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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
7Core
8
9Library
10
11Tools
12
13Build
14
15C API
16
17New platforms
18
19Tests
20
21Windows
22
23
Tim Petersb07352e2001-09-08 01:25:47 +000024What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +000025Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +000026===========================
27
Guido van Rossum808eea72001-09-25 04:15:41 +000028Type/class unification and new-style classes
29
30- pydoc and inspect are now aware of new-style classes;
31 e.g. help(list) at the interactive prompt now shows proper
32 documentation for all operations on list objects.
33
34- Applications using Jim Fulton's ExtensionClass module can now safely
35 be used with Python 2.2. In particular, Zope 2.4.1 now works with
36 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
37 examples also work again. It is hoped that Gtk and Boost also work
38 with 2.2a4 and beyond. (If you can confirm this, please write
39 webmaster@python.org; if there are still problems, please open a bug
40 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +000041
Tim Peters66c1a522001-09-24 21:17:50 +000042- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
43 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
44 in the constructed property object. fget, fset and fdel weren't
45 discoverable from Python in 2.2a3. __doc__ is new, and allows to
46 associate a docstring with a property.
47
Guido van Rossum808eea72001-09-25 04:15:41 +000048- Comparison overloading is now more completely implemented. For
49 example, a str subclass instance can properly be compared to a str
50 instance, and it can properly overload comparison. Ditto for most
51 other built-in object types.
52
53- The repr() of new-style classes has changed; instead of <type
54 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
55 *except* for built-in types, which are still rendered as <type
56 'Foo'> (to avoid upsetting existing code that might parse or
57 otherwise rely on repr() of certain type objects).
58
59- The repr() of new-style objects is now always <Foo object at XXX>;
60 previously, it was sometimes <Foo instance at XXX>.
61
62- For new-style classes, what was previously called __getattr__ is now
63 called __getattribute__. This method, if defined, is called for
64 *every* attribute access. A new __getattr__ hook mor similar to the
65 one in classic classes is defined which is called only if regular
66 attribute access raises AttributeError; to catch *all* attribute
67 access, you can use __getattribute__ (for new-style classes). If
68 both are defined, __getattribute__ is called first, and if it raises
69 AttributeError, __getattr__ is called.
70
71- The __class__ attribute of new-style objects can be assigned to.
72 The new class must have the same C-level object layout as the old
73 class.
74
75- The builtin file type can be subclassed now. In the usual pattern,
76 "file" is the name of the builtin type, and file() is a new builtin
77 constructor, with the same signature as the builtin open() function.
78 file() is now the preferred way to open a file.
79
80- Previously, __new__ would only see sequential arguments passed to
81 the type in a constructor call; __init__ would see both sequential
82 and keyword arguments. This made no sense whatsoever any more, so
83 now both __new__ and __init__ see all arguments.
84
85- Previously, hash() applied to an instance of a subclass of str or
86 unicode always returned 0. This has been repaired.
87
88- Previously, an operation on an instance of a subclass of an
89 immutable type (int, long, float, complex, tuple, str, unicode),
90 where the subtype didn't override the operation (and so the
91 operation was handled by the builtin type), could return that
92 instance instead a value of the base type. For example, if s was of
93 a str sublass type, s[:] returned s as-is. Now it returns a str
94 with the same value as s.
95
Barry Warsaw86fbaf82001-09-28 15:26:12 +000096- Provisional support for pickling new-style objects has been added.
97
Guido van Rossum808eea72001-09-25 04:15:41 +000098Core
99
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000100- file.writelines() now accepts any iterable object producing strings.
101
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000102- PyUnicode_FromEncodedObject() now works very much like
103 PyObject_Str(obj) in that it tries to use __str__/tp_str
104 on the object if the object is not a string or buffer. This
105 makes unicode() behave like str() when applied to non-string/buffer
106 objects.
107
Martin v. Löwis2777c022001-09-19 13:47:32 +0000108- PyFile_WriteObject now passes Unicode object to the file's write
109 method. As a result, all file-like object which may be the target
110 of a print statement must support Unicode objects, i.e. they must
111 at least convert them into ASCII strings.
112
Guido van Rossum624c8af2001-09-18 15:21:04 +0000113- Thread scheduling on Solaris should be improved; it is no longer
114 necessary to insert a small sleep at the start of a thread in order
115 to let other runnable threads be scheduled.
116
Tim Petersb07352e2001-09-08 01:25:47 +0000117Library
118
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000119- StringIO.StringIO instances and cStringIO.StringIO instances support
120 read character buffer compatible objects for their .write() methods.
121 These objects are converted to strings and then handled as such
122 by the instances.
123
Barry Warsaw2f600732001-09-24 04:28:10 +0000124- The "email" package has been added. This is basically a port of the
125 mimelib package <http://sf.net/projects/mimelib> with API changes
126 and some implementations updated to use iterators and generators.
127
Tim Peters8a9c2842001-09-22 21:30:22 +0000128- difflib.ndiff() and difflib.Differ.compare() are generators now. This
129 restores the ability of Tools/scripts/ndiff.py to start producing output
130 before the entire comparison is complete.
131
Barry Warsaw58b072d2001-09-22 04:44:21 +0000132- StringIO.StringIO instances and cStringIO.StringIO instances support
133 iteration just like file objects (i.e. their .readline() method is
134 called for each iteration until it returns an empty string).
135
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000136- The codecs module has grown four new helper APIs to access
137 builtin codecs: getencoder(), getdecoder(), getreader(),
138 getwriter().
139
Guido van Rossum624c8af2001-09-18 15:21:04 +0000140- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
141 simplifies writing XML RPC servers.
142
Barry Warsaw647d5e82001-09-28 17:01:02 +0000143- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000144 after interpretation of symbolic links. On non-Unix systems, this
145 is an alias for os.path.abspath().
146
Tim Peters16a77ad2001-09-08 04:00:12 +0000147- operator.indexOf() (PySequence_Index() in the C API) now works with any
148 iterable object.
149
Guido van Rossum624c8af2001-09-18 15:21:04 +0000150- smtplib now supports various authentication and security features of
151 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000152
Guido van Rossum624c8af2001-09-18 15:21:04 +0000153- hmac: a new module implementing keyed hashing for message
154 authentication.
155
156- mimetypes now recognizes more extensions and file types. At the
157 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000158
Guido van Rossum624c8af2001-09-18 15:21:04 +0000159- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000160 Python 2.2 bytecode generation. It has also been promoted from a
161 Tool to a standard library package. (Tools/compiler still exists as
162 a sample driver.)
163
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000164Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000165
Tim Petersb07352e2001-09-08 01:25:47 +0000166Build
167
Guido van Rossum624c8af2001-09-18 15:21:04 +0000168- Large file support (LFS) is now automatic when the platform supports
169 it; no more manual configuration tweaks are needed. On Linux, at
170 least, it's possible to have a system whose C library supports large
171 files but whose kernel doesn't; in this case, large file support is
172 still enabled but doesn't do you any good unless you upgrade your
173 kernel or share your Python executable with another system whose
174 kernel has large file support.
175
176- The configure script now supplies plausible defaults in a
177 cross-compilation environment. This doesn't mean that the supplied
178 values are always correct, or that cross-compilation now works
179 flawlessly -- but it's a first step (and it shuts up most of
180 autoconf's warnings about AC_TRY_RUN).
181
182- The Unix build is now a bit less chatty, courtesy of the parser
183 generator. The build is completely silent (except for errors) when
184 using "make -s", thanks to a -q option to setup.py.
185
Tim Petersb07352e2001-09-08 01:25:47 +0000186C API
187
Guido van Rossum624c8af2001-09-18 15:21:04 +0000188- The "structmember" API now supports some new flag bits to deny read
189 and/or write access to attributes in restricted execution mode.
190
Tim Petersb07352e2001-09-08 01:25:47 +0000191New platforms
192
Guido van Rossum624c8af2001-09-18 15:21:04 +0000193- Compaq's iPAQ handheld, running the "familiar" Linux distribution
194 (http://familiar.handhelds.org).
195
Tim Petersb07352e2001-09-08 01:25:47 +0000196Tests
197
Tim Peters8a9c2842001-09-22 21:30:22 +0000198- The "classic" standard tests, which work by comparing stdout to
199 an expected-output file under Lib/test/output/, no longer stop at
200 the first mismatch. Instead the test is run to completion, and a
201 variant of ndiff-style comparison is used to report all differences.
202 This is much easier to understand than the previous style of reporting.
203
204- The unittest-based standard tests now use regrtest's test_main()
205 convention, instead of running as a side-effect of merely being
206 imported. This allows these tests to be run in more natural and
207 flexible ways as unittests, outside the regrtest framework.
208
209- regrtest.py is much better integrated with unittest and doctest now,
210 especially in regard to reporting errors.
211
Tim Petersb07352e2001-09-08 01:25:47 +0000212Windows
213
Guido van Rossum624c8af2001-09-18 15:21:04 +0000214- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000215 that support it (NTFS under Windows 2000). See "What's New in
216 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000217
Tim Petersb07352e2001-09-08 01:25:47 +0000218
Tim Petersedc99312001-08-22 21:36:50 +0000219What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000220Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000221===========================
222
223Core
224
Tim Peters9fffa3e2001-09-04 05:14:19 +0000225- Conversion of long to float now raises OverflowError if the long is too
226 big to represent as a C double.
227
Tim Peters32f453e2001-09-03 08:35:41 +0000228- The 3-argument builtin pow() no longer allows a third non-None argument
229 if either of the first two arguments is a float, or if both are of
230 integer types and the second argument is negative (in which latter case
231 the arguments are converted to float, so this is really the same
232 restriction).
233
Tim Peters5d2b77c2001-09-03 05:47:38 +0000234- The builtin dir() now returns more information, and sometimes much
235 more, generally naming all attributes of an object, and all attributes
236 reachable from the object via its class, and from its class's base
237 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
238 an empty list. In 2.2a3,
239
240 >>> dir([])
241 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
242 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
243 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
244 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
245 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
246 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
247 'reverse', 'sort']
248
249 dir(module) continues to return only the module's attributes, though.
250
Tim Petersbdee63f2001-09-02 03:40:59 +0000251- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000252 than raising OverflowError. This is a partial implementation of PEP
253 237. You can use -Wdefault::OverflowWarning to enable a warning for
254 this situation, and -Werror::OverflowWarning to revert to the old
255 OverflowError exception.
256
Guido van Rossum61c345f2001-09-04 03:26:15 +0000257- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000258 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000259 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
260 -Qold, meaning the / operator has its classic meaning and no
261 warnings are issued. Using -Qwarn issues a run-time warning about
262 all uses of classic division for int and long arguments; -Qwarnall
263 also warns about classic division for float and complex arguments
264 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
265 new division by default, but only in the __main__ module. You can
266 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
267 __main__ module new division, and warns about classic division
268 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000269
Tim Petersbdee63f2001-09-02 03:40:59 +0000270- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000271 long, float, str, unicode, and tuple. (The types complex, list and
272 dictionary can also be subclassed; this was introduced earlier.)
273 Note that restrictions apply when subclassing immutable built-in
274 types: you can only affect the value of the instance by overloading
275 __new__. You can add mutable attributes, and the subclass instances
276 will have a __dict__ attribute, but you cannot change the "value"
277 (as implemented by the base class) of an immutable subclass instance
278 once it is created.
279
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000280- The dictionary constructor now takes an optional argument, a
281 mapping-like object, and initializes the dictionary from its
282 (key, value) pairs.
283
Tim Petersbdee63f2001-09-02 03:40:59 +0000284- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000285 "cooperative super calls" in a multiple inheritance setting. For an
286 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
287
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000288- A new built-in type, property, has been added. This enables the
289 creation of "properties". These are attributes implemented by
290 getter and setter functions (or only one of these for read-only or
291 write-only attributes), without the need to override __getattr__.
