blob: 1e95283043fbbed96d53280b51b22f0ff87a433d [file] [log] [blame]
Tim Petersabf925f2001-09-28 21:53:42 +00001What's New in Python 2.2b1?
2Release date: 28-Sep-2100
3===========================
4
5Type/class unification and new-style classes
6
Guido van Rossum687ae002001-10-15 22:03:32 +00007- New-style classes are now always dynamic (except for built-in and
8 extension types). There was no longer a performance penalty, and I
9 no longer see another reason to keep this baggage around. One relic
10 remains: the __dict__ or a new-style class is a read-only proxy.
11 You must set the class's attribute to modify. As a consequence, the
12 __defined__ attribute of new-style types no longer exists, for lack
13 of need: there is once again only one __dict__ (although in the
14 future a __cache__ may be resurrected in its place).
Guido van Rossum50fda3b2001-10-04 19:46:06 +000015
Tim Peters1c9ca872001-10-04 06:43:12 +000016- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
17 always returned None, even when there was a class docstring).
18
19- doctest now finds and runs docstrings attached to new-style classes,
20 class methods, static methods, and properties.
21
Tim Petersabf925f2001-09-28 21:53:42 +000022Core
23
Guido van Rossuma8bcf802001-10-15 15:53:58 +000024- A very subtle syntactical pitfall in list comprehensions was fixed.
25 For example: [a+b for a in 'abc', for b in 'def']. The comma in
26 this example is a mistake. Previously, this would silently let 'a'
27 iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
28 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
29 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
30 Note that [a for a in <singleton>] is a convoluted way to say
31 [<singleton>] anyway, so it's not like any expressiveness is lost.
32
Martin v. Löwis16dc7f42001-09-30 20:32:11 +000033- binascii has now two quopri support functions, a2b_qp and b2a_qp.
34
Martin v. Löwis0daad592001-09-30 21:09:59 +000035- readline now supports setting the startup_hook and the pre_event_hook.
36
Martin v. Löwis16628c92001-10-04 22:46:41 +000037- posix supports chroot where available.
38
Tim Petersabf925f2001-09-28 21:53:42 +000039Library
40
Tim Peters7402f792001-10-02 03:53:41 +000041- doctest now excludes functions and classes not defined by the module
42 being tested, thanks to Tim Hochberg.
43
Guido van Rossumc4b09b42001-10-04 10:19:00 +000044- profile now produces correct output in situations where an exception
45 raised in Python is cleared by C code (e.g. hasattr()). This used
46 to cause wrong output, including spurious claims of recursive
47 functions and attribution of time spent to the wrong function.
48
Tim Peters0a1fc4e2001-10-07 03:12:08 +000049 The code and documentation for the derived OldProfile and HotProfile
50 profiling classes was removed. The code hasn't worked for years (if
51 you tried to use them, they raised exceptions). OldProfile
52 intended to reproduce the behavior of the profiler Python used more
53 than 7 years ago, and isn't interesting anymore. HotProfile intended
54 to provide a faster profiler (but producing less information), and
55 that's a worthy goal we intend to meet via a different approach (but
56 without losing information).
57
Tim Peterscce092d2001-10-09 05:31:56 +000058- Profile.calibrate() has a new implementation that should deliver
Tim Peters659a6032001-10-09 20:51:19 +000059 a much better system-specific calibration constant. The constant can
60 now be specified in an instance constructor, or as a Profile class or
61 instance variable, instead of by editing profile.py's source code.
62 Calibration must still be done manually (see the docs for the profile
63 module).
64
65 Note that Profile.calibrate() must be overriden by subclasses.
66 Improving the accuracy required exploiting detailed knowledge of
67 profiler internals; the earlier method abstracted away the details
68 and measured a simplified model instead, but consequently computed
69 a constant too small by a factor of 2 on some modern machines.
Tim Peterscce092d2001-10-09 05:31:56 +000070
Martin v. Löwis16dc7f42001-09-30 20:32:11 +000071- quopri's encode and decode methods take an optional header parameter,
72 which indicates whether output is intended for the header 'Q' encoding.
73
Guido van Rossumed554f62001-10-02 23:15:37 +000074Tools/Demos
75
76- Demo/dns was removed. It no longer serves any purpose; a package
77 derived from it is now maintained by Anthony Baxter, see
78 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +000079
80Build
81
82C API
83
Tim Petersd38b1c72001-09-30 05:09:37 +000084- PyLong_AsLongLong() now accepts int (as well as long) arguments.
85 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
86 as long) arguments.
87
Tim Petersabf925f2001-09-28 21:53:42 +000088New platforms
89
90Tests
91
92Windows
93
Tim Peters04cf1d32001-10-09 22:39:40 +000094- Installer: If you install IDLE, and don't disable file-extension
95 registration, a new "Edit with IDLE" context (right-click) menu entry
96 is created for .py and .pyw files.
97
Tim Peters1ce3cf72001-10-01 17:58:40 +000098- The signal module now supports SIGBREAK on Windows, thanks to Steven
99 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
100 action remains to call Win32 ExitProcess(). This can be changed via
101 signal.signal(). For example:
102
103 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
104 # (SIGINT) behavior.
105 import signal
106 signal.signal(signal.SIGBREAK,
107 signal.default_int_handler)
108
109 try:
110 while 1:
111 pass
112 except KeyboardInterrupt:
113 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
114 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
115 # program without the possibility for any Python-level cleanup).
116 print "Clean exit"
117
Tim Petersabf925f2001-09-28 21:53:42 +0000118
Tim Petersb07352e2001-09-08 01:25:47 +0000119What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000120Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000121===========================
122
Guido van Rossum808eea72001-09-25 04:15:41 +0000123Type/class unification and new-style classes
124
125- pydoc and inspect are now aware of new-style classes;
126 e.g. help(list) at the interactive prompt now shows proper
127 documentation for all operations on list objects.
128
129- Applications using Jim Fulton's ExtensionClass module can now safely
130 be used with Python 2.2. In particular, Zope 2.4.1 now works with
131 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
132 examples also work again. It is hoped that Gtk and Boost also work
133 with 2.2a4 and beyond. (If you can confirm this, please write
134 webmaster@python.org; if there are still problems, please open a bug
135 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000136
Tim Peters66c1a522001-09-24 21:17:50 +0000137- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
138 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
139 in the constructed property object. fget, fset and fdel weren't
140 discoverable from Python in 2.2a3. __doc__ is new, and allows to
141 associate a docstring with a property.
142
Guido van Rossum808eea72001-09-25 04:15:41 +0000143- Comparison overloading is now more completely implemented. For
144 example, a str subclass instance can properly be compared to a str
145 instance, and it can properly overload comparison. Ditto for most
146 other built-in object types.
147
148- The repr() of new-style classes has changed; instead of <type
149 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
150 *except* for built-in types, which are still rendered as <type
151 'Foo'> (to avoid upsetting existing code that might parse or
152 otherwise rely on repr() of certain type objects).
153
154- The repr() of new-style objects is now always <Foo object at XXX>;
155 previously, it was sometimes <Foo instance at XXX>.
156
157- For new-style classes, what was previously called __getattr__ is now
158 called __getattribute__. This method, if defined, is called for
159 *every* attribute access. A new __getattr__ hook mor similar to the
160 one in classic classes is defined which is called only if regular
161 attribute access raises AttributeError; to catch *all* attribute
162 access, you can use __getattribute__ (for new-style classes). If
163 both are defined, __getattribute__ is called first, and if it raises
164 AttributeError, __getattr__ is called.
165
166- The __class__ attribute of new-style objects can be assigned to.
167 The new class must have the same C-level object layout as the old
168 class.
169
170- The builtin file type can be subclassed now. In the usual pattern,
171 "file" is the name of the builtin type, and file() is a new builtin
172 constructor, with the same signature as the builtin open() function.
173 file() is now the preferred way to open a file.
174
175- Previously, __new__ would only see sequential arguments passed to
176 the type in a constructor call; __init__ would see both sequential
177 and keyword arguments. This made no sense whatsoever any more, so
178 now both __new__ and __init__ see all arguments.
179
180- Previously, hash() applied to an instance of a subclass of str or
181 unicode always returned 0. This has been repaired.
182
183- Previously, an operation on an instance of a subclass of an
184 immutable type (int, long, float, complex, tuple, str, unicode),
185 where the subtype didn't override the operation (and so the
186 operation was handled by the builtin type), could return that
187 instance instead a value of the base type. For example, if s was of
188 a str sublass type, s[:] returned s as-is. Now it returns a str
189 with the same value as s.
190
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000191- Provisional support for pickling new-style objects has been added.
192
Guido van Rossum808eea72001-09-25 04:15:41 +0000193Core
194
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000195- file.writelines() now accepts any iterable object producing strings.
196
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000197- PyUnicode_FromEncodedObject() now works very much like
198 PyObject_Str(obj) in that it tries to use __str__/tp_str
199 on the object if the object is not a string or buffer. This
200 makes unicode() behave like str() when applied to non-string/buffer
201 objects.
202
Martin v. Löwis2777c022001-09-19 13:47:32 +0000203- PyFile_WriteObject now passes Unicode object to the file's write
204 method. As a result, all file-like object which may be the target
205 of a print statement must support Unicode objects, i.e. they must
206 at least convert them into ASCII strings.
207
Guido van Rossum624c8af2001-09-18 15:21:04 +0000208- Thread scheduling on Solaris should be improved; it is no longer
209 necessary to insert a small sleep at the start of a thread in order
210 to let other runnable threads be scheduled.
211
Tim Petersb07352e2001-09-08 01:25:47 +0000212Library
213
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000214- StringIO.StringIO instances and cStringIO.StringIO instances support
215 read character buffer compatible objects for their .write() methods.
216 These objects are converted to strings and then handled as such
217 by the instances.
218
Barry Warsaw2f600732001-09-24 04:28:10 +0000219- The "email" package has been added. This is basically a port of the
220 mimelib package <http://sf.net/projects/mimelib> with API changes
221 and some implementations updated to use iterators and generators.
222
Tim Peters8a9c2842001-09-22 21:30:22 +0000223- difflib.ndiff() and difflib.Differ.compare() are generators now. This
224 restores the ability of Tools/scripts/ndiff.py to start producing output
225 before the entire comparison is complete.
226
Barry Warsaw58b072d2001-09-22 04:44:21 +0000227- StringIO.StringIO instances and cStringIO.StringIO instances support
228 iteration just like file objects (i.e. their .readline() method is
229 called for each iteration until it returns an empty string).
230
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000231- The codecs module has grown four new helper APIs to access
232 builtin codecs: getencoder(), getdecoder(), getreader(),
233 getwriter().
234
Guido van Rossum624c8af2001-09-18 15:21:04 +0000235- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
236 simplifies writing XML RPC servers.
237
Barry Warsaw647d5e82001-09-28 17:01:02 +0000238- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000239 after interpretation of symbolic links. On non-Unix systems, this
240 is an alias for os.path.abspath().
241
Tim Peters16a77ad2001-09-08 04:00:12 +0000242- operator.indexOf() (PySequence_Index() in the C API) now works with any
243 iterable object.
244
Guido van Rossum624c8af2001-09-18 15:21:04 +0000245- smtplib now supports various authentication and security features of
246 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000247
Guido van Rossum624c8af2001-09-18 15:21:04 +0000248- hmac: a new module implementing keyed hashing for message
249 authentication.
250
251- mimetypes now recognizes more extensions and file types. At the
252 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000253
Guido van Rossum624c8af2001-09-18 15:21:04 +0000254- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000255 Python 2.2 bytecode generation. It has also been promoted from a
256 Tool to a standard library package. (Tools/compiler still exists as
257 a sample driver.)
258
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000259Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000260
Tim Petersb07352e2001-09-08 01:25:47 +0000261Build
262
Guido van Rossum624c8af2001-09-18 15:21:04 +0000263- Large file support (LFS) is now automatic when the platform supports
264 it; no more manual configuration tweaks are needed. On Linux, at
265 least, it's possible to have a system whose C library supports large
266 files but whose kernel doesn't; in this case, large file support is
267 still enabled but doesn't do you any good unless you upgrade your
268 kernel or share your Python executable with another system whose
269 kernel has large file support.
270
271- The configure script now supplies plausible defaults in a
272 cross-compilation environment. This doesn't mean that the supplied
273 values are always correct, or that cross-compilation now works
274 flawlessly -- but it's a first step (and it shuts up most of
275 autoconf's warnings about AC_TRY_RUN).
