blob: 1b2b76b9578859248ccc0231d7085edca69e8b79 [file] [log] [blame]
Tim Petersabf925f2001-09-28 21:53:42 +00001What's New in Python 2.2b1?
2Release date: 28-Sep-2100
3===========================
4
5Type/class unification and new-style classes
6
7Core
8
9Library
10
11Tools
12
13Build
14
15C API
16
Tim Petersd38b1c72001-09-30 05:09:37 +000017- PyLong_AsLongLong() now accepts int (as well as long) arguments.
18 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
19 as long) arguments.
20
Tim Petersabf925f2001-09-28 21:53:42 +000021New platforms
22
23Tests
24
25Windows
26
27
Tim Petersb07352e2001-09-08 01:25:47 +000028What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +000029Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +000030===========================
31
Guido van Rossum808eea72001-09-25 04:15:41 +000032Type/class unification and new-style classes
33
34- pydoc and inspect are now aware of new-style classes;
35 e.g. help(list) at the interactive prompt now shows proper
36 documentation for all operations on list objects.
37
38- Applications using Jim Fulton's ExtensionClass module can now safely
39 be used with Python 2.2. In particular, Zope 2.4.1 now works with
40 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
41 examples also work again. It is hoped that Gtk and Boost also work
42 with 2.2a4 and beyond. (If you can confirm this, please write
43 webmaster@python.org; if there are still problems, please open a bug
44 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +000045
Tim Peters66c1a522001-09-24 21:17:50 +000046- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
47 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
48 in the constructed property object. fget, fset and fdel weren't
49 discoverable from Python in 2.2a3. __doc__ is new, and allows to
50 associate a docstring with a property.
51
Guido van Rossum808eea72001-09-25 04:15:41 +000052- Comparison overloading is now more completely implemented. For
53 example, a str subclass instance can properly be compared to a str
54 instance, and it can properly overload comparison. Ditto for most
55 other built-in object types.
56
57- The repr() of new-style classes has changed; instead of <type
58 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
59 *except* for built-in types, which are still rendered as <type
60 'Foo'> (to avoid upsetting existing code that might parse or
61 otherwise rely on repr() of certain type objects).
62
63- The repr() of new-style objects is now always <Foo object at XXX>;
64 previously, it was sometimes <Foo instance at XXX>.
65
66- For new-style classes, what was previously called __getattr__ is now
67 called __getattribute__. This method, if defined, is called for
68 *every* attribute access. A new __getattr__ hook mor similar to the
69 one in classic classes is defined which is called only if regular
70 attribute access raises AttributeError; to catch *all* attribute
71 access, you can use __getattribute__ (for new-style classes). If
72 both are defined, __getattribute__ is called first, and if it raises
73 AttributeError, __getattr__ is called.
74
75- The __class__ attribute of new-style objects can be assigned to.
76 The new class must have the same C-level object layout as the old
77 class.
78
79- The builtin file type can be subclassed now. In the usual pattern,
80 "file" is the name of the builtin type, and file() is a new builtin
81 constructor, with the same signature as the builtin open() function.
82 file() is now the preferred way to open a file.
83
84- Previously, __new__ would only see sequential arguments passed to
85 the type in a constructor call; __init__ would see both sequential
86 and keyword arguments. This made no sense whatsoever any more, so
87 now both __new__ and __init__ see all arguments.
88
89- Previously, hash() applied to an instance of a subclass of str or
90 unicode always returned 0. This has been repaired.
91
92- Previously, an operation on an instance of a subclass of an
93 immutable type (int, long, float, complex, tuple, str, unicode),
94 where the subtype didn't override the operation (and so the
95 operation was handled by the builtin type), could return that
96 instance instead a value of the base type. For example, if s was of
97 a str sublass type, s[:] returned s as-is. Now it returns a str
98 with the same value as s.
99
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000100- Provisional support for pickling new-style objects has been added.
101
Guido van Rossum808eea72001-09-25 04:15:41 +0000102Core
103
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000104- file.writelines() now accepts any iterable object producing strings.
105
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000106- PyUnicode_FromEncodedObject() now works very much like
107 PyObject_Str(obj) in that it tries to use __str__/tp_str
108 on the object if the object is not a string or buffer. This
109 makes unicode() behave like str() when applied to non-string/buffer
110 objects.
111
Martin v. Löwis2777c022001-09-19 13:47:32 +0000112- PyFile_WriteObject now passes Unicode object to the file's write
113 method. As a result, all file-like object which may be the target
114 of a print statement must support Unicode objects, i.e. they must
115 at least convert them into ASCII strings.
116
Guido van Rossum624c8af2001-09-18 15:21:04 +0000117- Thread scheduling on Solaris should be improved; it is no longer
118 necessary to insert a small sleep at the start of a thread in order
119 to let other runnable threads be scheduled.
120
Tim Petersb07352e2001-09-08 01:25:47 +0000121Library
122
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000123- StringIO.StringIO instances and cStringIO.StringIO instances support
124 read character buffer compatible objects for their .write() methods.
125 These objects are converted to strings and then handled as such
126 by the instances.
127
Barry Warsaw2f600732001-09-24 04:28:10 +0000128- The "email" package has been added. This is basically a port of the
129 mimelib package <http://sf.net/projects/mimelib> with API changes
130 and some implementations updated to use iterators and generators.
131
Tim Peters8a9c2842001-09-22 21:30:22 +0000132- difflib.ndiff() and difflib.Differ.compare() are generators now. This
133 restores the ability of Tools/scripts/ndiff.py to start producing output
134 before the entire comparison is complete.
135
Barry Warsaw58b072d2001-09-22 04:44:21 +0000136- StringIO.StringIO instances and cStringIO.StringIO instances support
137 iteration just like file objects (i.e. their .readline() method is
138 called for each iteration until it returns an empty string).
139
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000140- The codecs module has grown four new helper APIs to access
141 builtin codecs: getencoder(), getdecoder(), getreader(),
142 getwriter().
143
Guido van Rossum624c8af2001-09-18 15:21:04 +0000144- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
145 simplifies writing XML RPC servers.
146
Barry Warsaw647d5e82001-09-28 17:01:02 +0000147- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000148 after interpretation of symbolic links. On non-Unix systems, this
149 is an alias for os.path.abspath().
150
Tim Peters16a77ad2001-09-08 04:00:12 +0000151- operator.indexOf() (PySequence_Index() in the C API) now works with any
152 iterable object.
153
Guido van Rossum624c8af2001-09-18 15:21:04 +0000154- smtplib now supports various authentication and security features of
155 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000156
Guido van Rossum624c8af2001-09-18 15:21:04 +0000157- hmac: a new module implementing keyed hashing for message
158 authentication.
159
160- mimetypes now recognizes more extensions and file types. At the
161 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000162
Guido van Rossum624c8af2001-09-18 15:21:04 +0000163- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000164 Python 2.2 bytecode generation. It has also been promoted from a
165 Tool to a standard library package. (Tools/compiler still exists as
166 a sample driver.)
167
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000168Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000169
Tim Petersb07352e2001-09-08 01:25:47 +0000170Build
171
Guido van Rossum624c8af2001-09-18 15:21:04 +0000172- Large file support (LFS) is now automatic when the platform supports
173 it; no more manual configuration tweaks are needed. On Linux, at
174 least, it's possible to have a system whose C library supports large
175 files but whose kernel doesn't; in this case, large file support is
176 still enabled but doesn't do you any good unless you upgrade your
177 kernel or share your Python executable with another system whose
178 kernel has large file support.
179
180- The configure script now supplies plausible defaults in a
181 cross-compilation environment. This doesn't mean that the supplied
182 values are always correct, or that cross-compilation now works
183 flawlessly -- but it's a first step (and it shuts up most of
184 autoconf's warnings about AC_TRY_RUN).
185
186- The Unix build is now a bit less chatty, courtesy of the parser
187 generator. The build is completely silent (except for errors) when
188 using "make -s", thanks to a -q option to setup.py.
189
Tim Petersb07352e2001-09-08 01:25:47 +0000190C API
191
Guido van Rossum624c8af2001-09-18 15:21:04 +0000192- The "structmember" API now supports some new flag bits to deny read
193 and/or write access to attributes in restricted execution mode.
194
Tim Petersb07352e2001-09-08 01:25:47 +0000195New platforms
196
Guido van Rossum624c8af2001-09-18 15:21:04 +0000197- Compaq's iPAQ handheld, running the "familiar" Linux distribution
198 (http://familiar.handhelds.org).
199
Tim Petersb07352e2001-09-08 01:25:47 +0000200Tests
201
Tim Peters8a9c2842001-09-22 21:30:22 +0000202- The "classic" standard tests, which work by comparing stdout to
203 an expected-output file under Lib/test/output/, no longer stop at
204 the first mismatch. Instead the test is run to completion, and a
205 variant of ndiff-style comparison is used to report all differences.
206 This is much easier to understand than the previous style of reporting.
207
208- The unittest-based standard tests now use regrtest's test_main()
209 convention, instead of running as a side-effect of merely being
210 imported. This allows these tests to be run in more natural and
211 flexible ways as unittests, outside the regrtest framework.
212
213- regrtest.py is much better integrated with unittest and doctest now,
214 especially in regard to reporting errors.
215
Tim Petersb07352e2001-09-08 01:25:47 +0000216Windows
217
Guido van Rossum624c8af2001-09-18 15:21:04 +0000218- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000219 that support it (NTFS under Windows 2000). See "What's New in
220 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000221
Tim Petersb07352e2001-09-08 01:25:47 +0000222
Tim Petersedc99312001-08-22 21:36:50 +0000223What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000224Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000225===========================
226
227Core
228
Tim Peters9fffa3e2001-09-04 05:14:19 +0000229- Conversion of long to float now raises OverflowError if the long is too
230 big to represent as a C double.
231
Tim Peters32f453e2001-09-03 08:35:41 +0000232- The 3-argument builtin pow() no longer allows a third non-None argument
233 if either of the first two arguments is a float, or if both are of
234 integer types and the second argument is negative (in which latter case
235 the arguments are converted to float, so this is really the same
236 restriction).
237
Tim Peters5d2b77c2001-09-03 05:47:38 +0000238- The builtin dir() now returns more information, and sometimes much
239 more, generally naming all attributes of an object, and all attributes
240 reachable from the object via its class, and from its class's base
241 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
242 an empty list. In 2.2a3,
243
244 >>> dir([])
245 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
246 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
247 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
248 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
249 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
250 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
251 'reverse', 'sort']
252
253 dir(module) continues to return only the module's attributes, though.
254
Tim Petersbdee63f2001-09-02 03:40:59 +0000255- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000256 than raising OverflowError. This is a partial implementation of PEP
257 237. You can use -Wdefault::OverflowWarning to enable a warning for
258 this situation, and -Werror::OverflowWarning to revert to the old
259 OverflowError exception.
260
Guido van Rossum61c345f2001-09-04 03:26:15 +0000261- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000262 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000263 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
264 -Qold, meaning the / operator has its classic meaning and no
265 warnings are issued. Using -Qwarn issues a run-time warning about
266 all uses of classic division for int and long arguments; -Qwarnall
267 also warns about classic division for float and complex arguments
268 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
269 new division by default, but only in the __main__ module. You can
270 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
271 __main__ module new division, and warns about classic division
272 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000273
Tim Petersbdee63f2001-09-02 03:40:59 +0000274- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000275 long, float, str, unicode, and tuple. (The types complex, list and
276 dictionary can also be subclassed; this was introduced earlier.)
277 Note that restrictions apply when subclassing immutable built-in
278 types: you can only affect the value of the instance by overloading
279 __new__. You can add mutable attributes, and the subclass instances
280 will have a __dict__ attribute, but you cannot change the "value"
281 (as implemented by the base class) of an immutable subclass instance
282 once it is created.
283
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000284- The dictionary constructor now takes an optional argument, a
285 mapping-like object, and initializes the dictionary from its
286 (key, value) pairs.
