-05-14 03:09:36 +0000689- Some operating systems now support the concept of a default Unicode
690 encoding for file system operations. Notably, Windows supports 'mbcs'
691 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000692 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000693 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000694
695 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000696 functions that return filenames (such as os.listdir()) to return Python
697 string objects pre-encoded using the default file system encoding for
698 the platform. As this encoding is likely to be different from Python's
699 default encoding, converting this name to a Unicode object before passing
700 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000701 would attempt to use its default encoding (generally ASCII) rather than
702 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000703
Tim Petersa814db52001-05-14 07:05:58 +0000704 In general, this change simply removes surprises when working with
705 Unicode and the file system, making these operations work as you expect,
706 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000707 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000708
Tim Peters61dff2b2001-05-08 15:43:37 +0000709- Float (and complex) literals in source code were evaluated to full
710 precision only when running from a .py file; the same code loaded from a
711 .pyc (or .pyo) file could suffer numeric differences starting at about the
712 12th significant decimal digit. For example, on a machine with IEEE-754
713 floating arithmetic,
714
715 x = 9007199254740992.0
716 print long(x)
717
718 printed 9007199254740992 if run directly from .py, but 9007199254740000
719 if from a compiled (.pyc or .pyo) file. This was due to marshal using
720 str(float) instead of repr(float) when building code objects. marshal
721 now uses repr(float) instead, which should reproduce floats to full
722 machine precision (assuming the platform C float<->string I/O conversion
723 functions are of good quality).
724
725 This may cause floating-point results to change in some cases, and
726 usually for the better, but may also cause numerically unstable
727 algorithms to break.
728
Tim Peters2f228e72001-05-13 00:19:31 +0000729- The implementation of dicts suffers fewer collisions, which has speed
730 benefits. However, the order in which dict entries appear in dict.keys(),
731 dict.values() and dict.items() may differ from previous releases for a
732 given dict. Nothing is defined about this order, so no program should
733 rely on it. Nevertheless, it's easy to write test cases that rely on the
734 order by accident, typically because of printing the str() or repr() of a
735 dict to an "expected results" file. See Lib/test/test_support.py's new
736 sortdict(dict) function for a simple way to display a dict in sorted
737 order.
738
Tim Peters7a3bfc32001-06-12 01:22:22 +0000739- Many other small changes to dicts were made, resulting in faster
740 operation along the most common code paths.
741
Guido van Rossum10315822001-05-01 20:54:30 +0000742- Dictionary objects now support the "in" operator: "x in dict" means
743 the same as dict.has_key(x).
744
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000745- The update() method of dictionaries now accepts generic mapping
746 objects. Specifically the argument object must support the .keys()
747 and __getitem__() methods. This allows you to say, for example,
748 {}.update(UserDict())
749
Guido van Rossum10315822001-05-01 20:54:30 +0000750- Iterators were added; this is a generalized way of providing values
751 to a for loop. See PEP 234. There's a new built-in function iter()
752 to return an iterator. There's a new protocol to get the next value
753 from an iterator using the next() method (in Python) or the
754 tp_iternext slot (in C). There's a new protocol to get iterators
755 using the __iter__() method (in Python) or the tp_iter slot (in C).
756 Iterating (i.e. a for loop) over a dictionary generates its keys.
757 Iterating over a file generates its lines.
758
Tim Petersf553f892001-05-01 20:45:31 +0000759- The following functions were generalized to work nicely with iterator
760 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000761 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000762 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
763 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000764 join() method of strings
765 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000766 'x in y' and 'x not in y' (PySequence_Contains() in C API)
767 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000768 right-hand side of assignment statements with multiple targets, such as
769 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000770
Tim Petersd85e1022001-05-11 21:51:48 +0000771- Accessing module attributes is significantly faster (for example,
772 random.random or os.path or yourPythonModule.yourAttribute).
773
Tim Peterse63415e2001-05-08 04:38:29 +0000774- Comparing dictionary objects via == and != is faster, and now works even
775 if the keys and values don't support comparisons other than ==.
776
Tim Peters95bf9392001-05-10 08:32:44 +0000777- Comparing dictionaries in ways other than == and != is slower: there were
778 insecurities in the dict comparison implementation that could cause Python
779 to crash if the element comparison routines for the dict keys and/or
780 values mutated the dicts. Making the code bulletproof slowed it down.
781
Tim Peterseb28ef22001-06-02 05:27:19 +0000782- Collisions in dicts are resolved via a new approach, which can help
783 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000784 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000785 faster now. Thanks to Christian Tismer for pointing out the cause and
786 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000787
Tim Peters52e155e2001-06-16 05:42:57 +0000788- repr() is much faster for large containers (dict, list, tuple).
789
790
Tim Petersa814db52001-05-14 07:05:58 +0000791Library
792
Fred Drake960fdf92001-07-20 18:38:26 +0000793- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
794 were added to the string module. These a locale-indenpendent
795 constants, unlike letters, lowercase, and uppercase. These are now
796 use in appropriate locations in the standard library.
797
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000798- The flags used in dlopen calls can now be configured using
799 sys.setdlopenflags and queried using sys.getdlopenflags.
800
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000801- Fredrik Lundh's xmlrpclib is now a standard library module. This
802 provides full client-side XML-RPC support. In addition,
803 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
804 one asyncore-based). Thanks to Eric Raymond for the documentation.
805
Guido van Rossum643d3912001-07-05 14:46:25 +0000806- The xrange() object is simplified: it no longer supports slicing,
807 repetition, comparisons, efficient 'in' checking, the tolist()
808 method, or the start, stop and step attributes. See PEP 260.
809
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000810- A new function fnmatch.filter to filter lists of file names was added.
811
Barry Warsawffd674d2001-05-22 16:00:10 +0000812- calendar.py uses month and day names based on the current locale.
813
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000814- strop is now *really* obsolete (this was announced before with 1.6),
815 and issues DeprecationWarning when used (except for the four items
816 that are still imported into string.py).
817
Tim Petersa814db52001-05-14 07:05:58 +0000818- Cookie.py now sorts key+value pairs by key in output strings.
819
820- pprint.isrecursive(object) didn't correctly identify recursive objects.
821 Now it does.
822
Tim Peters95b3f782001-05-14 18:39:41 +0000823- pprint functions now much faster for large containers (tuple, list, dict).
824
Tim Peters7b9542a2001-06-10 23:40:19 +0000825- New 'q' and 'Q' format codes in the struct module, corresponding to C
826 types "long long" and "unsigned long long" (on Windows, __int64). In
827 native mode, these can be used only when the platform C compiler supports
828 these types (when HAVE_LONG_LONG is #define'd by the Python config
829 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000830 In standard mode, 'q' and 'Q' are supported on all platforms, and are
831 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000832
Guido van Rossum83213cc2001-06-12 16:48:52 +0000833- The site module installs a new built-in function 'help' that invokes
834 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
835 it displays a message reminding the user to use 'help()' or
836 'help(object)'.
837
Tim Petersa814db52001-05-14 07:05:58 +0000838Tests
839
840- New test_mutants.py runs dict comparisons where the key and value
841 comparison operators mutute the dicts randomly during comparison. This
842 rapidly causes Python to crash under earlier releases (not for the faint
843 of heart: it can also cause Win9x to freeze or reboot!).
844
845- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000846 pprint.isreadable() return sensible results. Also verifies that simple
847 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000848
Tim Peters4324aa32001-05-28 22:30:08 +0000849C API
850
851- Removed the unused last_is_sticky argument from the internal
852 _PyTuple_Resize(). If this affects you, you were cheating.
853
854
Guido van Rossum55a78992001-07-17 17:22:32 +0000855======================================================================
856
857
Guido van Rossumffe13be2001-04-16 18:46:45 +0000858What's New in Python 2.1 (final)?
859=================================
860
861We only changed a few things since the last release candidate, all in
862Python library code:
863
864- A bug in the locale module was fixed that affected locales which
865 define no grouping for numeric formatting.
866
867- A few bugs in the weakref module's implementations of weak
868 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
869 and the test suite was updated to check for these bugs.
870
871- An old bug in the os.path.walk() function (introduced in Python
872 2.0!) was fixed: a non-existent file would cause an exception
873 instead of being ignored.
874
875- Fixed a few bugs in the new symtable module found by Neil Norwitz's
876 PyChecker.
877
878
Guido van Rossum5b08f132001-04-16 02:05:23 +0000879What's New in Python 2.1c2?
880===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000881
Guido van Rossum5b08f132001-04-16 02:05:23 +0000882A flurry of small changes, and one showstopper fixed in the nick of
883time made it necessary to release another release candidate. The list
884here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000885
Guido van Rossum5b08f132001-04-16 02:05:23 +0000886Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000887
Guido van Rossum5b08f132001-04-16 02:05:23 +0000888- Tim discovered a nasty bug in the dictionary code, caused by
889 PyDict_Next() calling dict_resize(), and the GC code's use of
890 PyDict_Next() violating an assumption in dict_items(). This was
891 fixed with considerable amounts of band-aid, but the net effect is a
892 saner and more robust implementation.