292 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000293
Tim Petersbdee63f2001-09-02 03:40:59 +0000294- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000295 liberalized, to allow leading zeroes. Examples of literals now
296 legal that were SyntaxErrors before:
297
298 00.0 0e3 0100j 07.5 00000000000000000008.
299
Tim Petersbdee63f2001-09-02 03:40:59 +0000300- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000301 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
302
Tim Petersedc99312001-08-22 21:36:50 +0000303Library
304
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000305- telnetlib includes symbolic names for the options, and support for
306 setting an option negotiation callback.
307
Tim Petersa40c7932001-09-05 22:36:56 +0000308- The new C standard no longer requires that math libraries set errno to
309 ERANGE on overflow. For platform libraries that exploit this new
310 freedom, Python's overflow-checking was wholly broken. A new overflow-
311 checking scheme attempts to repair that, but may not be reliable on all
312 platforms (C doesn't seem to provide anything both useful and portable
313 in this area anymore).
314
Martin v. Löwis44f86962001-09-05 13:44:54 +0000315- Asynchronous timeout actions are available through the new class
316 threading.Timer.
317
Tim Peters78526162001-09-05 00:53:45 +0000318- math.log and math.log10 now return sensible results for even huge
319 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
320
Tim Petersbdee63f2001-09-02 03:40:59 +0000321- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000322 currently held. See the docs for the imp module.
323
Tim Petersbdee63f2001-09-02 03:40:59 +0000324- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000325 dumps containing ints written on platforms where Python ints are 8 bytes.
326 When read on a box where Python ints are 4 bytes, such values are
327 converted to Python longs.
328
Tim Petersbdee63f2001-09-02 03:40:59 +0000329- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000330 code objects is no longer allowed. This plugs a security hole.
331
Steve Purcell6091cd62001-09-06 16:05:17 +0000332- unittest.TestResult instances no longer store references to tracebacks
333 generated by test failures. This prevents unexpected dangling references
334 to objects that should be garbage collected between tests.
335
Tim Petersedc99312001-08-22 21:36:50 +0000336Tools
337
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000338- Tools/scripts/fixdiv.py has been added which can be used to fix
339 division operators as per PEP 238.
340
Tim Petersedc99312001-08-22 21:36:50 +0000341Build
342
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000343- If you are an adventurous person using Mac OS X you may want to look at
344 Mac/OSX. There is a Makefile there that will build Python as a real Mac
345 application, which can be used for experimenting with Carbon or Cocoa.
346 Discussion of this on pythonmac-sig, please.
347
Tim Peters7eea37e2001-09-04 22:08:56 +0000348C API
349
350- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000351
Tim Peters9fffa3e2001-09-04 05:14:19 +0000352- Note that PyLong_AsDouble can fail! This has always been true, but no
353 callers checked for it. It's more likely to fail now, because overflow
354 errors are properly detected now. The proper way to check:
355
356 double x = PyLong_AsDouble(some_long_object);
357 if (x == -1.0 && PyErr_Occurred()) {
358 /* The conversion failed. */
359 }
360
Tim Petersbdee63f2001-09-02 03:40:59 +0000361- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000362 compile but will not participate in GC. To upgrade an extension
363 module:
364
365 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000366
Neil Schemenauer4042c692001-08-30 15:38:01 +0000367 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
368 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000369
Neil Schemenauer4042c692001-08-30 15:38:01 +0000370 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
371 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000372
Neil Schemenauer4042c692001-08-30 15:38:01 +0000373 - remove PyGC_HEAD_SIZE from object size calculations
374
375 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
376
Tim Petersbdee63f2001-09-02 03:40:59 +0000377- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000378 These can be used safely to construct string objects from a
379 sprintf-style format string (similar to the format string supported
380 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000381
Tim Petersedc99312001-08-22 21:36:50 +0000382New platforms
383
Tim Petersb7da0902001-09-02 23:01:43 +0000384- Stephen Hansen contributed patches sufficient to get a clean compile
385 under Borland C (Windows), but he reports problems running it and ran
386 out of time to complete the port. Volunteers? Expect a MemoryError
387 when importing the types module; this is probably shallow, and
388 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000389
Tim Petersedc99312001-08-22 21:36:50 +0000390Tests
391
392Windows
393
Tim Peters6e13a562001-09-06 00:32:15 +0000394- Large file support is now enabled on Win32 platforms as well as on
395 Win64. This means that, for example, you can use f.tell() and f.seek()
396 to manipulate files larger than 2 gigabytes (provided you have enough
397 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000398 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
399 filesize limit, and large file support makes no difference there.
400 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
401 NTFS has no practical limit on file size, and files of any size can be
402 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000403
Tim Petersbdee63f2001-09-02 03:40:59 +0000404- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000405 points to command.com (patch from Brian Quinlan).
406
Tim Petersedc99312001-08-22 21:36:50 +0000407
Tim Peters20f51a72001-07-21 02:31:40 +0000408What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000409Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000410===========================
411
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000412Build
413
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000414- Tim Peters developed a brand new Windows installer using Wise 8.1,
415 generously donated to us by Wise Solutions.
416
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000417- configure supports a new option --enable-unicode, with the values
418 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
419 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000420
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000421- A new configure option --enable-framework builds a Mac OS X framework,
422 which "make frameworkinstall" will install. This provides a starting
423 point for more mac-like functionality, join pythonmac-sig@python.org
424 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000425
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000426- The NeXT platform is no longer supported.
427
428- The `new' module is now statically linked.
429
Tim Peters0afb6092001-08-15 06:06:44 +0000430Tools
431
432- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000433 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000434 the module docstring for details.
435
Tim Peters20f51a72001-07-21 02:31:40 +0000436Tests
437
Tim Peters5e824c32001-08-12 22:25:01 +0000438- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000439 platforms, allowing to give clearer test result output. regrtest
440 also has optional --use/-u switch to run normally disabled tests
441 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000442
Tim Peters20f51a72001-07-21 02:31:40 +0000443- Several new tests in the standard test suite, with special thanks to
444 Nick Mathewson.
445
446Core
447
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000448- The floor division operator // has been added as outlined in PEP
449 238. The / operator still provides classic division (and will until
450 Python 3.0) unless "from __future__ import division" is included, in
451 which case the / operator will provide true division. The operator
452 module provides truediv() and floordiv() functions. Augmented
453 assignment variants are included, as are the equivalent overloadable
454 methods and C API methods. See the PEP for a full discussion:
455 <http://python.sf.net/peps/pep-0238.html>
456
Tim Peters6cd6a822001-08-17 22:11:27 +0000457- Future statements are now effective in simulated interactive shells
458 (like IDLE). This should "just work" by magic, but read Michael
459 Hudson's "Future statements in simulated shells" PEP 264 for full
460 details: <http://python.sf.net/peps/pep-0264.html>.
461
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000462- The type/class unification (PEP 252-253) was integrated into the
463 trunk and is not so tentative any more (the exact specification of
464 some features is still tentative). A lot of work has done on fixing
465 bugs and adding robustness and features (performance still has to
466 come a long way).
467
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000468- Warnings about a mismatch in the Python API during extension import
469 now use the Python warning framework (which makes it possible to
470 write filters for these warnings).
471
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000472- A function's __dict__ (aka func_dict) will now always be a
473 dictionary. It used to be possible to delete it or set it to None,
474 but now both actions raise TypeErrors. It is still legal to set it
475 to a dictionary object. Getting func.__dict__ before any attributes
476 have been assigned now returns an empty dictionary instead of None.
477
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000478- A new command line option, -E, was added which disables the use of
479 all environment variables, or at least those that are specifically
480 significant to Python. Usually those have a name starting with
481 "PYTHON". This was used to fix a problem where the tests fail if
482 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
483 older distribution.
484
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000485Library
486
Tim Peters5e824c32001-08-12 22:25:01 +0000487- New class Differ and new functions ndiff() and restore() in difflib.py.
488 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000489 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000490
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000491- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
492 value using the minimal quoting required for the value; more
493 reliable than using xml.sax.saxutils.escape() for attribute values.
494
495- Readline completion support for cmd.Cmd was added.
496
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000497- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
498
499- Added function threading.BoundedSemaphore()
500
501- Added Ka-Ping Yee's cgitb.py module.
502
503- The `new' module now exposes the CO_xxx flags.
504
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000505New platforms
506
507C API
508
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000509- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
510 which provide a cross-platform implementations for the
511 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
512 the standard sprintf() and vsprintf() C lib APIs, these versions
513 apply bounds checking on the used buffer which enhances protection
514 against buffer overruns.
515
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000516- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000517 and extensions using different Unicode widths is rendered next to
518 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000519 will result in an ImportError. Unicode extensions writers must make
520 sure to check the Unicode width compatibility in their extensions by
521 using at least one of the mangled Unicode APIs in the extension.
522
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000523- Two new flags METH_NOARGS and METH_O are available in method definition
524 tables to simplify implementation of methods with no arguments and a
525 single untyped argument. Calling such methods is more efficient than
526 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
527 deprecated.
528
Tim Petersc1731372001-08-04 08:12:36 +0000529Windows
530
531- "import module" now compiles module.pyw if it exists and nothing else
532 relevant is found.
533
Tim Peters20f51a72001-07-21 02:31:40 +0000534
Guido van Rossum55a78992001-07-17 17:22:32 +0000535What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +0000536===========================
537
538Core
Tim Petersa814db52001-05-14 07:05:58 +0000539
Tim Peters6d6c1a32001-08-02 04:15:00 +0000540- TENTATIVELY, a large amount of code implementing much of what's
541 described in PEP 252 (Making Types Look More Like Classes) and PEP
542 253 (Subtyping Built-in Types) was added. This will be released
543 with Python 2.2a1. Documentation will be provided separately
544 through http://www.python.org/2.2/. The purpose of releasing this
545 with Python 2.2a1 is to test backwards compatibility. It is
546 possible, though not likely, that a decision is made not to release
547 this code as part of 2.2 final, if any serious backwards
548 incompapatibilities are found during alpha testing that cannot be
549 repaired.
550
Guido van Rossum55a78992001-07-17 17:22:32 +0000551- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000552 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000553 more 'yield' statements. See PEP 255. Since this adds a new
554 keyword to the language, this feature must be enabled by including a
555 future statement: "from __future__ import generators" (see PEP 236).
556 Generators will become a standard feature in a future release
557 (probably 2.3). Without this future statement, 'yield' remains an
558 ordinary identifier, but a warning is issued each time it is used.
559 (These warnings currently don't conform to the warnings framework of
560 PEP 230; we intend to fix this in 2.2a2.)
561
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000562- The UTF-16 codec was modified to be more RFC compliant. It will now
563 only remove BOM characters at the start of the string and then
564 only if running in native mode (UTF-16-LE and -BE won't remove a
565 leading BMO character).
566
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000567- Strings now have a new method .decode() to complement the already
568 existing .encode() method. These two methods provide direct access
569 to the corresponding decoders and encoders of the registered codecs.
570
571 To enhance the usability of the .encode() method, the special
572 casing of Unicode object return values was dropped (Unicode objects
573 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000574
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000575 Both methods will now return whatever the codec in charge of the
576 requested encoding returns as object, e.g. Unicode codecs will
577 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
578 will return u"äöü"). This enables codec writer to create codecs
579 for various simple to use conversions.
