blob: 1d0e12c30fefe0ee2d9c2bfa2bbec5511c25f7fa [file] [log] [blame]
Tim Petersb07352e2001-09-08 01:25:47 +00001What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +00002Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +00003===========================
4
Guido van Rossum808eea72001-09-25 04:15:41 +00005Type/class unification and new-style classes
6
7- pydoc and inspect are now aware of new-style classes;
8 e.g. help(list) at the interactive prompt now shows proper
9 documentation for all operations on list objects.
10
11- Applications using Jim Fulton's ExtensionClass module can now safely
12 be used with Python 2.2. In particular, Zope 2.4.1 now works with
13 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
14 examples also work again. It is hoped that Gtk and Boost also work
15 with 2.2a4 and beyond. (If you can confirm this, please write
16 webmaster@python.org; if there are still problems, please open a bug
17 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +000018
Tim Peters66c1a522001-09-24 21:17:50 +000019- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
20 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
21 in the constructed property object. fget, fset and fdel weren't
22 discoverable from Python in 2.2a3. __doc__ is new, and allows to
23 associate a docstring with a property.
24
Guido van Rossum808eea72001-09-25 04:15:41 +000025- Comparison overloading is now more completely implemented. For
26 example, a str subclass instance can properly be compared to a str
27 instance, and it can properly overload comparison. Ditto for most
28 other built-in object types.
29
30- The repr() of new-style classes has changed; instead of <type
31 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
32 *except* for built-in types, which are still rendered as <type
33 'Foo'> (to avoid upsetting existing code that might parse or
34 otherwise rely on repr() of certain type objects).
35
36- The repr() of new-style objects is now always <Foo object at XXX>;
37 previously, it was sometimes <Foo instance at XXX>.
38
39- For new-style classes, what was previously called __getattr__ is now
40 called __getattribute__. This method, if defined, is called for
41 *every* attribute access. A new __getattr__ hook mor similar to the
42 one in classic classes is defined which is called only if regular
43 attribute access raises AttributeError; to catch *all* attribute
44 access, you can use __getattribute__ (for new-style classes). If
45 both are defined, __getattribute__ is called first, and if it raises
46 AttributeError, __getattr__ is called.
47
48- The __class__ attribute of new-style objects can be assigned to.
49 The new class must have the same C-level object layout as the old
50 class.
51
52- The builtin file type can be subclassed now. In the usual pattern,
53 "file" is the name of the builtin type, and file() is a new builtin
54 constructor, with the same signature as the builtin open() function.
55 file() is now the preferred way to open a file.
56
57- Previously, __new__ would only see sequential arguments passed to
58 the type in a constructor call; __init__ would see both sequential
59 and keyword arguments. This made no sense whatsoever any more, so
60 now both __new__ and __init__ see all arguments.
61
62- Previously, hash() applied to an instance of a subclass of str or
63 unicode always returned 0. This has been repaired.
64
65- Previously, an operation on an instance of a subclass of an
66 immutable type (int, long, float, complex, tuple, str, unicode),
67 where the subtype didn't override the operation (and so the
68 operation was handled by the builtin type), could return that
69 instance instead a value of the base type. For example, if s was of
70 a str sublass type, s[:] returned s as-is. Now it returns a str
71 with the same value as s.
72
Barry Warsaw86fbaf82001-09-28 15:26:12 +000073- Provisional support for pickling new-style objects has been added.
74
Guido van Rossum808eea72001-09-25 04:15:41 +000075Core
76
Tim Peters2c9aa5e2001-09-23 04:06:05 +000077- file.writelines() now accepts any iterable object producing strings.
78
Marc-André Lemburgaefd7662001-09-20 12:59:37 +000079- PyUnicode_FromEncodedObject() now works very much like
80 PyObject_Str(obj) in that it tries to use __str__/tp_str
81 on the object if the object is not a string or buffer. This
82 makes unicode() behave like str() when applied to non-string/buffer
83 objects.
84
Martin v. Löwis2777c022001-09-19 13:47:32 +000085- PyFile_WriteObject now passes Unicode object to the file's write
86 method. As a result, all file-like object which may be the target
87 of a print statement must support Unicode objects, i.e. they must
88 at least convert them into ASCII strings.