893
894- Made a bunch of symbols static that were accidentally global.
895
896Build and Ports
897
898- The setup.py script didn't check for a new enough version of zlib
899 (1.1.3 is needed). Now it does.
900
901- Changed "make clean" target to also remove shared libraries.
902
903- Added a more general warning about the SGI Irix optimizer to README.
904
905Library
906
907- Fix a bug in urllib.basejoin("http://host", "../file.html") which
908 omitted the slash between host and file.html.
909
910- The mailbox module's _Mailbox class contained a completely broken
911 and undocumented seek() method. Ripped it out.
912
913- Fixed a bunch of typos in various library modules (urllib2, smtpd,
914 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
915
916- Fixed a few last-minute bugs in unittest.
917
918Extensions
919
920- Reverted the patch to the OpenSSL code in socketmodule.c to support
921 RAND_status() and the EGD, and the subsequent patch that tried to
922 fix it for pre-0.9.5 versions; the problem with the patch is that on
923 some systems it issues a warning whenever socket is imported, and
924 that's unacceptable.
925
926Tests
927
928- Fixed the pickle tests to work with "import test.test_pickle".
929
930- Tweaked test_locale.py to actually run the test Windows.
931
932- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
933 not "wb" (which is not a valid mode at all).
934
935- Fix pstats browser crashes. Import readline if it exists to make
936 the user interface nicer.
937
938- Add "import thread" to the top of test modules that import the
939 threading module (test_asynchat and test_threadedtempfile). This
940 prevents test failures caused by a broken threading module resulting
941 from a previously caught failed import.
942
943- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
944 needed on some platforms (e.g. Solaris 8) when the tests are run
945 twice in succession.
946
947- Skip rather than fail test_sunaudiodev if no audio device is found.
948
949
950What's New in Python 2.1c1?
951===========================
952
953This list was significantly updated when 2.1c2 was released; the 2.1c1
954release didn't mention most changes that were actually part of 2.1c1:
955
956Legal
957
958- Copyright was assigned to the Python Software Foundation (PSF) and a
959 PSF license (very similar to the CNRI license) was added.
960
961- The CNRI copyright notice was updated to include 2001.
962
963Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000964
Guido van Rossumc9932722001-04-12 02:31:27 +0000965- After a public outcry, assignment to __debug__ is no longer illegal;
966 instead, a warning is issued. It will become illegal in 2.2.
967
Guido van Rossum5b08f132001-04-16 02:05:23 +0000968- Fixed a core dump with "%#x" % 0, and changed the semantics so that
969 "%#x" now always prepends "0x", even if the value is zero.
970
971- Fixed some nits in the bytecode compiler.
972
973- Fixed core dumps when calling certain kinds of non-functions.
974
975- Fixed various core dumps caused by reference count bugs.
976
977Build and Ports
978
979- Use INSTALL_SCRIPT to install script files.
980
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000981- New port: SCO Unixware 7, by Billy G. Allie.
982
Guido van Rossum5b08f132001-04-16 02:05:23 +0000983- Updated RISCOS port.
984
985- Updated BeOS port and notes.
986
987- Various other porting problems resolved.
988
989Library
990
991- The TERMIOS and SOCKET modules are now truly obsolete and
992 unnecessary. Their symbols are incorporated in the termios and
993 socket modules.
994
995- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
996 better tests for pickling.
997
998- threading: make Condition.wait() robust against KeyboardInterrupt.
999
1000- zipfile: add support to zipfile to support opening an archive
1001 represented by an open file rather than a file name. Fix bug where
1002 the archive was not properly closed. Fixed a bug in this bugfix
1003 where flush() was called for a read-only file.
1004
1005- imputil: added an uninstall() method to the ImportManager.
1006
1007- Canvas: fixed bugs in lower() and tkraise() methods.
1008
1009- SocketServer: API change (added overridable close_request() method)
1010 so that the TCP server can explicitly close the request.
1011
1012- pstats: Eric Raymond added a simple interactive statistics browser,
1013 invoked when the module is run as a script.
1014
1015- locale: fixed a problem in format().
1016
1017- webbrowser: made it work when the BROWSER environment variable has a
1018 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1019 KDE 2. Fixed some other nits.
1020
1021- unittest: changes to allow using a different exception than
1022 AssertionError, and added a few more function aliases. Some other
1023 small changes.
1024
1025- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1026
1027- asynchat: fixed a critical bug in asynchat that slipped through the
1028 2.1b2 release. Fixed another rare bug.
1029
1030- Fix some unqualified except: clauses (always a bad code example).
1031
1032XML
1033
1034- pyexpat: new API get_version_string().
1035
1036- Fixed some minidom bugs.
1037
1038Extensions
1039
1040- Fixed a core dump in _weakref. Removed the weakref.mapping()
1041 function (it adds nothing to the API).
1042
1043- Rationalized the use of header files in the readline module, to make
1044 it compile (albeit with some warnings) with the very recent readline
1045 4.2, without breaking for earlier versions.
1046
1047- Hopefully fixed a buffering problem in linuxaudiodev.
1048
1049- Attempted a fix to make the OpenSSL support in the socket module
1050 work again with pre-0.9.5 versions of OpenSSL.
1051
1052Tests
1053
1054- Added a test case for asynchat and asyncore.
1055
1056- Removed coupling between tests where one test failing could break
1057 another.
1058
1059Tools
1060
1061- Ping added an interactive help browser to pydoc, fixed some nits
1062 in the rest of the pydoc code, and added some features to his
1063 inspect module.
1064
1065- An updated python-mode.el version 4.1 which integrates Ken
1066 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1067 much nicer in XEmacs and Emacs. When stepping through your program
1068 with pdb, in either the shell window or the *Python* window, the
1069 source file and line will be tracked by an arrow. Very cool!
1070
1071- IDLE: syntax warnings in interactive mode are changed into errors.
1072
1073- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001074 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001075
1076- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001077
Barry Warsaw11e89c72001-04-11 20:37:57 +00001078
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001079What's New in Python 2.1 beta 2?
1080================================
1081
Guido van Rossum053ae352001-03-22 14:17:21 +00001082(Unlisted are many fixed bugs, more documentation, etc.)
1083
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001084Core language, builtins, and interpreter
1085
Guido van Rossum053ae352001-03-22 14:17:21 +00001086- The nested scopes work (enabled by "from __future__ import
1087 nested_scopes") is completed; in particular, the future now extends
1088 into code executed through exec, eval() and execfile(), and into the
1089 interactive interpreter.
1090
1091- When calling a base class method (e.g. BaseClass.__init__(self)),
1092 this is now allowed even if self is not strictly spoken a class
1093 instance (e.g. when using metaclasses or the Don Beaudry hook).
1094
1095- Slice objects are now comparable but not hashable; this prevents
1096 dict[:] from being accepted but meaningless.
1097
1098- Complex division is now calculated using less braindead algorithms.
1099 This doesn't change semantics except it's more likely to give useful
1100 results in extreme cases. Complex repr() now uses full precision
1101 like float repr().
1102
1103- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1104
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001105- It is illegal to assign to the name __debug__, which is set when the
1106 interpreter starts. It is effectively a compile-time constant.
1107
1108- A warning will be issued if a global statement for a variable
1109 follows a use or assignment of that variable.
1110
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001111Standard library
1112
Guido van Rossum053ae352001-03-22 14:17:21 +00001113- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1114 inspired by JUnit), is now part of the standard library. You now
1115 have a choice of two testing frameworks: unittest requires you to
1116 write testcases as separate code, doctest gathers them from
1117 docstrings. Both approaches have their advantages and
1118 disadvantages.
1119
1120- A new module Tix was added, which wraps the Tix extension library
1121 for Tk. With that module, it is not necessary to statically link
1122 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1123 require" command. See Demo/tix/.
1124
1125- tzparse.py is now obsolete.
1126
1127- In gzip.py, the seek() and tell() methods are removed -- they were
1128 non-functional anyway, and it's better if callers can test for their
1129 existence with hasattr().
1130
1131Python/C API
1132
1133- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1134 that's already in the dictionary during a PyDict_Next() iteration.
1135 This used to fail occasionally when a dictionary resize operation
1136 could be triggered that would rehash all the keys. All other
1137 modifications to the dictionary are still off-limits during a
1138 PyDict_Next() iteration!
1139
1140- New extended APIs related to passing compiler variables around.
1141
1142- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1143 implement isinstance() and issubclass().
1144
1145- Py_BuildValue() now has a "D" conversion to create a Python complex
1146 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001147
Fred Drake4e262a92001-03-22 18:26:47 +00001148- Extensions types which support weak references must now set the
1149 field allocated for the weak reference machinery to NULL themselves;
1150 this is done to avoid the cost of checking each object for having a
1151 weakly referencable type in PyObject_INIT(), since most types are
1152 not weakly referencable.
1153
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001154- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1155 free variables and cell variables to and from the frame's f_locals.