580
581 New codecs were added to demonstrate these new features (the .encode()
582 and .decode() columns indicate the type of the returned objects):
583
584 Name | .encode() | .decode() | Description
585 ----------------------------------------------------------------------
586 uu | string | string | UU codec (e.g. for email)
587 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000588 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000589 zlib | string | string | zlib compression
590 hex | string | string | 2-byte hex codec
591 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
592
Mark Hammond2a0af792001-05-14 03:09:36 +0000593- Some operating systems now support the concept of a default Unicode
594 encoding for file system operations. Notably, Windows supports 'mbcs'
595 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000596 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000597 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000598
599 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000600 functions that return filenames (such as os.listdir()) to return Python
601 string objects pre-encoded using the default file system encoding for
602 the platform. As this encoding is likely to be different from Python's
603 default encoding, converting this name to a Unicode object before passing
604 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000605 would attempt to use its default encoding (generally ASCII) rather than
606 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000607
Tim Petersa814db52001-05-14 07:05:58 +0000608 In general, this change simply removes surprises when working with
609 Unicode and the file system, making these operations work as you expect,
610 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000611 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000612
Tim Peters61dff2b2001-05-08 15:43:37 +0000613- Float (and complex) literals in source code were evaluated to full
614 precision only when running from a .py file; the same code loaded from a
615 .pyc (or .pyo) file could suffer numeric differences starting at about the
616 12th significant decimal digit. For example, on a machine with IEEE-754
617 floating arithmetic,
618
619 x = 9007199254740992.0
620 print long(x)
621
622 printed 9007199254740992 if run directly from .py, but 9007199254740000
623 if from a compiled (.pyc or .pyo) file. This was due to marshal using
624 str(float) instead of repr(float) when building code objects. marshal
625 now uses repr(float) instead, which should reproduce floats to full
626 machine precision (assuming the platform C float<->string I/O conversion
627 functions are of good quality).
628
629 This may cause floating-point results to change in some cases, and
630 usually for the better, but may also cause numerically unstable
631 algorithms to break.
632
Tim Peters2f228e72001-05-13 00:19:31 +0000633- The implementation of dicts suffers fewer collisions, which has speed
634 benefits. However, the order in which dict entries appear in dict.keys(),
635 dict.values() and dict.items() may differ from previous releases for a
636 given dict. Nothing is defined about this order, so no program should
637 rely on it. Nevertheless, it's easy to write test cases that rely on the
638 order by accident, typically because of printing the str() or repr() of a
639 dict to an "expected results" file. See Lib/test/test_support.py's new
640 sortdict(dict) function for a simple way to display a dict in sorted
641 order.
642
Tim Peters7a3bfc32001-06-12 01:22:22 +0000643- Many other small changes to dicts were made, resulting in faster
644 operation along the most common code paths.
645
Guido van Rossum10315822001-05-01 20:54:30 +0000646- Dictionary objects now support the "in" operator: "x in dict" means
647 the same as dict.has_key(x).
648
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000649- The update() method of dictionaries now accepts generic mapping
650 objects. Specifically the argument object must support the .keys()
651 and __getitem__() methods. This allows you to say, for example,
652 {}.update(UserDict())
653
Guido van Rossum10315822001-05-01 20:54:30 +0000654- Iterators were added; this is a generalized way of providing values
655 to a for loop. See PEP 234. There's a new built-in function iter()
656 to return an iterator. There's a new protocol to get the next value
657 from an iterator using the next() method (in Python) or the
658 tp_iternext slot (in C). There's a new protocol to get iterators
659 using the __iter__() method (in Python) or the tp_iter slot (in C).
660 Iterating (i.e. a for loop) over a dictionary generates its keys.
661 Iterating over a file generates its lines.
662
Tim Petersf553f892001-05-01 20:45:31 +0000663- The following functions were generalized to work nicely with iterator
664 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000665 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000666 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
667 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000668 join() method of strings
669 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000670 'x in y' and 'x not in y' (PySequence_Contains() in C API)
671 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000672 right-hand side of assignment statements with multiple targets, such as
673 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000674
Tim Petersd85e1022001-05-11 21:51:48 +0000675- Accessing module attributes is significantly faster (for example,
676 random.random or os.path or yourPythonModule.yourAttribute).
677
Tim Peterse63415e2001-05-08 04:38:29 +0000678- Comparing dictionary objects via == and != is faster, and now works even
679 if the keys and values don't support comparisons other than ==.
680
Tim Peters95bf9392001-05-10 08:32:44 +0000681- Comparing dictionaries in ways other than == and != is slower: there were
682 insecurities in the dict comparison implementation that could cause Python
683 to crash if the element comparison routines for the dict keys and/or
684 values mutated the dicts. Making the code bulletproof slowed it down.
685
Tim Peterseb28ef22001-06-02 05:27:19 +0000686- Collisions in dicts are resolved via a new approach, which can help
687 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000688 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000689 faster now. Thanks to Christian Tismer for pointing out the cause and
690 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000691
Tim Peters52e155e2001-06-16 05:42:57 +0000692- repr() is much faster for large containers (dict, list, tuple).
693
694
Tim Petersa814db52001-05-14 07:05:58 +0000695Library
696
Fred Drake960fdf92001-07-20 18:38:26 +0000697- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
698 were added to the string module. These a locale-indenpendent
699 constants, unlike letters, lowercase, and uppercase. These are now
700 use in appropriate locations in the standard library.
701
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000702- The flags used in dlopen calls can now be configured using
703 sys.setdlopenflags and queried using sys.getdlopenflags.
704
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000705- Fredrik Lundh's xmlrpclib is now a standard library module. This
706 provides full client-side XML-RPC support. In addition,
707 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
708 one asyncore-based). Thanks to Eric Raymond for the documentation.
709
Guido van Rossum643d3912001-07-05 14:46:25 +0000710- The xrange() object is simplified: it no longer supports slicing,
711 repetition, comparisons, efficient 'in' checking, the tolist()
712 method, or the start, stop and step attributes. See PEP 260.
713
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000714- A new function fnmatch.filter to filter lists of file names was added.
715
Barry Warsawffd674d2001-05-22 16:00:10 +0000716- calendar.py uses month and day names based on the current locale.
717
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000718- strop is now *really* obsolete (this was announced before with 1.6),
719 and issues DeprecationWarning when used (except for the four items
720 that are still imported into string.py).
721
Tim Petersa814db52001-05-14 07:05:58 +0000722- Cookie.py now sorts key+value pairs by key in output strings.
723
724- pprint.isrecursive(object) didn't correctly identify recursive objects.
725 Now it does.
726
Tim Peters95b3f782001-05-14 18:39:41 +0000727- pprint functions now much faster for large containers (tuple, list, dict).
728
Tim Peters7b9542a2001-06-10 23:40:19 +0000729- New 'q' and 'Q' format codes in the struct module, corresponding to C
730 types "long long" and "unsigned long long" (on Windows, __int64). In
731 native mode, these can be used only when the platform C compiler supports
732 these types (when HAVE_LONG_LONG is #define'd by the Python config
733 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000734 In standard mode, 'q' and 'Q' are supported on all platforms, and are
735 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000736
Guido van Rossum83213cc2001-06-12 16:48:52 +0000737- The site module installs a new built-in function 'help' that invokes
738 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
739 it displays a message reminding the user to use 'help()' or
740 'help(object)'.
741
Tim Petersa814db52001-05-14 07:05:58 +0000742Tests
743
744- New test_mutants.py runs dict comparisons where the key and value
745 comparison operators mutute the dicts randomly during comparison. This
746 rapidly causes Python to crash under earlier releases (not for the faint
747 of heart: it can also cause Win9x to freeze or reboot!).
748
749- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000750 pprint.isreadable() return sensible results. Also verifies that simple
751 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000752
Tim Peters4324aa32001-05-28 22:30:08 +0000753C API
754
755- Removed the unused last_is_sticky argument from the internal
756 _PyTuple_Resize(). If this affects you, you were cheating.
757
758
Guido van Rossum55a78992001-07-17 17:22:32 +0000759======================================================================
760
761
Guido van Rossumffe13be2001-04-16 18:46:45 +0000762What's New in Python 2.1 (final)?
763=================================
764
765We only changed a few things since the last release candidate, all in
766Python library code:
767
768- A bug in the locale module was fixed that affected locales which
769 define no grouping for numeric formatting.
770
771- A few bugs in the weakref module's implementations of weak
772 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
773 and the test suite was updated to check for these bugs.
774
775- An old bug in the os.path.walk() function (introduced in Python
776 2.0!) was fixed: a non-existent file would cause an exception
777 instead of being ignored.
778
779- Fixed a few bugs in the new symtable module found by Neil Norwitz's
780 PyChecker.
781
782
Guido van Rossum5b08f132001-04-16 02:05:23 +0000783What's New in Python 2.1c2?
784===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000785
Guido van Rossum5b08f132001-04-16 02:05:23 +0000786A flurry of small changes, and one showstopper fixed in the nick of
787time made it necessary to release another release candidate. The list
788here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000789
Guido van Rossum5b08f132001-04-16 02:05:23 +0000790Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000791
Guido van Rossum5b08f132001-04-16 02:05:23 +0000792- Tim discovered a nasty bug in the dictionary code, caused by
793 PyDict_Next() calling dict_resize(), and the GC code's use of
794 PyDict_Next() violating an assumption in dict_items(). This was
795 fixed with considerable amounts of band-aid, but the net effect is a
796 saner and more robust implementation.
797
798- Made a bunch of symbols static that were accidentally global.
799
800Build and Ports
801
802- The setup.py script didn't check for a new enough version of zlib
803 (1.1.3 is needed). Now it does.
804
805- Changed "make clean" target to also remove shared libraries.
806
807- Added a more general warning about the SGI Irix optimizer to README.
808
809Library
810
811- Fix a bug in urllib.basejoin("http://host", "../file.html") which
812 omitted the slash between host and file.html.
813
814- The mailbox module's _Mailbox class contained a completely broken
815 and undocumented seek() method. Ripped it out.
816
817- Fixed a bunch of typos in various library modules (urllib2, smtpd,
818 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
819
820- Fixed a few last-minute bugs in unittest.
821
822Extensions
823
824- Reverted the patch to the OpenSSL code in socketmodule.c to support
825 RAND_status() and the EGD, and the subsequent patch that tried to
826 fix it for pre-0.9.5 versions; the problem with the patch is that on
827 some systems it issues a warning whenever socket is imported, and
828 that's unacceptable.
829
830Tests
831
832- Fixed the pickle tests to work with "import test.test_pickle".
833
834- Tweaked test_locale.py to actually run the test Windows.
835
836- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
837 not "wb" (which is not a valid mode at all).
838
839- Fix pstats browser crashes. Import readline if it exists to make
840 the user interface nicer.
841
842- Add "import thread" to the top of test modules that import the
843 threading module (test_asynchat and test_threadedtempfile). This
844 prevents test failures caused by a broken threading module resulting
845 from a previously caught failed import.
846
847- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
848 needed on some platforms (e.g. Solaris 8) when the tests are run
849 twice in succession.
850
851- Skip rather than fail test_sunaudiodev if no audio device is found.
852
853
854What's New in Python 2.1c1?
855===========================
856
857This list was significantly updated when 2.1c2 was released; the 2.1c1
858release didn't mention most changes that were actually part of 2.1c1:
859
860Legal
861
862- Copyright was assigned to the Python Software Foundation (PSF) and a
863 PSF license (very similar to the CNRI license) was added.
864
865- The CNRI copyright notice was updated to include 2001.
866
867Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000868
Guido van Rossumc9932722001-04-12 02:31:27 +0000869- After a public outcry, assignment to __debug__ is no longer illegal;
870 instead, a warning is issued. It will become illegal in 2.2.
871
Guido van Rossum5b08f132001-04-16 02:05:23 +0000872- Fixed a core dump with "%#x" % 0, and changed the semantics so that
873 "%#x" now always prepends "0x", even if the value is zero.
874
875- Fixed some nits in the bytecode compiler.
876
877- Fixed core dumps when calling certain kinds of non-functions.
878
879- Fixed various core dumps caused by reference count bugs.
880
881Build and Ports
882
883- Use INSTALL_SCRIPT to install script files.
884
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000885- New port: SCO Unixware 7, by Billy G. Allie.
886
Guido van Rossum5b08f132001-04-16 02:05:23 +0000887- Updated RISCOS port.