287
Tim Petersbdee63f2001-09-02 03:40:59 +0000288- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000289 "cooperative super calls" in a multiple inheritance setting. For an
290 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
291
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000292- A new built-in type, property, has been added. This enables the
293 creation of "properties". These are attributes implemented by
294 getter and setter functions (or only one of these for read-only or
295 write-only attributes), without the need to override __getattr__.
296 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000297
Tim Petersbdee63f2001-09-02 03:40:59 +0000298- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000299 liberalized, to allow leading zeroes. Examples of literals now
300 legal that were SyntaxErrors before:
301
302 00.0 0e3 0100j 07.5 00000000000000000008.
303
Tim Petersbdee63f2001-09-02 03:40:59 +0000304- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000305 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
306
Tim Petersedc99312001-08-22 21:36:50 +0000307Library
308
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000309- telnetlib includes symbolic names for the options, and support for
310 setting an option negotiation callback.
311
Tim Petersa40c7932001-09-05 22:36:56 +0000312- The new C standard no longer requires that math libraries set errno to
313 ERANGE on overflow. For platform libraries that exploit this new
314 freedom, Python's overflow-checking was wholly broken. A new overflow-
315 checking scheme attempts to repair that, but may not be reliable on all
316 platforms (C doesn't seem to provide anything both useful and portable
317 in this area anymore).
318
Martin v. Löwis44f86962001-09-05 13:44:54 +0000319- Asynchronous timeout actions are available through the new class
320 threading.Timer.
321
Tim Peters78526162001-09-05 00:53:45 +0000322- math.log and math.log10 now return sensible results for even huge
323 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
324
Tim Petersbdee63f2001-09-02 03:40:59 +0000325- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000326 currently held. See the docs for the imp module.
327
Tim Petersbdee63f2001-09-02 03:40:59 +0000328- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000329 dumps containing ints written on platforms where Python ints are 8 bytes.
330 When read on a box where Python ints are 4 bytes, such values are
331 converted to Python longs.
332
Tim Petersbdee63f2001-09-02 03:40:59 +0000333- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000334 code objects is no longer allowed. This plugs a security hole.
335
Steve Purcell6091cd62001-09-06 16:05:17 +0000336- unittest.TestResult instances no longer store references to tracebacks
337 generated by test failures. This prevents unexpected dangling references
338 to objects that should be garbage collected between tests.
339
Tim Petersedc99312001-08-22 21:36:50 +0000340Tools
341
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000342- Tools/scripts/fixdiv.py has been added which can be used to fix
343 division operators as per PEP 238.
344
Tim Petersedc99312001-08-22 21:36:50 +0000345Build
346
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000347- If you are an adventurous person using Mac OS X you may want to look at
348 Mac/OSX. There is a Makefile there that will build Python as a real Mac
349 application, which can be used for experimenting with Carbon or Cocoa.
350 Discussion of this on pythonmac-sig, please.
351
Tim Peters7eea37e2001-09-04 22:08:56 +0000352C API
353
354- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000355
Tim Peters9fffa3e2001-09-04 05:14:19 +0000356- Note that PyLong_AsDouble can fail! This has always been true, but no
357 callers checked for it. It's more likely to fail now, because overflow
358 errors are properly detected now. The proper way to check:
359
360 double x = PyLong_AsDouble(some_long_object);
361 if (x == -1.0 && PyErr_Occurred()) {
362 /* The conversion failed. */
363 }
364
Tim Petersbdee63f2001-09-02 03:40:59 +0000365- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000366 compile but will not participate in GC. To upgrade an extension
367 module:
368
369 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000370
Neil Schemenauer4042c692001-08-30 15:38:01 +0000371 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
372 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000373
Neil Schemenauer4042c692001-08-30 15:38:01 +0000374 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
375 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000376
Neil Schemenauer4042c692001-08-30 15:38:01 +0000377 - remove PyGC_HEAD_SIZE from object size calculations
378
379 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
380
Tim Petersbdee63f2001-09-02 03:40:59 +0000381- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000382 These can be used safely to construct string objects from a
383 sprintf-style format string (similar to the format string supported
384 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000385
Tim Petersedc99312001-08-22 21:36:50 +0000386New platforms
387
Tim Petersb7da0902001-09-02 23:01:43 +0000388- Stephen Hansen contributed patches sufficient to get a clean compile
389 under Borland C (Windows), but he reports problems running it and ran
390 out of time to complete the port. Volunteers? Expect a MemoryError
391 when importing the types module; this is probably shallow, and
392 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000393
Tim Petersedc99312001-08-22 21:36:50 +0000394Tests
395
396Windows
397
Tim Peters6e13a562001-09-06 00:32:15 +0000398- Large file support is now enabled on Win32 platforms as well as on
399 Win64. This means that, for example, you can use f.tell() and f.seek()
400 to manipulate files larger than 2 gigabytes (provided you have enough
401 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000402 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
403 filesize limit, and large file support makes no difference there.
404 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
405 NTFS has no practical limit on file size, and files of any size can be
406 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000407
Tim Petersbdee63f2001-09-02 03:40:59 +0000408- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000409 points to command.com (patch from Brian Quinlan).
410
Tim Petersedc99312001-08-22 21:36:50 +0000411
Tim Peters20f51a72001-07-21 02:31:40 +0000412What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000413Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000414===========================
415
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000416Build
417
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000418- Tim Peters developed a brand new Windows installer using Wise 8.1,
419 generously donated to us by Wise Solutions.
420
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000421- configure supports a new option --enable-unicode, with the values
422 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
423 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000424
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000425- A new configure option --enable-framework builds a Mac OS X framework,
426 which "make frameworkinstall" will install. This provides a starting
427 point for more mac-like functionality, join pythonmac-sig@python.org
428 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000429
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000430- The NeXT platform is no longer supported.
431
432- The `new' module is now statically linked.
433
Tim Peters0afb6092001-08-15 06:06:44 +0000434Tools
435
436- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000437 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000438 the module docstring for details.
439
Tim Peters20f51a72001-07-21 02:31:40 +0000440Tests
441
Tim Peters5e824c32001-08-12 22:25:01 +0000442- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000443 platforms, allowing to give clearer test result output. regrtest
444 also has optional --use/-u switch to run normally disabled tests
445 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000446
Tim Peters20f51a72001-07-21 02:31:40 +0000447- Several new tests in the standard test suite, with special thanks to
448 Nick Mathewson.
449
450Core
451
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000452- The floor division operator // has been added as outlined in PEP
453 238. The / operator still provides classic division (and will until
454 Python 3.0) unless "from __future__ import division" is included, in
455 which case the / operator will provide true division. The operator
456 module provides truediv() and floordiv() functions. Augmented
457 assignment variants are included, as are the equivalent overloadable
458 methods and C API methods. See the PEP for a full discussion:
459 <http://python.sf.net/peps/pep-0238.html>
460
Tim Peters6cd6a822001-08-17 22:11:27 +0000461- Future statements are now effective in simulated interactive shells
462 (like IDLE). This should "just work" by magic, but read Michael
463 Hudson's "Future statements in simulated shells" PEP 264 for full
464 details: <http://python.sf.net/peps/pep-0264.html>.
465
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000466- The type/class unification (PEP 252-253) was integrated into the
467 trunk and is not so tentative any more (the exact specification of
468 some features is still tentative). A lot of work has done on fixing
469 bugs and adding robustness and features (performance still has to
470 come a long way).
471
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000472- Warnings about a mismatch in the Python API during extension import
473 now use the Python warning framework (which makes it possible to
474 write filters for these warnings).
475
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000476- A function's __dict__ (aka func_dict) will now always be a
477 dictionary. It used to be possible to delete it or set it to None,
478 but now both actions raise TypeErrors. It is still legal to set it
479 to a dictionary object. Getting func.__dict__ before any attributes
480 have been assigned now returns an empty dictionary instead of None.
481
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000482- A new command line option, -E, was added which disables the use of
483 all environment variables, or at least those that are specifically
484 significant to Python. Usually those have a name starting with
485 "PYTHON". This was used to fix a problem where the tests fail if
486 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
487 older distribution.
488
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000489Library
490
Tim Peters5e824c32001-08-12 22:25:01 +0000491- New class Differ and new functions ndiff() and restore() in difflib.py.
492 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000493 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000494
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000495- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
496 value using the minimal quoting required for the value; more
497 reliable than using xml.sax.saxutils.escape() for attribute values.
498
499- Readline completion support for cmd.Cmd was added.
500
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000501- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
502
503- Added function threading.BoundedSemaphore()
504
505- Added Ka-Ping Yee's cgitb.py module.
506
507- The `new' module now exposes the CO_xxx flags.
508
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000509New platforms
510
511C API
512
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000513- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
514 which provide a cross-platform implementations for the
515 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
516 the standard sprintf() and vsprintf() C lib APIs, these versions
517 apply bounds checking on the used buffer which enhances protection
518 against buffer overruns.
519
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000520- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000521 and extensions using different Unicode widths is rendered next to
522 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000523 will result in an ImportError. Unicode extensions writers must make
524 sure to check the Unicode width compatibility in their extensions by
525 using at least one of the mangled Unicode APIs in the extension.
526
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000527- Two new flags METH_NOARGS and METH_O are available in method definition
528 tables to simplify implementation of methods with no arguments and a
529 single untyped argument. Calling such methods is more efficient than
530 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
531 deprecated.
532
Tim Petersc1731372001-08-04 08:12:36 +0000533Windows
534
535- "import module" now compiles module.pyw if it exists and nothing else
536 relevant is found.
537
Tim Peters20f51a72001-07-21 02:31:40 +0000538
Guido van Rossum55a78992001-07-17 17:22:32 +0000539What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +0000540===========================
541
542Core
Tim Petersa814db52001-05-14 07:05:58 +0000543
Tim Peters6d6c1a32001-08-02 04:15:00 +0000544- TENTATIVELY, a large amount of code implementing much of what's
545 described in PEP 252 (Making Types Look More Like Classes) and PEP
546 253 (Subtyping Built-in Types) was added. This will be released
547 with Python 2.2a1. Documentation will be provided separately
548 through http://www.python.org/2.2/. The purpose of releasing this
549 with Python 2.2a1 is to test backwards compatibility. It is
550 possible, though not likely, that a decision is made not to release
551 this code as part of 2.2 final, if any serious backwards
552 incompapatibilities are found during alpha testing that cannot be
553 repaired.
554
Guido van Rossum55a78992001-07-17 17:22:32 +0000555- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000556 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000557 more 'yield' statements. See PEP 255. Since this adds a new
558 keyword to the language, this feature must be enabled by including a
559 future statement: "from __future__ import generators" (see PEP 236).
560 Generators will become a standard feature in a future release
561 (probably 2.3). Without this future statement, 'yield' remains an
562 ordinary identifier, but a warning is issued each time it is used.
563 (These warnings currently don't conform to the warnings framework of
564 PEP 230; we intend to fix this in 2.2a2.)
565
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000566- The UTF-16 codec was modified to be more RFC compliant. It will now
567 only remove BOM characters at the start of the string and then
568 only if running in native mode (UTF-16-LE and -BE won't remove a
569 leading BMO character).
570
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000571- Strings now have a new method .decode() to complement the already
572 existing .encode() method. These two methods provide direct access
573 to the corresponding decoders and encoders of the registered codecs.
574
575 To enhance the usability of the .encode() method, the special
576 casing of Unicode object return values was dropped (Unicode objects
577 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000578
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000579 Both methods will now return whatever the codec in charge of the
580 requested encoding returns as object, e.g. Unicode codecs will
581 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
582 will return u"äöü"). This enables codec writer to create codecs
583 for various simple to use conversions.