276
277- The Unix build is now a bit less chatty, courtesy of the parser
278 generator. The build is completely silent (except for errors) when
279 using "make -s", thanks to a -q option to setup.py.
280
Tim Petersb07352e2001-09-08 01:25:47 +0000281C API
282
Guido van Rossum624c8af2001-09-18 15:21:04 +0000283- The "structmember" API now supports some new flag bits to deny read
284 and/or write access to attributes in restricted execution mode.
285
Tim Petersb07352e2001-09-08 01:25:47 +0000286New platforms
287
Guido van Rossum624c8af2001-09-18 15:21:04 +0000288- Compaq's iPAQ handheld, running the "familiar" Linux distribution
289 (http://familiar.handhelds.org).
290
Tim Petersb07352e2001-09-08 01:25:47 +0000291Tests
292
Tim Peters8a9c2842001-09-22 21:30:22 +0000293- The "classic" standard tests, which work by comparing stdout to
294 an expected-output file under Lib/test/output/, no longer stop at
295 the first mismatch. Instead the test is run to completion, and a
296 variant of ndiff-style comparison is used to report all differences.
297 This is much easier to understand than the previous style of reporting.
298
299- The unittest-based standard tests now use regrtest's test_main()
300 convention, instead of running as a side-effect of merely being
301 imported. This allows these tests to be run in more natural and
302 flexible ways as unittests, outside the regrtest framework.
303
304- regrtest.py is much better integrated with unittest and doctest now,
305 especially in regard to reporting errors.
306
Tim Petersb07352e2001-09-08 01:25:47 +0000307Windows
308
Guido van Rossum624c8af2001-09-18 15:21:04 +0000309- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000310 that support it (NTFS under Windows 2000). See "What's New in
311 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000312
Tim Petersb07352e2001-09-08 01:25:47 +0000313
Tim Petersedc99312001-08-22 21:36:50 +0000314What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000315Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000316===========================
317
318Core
319
Tim Peters9fffa3e2001-09-04 05:14:19 +0000320- Conversion of long to float now raises OverflowError if the long is too
321 big to represent as a C double.
322
Tim Peters32f453e2001-09-03 08:35:41 +0000323- The 3-argument builtin pow() no longer allows a third non-None argument
324 if either of the first two arguments is a float, or if both are of
325 integer types and the second argument is negative (in which latter case
326 the arguments are converted to float, so this is really the same
327 restriction).
328
Tim Peters5d2b77c2001-09-03 05:47:38 +0000329- The builtin dir() now returns more information, and sometimes much
330 more, generally naming all attributes of an object, and all attributes
331 reachable from the object via its class, and from its class's base
332 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
333 an empty list. In 2.2a3,
334
335 >>> dir([])
336 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
337 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
338 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
339 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
340 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
341 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
342 'reverse', 'sort']
343
344 dir(module) continues to return only the module's attributes, though.
345
Tim Petersbdee63f2001-09-02 03:40:59 +0000346- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000347 than raising OverflowError. This is a partial implementation of PEP
348 237. You can use -Wdefault::OverflowWarning to enable a warning for
349 this situation, and -Werror::OverflowWarning to revert to the old
350 OverflowError exception.
351
Guido van Rossum61c345f2001-09-04 03:26:15 +0000352- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000353 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000354 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
355 -Qold, meaning the / operator has its classic meaning and no
356 warnings are issued. Using -Qwarn issues a run-time warning about
357 all uses of classic division for int and long arguments; -Qwarnall
358 also warns about classic division for float and complex arguments
359 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
360 new division by default, but only in the __main__ module. You can
361 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
362 __main__ module new division, and warns about classic division
363 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000364
Tim Petersbdee63f2001-09-02 03:40:59 +0000365- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000366 long, float, str, unicode, and tuple. (The types complex, list and
367 dictionary can also be subclassed; this was introduced earlier.)
368 Note that restrictions apply when subclassing immutable built-in
369 types: you can only affect the value of the instance by overloading
370 __new__. You can add mutable attributes, and the subclass instances
371 will have a __dict__ attribute, but you cannot change the "value"
372 (as implemented by the base class) of an immutable subclass instance
373 once it is created.
374
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000375- The dictionary constructor now takes an optional argument, a
376 mapping-like object, and initializes the dictionary from its
377 (key, value) pairs.
378
Tim Petersbdee63f2001-09-02 03:40:59 +0000379- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000380 "cooperative super calls" in a multiple inheritance setting. For an
381 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
382
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000383- A new built-in type, property, has been added. This enables the
384 creation of "properties". These are attributes implemented by
385 getter and setter functions (or only one of these for read-only or
386 write-only attributes), without the need to override __getattr__.
387 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000388
Tim Petersbdee63f2001-09-02 03:40:59 +0000389- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000390 liberalized, to allow leading zeroes. Examples of literals now
391 legal that were SyntaxErrors before:
392
393 00.0 0e3 0100j 07.5 00000000000000000008.
394
Tim Petersbdee63f2001-09-02 03:40:59 +0000395- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000396 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
397
Tim Petersedc99312001-08-22 21:36:50 +0000398Library
399
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000400- telnetlib includes symbolic names for the options, and support for
401 setting an option negotiation callback.
402
Tim Petersa40c7932001-09-05 22:36:56 +0000403- The new C standard no longer requires that math libraries set errno to
404 ERANGE on overflow. For platform libraries that exploit this new
405 freedom, Python's overflow-checking was wholly broken. A new overflow-
406 checking scheme attempts to repair that, but may not be reliable on all
407 platforms (C doesn't seem to provide anything both useful and portable
408 in this area anymore).
409
Martin v. Löwis44f86962001-09-05 13:44:54 +0000410- Asynchronous timeout actions are available through the new class
411 threading.Timer.
412
Tim Peters78526162001-09-05 00:53:45 +0000413- math.log and math.log10 now return sensible results for even huge
414 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
415
Tim Petersbdee63f2001-09-02 03:40:59 +0000416- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000417 currently held. See the docs for the imp module.
418
Tim Petersbdee63f2001-09-02 03:40:59 +0000419- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000420 dumps containing ints written on platforms where Python ints are 8 bytes.
421 When read on a box where Python ints are 4 bytes, such values are
422 converted to Python longs.
423
Tim Petersbdee63f2001-09-02 03:40:59 +0000424- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000425 code objects is no longer allowed. This plugs a security hole.
426
Steve Purcell6091cd62001-09-06 16:05:17 +0000427- unittest.TestResult instances no longer store references to tracebacks
428 generated by test failures. This prevents unexpected dangling references
429 to objects that should be garbage collected between tests.
430
Tim Petersedc99312001-08-22 21:36:50 +0000431Tools
432
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000433- Tools/scripts/fixdiv.py has been added which can be used to fix
434 division operators as per PEP 238.
435
Tim Petersedc99312001-08-22 21:36:50 +0000436Build
437
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000438- If you are an adventurous person using Mac OS X you may want to look at
439 Mac/OSX. There is a Makefile there that will build Python as a real Mac
440 application, which can be used for experimenting with Carbon or Cocoa.
441 Discussion of this on pythonmac-sig, please.
442
Tim Peters7eea37e2001-09-04 22:08:56 +0000443C API
444
445- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000446
Tim Peters9fffa3e2001-09-04 05:14:19 +0000447- Note that PyLong_AsDouble can fail! This has always been true, but no
448 callers checked for it. It's more likely to fail now, because overflow
449 errors are properly detected now. The proper way to check:
450
451 double x = PyLong_AsDouble(some_long_object);
452 if (x == -1.0 && PyErr_Occurred()) {
453 /* The conversion failed. */
454 }
455
Tim Petersbdee63f2001-09-02 03:40:59 +0000456- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000457 compile but will not participate in GC. To upgrade an extension
458 module:
459
460 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000461
Neil Schemenauer4042c692001-08-30 15:38:01 +0000462 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
463 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000464
Neil Schemenauer4042c692001-08-30 15:38:01 +0000465 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
466 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000467
Neil Schemenauer4042c692001-08-30 15:38:01 +0000468 - remove PyGC_HEAD_SIZE from object size calculations
469
470 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
471
Tim Petersbdee63f2001-09-02 03:40:59 +0000472- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000473 These can be used safely to construct string objects from a
474 sprintf-style format string (similar to the format string supported
475 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000476
Tim Petersedc99312001-08-22 21:36:50 +0000477New platforms
478
Tim Petersb7da0902001-09-02 23:01:43 +0000479- Stephen Hansen contributed patches sufficient to get a clean compile
480 under Borland C (Windows), but he reports problems running it and ran
481 out of time to complete the port. Volunteers? Expect a MemoryError
482 when importing the types module; this is probably shallow, and
483 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000484
Tim Petersedc99312001-08-22 21:36:50 +0000485Tests
486
487Windows
488
Tim Peters6e13a562001-09-06 00:32:15 +0000489- Large file support is now enabled on Win32 platforms as well as on
490 Win64. This means that, for example, you can use f.tell() and f.seek()
491 to manipulate files larger than 2 gigabytes (provided you have enough
492 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000493 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
494 filesize limit, and large file support makes no difference there.
495 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
496 NTFS has no practical limit on file size, and files of any size can be
497 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000498
Tim Petersbdee63f2001-09-02 03:40:59 +0000499- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000500 points to command.com (patch from Brian Quinlan).
501
Tim Petersedc99312001-08-22 21:36:50 +0000502
Tim Peters20f51a72001-07-21 02:31:40 +0000503What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000504Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000505===========================
506
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000507Build
508
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000509- Tim Peters developed a brand new Windows installer using Wise 8.1,
510 generously donated to us by Wise Solutions.
511
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000512- configure supports a new option --enable-unicode, with the values
513 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
514 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000515
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000516- A new configure option --enable-framework builds a Mac OS X framework,
517 which "make frameworkinstall" will install. This provides a starting
518 point for more mac-like functionality, join pythonmac-sig@python.org
519 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000520
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000521- The NeXT platform is no longer supported.
522
523- The `new' module is now statically linked.
524
Tim Peters0afb6092001-08-15 06:06:44 +0000525Tools
526
527- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000528 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000529 the module docstring for details.
530
Tim Peters20f51a72001-07-21 02:31:40 +0000531Tests
532
Tim Peters5e824c32001-08-12 22:25:01 +0000533- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000534 platforms, allowing to give clearer test result output. regrtest
535 also has optional --use/-u switch to run normally disabled tests
536 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000537
Tim Peters20f51a72001-07-21 02:31:40 +0000538- Several new tests in the standard test suite, with special thanks to
539 Nick Mathewson.
540
541Core
542
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000543- The floor division operator // has been added as outlined in PEP
544 238. The / operator still provides classic division (and will until
545 Python 3.0) unless "from __future__ import division" is included, in
546 which case the / operator will provide true division. The operator
547 module provides truediv() and floordiv() functions. Augmented
548 assignment variants are included, as are the equivalent overloadable
549 methods and C API methods. See the PEP for a full discussion:
550 <http://python.sf.net/peps/pep-0238.html>
551
Tim Peters6cd6a822001-08-17 22:11:27 +0000552- Future statements are now effective in simulated interactive shells
553 (like IDLE). This should "just work" by magic, but read Michael
554 Hudson's "Future statements in simulated shells" PEP 264 for full
555 details: <http://python.sf.net/peps/pep-0264.html>.
556
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000557- The type/class unification (PEP 252-253) was integrated into the
558 trunk and is not so tentative any more (the exact specification of
559 some features is still tentative). A lot of work has done on fixing
560 bugs and adding robustness and features (performance still has to
561 come a long way).
562
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000563- Warnings about a mismatch in the Python API during extension import
564 now use the Python warning framework (which makes it possible to
565 write filters for these warnings).
566
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000567- A function's __dict__ (aka func_dict) will now always be a
568 dictionary. It used to be possible to delete it or set it to None,
569 but now both actions raise TypeErrors. It is still legal to set it
570 to a dictionary object. Getting func.__dict__ before any attributes
571 have been assigned now returns an empty dictionary instead of None.
572
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000573- A new command line option, -E, was added which disables the use of
574 all environment variables, or at least those that are specifically
575 significant to Python. Usually those have a name starting with
576 "PYTHON". This was used to fix a problem where the tests fail if
577 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
578 older distribution.
579
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000580Library
581
Tim Peters5e824c32001-08-12 22:25:01 +0000582- New class Differ and new functions ndiff() and restore() in difflib.py.
583 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000584 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000585
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000586- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
587 value using the minimal quoting required for the value; more
588 reliable than using xml.sax.saxutils.escape() for attribute values.