1156
1157- Variants of several functions defined in pythonrun.h have been added
1158 to support the nested_scopes future statement. The variants all end
1159 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1160 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1161 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001162 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001163
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001164Distutils
1165
1166- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1167 into the release tree.
1168
Tim Peters0e57abf2001-05-02 07:39:38 +00001169- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001170 (an uninstaller, more customization of the installer's display)
1171
1172- from Jack Jansen: added Mac-specific code to generate a dialog for
1173 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001174 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001175 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001176
1177- added 'platforms' and 'keywords' to the set of metadata that can be
1178 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001179
1180- applied patches from Jason Tishler to make the compiler class work with
1181 Cygwin.
1182
1183
Tim Peters2fe289a2001-03-01 22:19:38 +00001184What's New in Python 2.1 beta 1?
1185================================
Tim Petersd66595f2001-02-04 03:09:53 +00001186
1187Core language, builtins, and interpreter
1188
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001189- Following an outcry from the community about the amount of code
1190 broken by the nested scopes feature introduced in 2.1a2, we decided
1191 to make this feature optional, and to wait until Python 2.2 (or at
1192 least 6 months) to make it standard. The option can be enabled on a
1193 per-module basis by adding "from __future__ import nested_scopes" at
1194 the beginning of a module (before any other statements, but after
1195 comments and an optional docstring). See PEP 236 (Back to the
1196 __future__) for a description of the __future__ statement. PEP 227
1197 (Statically Nested Scopes) has been updated to reflect this change,
1198 and to clarify the semantics in a number of endcases.
1199
1200- The nested scopes code, when enabled, has been hardened, and most
1201 bugs and memory leaks in it have been fixed.
1202
1203- Compile-time warnings are now generated for a number of conditions
1204 that will break or change in meaning when nested scopes are enabled:
1205
1206 - Using "from...import *" or "exec" without in-clause in a function
1207 scope that also defines a lambda or nested function with one or
1208 more free (non-local) variables. The presence of the import* or
1209 bare exec makes it impossible for the compiler to determine the
1210 exact set of local variables in the outer scope, which makes it
1211 impossible to determine the bindings for free variables in the
1212 inner scope. To avoid the warning about import *, change it into
1213 an import of explicitly name object, or move the import* statement
1214 to the global scope; to avoid the warning about bare exec, use
1215 exec...in... (a good idea anyway -- there's a possibility that
1216 bare exec will be deprecated in the future).
1217
1218 - Use of a global variable in a nested scope with the same name as a
1219 local variable in a surrounding scope. This will change in
1220 meaning with nested scopes: the name in the inner scope will
1221 reference the variable in the outer scope rather than the global
1222 of the same name. To avoid the warning, either rename the outer
1223 variable, or use a global statement in the inner function.
1224
Neil Schemenauera35c6882001-02-27 04:45:05 +00001225- An optional object allocator has been included. This allocator is
1226 optimized for Python objects and should be faster and use less memory
1227 than the standard system allocator. It is not enabled by default
1228 because of possible thread safety problems. The allocator is only
1229 protected by the Python interpreter lock and it is possible that some
1230 extension modules require a thread safe allocator. The object
1231 allocator can be enabled by providing the "--with-pymalloc" option to
1232 configure.
1233
Tim Petersd66595f2001-02-04 03:09:53 +00001234Standard library
1235
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001236- pyexpat now detects the expat version if expat.h defines it. A
1237 number of additional handlers are provided, which are only available
1238 since expat 1.95. In addition, the methods SetParamEntityParsing and
1239 GetInputContext of Parser objects are available with 1.95.x
1240 only. Parser objects now provide the ordered_attributes and
1241 specified_attributes attributes. A new module expat.model was added,
1242 which offers a number of additional constants if 1.95.x is used.
1243
1244- xml.dom offers the new functions registerDOMImplementation and
1245 getDOMImplementation.
1246
1247- xml.dom.minidom offers a toprettyxml method. A number of DOM
1248 conformance issues have been resolved. In particular, Element now
1249 has an hasAttributes method, and the handling of namespaces was
1250 improved.
1251
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001252- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1253 getting information about live Python code, and pydoc.py, a module
1254 for interactively converting docstrings to HTML or text.
1255 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001256 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001257 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1258 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001259
Tim Peters1eff7962001-03-01 02:31:33 +00001260- New library module difflib.py, primarily packaging the SequenceMatcher
1261 class at the heart of the popular ndiff.py file-comparison tool.
1262
1263- doctest.py (a framework for verifying Python code examples in docstrings)
1264 is now part of the std library.
1265
Tim Petersd66595f2001-02-04 03:09:53 +00001266Windows changes
1267
Guido van Rossume3955a82001-03-02 14:05:59 +00001268- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1269 small GUI that lets you browse the module docstrings using your
1270 default web browser.
1271
Tim Peters1eff7962001-03-01 02:31:33 +00001272- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1273 Platforms) is implemented. See
1274
1275 http://python.sourceforge.net/peps/pep-0235.html
1276
1277 for full details, especially the "Current Lower-Left Semantics" section.
1278 The new Windows import rules are simpler than before:
1279
1280 A. If the PYTHONCASEOK environment variable exists, same as
1281 before: silently accept the first case-insensitive match of any
1282 kind; raise ImportError if none found.
1283
1284 B. Else search sys.path for the first case-sensitive match; raise
1285 ImportError if none found.
1286
1287 The same rules have been implented on other platforms with case-
1288 insensitive but case-preserving filesystems too (including Cygwin, and
1289 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001290
Tim Peters25a9ce32001-02-19 07:06:36 +00001291- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1292 what it's supposed to do (and does do under NT and 2000) via direct
1293 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001294 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001295 all Win9x systems before.
1296
Tim Peters1eff7962001-03-01 02:31:33 +00001297- Build: Subproject _test (effectively) renamed to _testcapi.
1298
Tim Peters2fe289a2001-03-01 22:19:38 +00001299New platforms
1300
1301- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1302 Thanks to Steven Majewski!
1303
1304- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1305 Tishler!
1306
Guido van Rossum9089b272001-03-02 06:49:50 +00001307- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1308 Schwertberger! See RISCOS/README for more information -- it seems
1309 that because of the bizarre filename conventions on RISCOS, no port
1310 to that platform is easy. Note that the new variable os.endsep is
1311 silently supported in order to make life easier on this platform,
1312 but we don't advertise it because it's not worth for most folks to
1313 care about RISCOS portability.
1314
Tim Peters25a9ce32001-02-19 07:06:36 +00001315
Tim Petersd7b5e882001-01-25 03:36:26 +00001316What's New in Python 2.1 alpha 2?
1317=================================
Tim Peters40ead762001-01-27 05:35:26 +00001318
Tim Petersd7b5e882001-01-25 03:36:26 +00001319Core language, builtins, and interpreter
1320
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001321- Scopes nest. If a name is used in a function or class, but is not
1322 local, the definition in the nearest enclosing function scope will
1323 be used. One consequence of this change is that lambda statements
1324 could reference variables in the namespaces where the lambda is
1325 defined. In some unusual cases, this change will break code.
1326
1327 In all previous version of Python, names were resolved in exactly
1328 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001329 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001330 function A is defined within a function B, the names bound in B are
1331 not visible in A. The new rules make names bound in B visible in A,
1332 unless A contains a name binding that hides the binding in B.
1333
1334 Section 4.1 of the reference manual describes the new scoping rules
1335 in detail. The test script in Lib/test/test_scope.py demonstrates
1336 some of the effects of the change.
1337
1338 The new rules will cause existing code to break if it defines nested
1339 functions where an outer function has local variables with the same
1340 name as globals or builtins used by the inner function. Example:
1341
1342 def munge(str):
1343 def helper(x):
1344 return str(x)
1345 if type(str) != type(''):
1346 str = helper(str)
1347 return str.strip()
1348
1349 Under the old rules, the name str in helper() is bound to the
1350 builtin function str(). Under the new rules, it will be bound to
1351 the argument named str and an error will occur when helper() is
1352 called.
1353
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001354- The compiler will report a SyntaxError if "from ... import *" occurs
1355 in a function or class scope. The language reference has documented
1356 that this case is illegal, but the compiler never checked for it.
1357 The recent introduction of nested scope makes the meaning of this
1358 form of name binding ambiguous. In a future release, the compiler
1359 may allow this form when there is no possibility of ambiguity.
1360
Tim Peters40ead762001-01-27 05:35:26 +00001361- repr(string) is easier to read, now using hex escapes instead of octal,
1362 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1363
1364 >>> "\texample \r\n" + chr(0) + chr(255)
1365 '\texample \r\n\x00\xff' # in 2.1
1366 '\011example \015\012\000\377' # in 2.0
1367
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001368- Functions are now compared and hashed by identity, not by value, since
1369 the func_code attribute is writable.