584
585 New codecs were added to demonstrate these new features (the .encode()
586 and .decode() columns indicate the type of the returned objects):
587
588 Name | .encode() | .decode() | Description
589 ----------------------------------------------------------------------
590 uu | string | string | UU codec (e.g. for email)
591 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000592 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000593 zlib | string | string | zlib compression
594 hex | string | string | 2-byte hex codec
595 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
596
Mark Hammond2a0af792001-05-14 03:09:36 +0000597- Some operating systems now support the concept of a default Unicode
598 encoding for file system operations. Notably, Windows supports 'mbcs'
599 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000600 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000601 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000602
603 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000604 functions that return filenames (such as os.listdir()) to return Python
605 string objects pre-encoded using the default file system encoding for
606 the platform. As this encoding is likely to be different from Python's
607 default encoding, converting this name to a Unicode object before passing
608 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000609 would attempt to use its default encoding (generally ASCII) rather than
610 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000611
Tim Petersa814db52001-05-14 07:05:58 +0000612 In general, this change simply removes surprises when working with
613 Unicode and the file system, making these operations work as you expect,
614 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000615 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000616
Tim Peters61dff2b2001-05-08 15:43:37 +0000617- Float (and complex) literals in source code were evaluated to full
618 precision only when running from a .py file; the same code loaded from a
619 .pyc (or .pyo) file could suffer numeric differences starting at about the
620 12th significant decimal digit. For example, on a machine with IEEE-754
621 floating arithmetic,
622
623 x = 9007199254740992.0
624 print long(x)
625
626 printed 9007199254740992 if run directly from .py, but 9007199254740000
627 if from a compiled (.pyc or .pyo) file. This was due to marshal using
628 str(float) instead of repr(float) when building code objects. marshal
629 now uses repr(float) instead, which should reproduce floats to full
630 machine precision (assuming the platform C float<->string I/O conversion
631 functions are of good quality).
632
633 This may cause floating-point results to change in some cases, and
634 usually for the better, but may also cause numerically unstable
635 algorithms to break.
636
Tim Peters2f228e72001-05-13 00:19:31 +0000637- The implementation of dicts suffers fewer collisions, which has speed
638 benefits. However, the order in which dict entries appear in dict.keys(),
639 dict.values() and dict.items() may differ from previous releases for a
640 given dict. Nothing is defined about this order, so no program should
641 rely on it. Nevertheless, it's easy to write test cases that rely on the
642 order by accident, typically because of printing the str() or repr() of a
643 dict to an "expected results" file. See Lib/test/test_support.py's new
644 sortdict(dict) function for a simple way to display a dict in sorted
645 order.
646
Tim Peters7a3bfc32001-06-12 01:22:22 +0000647- Many other small changes to dicts were made, resulting in faster
648 operation along the most common code paths.
649
Guido van Rossum10315822001-05-01 20:54:30 +0000650- Dictionary objects now support the "in" operator: "x in dict" means
651 the same as dict.has_key(x).
652
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000653- The update() method of dictionaries now accepts generic mapping
654 objects. Specifically the argument object must support the .keys()
655 and __getitem__() methods. This allows you to say, for example,
656 {}.update(UserDict())
657
Guido van Rossum10315822001-05-01 20:54:30 +0000658- Iterators were added; this is a generalized way of providing values
659 to a for loop. See PEP 234. There's a new built-in function iter()
660 to return an iterator. There's a new protocol to get the next value
661 from an iterator using the next() method (in Python) or the
662 tp_iternext slot (in C). There's a new protocol to get iterators
663 using the __iter__() method (in Python) or the tp_iter slot (in C).
664 Iterating (i.e. a for loop) over a dictionary generates its keys.
665 Iterating over a file generates its lines.
666
Tim Petersf553f892001-05-01 20:45:31 +0000667- The following functions were generalized to work nicely with iterator
668 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000669 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000670 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
671 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000672 join() method of strings
673 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000674 'x in y' and 'x not in y' (PySequence_Contains() in C API)
675 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000676 right-hand side of assignment statements with multiple targets, such as
677 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000678
Tim Petersd85e1022001-05-11 21:51:48 +0000679- Accessing module attributes is significantly faster (for example,
680 random.random or os.path or yourPythonModule.yourAttribute).
681
Tim Peterse63415e2001-05-08 04:38:29 +0000682- Comparing dictionary objects via == and != is faster, and now works even
683 if the keys and values don't support comparisons other than ==.
684
Tim Peters95bf9392001-05-10 08:32:44 +0000685- Comparing dictionaries in ways other than == and != is slower: there were
686 insecurities in the dict comparison implementation that could cause Python
687 to crash if the element comparison routines for the dict keys and/or
688 values mutated the dicts. Making the code bulletproof slowed it down.
689
Tim Peterseb28ef22001-06-02 05:27:19 +0000690- Collisions in dicts are resolved via a new approach, which can help
691 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000692 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000693 faster now. Thanks to Christian Tismer for pointing out the cause and
694 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000695
Tim Peters52e155e2001-06-16 05:42:57 +0000696- repr() is much faster for large containers (dict, list, tuple).
697
698
Tim Petersa814db52001-05-14 07:05:58 +0000699Library
700
Fred Drake960fdf92001-07-20 18:38:26 +0000701- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
702 were added to the string module. These a locale-indenpendent
703 constants, unlike letters, lowercase, and uppercase. These are now
704 use in appropriate locations in the standard library.
705
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000706- The flags used in dlopen calls can now be configured using
707 sys.setdlopenflags and queried using sys.getdlopenflags.
708
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000709- Fredrik Lundh's xmlrpclib is now a standard library module. This
710 provides full client-side XML-RPC support. In addition,
711 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
712 one asyncore-based). Thanks to Eric Raymond for the documentation.
713
Guido van Rossum643d3912001-07-05 14:46:25 +0000714- The xrange() object is simplified: it no longer supports slicing,
715 repetition, comparisons, efficient 'in' checking, the tolist()
716 method, or the start, stop and step attributes. See PEP 260.
717
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000718- A new function fnmatch.filter to filter lists of file names was added.
719
Barry Warsawffd674d2001-05-22 16:00:10 +0000720- calendar.py uses month and day names based on the current locale.
721
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000722- strop is now *really* obsolete (this was announced before with 1.6),
723 and issues DeprecationWarning when used (except for the four items
724 that are still imported into string.py).
725
Tim Petersa814db52001-05-14 07:05:58 +0000726- Cookie.py now sorts key+value pairs by key in output strings.
727
728- pprint.isrecursive(object) didn't correctly identify recursive objects.
729 Now it does.
730
Tim Peters95b3f782001-05-14 18:39:41 +0000731- pprint functions now much faster for large containers (tuple, list, dict).
732
Tim Peters7b9542a2001-06-10 23:40:19 +0000733- New 'q' and 'Q' format codes in the struct module, corresponding to C
734 types "long long" and "unsigned long long" (on Windows, __int64). In
735 native mode, these can be used only when the platform C compiler supports
736 these types (when HAVE_LONG_LONG is #define'd by the Python config
737 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000738 In standard mode, 'q' and 'Q' are supported on all platforms, and are
739 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000740
Guido van Rossum83213cc2001-06-12 16:48:52 +0000741- The site module installs a new built-in function 'help' that invokes
742 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
743 it displays a message reminding the user to use 'help()' or
744 'help(object)'.
745
Tim Petersa814db52001-05-14 07:05:58 +0000746Tests
747
748- New test_mutants.py runs dict comparisons where the key and value
749 comparison operators mutute the dicts randomly during comparison. This
750 rapidly causes Python to crash under earlier releases (not for the faint
751 of heart: it can also cause Win9x to freeze or reboot!).
752
753- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000754 pprint.isreadable() return sensible results. Also verifies that simple
755 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000756
Tim Peters4324aa32001-05-28 22:30:08 +0000757C API
758
759- Removed the unused last_is_sticky argument from the internal
760 _PyTuple_Resize(). If this affects you, you were cheating.
761
762
Guido van Rossum55a78992001-07-17 17:22:32 +0000763======================================================================
764
765
Guido van Rossumffe13be2001-04-16 18:46:45 +0000766What's New in Python 2.1 (final)?
767=================================
768
769We only changed a few things since the last release candidate, all in
770Python library code:
771
772- A bug in the locale module was fixed that affected locales which
773 define no grouping for numeric formatting.
774
775- A few bugs in the weakref module's implementations of weak
776 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
777 and the test suite was updated to check for these bugs.
778
779- An old bug in the os.path.walk() function (introduced in Python
780 2.0!) was fixed: a non-existent file would cause an exception
781 instead of being ignored.
782
783- Fixed a few bugs in the new symtable module found by Neil Norwitz's
784 PyChecker.
785
786
Guido van Rossum5b08f132001-04-16 02:05:23 +0000787What's New in Python 2.1c2?
788===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000789
Guido van Rossum5b08f132001-04-16 02:05:23 +0000790A flurry of small changes, and one showstopper fixed in the nick of
791time made it necessary to release another release candidate. The list
792here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000793
Guido van Rossum5b08f132001-04-16 02:05:23 +0000794Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000795
Guido van Rossum5b08f132001-04-16 02:05:23 +0000796- Tim discovered a nasty bug in the dictionary code, caused by
797 PyDict_Next() calling dict_resize(), and the GC code's use of
798 PyDict_Next() violating an assumption in dict_items(). This was
799 fixed with considerable amounts of band-aid, but the net effect is a
800 saner and more robust implementation.
801
802- Made a bunch of symbols static that were accidentally global.
803
804Build and Ports
805
806- The setup.py script didn't check for a new enough version of zlib
807 (1.1.3 is needed). Now it does.
808
809- Changed "make clean" target to also remove shared libraries.
810
811- Added a more general warning about the SGI Irix optimizer to README.
812
813Library
814
815- Fix a bug in urllib.basejoin("http://host", "../file.html") which
816 omitted the slash between host and file.html.
817
818- The mailbox module's _Mailbox class contained a completely broken
819 and undocumented seek() method. Ripped it out.
820
821- Fixed a bunch of typos in various library modules (urllib2, smtpd,
822 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
823
824- Fixed a few last-minute bugs in unittest.
825
826Extensions
827
828- Reverted the patch to the OpenSSL code in socketmodule.c to support
829 RAND_status() and the EGD, and the subsequent patch that tried to
830 fix it for pre-0.9.5 versions; the problem with the patch is that on
831 some systems it issues a warning whenever socket is imported, and
832 that's unacceptable.
833
834Tests
835
836- Fixed the pickle tests to work with "import test.test_pickle".
837
838- Tweaked test_locale.py to actually run the test Windows.
839
840- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
841 not "wb" (which is not a valid mode at all).
842
843- Fix pstats browser crashes. Import readline if it exists to make
844 the user interface nicer.
845
846- Add "import thread" to the top of test modules that import the
847 threading module (test_asynchat and test_threadedtempfile). This
848 prevents test failures caused by a broken threading module resulting
849 from a previously caught failed import.
850
851- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
852 needed on some platforms (e.g. Solaris 8) when the tests are run
853 twice in succession.
854
855- Skip rather than fail test_sunaudiodev if no audio device is found.
856
857
858What's New in Python 2.1c1?
859===========================
860
861This list was significantly updated when 2.1c2 was released; the 2.1c1
862release didn't mention most changes that were actually part of 2.1c1:
863
864Legal
865
866- Copyright was assigned to the Python Software Foundation (PSF) and a
867 PSF license (very similar to the CNRI license) was added.
868
869- The CNRI copyright notice was updated to include 2001.
870
871Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000872
Guido van Rossumc9932722001-04-12 02:31:27 +0000873- After a public outcry, assignment to __debug__ is no longer illegal;
874 instead, a warning is issued. It will become illegal in 2.2.
875
Guido van Rossum5b08f132001-04-16 02:05:23 +0000876- Fixed a core dump with "%#x" % 0, and changed the semantics so that
877 "%#x" now always prepends "0x", even if the value is zero.
878
879- Fixed some nits in the bytecode compiler.
880
881- Fixed core dumps when calling certain kinds of non-functions.
882
883- Fixed various core dumps caused by reference count bugs.