589
590- Readline completion support for cmd.Cmd was added.
591
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000592- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
593
594- Added function threading.BoundedSemaphore()
595
596- Added Ka-Ping Yee's cgitb.py module.
597
598- The `new' module now exposes the CO_xxx flags.
599
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000600New platforms
601
602C API
603
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000604- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
605 which provide a cross-platform implementations for the
606 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
607 the standard sprintf() and vsprintf() C lib APIs, these versions
608 apply bounds checking on the used buffer which enhances protection
609 against buffer overruns.
610
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000611- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000612 and extensions using different Unicode widths is rendered next to
613 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000614 will result in an ImportError. Unicode extensions writers must make
615 sure to check the Unicode width compatibility in their extensions by
616 using at least one of the mangled Unicode APIs in the extension.
617
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000618- Two new flags METH_NOARGS and METH_O are available in method definition
619 tables to simplify implementation of methods with no arguments and a
620 single untyped argument. Calling such methods is more efficient than
621 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
622 deprecated.
623
Tim Petersc1731372001-08-04 08:12:36 +0000624Windows
625
626- "import module" now compiles module.pyw if it exists and nothing else
627 relevant is found.
628
Tim Peters20f51a72001-07-21 02:31:40 +0000629
Guido van Rossum55a78992001-07-17 17:22:32 +0000630What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +0000631===========================
632
633Core
Tim Petersa814db52001-05-14 07:05:58 +0000634
Tim Peters6d6c1a32001-08-02 04:15:00 +0000635- TENTATIVELY, a large amount of code implementing much of what's
636 described in PEP 252 (Making Types Look More Like Classes) and PEP
637 253 (Subtyping Built-in Types) was added. This will be released
638 with Python 2.2a1. Documentation will be provided separately
639 through http://www.python.org/2.2/. The purpose of releasing this
640 with Python 2.2a1 is to test backwards compatibility. It is
641 possible, though not likely, that a decision is made not to release
642 this code as part of 2.2 final, if any serious backwards
643 incompapatibilities are found during alpha testing that cannot be
644 repaired.
645
Guido van Rossum55a78992001-07-17 17:22:32 +0000646- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000647 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000648 more 'yield' statements. See PEP 255. Since this adds a new
649 keyword to the language, this feature must be enabled by including a
650 future statement: "from __future__ import generators" (see PEP 236).
651 Generators will become a standard feature in a future release
652 (probably 2.3). Without this future statement, 'yield' remains an
653 ordinary identifier, but a warning is issued each time it is used.
654 (These warnings currently don't conform to the warnings framework of
655 PEP 230; we intend to fix this in 2.2a2.)
656
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000657- The UTF-16 codec was modified to be more RFC compliant. It will now
658 only remove BOM characters at the start of the string and then
659 only if running in native mode (UTF-16-LE and -BE won't remove a
660 leading BMO character).
661
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000662- Strings now have a new method .decode() to complement the already
663 existing .encode() method. These two methods provide direct access
664 to the corresponding decoders and encoders of the registered codecs.
665
666 To enhance the usability of the .encode() method, the special
667 casing of Unicode object return values was dropped (Unicode objects
668 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000669
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000670 Both methods will now return whatever the codec in charge of the
671 requested encoding returns as object, e.g. Unicode codecs will
672 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
673 will return u"äöü"). This enables codec writer to create codecs
674 for various simple to use conversions.
675
676 New codecs were added to demonstrate these new features (the .encode()
677 and .decode() columns indicate the type of the returned objects):
678
679 Name | .encode() | .decode() | Description
680 ----------------------------------------------------------------------
681 uu | string | string | UU codec (e.g. for email)
682 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000683 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000684 zlib | string | string | zlib compression
685 hex | string | string | 2-byte hex codec
686 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
687
Mark Hammond2a0af792001-05-14 03:09:36 +0000688- Some operating systems now support the concept of a default Unicode
689 encoding for file system operations. Notably, Windows supports 'mbcs'
690 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000691 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000692 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000693
694 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000695 functions that return filenames (such as os.listdir()) to return Python
696 string objects pre-encoded using the default file system encoding for
697 the platform. As this encoding is likely to be different from Python's
698 default encoding, converting this name to a Unicode object before passing
699 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000700 would attempt to use its default encoding (generally ASCII) rather than
701 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000702
Tim Petersa814db52001-05-14 07:05:58 +0000703 In general, this change simply removes surprises when working with
704 Unicode and the file system, making these operations work as you expect,
705 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000706 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000707
Tim Peters61dff2b2001-05-08 15:43:37 +0000708- Float (and complex) literals in source code were evaluated to full
709 precision only when running from a .py file; the same code loaded from a
710 .pyc (or .pyo) file could suffer numeric differences starting at about the
711 12th significant decimal digit. For example, on a machine with IEEE-754
712 floating arithmetic,
713
714 x = 9007199254740992.0
715 print long(x)
716
717 printed 9007199254740992 if run directly from .py, but 9007199254740000
718 if from a compiled (.pyc or .pyo) file. This was due to marshal using
719 str(float) instead of repr(float) when building code objects. marshal
720 now uses repr(float) instead, which should reproduce floats to full
721 machine precision (assuming the platform C float<->string I/O conversion
722 functions are of good quality).
723
724 This may cause floating-point results to change in some cases, and
725 usually for the better, but may also cause numerically unstable
726 algorithms to break.
727
Tim Peters2f228e72001-05-13 00:19:31 +0000728- The implementation of dicts suffers fewer collisions, which has speed
729 benefits. However, the order in which dict entries appear in dict.keys(),
730 dict.values() and dict.items() may differ from previous releases for a
731 given dict. Nothing is defined about this order, so no program should
732 rely on it. Nevertheless, it's easy to write test cases that rely on the
733 order by accident, typically because of printing the str() or repr() of a
734 dict to an "expected results" file. See Lib/test/test_support.py's new
735 sortdict(dict) function for a simple way to display a dict in sorted
736 order.
737
Tim Peters7a3bfc32001-06-12 01:22:22 +0000738- Many other small changes to dicts were made, resulting in faster
739 operation along the most common code paths.
740
Guido van Rossum10315822001-05-01 20:54:30 +0000741- Dictionary objects now support the "in" operator: "x in dict" means
742 the same as dict.has_key(x).
743
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000744- The update() method of dictionaries now accepts generic mapping
745 objects. Specifically the argument object must support the .keys()
746 and __getitem__() methods. This allows you to say, for example,
747 {}.update(UserDict())
748
Guido van Rossum10315822001-05-01 20:54:30 +0000749- Iterators were added; this is a generalized way of providing values
750 to a for loop. See PEP 234. There's a new built-in function iter()
751 to return an iterator. There's a new protocol to get the next value
752 from an iterator using the next() method (in Python) or the
753 tp_iternext slot (in C). There's a new protocol to get iterators
754 using the __iter__() method (in Python) or the tp_iter slot (in C).
755 Iterating (i.e. a for loop) over a dictionary generates its keys.
756 Iterating over a file generates its lines.
757
Tim Petersf553f892001-05-01 20:45:31 +0000758- The following functions were generalized to work nicely with iterator
759 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000760 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000761 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
762 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000763 join() method of strings
764 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000765 'x in y' and 'x not in y' (PySequence_Contains() in C API)
766 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000767 right-hand side of assignment statements with multiple targets, such as
768 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000769
Tim Petersd85e1022001-05-11 21:51:48 +0000770- Accessing module attributes is significantly faster (for example,
771 random.random or os.path or yourPythonModule.yourAttribute).
772
Tim Peterse63415e2001-05-08 04:38:29 +0000773- Comparing dictionary objects via == and != is faster, and now works even
774 if the keys and values don't support comparisons other than ==.
775
Tim Peters95bf9392001-05-10 08:32:44 +0000776- Comparing dictionaries in ways other than == and != is slower: there were
777 insecurities in the dict comparison implementation that could cause Python
778 to crash if the element comparison routines for the dict keys and/or
779 values mutated the dicts. Making the code bulletproof slowed it down.
780
Tim Peterseb28ef22001-06-02 05:27:19 +0000781- Collisions in dicts are resolved via a new approach, which can help
782 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000783 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000784 faster now. Thanks to Christian Tismer for pointing out the cause and
785 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000786
Tim Peters52e155e2001-06-16 05:42:57 +0000787- repr() is much faster for large containers (dict, list, tuple).
788
789
Tim Petersa814db52001-05-14 07:05:58 +0000790Library
791
Fred Drake960fdf92001-07-20 18:38:26 +0000792- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
793 were added to the string module. These a locale-indenpendent
794 constants, unlike letters, lowercase, and uppercase. These are now
795 use in appropriate locations in the standard library.
796
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000797- The flags used in dlopen calls can now be configured using
798 sys.setdlopenflags and queried using sys.getdlopenflags.
799
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000800- Fredrik Lundh's xmlrpclib is now a standard library module. This
801 provides full client-side XML-RPC support. In addition,
802 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
803 one asyncore-based). Thanks to Eric Raymond for the documentation.
804
Guido van Rossum643d3912001-07-05 14:46:25 +0000805- The xrange() object is simplified: it no longer supports slicing,
806 repetition, comparisons, efficient 'in' checking, the tolist()
807 method, or the start, stop and step attributes. See PEP 260.
808
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000809- A new function fnmatch.filter to filter lists of file names was added.
810
Barry Warsawffd674d2001-05-22 16:00:10 +0000811- calendar.py uses month and day names based on the current locale.
812
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000813- strop is now *really* obsolete (this was announced before with 1.6),
814 and issues DeprecationWarning when used (except for the four items
815 that are still imported into string.py).
816
Tim Petersa814db52001-05-14 07:05:58 +0000817- Cookie.py now sorts key+value pairs by key in output strings.
818
819- pprint.isrecursive(object) didn't correctly identify recursive objects.
820 Now it does.
821
Tim Peters95b3f782001-05-14 18:39:41 +0000822- pprint functions now much faster for large containers (tuple, list, dict).
823
Tim Peters7b9542a2001-06-10 23:40:19 +0000824- New 'q' and 'Q' format codes in the struct module, corresponding to C
825 types "long long" and "unsigned long long" (on Windows, __int64). In
826 native mode, these can be used only when the platform C compiler supports
827 these types (when HAVE_LONG_LONG is #define'd by the Python config
828 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000829 In standard mode, 'q' and 'Q' are supported on all platforms, and are
830 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000831
Guido van Rossum83213cc2001-06-12 16:48:52 +0000832- The site module installs a new built-in function 'help' that invokes
833 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
834 it displays a message reminding the user to use 'help()' or
835 'help(object)'.
836
Tim Petersa814db52001-05-14 07:05:58 +0000837Tests
838
839- New test_mutants.py runs dict comparisons where the key and value
840 comparison operators mutute the dicts randomly during comparison. This
841 rapidly causes Python to crash under earlier releases (not for the faint
842 of heart: it can also cause Win9x to freeze or reboot!).
843
844- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000845 pprint.isreadable() return sensible results. Also verifies that simple
846 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000847
Tim Peters4324aa32001-05-28 22:30:08 +0000848C API
849
850- Removed the unused last_is_sticky argument from the internal
851 _PyTuple_Resize(). If this affects you, you were cheating.
852
853
Guido van Rossum55a78992001-07-17 17:22:32 +0000854======================================================================
855
856
Guido van Rossumffe13be2001-04-16 18:46:45 +0000857What's New in Python 2.1 (final)?
858=================================
859
860We only changed a few things since the last release candidate, all in
861Python library code:
862
863- A bug in the locale module was fixed that affected locales which
864 define no grouping for numeric formatting.
865
866- A few bugs in the weakref module's implementations of weak
867 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
868 and the test suite was updated to check for these bugs.
869
870- An old bug in the os.path.walk() function (introduced in Python
871 2.0!) was fixed: a non-existent file would cause an exception
872 instead of being ignored.
873
874- Fixed a few bugs in the new symtable module found by Neil Norwitz's
875 PyChecker.
876
877
Guido van Rossum5b08f132001-04-16 02:05:23 +0000878What's New in Python 2.1c2?
879===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000880
Guido van Rossum5b08f132001-04-16 02:05:23 +0000881A flurry of small changes, and one showstopper fixed in the nick of
882time made it necessary to release another release candidate. The list
883here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000884
Guido van Rossum5b08f132001-04-16 02:05:23 +0000885Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000886
Guido van Rossum5b08f132001-04-16 02:05:23 +0000887- Tim discovered a nasty bug in the dictionary code, caused by
888 PyDict_Next() calling dict_resize(), and the GC code's use of
889 PyDict_Next() violating an assumption in dict_items(). This was
890 fixed with considerable amounts of band-aid, but the net effect is a
891 saner and more robust implementation.