888
889- Updated BeOS port and notes.
890
891- Various other porting problems resolved.
892
893Library
894
895- The TERMIOS and SOCKET modules are now truly obsolete and
896 unnecessary. Their symbols are incorporated in the termios and
897 socket modules.
898
899- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
900 better tests for pickling.
901
902- threading: make Condition.wait() robust against KeyboardInterrupt.
903
904- zipfile: add support to zipfile to support opening an archive
905 represented by an open file rather than a file name. Fix bug where
906 the archive was not properly closed. Fixed a bug in this bugfix
907 where flush() was called for a read-only file.
908
909- imputil: added an uninstall() method to the ImportManager.
910
911- Canvas: fixed bugs in lower() and tkraise() methods.
912
913- SocketServer: API change (added overridable close_request() method)
914 so that the TCP server can explicitly close the request.
915
916- pstats: Eric Raymond added a simple interactive statistics browser,
917 invoked when the module is run as a script.
918
919- locale: fixed a problem in format().
920
921- webbrowser: made it work when the BROWSER environment variable has a
922 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
923 KDE 2. Fixed some other nits.
924
925- unittest: changes to allow using a different exception than
926 AssertionError, and added a few more function aliases. Some other
927 small changes.
928
929- urllib, urllib2: fixed redirect problems and a coupleof other nits.
930
931- asynchat: fixed a critical bug in asynchat that slipped through the
932 2.1b2 release. Fixed another rare bug.
933
934- Fix some unqualified except: clauses (always a bad code example).
935
936XML
937
938- pyexpat: new API get_version_string().
939
940- Fixed some minidom bugs.
941
942Extensions
943
944- Fixed a core dump in _weakref. Removed the weakref.mapping()
945 function (it adds nothing to the API).
946
947- Rationalized the use of header files in the readline module, to make
948 it compile (albeit with some warnings) with the very recent readline
949 4.2, without breaking for earlier versions.
950
951- Hopefully fixed a buffering problem in linuxaudiodev.
952
953- Attempted a fix to make the OpenSSL support in the socket module
954 work again with pre-0.9.5 versions of OpenSSL.
955
956Tests
957
958- Added a test case for asynchat and asyncore.
959
960- Removed coupling between tests where one test failing could break
961 another.
962
963Tools
964
965- Ping added an interactive help browser to pydoc, fixed some nits
966 in the rest of the pydoc code, and added some features to his
967 inspect module.
968
969- An updated python-mode.el version 4.1 which integrates Ken
970 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
971 much nicer in XEmacs and Emacs. When stepping through your program
972 with pdb, in either the shell window or the *Python* window, the
973 source file and line will be tracked by an arrow. Very cool!
974
975- IDLE: syntax warnings in interactive mode are changed into errors.
976
977- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +0000978 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +0000979
980- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000981
Barry Warsaw11e89c72001-04-11 20:37:57 +0000982
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000983What's New in Python 2.1 beta 2?
984================================
985
Guido van Rossum053ae352001-03-22 14:17:21 +0000986(Unlisted are many fixed bugs, more documentation, etc.)
987
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000988Core language, builtins, and interpreter
989
Guido van Rossum053ae352001-03-22 14:17:21 +0000990- The nested scopes work (enabled by "from __future__ import
991 nested_scopes") is completed; in particular, the future now extends
992 into code executed through exec, eval() and execfile(), and into the
993 interactive interpreter.
994
995- When calling a base class method (e.g. BaseClass.__init__(self)),
996 this is now allowed even if self is not strictly spoken a class
997 instance (e.g. when using metaclasses or the Don Beaudry hook).
998
999- Slice objects are now comparable but not hashable; this prevents
1000 dict[:] from being accepted but meaningless.
1001
1002- Complex division is now calculated using less braindead algorithms.
1003 This doesn't change semantics except it's more likely to give useful
1004 results in extreme cases. Complex repr() now uses full precision
1005 like float repr().
1006
1007- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1008
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001009- It is illegal to assign to the name __debug__, which is set when the
1010 interpreter starts. It is effectively a compile-time constant.
1011
1012- A warning will be issued if a global statement for a variable
1013 follows a use or assignment of that variable.
1014
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001015Standard library
1016
Guido van Rossum053ae352001-03-22 14:17:21 +00001017- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1018 inspired by JUnit), is now part of the standard library. You now
1019 have a choice of two testing frameworks: unittest requires you to
1020 write testcases as separate code, doctest gathers them from
1021 docstrings. Both approaches have their advantages and
1022 disadvantages.
1023
1024- A new module Tix was added, which wraps the Tix extension library
1025 for Tk. With that module, it is not necessary to statically link
1026 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1027 require" command. See Demo/tix/.
1028
1029- tzparse.py is now obsolete.
1030
1031- In gzip.py, the seek() and tell() methods are removed -- they were
1032 non-functional anyway, and it's better if callers can test for their
1033 existence with hasattr().
1034
1035Python/C API
1036
1037- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1038 that's already in the dictionary during a PyDict_Next() iteration.
1039 This used to fail occasionally when a dictionary resize operation
1040 could be triggered that would rehash all the keys. All other
1041 modifications to the dictionary are still off-limits during a
1042 PyDict_Next() iteration!
1043
1044- New extended APIs related to passing compiler variables around.
1045
1046- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1047 implement isinstance() and issubclass().
1048
1049- Py_BuildValue() now has a "D" conversion to create a Python complex
1050 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001051
Fred Drake4e262a92001-03-22 18:26:47 +00001052- Extensions types which support weak references must now set the
1053 field allocated for the weak reference machinery to NULL themselves;
1054 this is done to avoid the cost of checking each object for having a
1055 weakly referencable type in PyObject_INIT(), since most types are
1056 not weakly referencable.
1057
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001058- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1059 free variables and cell variables to and from the frame's f_locals.
1060
1061- Variants of several functions defined in pythonrun.h have been added
1062 to support the nested_scopes future statement. The variants all end
1063 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1064 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1065 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001066 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001067
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001068Distutils
1069
1070- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1071 into the release tree.
1072
Tim Peters0e57abf2001-05-02 07:39:38 +00001073- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001074 (an uninstaller, more customization of the installer's display)
1075
1076- from Jack Jansen: added Mac-specific code to generate a dialog for
1077 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001078 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001079 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001080
1081- added 'platforms' and 'keywords' to the set of metadata that can be
1082 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001083
1084- applied patches from Jason Tishler to make the compiler class work with
1085 Cygwin.
1086
1087
Tim Peters2fe289a2001-03-01 22:19:38 +00001088What's New in Python 2.1 beta 1?
1089================================
Tim Petersd66595f2001-02-04 03:09:53 +00001090
1091Core language, builtins, and interpreter
1092
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001093- Following an outcry from the community about the amount of code
1094 broken by the nested scopes feature introduced in 2.1a2, we decided
1095 to make this feature optional, and to wait until Python 2.2 (or at
1096 least 6 months) to make it standard. The option can be enabled on a
1097 per-module basis by adding "from __future__ import nested_scopes" at
1098 the beginning of a module (before any other statements, but after
1099 comments and an optional docstring). See PEP 236 (Back to the
1100 __future__) for a description of the __future__ statement. PEP 227
1101 (Statically Nested Scopes) has been updated to reflect this change,
1102 and to clarify the semantics in a number of endcases.
1103
1104- The nested scopes code, when enabled, has been hardened, and most
1105 bugs and memory leaks in it have been fixed.
1106
1107- Compile-time warnings are now generated for a number of conditions
1108 that will break or change in meaning when nested scopes are enabled:
1109
1110 - Using "from...import *" or "exec" without in-clause in a function
1111 scope that also defines a lambda or nested function with one or
1112 more free (non-local) variables. The presence of the import* or
1113 bare exec makes it impossible for the compiler to determine the
1114 exact set of local variables in the outer scope, which makes it
1115 impossible to determine the bindings for free variables in the
1116 inner scope. To avoid the warning about import *, change it into
1117 an import of explicitly name object, or move the import* statement
1118 to the global scope; to avoid the warning about bare exec, use
1119 exec...in... (a good idea anyway -- there's a possibility that
1120 bare exec will be deprecated in the future).
1121
1122 - Use of a global variable in a nested scope with the same name as a
1123 local variable in a surrounding scope. This will change in
1124 meaning with nested scopes: the name in the inner scope will
1125 reference the variable in the outer scope rather than the global
1126 of the same name. To avoid the warning, either rename the outer
1127 variable, or use a global statement in the inner function.
1128
Neil Schemenauera35c6882001-02-27 04:45:05 +00001129- An optional object allocator has been included. This allocator is
1130 optimized for Python objects and should be faster and use less memory
1131 than the standard system allocator. It is not enabled by default
1132 because of possible thread safety problems. The allocator is only
1133 protected by the Python interpreter lock and it is possible that some
1134 extension modules require a thread safe allocator. The object
1135 allocator can be enabled by providing the "--with-pymalloc" option to
1136 configure.
1137
Tim Petersd66595f2001-02-04 03:09:53 +00001138Standard library
1139
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001140- pyexpat now detects the expat version if expat.h defines it. A
1141 number of additional handlers are provided, which are only available
1142 since expat 1.95. In addition, the methods SetParamEntityParsing and
1143 GetInputContext of Parser objects are available with 1.95.x
1144 only. Parser objects now provide the ordered_attributes and
1145 specified_attributes attributes. A new module expat.model was added,
1146 which offers a number of additional constants if 1.95.x is used.
1147
1148- xml.dom offers the new functions registerDOMImplementation and
1149 getDOMImplementation.
1150
1151- xml.dom.minidom offers a toprettyxml method. A number of DOM
1152 conformance issues have been resolved. In particular, Element now
1153 has an hasAttributes method, and the handling of namespaces was
1154 improved.
1155
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001156- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1157 getting information about live Python code, and pydoc.py, a module
1158 for interactively converting docstrings to HTML or text.
1159 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001160 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001161 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1162 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001163
Tim Peters1eff7962001-03-01 02:31:33 +00001164- New library module difflib.py, primarily packaging the SequenceMatcher
1165 class at the heart of the popular ndiff.py file-comparison tool.
1166
1167- doctest.py (a framework for verifying Python code examples in docstrings)
1168 is now part of the std library.
1169
Tim Petersd66595f2001-02-04 03:09:53 +00001170Windows changes
1171
Guido van Rossume3955a82001-03-02 14:05:59 +00001172- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1173 small GUI that lets you browse the module docstrings using your
1174 default web browser.
1175
Tim Peters1eff7962001-03-01 02:31:33 +00001176- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1177 Platforms) is implemented. See
1178
1179 http://python.sourceforge.net/peps/pep-0235.html
1180
1181 for full details, especially the "Current Lower-Left Semantics" section.
1182 The new Windows import rules are simpler than before:
1183
1184 A. If the PYTHONCASEOK environment variable exists, same as
1185 before: silently accept the first case-insensitive match of any
1186 kind; raise ImportError if none found.
1187
1188 B. Else search sys.path for the first case-sensitive match; raise
1189 ImportError if none found.
1190
1191 The same rules have been implented on other platforms with case-
1192 insensitive but case-preserving filesystems too (including Cygwin, and
1193 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001194
Tim Peters25a9ce32001-02-19 07:06:36 +00001195- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1196 what it's supposed to do (and does do under NT and 2000) via direct
1197 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001198 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001199 all Win9x systems before.
1200
Tim Peters1eff7962001-03-01 02:31:33 +00001201- Build: Subproject _test (effectively) renamed to _testcapi.
1202
Tim Peters2fe289a2001-03-01 22:19:38 +00001203New platforms
1204
1205- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1206 Thanks to Steven Majewski!
1207
1208- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1209 Tishler!