89
Guido van Rossum624c8af2001-09-18 15:21:04 +000090- Thread scheduling on Solaris should be improved; it is no longer
91 necessary to insert a small sleep at the start of a thread in order
92 to let other runnable threads be scheduled.
93
Tim Petersb07352e2001-09-08 01:25:47 +000094Library
95
Marc-André Lemburgbf990172001-09-27 14:17:33 +000096- StringIO.StringIO instances and cStringIO.StringIO instances support
97 read character buffer compatible objects for their .write() methods.
98 These objects are converted to strings and then handled as such
99 by the instances.
100
Barry Warsaw2f600732001-09-24 04:28:10 +0000101- The "email" package has been added. This is basically a port of the
102 mimelib package <http://sf.net/projects/mimelib> with API changes
103 and some implementations updated to use iterators and generators.
104
Tim Peters8a9c2842001-09-22 21:30:22 +0000105- difflib.ndiff() and difflib.Differ.compare() are generators now. This
106 restores the ability of Tools/scripts/ndiff.py to start producing output
107 before the entire comparison is complete.
108
Barry Warsaw58b072d2001-09-22 04:44:21 +0000109- StringIO.StringIO instances and cStringIO.StringIO instances support
110 iteration just like file objects (i.e. their .readline() method is
111 called for each iteration until it returns an empty string).
112
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000113- The codecs module has grown four new helper APIs to access
114 builtin codecs: getencoder(), getdecoder(), getreader(),
115 getwriter().
116
Guido van Rossum624c8af2001-09-18 15:21:04 +0000117- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
118 simplifies writing XML RPC servers.
119
120- os.path.realpath(): a new function that returns the absoute pathname
121 after interpretation of symbolic links. On non-Unix systems, this
122 is an alias for os.path.abspath().
123
Tim Peters16a77ad2001-09-08 04:00:12 +0000124- operator.indexOf() (PySequence_Index() in the C API) now works with any
125 iterable object.
126
Guido van Rossum624c8af2001-09-18 15:21:04 +0000127- smtplib now supports various authentication and security features of
128 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000129
Guido van Rossum624c8af2001-09-18 15:21:04 +0000130- hmac: a new module implementing keyed hashing for message
131 authentication.
132
133- mimetypes now recognizes more extensions and file types. At the
134 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000135
Guido van Rossum624c8af2001-09-18 15:21:04 +0000136- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000137 Python 2.2 bytecode generation. It has also been promoted from a
138 Tool to a standard library package. (Tools/compiler still exists as
139 a sample driver.)
140
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000141Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000142
Tim Petersb07352e2001-09-08 01:25:47 +0000143Build
144
Guido van Rossum624c8af2001-09-18 15:21:04 +0000145- Large file support (LFS) is now automatic when the platform supports
146 it; no more manual configuration tweaks are needed. On Linux, at
147 least, it's possible to have a system whose C library supports large
148 files but whose kernel doesn't; in this case, large file support is
149 still enabled but doesn't do you any good unless you upgrade your
150 kernel or share your Python executable with another system whose
151 kernel has large file support.
152
153- The configure script now supplies plausible defaults in a
154 cross-compilation environment. This doesn't mean that the supplied
155 values are always correct, or that cross-compilation now works
156 flawlessly -- but it's a first step (and it shuts up most of
157 autoconf's warnings about AC_TRY_RUN).
158
159- The Unix build is now a bit less chatty, courtesy of the parser
160 generator. The build is completely silent (except for errors) when
161 using "make -s", thanks to a -q option to setup.py.
162
Tim Petersb07352e2001-09-08 01:25:47 +0000163C API
164
Guido van Rossum624c8af2001-09-18 15:21:04 +0000165- The "structmember" API now supports some new flag bits to deny read
166 and/or write access to attributes in restricted execution mode.
167
Tim Petersb07352e2001-09-08 01:25:47 +0000168New platforms
169
Guido van Rossum624c8af2001-09-18 15:21:04 +0000170- Compaq's iPAQ handheld, running the "familiar" Linux distribution
171 (http://familiar.handhelds.org).
172
Tim Petersb07352e2001-09-08 01:25:47 +0000173Tests
174
Tim Peters8a9c2842001-09-22 21:30:22 +0000175- The "classic" standard tests, which work by comparing stdout to
176 an expected-output file under Lib/test/output/, no longer stop at
177 the first mismatch. Instead the test is run to completion, and a
178 variant of ndiff-style comparison is used to report all differences.