892
893- Made a bunch of symbols static that were accidentally global.
894
895Build and Ports
896
897- The setup.py script didn't check for a new enough version of zlib
898 (1.1.3 is needed). Now it does.
899
900- Changed "make clean" target to also remove shared libraries.
901
902- Added a more general warning about the SGI Irix optimizer to README.
903
904Library
905
906- Fix a bug in urllib.basejoin("http://host", "../file.html") which
907 omitted the slash between host and file.html.
908
909- The mailbox module's _Mailbox class contained a completely broken
910 and undocumented seek() method. Ripped it out.
911
912- Fixed a bunch of typos in various library modules (urllib2, smtpd,
913 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
914
915- Fixed a few last-minute bugs in unittest.
916
917Extensions
918
919- Reverted the patch to the OpenSSL code in socketmodule.c to support
920 RAND_status() and the EGD, and the subsequent patch that tried to
921 fix it for pre-0.9.5 versions; the problem with the patch is that on
922 some systems it issues a warning whenever socket is imported, and
923 that's unacceptable.
924
925Tests
926
927- Fixed the pickle tests to work with "import test.test_pickle".
928
929- Tweaked test_locale.py to actually run the test Windows.
930
931- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
932 not "wb" (which is not a valid mode at all).
933
934- Fix pstats browser crashes. Import readline if it exists to make
935 the user interface nicer.
936
937- Add "import thread" to the top of test modules that import the
938 threading module (test_asynchat and test_threadedtempfile). This
939 prevents test failures caused by a broken threading module resulting
940 from a previously caught failed import.
941
942- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
943 needed on some platforms (e.g. Solaris 8) when the tests are run
944 twice in succession.
945
946- Skip rather than fail test_sunaudiodev if no audio device is found.
947
948
949What's New in Python 2.1c1?
950===========================
951
952This list was significantly updated when 2.1c2 was released; the 2.1c1
953release didn't mention most changes that were actually part of 2.1c1:
954
955Legal
956
957- Copyright was assigned to the Python Software Foundation (PSF) and a
958 PSF license (very similar to the CNRI license) was added.
959
960- The CNRI copyright notice was updated to include 2001.
961
962Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000963
Guido van Rossumc9932722001-04-12 02:31:27 +0000964- After a public outcry, assignment to __debug__ is no longer illegal;
965 instead, a warning is issued. It will become illegal in 2.2.
966
Guido van Rossum5b08f132001-04-16 02:05:23 +0000967- Fixed a core dump with "%#x" % 0, and changed the semantics so that
968 "%#x" now always prepends "0x", even if the value is zero.
969
970- Fixed some nits in the bytecode compiler.
971
972- Fixed core dumps when calling certain kinds of non-functions.
973
974- Fixed various core dumps caused by reference count bugs.
975
976Build and Ports
977
978- Use INSTALL_SCRIPT to install script files.
979
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000980- New port: SCO Unixware 7, by Billy G. Allie.
981
Guido van Rossum5b08f132001-04-16 02:05:23 +0000982- Updated RISCOS port.
983
984- Updated BeOS port and notes.
985
986- Various other porting problems resolved.
987
988Library
989
990- The TERMIOS and SOCKET modules are now truly obsolete and
991 unnecessary. Their symbols are incorporated in the termios and
992 socket modules.
993
994- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
995 better tests for pickling.
996
997- threading: make Condition.wait() robust against KeyboardInterrupt.
998
999- zipfile: add support to zipfile to support opening an archive
1000 represented by an open file rather than a file name. Fix bug where
1001 the archive was not properly closed. Fixed a bug in this bugfix
1002 where flush() was called for a read-only file.
1003
1004- imputil: added an uninstall() method to the ImportManager.
1005
1006- Canvas: fixed bugs in lower() and tkraise() methods.
1007
1008- SocketServer: API change (added overridable close_request() method)
1009 so that the TCP server can explicitly close the request.
1010
1011- pstats: Eric Raymond added a simple interactive statistics browser,
1012 invoked when the module is run as a script.
1013
1014- locale: fixed a problem in format().
1015
1016- webbrowser: made it work when the BROWSER environment variable has a
1017 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
1018 KDE 2. Fixed some other nits.
1019
1020- unittest: changes to allow using a different exception than
1021 AssertionError, and added a few more function aliases. Some other
1022 small changes.
1023
1024- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1025
1026- asynchat: fixed a critical bug in asynchat that slipped through the
1027 2.1b2 release. Fixed another rare bug.
1028
1029- Fix some unqualified except: clauses (always a bad code example).
1030
1031XML
1032
1033- pyexpat: new API get_version_string().
1034
1035- Fixed some minidom bugs.
1036
1037Extensions
1038
1039- Fixed a core dump in _weakref. Removed the weakref.mapping()
1040 function (it adds nothing to the API).
1041
1042- Rationalized the use of header files in the readline module, to make
1043 it compile (albeit with some warnings) with the very recent readline
1044 4.2, without breaking for earlier versions.
1045
1046- Hopefully fixed a buffering problem in linuxaudiodev.
1047
1048- Attempted a fix to make the OpenSSL support in the socket module
1049 work again with pre-0.9.5 versions of OpenSSL.
1050
1051Tests
1052
1053- Added a test case for asynchat and asyncore.
1054
1055- Removed coupling between tests where one test failing could break
1056 another.
1057
1058Tools
1059
1060- Ping added an interactive help browser to pydoc, fixed some nits
1061 in the rest of the pydoc code, and added some features to his
1062 inspect module.
1063
1064- An updated python-mode.el version 4.1 which integrates Ken
1065 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1066 much nicer in XEmacs and Emacs. When stepping through your program
1067 with pdb, in either the shell window or the *Python* window, the
1068 source file and line will be tracked by an arrow. Very cool!
1069
1070- IDLE: syntax warnings in interactive mode are changed into errors.
1071
1072- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001073 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001074
1075- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001076
Barry Warsaw11e89c72001-04-11 20:37:57 +00001077
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001078What's New in Python 2.1 beta 2?
1079================================
1080
Guido van Rossum053ae352001-03-22 14:17:21 +00001081(Unlisted are many fixed bugs, more documentation, etc.)
1082
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001083Core language, builtins, and interpreter
1084
Guido van Rossum053ae352001-03-22 14:17:21 +00001085- The nested scopes work (enabled by "from __future__ import
1086 nested_scopes") is completed; in particular, the future now extends
1087 into code executed through exec, eval() and execfile(), and into the
1088 interactive interpreter.
1089
1090- When calling a base class method (e.g. BaseClass.__init__(self)),
1091 this is now allowed even if self is not strictly spoken a class
1092 instance (e.g. when using metaclasses or the Don Beaudry hook).
1093
1094- Slice objects are now comparable but not hashable; this prevents
1095 dict[:] from being accepted but meaningless.
1096
1097- Complex division is now calculated using less braindead algorithms.
1098 This doesn't change semantics except it's more likely to give useful
1099 results in extreme cases. Complex repr() now uses full precision
1100 like float repr().
1101
1102- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1103
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001104- It is illegal to assign to the name __debug__, which is set when the
1105 interpreter starts. It is effectively a compile-time constant.
1106
1107- A warning will be issued if a global statement for a variable
1108 follows a use or assignment of that variable.
1109
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001110Standard library
1111
Guido van Rossum053ae352001-03-22 14:17:21 +00001112- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1113 inspired by JUnit), is now part of the standard library. You now
1114 have a choice of two testing frameworks: unittest requires you to
1115 write testcases as separate code, doctest gathers them from
1116 docstrings. Both approaches have their advantages and
1117 disadvantages.
1118
1119- A new module Tix was added, which wraps the Tix extension library
1120 for Tk. With that module, it is not necessary to statically link
1121 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1122 require" command. See Demo/tix/.
1123
1124- tzparse.py is now obsolete.
1125
1126- In gzip.py, the seek() and tell() methods are removed -- they were
1127 non-functional anyway, and it's better if callers can test for their
1128 existence with hasattr().
1129
1130Python/C API
1131
1132- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1133 that's already in the dictionary during a PyDict_Next() iteration.
1134 This used to fail occasionally when a dictionary resize operation
1135 could be triggered that would rehash all the keys. All other
1136 modifications to the dictionary are still off-limits during a
1137 PyDict_Next() iteration!
1138
1139- New extended APIs related to passing compiler variables around.
1140
1141- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1142 implement isinstance() and issubclass().
1143
1144- Py_BuildValue() now has a "D" conversion to create a Python complex
1145 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001146
Fred Drake4e262a92001-03-22 18:26:47 +00001147- Extensions types which support weak references must now set the
1148 field allocated for the weak reference machinery to NULL themselves;
1149 this is done to avoid the cost of checking each object for having a
1150 weakly referencable type in PyObject_INIT(), since most types are
1151 not weakly referencable.
1152
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001153- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1154 free variables and cell variables to and from the frame's f_locals.
1155
1156- Variants of several functions defined in pythonrun.h have been added
1157 to support the nested_scopes future statement. The variants all end
1158 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1159 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1160 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001161 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001162
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001163Distutils
1164
1165- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1166 into the release tree.
1167
Tim Peters0e57abf2001-05-02 07:39:38 +00001168- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001169 (an uninstaller, more customization of the installer's display)
1170
1171- from Jack Jansen: added Mac-specific code to generate a dialog for
1172 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001173 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001174 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001175
1176- added 'platforms' and 'keywords' to the set of metadata that can be
1177 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001178
1179- applied patches from Jason Tishler to make the compiler class work with
1180 Cygwin.
1181
1182
Tim Peters2fe289a2001-03-01 22:19:38 +00001183What's New in Python 2.1 beta 1?
1184================================
Tim Petersd66595f2001-02-04 03:09:53 +00001185
1186Core language, builtins, and interpreter
1187
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001188- Following an outcry from the community about the amount of code
1189 broken by the nested scopes feature introduced in 2.1a2, we decided
1190 to make this feature optional, and to wait until Python 2.2 (or at
1191 least 6 months) to make it standard. The option can be enabled on a
1192 per-module basis by adding "from __future__ import nested_scopes" at
1193 the beginning of a module (before any other statements, but after
1194 comments and an optional docstring). See PEP 236 (Back to the
1195 __future__) for a description of the __future__ statement. PEP 227
1196 (Statically Nested Scopes) has been updated to reflect this change,
1197 and to clarify the semantics in a number of endcases.
1198
1199- The nested scopes code, when enabled, has been hardened, and most
1200 bugs and memory leaks in it have been fixed.
1201
1202- Compile-time warnings are now generated for a number of conditions
1203 that will break or change in meaning when nested scopes are enabled:
1204
1205 - Using "from...import *" or "exec" without in-clause in a function
1206 scope that also defines a lambda or nested function with one or
1207 more free (non-local) variables. The presence of the import* or
1208 bare exec makes it impossible for the compiler to determine the
1209 exact set of local variables in the outer scope, which makes it
1210 impossible to determine the bindings for free variables in the
1211 inner scope. To avoid the warning about import *, change it into
1212 an import of explicitly name object, or move the import* statement
1213 to the global scope; to avoid the warning about bare exec, use
1214 exec...in... (a good idea anyway -- there's a possibility that
1215 bare exec will be deprecated in the future).
1216
1217 - Use of a global variable in a nested scope with the same name as a
1218 local variable in a surrounding scope. This will change in
1219 meaning with nested scopes: the name in the inner scope will
1220 reference the variable in the outer scope rather than the global
1221 of the same name. To avoid the warning, either rename the outer
1222 variable, or use a global statement in the inner function.
1223
Neil Schemenauera35c6882001-02-27 04:45:05 +00001224- An optional object allocator has been included. This allocator is
1225 optimized for Python objects and should be faster and use less memory
1226 than the standard system allocator. It is not enabled by default
1227 because of possible thread safety problems. The allocator is only
1228 protected by the Python interpreter lock and it is possible that some
1229 extension modules require a thread safe allocator. The object
1230 allocator can be enabled by providing the "--with-pymalloc" option to
1231 configure.
1232
Tim Petersd66595f2001-02-04 03:09:53 +00001233Standard library
1234
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001235- pyexpat now detects the expat version if expat.h defines it. A
1236 number of additional handlers are provided, which are only available
1237 since expat 1.95. In addition, the methods SetParamEntityParsing and
1238 GetInputContext of Parser objects are available with 1.95.x
1239 only. Parser objects now provide the ordered_attributes and
1240 specified_attributes attributes. A new module expat.model was added,
1241 which offers a number of additional constants if 1.95.x is used.