884
885Build and Ports
886
887- Use INSTALL_SCRIPT to install script files.
888
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000889- New port: SCO Unixware 7, by Billy G. Allie.
890
Guido van Rossum5b08f132001-04-16 02:05:23 +0000891- Updated RISCOS port.
892
893- Updated BeOS port and notes.
894
895- Various other porting problems resolved.
896
897Library
898
899- The TERMIOS and SOCKET modules are now truly obsolete and
900 unnecessary. Their symbols are incorporated in the termios and
901 socket modules.
902
903- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
904 better tests for pickling.
905
906- threading: make Condition.wait() robust against KeyboardInterrupt.
907
908- zipfile: add support to zipfile to support opening an archive
909 represented by an open file rather than a file name. Fix bug where
910 the archive was not properly closed. Fixed a bug in this bugfix
911 where flush() was called for a read-only file.
912
913- imputil: added an uninstall() method to the ImportManager.
914
915- Canvas: fixed bugs in lower() and tkraise() methods.
916
917- SocketServer: API change (added overridable close_request() method)
918 so that the TCP server can explicitly close the request.
919
920- pstats: Eric Raymond added a simple interactive statistics browser,
921 invoked when the module is run as a script.
922
923- locale: fixed a problem in format().
924
925- webbrowser: made it work when the BROWSER environment variable has a
926 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
927 KDE 2. Fixed some other nits.
928
929- unittest: changes to allow using a different exception than
930 AssertionError, and added a few more function aliases. Some other
931 small changes.
932
933- urllib, urllib2: fixed redirect problems and a coupleof other nits.
934
935- asynchat: fixed a critical bug in asynchat that slipped through the
936 2.1b2 release. Fixed another rare bug.
937
938- Fix some unqualified except: clauses (always a bad code example).
939
940XML
941
942- pyexpat: new API get_version_string().
943
944- Fixed some minidom bugs.
945
946Extensions
947
948- Fixed a core dump in _weakref. Removed the weakref.mapping()
949 function (it adds nothing to the API).
950
951- Rationalized the use of header files in the readline module, to make
952 it compile (albeit with some warnings) with the very recent readline
953 4.2, without breaking for earlier versions.
954
955- Hopefully fixed a buffering problem in linuxaudiodev.
956
957- Attempted a fix to make the OpenSSL support in the socket module
958 work again with pre-0.9.5 versions of OpenSSL.
959
960Tests
961
962- Added a test case for asynchat and asyncore.
963
964- Removed coupling between tests where one test failing could break
965 another.
966
967Tools
968
969- Ping added an interactive help browser to pydoc, fixed some nits
970 in the rest of the pydoc code, and added some features to his
971 inspect module.
972
973- An updated python-mode.el version 4.1 which integrates Ken
974 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
975 much nicer in XEmacs and Emacs. When stepping through your program
976 with pdb, in either the shell window or the *Python* window, the
977 source file and line will be tracked by an arrow. Very cool!
978
979- IDLE: syntax warnings in interactive mode are changed into errors.
980
981- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +0000982 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +0000983
984- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000985
Barry Warsaw11e89c72001-04-11 20:37:57 +0000986
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000987What's New in Python 2.1 beta 2?
988================================
989
Guido van Rossum053ae352001-03-22 14:17:21 +0000990(Unlisted are many fixed bugs, more documentation, etc.)
991
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000992Core language, builtins, and interpreter
993
Guido van Rossum053ae352001-03-22 14:17:21 +0000994- The nested scopes work (enabled by "from __future__ import
995 nested_scopes") is completed; in particular, the future now extends
996 into code executed through exec, eval() and execfile(), and into the
997 interactive interpreter.
998
999- When calling a base class method (e.g. BaseClass.__init__(self)),
1000 this is now allowed even if self is not strictly spoken a class
1001 instance (e.g. when using metaclasses or the Don Beaudry hook).
1002
1003- Slice objects are now comparable but not hashable; this prevents
1004 dict[:] from being accepted but meaningless.
1005
1006- Complex division is now calculated using less braindead algorithms.
1007 This doesn't change semantics except it's more likely to give useful
1008 results in extreme cases. Complex repr() now uses full precision
1009 like float repr().
1010
1011- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1012
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001013- It is illegal to assign to the name __debug__, which is set when the
1014 interpreter starts. It is effectively a compile-time constant.
1015
1016- A warning will be issued if a global statement for a variable
1017 follows a use or assignment of that variable.
1018
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001019Standard library
1020
Guido van Rossum053ae352001-03-22 14:17:21 +00001021- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1022 inspired by JUnit), is now part of the standard library. You now
1023 have a choice of two testing frameworks: unittest requires you to
1024 write testcases as separate code, doctest gathers them from
1025 docstrings. Both approaches have their advantages and
1026 disadvantages.
1027
1028- A new module Tix was added, which wraps the Tix extension library
1029 for Tk. With that module, it is not necessary to statically link
1030 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1031 require" command. See Demo/tix/.
1032
1033- tzparse.py is now obsolete.
1034
1035- In gzip.py, the seek() and tell() methods are removed -- they were
1036 non-functional anyway, and it's better if callers can test for their
1037 existence with hasattr().
1038
1039Python/C API
1040
1041- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1042 that's already in the dictionary during a PyDict_Next() iteration.
1043 This used to fail occasionally when a dictionary resize operation
1044 could be triggered that would rehash all the keys. All other
1045 modifications to the dictionary are still off-limits during a
1046 PyDict_Next() iteration!
1047
1048- New extended APIs related to passing compiler variables around.
1049
1050- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1051 implement isinstance() and issubclass().
1052
1053- Py_BuildValue() now has a "D" conversion to create a Python complex
1054 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001055
Fred Drake4e262a92001-03-22 18:26:47 +00001056- Extensions types which support weak references must now set the
1057 field allocated for the weak reference machinery to NULL themselves;
1058 this is done to avoid the cost of checking each object for having a
1059 weakly referencable type in PyObject_INIT(), since most types are
1060 not weakly referencable.
1061
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001062- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1063 free variables and cell variables to and from the frame's f_locals.
1064
1065- Variants of several functions defined in pythonrun.h have been added
1066 to support the nested_scopes future statement. The variants all end
1067 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1068 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1069 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001070 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001071
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001072Distutils
1073
1074- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1075 into the release tree.
1076
Tim Peters0e57abf2001-05-02 07:39:38 +00001077- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001078 (an uninstaller, more customization of the installer's display)
1079
1080- from Jack Jansen: added Mac-specific code to generate a dialog for
1081 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001082 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001083 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001084
1085- added 'platforms' and 'keywords' to the set of metadata that can be
1086 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001087
1088- applied patches from Jason Tishler to make the compiler class work with
1089 Cygwin.
1090
1091
Tim Peters2fe289a2001-03-01 22:19:38 +00001092What's New in Python 2.1 beta 1?
1093================================
Tim Petersd66595f2001-02-04 03:09:53 +00001094
1095Core language, builtins, and interpreter
1096
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001097- Following an outcry from the community about the amount of code
1098 broken by the nested scopes feature introduced in 2.1a2, we decided
1099 to make this feature optional, and to wait until Python 2.2 (or at
1100 least 6 months) to make it standard. The option can be enabled on a
1101 per-module basis by adding "from __future__ import nested_scopes" at
1102 the beginning of a module (before any other statements, but after
1103 comments and an optional docstring). See PEP 236 (Back to the
1104 __future__) for a description of the __future__ statement. PEP 227
1105 (Statically Nested Scopes) has been updated to reflect this change,
1106 and to clarify the semantics in a number of endcases.
1107
1108- The nested scopes code, when enabled, has been hardened, and most
1109 bugs and memory leaks in it have been fixed.
1110
1111- Compile-time warnings are now generated for a number of conditions
1112 that will break or change in meaning when nested scopes are enabled:
1113
1114 - Using "from...import *" or "exec" without in-clause in a function
1115 scope that also defines a lambda or nested function with one or
1116 more free (non-local) variables. The presence of the import* or
1117 bare exec makes it impossible for the compiler to determine the
1118 exact set of local variables in the outer scope, which makes it
1119 impossible to determine the bindings for free variables in the
1120 inner scope. To avoid the warning about import *, change it into
1121 an import of explicitly name object, or move the import* statement
1122 to the global scope; to avoid the warning about bare exec, use
1123 exec...in... (a good idea anyway -- there's a possibility that
1124 bare exec will be deprecated in the future).
1125
1126 - Use of a global variable in a nested scope with the same name as a
1127 local variable in a surrounding scope. This will change in
1128 meaning with nested scopes: the name in the inner scope will
1129 reference the variable in the outer scope rather than the global
1130 of the same name. To avoid the warning, either rename the outer
1131 variable, or use a global statement in the inner function.
1132
Neil Schemenauera35c6882001-02-27 04:45:05 +00001133- An optional object allocator has been included. This allocator is
1134 optimized for Python objects and should be faster and use less memory
1135 than the standard system allocator. It is not enabled by default
1136 because of possible thread safety problems. The allocator is only
1137 protected by the Python interpreter lock and it is possible that some
1138 extension modules require a thread safe allocator. The object
1139 allocator can be enabled by providing the "--with-pymalloc" option to
1140 configure.
1141
Tim Petersd66595f2001-02-04 03:09:53 +00001142Standard library
1143
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001144- pyexpat now detects the expat version if expat.h defines it. A
1145 number of additional handlers are provided, which are only available
1146 since expat 1.95. In addition, the methods SetParamEntityParsing and
1147 GetInputContext of Parser objects are available with 1.95.x
1148 only. Parser objects now provide the ordered_attributes and
1149 specified_attributes attributes. A new module expat.model was added,
1150 which offers a number of additional constants if 1.95.x is used.
1151
1152- xml.dom offers the new functions registerDOMImplementation and
1153 getDOMImplementation.
1154
1155- xml.dom.minidom offers a toprettyxml method. A number of DOM
1156 conformance issues have been resolved. In particular, Element now
1157 has an hasAttributes method, and the handling of namespaces was
1158 improved.
1159
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001160- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1161 getting information about live Python code, and pydoc.py, a module
1162 for interactively converting docstrings to HTML or text.
1163 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001164 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001165 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1166 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001167
Tim Peters1eff7962001-03-01 02:31:33 +00001168- New library module difflib.py, primarily packaging the SequenceMatcher
1169 class at the heart of the popular ndiff.py file-comparison tool.
1170
1171- doctest.py (a framework for verifying Python code examples in docstrings)
1172 is now part of the std library.
1173
Tim Petersd66595f2001-02-04 03:09:53 +00001174Windows changes
1175
Guido van Rossume3955a82001-03-02 14:05:59 +00001176- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1177 small GUI that lets you browse the module docstrings using your
1178 default web browser.
1179
Tim Peters1eff7962001-03-01 02:31:33 +00001180- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1181 Platforms) is implemented. See
1182
1183 http://python.sourceforge.net/peps/pep-0235.html
1184
1185 for full details, especially the "Current Lower-Left Semantics" section.
1186 The new Windows import rules are simpler than before:
1187
1188 A. If the PYTHONCASEOK environment variable exists, same as
1189 before: silently accept the first case-insensitive match of any
1190 kind; raise ImportError if none found.
1191
1192 B. Else search sys.path for the first case-sensitive match; raise
1193 ImportError if none found.
1194
1195 The same rules have been implented on other platforms with case-
1196 insensitive but case-preserving filesystems too (including Cygwin, and
1197 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001198
Tim Peters25a9ce32001-02-19 07:06:36 +00001199- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1200 what it's supposed to do (and does do under NT and 2000) via direct
1201 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001202 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001203 all Win9x systems before.
1204
Tim Peters1eff7962001-03-01 02:31:33 +00001205- Build: Subproject _test (effectively) renamed to _testcapi.
1206
Tim Peters2fe289a2001-03-01 22:19:38 +00001207New platforms
1208
1209- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1210 Thanks to Steven Majewski!