1210
Guido van Rossum9089b272001-03-02 06:49:50 +00001211- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1212 Schwertberger! See RISCOS/README for more information -- it seems
1213 that because of the bizarre filename conventions on RISCOS, no port
1214 to that platform is easy. Note that the new variable os.endsep is
1215 silently supported in order to make life easier on this platform,
1216 but we don't advertise it because it's not worth for most folks to
1217 care about RISCOS portability.
1218
Tim Peters25a9ce32001-02-19 07:06:36 +00001219
Tim Petersd7b5e882001-01-25 03:36:26 +00001220What's New in Python 2.1 alpha 2?
1221=================================
Tim Peters40ead762001-01-27 05:35:26 +00001222
Tim Petersd7b5e882001-01-25 03:36:26 +00001223Core language, builtins, and interpreter
1224
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001225- Scopes nest. If a name is used in a function or class, but is not
1226 local, the definition in the nearest enclosing function scope will
1227 be used. One consequence of this change is that lambda statements
1228 could reference variables in the namespaces where the lambda is
1229 defined. In some unusual cases, this change will break code.
1230
1231 In all previous version of Python, names were resolved in exactly
1232 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001233 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001234 function A is defined within a function B, the names bound in B are
1235 not visible in A. The new rules make names bound in B visible in A,
1236 unless A contains a name binding that hides the binding in B.
1237
1238 Section 4.1 of the reference manual describes the new scoping rules
1239 in detail. The test script in Lib/test/test_scope.py demonstrates
1240 some of the effects of the change.
1241
1242 The new rules will cause existing code to break if it defines nested
1243 functions where an outer function has local variables with the same
1244 name as globals or builtins used by the inner function. Example:
1245
1246 def munge(str):
1247 def helper(x):
1248 return str(x)
1249 if type(str) != type(''):
1250 str = helper(str)
1251 return str.strip()
1252
1253 Under the old rules, the name str in helper() is bound to the
1254 builtin function str(). Under the new rules, it will be bound to
1255 the argument named str and an error will occur when helper() is
1256 called.
1257
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001258- The compiler will report a SyntaxError if "from ... import *" occurs
1259 in a function or class scope. The language reference has documented
1260 that this case is illegal, but the compiler never checked for it.
1261 The recent introduction of nested scope makes the meaning of this
1262 form of name binding ambiguous. In a future release, the compiler
1263 may allow this form when there is no possibility of ambiguity.
1264
Tim Peters40ead762001-01-27 05:35:26 +00001265- repr(string) is easier to read, now using hex escapes instead of octal,
1266 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1267
1268 >>> "\texample \r\n" + chr(0) + chr(255)
1269 '\texample \r\n\x00\xff' # in 2.1
1270 '\011example \015\012\000\377' # in 2.0
1271
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001272- Functions are now compared and hashed by identity, not by value, since
1273 the func_code attribute is writable.
1274
Fred Drakefb9d7122001-02-01 20:00:40 +00001275- Weak references (PEP 205) have been added. This involves a few
1276 changes in the core, an extension module (_weakref), and a Python
1277 module (weakref). The weakref module is the public interface. It
1278 includes support for "explicit" weak references, proxy objects, and
1279 mappings with weakly held values.
1280
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001281- A 'continue' statement can now appear in a try block within the body
1282 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001283 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001284
Tim Petersd7b5e882001-01-25 03:36:26 +00001285Standard library
1286
Barry Warsaw30dbd142001-01-31 22:14:01 +00001287- mailbox.py now has a new class, PortableUnixMailbox which is
1288 identical to UnixMailbox but uses a more portable scheme for
1289 determining From_ separators. Also, the constructors for all the
1290 classes in this module have a new optional `factory' argument, which
1291 is a callable used when new message classes must be instantiated by
1292 the next() method.
1293
Tim Petersd7b5e882001-01-25 03:36:26 +00001294- random.py is now self-contained, and offers all the functionality of
1295 the now-deprecated whrandom.py. See the docs for details. random.py
1296 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001297 and restoring the internal state of the generator; and jumpahead(n),
1298 for quickly forcing the internal state to be the same as if n calls to
1299 random() had been made. The latter is particularly useful for multi-
1300 threaded programs, creating one instance of the random.Random() class for
1301 each thread, then using .jumpahead() to force each instance to use a
1302 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001303
Tim Peters0de88fc2001-02-01 04:59:18 +00001304- random.py's seed() function is new. For bit-for-bit compatibility with
1305 prior releases, use the whseed function instead. The new seed function
1306 addresses two problems: (1) The old function couldn't produce more than
1307 about 2**24 distinct internal states; the new one about 2**45 (the best
1308 that can be done in the Wichmann-Hill generator). (2) The old function
1309 sometimes produced identical internal states when passed distinct
1310 integers, and there was no simple way to predict when that would happen;
1311 the new one guarantees to produce distinct internal states for all
1312 arguments in [0, 27814431486576L).
1313
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001314- The socket module now supports raw packets on Linux. The socket
1315 family is AF_PACKET.
1316
Tim Peters9ea17ac2001-02-02 05:57:15 +00001317- test_capi.py is a start at running tests of the Python C API. The tests
1318 are implemented by the new Modules/_testmodule.c.
1319
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001320- A new extension module, _symtable, provides provisional access to the
1321 internal symbol table used by the Python compiler. A higher-level
1322 interface will be added on top of _symtable in a future release.
1323
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001324- Removed the obsolete soundex module.
1325
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001326- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1327 the isSameNode method; NamedNodeMap the get method.
1328
1329- xml.sax.expatreader supports the lexical handler property; it
1330 generates comment, startCDATA, and endCDATA events.
1331
Tim Petersee826f82001-01-31 19:39:44 +00001332Windows changes
1333
1334- Build procedure: the zlib project is built in a different way that
1335 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001336 the zlib binary used. See PCbuild\readme.txt for details. Your old
1337 zlib-related directories can be deleted; you'll need to download fresh
1338 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001339
Tim Peters9ea17ac2001-02-02 05:57:15 +00001340- Build: New subproject _test for the benefit of test_capi.py (see above).
1341
Tim Petersb16c56f2001-02-02 21:24:51 +00001342- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1343 interface to some Python compiler internals).
1344
1345- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001346 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001347
Tim Petersa3a3a032000-11-30 05:22:44 +00001348What's New in Python 2.1 alpha 1?
1349=================================
1350
1351Core language, builtins, and interpreter
1352
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001353- There is a new Unicode companion to the PyObject_Str() API
1354 called PyObject_Unicode(). It behaves in the same way as the
1355 former, but assures that the returned value is an Unicode object
1356 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001357
Guido van Rossumf98eda02001-01-17 15:54:45 +00001358- The comparison operators support "rich comparison overloading" (PEP
1359 207). C extension types can provide a rich comparison function in
1360 the new tp_richcompare slot in the type object. The cmp() function
1361 and the C function PyObject_Compare() first try the new rich
1362 comparison operators before trying the old 3-way comparison. There
1363 is also a new C API PyObject_RichCompare() (which also falls back on
1364 the old 3-way comparison, but does not constrain the outcome of the
1365 rich comparison to a Boolean result).
1366
1367 The rich comparison function takes two objects (at least one of
1368 which is guaranteed to have the type that provided the function) and
1369 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1370 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1371 object, which may be NotImplemented (in which case the tp_compare
1372 slot function is used as a fallback, if defined).
1373
1374 Classes can overload individual comparison operators by defining one
1375 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001376 __ge__. There are no explicit "reflected argument" versions of
1377 these; instead, __lt__ and __gt__ are each other's reflection,
1378 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1379 reflection (similar at the C level). No other implications are
1380 made; in particular, Python does not assume that == is the Boolean
1381 inverse of !=, or that < is the Boolean inverse of >=. This makes
1382 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001383
1384 Classes or types that want to implement (in)equality tests but not
1385 the ordering operators (i.e. unordered types) should implement ==
1386 and !=, and raise an error for the ordering operators.
1387
Guido van Rossuma88479f2001-01-18 14:28:08 +00001388 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001389 Boolean; e.g. a matrix type might want to return a matrix of bits
1390 for A < B, giving elementwise comparisons. Such types should ensure
1391 that any interpretation of their value in a Boolean context raises
1392 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1393 at the C level) to always raise an exception.
1394
Guido van Rossuma88479f2001-01-18 14:28:08 +00001395- Complex numbers use rich comparisons to define == and != but raise
1396 an exception for <, <=, > and >=. Unfortunately, this also means
1397 that cmp() of two complex numbers raises an exception when the two
1398 numbers differ. Since it is not mathematically meaningful to compare
1399 complex numbers except for equality, I hope that this doesn't break
1400 too much code.
1401
Tim Peters3389f192001-02-18 08:48:49 +00001402- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001403 not defined by the language, other than that it's arbitrary but
1404 consistent (see the Reference Manual). An implementation detail changed
1405 in 2.1a1 such that None now compares less than any other object. Code
1406 relying on this new behavior (like code that relied on the previous
1407 behavior) does so at its own risk.
1408
Barry Warsaw573b5412001-01-15 20:43:18 +00001409- Functions and methods now support getting and setting arbitrarily
1410 named attributes (PEP 232). Functions have a new __dict__
1411 (a.k.a. func_dict) which hold the function attributes. Methods get
1412 and set attributes on their underlying im_func. It is a TypeError
1413 to set an attribute on a bound method.
1414
Guido van Rossum051e3352001-01-15 19:11:10 +00001415- The xrange() object implementation has been improved so that
1416 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1417 limitation that in this case len(xrange(sys.maxint)) can't be
1418 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1419 work fine as long as the index i doesn't actually reach 2**31.
1420 (Python uses regular ints for sequence and string indices; fixing
1421 that is much more work.)
1422
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001423- Two changes to from...import:
1424
Guido van Rossumba381232001-02-03 15:06:40 +00001425 1) "from M import X" now works even if (after loading module M)
1426 sys.modules['M'] is not a real module; it's basically a getattr()
1427 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001428
1429 2) "from M import *" now looks for M.__all__ to decide which names to
1430 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1431 filters out names starting with '_' as before. Whether or not
1432 __all__ exists, there's no restriction on the type of M.
1433
Guido van Rossumf61f1662001-01-10 20:13:55 +00001434- File objects have a new method, xreadlines(). This is the fastest
1435 way to iterate over all lines in a file:
1436
1437 for line in file.xreadlines():
1438 ...do something to line...
1439
1440 See the xreadlines module (mentioned below) for how to do this for
1441 other file-like objects.
1442
1443- Even if you don't use file.xreadlines(), you may expect a speedup on
1444 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001445 quite a bit in platform-specific ways: on systems (like Linux) that
1446 support flockfile(), getc_unlocked(), and funlockfile(), those are
1447 used by default. On systems (like Windows) without getc_unlocked(),
1448 a complicated (but still thread-safe) method using fgets() is used by
1449 default.
1450
Tim Petersd52269b2001-01-25 06:23:18 +00001451 You can force use of the fgets() method by #define'ing
1452 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001453 getc_unlocked()).
1454
Tim Petersd52269b2001-01-25 06:23:18 +00001455 You can force fgets() not to be used by #define'ing
1456 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001457 test_bufio.py fails -- and let us know if it does!).
1458
1459- In addition, the fileinput module, while still slower than the other
1460 methods on most platforms, has been sped up too, by using
1461 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001462
1463- Support for run-time warnings has been added, including a new
1464 command line option (-W) to specify the disposition of warnings.
1465 See the description of the warnings module below.
1466
1467- Extensive changes have been made to the coercion code. This mostly
1468 affects extension modules (which can now implement mixed-type
1469 numerical operators without having to use coercion), but
1470 occasionally, in boundary cases the coercion semantics have changed
1471 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001472 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001473 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001474 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001475
Guido van Rossumf98eda02001-01-17 15:54:45 +00001476- In connection with the coercion changes, a new built-in singleton
1477 object, NotImplemented is defined. This can be returned for
1478 operations that wish to indicate they are not implemented for a
1479 particular combination of arguments. From C, this is
1480 Py_NotImplemented.
1481
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001482- The interpreter accepts now bytecode files on the command line even
1483 if they do not have a .pyc or .pyo extension. On Linux, after executing
1484
Martin v. Löwise214baa2001-02-04 22:37:56 +00001485import imp,sys,string
1486magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1487reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1488open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001489
1490 any byte code file can be used as an executable (i.e. as an argument
1491 to execve(2)).