1242
1243- xml.dom offers the new functions registerDOMImplementation and
1244 getDOMImplementation.
1245
1246- xml.dom.minidom offers a toprettyxml method. A number of DOM
1247 conformance issues have been resolved. In particular, Element now
1248 has an hasAttributes method, and the handling of namespaces was
1249 improved.
1250
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001251- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1252 getting information about live Python code, and pydoc.py, a module
1253 for interactively converting docstrings to HTML or text.
1254 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001255 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001256 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1257 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001258
Tim Peters1eff7962001-03-01 02:31:33 +00001259- New library module difflib.py, primarily packaging the SequenceMatcher
1260 class at the heart of the popular ndiff.py file-comparison tool.
1261
1262- doctest.py (a framework for verifying Python code examples in docstrings)
1263 is now part of the std library.
1264
Tim Petersd66595f2001-02-04 03:09:53 +00001265Windows changes
1266
Guido van Rossume3955a82001-03-02 14:05:59 +00001267- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1268 small GUI that lets you browse the module docstrings using your
1269 default web browser.
1270
Tim Peters1eff7962001-03-01 02:31:33 +00001271- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1272 Platforms) is implemented. See
1273
1274 http://python.sourceforge.net/peps/pep-0235.html
1275
1276 for full details, especially the "Current Lower-Left Semantics" section.
1277 The new Windows import rules are simpler than before:
1278
1279 A. If the PYTHONCASEOK environment variable exists, same as
1280 before: silently accept the first case-insensitive match of any
1281 kind; raise ImportError if none found.
1282
1283 B. Else search sys.path for the first case-sensitive match; raise
1284 ImportError if none found.
1285
1286 The same rules have been implented on other platforms with case-
1287 insensitive but case-preserving filesystems too (including Cygwin, and
1288 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001289
Tim Peters25a9ce32001-02-19 07:06:36 +00001290- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1291 what it's supposed to do (and does do under NT and 2000) via direct
1292 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001293 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001294 all Win9x systems before.
1295
Tim Peters1eff7962001-03-01 02:31:33 +00001296- Build: Subproject _test (effectively) renamed to _testcapi.
1297
Tim Peters2fe289a2001-03-01 22:19:38 +00001298New platforms
1299
1300- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1301 Thanks to Steven Majewski!
1302
1303- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1304 Tishler!
1305
Guido van Rossum9089b272001-03-02 06:49:50 +00001306- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1307 Schwertberger! See RISCOS/README for more information -- it seems
1308 that because of the bizarre filename conventions on RISCOS, no port
1309 to that platform is easy. Note that the new variable os.endsep is
1310 silently supported in order to make life easier on this platform,
1311 but we don't advertise it because it's not worth for most folks to
1312 care about RISCOS portability.
1313
Tim Peters25a9ce32001-02-19 07:06:36 +00001314
Tim Petersd7b5e882001-01-25 03:36:26 +00001315What's New in Python 2.1 alpha 2?
1316=================================
Tim Peters40ead762001-01-27 05:35:26 +00001317
Tim Petersd7b5e882001-01-25 03:36:26 +00001318Core language, builtins, and interpreter
1319
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001320- Scopes nest. If a name is used in a function or class, but is not
1321 local, the definition in the nearest enclosing function scope will
1322 be used. One consequence of this change is that lambda statements
1323 could reference variables in the namespaces where the lambda is
1324 defined. In some unusual cases, this change will break code.
1325
1326 In all previous version of Python, names were resolved in exactly
1327 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001328 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001329 function A is defined within a function B, the names bound in B are
1330 not visible in A. The new rules make names bound in B visible in A,
1331 unless A contains a name binding that hides the binding in B.
1332
1333 Section 4.1 of the reference manual describes the new scoping rules
1334 in detail. The test script in Lib/test/test_scope.py demonstrates
1335 some of the effects of the change.
1336
1337 The new rules will cause existing code to break if it defines nested
1338 functions where an outer function has local variables with the same
1339 name as globals or builtins used by the inner function. Example:
1340
1341 def munge(str):
1342 def helper(x):
1343 return str(x)
1344 if type(str) != type(''):
1345 str = helper(str)
1346 return str.strip()
1347
1348 Under the old rules, the name str in helper() is bound to the
1349 builtin function str(). Under the new rules, it will be bound to
1350 the argument named str and an error will occur when helper() is
1351 called.
1352
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001353- The compiler will report a SyntaxError if "from ... import *" occurs
1354 in a function or class scope. The language reference has documented
1355 that this case is illegal, but the compiler never checked for it.
1356 The recent introduction of nested scope makes the meaning of this
1357 form of name binding ambiguous. In a future release, the compiler
1358 may allow this form when there is no possibility of ambiguity.
1359
Tim Peters40ead762001-01-27 05:35:26 +00001360- repr(string) is easier to read, now using hex escapes instead of octal,
1361 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1362
1363 >>> "\texample \r\n" + chr(0) + chr(255)
1364 '\texample \r\n\x00\xff' # in 2.1
1365 '\011example \015\012\000\377' # in 2.0
1366
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001367- Functions are now compared and hashed by identity, not by value, since
1368 the func_code attribute is writable.
1369
Fred Drakefb9d7122001-02-01 20:00:40 +00001370- Weak references (PEP 205) have been added. This involves a few
1371 changes in the core, an extension module (_weakref), and a Python
1372 module (weakref). The weakref module is the public interface. It
1373 includes support for "explicit" weak references, proxy objects, and
1374 mappings with weakly held values.
1375
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001376- A 'continue' statement can now appear in a try block within the body
1377 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001378 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001379
Tim Petersd7b5e882001-01-25 03:36:26 +00001380Standard library
1381
Barry Warsaw30dbd142001-01-31 22:14:01 +00001382- mailbox.py now has a new class, PortableUnixMailbox which is
1383 identical to UnixMailbox but uses a more portable scheme for
1384 determining From_ separators. Also, the constructors for all the
1385 classes in this module have a new optional `factory' argument, which
1386 is a callable used when new message classes must be instantiated by
1387 the next() method.
1388
Tim Petersd7b5e882001-01-25 03:36:26 +00001389- random.py is now self-contained, and offers all the functionality of
1390 the now-deprecated whrandom.py. See the docs for details. random.py
1391 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001392 and restoring the internal state of the generator; and jumpahead(n),
1393 for quickly forcing the internal state to be the same as if n calls to
1394 random() had been made. The latter is particularly useful for multi-
1395 threaded programs, creating one instance of the random.Random() class for
1396 each thread, then using .jumpahead() to force each instance to use a
1397 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001398
Tim Peters0de88fc2001-02-01 04:59:18 +00001399- random.py's seed() function is new. For bit-for-bit compatibility with
1400 prior releases, use the whseed function instead. The new seed function
1401 addresses two problems: (1) The old function couldn't produce more than
1402 about 2**24 distinct internal states; the new one about 2**45 (the best
1403 that can be done in the Wichmann-Hill generator). (2) The old function
1404 sometimes produced identical internal states when passed distinct
1405 integers, and there was no simple way to predict when that would happen;
1406 the new one guarantees to produce distinct internal states for all
1407 arguments in [0, 27814431486576L).
1408
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001409- The socket module now supports raw packets on Linux. The socket
1410 family is AF_PACKET.
1411
Tim Peters9ea17ac2001-02-02 05:57:15 +00001412- test_capi.py is a start at running tests of the Python C API. The tests
1413 are implemented by the new Modules/_testmodule.c.
1414
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001415- A new extension module, _symtable, provides provisional access to the
1416 internal symbol table used by the Python compiler. A higher-level
1417 interface will be added on top of _symtable in a future release.
1418
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001419- Removed the obsolete soundex module.
1420
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001421- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1422 the isSameNode method; NamedNodeMap the get method.
1423
1424- xml.sax.expatreader supports the lexical handler property; it
1425 generates comment, startCDATA, and endCDATA events.
1426
Tim Petersee826f82001-01-31 19:39:44 +00001427Windows changes
1428
1429- Build procedure: the zlib project is built in a different way that
1430 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001431 the zlib binary used. See PCbuild\readme.txt for details. Your old
1432 zlib-related directories can be deleted; you'll need to download fresh
1433 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001434
Tim Peters9ea17ac2001-02-02 05:57:15 +00001435- Build: New subproject _test for the benefit of test_capi.py (see above).
1436
Tim Petersb16c56f2001-02-02 21:24:51 +00001437- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1438 interface to some Python compiler internals).
1439
1440- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001441 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001442
Tim Petersa3a3a032000-11-30 05:22:44 +00001443What's New in Python 2.1 alpha 1?
1444=================================
1445
1446Core language, builtins, and interpreter
1447
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001448- There is a new Unicode companion to the PyObject_Str() API
1449 called PyObject_Unicode(). It behaves in the same way as the
1450 former, but assures that the returned value is an Unicode object
1451 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001452
Guido van Rossumf98eda02001-01-17 15:54:45 +00001453- The comparison operators support "rich comparison overloading" (PEP
1454 207). C extension types can provide a rich comparison function in
1455 the new tp_richcompare slot in the type object. The cmp() function
1456 and the C function PyObject_Compare() first try the new rich
1457 comparison operators before trying the old 3-way comparison. There
1458 is also a new C API PyObject_RichCompare() (which also falls back on
1459 the old 3-way comparison, but does not constrain the outcome of the
1460 rich comparison to a Boolean result).
1461
1462 The rich comparison function takes two objects (at least one of
1463 which is guaranteed to have the type that provided the function) and
1464 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1465 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1466 object, which may be NotImplemented (in which case the tp_compare
1467 slot function is used as a fallback, if defined).
1468
1469 Classes can overload individual comparison operators by defining one
1470 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001471 __ge__. There are no explicit "reflected argument" versions of
1472 these; instead, __lt__ and __gt__ are each other's reflection,
1473 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1474 reflection (similar at the C level). No other implications are
1475 made; in particular, Python does not assume that == is the Boolean
1476 inverse of !=, or that < is the Boolean inverse of >=. This makes
1477 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001478
1479 Classes or types that want to implement (in)equality tests but not
1480 the ordering operators (i.e. unordered types) should implement ==
1481 and !=, and raise an error for the ordering operators.
1482
Guido van Rossuma88479f2001-01-18 14:28:08 +00001483 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001484 Boolean; e.g. a matrix type might want to return a matrix of bits
1485 for A < B, giving elementwise comparisons. Such types should ensure
1486 that any interpretation of their value in a Boolean context raises
1487 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1488 at the C level) to always raise an exception.
1489
Guido van Rossuma88479f2001-01-18 14:28:08 +00001490- Complex numbers use rich comparisons to define == and != but raise
1491 an exception for <, <=, > and >=. Unfortunately, this also means
1492 that cmp() of two complex numbers raises an exception when the two
1493 numbers differ. Since it is not mathematically meaningful to compare
1494 complex numbers except for equality, I hope that this doesn't break
1495 too much code.
1496
Tim Peters3389f192001-02-18 08:48:49 +00001497- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001498 not defined by the language, other than that it's arbitrary but
1499 consistent (see the Reference Manual). An implementation detail changed
1500 in 2.1a1 such that None now compares less than any other object. Code
1501 relying on this new behavior (like code that relied on the previous
1502 behavior) does so at its own risk.
1503
Barry Warsaw573b5412001-01-15 20:43:18 +00001504- Functions and methods now support getting and setting arbitrarily
1505 named attributes (PEP 232). Functions have a new __dict__
1506 (a.k.a. func_dict) which hold the function attributes. Methods get
1507 and set attributes on their underlying im_func. It is a TypeError
1508 to set an attribute on a bound method.
1509
Guido van Rossum051e3352001-01-15 19:11:10 +00001510- The xrange() object implementation has been improved so that
1511 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1512 limitation that in this case len(xrange(sys.maxint)) can't be
1513 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1514 work fine as long as the index i doesn't actually reach 2**31.
1515 (Python uses regular ints for sequence and string indices; fixing
1516 that is much more work.)
1517
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001518- Two changes to from...import:
1519
Guido van Rossumba381232001-02-03 15:06:40 +00001520 1) "from M import X" now works even if (after loading module M)
1521 sys.modules['M'] is not a real module; it's basically a getattr()
1522 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001523
1524 2) "from M import *" now looks for M.__all__ to decide which names to
1525 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1526 filters out names starting with '_' as before. Whether or not
1527 __all__ exists, there's no restriction on the type of M.