179 This is much easier to understand than the previous style of reporting.
180
181- The unittest-based standard tests now use regrtest's test_main()
182 convention, instead of running as a side-effect of merely being
183 imported. This allows these tests to be run in more natural and
184 flexible ways as unittests, outside the regrtest framework.
185
186- regrtest.py is much better integrated with unittest and doctest now,
187 especially in regard to reporting errors.
188
Tim Petersb07352e2001-09-08 01:25:47 +0000189Windows
190
Guido van Rossum624c8af2001-09-18 15:21:04 +0000191- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000192 that support it (NTFS under Windows 2000). See "What's New in
193 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000194
Tim Petersb07352e2001-09-08 01:25:47 +0000195
Tim Petersedc99312001-08-22 21:36:50 +0000196What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000197Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000198===========================
199
200Core
201
Tim Peters9fffa3e2001-09-04 05:14:19 +0000202- Conversion of long to float now raises OverflowError if the long is too
203 big to represent as a C double.
204
Tim Peters32f453e2001-09-03 08:35:41 +0000205- The 3-argument builtin pow() no longer allows a third non-None argument
206 if either of the first two arguments is a float, or if both are of
207 integer types and the second argument is negative (in which latter case
208 the arguments are converted to float, so this is really the same
209 restriction).
210
Tim Peters5d2b77c2001-09-03 05:47:38 +0000211- The builtin dir() now returns more information, and sometimes much
212 more, generally naming all attributes of an object, and all attributes
213 reachable from the object via its class, and from its class's base
214 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
215 an empty list. In 2.2a3,
216
217 >>> dir([])
218 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
219 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
220 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
221 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
222 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
223 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
224 'reverse', 'sort']
225
226 dir(module) continues to return only the module's attributes, though.
227
Tim Petersbdee63f2001-09-02 03:40:59 +0000228- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000229 than raising OverflowError. This is a partial implementation of PEP
230 237. You can use -Wdefault::OverflowWarning to enable a warning for
231 this situation, and -Werror::OverflowWarning to revert to the old
232 OverflowError exception.
233
Guido van Rossum61c345f2001-09-04 03:26:15 +0000234- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000235 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000236 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
237 -Qold, meaning the / operator has its classic meaning and no
238 warnings are issued. Using -Qwarn issues a run-time warning about
239 all uses of classic division for int and long arguments; -Qwarnall
240 also warns about classic division for float and complex arguments
241 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
242 new division by default, but only in the __main__ module. You can
243 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
244 __main__ module new division, and warns about classic division
245 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000246
Tim Petersbdee63f2001-09-02 03:40:59 +0000247- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000248 long, float, str, unicode, and tuple. (The types complex, list and
249 dictionary can also be subclassed; this was introduced earlier.)
250 Note that restrictions apply when subclassing immutable built-in
251 types: you can only affect the value of the instance by overloading
252 __new__. You can add mutable attributes, and the subclass instances
253 will have a __dict__ attribute, but you cannot change the "value"
254 (as implemented by the base class) of an immutable subclass instance
255 once it is created.
256
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000257- The dictionary constructor now takes an optional argument, a
258 mapping-like object, and initializes the dictionary from its
259 (key, value) pairs.
260
Tim Petersbdee63f2001-09-02 03:40:59 +0000261- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000262 "cooperative super calls" in a multiple inheritance setting. For an
263 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
264
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000265- A new built-in type, property, has been added. This enables the
266 creation of "properties". These are attributes implemented by
267 getter and setter functions (or only one of these for read-only or
268 write-only attributes), without the need to override __getattr__.
269 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000270
Tim Petersbdee63f2001-09-02 03:40:59 +0000271- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000272 liberalized, to allow leading zeroes. Examples of literals now
273 legal that were SyntaxErrors before:
274
275 00.0 0e3 0100j 07.5 00000000000000000008.
276
Tim Petersbdee63f2001-09-02 03:40:59 +0000277- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000278 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
279
Tim Petersedc99312001-08-22 21:36:50 +0000280Library
281
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000282- telnetlib includes symbolic names for the options, and support for
283 setting an option negotiation callback.