1492
Tim Peters9940b802000-12-01 07:59:35 +00001493- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001494 character. In 1.6 and earlier, they never produced a sign,
1495 and raised an error if the value of the long was too large
1496 to fit in a Python int. In 2.0, they produced a sign if and
1497 only if too large to fit in an int. This was inconsistent
1498 across platforms (because the size of an int varies across
1499 platforms), and inconsistent with hex() and oct(). Example:
1500
1501 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001502 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001503 'ffffffbe' # in 2.0 and before, on 32-bit machines
1504 >>> hex(-0x42L)
1505 '-0x42L' # in all versions of Python
1506
Tim Peters9940b802000-12-01 07:59:35 +00001507 The behavior of %d formats for negative Python longs remains
1508 the same as in 2.0 (although in 1.6 and before, they raised
1509 an error if the long didn't fit in a Python int).
1510
1511 %u formats don't make sense for Python longs, but are allowed
1512 and treated the same as %d in 2.1. In 2.0, a negative long
1513 formatted via %u produced a sign if and only if too large to
1514 fit in an int. In 1.6 and earlier, a negative long formatted
1515 via %u raised an error if it was too big to fit in an int.
1516
Guido van Rossum3661d392000-12-12 22:10:31 +00001517- Dictionary objects have an odd new method, popitem(). This removes
1518 an arbitrary item from the dictionary and returns it (in the form of
1519 a (key, value) pair). This can be useful for algorithms that use a
1520 dictionary as a bag of "to do" items and repeatedly need to pick one
1521 item. Such algorithms normally end up running in quadratic time;
1522 using popitem() they can usually be made to run in linear time.
1523
Tim Peters36cdad12000-12-29 02:06:45 +00001524Standard library
1525
Thomas Woutersfe385252001-01-19 23:16:56 +00001526- In the time module, the time argument to the functions strftime,
1527 localtime, gmtime, asctime and ctime is now optional, defaulting to
1528 the current time (in the local timezone).
1529
Guido van Rossumda91f222001-01-15 16:36:08 +00001530- The ftplib module now defaults to passive mode, which is deemed a
1531 more useful default given that clients are often inside firewalls
1532 these days. Note that this could break if ftplib is used to connect
1533 to a *server* that is inside a firewall, from outside; this is
1534 expected to be a very rare situation. To fix that, you can call
1535 ftp.set_pasv(0).
1536
Martin v. Löwis10a27872001-01-13 09:54:41 +00001537- The module site now treats .pth files not only for path configuration,
1538 but also supports extensions to the initialization code: Lines starting
1539 with import are executed.
1540
Guido van Rossumf61f1662001-01-10 20:13:55 +00001541- There's a new module, warnings, which implements a mechanism for
1542 issuing and filtering warnings. There are some new built-in
1543 exceptions that serve as warning categories, and a new command line
1544 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1545 turns warnings into errors). warnings.warn(message[, category])
1546 issues a warning message; this can also be called from C as
1547 PyErr_Warn(category, message).
1548
1549- A new module xreadlines was added. This exports a single factory
1550 function, xreadlines(). The intention is that this code is the
1551 absolutely fastest way to iterate over all lines in an open
1552 file(-like) object:
1553
1554 import xreadlines
1555 for line in xreadlines.xreadlines(file):
1556 ...do something to line...
1557
1558 This is equivalent to the previous the speed record holder using
1559 file.readlines(sizehint). Note that if file is a real file object
1560 (as opposed to a file-like object), this is equivalent:
1561
1562 for line in file.xreadlines():
1563 ...do something to line...
1564
Tim Peters36cdad12000-12-29 02:06:45 +00001565- The bisect module has new functions bisect_left, insort_left,
1566 bisect_right and insort_right. The old names bisect and insort
1567 are now aliases for bisect_right and insort_right. XXX_right
1568 and XXX_left methods differ in what happens when the new element
1569 compares equal to one or more elements already in the list: the
1570 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001571 right. Code that doesn't care where equal elements end up should
1572 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001573
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001574- The new curses.panel module wraps the panel library that forms part
1575 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1576
Guido van Rossumf61f1662001-01-10 20:13:55 +00001577- The SocketServer module now sets the allow_reuse_address flag by
1578 default in the TCPServer class.
1579
1580- A new function, sys._getframe(), returns the stack frame pointer of
1581 the caller. This is intended only as a building block for
1582 higher-level mechanisms such as string interpolation.
1583
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001584- The pyexpat module supports a number of new handlers, which are
1585 available only in expat 1.2. If invocation of a callback fails, it
1586 will report an additional frame in the traceback. Parser objects
1587 participate now in garbage collection. If expat reports an unknown
1588 encoding, pyexpat will try to use a Python codec; that works only
1589 for single-byte charsets. The parser type objects is exposed as
1590 XMLParserObject.
1591
1592- xml.dom now offers standard definitions for symbolic node type and
1593 exception code constants, and a hierarchy of DOM exceptions. minidom
1594 was adjusted to use them.
1595
1596- The conformance of xml.dom.minidom to the DOM specification was
1597 improved. It detects a number of additional error cases; the
1598 previous/next relationship works even when the tree is modified;
1599 Node supports the normalize() method; NamedNodeMap, DocumentType and
1600 DOMImplementation classes were added; Element supports the
1601 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1602 method.
1603
Guido van Rossumf61f1662001-01-10 20:13:55 +00001604Build issues
1605
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001606- For Unix (and Unix-compatible) builds, configuration and building of
1607 extension modules is now greatly automated. Rather than having to
1608 edit the Modules/Setup file to indicate which modules should be
1609 built and where their include files and libraries are, a
1610 distutils-based setup.py script now takes care of building most
1611 extension modules. All extension modules built this way are built
1612 as shared libraries. Only a few modules that must be linked
1613 statically are still listed in the Setup file; you won't need to
1614 edit their configuration.
1615
1616- Python should now build out of the box on Cygwin. If it doesn't,
1617 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001618
1619- Python now always uses its own (renamed) implementation of getopt()
1620 -- there's too much variation among C library getopt()
1621 implementations.
1622
1623- C++ compilers are better supported; the CXX macro is always set to a
1624 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001625
Tim Petersd92dfe02000-12-12 01:18:41 +00001626Windows changes
1627
1628- select module: By default under Windows, a select() call
1629 can specify no more than 64 sockets. Python now boosts
1630 this Microsoft default to 512. If you need even more than
1631 that, see the MS docs (you'll need to #define FD_SETSIZE
1632 and recompile Python from source).
1633
Guido van Rossumf61f1662001-01-10 20:13:55 +00001634- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1635 subdirectory is no more!
1636
Tim Petersa3a3a032000-11-30 05:22:44 +00001637
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001638What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001639=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001640
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001641Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001642changes are in the file HISTORY. If you are making the jump directly
1643from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1644HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001645
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001646Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1647the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1648http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001649
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001650--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001651
1652======================================================================
1653
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001654What's new in 2.0 (since release candidate 1)?
1655==============================================
1656
1657Standard library
1658
1659- The copy_reg module was modified to clarify its intended use: to
1660 register pickle support for extension types, not for classes.
1661 pickle() will raise a TypeError if it is passed a class.
1662
1663- Fixed a bug in gettext's "normalize and expand" code that prevented
1664 it from finding an existing .mo file.
1665
1666- Restored support for HTTP/0.9 servers in httplib.
1667
Tim Peters989b7b92000-10-16 20:24:53 +00001668- The math module was changed to stop raising OverflowError in case of
1669 underflow, and return 0 instead in underflow cases. Whether Python
1670 used to raise OverflowError in case of underflow was platform-
1671 dependent (it did when the platform math library set errno to ERANGE
1672 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001673
1674- Fixed a bug in StringIO that occurred when the file position was not
1675 at the end of the file and write() was called with enough data to
1676 extend past the end of the file.
1677
1678- Fixed a bug that caused Tkinter error messages to get lost on
1679 Windows. The bug was fixed by replacing direct use of
1680 interp->result with Tcl_GetStringResult(interp).
1681
1682- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1683 redirect response.
1684
1685- Several changes were made to distutils: Some debugging code was
1686 removed from util. Fixed the installer used when an external zip
1687 program (like WinZip) is not found; the source code for this
1688 installer is in Misc/distutils. check_lib() was modified to behave
1689 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1690 test for whether installed modules are on sys.path was changed to
1691 use both normcase() and normpath().
1692
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001693- Several minor bugs were fixed in the xml package (the minidom,
1694 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001695
1696- The regression test driver (regrtest.py) behavior when invoked with
1697 -l changed: It now reports a count of objects that are recognized as
1698 garbage but not freed by the garbage collector.
1699
Tim Peters989b7b92000-10-16 20:24:53 +00001700- The regression test for the math module was changed to test
1701 exceptional behavior when the test is run in verbose mode. Python
1702 cannot yet guarantee consistent exception behavior across platforms,
1703 so the exception part of test_math is run only in verbose mode, and
1704 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001705
1706Internals
1707
1708- PyOS_CheckStack() has been disabled on Win64, where it caused
1709 test_sre to fail.
1710
1711Build issues
1712
1713- Changed compiler flags, so that gcc is always invoked with -Wall and
1714 -Wstrict-prototypes. Users compiling Python with GCC should see
1715 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001716 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001717 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001718
Tim Petersa3a3a032000-11-30 05:22:44 +00001719- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001720
1721Tools and other miscellany
1722
1723- The compiler in Tools/compiler was updated to support the new
1724 language features introduced in 2.0: extended print statement, list
1725 comprehensions, and augmented assignments. The new compiler should
1726 also be backwards compatible with Python 1.5.2; the compiler will
1727 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001728 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001729
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001730What's new in 2.0 release candidate 1 (since beta 2)?
1731=====================================================
1732
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001733What is release candidate 1?
1734
1735We believe that release candidate 1 will fix all known bugs that we
1736intend to fix for the 2.0 final release. This release should be a bit
1737more stable than the previous betas. We would like to see even more
1738widespread testing before the final release, so we are producing this
1739release candidate. The final release will be exactly the same unless
1740any show-stopping (or brown bag) bugs are found by testers of the
1741release candidate.
1742
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001743All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001744to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001745
1746Core language, builtins, and interpreter
1747
1748- A bug that caused crashes when __coerce__ was used with augmented
1749 assignment, e.g. +=, was fixed.
1750
1751- Raise ZeroDivisionError when raising zero to a negative number,
1752 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1753 power operator and the result of math.pow(0.0, -2.0) will vary by
1754 platform. On Linux, it raises a ValueError.
1755
1756- A bug in Unicode string interpolation was fixed that occasionally
1757 caused errors with formats including "%%". For example, the
1758 following expression "%% %s" % u"abc" no longer raises a TypeError.
1759
1760- Compilation of deeply nested expressions raises MemoryError instead
1761 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1762
1763- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1764 rendering them useless. They are now written in binary mode again.
1765
1766Standard library
1767
1768- Keyword arguments are now accepted for most pattern and match object
1769 methods in SRE, the standard regular expression engine.
1770
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001771- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001772 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001773
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001774- Several bugs in the Unicode handling and error handling in _tkinter
1775 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001776
1777- Fix memory management errors in Merge() and Tkapp_Call() routines.