1528
Guido van Rossumf61f1662001-01-10 20:13:55 +00001529- File objects have a new method, xreadlines(). This is the fastest
1530 way to iterate over all lines in a file:
1531
1532 for line in file.xreadlines():
1533 ...do something to line...
1534
1535 See the xreadlines module (mentioned below) for how to do this for
1536 other file-like objects.
1537
1538- Even if you don't use file.xreadlines(), you may expect a speedup on
1539 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001540 quite a bit in platform-specific ways: on systems (like Linux) that
1541 support flockfile(), getc_unlocked(), and funlockfile(), those are
1542 used by default. On systems (like Windows) without getc_unlocked(),
1543 a complicated (but still thread-safe) method using fgets() is used by
1544 default.
1545
Tim Petersd52269b2001-01-25 06:23:18 +00001546 You can force use of the fgets() method by #define'ing
1547 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001548 getc_unlocked()).
1549
Tim Petersd52269b2001-01-25 06:23:18 +00001550 You can force fgets() not to be used by #define'ing
1551 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001552 test_bufio.py fails -- and let us know if it does!).
1553
1554- In addition, the fileinput module, while still slower than the other
1555 methods on most platforms, has been sped up too, by using
1556 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001557
1558- Support for run-time warnings has been added, including a new
1559 command line option (-W) to specify the disposition of warnings.
1560 See the description of the warnings module below.
1561
1562- Extensive changes have been made to the coercion code. This mostly
1563 affects extension modules (which can now implement mixed-type
1564 numerical operators without having to use coercion), but
1565 occasionally, in boundary cases the coercion semantics have changed
1566 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001567 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001568 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001569 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001570
Guido van Rossumf98eda02001-01-17 15:54:45 +00001571- In connection with the coercion changes, a new built-in singleton
1572 object, NotImplemented is defined. This can be returned for
1573 operations that wish to indicate they are not implemented for a
1574 particular combination of arguments. From C, this is
1575 Py_NotImplemented.
1576
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001577- The interpreter accepts now bytecode files on the command line even
1578 if they do not have a .pyc or .pyo extension. On Linux, after executing
1579
Martin v. Löwise214baa2001-02-04 22:37:56 +00001580import imp,sys,string
1581magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1582reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1583open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001584
1585 any byte code file can be used as an executable (i.e. as an argument
1586 to execve(2)).
1587
Tim Peters9940b802000-12-01 07:59:35 +00001588- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001589 character. In 1.6 and earlier, they never produced a sign,
1590 and raised an error if the value of the long was too large
1591 to fit in a Python int. In 2.0, they produced a sign if and
1592 only if too large to fit in an int. This was inconsistent
1593 across platforms (because the size of an int varies across
1594 platforms), and inconsistent with hex() and oct(). Example:
1595
1596 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001597 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001598 'ffffffbe' # in 2.0 and before, on 32-bit machines
1599 >>> hex(-0x42L)
1600 '-0x42L' # in all versions of Python
1601
Tim Peters9940b802000-12-01 07:59:35 +00001602 The behavior of %d formats for negative Python longs remains
1603 the same as in 2.0 (although in 1.6 and before, they raised
1604 an error if the long didn't fit in a Python int).
1605
1606 %u formats don't make sense for Python longs, but are allowed
1607 and treated the same as %d in 2.1. In 2.0, a negative long
1608 formatted via %u produced a sign if and only if too large to
1609 fit in an int. In 1.6 and earlier, a negative long formatted
1610 via %u raised an error if it was too big to fit in an int.
1611
Guido van Rossum3661d392000-12-12 22:10:31 +00001612- Dictionary objects have an odd new method, popitem(). This removes
1613 an arbitrary item from the dictionary and returns it (in the form of
1614 a (key, value) pair). This can be useful for algorithms that use a
1615 dictionary as a bag of "to do" items and repeatedly need to pick one
1616 item. Such algorithms normally end up running in quadratic time;
1617 using popitem() they can usually be made to run in linear time.
1618
Tim Peters36cdad12000-12-29 02:06:45 +00001619Standard library
1620
Thomas Woutersfe385252001-01-19 23:16:56 +00001621- In the time module, the time argument to the functions strftime,
1622 localtime, gmtime, asctime and ctime is now optional, defaulting to
1623 the current time (in the local timezone).
1624
Guido van Rossumda91f222001-01-15 16:36:08 +00001625- The ftplib module now defaults to passive mode, which is deemed a
1626 more useful default given that clients are often inside firewalls
1627 these days. Note that this could break if ftplib is used to connect
1628 to a *server* that is inside a firewall, from outside; this is
1629 expected to be a very rare situation. To fix that, you can call
1630 ftp.set_pasv(0).
1631
Martin v. Löwis10a27872001-01-13 09:54:41 +00001632- The module site now treats .pth files not only for path configuration,
1633 but also supports extensions to the initialization code: Lines starting
1634 with import are executed.
1635
Guido van Rossumf61f1662001-01-10 20:13:55 +00001636- There's a new module, warnings, which implements a mechanism for
1637 issuing and filtering warnings. There are some new built-in
1638 exceptions that serve as warning categories, and a new command line
1639 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1640 turns warnings into errors). warnings.warn(message[, category])
1641 issues a warning message; this can also be called from C as
1642 PyErr_Warn(category, message).
1643
1644- A new module xreadlines was added. This exports a single factory
1645 function, xreadlines(). The intention is that this code is the
1646 absolutely fastest way to iterate over all lines in an open
1647 file(-like) object:
1648
1649 import xreadlines
1650 for line in xreadlines.xreadlines(file):
1651 ...do something to line...
1652
1653 This is equivalent to the previous the speed record holder using
1654 file.readlines(sizehint). Note that if file is a real file object
1655 (as opposed to a file-like object), this is equivalent:
1656
1657 for line in file.xreadlines():
1658 ...do something to line...
1659
Tim Peters36cdad12000-12-29 02:06:45 +00001660- The bisect module has new functions bisect_left, insort_left,
1661 bisect_right and insort_right. The old names bisect and insort
1662 are now aliases for bisect_right and insort_right. XXX_right
1663 and XXX_left methods differ in what happens when the new element
1664 compares equal to one or more elements already in the list: the
1665 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001666 right. Code that doesn't care where equal elements end up should
1667 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001668
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001669- The new curses.panel module wraps the panel library that forms part
1670 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1671
Guido van Rossumf61f1662001-01-10 20:13:55 +00001672- The SocketServer module now sets the allow_reuse_address flag by
1673 default in the TCPServer class.
1674
1675- A new function, sys._getframe(), returns the stack frame pointer of
1676 the caller. This is intended only as a building block for
1677 higher-level mechanisms such as string interpolation.
1678
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001679- The pyexpat module supports a number of new handlers, which are
1680 available only in expat 1.2. If invocation of a callback fails, it
1681 will report an additional frame in the traceback. Parser objects
1682 participate now in garbage collection. If expat reports an unknown
1683 encoding, pyexpat will try to use a Python codec; that works only
1684 for single-byte charsets. The parser type objects is exposed as
1685 XMLParserObject.
1686
1687- xml.dom now offers standard definitions for symbolic node type and
1688 exception code constants, and a hierarchy of DOM exceptions. minidom
1689 was adjusted to use them.
1690
1691- The conformance of xml.dom.minidom to the DOM specification was
1692 improved. It detects a number of additional error cases; the
1693 previous/next relationship works even when the tree is modified;
1694 Node supports the normalize() method; NamedNodeMap, DocumentType and
1695 DOMImplementation classes were added; Element supports the
1696 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1697 method.
1698
Guido van Rossumf61f1662001-01-10 20:13:55 +00001699Build issues
1700
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001701- For Unix (and Unix-compatible) builds, configuration and building of
1702 extension modules is now greatly automated. Rather than having to
1703 edit the Modules/Setup file to indicate which modules should be
1704 built and where their include files and libraries are, a
1705 distutils-based setup.py script now takes care of building most
1706 extension modules. All extension modules built this way are built
1707 as shared libraries. Only a few modules that must be linked
1708 statically are still listed in the Setup file; you won't need to
1709 edit their configuration.
1710
1711- Python should now build out of the box on Cygwin. If it doesn't,
1712 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001713
1714- Python now always uses its own (renamed) implementation of getopt()
1715 -- there's too much variation among C library getopt()
1716 implementations.
1717
1718- C++ compilers are better supported; the CXX macro is always set to a
1719 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001720
Tim Petersd92dfe02000-12-12 01:18:41 +00001721Windows changes
1722
1723- select module: By default under Windows, a select() call
1724 can specify no more than 64 sockets. Python now boosts
1725 this Microsoft default to 512. If you need even more than
1726 that, see the MS docs (you'll need to #define FD_SETSIZE
1727 and recompile Python from source).
1728
Guido van Rossumf61f1662001-01-10 20:13:55 +00001729- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1730 subdirectory is no more!
1731
Tim Petersa3a3a032000-11-30 05:22:44 +00001732
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001733What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001734=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001735
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001736Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001737changes are in the file HISTORY. If you are making the jump directly
1738from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1739HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001740
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001741Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1742the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1743http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001744
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001745--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001746
1747======================================================================
1748
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001749What's new in 2.0 (since release candidate 1)?
1750==============================================
1751
1752Standard library
1753
1754- The copy_reg module was modified to clarify its intended use: to
1755 register pickle support for extension types, not for classes.
1756 pickle() will raise a TypeError if it is passed a class.
1757
1758- Fixed a bug in gettext's "normalize and expand" code that prevented
1759 it from finding an existing .mo file.
1760
1761- Restored support for HTTP/0.9 servers in httplib.
1762
Tim Peters989b7b92000-10-16 20:24:53 +00001763- The math module was changed to stop raising OverflowError in case of
1764 underflow, and return 0 instead in underflow cases. Whether Python
1765 used to raise OverflowError in case of underflow was platform-
1766 dependent (it did when the platform math library set errno to ERANGE
1767 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001768
1769- Fixed a bug in StringIO that occurred when the file position was not
1770 at the end of the file and write() was called with enough data to
1771 extend past the end of the file.
1772
1773- Fixed a bug that caused Tkinter error messages to get lost on
1774 Windows. The bug was fixed by replacing direct use of
1775 interp->result with Tcl_GetStringResult(interp).
1776
1777- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1778 redirect response.
1779
1780- Several changes were made to distutils: Some debugging code was
1781 removed from util. Fixed the installer used when an external zip
1782 program (like WinZip) is not found; the source code for this
1783 installer is in Misc/distutils. check_lib() was modified to behave
1784 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1785 test for whether installed modules are on sys.path was changed to
1786 use both normcase() and normpath().
1787
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001788- Several minor bugs were fixed in the xml package (the minidom,
1789 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001790
1791- The regression test driver (regrtest.py) behavior when invoked with
1792 -l changed: It now reports a count of objects that are recognized as
1793 garbage but not freed by the garbage collector.
1794
Tim Peters989b7b92000-10-16 20:24:53 +00001795- The regression test for the math module was changed to test
1796 exceptional behavior when the test is run in verbose mode. Python
1797 cannot yet guarantee consistent exception behavior across platforms,
1798 so the exception part of test_math is run only in verbose mode, and
1799 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001800
1801Internals
1802
1803- PyOS_CheckStack() has been disabled on Win64, where it caused
1804 test_sre to fail.
1805
1806Build issues
1807
1808- Changed compiler flags, so that gcc is always invoked with -Wall and
1809 -Wstrict-prototypes. Users compiling Python with GCC should see
1810 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001811 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001812 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001813
Tim Petersa3a3a032000-11-30 05:22:44 +00001814- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001815
1816Tools and other miscellany
1817
1818- The compiler in Tools/compiler was updated to support the new
1819 language features introduced in 2.0: extended print statement, list
1820 comprehensions, and augmented assignments. The new compiler should
1821 also be backwards compatible with Python 1.5.2; the compiler will
1822 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001823 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001824
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001825What's new in 2.0 release candidate 1 (since beta 2)?
1826=====================================================
1827
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001828What is release candidate 1?
1829
1830We believe that release candidate 1 will fix all known bugs that we
1831intend to fix for the 2.0 final release. This release should be a bit
1832more stable than the previous betas. We would like to see even more
1833widespread testing before the final release, so we are producing this
1834release candidate. The final release will be exactly the same unless
1835any show-stopping (or brown bag) bugs are found by testers of the
1836release candidate.