284
Tim Petersa40c7932001-09-05 22:36:56 +0000285- The new C standard no longer requires that math libraries set errno to
286 ERANGE on overflow. For platform libraries that exploit this new
287 freedom, Python's overflow-checking was wholly broken. A new overflow-
288 checking scheme attempts to repair that, but may not be reliable on all
289 platforms (C doesn't seem to provide anything both useful and portable
290 in this area anymore).
291
Martin v. Löwis44f86962001-09-05 13:44:54 +0000292- Asynchronous timeout actions are available through the new class
293 threading.Timer.
294
Tim Peters78526162001-09-05 00:53:45 +0000295- math.log and math.log10 now return sensible results for even huge
296 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
297
Tim Petersbdee63f2001-09-02 03:40:59 +0000298- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000299 currently held. See the docs for the imp module.
300
Tim Petersbdee63f2001-09-02 03:40:59 +0000301- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000302 dumps containing ints written on platforms where Python ints are 8 bytes.
303 When read on a box where Python ints are 4 bytes, such values are
304 converted to Python longs.
305
Tim Petersbdee63f2001-09-02 03:40:59 +0000306- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000307 code objects is no longer allowed. This plugs a security hole.
308
Steve Purcell6091cd62001-09-06 16:05:17 +0000309- unittest.TestResult instances no longer store references to tracebacks
310 generated by test failures. This prevents unexpected dangling references
311 to objects that should be garbage collected between tests.
312
Tim Petersedc99312001-08-22 21:36:50 +0000313Tools
314
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000315- Tools/scripts/fixdiv.py has been added which can be used to fix
316 division operators as per PEP 238.
317
Tim Petersedc99312001-08-22 21:36:50 +0000318Build
319
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000320- If you are an adventurous person using Mac OS X you may want to look at
321 Mac/OSX. There is a Makefile there that will build Python as a real Mac
322 application, which can be used for experimenting with Carbon or Cocoa.
323 Discussion of this on pythonmac-sig, please.
324
Tim Peters7eea37e2001-09-04 22:08:56 +0000325C API
326
327- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000328
Tim Peters9fffa3e2001-09-04 05:14:19 +0000329- Note that PyLong_AsDouble can fail! This has always been true, but no
330 callers checked for it. It's more likely to fail now, because overflow
331 errors are properly detected now. The proper way to check:
332
333 double x = PyLong_AsDouble(some_long_object);
334 if (x == -1.0 && PyErr_Occurred()) {
335 /* The conversion failed. */
336 }
337
Tim Petersbdee63f2001-09-02 03:40:59 +0000338- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000339 compile but will not participate in GC. To upgrade an extension
340 module:
341
342 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000343
Neil Schemenauer4042c692001-08-30 15:38:01 +0000344 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
345 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000346
Neil Schemenauer4042c692001-08-30 15:38:01 +0000347 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
348 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000349
Neil Schemenauer4042c692001-08-30 15:38:01 +0000350 - remove PyGC_HEAD_SIZE from object size calculations
351
352 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
353
Tim Petersbdee63f2001-09-02 03:40:59 +0000354- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000355 These can be used safely to construct string objects from a
356 sprintf-style format string (similar to the format string supported
357 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000358
Tim Petersedc99312001-08-22 21:36:50 +0000359New platforms
360
Tim Petersb7da0902001-09-02 23:01:43 +0000361- Stephen Hansen contributed patches sufficient to get a clean compile
362 under Borland C (Windows), but he reports problems running it and ran
363 out of time to complete the port. Volunteers? Expect a MemoryError
364 when importing the types module; this is probably shallow, and
365 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000366
Tim Petersedc99312001-08-22 21:36:50 +0000367Tests
368
369Windows
370
Tim Peters6e13a562001-09-06 00:32:15 +0000371- Large file support is now enabled on Win32 platforms as well as on
372 Win64. This means that, for example, you can use f.tell() and f.seek()
373 to manipulate files larger than 2 gigabytes (provided you have enough
374 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000375 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
376 filesize limit, and large file support makes no difference there.
377 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
378 NTFS has no practical limit on file size, and files of any size can be
379 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000380
Tim Petersbdee63f2001-09-02 03:40:59 +0000381- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000382 points to command.com (patch from Brian Quinlan).
383
Tim Petersedc99312001-08-22 21:36:50 +0000384
Tim Peters20f51a72001-07-21 02:31:40 +0000385What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000386Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000387===========================
388
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000389Build
390
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000391- Tim Peters developed a brand new Windows installer using Wise 8.1,
392 generously donated to us by Wise Solutions.