1370
Fred Drakefb9d7122001-02-01 20:00:40 +00001371- Weak references (PEP 205) have been added. This involves a few
1372 changes in the core, an extension module (_weakref), and a Python
1373 module (weakref). The weakref module is the public interface. It
1374 includes support for "explicit" weak references, proxy objects, and
1375 mappings with weakly held values.
1376
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001377- A 'continue' statement can now appear in a try block within the body
1378 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001379 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001380
Tim Petersd7b5e882001-01-25 03:36:26 +00001381Standard library
1382
Barry Warsaw30dbd142001-01-31 22:14:01 +00001383- mailbox.py now has a new class, PortableUnixMailbox which is
1384 identical to UnixMailbox but uses a more portable scheme for
1385 determining From_ separators. Also, the constructors for all the
1386 classes in this module have a new optional `factory' argument, which
1387 is a callable used when new message classes must be instantiated by
1388 the next() method.
1389
Tim Petersd7b5e882001-01-25 03:36:26 +00001390- random.py is now self-contained, and offers all the functionality of
1391 the now-deprecated whrandom.py. See the docs for details. random.py
1392 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001393 and restoring the internal state of the generator; and jumpahead(n),
1394 for quickly forcing the internal state to be the same as if n calls to
1395 random() had been made. The latter is particularly useful for multi-
1396 threaded programs, creating one instance of the random.Random() class for
1397 each thread, then using .jumpahead() to force each instance to use a
1398 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001399
Tim Peters0de88fc2001-02-01 04:59:18 +00001400- random.py's seed() function is new. For bit-for-bit compatibility with
1401 prior releases, use the whseed function instead. The new seed function
1402 addresses two problems: (1) The old function couldn't produce more than
1403 about 2**24 distinct internal states; the new one about 2**45 (the best
1404 that can be done in the Wichmann-Hill generator). (2) The old function
1405 sometimes produced identical internal states when passed distinct
1406 integers, and there was no simple way to predict when that would happen;
1407 the new one guarantees to produce distinct internal states for all
1408 arguments in [0, 27814431486576L).
1409
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001410- The socket module now supports raw packets on Linux. The socket
1411 family is AF_PACKET.
1412
Tim Peters9ea17ac2001-02-02 05:57:15 +00001413- test_capi.py is a start at running tests of the Python C API. The tests
1414 are implemented by the new Modules/_testmodule.c.
1415
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001416- A new extension module, _symtable, provides provisional access to the
1417 internal symbol table used by the Python compiler. A higher-level
1418 interface will be added on top of _symtable in a future release.
1419
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001420- Removed the obsolete soundex module.
1421
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001422- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1423 the isSameNode method; NamedNodeMap the get method.
1424
1425- xml.sax.expatreader supports the lexical handler property; it
1426 generates comment, startCDATA, and endCDATA events.
1427
Tim Petersee826f82001-01-31 19:39:44 +00001428Windows changes
1429
1430- Build procedure: the zlib project is built in a different way that
1431 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001432 the zlib binary used. See PCbuild\readme.txt for details. Your old
1433 zlib-related directories can be deleted; you'll need to download fresh
1434 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001435
Tim Peters9ea17ac2001-02-02 05:57:15 +00001436- Build: New subproject _test for the benefit of test_capi.py (see above).
1437
Tim Petersb16c56f2001-02-02 21:24:51 +00001438- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1439 interface to some Python compiler internals).
1440
1441- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001442 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001443
Tim Petersa3a3a032000-11-30 05:22:44 +00001444What's New in Python 2.1 alpha 1?
1445=================================
1446
1447Core language, builtins, and interpreter
1448
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001449- There is a new Unicode companion to the PyObject_Str() API
1450 called PyObject_Unicode(). It behaves in the same way as the
1451 former, but assures that the returned value is an Unicode object
1452 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001453
Guido van Rossumf98eda02001-01-17 15:54:45 +00001454- The comparison operators support "rich comparison overloading" (PEP
1455 207). C extension types can provide a rich comparison function in
1456 the new tp_richcompare slot in the type object. The cmp() function
1457 and the C function PyObject_Compare() first try the new rich
1458 comparison operators before trying the old 3-way comparison. There
1459 is also a new C API PyObject_RichCompare() (which also falls back on
1460 the old 3-way comparison, but does not constrain the outcome of the
1461 rich comparison to a Boolean result).
1462
1463 The rich comparison function takes two objects (at least one of
1464 which is guaranteed to have the type that provided the function) and
1465 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1466 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1467 object, which may be NotImplemented (in which case the tp_compare
1468 slot function is used as a fallback, if defined).
1469
1470 Classes can overload individual comparison operators by defining one
1471 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001472 __ge__. There are no explicit "reflected argument" versions of
1473 these; instead, __lt__ and __gt__ are each other's reflection,
1474 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1475 reflection (similar at the C level). No other implications are
1476 made; in particular, Python does not assume that == is the Boolean
1477 inverse of !=, or that < is the Boolean inverse of >=. This makes
1478 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001479
1480 Classes or types that want to implement (in)equality tests but not
1481 the ordering operators (i.e. unordered types) should implement ==
1482 and !=, and raise an error for the ordering operators.
1483
Guido van Rossuma88479f2001-01-18 14:28:08 +00001484 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001485 Boolean; e.g. a matrix type might want to return a matrix of bits
1486 for A < B, giving elementwise comparisons. Such types should ensure
1487 that any interpretation of their value in a Boolean context raises
1488 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1489 at the C level) to always raise an exception.
1490
Guido van Rossuma88479f2001-01-18 14:28:08 +00001491- Complex numbers use rich comparisons to define == and != but raise
1492 an exception for <, <=, > and >=. Unfortunately, this also means
1493 that cmp() of two complex numbers raises an exception when the two
1494 numbers differ. Since it is not mathematically meaningful to compare
1495 complex numbers except for equality, I hope that this doesn't break
1496 too much code.
1497
Tim Peters3389f192001-02-18 08:48:49 +00001498- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001499 not defined by the language, other than that it's arbitrary but
1500 consistent (see the Reference Manual). An implementation detail changed
1501 in 2.1a1 such that None now compares less than any other object. Code
1502 relying on this new behavior (like code that relied on the previous
1503 behavior) does so at its own risk.
1504
Barry Warsaw573b5412001-01-15 20:43:18 +00001505- Functions and methods now support getting and setting arbitrarily
1506 named attributes (PEP 232). Functions have a new __dict__
1507 (a.k.a. func_dict) which hold the function attributes. Methods get
1508 and set attributes on their underlying im_func. It is a TypeError
1509 to set an attribute on a bound method.
1510
Guido van Rossum051e3352001-01-15 19:11:10 +00001511- The xrange() object implementation has been improved so that
1512 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1513 limitation that in this case len(xrange(sys.maxint)) can't be
1514 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1515 work fine as long as the index i doesn't actually reach 2**31.
1516 (Python uses regular ints for sequence and string indices; fixing
1517 that is much more work.)
1518
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001519- Two changes to from...import:
1520
Guido van Rossumba381232001-02-03 15:06:40 +00001521 1) "from M import X" now works even if (after loading module M)
1522 sys.modules['M'] is not a real module; it's basically a getattr()
1523 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001524
1525 2) "from M import *" now looks for M.__all__ to decide which names to
1526 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1527 filters out names starting with '_' as before. Whether or not
1528 __all__ exists, there's no restriction on the type of M.
1529
Guido van Rossumf61f1662001-01-10 20:13:55 +00001530- File objects have a new method, xreadlines(). This is the fastest
1531 way to iterate over all lines in a file:
1532
1533 for line in file.xreadlines():
1534 ...do something to line...
1535
1536 See the xreadlines module (mentioned below) for how to do this for
1537 other file-like objects.
1538
1539- Even if you don't use file.xreadlines(), you may expect a speedup on
1540 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001541 quite a bit in platform-specific ways: on systems (like Linux) that
1542 support flockfile(), getc_unlocked(), and funlockfile(), those are
1543 used by default. On systems (like Windows) without getc_unlocked(),
1544 a complicated (but still thread-safe) method using fgets() is used by
1545 default.
1546
Tim Petersd52269b2001-01-25 06:23:18 +00001547 You can force use of the fgets() method by #define'ing
1548 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001549 getc_unlocked()).
1550
Tim Petersd52269b2001-01-25 06:23:18 +00001551 You can force fgets() not to be used by #define'ing
1552 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001553 test_bufio.py fails -- and let us know if it does!).
1554
1555- In addition, the fileinput module, while still slower than the other
1556 methods on most platforms, has been sped up too, by using
1557 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001558
1559- Support for run-time warnings has been added, including a new
1560 command line option (-W) to specify the disposition of warnings.