1837
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001838All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001839to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001840
1841Core language, builtins, and interpreter
1842
1843- A bug that caused crashes when __coerce__ was used with augmented
1844 assignment, e.g. +=, was fixed.
1845
1846- Raise ZeroDivisionError when raising zero to a negative number,
1847 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1848 power operator and the result of math.pow(0.0, -2.0) will vary by
1849 platform. On Linux, it raises a ValueError.
1850
1851- A bug in Unicode string interpolation was fixed that occasionally
1852 caused errors with formats including "%%". For example, the
1853 following expression "%% %s" % u"abc" no longer raises a TypeError.
1854
1855- Compilation of deeply nested expressions raises MemoryError instead
1856 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1857
1858- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1859 rendering them useless. They are now written in binary mode again.
1860
1861Standard library
1862
1863- Keyword arguments are now accepted for most pattern and match object
1864 methods in SRE, the standard regular expression engine.
1865
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001866- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001867 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001868
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001869- Several bugs in the Unicode handling and error handling in _tkinter
1870 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001871
1872- Fix memory management errors in Merge() and Tkapp_Call() routines.
1873
1874- Several changes were made to cStringIO to make it compatible with
1875 the file-like object interface and with StringIO. If operations are
1876 performed on a closed object, an exception is raised. The truncate
1877 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001878 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001879
1880- There were many changes made to the linuxaudiodev module and its
1881 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001882 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001883
1884 Note that this module is named poorly, because it should work
1885 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001886 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001887
1888 The module now raises exceptions when errors occur instead of
1889 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1890 audio) and defines a getptr() method that calls the
1891 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1892
1893- The library_version attribute, introduced in an earlier beta, was
1894 removed because it can not be supported with early versions of the C
1895 readline library, which provides no way to determine the version at
1896 compile-time.
1897
1898- The binascii module is now enabled on Win64.
1899
Tim Peters46446d62000-10-09 21:19:31 +00001900- tokenize.py no longer suffers "recursion depth" errors when parsing
1901 programs with very long string literals.
1902
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001903Internals
1904
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001905- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001906 which is called when the interpreter starts up to determine where
1907 the standard library is installed. These vulnerabilities affect all
1908 previous versions of Python and can be exploited by setting very
1909 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1910 setuid Python script, although use of the wrapper in
1911 Misc/setuid-prog.c will eliminate the vulnerability.
1912
1913- Fixed garbage collection bugs in instance creation that were
1914 triggered when errors occurred during initialization. The solution,
1915 applied in cPickle and in PyInstance_New(), is to call
1916 PyObject_GC_Init() after the initialization of the object's
1917 container attributes is complete.
1918
1919- pyexpat adds definitions of PyModule_AddStringConstant and
1920 PyModule_AddObject if the Python version is less than 2.0, which
1921 provides compatibility with PyXML on Python 1.5.2.
1922
1923- If the platform has a bogus definition for LONG_BIT (the number of
1924 bits in a long), an error will be reported at compile time.
1925
1926- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1927 collection crashes and possibly other, unreported crashes.
1928
1929- Fixed a memory leak in _PyUnicode_Fini().
1930
1931Build issues
1932
1933- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001934 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001935 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001936
1937- The mmap.PAGESIZE constant is now initialized using sysconf when
1938 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1939
1940- The md5 file should now compile on all platforms.
1941
1942- The select module now compiles on platforms that do not define
1943 POLLRDNORM and related constants.
1944
1945- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001946 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001947
Jeremy Hylton10921202000-10-09 18:34:12 +00001948- BeOS: A number of changes were made to the build and installation
1949 process. ar-fake now operates on a directory of object files.
1950 dl_export.h is gone, and its macros now appear on the mwcc command
1951 line during build on PPC BeOS.
1952
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001953- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001954 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001955
1956- Cygwin: Support for shared libraries, Tkinter, and sockets.
1957
1958- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1959
1960Tools and other miscellany
1961
1962- Removed debugging prints from main used with freeze.
1963
Tim Peters46446d62000-10-09 21:19:31 +00001964- IDLE auto-indent no longer crashes when it encounters Unicode
1965 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001966
1967What's new in 2.0 beta 2 (since beta 1)?
1968========================================
1969
1970Core language, builtins, and interpreter
1971
Tim Peters482c0212000-09-26 06:33:09 +00001972- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001973 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001974
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001975- Add -h and -V command line options to print the usage message and
1976 Python version number and exit immediately.
1977
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001978- eval() and exec accept Unicode objects as code parameters.
1979
1980- getattr() and setattr() now also accept Unicode objects for the
1981 attribute name, which are converted to strings using the default
1982 encoding before lookup.
1983
1984- Multiplication on string and Unicode now does proper bounds
1985 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1986 string is too long."
1987
1988- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001989 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001990
Jeremy Hylton1b618592000-09-26 05:32:36 +00001991
1992Standard library and extensions
1993
Guido van Rossum5b08f132001-04-16 02:05:23 +00001994- socket module: the OpenSSL code now adds support for RAND_status()
1995 and EGD (Entropy Gathering Device).
1996
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001997- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001998 argument checking; it still takes no arguments.
1999
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002000- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002001
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002002- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002003
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002004- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002005
2006- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002007 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002008
2009- copy: Copy Unicode objects atomically.
2010
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002011- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002012
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002013- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002014
Fred Drake67233bc2000-09-26 16:40:27 +00002015- dbm: Add get() and setdefault() methods to dbm object. Add constant
2016 `library' to module that names the library used. Added doc strings
2017 and method names to error messages. Uses configure to determine
2018 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
2019 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002020
2021- distutils: Update to version 0.9.3.
2022
2023- dl: Add several dl.RTLD_ constants.
2024
2025- fpectl: Now supported on FreeBSD.
2026
2027- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2028 found by the collector will be saved in gc.garbage. This is useful
2029 for debugging a program that creates reference cycles.
2030
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002031- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002032 of HTTP class. Do not close socket on zero-length response. Do not
2033 crash when server sends invalid content-length header.
2034
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002035- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002036
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002037- marshal: When reading a short, sign-extend on platforms where shorts
2038 are bigger than 16 bits. When reading a long, repair the unportable
2039 sign extension that was being done for 64-bit machines. (It assumed
2040 that signed right shift sign-extends.)
2041
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002042- operator: Add contains(), invert(), __invert__() as aliases for
2043 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002044
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002045- os: Add support for popen2() and popen3() on all platforms where
2046 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002047
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002048- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002049 clicking on a file in Explorer (or passing the file name to the
2050 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002051
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002052- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002053 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002054
2055- pickle: Now raises ValueError when an invalid pickle that contains
2056 a non-string repr where a string repr was expected. This behavior
2057 matches cPickle.
2058
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002059- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002060
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002061- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002062
2063- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002064 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002065 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002066
2067- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002068 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002069
2070- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002071 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002072 few cycles during startup since the first call to
2073 setdefaultencoding() will initialize the codec registry and the
2074 encodings package.
2075
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002076- socket: Support for size hint in readlines() method of object returned
2077 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002078
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002079- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002080 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002081 is followed by whitespace.
2082
Tim Petersa3a3a032000-11-30 05:22:44 +00002083- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002084
2085- struct: Check ranges for bytes and shorts.
2086
2087- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002088 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002089
2090- Tkinter: Image objects are now guaranteed to have unique ids. Set
2091 event.delta to zero if Tk version doesn't support mousewheel.
2092 Removed some debugging prints.
2093
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002094- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002095
Fred Drake67233bc2000-09-26 16:40:27 +00002096- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002097 which works around a bug in Norton AntiVirus 2000 that leads directly
2098 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002099
2100- xml: New version detection code allows PyXML to override standard
2101 XML package if PyXML version is greater than 0.6.1.
2102
Fred Drake64bb3802000-09-26 16:21:35 +00002103- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2104 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2105 tree only for nodes which are sufficiently interesting to a specific
2106 application. Does not provide the HTML-specific extensions. Still
2107 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002108
Fred Drake64bb3802000-09-26 16:21:35 +00002109- xml.sax: SAX 2 support for Python, including all the handler
2110 interfaces needed to process XML 1.0 compliant XML. Some
2111 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002112
Fred Drake64bb3802000-09-26 16:21:35 +00002113- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2114 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002115
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002116
Jeremy Hylton1b618592000-09-26 05:32:36 +00002117C API
2118
2119- Add three new convenience functions for module initialization --
2120 PyModule_AddObject(), PyModule_AddIntConstant(), and
2121 PyModule_AddStringConstant().
2122
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002123- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002124 removed and add #error to Python.h if NULL isn't defined after
2125 #include of stdio.h.
2126
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002127- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002128 backwards compatibility (at the source level) with old extensions.
2129
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002130- A wrapper API was added for signal() and sigaction(). Instead of
2131 either function, always use PyOS_getsig() to get a signal handler
2132 and PyOS_setsig() to set one. A new convenience typedef
2133 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002134
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002135- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002136 internal data buffer and size of a string object -- or the default
2137 encoded version of a Unicode object.
2138
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002139- PyString_Size() and PyString_AsString() accept Unicode objects.
2140
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002141- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002142 exists). INT_MAX and LONG_MAX will always be defined, even if
2143 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002144
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002145- PyFloat_FromString takes a second argument, pend, that was
2146 effectively useless. It is now officially useless but preserved for
2147 backwards compatibility. If the pend argument is not NULL, *pend is
2148 set to NULL.
2149
2150- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2151 for the attribute name. See note on getattr() above.
2152
2153- A few bug fixes to argument processing for Unicode.
2154 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2155 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2156 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002157 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002158
2159- Py_BuildValue accepts B format (for bgen-generated code).
2160
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002161
Jeremy Hylton1b618592000-09-26 05:32:36 +00002162Internals
2163
2164- On Unix, fix code for finding Python installation directory so that
2165 it works when argv[0] is a relative path.
2166
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002167- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002168 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002169 rather than by generating a copy of the object.
2170
Tim Peters482c0212000-09-26 06:33:09 +00002171- Several of the internal Unicode tables are much smaller now, and
2172 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002173
Jeremy Hylton97693b02000-09-26 17:42:51 +00002174- In the garbage collector: Fixed bug in collection of tuples. Fixed
2175 bug that caused some instances to be removed from the container set
2176 while they were still live. Fixed parsing in gc.set_debug() for
2177 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002178
2179- Fixed refcount problem in instance deallocation that only occurred
2180 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2181
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002182- On Windows, getpythonregpath is now protected against null data in
2183 registry key.
2184
2185- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002186 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002187
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002188
Jeremy Hylton1b618592000-09-26 05:32:36 +00002189Build and platform-specific issues
2190
2191- Better support of GNU Pth via --with-pth configure option.
2192
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002193- Python/C API now properly exposed to dynamically-loaded extension
2194 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002195
2196- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2197 Don't define MS_SYNC to be zero when it is undefined. Added missing
2198 prototypes in posixmodule.c.
2199
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002200- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002201 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002202
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002203- Fix largefile support on older NetBSD systems and OpenBSD by adding
2204 define for TELL64.
2205
2206
2207Tools and other miscellany
2208
2209- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2210
2211- freeze: The modulefinder now works with 2.0 opcodes.
2212
Tim Petersa3a3a032000-11-30 05:22:44 +00002213- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002214 Move hackery of sys.argv until after the Tk instance has been
2215 created, which allows the application-specific Tkinter
2216 initialization to be executed if present; also pass an explicit
2217 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002218
Jeremy Hylton1b618592000-09-26 05:32:36 +00002219
2220What's new in 2.0 beta 1?
2221=========================
2222
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002223Source Incompatibilities
2224------------------------
2225
2226None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2227such as single-argument append(), connect() and bind(), and changes to
2228str(long) and repr(float).
2229
2230
2231Binary Incompatibilities
2232------------------------
2233
2234- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2235with Python 2.0; these extensions will have to be rebuilt for Python
22362.0.
2237
2238- On Windows, attempting to import a third party extension built for
2239Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2240can do about this. Check your PYTHONPATH environment variable!
2241
2242- Python bytecode files (*.pyc and *.pyo) are not compatible between
2243releases.
2244
2245
2246Overview of Changes Since 1.6
2247-----------------------------
2248
2249There are many new modules (including brand new XML support through
2250the xml package, and i18n support through the gettext module); a list
2251of all new modules is included below. Lots of bugs have been fixed.
2252
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002253The process for making major new changes to the language has changed
2254since Python 1.6. Enhancements must now be documented by a Python
2255Enhancement Proposal (PEP) before they can be accepted.