1211
1212- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1213 Tishler!
1214
Guido van Rossum9089b272001-03-02 06:49:50 +00001215- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1216 Schwertberger! See RISCOS/README for more information -- it seems
1217 that because of the bizarre filename conventions on RISCOS, no port
1218 to that platform is easy. Note that the new variable os.endsep is
1219 silently supported in order to make life easier on this platform,
1220 but we don't advertise it because it's not worth for most folks to
1221 care about RISCOS portability.
1222
Tim Peters25a9ce32001-02-19 07:06:36 +00001223
Tim Petersd7b5e882001-01-25 03:36:26 +00001224What's New in Python 2.1 alpha 2?
1225=================================
Tim Peters40ead762001-01-27 05:35:26 +00001226
Tim Petersd7b5e882001-01-25 03:36:26 +00001227Core language, builtins, and interpreter
1228
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001229- Scopes nest. If a name is used in a function or class, but is not
1230 local, the definition in the nearest enclosing function scope will
1231 be used. One consequence of this change is that lambda statements
1232 could reference variables in the namespaces where the lambda is
1233 defined. In some unusual cases, this change will break code.
1234
1235 In all previous version of Python, names were resolved in exactly
1236 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001237 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001238 function A is defined within a function B, the names bound in B are
1239 not visible in A. The new rules make names bound in B visible in A,
1240 unless A contains a name binding that hides the binding in B.
1241
1242 Section 4.1 of the reference manual describes the new scoping rules
1243 in detail. The test script in Lib/test/test_scope.py demonstrates
1244 some of the effects of the change.
1245
1246 The new rules will cause existing code to break if it defines nested
1247 functions where an outer function has local variables with the same
1248 name as globals or builtins used by the inner function. Example:
1249
1250 def munge(str):
1251 def helper(x):
1252 return str(x)
1253 if type(str) != type(''):
1254 str = helper(str)
1255 return str.strip()
1256
1257 Under the old rules, the name str in helper() is bound to the
1258 builtin function str(). Under the new rules, it will be bound to
1259 the argument named str and an error will occur when helper() is
1260 called.
1261
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001262- The compiler will report a SyntaxError if "from ... import *" occurs
1263 in a function or class scope. The language reference has documented
1264 that this case is illegal, but the compiler never checked for it.
1265 The recent introduction of nested scope makes the meaning of this
1266 form of name binding ambiguous. In a future release, the compiler
1267 may allow this form when there is no possibility of ambiguity.
1268
Tim Peters40ead762001-01-27 05:35:26 +00001269- repr(string) is easier to read, now using hex escapes instead of octal,
1270 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1271
1272 >>> "\texample \r\n" + chr(0) + chr(255)
1273 '\texample \r\n\x00\xff' # in 2.1
1274 '\011example \015\012\000\377' # in 2.0
1275
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001276- Functions are now compared and hashed by identity, not by value, since
1277 the func_code attribute is writable.
1278
Fred Drakefb9d7122001-02-01 20:00:40 +00001279- Weak references (PEP 205) have been added. This involves a few
1280 changes in the core, an extension module (_weakref), and a Python
1281 module (weakref). The weakref module is the public interface. It
1282 includes support for "explicit" weak references, proxy objects, and
1283 mappings with weakly held values.
1284
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001285- A 'continue' statement can now appear in a try block within the body
1286 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001287 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001288
Tim Petersd7b5e882001-01-25 03:36:26 +00001289Standard library
1290
Barry Warsaw30dbd142001-01-31 22:14:01 +00001291- mailbox.py now has a new class, PortableUnixMailbox which is
1292 identical to UnixMailbox but uses a more portable scheme for
1293 determining From_ separators. Also, the constructors for all the
1294 classes in this module have a new optional `factory' argument, which
1295 is a callable used when new message classes must be instantiated by
1296 the next() method.
1297
Tim Petersd7b5e882001-01-25 03:36:26 +00001298- random.py is now self-contained, and offers all the functionality of
1299 the now-deprecated whrandom.py. See the docs for details. random.py
1300 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001301 and restoring the internal state of the generator; and jumpahead(n),
1302 for quickly forcing the internal state to be the same as if n calls to
1303 random() had been made. The latter is particularly useful for multi-
1304 threaded programs, creating one instance of the random.Random() class for
1305 each thread, then using .jumpahead() to force each instance to use a
1306 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001307
Tim Peters0de88fc2001-02-01 04:59:18 +00001308- random.py's seed() function is new. For bit-for-bit compatibility with
1309 prior releases, use the whseed function instead. The new seed function
1310 addresses two problems: (1) The old function couldn't produce more than
1311 about 2**24 distinct internal states; the new one about 2**45 (the best
1312 that can be done in the Wichmann-Hill generator). (2) The old function
1313 sometimes produced identical internal states when passed distinct
1314 integers, and there was no simple way to predict when that would happen;
1315 the new one guarantees to produce distinct internal states for all
1316 arguments in [0, 27814431486576L).
1317
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001318- The socket module now supports raw packets on Linux. The socket
1319 family is AF_PACKET.
1320
Tim Peters9ea17ac2001-02-02 05:57:15 +00001321- test_capi.py is a start at running tests of the Python C API. The tests
1322 are implemented by the new Modules/_testmodule.c.
1323
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001324- A new extension module, _symtable, provides provisional access to the
1325 internal symbol table used by the Python compiler. A higher-level
1326 interface will be added on top of _symtable in a future release.
1327
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001328- Removed the obsolete soundex module.
1329
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001330- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1331 the isSameNode method; NamedNodeMap the get method.
1332
1333- xml.sax.expatreader supports the lexical handler property; it
1334 generates comment, startCDATA, and endCDATA events.
1335
Tim Petersee826f82001-01-31 19:39:44 +00001336Windows changes
1337
1338- Build procedure: the zlib project is built in a different way that
1339 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001340 the zlib binary used. See PCbuild\readme.txt for details. Your old
1341 zlib-related directories can be deleted; you'll need to download fresh
1342 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001343
Tim Peters9ea17ac2001-02-02 05:57:15 +00001344- Build: New subproject _test for the benefit of test_capi.py (see above).
1345
Tim Petersb16c56f2001-02-02 21:24:51 +00001346- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1347 interface to some Python compiler internals).
1348
1349- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001350 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001351
Tim Petersa3a3a032000-11-30 05:22:44 +00001352What's New in Python 2.1 alpha 1?
1353=================================
1354
1355Core language, builtins, and interpreter
1356
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001357- There is a new Unicode companion to the PyObject_Str() API
1358 called PyObject_Unicode(). It behaves in the same way as the
1359 former, but assures that the returned value is an Unicode object
1360 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001361
Guido van Rossumf98eda02001-01-17 15:54:45 +00001362- The comparison operators support "rich comparison overloading" (PEP
1363 207). C extension types can provide a rich comparison function in
1364 the new tp_richcompare slot in the type object. The cmp() function
1365 and the C function PyObject_Compare() first try the new rich
1366 comparison operators before trying the old 3-way comparison. There
1367 is also a new C API PyObject_RichCompare() (which also falls back on
1368 the old 3-way comparison, but does not constrain the outcome of the
1369 rich comparison to a Boolean result).
1370
1371 The rich comparison function takes two objects (at least one of
1372 which is guaranteed to have the type that provided the function) and
1373 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1374 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1375 object, which may be NotImplemented (in which case the tp_compare
1376 slot function is used as a fallback, if defined).
1377
1378 Classes can overload individual comparison operators by defining one
1379 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001380 __ge__. There are no explicit "reflected argument" versions of
1381 these; instead, __lt__ and __gt__ are each other's reflection,
1382 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1383 reflection (similar at the C level). No other implications are
1384 made; in particular, Python does not assume that == is the Boolean
1385 inverse of !=, or that < is the Boolean inverse of >=. This makes
1386 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001387
1388 Classes or types that want to implement (in)equality tests but not
1389 the ordering operators (i.e. unordered types) should implement ==
1390 and !=, and raise an error for the ordering operators.
1391
Guido van Rossuma88479f2001-01-18 14:28:08 +00001392 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001393 Boolean; e.g. a matrix type might want to return a matrix of bits
1394 for A < B, giving elementwise comparisons. Such types should ensure
1395 that any interpretation of their value in a Boolean context raises
1396 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1397 at the C level) to always raise an exception.
1398
Guido van Rossuma88479f2001-01-18 14:28:08 +00001399- Complex numbers use rich comparisons to define == and != but raise
1400 an exception for <, <=, > and >=. Unfortunately, this also means
1401 that cmp() of two complex numbers raises an exception when the two
1402 numbers differ. Since it is not mathematically meaningful to compare
1403 complex numbers except for equality, I hope that this doesn't break
1404 too much code.
1405
Tim Peters3389f192001-02-18 08:48:49 +00001406- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001407 not defined by the language, other than that it's arbitrary but
1408 consistent (see the Reference Manual). An implementation detail changed
1409 in 2.1a1 such that None now compares less than any other object. Code
1410 relying on this new behavior (like code that relied on the previous
1411 behavior) does so at its own risk.
1412
Barry Warsaw573b5412001-01-15 20:43:18 +00001413- Functions and methods now support getting and setting arbitrarily
1414 named attributes (PEP 232). Functions have a new __dict__
1415 (a.k.a. func_dict) which hold the function attributes. Methods get
1416 and set attributes on their underlying im_func. It is a TypeError
1417 to set an attribute on a bound method.
1418
Guido van Rossum051e3352001-01-15 19:11:10 +00001419- The xrange() object implementation has been improved so that
1420 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1421 limitation that in this case len(xrange(sys.maxint)) can't be
1422 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1423 work fine as long as the index i doesn't actually reach 2**31.
1424 (Python uses regular ints for sequence and string indices; fixing
1425 that is much more work.)
1426
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001427- Two changes to from...import:
1428
Guido van Rossumba381232001-02-03 15:06:40 +00001429 1) "from M import X" now works even if (after loading module M)
1430 sys.modules['M'] is not a real module; it's basically a getattr()
1431 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001432
1433 2) "from M import *" now looks for M.__all__ to decide which names to
1434 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1435 filters out names starting with '_' as before. Whether or not
1436 __all__ exists, there's no restriction on the type of M.
1437
Guido van Rossumf61f1662001-01-10 20:13:55 +00001438- File objects have a new method, xreadlines(). This is the fastest
1439 way to iterate over all lines in a file:
1440
1441 for line in file.xreadlines():
1442 ...do something to line...
1443
1444 See the xreadlines module (mentioned below) for how to do this for
1445 other file-like objects.
1446
1447- Even if you don't use file.xreadlines(), you may expect a speedup on
1448 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001449 quite a bit in platform-specific ways: on systems (like Linux) that
1450 support flockfile(), getc_unlocked(), and funlockfile(), those are
1451 used by default. On systems (like Windows) without getc_unlocked(),
1452 a complicated (but still thread-safe) method using fgets() is used by
1453 default.
1454
Tim Petersd52269b2001-01-25 06:23:18 +00001455 You can force use of the fgets() method by #define'ing
1456 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001457 getc_unlocked()).
1458
Tim Petersd52269b2001-01-25 06:23:18 +00001459 You can force fgets() not to be used by #define'ing
1460 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001461 test_bufio.py fails -- and let us know if it does!).
1462
1463- In addition, the fileinput module, while still slower than the other
1464 methods on most platforms, has been sped up too, by using
1465 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001466
1467- Support for run-time warnings has been added, including a new
1468 command line option (-W) to specify the disposition of warnings.