1561 See the description of the warnings module below.
1562
1563- Extensive changes have been made to the coercion code. This mostly
1564 affects extension modules (which can now implement mixed-type
1565 numerical operators without having to use coercion), but
1566 occasionally, in boundary cases the coercion semantics have changed
1567 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001568 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001569 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001570 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001571
Guido van Rossumf98eda02001-01-17 15:54:45 +00001572- In connection with the coercion changes, a new built-in singleton
1573 object, NotImplemented is defined. This can be returned for
1574 operations that wish to indicate they are not implemented for a
1575 particular combination of arguments. From C, this is
1576 Py_NotImplemented.
1577
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001578- The interpreter accepts now bytecode files on the command line even
1579 if they do not have a .pyc or .pyo extension. On Linux, after executing
1580
Martin v. Löwise214baa2001-02-04 22:37:56 +00001581import imp,sys,string
1582magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1583reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1584open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001585
1586 any byte code file can be used as an executable (i.e. as an argument
1587 to execve(2)).
1588
Tim Peters9940b802000-12-01 07:59:35 +00001589- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001590 character. In 1.6 and earlier, they never produced a sign,
1591 and raised an error if the value of the long was too large
1592 to fit in a Python int. In 2.0, they produced a sign if and
1593 only if too large to fit in an int. This was inconsistent
1594 across platforms (because the size of an int varies across
1595 platforms), and inconsistent with hex() and oct(). Example:
1596
1597 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001598 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001599 'ffffffbe' # in 2.0 and before, on 32-bit machines
1600 >>> hex(-0x42L)
1601 '-0x42L' # in all versions of Python
1602
Tim Peters9940b802000-12-01 07:59:35 +00001603 The behavior of %d formats for negative Python longs remains
1604 the same as in 2.0 (although in 1.6 and before, they raised
1605 an error if the long didn't fit in a Python int).
1606
1607 %u formats don't make sense for Python longs, but are allowed
1608 and treated the same as %d in 2.1. In 2.0, a negative long
1609 formatted via %u produced a sign if and only if too large to
1610 fit in an int. In 1.6 and earlier, a negative long formatted
1611 via %u raised an error if it was too big to fit in an int.
1612
Guido van Rossum3661d392000-12-12 22:10:31 +00001613- Dictionary objects have an odd new method, popitem(). This removes
1614 an arbitrary item from the dictionary and returns it (in the form of
1615 a (key, value) pair). This can be useful for algorithms that use a
1616 dictionary as a bag of "to do" items and repeatedly need to pick one
1617 item. Such algorithms normally end up running in quadratic time;
1618 using popitem() they can usually be made to run in linear time.
1619
Tim Peters36cdad12000-12-29 02:06:45 +00001620Standard library
1621
Thomas Woutersfe385252001-01-19 23:16:56 +00001622- In the time module, the time argument to the functions strftime,
1623 localtime, gmtime, asctime and ctime is now optional, defaulting to
1624 the current time (in the local timezone).
1625
Guido van Rossumda91f222001-01-15 16:36:08 +00001626- The ftplib module now defaults to passive mode, which is deemed a
1627 more useful default given that clients are often inside firewalls
1628 these days. Note that this could break if ftplib is used to connect
1629 to a *server* that is inside a firewall, from outside; this is
1630 expected to be a very rare situation. To fix that, you can call
1631 ftp.set_pasv(0).
1632
Martin v. Löwis10a27872001-01-13 09:54:41 +00001633- The module site now treats .pth files not only for path configuration,
1634 but also supports extensions to the initialization code: Lines starting
1635 with import are executed.
1636
Guido van Rossumf61f1662001-01-10 20:13:55 +00001637- There's a new module, warnings, which implements a mechanism for
1638 issuing and filtering warnings. There are some new built-in
1639 exceptions that serve as warning categories, and a new command line
1640 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1641 turns warnings into errors). warnings.warn(message[, category])
1642 issues a warning message; this can also be called from C as
1643 PyErr_Warn(category, message).
1644
1645- A new module xreadlines was added. This exports a single factory
1646 function, xreadlines(). The intention is that this code is the
1647 absolutely fastest way to iterate over all lines in an open
1648 file(-like) object:
1649
1650 import xreadlines
1651 for line in xreadlines.xreadlines(file):
1652 ...do something to line...
1653
1654 This is equivalent to the previous the speed record holder using
1655 file.readlines(sizehint). Note that if file is a real file object
1656 (as opposed to a file-like object), this is equivalent:
1657
1658 for line in file.xreadlines():
1659 ...do something to line...
1660
Tim Peters36cdad12000-12-29 02:06:45 +00001661- The bisect module has new functions bisect_left, insort_left,
1662 bisect_right and insort_right. The old names bisect and insort
1663 are now aliases for bisect_right and insort_right. XXX_right
1664 and XXX_left methods differ in what happens when the new element
1665 compares equal to one or more elements already in the list: the
1666 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001667 right. Code that doesn't care where equal elements end up should
1668 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001669
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001670- The new curses.panel module wraps the panel library that forms part
1671 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1672
Guido van Rossumf61f1662001-01-10 20:13:55 +00001673- The SocketServer module now sets the allow_reuse_address flag by
1674 default in the TCPServer class.
1675
1676- A new function, sys._getframe(), returns the stack frame pointer of
1677 the caller. This is intended only as a building block for
1678 higher-level mechanisms such as string interpolation.
1679
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001680- The pyexpat module supports a number of new handlers, which are
1681 available only in expat 1.2. If invocation of a callback fails, it
1682 will report an additional frame in the traceback. Parser objects
1683 participate now in garbage collection. If expat reports an unknown
1684 encoding, pyexpat will try to use a Python codec; that works only
1685 for single-byte charsets. The parser type objects is exposed as
1686 XMLParserObject.
1687
1688- xml.dom now offers standard definitions for symbolic node type and
1689 exception code constants, and a hierarchy of DOM exceptions. minidom
1690 was adjusted to use them.
1691
1692- The conformance of xml.dom.minidom to the DOM specification was
1693 improved. It detects a number of additional error cases; the
1694 previous/next relationship works even when the tree is modified;
1695 Node supports the normalize() method; NamedNodeMap, DocumentType and
1696 DOMImplementation classes were added; Element supports the
1697 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1698 method.
1699
Guido van Rossumf61f1662001-01-10 20:13:55 +00001700Build issues
1701
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001702- For Unix (and Unix-compatible) builds, configuration and building of
1703 extension modules is now greatly automated. Rather than having to
1704 edit the Modules/Setup file to indicate which modules should be
1705 built and where their include files and libraries are, a
1706 distutils-based setup.py script now takes care of building most
1707 extension modules. All extension modules built this way are built
1708 as shared libraries. Only a few modules that must be linked
1709 statically are still listed in the Setup file; you won't need to
1710 edit their configuration.
1711
1712- Python should now build out of the box on Cygwin. If it doesn't,
1713 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001714
1715- Python now always uses its own (renamed) implementation of getopt()
1716 -- there's too much variation among C library getopt()
1717 implementations.
1718
1719- C++ compilers are better supported; the CXX macro is always set to a
1720 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001721
Tim Petersd92dfe02000-12-12 01:18:41 +00001722Windows changes
1723
1724- select module: By default under Windows, a select() call
1725 can specify no more than 64 sockets. Python now boosts
1726 this Microsoft default to 512. If you need even more than
1727 that, see the MS docs (you'll need to #define FD_SETSIZE
1728 and recompile Python from source).
1729
Guido van Rossumf61f1662001-01-10 20:13:55 +00001730- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1731 subdirectory is no more!
1732
Tim Petersa3a3a032000-11-30 05:22:44 +00001733
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001734What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001735=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001736
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001737Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001738changes are in the file HISTORY. If you are making the jump directly
1739from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1740HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001741
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001742Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1743the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1744http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001745
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001746--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001747
1748======================================================================
1749
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001750What's new in 2.0 (since release candidate 1)?
1751==============================================
1752
1753Standard library
1754
1755- The copy_reg module was modified to clarify its intended use: to
1756 register pickle support for extension types, not for classes.
1757 pickle() will raise a TypeError if it is passed a class.
1758
1759- Fixed a bug in gettext's "normalize and expand" code that prevented
1760 it from finding an existing .mo file.
1761
1762- Restored support for HTTP/0.9 servers in httplib.
1763
Tim Peters989b7b92000-10-16 20:24:53 +00001764- The math module was changed to stop raising OverflowError in case of
1765 underflow, and return 0 instead in underflow cases. Whether Python
1766 used to raise OverflowError in case of underflow was platform-
1767 dependent (it did when the platform math library set errno to ERANGE
1768 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001769
1770- Fixed a bug in StringIO that occurred when the file position was not
1771 at the end of the file and write() was called with enough data to
1772 extend past the end of the file.
1773
1774- Fixed a bug that caused Tkinter error messages to get lost on
1775 Windows. The bug was fixed by replacing direct use of
1776 interp->result with Tcl_GetStringResult(interp).
1777
1778- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1779 redirect response.
1780
1781- Several changes were made to distutils: Some debugging code was
1782 removed from util. Fixed the installer used when an external zip
1783 program (like WinZip) is not found; the source code for this
1784 installer is in Misc/distutils. check_lib() was modified to behave
1785 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1786 test for whether installed modules are on sys.path was changed to
1787 use both normcase() and normpath().