2256
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002257There are several important syntax enhancements, described in more
2258detail below:
2259
2260 - Augmented assignment, e.g. x += 1
2261
2262 - List comprehensions, e.g. [x**2 for x in range(10)]
2263
2264 - Extended import statement, e.g. import Module as Name
2265
2266 - Extended print statement, e.g. print >> file, "Hello"
2267
2268Other important changes:
2269
2270 - Optional collection of cyclical garbage
2271
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002272Python Enhancement Proposal (PEP)
2273---------------------------------
2274
2275PEP stands for Python Enhancement Proposal. A PEP is a design
2276document providing information to the Python community, or describing
2277a new feature for Python. The PEP should provide a concise technical
2278specification of the feature and a rationale for the feature.
2279
2280We intend PEPs to be the primary mechanisms for proposing new
2281features, for collecting community input on an issue, and for
2282documenting the design decisions that have gone into Python. The PEP
2283author is responsible for building consensus within the community and
2284documenting dissenting opinions.
2285
2286The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002287
2288Augmented Assignment
2289--------------------
2290
2291This must have been the most-requested feature of the past years!
2292Eleven new assignment operators were added:
2293
Guido van Rossume905e952000-09-05 12:42:46 +00002294 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002295
2296For example,
2297
2298 A += B
2299
2300is similar to
2301
2302 A = A + B
2303
2304except that A is evaluated only once (relevant when A is something
2305like dict[index].attr).
2306
2307However, if A is a mutable object, A may be modified in place. Thus,
2308if A is a number or a string, A += B has the same effect as A = A+B
2309(except A is only evaluated once); but if a is a list, A += B has the
2310same effect as A.extend(B)!
2311
2312Classes and built-in object types can override the new operators in
2313order to implement the in-place behavior; the not-in-place behavior is
2314used automatically as a fallback when an object doesn't implement the
2315in-place behavior. For classes, the method name is derived from the
2316method name for the corresponding not-in-place operator by inserting
2317an 'i' in front of the name, e.g. __iadd__ implements in-place
2318__add__.
2319
2320Augmented assignment was implemented by Thomas Wouters.
2321
2322
2323List Comprehensions
2324-------------------
2325
2326This is a flexible new notation for lists whose elements are computed
2327from another list (or lists). The simplest form is:
2328
2329 [<expression> for <variable> in <sequence>]
2330
Guido van Rossum56db0952000-09-06 23:34:25 +00002331For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002332This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002333
2334You can also add a condition:
2335
2336 [<expression> for <variable> in <sequence> if <condition>]
2337
2338For example, [w for w in words if w == w.lower()] would yield the list
2339of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002340than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002341
2342You can also have nested for loops and more than one 'if' clause. For
2343example, here's a function that flattens a sequence of sequences::
2344
2345 def flatten(seq):
2346 return [x for subseq in seq for x in subseq]
2347
2348 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2349
2350This prints
2351
2352 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2353
2354List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002355Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002356
2357
2358Extended Import Statement
2359-------------------------
2360
2361Many people have asked for a way to import a module under a different
2362name. This can be accomplished like this:
2363
2364 import foo
2365 bar = foo
2366 del foo
2367
2368but this common idiom gets old quickly. A simple extension of the
2369import statement now allows this to be written as follows:
2370
2371 import foo as bar
2372
2373There's also a variant for 'from ... import':
2374
2375 from foo import bar as spam
2376
2377This also works with packages; e.g. you can write this:
2378
2379 import test.regrtest as regrtest
2380
2381Note that 'as' is not a new keyword -- it is recognized only in this
2382context (this is only possible because the syntax for the import
2383statement doesn't involve expressions).
2384
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002385Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002386
2387
2388Extended Print Statement
2389------------------------
2390
2391Easily the most controversial new feature, this extension to the print
2392statement adds an option to make the output go to a different file
2393than the default sys.stdout.
2394
2395For example, to write an error message to sys.stderr, you can now
2396write:
2397
2398 print >> sys.stderr, "Error: bad dog!"
2399
2400As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002401evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002402
2403 print >> None, "Hello world"
2404
2405is equivalent to
2406
2407 print "Hello world"
2408
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002409Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002410
2411
2412Optional Collection of Cyclical Garbage
2413---------------------------------------
2414
2415Python is now equipped with a garbage collector that can hunt down
2416cyclical references between Python objects. It's no replacement for
2417reference counting; in fact, it depends on the reference counts being
2418correct, and decides that a set of objects belong to a cycle if all
2419their reference counts can be accounted for from their references to
2420each other. This devious scheme was first proposed by Eric Tiedemann,
2421and brought to implementation by Neil Schemenauer.
2422
2423There's a module "gc" that lets you control some parameters of the
2424garbage collection. There's also an option to the configure script
2425that lets you enable or disable the garbage collection. In 2.0b1,
2426it's on by default, so that we (hopefully) can collect decent user
2427experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002428performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002429off by default in the final 2.0 release.
2430
2431
2432Smaller Changes
2433---------------
2434
2435A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2436map(None, seq1, seq2, ...) when the sequences have the same length;
2437i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2438the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002439zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002440
2441sys.version_info is a tuple (major, minor, micro, level, serial).
2442
2443Dictionaries have an odd new method, setdefault(key, default).
2444dict.setdefault(key, default) returns dict[key] if it exists; if not,
2445it sets dict[key] to default and returns that value. Thus:
2446
2447 dict.setdefault(key, []).append(item)
2448
2449does the same work as this common idiom:
2450
2451 if not dict.has_key(key):
2452 dict[key] = []
2453 dict[key].append(item)
2454
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002455There are two new variants of SyntaxError that are raised for
2456indentation-related errors: IndentationError and TabError.
2457
2458Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2459escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002460
2461The limits on the size of expressions and file in Python source code
2462have been raised from 2**16 to 2**32. Previous versions of Python
2463were limited because the maximum argument size the Python VM accepted
2464was 2**16. This limited the size of object constructor expressions,
2465e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2466limit was raised thanks to a patch by Charles Waldman that effectively
2467fixes the problem. It is now much more likely that you will be
2468limited by available memory than by an arbitrary limit in Python.
2469
2470The interpreter's maximum recursion depth can be modified by Python
2471programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2472limit is the maximum number of recursive calls that can be made by
2473Python code. The limit exists to prevent infinite recursion from
2474overflowing the C stack and causing a core dump. The default value is
24751000. The maximum safe value for a particular platform can be found
2476by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002477
2478New Modules and Packages
2479------------------------
2480
2481atexit - for registering functions to be called when Python exits.
2482
2483imputil - Greg Stein's alternative API for writing custom import
2484hooks.
2485
2486pyexpat - an interface to the Expat XML parser, contributed by Paul
2487Prescod.
2488
2489xml - a new package with XML support code organized (so far) in three
2490subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2491would fill a volume. There's a special feature whereby a
2492user-installed package named _xmlplus overrides the standard
2493xmlpackage; this is intended to give the XML SIG a hook to distribute
2494backwards-compatible updates to the standard xml package.
2495
2496webbrowser - a platform-independent API to launch a web browser.
2497
2498
Guido van Rossume905e952000-09-05 12:42:46 +00002499Changed Modules
2500---------------
2501
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002502array -- new methods for array objects: count, extend, index, pop, and
2503remove
2504
2505binascii -- new functions b2a_hex and a2b_hex that convert between
2506binary data and its hex representation
2507
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002508calendar -- Many new functions that support features including control
2509over which day of the week is the first day, returning strings instead
2510of printing them. Also new symbolic constants for days of week,
2511e.g. MONDAY, ..., SUNDAY.
2512
2513cgi -- FieldStorage objects have a getvalue method that works like a
2514dictionary's get method and returns the value attribute of the object.
2515
2516ConfigParser -- The parser object has new methods has_option,
2517remove_section, remove_option, set, and write. They allow the module
2518to be used for writing config files as well as reading them.
2519
2520ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002521optionally support the RFC 959 REST command.
2522
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002523gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002524
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002525httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2526the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002527
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002528locale -- implement getdefaultlocale for Win32 and Macintosh
2529
2530marshal -- no longer dumps core when marshaling deeply nested or
2531recursive data structures
2532
2533os -- new functions isatty, seteuid, setegid, setreuid, setregid
2534
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002535os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2536support under Unix.
2537
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002538os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002539
2540os.path -- fix semantics of os.path.commonprefix
2541
2542smtplib -- support for sending very long messages
2543
2544socket -- new function getfqdn()
2545
2546readline -- new functions to read, write and truncate history files.
2547The readline section of the library reference manual contains an
2548example.
2549
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002550select -- add interface to poll system call
2551
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002552shutil -- new copyfileobj function
2553
2554SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2555HTTP server.
2556
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002557Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002558
2559urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002560e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002561
2562whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002563
2564
2565Obsolete Modules
2566----------------
2567
2568None. However note that 1.6 made a whole slew of modules obsolete:
2569stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2570poly, zmod, strop, util, whatsound.
2571
2572
2573Changed, New, Obsolete Tools
2574----------------------------
2575
Tim Peters8b092332000-09-05 20:15:25 +00002576None.
Guido van Rossume905e952000-09-05 12:42:46 +00002577
2578
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002579C-level Changes
2580---------------
2581
2582Several cleanup jobs were carried out throughout the source code.
2583
2584All C code was converted to ANSI C; we got rid of all uses of the
2585Py_PROTO() macro, which makes the header files a lot more readable.
2586
2587Most of the portability hacks were moved to a new header file,
2588pyport.h; several other new header files were added and some old
2589header files were removed, in an attempt to create a more rational set
2590of header files. (Few of these ever need to be included explicitly;
2591they are all included by Python.h.)
2592
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002593Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002594and Win64, especially for the new Intel Itanium processor. Mick also
2595added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002596
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002597The C APIs to return an object's size have been update to consistently
2598use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2599previous versions, the abstract interfaces used PyXXX_Length and the
2600concrete interfaces used PyXXX_Size. The old names,
2601e.g. PyObject_Length, are still available for backwards compatibility
2602at the API level, but are deprecated.
2603
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002604The PyOS_CheckStack function has been implemented on Windows by
2605Fredrik Lundh. It prevents Python from failing with a stack overflow
2606on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002607
2608The GC changes resulted in creation of two new slots on object,
2609tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002610the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002611
2612The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002613C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002614
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002615PyErr_Format has been updated to automatically calculate the size of
2616the buffer needed to hold the formatted result string. This change
2617prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002618
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002619New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002620
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002621PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2622that are the same as their non-Ex counterparts except they take an
2623extra flag argument that tells them to close the file when done.
2624
2625XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002626
Tim Peters8b092332000-09-05 20:15:25 +00002627
2628Windows Changes
2629---------------
2630
2631New popen2/popen3/peopen4 in os module (see Changed Modules above).
2632
2633os.popen is much more usable on Windows 95 and 98. See Microsoft
2634Knowledge Base article Q150956. The Win9x workaround described there
2635is implemented by the new w9xpopen.exe helper in the root of your
2636Python installation. Note that Python uses this internally; it is not
2637a standalone program.
2638
2639Administrator privileges are no longer required to install Python
2640on Windows NT or Windows 2000. If you have administrator privileges,
2641Python's registry info will be written under HKEY_LOCAL_MACHINE.
2642Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002643under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002644uses of Python, but will prevent some advanced uses from working
2645(for example, running a Python script as an NT service, or possibly
2646from CGI).
2647
2648[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2649installer; instead, it installs the needed Tcl/Tk files directly in the
2650Python directory. If you already have a Tcl/Tk installation, this
2651wastes some disk space (about 4 Megs) but avoids problems with
2652conflicting Tcl/Tk installations, and makes it much easier for Python
2653to ensure that Tcl/Tk can find all its files.
2654
2655[This was new in 1.6] The Windows installer now installs by default in
2656\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2657
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002658
2659Updates to the changes between 1.5.2 and 1.6
2660--------------------------------------------
2661
2662The 1.6 NEWS file can't be changed after the release is done, so here
2663is some late-breaking news:
2664
2665New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2666and changes to getlocale() and setlocale().
2667
2668The new module is now enabled per default.
2669
2670It is not true that the encodings codecs cannot be used for normal
2671strings: the string.encode() (which is also present on 8-bit strings
2672!) allows using them for 8-bit strings too, e.g. to convert files from
2673cp1252 (Windows) to latin-1 or vice-versa.
2674
2675Japanese codecs are available from Tamito KAJIYAMA:
2676http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2677
2678
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002679======================================================================