1778
1779- Several changes were made to cStringIO to make it compatible with
1780 the file-like object interface and with StringIO. If operations are
1781 performed on a closed object, an exception is raised. The truncate
1782 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001783 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001784
1785- There were many changes made to the linuxaudiodev module and its
1786 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001787 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001788
1789 Note that this module is named poorly, because it should work
1790 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001791 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001792
1793 The module now raises exceptions when errors occur instead of
1794 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1795 audio) and defines a getptr() method that calls the
1796 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1797
1798- The library_version attribute, introduced in an earlier beta, was
1799 removed because it can not be supported with early versions of the C
1800 readline library, which provides no way to determine the version at
1801 compile-time.
1802
1803- The binascii module is now enabled on Win64.
1804
Tim Peters46446d62000-10-09 21:19:31 +00001805- tokenize.py no longer suffers "recursion depth" errors when parsing
1806 programs with very long string literals.
1807
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001808Internals
1809
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001810- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001811 which is called when the interpreter starts up to determine where
1812 the standard library is installed. These vulnerabilities affect all
1813 previous versions of Python and can be exploited by setting very
1814 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1815 setuid Python script, although use of the wrapper in
1816 Misc/setuid-prog.c will eliminate the vulnerability.
1817
1818- Fixed garbage collection bugs in instance creation that were
1819 triggered when errors occurred during initialization. The solution,
1820 applied in cPickle and in PyInstance_New(), is to call
1821 PyObject_GC_Init() after the initialization of the object's
1822 container attributes is complete.
1823
1824- pyexpat adds definitions of PyModule_AddStringConstant and
1825 PyModule_AddObject if the Python version is less than 2.0, which
1826 provides compatibility with PyXML on Python 1.5.2.
1827
1828- If the platform has a bogus definition for LONG_BIT (the number of
1829 bits in a long), an error will be reported at compile time.
1830
1831- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1832 collection crashes and possibly other, unreported crashes.
1833
1834- Fixed a memory leak in _PyUnicode_Fini().
1835
1836Build issues
1837
1838- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001839 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001840 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001841
1842- The mmap.PAGESIZE constant is now initialized using sysconf when
1843 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1844
1845- The md5 file should now compile on all platforms.
1846
1847- The select module now compiles on platforms that do not define
1848 POLLRDNORM and related constants.
1849
1850- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001851 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001852
Jeremy Hylton10921202000-10-09 18:34:12 +00001853- BeOS: A number of changes were made to the build and installation
1854 process. ar-fake now operates on a directory of object files.
1855 dl_export.h is gone, and its macros now appear on the mwcc command
1856 line during build on PPC BeOS.
1857
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001858- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001859 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001860
1861- Cygwin: Support for shared libraries, Tkinter, and sockets.
1862
1863- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1864
1865Tools and other miscellany
1866
1867- Removed debugging prints from main used with freeze.
1868
Tim Peters46446d62000-10-09 21:19:31 +00001869- IDLE auto-indent no longer crashes when it encounters Unicode
1870 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001871
1872What's new in 2.0 beta 2 (since beta 1)?
1873========================================
1874
1875Core language, builtins, and interpreter
1876
Tim Peters482c0212000-09-26 06:33:09 +00001877- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001878 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001879
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001880- Add -h and -V command line options to print the usage message and
1881 Python version number and exit immediately.
1882
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001883- eval() and exec accept Unicode objects as code parameters.
1884
1885- getattr() and setattr() now also accept Unicode objects for the
1886 attribute name, which are converted to strings using the default
1887 encoding before lookup.
1888
1889- Multiplication on string and Unicode now does proper bounds
1890 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1891 string is too long."
1892
1893- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001894 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001895
Jeremy Hylton1b618592000-09-26 05:32:36 +00001896
1897Standard library and extensions
1898
Guido van Rossum5b08f132001-04-16 02:05:23 +00001899- socket module: the OpenSSL code now adds support for RAND_status()
1900 and EGD (Entropy Gathering Device).
1901
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001902- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001903 argument checking; it still takes no arguments.
1904
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001905- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001906
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001907- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001908
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001909- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001910
1911- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001912 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001913
1914- copy: Copy Unicode objects atomically.
1915
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001916- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001917
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001918- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001919
Fred Drake67233bc2000-09-26 16:40:27 +00001920- dbm: Add get() and setdefault() methods to dbm object. Add constant
1921 `library' to module that names the library used. Added doc strings
1922 and method names to error messages. Uses configure to determine
1923 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
1924 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001925
1926- distutils: Update to version 0.9.3.
1927
1928- dl: Add several dl.RTLD_ constants.
1929
1930- fpectl: Now supported on FreeBSD.
1931
1932- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
1933 found by the collector will be saved in gc.garbage. This is useful
1934 for debugging a program that creates reference cycles.
1935
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001936- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00001937 of HTTP class. Do not close socket on zero-length response. Do not
1938 crash when server sends invalid content-length header.
1939
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001940- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001941
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001942- marshal: When reading a short, sign-extend on platforms where shorts
1943 are bigger than 16 bits. When reading a long, repair the unportable
1944 sign extension that was being done for 64-bit machines. (It assumed
1945 that signed right shift sign-extends.)
1946
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001947- operator: Add contains(), invert(), __invert__() as aliases for
1948 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001949
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001950- os: Add support for popen2() and popen3() on all platforms where
1951 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001952
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001953- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00001954 clicking on a file in Explorer (or passing the file name to the
1955 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001956
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001957- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00001958 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001959
1960- pickle: Now raises ValueError when an invalid pickle that contains
1961 a non-string repr where a string repr was expected. This behavior
1962 matches cPickle.
1963
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001964- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001965
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001966- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001967
1968- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001969 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001970 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001971
1972- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001973 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001974
1975- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00001976 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00001977 few cycles during startup since the first call to
1978 setdefaultencoding() will initialize the codec registry and the
1979 encodings package.
1980
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001981- socket: Support for size hint in readlines() method of object returned
1982 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001983
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001984- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001985 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001986 is followed by whitespace.
1987
Tim Petersa3a3a032000-11-30 05:22:44 +00001988- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001989
1990- struct: Check ranges for bytes and shorts.
1991
1992- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001993 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001994
1995- Tkinter: Image objects are now guaranteed to have unique ids. Set
1996 event.delta to zero if Tk version doesn't support mousewheel.
1997 Removed some debugging prints.
1998
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001999- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002000
Fred Drake67233bc2000-09-26 16:40:27 +00002001- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002002 which works around a bug in Norton AntiVirus 2000 that leads directly
2003 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002004
2005- xml: New version detection code allows PyXML to override standard
2006 XML package if PyXML version is greater than 0.6.1.
2007
Fred Drake64bb3802000-09-26 16:21:35 +00002008- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2009 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2010 tree only for nodes which are sufficiently interesting to a specific
2011 application. Does not provide the HTML-specific extensions. Still
2012 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002013
Fred Drake64bb3802000-09-26 16:21:35 +00002014- xml.sax: SAX 2 support for Python, including all the handler
2015 interfaces needed to process XML 1.0 compliant XML. Some
2016 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002017
Fred Drake64bb3802000-09-26 16:21:35 +00002018- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2019 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002020
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002021
Jeremy Hylton1b618592000-09-26 05:32:36 +00002022C API
2023
2024- Add three new convenience functions for module initialization --
2025 PyModule_AddObject(), PyModule_AddIntConstant(), and
2026 PyModule_AddStringConstant().
2027
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002028- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002029 removed and add #error to Python.h if NULL isn't defined after
2030 #include of stdio.h.
2031
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002032- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002033 backwards compatibility (at the source level) with old extensions.
2034
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002035- A wrapper API was added for signal() and sigaction(). Instead of
2036 either function, always use PyOS_getsig() to get a signal handler
2037 and PyOS_setsig() to set one. A new convenience typedef
2038 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002039
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002040- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002041 internal data buffer and size of a string object -- or the default
2042 encoded version of a Unicode object.
2043
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002044- PyString_Size() and PyString_AsString() accept Unicode objects.
2045
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002046- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002047 exists). INT_MAX and LONG_MAX will always be defined, even if
2048 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002049
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002050- PyFloat_FromString takes a second argument, pend, that was
2051 effectively useless. It is now officially useless but preserved for
2052 backwards compatibility. If the pend argument is not NULL, *pend is
2053 set to NULL.
2054
2055- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2056 for the attribute name. See note on getattr() above.
2057
2058- A few bug fixes to argument processing for Unicode.
2059 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2060 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2061 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002062 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002063
2064- Py_BuildValue accepts B format (for bgen-generated code).
2065
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002066
Jeremy Hylton1b618592000-09-26 05:32:36 +00002067Internals
2068
2069- On Unix, fix code for finding Python installation directory so that
2070 it works when argv[0] is a relative path.
2071
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002072- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002073 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002074 rather than by generating a copy of the object.
2075
Tim Peters482c0212000-09-26 06:33:09 +00002076- Several of the internal Unicode tables are much smaller now, and
2077 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002078
Jeremy Hylton97693b02000-09-26 17:42:51 +00002079- In the garbage collector: Fixed bug in collection of tuples. Fixed
2080 bug that caused some instances to be removed from the container set
2081 while they were still live. Fixed parsing in gc.set_debug() for
2082 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002083
2084- Fixed refcount problem in instance deallocation that only occurred
2085 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2086
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002087- On Windows, getpythonregpath is now protected against null data in
2088 registry key.
2089
2090- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002091 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002092
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002093
Jeremy Hylton1b618592000-09-26 05:32:36 +00002094Build and platform-specific issues
2095
2096- Better support of GNU Pth via --with-pth configure option.
2097
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002098- Python/C API now properly exposed to dynamically-loaded extension
2099 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002100
2101- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2102 Don't define MS_SYNC to be zero when it is undefined. Added missing
2103 prototypes in posixmodule.c.
2104
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002105- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002106 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002107
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002108- Fix largefile support on older NetBSD systems and OpenBSD by adding
2109 define for TELL64.
2110
2111
2112Tools and other miscellany
2113
2114- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2115
2116- freeze: The modulefinder now works with 2.0 opcodes.
2117
Tim Petersa3a3a032000-11-30 05:22:44 +00002118- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002119 Move hackery of sys.argv until after the Tk instance has been
2120 created, which allows the application-specific Tkinter
2121 initialization to be executed if present; also pass an explicit
2122 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002123
Jeremy Hylton1b618592000-09-26 05:32:36 +00002124
2125What's new in 2.0 beta 1?
2126=========================
2127
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002128Source Incompatibilities
2129------------------------
2130
2131None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2132such as single-argument append(), connect() and bind(), and changes to
2133str(long) and repr(float).
2134
2135
2136Binary Incompatibilities
2137------------------------
2138
2139- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2140with Python 2.0; these extensions will have to be rebuilt for Python
21412.0.
2142
2143- On Windows, attempting to import a third party extension built for
2144Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2145can do about this. Check your PYTHONPATH environment variable!
2146
2147- Python bytecode files (*.pyc and *.pyo) are not compatible between
2148releases.
2149
2150
2151Overview of Changes Since 1.6
2152-----------------------------
2153
2154There are many new modules (including brand new XML support through
2155the xml package, and i18n support through the gettext module); a list
2156of all new modules is included below. Lots of bugs have been fixed.
2157
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002158The process for making major new changes to the language has changed
2159since Python 1.6. Enhancements must now be documented by a Python
2160Enhancement Proposal (PEP) before they can be accepted.
2161
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002162There are several important syntax enhancements, described in more
2163detail below:
2164
2165 - Augmented assignment, e.g. x += 1
2166
2167 - List comprehensions, e.g. [x**2 for x in range(10)]
2168
2169 - Extended import statement, e.g. import Module as Name
2170
2171 - Extended print statement, e.g. print >> file, "Hello"
2172
2173Other important changes:
2174
2175 - Optional collection of cyclical garbage
2176
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002177Python Enhancement Proposal (PEP)
2178---------------------------------
2179
2180PEP stands for Python Enhancement Proposal. A PEP is a design
2181document providing information to the Python community, or describing
2182a new feature for Python. The PEP should provide a concise technical
2183specification of the feature and a rationale for the feature.