1788
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001789- Several minor bugs were fixed in the xml package (the minidom,
1790 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001791
1792- The regression test driver (regrtest.py) behavior when invoked with
1793 -l changed: It now reports a count of objects that are recognized as
1794 garbage but not freed by the garbage collector.
1795
Tim Peters989b7b92000-10-16 20:24:53 +00001796- The regression test for the math module was changed to test
1797 exceptional behavior when the test is run in verbose mode. Python
1798 cannot yet guarantee consistent exception behavior across platforms,
1799 so the exception part of test_math is run only in verbose mode, and
1800 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001801
1802Internals
1803
1804- PyOS_CheckStack() has been disabled on Win64, where it caused
1805 test_sre to fail.
1806
1807Build issues
1808
1809- Changed compiler flags, so that gcc is always invoked with -Wall and
1810 -Wstrict-prototypes. Users compiling Python with GCC should see
1811 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001812 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001813 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001814
Tim Petersa3a3a032000-11-30 05:22:44 +00001815- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001816
1817Tools and other miscellany
1818
1819- The compiler in Tools/compiler was updated to support the new
1820 language features introduced in 2.0: extended print statement, list
1821 comprehensions, and augmented assignments. The new compiler should
1822 also be backwards compatible with Python 1.5.2; the compiler will
1823 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001824 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001825
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001826What's new in 2.0 release candidate 1 (since beta 2)?
1827=====================================================
1828
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001829What is release candidate 1?
1830
1831We believe that release candidate 1 will fix all known bugs that we
1832intend to fix for the 2.0 final release. This release should be a bit
1833more stable than the previous betas. We would like to see even more
1834widespread testing before the final release, so we are producing this
1835release candidate. The final release will be exactly the same unless
1836any show-stopping (or brown bag) bugs are found by testers of the
1837release candidate.
1838
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001839All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001840to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001841
1842Core language, builtins, and interpreter
1843
1844- A bug that caused crashes when __coerce__ was used with augmented
1845 assignment, e.g. +=, was fixed.
1846
1847- Raise ZeroDivisionError when raising zero to a negative number,
1848 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1849 power operator and the result of math.pow(0.0, -2.0) will vary by
1850 platform. On Linux, it raises a ValueError.
1851
1852- A bug in Unicode string interpolation was fixed that occasionally
1853 caused errors with formats including "%%". For example, the
1854 following expression "%% %s" % u"abc" no longer raises a TypeError.
1855
1856- Compilation of deeply nested expressions raises MemoryError instead
1857 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1858
1859- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1860 rendering them useless. They are now written in binary mode again.
1861
1862Standard library
1863
1864- Keyword arguments are now accepted for most pattern and match object
1865 methods in SRE, the standard regular expression engine.
1866
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001867- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001868 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001869
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001870- Several bugs in the Unicode handling and error handling in _tkinter
1871 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001872
1873- Fix memory management errors in Merge() and Tkapp_Call() routines.
1874
1875- Several changes were made to cStringIO to make it compatible with
1876 the file-like object interface and with StringIO. If operations are
1877 performed on a closed object, an exception is raised. The truncate
1878 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001879 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001880
1881- There were many changes made to the linuxaudiodev module and its
1882 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001883 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001884
1885 Note that this module is named poorly, because it should work
1886 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001887 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001888
1889 The module now raises exceptions when errors occur instead of
1890 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1891 audio) and defines a getptr() method that calls the
1892 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1893
1894- The library_version attribute, introduced in an earlier beta, was
1895 removed because it can not be supported with early versions of the C
1896 readline library, which provides no way to determine the version at
1897 compile-time.
1898
1899- The binascii module is now enabled on Win64.
1900
Tim Peters46446d62000-10-09 21:19:31 +00001901- tokenize.py no longer suffers "recursion depth" errors when parsing
1902 programs with very long string literals.
1903
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001904Internals
1905
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001906- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001907 which is called when the interpreter starts up to determine where
1908 the standard library is installed. These vulnerabilities affect all
1909 previous versions of Python and can be exploited by setting very
1910 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1911 setuid Python script, although use of the wrapper in
1912 Misc/setuid-prog.c will eliminate the vulnerability.
1913
1914- Fixed garbage collection bugs in instance creation that were
1915 triggered when errors occurred during initialization. The solution,
1916 applied in cPickle and in PyInstance_New(), is to call
1917 PyObject_GC_Init() after the initialization of the object's
1918 container attributes is complete.
1919
1920- pyexpat adds definitions of PyModule_AddStringConstant and
1921 PyModule_AddObject if the Python version is less than 2.0, which
1922 provides compatibility with PyXML on Python 1.5.2.
1923
1924- If the platform has a bogus definition for LONG_BIT (the number of
1925 bits in a long), an error will be reported at compile time.
1926
1927- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1928 collection crashes and possibly other, unreported crashes.
1929
1930- Fixed a memory leak in _PyUnicode_Fini().
1931
1932Build issues
1933
1934- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001935 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001936 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001937
1938- The mmap.PAGESIZE constant is now initialized using sysconf when
1939 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1940
1941- The md5 file should now compile on all platforms.
1942
1943- The select module now compiles on platforms that do not define
1944 POLLRDNORM and related constants.
1945
1946- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001947 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001948
Jeremy Hylton10921202000-10-09 18:34:12 +00001949- BeOS: A number of changes were made to the build and installation
1950 process. ar-fake now operates on a directory of object files.
1951 dl_export.h is gone, and its macros now appear on the mwcc command
1952 line during build on PPC BeOS.
1953
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001954- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001955 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001956
1957- Cygwin: Support for shared libraries, Tkinter, and sockets.
1958
1959- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1960
1961Tools and other miscellany
1962
1963- Removed debugging prints from main used with freeze.
1964
Tim Peters46446d62000-10-09 21:19:31 +00001965- IDLE auto-indent no longer crashes when it encounters Unicode
1966 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001967
1968What's new in 2.0 beta 2 (since beta 1)?
1969========================================
1970
1971Core language, builtins, and interpreter
1972
Tim Peters482c0212000-09-26 06:33:09 +00001973- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001974 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001975
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001976- Add -h and -V command line options to print the usage message and
1977 Python version number and exit immediately.
1978
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001979- eval() and exec accept Unicode objects as code parameters.
1980
1981- getattr() and setattr() now also accept Unicode objects for the
1982 attribute name, which are converted to strings using the default
1983 encoding before lookup.
1984
1985- Multiplication on string and Unicode now does proper bounds
1986 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1987 string is too long."
1988
1989- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001990 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001991
Jeremy Hylton1b618592000-09-26 05:32:36 +00001992
1993Standard library and extensions
1994
Guido van Rossum5b08f132001-04-16 02:05:23 +00001995- socket module: the OpenSSL code now adds support for RAND_status()
1996 and EGD (Entropy Gathering Device).
1997
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001998- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001999 argument checking; it still takes no arguments.
2000
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002001- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002002
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002003- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002004
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002005- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002006
2007- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002008 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002009
2010- copy: Copy Unicode objects atomically.
2011
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002012- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002013
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002014- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002015
Fred Drake67233bc2000-09-26 16:40:27 +00002016- dbm: Add get() and setdefault() methods to dbm object. Add constant
2017 `library' to module that names the library used. Added doc strings
2018 and method names to error messages. Uses configure to determine
2019 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2020 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002021
2022- distutils: Update to version 0.9.3.
2023
2024- dl: Add several dl.RTLD_ constants.
2025
2026- fpectl: Now supported on FreeBSD.
2027
2028- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2029 found by the collector will be saved in gc.garbage. This is useful
2030 for debugging a program that creates reference cycles.
2031
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002032- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002033 of HTTP class. Do not close socket on zero-length response. Do not
2034 crash when server sends invalid content-length header.
2035
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002036- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002037
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002038- marshal: When reading a short, sign-extend on platforms where shorts
2039 are bigger than 16 bits. When reading a long, repair the unportable
2040 sign extension that was being done for 64-bit machines. (It assumed
2041 that signed right shift sign-extends.)
2042
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002043- operator: Add contains(), invert(), __invert__() as aliases for
2044 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002045
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002046- os: Add support for popen2() and popen3() on all platforms where
2047 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002048
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002049- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002050 clicking on a file in Explorer (or passing the file name to the
2051 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002052
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002053- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002054 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002055
2056- pickle: Now raises ValueError when an invalid pickle that contains
2057 a non-string repr where a string repr was expected. This behavior
2058 matches cPickle.
2059
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002060- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002061
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002062- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002063
2064- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002065 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002066 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002067
2068- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002069 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002070
2071- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002072 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002073 few cycles during startup since the first call to
2074 setdefaultencoding() will initialize the codec registry and the
2075 encodings package.
2076
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002077- socket: Support for size hint in readlines() method of object returned
2078 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002079
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002080- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002081 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002082 is followed by whitespace.
2083
Tim Petersa3a3a032000-11-30 05:22:44 +00002084- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002085
2086- struct: Check ranges for bytes and shorts.