1469 See the description of the warnings module below.
1470
1471- Extensive changes have been made to the coercion code. This mostly
1472 affects extension modules (which can now implement mixed-type
1473 numerical operators without having to use coercion), but
1474 occasionally, in boundary cases the coercion semantics have changed
1475 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001476 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001477 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001478 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001479
Guido van Rossumf98eda02001-01-17 15:54:45 +00001480- In connection with the coercion changes, a new built-in singleton
1481 object, NotImplemented is defined. This can be returned for
1482 operations that wish to indicate they are not implemented for a
1483 particular combination of arguments. From C, this is
1484 Py_NotImplemented.
1485
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001486- The interpreter accepts now bytecode files on the command line even
1487 if they do not have a .pyc or .pyo extension. On Linux, after executing
1488
Martin v. Löwise214baa2001-02-04 22:37:56 +00001489import imp,sys,string
1490magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1491reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1492open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001493
1494 any byte code file can be used as an executable (i.e. as an argument
1495 to execve(2)).
1496
Tim Peters9940b802000-12-01 07:59:35 +00001497- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001498 character. In 1.6 and earlier, they never produced a sign,
1499 and raised an error if the value of the long was too large
1500 to fit in a Python int. In 2.0, they produced a sign if and
1501 only if too large to fit in an int. This was inconsistent
1502 across platforms (because the size of an int varies across
1503 platforms), and inconsistent with hex() and oct(). Example:
1504
1505 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001506 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001507 'ffffffbe' # in 2.0 and before, on 32-bit machines
1508 >>> hex(-0x42L)
1509 '-0x42L' # in all versions of Python
1510
Tim Peters9940b802000-12-01 07:59:35 +00001511 The behavior of %d formats for negative Python longs remains
1512 the same as in 2.0 (although in 1.6 and before, they raised
1513 an error if the long didn't fit in a Python int).
1514
1515 %u formats don't make sense for Python longs, but are allowed
1516 and treated the same as %d in 2.1. In 2.0, a negative long
1517 formatted via %u produced a sign if and only if too large to
1518 fit in an int. In 1.6 and earlier, a negative long formatted
1519 via %u raised an error if it was too big to fit in an int.
1520
Guido van Rossum3661d392000-12-12 22:10:31 +00001521- Dictionary objects have an odd new method, popitem(). This removes
1522 an arbitrary item from the dictionary and returns it (in the form of
1523 a (key, value) pair). This can be useful for algorithms that use a
1524 dictionary as a bag of "to do" items and repeatedly need to pick one
1525 item. Such algorithms normally end up running in quadratic time;
1526 using popitem() they can usually be made to run in linear time.
1527
Tim Peters36cdad12000-12-29 02:06:45 +00001528Standard library
1529
Thomas Woutersfe385252001-01-19 23:16:56 +00001530- In the time module, the time argument to the functions strftime,
1531 localtime, gmtime, asctime and ctime is now optional, defaulting to
1532 the current time (in the local timezone).
1533
Guido van Rossumda91f222001-01-15 16:36:08 +00001534- The ftplib module now defaults to passive mode, which is deemed a
1535 more useful default given that clients are often inside firewalls
1536 these days. Note that this could break if ftplib is used to connect
1537 to a *server* that is inside a firewall, from outside; this is
1538 expected to be a very rare situation. To fix that, you can call
1539 ftp.set_pasv(0).
1540
Martin v. Löwis10a27872001-01-13 09:54:41 +00001541- The module site now treats .pth files not only for path configuration,
1542 but also supports extensions to the initialization code: Lines starting
1543 with import are executed.
1544
Guido van Rossumf61f1662001-01-10 20:13:55 +00001545- There's a new module, warnings, which implements a mechanism for
1546 issuing and filtering warnings. There are some new built-in
1547 exceptions that serve as warning categories, and a new command line
1548 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1549 turns warnings into errors). warnings.warn(message[, category])
1550 issues a warning message; this can also be called from C as
1551 PyErr_Warn(category, message).
1552
1553- A new module xreadlines was added. This exports a single factory
1554 function, xreadlines(). The intention is that this code is the
1555 absolutely fastest way to iterate over all lines in an open
1556 file(-like) object:
1557
1558 import xreadlines
1559 for line in xreadlines.xreadlines(file):
1560 ...do something to line...
1561
1562 This is equivalent to the previous the speed record holder using
1563 file.readlines(sizehint). Note that if file is a real file object
1564 (as opposed to a file-like object), this is equivalent:
1565
1566 for line in file.xreadlines():
1567 ...do something to line...
1568
Tim Peters36cdad12000-12-29 02:06:45 +00001569- The bisect module has new functions bisect_left, insort_left,
1570 bisect_right and insort_right. The old names bisect and insort
1571 are now aliases for bisect_right and insort_right. XXX_right
1572 and XXX_left methods differ in what happens when the new element
1573 compares equal to one or more elements already in the list: the
1574 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001575 right. Code that doesn't care where equal elements end up should
1576 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001577
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001578- The new curses.panel module wraps the panel library that forms part
1579 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1580
Guido van Rossumf61f1662001-01-10 20:13:55 +00001581- The SocketServer module now sets the allow_reuse_address flag by
1582 default in the TCPServer class.
1583
1584- A new function, sys._getframe(), returns the stack frame pointer of
1585 the caller. This is intended only as a building block for
1586 higher-level mechanisms such as string interpolation.
1587
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001588- The pyexpat module supports a number of new handlers, which are
1589 available only in expat 1.2. If invocation of a callback fails, it
1590 will report an additional frame in the traceback. Parser objects
1591 participate now in garbage collection. If expat reports an unknown
1592 encoding, pyexpat will try to use a Python codec; that works only
1593 for single-byte charsets. The parser type objects is exposed as
1594 XMLParserObject.
1595
1596- xml.dom now offers standard definitions for symbolic node type and
1597 exception code constants, and a hierarchy of DOM exceptions. minidom
1598 was adjusted to use them.
1599
1600- The conformance of xml.dom.minidom to the DOM specification was
1601 improved. It detects a number of additional error cases; the
1602 previous/next relationship works even when the tree is modified;
1603 Node supports the normalize() method; NamedNodeMap, DocumentType and
1604 DOMImplementation classes were added; Element supports the
1605 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1606 method.
1607
Guido van Rossumf61f1662001-01-10 20:13:55 +00001608Build issues
1609
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001610- For Unix (and Unix-compatible) builds, configuration and building of
1611 extension modules is now greatly automated. Rather than having to
1612 edit the Modules/Setup file to indicate which modules should be
1613 built and where their include files and libraries are, a
1614 distutils-based setup.py script now takes care of building most
1615 extension modules. All extension modules built this way are built
1616 as shared libraries. Only a few modules that must be linked
1617 statically are still listed in the Setup file; you won't need to
1618 edit their configuration.
1619
1620- Python should now build out of the box on Cygwin. If it doesn't,
1621 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001622
1623- Python now always uses its own (renamed) implementation of getopt()
1624 -- there's too much variation among C library getopt()
1625 implementations.
1626
1627- C++ compilers are better supported; the CXX macro is always set to a
1628 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001629
Tim Petersd92dfe02000-12-12 01:18:41 +00001630Windows changes
1631
1632- select module: By default under Windows, a select() call
1633 can specify no more than 64 sockets. Python now boosts
1634 this Microsoft default to 512. If you need even more than
1635 that, see the MS docs (you'll need to #define FD_SETSIZE
1636 and recompile Python from source).
1637
Guido van Rossumf61f1662001-01-10 20:13:55 +00001638- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1639 subdirectory is no more!
1640
Tim Petersa3a3a032000-11-30 05:22:44 +00001641
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001642What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001643=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001644
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001645Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001646changes are in the file HISTORY. If you are making the jump directly
1647from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1648HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001649
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001650Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1651the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1652http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001653
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001654--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001655
1656======================================================================
1657
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001658What's new in 2.0 (since release candidate 1)?
1659==============================================
1660
1661Standard library
1662
1663- The copy_reg module was modified to clarify its intended use: to
1664 register pickle support for extension types, not for classes.
1665 pickle() will raise a TypeError if it is passed a class.
1666
1667- Fixed a bug in gettext's "normalize and expand" code that prevented
1668 it from finding an existing .mo file.
1669
1670- Restored support for HTTP/0.9 servers in httplib.
1671
Tim Peters989b7b92000-10-16 20:24:53 +00001672- The math module was changed to stop raising OverflowError in case of
1673 underflow, and return 0 instead in underflow cases. Whether Python
1674 used to raise OverflowError in case of underflow was platform-
1675 dependent (it did when the platform math library set errno to ERANGE
1676 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001677
1678- Fixed a bug in StringIO that occurred when the file position was not
1679 at the end of the file and write() was called with enough data to
1680 extend past the end of the file.
1681
1682- Fixed a bug that caused Tkinter error messages to get lost on
1683 Windows. The bug was fixed by replacing direct use of
1684 interp->result with Tcl_GetStringResult(interp).
1685
1686- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1687 redirect response.
1688
1689- Several changes were made to distutils: Some debugging code was
1690 removed from util. Fixed the installer used when an external zip
1691 program (like WinZip) is not found; the source code for this
1692 installer is in Misc/distutils. check_lib() was modified to behave
1693 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1694 test for whether installed modules are on sys.path was changed to
1695 use both normcase() and normpath().
1696
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001697- Several minor bugs were fixed in the xml package (the minidom,
1698 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001699
1700- The regression test driver (regrtest.py) behavior when invoked with
1701 -l changed: It now reports a count of objects that are recognized as
1702 garbage but not freed by the garbage collector.
1703
Tim Peters989b7b92000-10-16 20:24:53 +00001704- The regression test for the math module was changed to test
1705 exceptional behavior when the test is run in verbose mode. Python
1706 cannot yet guarantee consistent exception behavior across platforms,
1707 so the exception part of test_math is run only in verbose mode, and
1708 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001709
1710Internals
1711
1712- PyOS_CheckStack() has been disabled on Win64, where it caused
1713 test_sre to fail.
1714
1715Build issues
1716
1717- Changed compiler flags, so that gcc is always invoked with -Wall and
1718 -Wstrict-prototypes. Users compiling Python with GCC should see
1719 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001720 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001721 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001722
Tim Petersa3a3a032000-11-30 05:22:44 +00001723- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001724
1725Tools and other miscellany
1726
1727- The compiler in Tools/compiler was updated to support the new
1728 language features introduced in 2.0: extended print statement, list
1729 comprehensions, and augmented assignments. The new compiler should
1730 also be backwards compatible with Python 1.5.2; the compiler will
1731 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001732 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001733
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001734What's new in 2.0 release candidate 1 (since beta 2)?
1735=====================================================
1736
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001737What is release candidate 1?
1738
1739We believe that release candidate 1 will fix all known bugs that we
1740intend to fix for the 2.0 final release. This release should be a bit
1741more stable than the previous betas. We would like to see even more
1742widespread testing before the final release, so we are producing this
1743release candidate. The final release will be exactly the same unless
1744any show-stopping (or brown bag) bugs are found by testers of the
1745release candidate.
1746
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001747All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001748to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001749
1750Core language, builtins, and interpreter
1751
1752- A bug that caused crashes when __coerce__ was used with augmented
1753 assignment, e.g. +=, was fixed.
1754
1755- Raise ZeroDivisionError when raising zero to a negative number,
1756 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1757 power operator and the result of math.pow(0.0, -2.0) will vary by
1758 platform. On Linux, it raises a ValueError.
1759
1760- A bug in Unicode string interpolation was fixed that occasionally
1761 caused errors with formats including "%%". For example, the
1762 following expression "%% %s" % u"abc" no longer raises a TypeError.
1763
1764- Compilation of deeply nested expressions raises MemoryError instead
1765 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1766
1767- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1768 rendering them useless. They are now written in binary mode again.
1769
1770Standard library
1771
1772- Keyword arguments are now accepted for most pattern and match object
1773 methods in SRE, the standard regular expression engine.
1774
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001775- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001776 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001777
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001778- Several bugs in the Unicode handling and error handling in _tkinter
1779 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001780
1781- Fix memory management errors in Merge() and Tkapp_Call() routines.