2184
2185We intend PEPs to be the primary mechanisms for proposing new
2186features, for collecting community input on an issue, and for
2187documenting the design decisions that have gone into Python. The PEP
2188author is responsible for building consensus within the community and
2189documenting dissenting opinions.
2190
2191The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002192
2193Augmented Assignment
2194--------------------
2195
2196This must have been the most-requested feature of the past years!
2197Eleven new assignment operators were added:
2198
Guido van Rossume905e952000-09-05 12:42:46 +00002199 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002200
2201For example,
2202
2203 A += B
2204
2205is similar to
2206
2207 A = A + B
2208
2209except that A is evaluated only once (relevant when A is something
2210like dict[index].attr).
2211
2212However, if A is a mutable object, A may be modified in place. Thus,
2213if A is a number or a string, A += B has the same effect as A = A+B
2214(except A is only evaluated once); but if a is a list, A += B has the
2215same effect as A.extend(B)!
2216
2217Classes and built-in object types can override the new operators in
2218order to implement the in-place behavior; the not-in-place behavior is
2219used automatically as a fallback when an object doesn't implement the
2220in-place behavior. For classes, the method name is derived from the
2221method name for the corresponding not-in-place operator by inserting
2222an 'i' in front of the name, e.g. __iadd__ implements in-place
2223__add__.
2224
2225Augmented assignment was implemented by Thomas Wouters.
2226
2227
2228List Comprehensions
2229-------------------
2230
2231This is a flexible new notation for lists whose elements are computed
2232from another list (or lists). The simplest form is:
2233
2234 [<expression> for <variable> in <sequence>]
2235
Guido van Rossum56db0952000-09-06 23:34:25 +00002236For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002237This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002238
2239You can also add a condition:
2240
2241 [<expression> for <variable> in <sequence> if <condition>]
2242
2243For example, [w for w in words if w == w.lower()] would yield the list
2244of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002245than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002246
2247You can also have nested for loops and more than one 'if' clause. For
2248example, here's a function that flattens a sequence of sequences::
2249
2250 def flatten(seq):
2251 return [x for subseq in seq for x in subseq]
2252
2253 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2254
2255This prints
2256
2257 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2258
2259List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002260Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002261
2262
2263Extended Import Statement
2264-------------------------
2265
2266Many people have asked for a way to import a module under a different
2267name. This can be accomplished like this:
2268
2269 import foo
2270 bar = foo
2271 del foo
2272
2273but this common idiom gets old quickly. A simple extension of the
2274import statement now allows this to be written as follows:
2275
2276 import foo as bar
2277
2278There's also a variant for 'from ... import':
2279
2280 from foo import bar as spam
2281
2282This also works with packages; e.g. you can write this:
2283
2284 import test.regrtest as regrtest
2285
2286Note that 'as' is not a new keyword -- it is recognized only in this
2287context (this is only possible because the syntax for the import
2288statement doesn't involve expressions).
2289
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002290Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002291
2292
2293Extended Print Statement
2294------------------------
2295
2296Easily the most controversial new feature, this extension to the print
2297statement adds an option to make the output go to a different file
2298than the default sys.stdout.
2299
2300For example, to write an error message to sys.stderr, you can now
2301write:
2302
2303 print >> sys.stderr, "Error: bad dog!"
2304
2305As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002306evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002307
2308 print >> None, "Hello world"
2309
2310is equivalent to
2311
2312 print "Hello world"
2313
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002314Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002315
2316
2317Optional Collection of Cyclical Garbage
2318---------------------------------------
2319
2320Python is now equipped with a garbage collector that can hunt down
2321cyclical references between Python objects. It's no replacement for
2322reference counting; in fact, it depends on the reference counts being
2323correct, and decides that a set of objects belong to a cycle if all
2324their reference counts can be accounted for from their references to
2325each other. This devious scheme was first proposed by Eric Tiedemann,
2326and brought to implementation by Neil Schemenauer.
2327
2328There's a module "gc" that lets you control some parameters of the
2329garbage collection. There's also an option to the configure script
2330that lets you enable or disable the garbage collection. In 2.0b1,
2331it's on by default, so that we (hopefully) can collect decent user
2332experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002333performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002334off by default in the final 2.0 release.
2335
2336
2337Smaller Changes
2338---------------
2339
2340A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2341map(None, seq1, seq2, ...) when the sequences have the same length;
2342i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2343the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002344zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002345
2346sys.version_info is a tuple (major, minor, micro, level, serial).
2347
2348Dictionaries have an odd new method, setdefault(key, default).
2349dict.setdefault(key, default) returns dict[key] if it exists; if not,
2350it sets dict[key] to default and returns that value. Thus:
2351
2352 dict.setdefault(key, []).append(item)
2353
2354does the same work as this common idiom:
2355
2356 if not dict.has_key(key):
2357 dict[key] = []
2358 dict[key].append(item)
2359
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002360There are two new variants of SyntaxError that are raised for
2361indentation-related errors: IndentationError and TabError.
2362
2363Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2364escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002365
2366The limits on the size of expressions and file in Python source code
2367have been raised from 2**16 to 2**32. Previous versions of Python
2368were limited because the maximum argument size the Python VM accepted
2369was 2**16. This limited the size of object constructor expressions,
2370e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2371limit was raised thanks to a patch by Charles Waldman that effectively
2372fixes the problem. It is now much more likely that you will be
2373limited by available memory than by an arbitrary limit in Python.
2374
2375The interpreter's maximum recursion depth can be modified by Python
2376programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2377limit is the maximum number of recursive calls that can be made by
2378Python code. The limit exists to prevent infinite recursion from
2379overflowing the C stack and causing a core dump. The default value is
23801000. The maximum safe value for a particular platform can be found
2381by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002382
2383New Modules and Packages
2384------------------------
2385
2386atexit - for registering functions to be called when Python exits.
2387
2388imputil - Greg Stein's alternative API for writing custom import
2389hooks.
2390
2391pyexpat - an interface to the Expat XML parser, contributed by Paul
2392Prescod.
2393
2394xml - a new package with XML support code organized (so far) in three
2395subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2396would fill a volume. There's a special feature whereby a
2397user-installed package named _xmlplus overrides the standard
2398xmlpackage; this is intended to give the XML SIG a hook to distribute
2399backwards-compatible updates to the standard xml package.
2400
2401webbrowser - a platform-independent API to launch a web browser.
2402
2403
Guido van Rossume905e952000-09-05 12:42:46 +00002404Changed Modules
2405---------------
2406
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002407array -- new methods for array objects: count, extend, index, pop, and
2408remove
2409
2410binascii -- new functions b2a_hex and a2b_hex that convert between
2411binary data and its hex representation
2412
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002413calendar -- Many new functions that support features including control
2414over which day of the week is the first day, returning strings instead
2415of printing them. Also new symbolic constants for days of week,
2416e.g. MONDAY, ..., SUNDAY.
2417
2418cgi -- FieldStorage objects have a getvalue method that works like a
2419dictionary's get method and returns the value attribute of the object.
2420
2421ConfigParser -- The parser object has new methods has_option,
2422remove_section, remove_option, set, and write. They allow the module
2423to be used for writing config files as well as reading them.
2424
2425ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002426optionally support the RFC 959 REST command.
2427
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002428gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002429
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002430httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2431the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002432
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002433locale -- implement getdefaultlocale for Win32 and Macintosh
2434
2435marshal -- no longer dumps core when marshaling deeply nested or
2436recursive data structures
2437
2438os -- new functions isatty, seteuid, setegid, setreuid, setregid
2439
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002440os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2441support under Unix.
2442
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002443os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002444
2445os.path -- fix semantics of os.path.commonprefix
2446
2447smtplib -- support for sending very long messages
2448
2449socket -- new function getfqdn()
2450
2451readline -- new functions to read, write and truncate history files.
2452The readline section of the library reference manual contains an
2453example.
2454
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002455select -- add interface to poll system call
2456
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002457shutil -- new copyfileobj function
2458
2459SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2460HTTP server.
2461
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002462Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002463
2464urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002465e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002466
2467whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002468
2469
2470Obsolete Modules
2471----------------
2472
2473None. However note that 1.6 made a whole slew of modules obsolete:
2474stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2475poly, zmod, strop, util, whatsound.
2476
2477
2478Changed, New, Obsolete Tools
2479----------------------------
2480
Tim Peters8b092332000-09-05 20:15:25 +00002481None.
Guido van Rossume905e952000-09-05 12:42:46 +00002482
2483
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002484C-level Changes
2485---------------
2486
2487Several cleanup jobs were carried out throughout the source code.
2488
2489All C code was converted to ANSI C; we got rid of all uses of the
2490Py_PROTO() macro, which makes the header files a lot more readable.
2491
2492Most of the portability hacks were moved to a new header file,
2493pyport.h; several other new header files were added and some old
2494header files were removed, in an attempt to create a more rational set
2495of header files. (Few of these ever need to be included explicitly;
2496they are all included by Python.h.)
2497
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002498Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002499and Win64, especially for the new Intel Itanium processor. Mick also
2500added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002501
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002502The C APIs to return an object's size have been update to consistently
2503use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2504previous versions, the abstract interfaces used PyXXX_Length and the
2505concrete interfaces used PyXXX_Size. The old names,
2506e.g. PyObject_Length, are still available for backwards compatibility
2507at the API level, but are deprecated.
2508
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002509The PyOS_CheckStack function has been implemented on Windows by
2510Fredrik Lundh. It prevents Python from failing with a stack overflow
2511on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002512
2513The GC changes resulted in creation of two new slots on object,
2514tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002515the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002516
2517The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002518C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002519
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002520PyErr_Format has been updated to automatically calculate the size of
2521the buffer needed to hold the formatted result string. This change
2522prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002523
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002524New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002525
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002526PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2527that are the same as their non-Ex counterparts except they take an
2528extra flag argument that tells them to close the file when done.
2529
2530XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002531
Tim Peters8b092332000-09-05 20:15:25 +00002532
2533Windows Changes
2534---------------
2535
2536New popen2/popen3/peopen4 in os module (see Changed Modules above).
2537
2538os.popen is much more usable on Windows 95 and 98. See Microsoft
2539Knowledge Base article Q150956. The Win9x workaround described there
2540is implemented by the new w9xpopen.exe helper in the root of your
2541Python installation. Note that Python uses this internally; it is not
2542a standalone program.
2543
2544Administrator privileges are no longer required to install Python
2545on Windows NT or Windows 2000. If you have administrator privileges,
2546Python's registry info will be written under HKEY_LOCAL_MACHINE.
2547Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002548under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002549uses of Python, but will prevent some advanced uses from working
2550(for example, running a Python script as an NT service, or possibly
2551from CGI).
2552
2553[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2554installer; instead, it installs the needed Tcl/Tk files directly in the
2555Python directory. If you already have a Tcl/Tk installation, this
2556wastes some disk space (about 4 Megs) but avoids problems with
2557conflicting Tcl/Tk installations, and makes it much easier for Python
2558to ensure that Tcl/Tk can find all its files.
2559
2560[This was new in 1.6] The Windows installer now installs by default in
2561\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2562
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002563
2564Updates to the changes between 1.5.2 and 1.6
2565--------------------------------------------
2566
2567The 1.6 NEWS file can't be changed after the release is done, so here
2568is some late-breaking news:
2569
2570New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2571and changes to getlocale() and setlocale().
2572
2573The new module is now enabled per default.
2574
2575It is not true that the encodings codecs cannot be used for normal
2576strings: the string.encode() (which is also present on 8-bit strings
2577!) allows using them for 8-bit strings too, e.g. to convert files from
2578cp1252 (Windows) to latin-1 or vice-versa.
2579
2580Japanese codecs are available from Tamito KAJIYAMA:
2581http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2582
2583
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002584======================================================================