2087
2088- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002089 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002090
2091- Tkinter: Image objects are now guaranteed to have unique ids. Set
2092 event.delta to zero if Tk version doesn't support mousewheel.
2093 Removed some debugging prints.
2094
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002095- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002096
Fred Drake67233bc2000-09-26 16:40:27 +00002097- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002098 which works around a bug in Norton AntiVirus 2000 that leads directly
2099 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002100
2101- xml: New version detection code allows PyXML to override standard
2102 XML package if PyXML version is greater than 0.6.1.
2103
Fred Drake64bb3802000-09-26 16:21:35 +00002104- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2105 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2106 tree only for nodes which are sufficiently interesting to a specific
2107 application. Does not provide the HTML-specific extensions. Still
2108 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002109
Fred Drake64bb3802000-09-26 16:21:35 +00002110- xml.sax: SAX 2 support for Python, including all the handler
2111 interfaces needed to process XML 1.0 compliant XML. Some
2112 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002113
Fred Drake64bb3802000-09-26 16:21:35 +00002114- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2115 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002116
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002117
Jeremy Hylton1b618592000-09-26 05:32:36 +00002118C API
2119
2120- Add three new convenience functions for module initialization --
2121 PyModule_AddObject(), PyModule_AddIntConstant(), and
2122 PyModule_AddStringConstant().
2123
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002124- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002125 removed and add #error to Python.h if NULL isn't defined after
2126 #include of stdio.h.
2127
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002128- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002129 backwards compatibility (at the source level) with old extensions.
2130
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002131- A wrapper API was added for signal() and sigaction(). Instead of
2132 either function, always use PyOS_getsig() to get a signal handler
2133 and PyOS_setsig() to set one. A new convenience typedef
2134 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002135
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002136- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002137 internal data buffer and size of a string object -- or the default
2138 encoded version of a Unicode object.
2139
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002140- PyString_Size() and PyString_AsString() accept Unicode objects.
2141
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002142- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002143 exists). INT_MAX and LONG_MAX will always be defined, even if
2144 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002145
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002146- PyFloat_FromString takes a second argument, pend, that was
2147 effectively useless. It is now officially useless but preserved for
2148 backwards compatibility. If the pend argument is not NULL, *pend is
2149 set to NULL.
2150
2151- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2152 for the attribute name. See note on getattr() above.
2153
2154- A few bug fixes to argument processing for Unicode.
2155 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2156 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2157 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002158 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002159
2160- Py_BuildValue accepts B format (for bgen-generated code).
2161
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002162
Jeremy Hylton1b618592000-09-26 05:32:36 +00002163Internals
2164
2165- On Unix, fix code for finding Python installation directory so that
2166 it works when argv[0] is a relative path.
2167
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002168- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002169 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002170 rather than by generating a copy of the object.
2171
Tim Peters482c0212000-09-26 06:33:09 +00002172- Several of the internal Unicode tables are much smaller now, and
2173 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002174
Jeremy Hylton97693b02000-09-26 17:42:51 +00002175- In the garbage collector: Fixed bug in collection of tuples. Fixed
2176 bug that caused some instances to be removed from the container set
2177 while they were still live. Fixed parsing in gc.set_debug() for
2178 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002179
2180- Fixed refcount problem in instance deallocation that only occurred
2181 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2182
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002183- On Windows, getpythonregpath is now protected against null data in
2184 registry key.
2185
2186- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002187 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002188
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002189
Jeremy Hylton1b618592000-09-26 05:32:36 +00002190Build and platform-specific issues
2191
2192- Better support of GNU Pth via --with-pth configure option.
2193
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002194- Python/C API now properly exposed to dynamically-loaded extension
2195 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002196
2197- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2198 Don't define MS_SYNC to be zero when it is undefined. Added missing
2199 prototypes in posixmodule.c.
2200
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002201- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002202 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002203
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002204- Fix largefile support on older NetBSD systems and OpenBSD by adding
2205 define for TELL64.
2206
2207
2208Tools and other miscellany
2209
2210- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2211
2212- freeze: The modulefinder now works with 2.0 opcodes.
2213
Tim Petersa3a3a032000-11-30 05:22:44 +00002214- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002215 Move hackery of sys.argv until after the Tk instance has been
2216 created, which allows the application-specific Tkinter
2217 initialization to be executed if present; also pass an explicit
2218 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002219
Jeremy Hylton1b618592000-09-26 05:32:36 +00002220
2221What's new in 2.0 beta 1?
2222=========================
2223
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002224Source Incompatibilities
2225------------------------
2226
2227None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2228such as single-argument append(), connect() and bind(), and changes to
2229str(long) and repr(float).
2230
2231
2232Binary Incompatibilities
2233------------------------
2234
2235- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2236with Python 2.0; these extensions will have to be rebuilt for Python
22372.0.
2238
2239- On Windows, attempting to import a third party extension built for
2240Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2241can do about this. Check your PYTHONPATH environment variable!
2242
2243- Python bytecode files (*.pyc and *.pyo) are not compatible between
2244releases.
2245
2246
2247Overview of Changes Since 1.6
2248-----------------------------
2249
2250There are many new modules (including brand new XML support through
2251the xml package, and i18n support through the gettext module); a list
2252of all new modules is included below. Lots of bugs have been fixed.
2253
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002254The process for making major new changes to the language has changed
2255since Python 1.6. Enhancements must now be documented by a Python
2256Enhancement Proposal (PEP) before they can be accepted.
2257
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002258There are several important syntax enhancements, described in more
2259detail below:
2260
2261 - Augmented assignment, e.g. x += 1
2262
2263 - List comprehensions, e.g. [x**2 for x in range(10)]
2264
2265 - Extended import statement, e.g. import Module as Name
2266
2267 - Extended print statement, e.g. print >> file, "Hello"
2268
2269Other important changes:
2270
2271 - Optional collection of cyclical garbage
2272
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002273Python Enhancement Proposal (PEP)
2274---------------------------------
2275
2276PEP stands for Python Enhancement Proposal. A PEP is a design
2277document providing information to the Python community, or describing
2278a new feature for Python. The PEP should provide a concise technical
2279specification of the feature and a rationale for the feature.
2280
2281We intend PEPs to be the primary mechanisms for proposing new
2282features, for collecting community input on an issue, and for
2283documenting the design decisions that have gone into Python. The PEP
2284author is responsible for building consensus within the community and
2285documenting dissenting opinions.
2286
2287The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002288
2289Augmented Assignment
2290--------------------
2291
2292This must have been the most-requested feature of the past years!
2293Eleven new assignment operators were added:
2294
Guido van Rossume905e952000-09-05 12:42:46 +00002295 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002296
2297For example,
2298
2299 A += B
2300
2301is similar to
2302
2303 A = A + B
2304
2305except that A is evaluated only once (relevant when A is something
2306like dict[index].attr).
2307
2308However, if A is a mutable object, A may be modified in place. Thus,
2309if A is a number or a string, A += B has the same effect as A = A+B
2310(except A is only evaluated once); but if a is a list, A += B has the
2311same effect as A.extend(B)!
2312
2313Classes and built-in object types can override the new operators in
2314order to implement the in-place behavior; the not-in-place behavior is
2315used automatically as a fallback when an object doesn't implement the
2316in-place behavior. For classes, the method name is derived from the
2317method name for the corresponding not-in-place operator by inserting
2318an 'i' in front of the name, e.g. __iadd__ implements in-place
2319__add__.
2320
2321Augmented assignment was implemented by Thomas Wouters.
2322
2323
2324List Comprehensions
2325-------------------
2326
2327This is a flexible new notation for lists whose elements are computed
2328from another list (or lists). The simplest form is:
2329
2330 [<expression> for <variable> in <sequence>]
2331
Guido van Rossum56db0952000-09-06 23:34:25 +00002332For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002333This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002334
2335You can also add a condition:
2336
2337 [<expression> for <variable> in <sequence> if <condition>]
2338
2339For example, [w for w in words if w == w.lower()] would yield the list
2340of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002341than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002342
2343You can also have nested for loops and more than one 'if' clause. For
2344example, here's a function that flattens a sequence of sequences::
2345
2346 def flatten(seq):
2347 return [x for subseq in seq for x in subseq]
2348
2349 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2350
2351This prints
2352
2353 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2354
2355List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002356Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002357
2358
2359Extended Import Statement
2360-------------------------
2361
2362Many people have asked for a way to import a module under a different
2363name. This can be accomplished like this:
2364
2365 import foo
2366 bar = foo
2367 del foo
2368
2369but this common idiom gets old quickly. A simple extension of the
2370import statement now allows this to be written as follows:
2371
2372 import foo as bar
2373
2374There's also a variant for 'from ... import':
2375
2376 from foo import bar as spam
2377
2378This also works with packages; e.g. you can write this:
2379
2380 import test.regrtest as regrtest
2381
2382Note that 'as' is not a new keyword -- it is recognized only in this
2383context (this is only possible because the syntax for the import
2384statement doesn't involve expressions).