1782
1783- Several changes were made to cStringIO to make it compatible with
1784 the file-like object interface and with StringIO. If operations are
1785 performed on a closed object, an exception is raised. The truncate
1786 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001787 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001788
1789- There were many changes made to the linuxaudiodev module and its
1790 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001791 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001792
1793 Note that this module is named poorly, because it should work
1794 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001795 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001796
1797 The module now raises exceptions when errors occur instead of
1798 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1799 audio) and defines a getptr() method that calls the
1800 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1801
1802- The library_version attribute, introduced in an earlier beta, was
1803 removed because it can not be supported with early versions of the C
1804 readline library, which provides no way to determine the version at
1805 compile-time.
1806
1807- The binascii module is now enabled on Win64.
1808
Tim Peters46446d62000-10-09 21:19:31 +00001809- tokenize.py no longer suffers "recursion depth" errors when parsing
1810 programs with very long string literals.
1811
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001812Internals
1813
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001814- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001815 which is called when the interpreter starts up to determine where
1816 the standard library is installed. These vulnerabilities affect all
1817 previous versions of Python and can be exploited by setting very
1818 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1819 setuid Python script, although use of the wrapper in
1820 Misc/setuid-prog.c will eliminate the vulnerability.
1821
1822- Fixed garbage collection bugs in instance creation that were
1823 triggered when errors occurred during initialization. The solution,
1824 applied in cPickle and in PyInstance_New(), is to call
1825 PyObject_GC_Init() after the initialization of the object's
1826 container attributes is complete.
1827
1828- pyexpat adds definitions of PyModule_AddStringConstant and
1829 PyModule_AddObject if the Python version is less than 2.0, which
1830 provides compatibility with PyXML on Python 1.5.2.
1831
1832- If the platform has a bogus definition for LONG_BIT (the number of
1833 bits in a long), an error will be reported at compile time.
1834
1835- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1836 collection crashes and possibly other, unreported crashes.
1837
1838- Fixed a memory leak in _PyUnicode_Fini().
1839
1840Build issues
1841
1842- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001843 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001844 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001845
1846- The mmap.PAGESIZE constant is now initialized using sysconf when
1847 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1848
1849- The md5 file should now compile on all platforms.
1850
1851- The select module now compiles on platforms that do not define
1852 POLLRDNORM and related constants.
1853
1854- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001855 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001856
Jeremy Hylton10921202000-10-09 18:34:12 +00001857- BeOS: A number of changes were made to the build and installation
1858 process. ar-fake now operates on a directory of object files.
1859 dl_export.h is gone, and its macros now appear on the mwcc command
1860 line during build on PPC BeOS.
1861
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001862- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001863 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001864
1865- Cygwin: Support for shared libraries, Tkinter, and sockets.
1866
1867- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1868
1869Tools and other miscellany
1870
1871- Removed debugging prints from main used with freeze.
1872
Tim Peters46446d62000-10-09 21:19:31 +00001873- IDLE auto-indent no longer crashes when it encounters Unicode
1874 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001875
1876What's new in 2.0 beta 2 (since beta 1)?
1877========================================
1878
1879Core language, builtins, and interpreter
1880
Tim Peters482c0212000-09-26 06:33:09 +00001881- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001882 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001883
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001884- Add -h and -V command line options to print the usage message and
1885 Python version number and exit immediately.
1886
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001887- eval() and exec accept Unicode objects as code parameters.
1888
1889- getattr() and setattr() now also accept Unicode objects for the
1890 attribute name, which are converted to strings using the default
1891 encoding before lookup.
1892
1893- Multiplication on string and Unicode now does proper bounds
1894 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1895 string is too long."
1896
1897- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001898 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001899
Jeremy Hylton1b618592000-09-26 05:32:36 +00001900
1901Standard library and extensions
1902
Guido van Rossum5b08f132001-04-16 02:05:23 +00001903- socket module: the OpenSSL code now adds support for RAND_status()
1904 and EGD (Entropy Gathering Device).
1905
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001906- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001907 argument checking; it still takes no arguments.
1908
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001909- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001910
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001911- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001912
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001913- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001914
1915- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001916 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001917
1918- copy: Copy Unicode objects atomically.
1919
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001920- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001921
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001922- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001923
Fred Drake67233bc2000-09-26 16:40:27 +00001924- dbm: Add get() and setdefault() methods to dbm object. Add constant
1925 `library' to module that names the library used. Added doc strings
1926 and method names to error messages. Uses configure to determine
1927 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
1928 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001929
1930- distutils: Update to version 0.9.3.
1931
1932- dl: Add several dl.RTLD_ constants.
1933
1934- fpectl: Now supported on FreeBSD.
1935
1936- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
1937 found by the collector will be saved in gc.garbage. This is useful
1938 for debugging a program that creates reference cycles.
1939
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001940- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00001941 of HTTP class. Do not close socket on zero-length response. Do not
1942 crash when server sends invalid content-length header.
1943
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001944- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001945
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001946- marshal: When reading a short, sign-extend on platforms where shorts
1947 are bigger than 16 bits. When reading a long, repair the unportable
1948 sign extension that was being done for 64-bit machines. (It assumed
1949 that signed right shift sign-extends.)
1950
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001951- operator: Add contains(), invert(), __invert__() as aliases for
1952 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001953
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001954- os: Add support for popen2() and popen3() on all platforms where
1955 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001956
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001957- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00001958 clicking on a file in Explorer (or passing the file name to the
1959 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001960
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001961- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00001962 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001963
1964- pickle: Now raises ValueError when an invalid pickle that contains
1965 a non-string repr where a string repr was expected. This behavior
1966 matches cPickle.
1967
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001968- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001969
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001970- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001971
1972- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001973 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001974 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001975
1976- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001977 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001978
1979- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00001980 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00001981 few cycles during startup since the first call to
1982 setdefaultencoding() will initialize the codec registry and the
1983 encodings package.
1984
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001985- socket: Support for size hint in readlines() method of object returned
1986 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001987
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001988- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001989 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001990 is followed by whitespace.
1991
Tim Petersa3a3a032000-11-30 05:22:44 +00001992- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001993
1994- struct: Check ranges for bytes and shorts.
1995
1996- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001997 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001998
1999- Tkinter: Image objects are now guaranteed to have unique ids. Set
2000 event.delta to zero if Tk version doesn't support mousewheel.
2001 Removed some debugging prints.
2002
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002003- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002004
Fred Drake67233bc2000-09-26 16:40:27 +00002005- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002006 which works around a bug in Norton AntiVirus 2000 that leads directly
2007 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002008
2009- xml: New version detection code allows PyXML to override standard
2010 XML package if PyXML version is greater than 0.6.1.
2011
Fred Drake64bb3802000-09-26 16:21:35 +00002012- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2013 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2014 tree only for nodes which are sufficiently interesting to a specific
2015 application. Does not provide the HTML-specific extensions. Still
2016 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002017
Fred Drake64bb3802000-09-26 16:21:35 +00002018- xml.sax: SAX 2 support for Python, including all the handler
2019 interfaces needed to process XML 1.0 compliant XML. Some
2020 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002021
Fred Drake64bb3802000-09-26 16:21:35 +00002022- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2023 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002024
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002025
Jeremy Hylton1b618592000-09-26 05:32:36 +00002026C API
2027
2028- Add three new convenience functions for module initialization --
2029 PyModule_AddObject(), PyModule_AddIntConstant(), and
2030 PyModule_AddStringConstant().
2031
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002032- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002033 removed and add #error to Python.h if NULL isn't defined after
2034 #include of stdio.h.
2035
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002036- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002037 backwards compatibility (at the source level) with old extensions.
2038
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002039- A wrapper API was added for signal() and sigaction(). Instead of
2040 either function, always use PyOS_getsig() to get a signal handler
2041 and PyOS_setsig() to set one. A new convenience typedef
2042 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002043
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002044- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002045 internal data buffer and size of a string object -- or the default
2046 encoded version of a Unicode object.
2047
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002048- PyString_Size() and PyString_AsString() accept Unicode objects.
2049
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002050- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002051 exists). INT_MAX and LONG_MAX will always be defined, even if
2052 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002053
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002054- PyFloat_FromString takes a second argument, pend, that was
2055 effectively useless. It is now officially useless but preserved for
2056 backwards compatibility. If the pend argument is not NULL, *pend is
2057 set to NULL.
2058
2059- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2060 for the attribute name. See note on getattr() above.
2061
2062- A few bug fixes to argument processing for Unicode.
2063 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2064 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2065 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002066 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002067
2068- Py_BuildValue accepts B format (for bgen-generated code).
2069
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002070
Jeremy Hylton1b618592000-09-26 05:32:36 +00002071Internals
2072
2073- On Unix, fix code for finding Python installation directory so that
2074 it works when argv[0] is a relative path.
2075
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002076- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002077 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002078 rather than by generating a copy of the object.
2079
Tim Peters482c0212000-09-26 06:33:09 +00002080- Several of the internal Unicode tables are much smaller now, and
2081 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002082
Jeremy Hylton97693b02000-09-26 17:42:51 +00002083- In the garbage collector: Fixed bug in collection of tuples. Fixed
2084 bug that caused some instances to be removed from the container set
2085 while they were still live. Fixed parsing in gc.set_debug() for
2086 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002087
2088- Fixed refcount problem in instance deallocation that only occurred
2089 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2090
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002091- On Windows, getpythonregpath is now protected against null data in
2092 registry key.
2093
2094- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002095 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002096
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002097
Jeremy Hylton1b618592000-09-26 05:32:36 +00002098Build and platform-specific issues
2099
2100- Better support of GNU Pth via --with-pth configure option.
2101
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002102- Python/C API now properly exposed to dynamically-loaded extension
2103 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002104
2105- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2106 Don't define MS_SYNC to be zero when it is undefined. Added missing
2107 prototypes in posixmodule.c.
2108
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002109- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002110 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002111
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002112- Fix largefile support on older NetBSD systems and OpenBSD by adding
2113 define for TELL64.
2114
2115
2116Tools and other miscellany
2117
2118- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2119
2120- freeze: The modulefinder now works with 2.0 opcodes.
2121
Tim Petersa3a3a032000-11-30 05:22:44 +00002122- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002123 Move hackery of sys.argv until after the Tk instance has been
2124 created, which allows the application-specific Tkinter
2125 initialization to be executed if present; also pass an explicit
2126 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002127
Jeremy Hylton1b618592000-09-26 05:32:36 +00002128
2129What's new in 2.0 beta 1?
2130=========================
2131
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002132Source Incompatibilities
2133------------------------
2134
2135None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2136such as single-argument append(), connect() and bind(), and changes to
2137str(long) and repr(float).
2138
2139
2140Binary Incompatibilities
2141------------------------
2142
2143- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2144with Python 2.0; these extensions will have to be rebuilt for Python
21452.0.
2146
2147- On Windows, attempting to import a third party extension built for
2148Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2149can do about this. Check your PYTHONPATH environment variable!
2150
2151- Python bytecode files (*.pyc and *.pyo) are not compatible between
2152releases.
2153
2154
2155Overview of Changes Since 1.6
2156-----------------------------
2157
2158There are many new modules (including brand new XML support through
2159the xml package, and i18n support through the gettext module); a list
2160of all new modules is included below. Lots of bugs have been fixed.
2161
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002162The process for making major new changes to the language has changed
2163since Python 1.6. Enhancements must now be documented by a Python
2164Enhancement Proposal (PEP) before they can be accepted.
2165
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002166There are several important syntax enhancements, described in more
2167detail below:
2168
2169 - Augmented assignment, e.g. x += 1
2170
2171 - List comprehensions, e.g. [x**2 for x in range(10)]
2172
2173 - Extended import statement, e.g. import Module as Name
2174
2175 - Extended print statement, e.g. print >> file, "Hello"
2176
2177Other important changes:
2178
2179 - Optional collection of cyclical garbage
2180
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002181Python Enhancement Proposal (PEP)
2182---------------------------------
2183
2184PEP stands for Python Enhancement Proposal. A PEP is a design
2185document providing information to the Python community, or describing
2186a new feature for Python. The PEP should provide a concise technical
2187specification of the feature and a rationale for the feature.
2188
2189We intend PEPs to be the primary mechanisms for proposing new
2190features, for collecting community input on an issue, and for
2191documenting the design decisions that have gone into Python. The PEP
2192author is responsible for building consensus within the community and
2193documenting dissenting opinions.
2194
2195The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002196
2197Augmented Assignment
2198--------------------
2199
2200This must have been the most-requested feature of the past years!
2201Eleven new assignment operators were added:
2202
Guido van Rossume905e952000-09-05 12:42:46 +00002203 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002204
2205For example,
2206
2207 A += B
2208
2209is similar to
2210
2211 A = A + B
2212
2213except that A is evaluated only once (relevant when A is something
2214like dict[index].attr).
2215
2216However, if A is a mutable object, A may be modified in place. Thus,
2217if A is a number or a string, A += B has the same effect as A = A+B
2218(except A is only evaluated once); but if a is a list, A += B has the
2219same effect as A.extend(B)!
2220
2221Classes and built-in object types can override the new operators in
2222order to implement the in-place behavior; the not-in-place behavior is
2223used automatically as a fallback when an object doesn't implement the
2224in-place behavior. For classes, the method name is derived from the
2225method name for the corresponding not-in-place operator by inserting
2226an 'i' in front of the name, e.g. __iadd__ implements in-place
2227__add__.
2228
2229Augmented assignment was implemented by Thomas Wouters.
2230
2231
2232List Comprehensions
2233-------------------
2234
2235This is a flexible new notation for lists whose elements are computed
2236from another list (or lists). The simplest form is:
2237
2238 [<expression> for <variable> in <sequence>]
2239
Guido van Rossum56db0952000-09-06 23:34:25 +00002240For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002241This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002242
2243You can also add a condition:
2244
2245 [<expression> for <variable> in <sequence> if <condition>]
2246
2247For example, [w for w in words if w == w.lower()] would yield the list
2248of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002249than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002250
2251You can also have nested for loops and more than one 'if' clause. For
2252example, here's a function that flattens a sequence of sequences::
2253
2254 def flatten(seq):
2255 return [x for subseq in seq for x in subseq]
2256
2257 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2258
2259This prints
2260
2261 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2262
2263List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002264Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002265
2266
2267Extended Import Statement
2268-------------------------
2269
2270Many people have asked for a way to import a module under a different
2271name. This can be accomplished like this:
2272
2273 import foo
2274 bar = foo
2275 del foo
2276
2277but this common idiom gets old quickly. A simple extension of the
2278import statement now allows this to be written as follows:
2279
2280 import foo as bar
2281
2282There's also a variant for 'from ... import':
2283
2284 from foo import bar as spam
2285
2286This also works with packages; e.g. you can write this:
2287
2288 import test.regrtest as regrtest
2289
2290Note that 'as' is not a new keyword -- it is recognized only in this
2291context (this is only possible because the syntax for the import
2292statement doesn't involve expressions).
2293
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002294Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002295
2296
2297Extended Print Statement
2298------------------------
2299
2300Easily the most controversial new feature, this extension to the print
2301statement adds an option to make the output go to a different file
2302than the default sys.stdout.
2303
2304For example, to write an error message to sys.stderr, you can now
2305write:
2306
2307 print >> sys.stderr, "Error: bad dog!"
2308
2309As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002310evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002311
2312 print >> None, "Hello world"
2313
2314is equivalent to
2315
2316 print "Hello world"
2317
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002318Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002319
2320
2321Optional Collection of Cyclical Garbage
2322---------------------------------------
2323
2324Python is now equipped with a garbage collector that can hunt down
2325cyclical references between Python objects. It's no replacement for
2326reference counting; in fact, it depends on the reference counts being
2327correct, and decides that a set of objects belong to a cycle if all
2328their reference counts can be accounted for from their references to
2329each other. This devious scheme was first proposed by Eric Tiedemann,
2330and brought to implementation by Neil Schemenauer.
2331
2332There's a module "gc" that lets you control some parameters of the
2333garbage collection. There's also an option to the configure script
2334that lets you enable or disable the garbage collection. In 2.0b1,
2335it's on by default, so that we (hopefully) can collect decent user
2336experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002337performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002338off by default in the final 2.0 release.
2339
2340
2341Smaller Changes
2342---------------
2343
2344A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2345map(None, seq1, seq2, ...) when the sequences have the same length;
2346i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2347the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002348zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002349
2350sys.version_info is a tuple (major, minor, micro, level, serial).
2351
2352Dictionaries have an odd new method, setdefault(key, default).
2353dict.setdefault(key, default) returns dict[key] if it exists; if not,
2354it sets dict[key] to default and returns that value. Thus:
2355
2356 dict.setdefault(key, []).append(item)
2357
2358does the same work as this common idiom:
2359
2360 if not dict.has_key(key):
2361 dict[key] = []
2362 dict[key].append(item)
2363
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002364There are two new variants of SyntaxError that are raised for
2365indentation-related errors: IndentationError and TabError.
2366
2367Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2368escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002369
2370The limits on the size of expressions and file in Python source code
2371have been raised from 2**16 to 2**32. Previous versions of Python
2372were limited because the maximum argument size the Python VM accepted
2373was 2**16. This limited the size of object constructor expressions,
2374e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2375limit was raised thanks to a patch by Charles Waldman that effectively
2376fixes the problem. It is now much more likely that you will be
2377limited by available memory than by an arbitrary limit in Python.
2378
2379The interpreter's maximum recursion depth can be modified by Python
2380programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2381limit is the maximum number of recursive calls that can be made by
2382Python code. The limit exists to prevent infinite recursion from
2383overflowing the C stack and causing a core dump. The default value is
23841000. The maximum safe value for a particular platform can be found
2385by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002386
2387New Modules and Packages
2388------------------------
2389
2390atexit - for registering functions to be called when Python exits.
2391
2392imputil - Greg Stein's alternative API for writing custom import
2393hooks.
2394
2395pyexpat - an interface to the Expat XML parser, contributed by Paul
2396Prescod.
2397
2398xml - a new package with XML support code organized (so far) in three
2399subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2400would fill a volume. There's a special feature whereby a
2401user-installed package named _xmlplus overrides the standard
2402xmlpackage; this is intended to give the XML SIG a hook to distribute
2403backwards-compatible updates to the standard xml package.
2404
2405webbrowser - a platform-independent API to launch a web browser.
2406
2407
Guido van Rossume905e952000-09-05 12:42:46 +00002408Changed Modules
2409---------------
2410
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002411array -- new methods for array objects: count, extend, index, pop, and
2412remove
2413
2414binascii -- new functions b2a_hex and a2b_hex that convert between
2415binary data and its hex representation
2416
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002417calendar -- Many new functions that support features including control
2418over which day of the week is the first day, returning strings instead
2419of printing them. Also new symbolic constants for days of week,
2420e.g. MONDAY, ..., SUNDAY.
2421
2422cgi -- FieldStorage objects have a getvalue method that works like a
2423dictionary's get method and returns the value attribute of the object.
2424
2425ConfigParser -- The parser object has new methods has_option,
2426remove_section, remove_option, set, and write. They allow the module
2427to be used for writing config files as well as reading them.
2428
2429ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002430optionally support the RFC 959 REST command.
2431
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002432gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002433
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002434httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2435the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002436
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002437locale -- implement getdefaultlocale for Win32 and Macintosh
2438
2439marshal -- no longer dumps core when marshaling deeply nested or
2440recursive data structures
2441
2442os -- new functions isatty, seteuid, setegid, setreuid, setregid
2443
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002444os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2445support under Unix.
2446
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002447os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002448
2449os.path -- fix semantics of os.path.commonprefix
2450
2451smtplib -- support for sending very long messages
2452
2453socket -- new function getfqdn()
2454
2455readline -- new functions to read, write and truncate history files.
2456The readline section of the library reference manual contains an
2457example.
2458
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002459select -- add interface to poll system call
2460
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002461shutil -- new copyfileobj function
2462
2463SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2464HTTP server.
2465
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002466Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002467
2468urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002469e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002470
2471whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002472
2473
2474Obsolete Modules
2475----------------
2476
2477None. However note that 1.6 made a whole slew of modules obsolete:
2478stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2479poly, zmod, strop, util, whatsound.
2480
2481
2482Changed, New, Obsolete Tools
2483----------------------------
2484
Tim Peters8b092332000-09-05 20:15:25 +00002485None.
Guido van Rossume905e952000-09-05 12:42:46 +00002486
2487
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002488C-level Changes
2489---------------
2490
2491Several cleanup jobs were carried out throughout the source code.
2492
2493All C code was converted to ANSI C; we got rid of all uses of the
2494Py_PROTO() macro, which makes the header files a lot more readable.
2495
2496Most of the portability hacks were moved to a new header file,
2497pyport.h; several other new header files were added and some old
2498header files were removed, in an attempt to create a more rational set
2499of header files. (Few of these ever need to be included explicitly;
2500they are all included by Python.h.)
2501
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002502Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002503and Win64, especially for the new Intel Itanium processor. Mick also
2504added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002505
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002506The C APIs to return an object's size have been update to consistently
2507use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2508previous versions, the abstract interfaces used PyXXX_Length and the
2509concrete interfaces used PyXXX_Size. The old names,
2510e.g. PyObject_Length, are still available for backwards compatibility
2511at the API level, but are deprecated.
2512
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002513The PyOS_CheckStack function has been implemented on Windows by
2514Fredrik Lundh. It prevents Python from failing with a stack overflow
2515on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002516
2517The GC changes resulted in creation of two new slots on object,
2518tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002519the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002520
2521The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002522C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002523
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002524PyErr_Format has been updated to automatically calculate the size of
2525the buffer needed to hold the formatted result string. This change
2526prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002527
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002528New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002529
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002530PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2531that are the same as their non-Ex counterparts except they take an
2532extra flag argument that tells them to close the file when done.
2533
2534XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002535
Tim Peters8b092332000-09-05 20:15:25 +00002536
2537Windows Changes
2538---------------
2539
2540New popen2/popen3/peopen4 in os module (see Changed Modules above).
2541
2542os.popen is much more usable on Windows 95 and 98. See Microsoft
2543Knowledge Base article Q150956. The Win9x workaround described there
2544is implemented by the new w9xpopen.exe helper in the root of your
2545Python installation. Note that Python uses this internally; it is not
2546a standalone program.
2547
2548Administrator privileges are no longer required to install Python
2549on Windows NT or Windows 2000. If you have administrator privileges,
2550Python's registry info will be written under HKEY_LOCAL_MACHINE.
2551Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002552under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002553uses of Python, but will prevent some advanced uses from working
2554(for example, running a Python script as an NT service, or possibly
2555from CGI).
2556
2557[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2558installer; instead, it installs the needed Tcl/Tk files directly in the
2559Python directory. If you already have a Tcl/Tk installation, this
2560wastes some disk space (about 4 Megs) but avoids problems with
2561conflicting Tcl/Tk installations, and makes it much easier for Python
2562to ensure that Tcl/Tk can find all its files.
2563
2564[This was new in 1.6] The Windows installer now installs by default in
2565\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2566
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002567
2568Updates to the changes between 1.5.2 and 1.6
2569--------------------------------------------
2570
2571The 1.6 NEWS file can't be changed after the release is done, so here
2572is some late-breaking news:
2573
2574New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2575and changes to getlocale() and setlocale().
2576
2577The new module is now enabled per default.
2578
2579It is not true that the encodings codecs cannot be used for normal
2580strings: the string.encode() (which is also present on 8-bit strings
2581!) allows using them for 8-bit strings too, e.g. to convert files from
2582cp1252 (Windows) to latin-1 or vice-versa.
2583
2584Japanese codecs are available from Tamito KAJIYAMA:
2585http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2586
2587
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002588======================================================================