2385
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002386Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002387
2388
2389Extended Print Statement
2390------------------------
2391
2392Easily the most controversial new feature, this extension to the print
2393statement adds an option to make the output go to a different file
2394than the default sys.stdout.
2395
2396For example, to write an error message to sys.stderr, you can now
2397write:
2398
2399 print >> sys.stderr, "Error: bad dog!"
2400
2401As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002402evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002403
2404 print >> None, "Hello world"
2405
2406is equivalent to
2407
2408 print "Hello world"
2409
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002410Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002411
2412
2413Optional Collection of Cyclical Garbage
2414---------------------------------------
2415
2416Python is now equipped with a garbage collector that can hunt down
2417cyclical references between Python objects. It's no replacement for
2418reference counting; in fact, it depends on the reference counts being
2419correct, and decides that a set of objects belong to a cycle if all
2420their reference counts can be accounted for from their references to
2421each other. This devious scheme was first proposed by Eric Tiedemann,
2422and brought to implementation by Neil Schemenauer.
2423
2424There's a module "gc" that lets you control some parameters of the
2425garbage collection. There's also an option to the configure script
2426that lets you enable or disable the garbage collection. In 2.0b1,
2427it's on by default, so that we (hopefully) can collect decent user
2428experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002429performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002430off by default in the final 2.0 release.
2431
2432
2433Smaller Changes
2434---------------
2435
2436A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2437map(None, seq1, seq2, ...) when the sequences have the same length;
2438i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2439the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002440zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002441
2442sys.version_info is a tuple (major, minor, micro, level, serial).
2443
2444Dictionaries have an odd new method, setdefault(key, default).
2445dict.setdefault(key, default) returns dict[key] if it exists; if not,
2446it sets dict[key] to default and returns that value. Thus:
2447
2448 dict.setdefault(key, []).append(item)
2449
2450does the same work as this common idiom:
2451
2452 if not dict.has_key(key):
2453 dict[key] = []
2454 dict[key].append(item)
2455
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002456There are two new variants of SyntaxError that are raised for
2457indentation-related errors: IndentationError and TabError.
2458
2459Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2460escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002461
2462The limits on the size of expressions and file in Python source code
2463have been raised from 2**16 to 2**32. Previous versions of Python
2464were limited because the maximum argument size the Python VM accepted
2465was 2**16. This limited the size of object constructor expressions,
2466e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2467limit was raised thanks to a patch by Charles Waldman that effectively
2468fixes the problem. It is now much more likely that you will be
2469limited by available memory than by an arbitrary limit in Python.
2470
2471The interpreter's maximum recursion depth can be modified by Python
2472programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2473limit is the maximum number of recursive calls that can be made by
2474Python code. The limit exists to prevent infinite recursion from
2475overflowing the C stack and causing a core dump. The default value is
24761000. The maximum safe value for a particular platform can be found
2477by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002478
2479New Modules and Packages
2480------------------------
2481
2482atexit - for registering functions to be called when Python exits.
2483
2484imputil - Greg Stein's alternative API for writing custom import
2485hooks.
2486
2487pyexpat - an interface to the Expat XML parser, contributed by Paul
2488Prescod.
2489
2490xml - a new package with XML support code organized (so far) in three
2491subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2492would fill a volume. There's a special feature whereby a
2493user-installed package named _xmlplus overrides the standard
2494xmlpackage; this is intended to give the XML SIG a hook to distribute
2495backwards-compatible updates to the standard xml package.
2496
2497webbrowser - a platform-independent API to launch a web browser.
2498
2499
Guido van Rossume905e952000-09-05 12:42:46 +00002500Changed Modules
2501---------------
2502
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002503array -- new methods for array objects: count, extend, index, pop, and
2504remove
2505
2506binascii -- new functions b2a_hex and a2b_hex that convert between
2507binary data and its hex representation
2508
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002509calendar -- Many new functions that support features including control
2510over which day of the week is the first day, returning strings instead
2511of printing them. Also new symbolic constants for days of week,
2512e.g. MONDAY, ..., SUNDAY.
2513
2514cgi -- FieldStorage objects have a getvalue method that works like a
2515dictionary's get method and returns the value attribute of the object.
2516
2517ConfigParser -- The parser object has new methods has_option,
2518remove_section, remove_option, set, and write. They allow the module
2519to be used for writing config files as well as reading them.
2520
2521ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002522optionally support the RFC 959 REST command.
2523
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002524gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002525
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002526httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2527the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002528
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002529locale -- implement getdefaultlocale for Win32 and Macintosh
2530
2531marshal -- no longer dumps core when marshaling deeply nested or
2532recursive data structures
2533
2534os -- new functions isatty, seteuid, setegid, setreuid, setregid
2535
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002536os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2537support under Unix.
2538
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002539os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002540
2541os.path -- fix semantics of os.path.commonprefix
2542
2543smtplib -- support for sending very long messages
2544
2545socket -- new function getfqdn()
2546
2547readline -- new functions to read, write and truncate history files.
2548The readline section of the library reference manual contains an
2549example.
2550
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002551select -- add interface to poll system call
2552
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002553shutil -- new copyfileobj function
2554
2555SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2556HTTP server.
2557
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002558Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002559
2560urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002561e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002562
2563whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002564
2565
2566Obsolete Modules
2567----------------
2568
2569None. However note that 1.6 made a whole slew of modules obsolete:
2570stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2571poly, zmod, strop, util, whatsound.
2572
2573
2574Changed, New, Obsolete Tools
2575----------------------------
2576
Tim Peters8b092332000-09-05 20:15:25 +00002577None.
Guido van Rossume905e952000-09-05 12:42:46 +00002578
2579
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002580C-level Changes
2581---------------
2582
2583Several cleanup jobs were carried out throughout the source code.
2584
2585All C code was converted to ANSI C; we got rid of all uses of the
2586Py_PROTO() macro, which makes the header files a lot more readable.
2587
2588Most of the portability hacks were moved to a new header file,
2589pyport.h; several other new header files were added and some old
2590header files were removed, in an attempt to create a more rational set
2591of header files. (Few of these ever need to be included explicitly;
2592they are all included by Python.h.)
2593
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002594Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002595and Win64, especially for the new Intel Itanium processor. Mick also
2596added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002597
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002598The C APIs to return an object's size have been update to consistently
2599use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2600previous versions, the abstract interfaces used PyXXX_Length and the
2601concrete interfaces used PyXXX_Size. The old names,
2602e.g. PyObject_Length, are still available for backwards compatibility
2603at the API level, but are deprecated.
2604
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002605The PyOS_CheckStack function has been implemented on Windows by
2606Fredrik Lundh. It prevents Python from failing with a stack overflow
2607on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002608
2609The GC changes resulted in creation of two new slots on object,
2610tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002611the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002612
2613The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002614C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002615
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002616PyErr_Format has been updated to automatically calculate the size of
2617the buffer needed to hold the formatted result string. This change
2618prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002619
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002620New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002621
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002622PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2623that are the same as their non-Ex counterparts except they take an
2624extra flag argument that tells them to close the file when done.
2625
2626XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002627
Tim Peters8b092332000-09-05 20:15:25 +00002628
2629Windows Changes
2630---------------
2631
2632New popen2/popen3/peopen4 in os module (see Changed Modules above).
2633
2634os.popen is much more usable on Windows 95 and 98. See Microsoft
2635Knowledge Base article Q150956. The Win9x workaround described there
2636is implemented by the new w9xpopen.exe helper in the root of your
2637Python installation. Note that Python uses this internally; it is not
2638a standalone program.
2639
2640Administrator privileges are no longer required to install Python
2641on Windows NT or Windows 2000. If you have administrator privileges,
2642Python's registry info will be written under HKEY_LOCAL_MACHINE.
2643Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002644under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002645uses of Python, but will prevent some advanced uses from working
2646(for example, running a Python script as an NT service, or possibly
2647from CGI).
2648
2649[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2650installer; instead, it installs the needed Tcl/Tk files directly in the
2651Python directory. If you already have a Tcl/Tk installation, this
2652wastes some disk space (about 4 Megs) but avoids problems with
2653conflicting Tcl/Tk installations, and makes it much easier for Python
2654to ensure that Tcl/Tk can find all its files.
2655
2656[This was new in 1.6] The Windows installer now installs by default in
2657\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2658
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002659
2660Updates to the changes between 1.5.2 and 1.6
2661--------------------------------------------
2662
2663The 1.6 NEWS file can't be changed after the release is done, so here
2664is some late-breaking news:
2665
2666New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2667and changes to getlocale() and setlocale().
2668
2669The new module is now enabled per default.
2670
2671It is not true that the encodings codecs cannot be used for normal
2672strings: the string.encode() (which is also present on 8-bit strings
2673!) allows using them for 8-bit strings too, e.g. to convert files from
2674cp1252 (Windows) to latin-1 or vice-versa.
2675
2676Japanese codecs are available from Tamito KAJIYAMA:
2677http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2678
2679
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002680======================================================================