393
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000394- configure supports a new option --enable-unicode, with the values
395 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
396 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000397
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000398- A new configure option --enable-framework builds a Mac OS X framework,
399 which "make frameworkinstall" will install. This provides a starting
400 point for more mac-like functionality, join pythonmac-sig@python.org
401 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000402
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000403- The NeXT platform is no longer supported.
404
405- The `new' module is now statically linked.
406
Tim Peters0afb6092001-08-15 06:06:44 +0000407Tools
408
409- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000410 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000411 the module docstring for details.
412
Tim Peters20f51a72001-07-21 02:31:40 +0000413Tests
414
Tim Peters5e824c32001-08-12 22:25:01 +0000415- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000416 platforms, allowing to give clearer test result output. regrtest
417 also has optional --use/-u switch to run normally disabled tests
418 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000419
Tim Peters20f51a72001-07-21 02:31:40 +0000420- Several new tests in the standard test suite, with special thanks to
421 Nick Mathewson.
422
423Core
424
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000425- The floor division operator // has been added as outlined in PEP
426 238. The / operator still provides classic division (and will until
427 Python 3.0) unless "from __future__ import division" is included, in
428 which case the / operator will provide true division. The operator
429 module provides truediv() and floordiv() functions. Augmented
430 assignment variants are included, as are the equivalent overloadable
431 methods and C API methods. See the PEP for a full discussion:
432 <http://python.sf.net/peps/pep-0238.html>
433
Tim Peters6cd6a822001-08-17 22:11:27 +0000434- Future statements are now effective in simulated interactive shells
435 (like IDLE). This should "just work" by magic, but read Michael
436 Hudson's "Future statements in simulated shells" PEP 264 for full
437 details: <http://python.sf.net/peps/pep-0264.html>.
438
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000439- The type/class unification (PEP 252-253) was integrated into the
440 trunk and is not so tentative any more (the exact specification of
441 some features is still tentative). A lot of work has done on fixing
442 bugs and adding robustness and features (performance still has to
443 come a long way).
444
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000445- Warnings about a mismatch in the Python API during extension import
446 now use the Python warning framework (which makes it possible to
447 write filters for these warnings).
448
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000449- A function's __dict__ (aka func_dict) will now always be a
450 dictionary. It used to be possible to delete it or set it to None,
451 but now both actions raise TypeErrors. It is still legal to set it
452 to a dictionary object. Getting func.__dict__ before any attributes
453 have been assigned now returns an empty dictionary instead of None.
454
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000455- A new command line option, -E, was added which disables the use of
456 all environment variables, or at least those that are specifically
457 significant to Python. Usually those have a name starting with
458 "PYTHON". This was used to fix a problem where the tests fail if
459 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
460 older distribution.
461
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000462Library
463
Tim Peters5e824c32001-08-12 22:25:01 +0000464- New class Differ and new functions ndiff() and restore() in difflib.py.
465 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000466 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000467
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000468- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
469 value using the minimal quoting required for the value; more
470 reliable than using xml.sax.saxutils.escape() for attribute values.
471
472- Readline completion support for cmd.Cmd was added.
473
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000474- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
475
476- Added function threading.BoundedSemaphore()
477
478- Added Ka-Ping Yee's cgitb.py module.
479
480- The `new' module now exposes the CO_xxx flags.
481
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000482New platforms
483
484C API
485
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000486- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
487 which provide a cross-platform implementations for the
488 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
489 the standard sprintf() and vsprintf() C lib APIs, these versions
490 apply bounds checking on the used buffer which enhances protection
491 against buffer overruns.
492
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000493- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000494 and extensions using different Unicode widths is rendered next to
495 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000496 will result in an ImportError. Unicode extensions writers must make
497 sure to check the Unicode width compatibility in their extensions by
498 using at least one of the mangled Unicode APIs in the extension.
499
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000500- Two new flags METH_NOARGS and METH_O are available in method definition
501 tables to simplify implementation of methods with no arguments and a
502 single untyped argument. Calling such methods is more efficient than
503 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
504 deprecated.
505
Tim Petersc1731372001-08-04 08:12:36 +0000506Windows
507
508- "import module" now compiles module.pyw if it exists and nothing else
509 relevant is found.
510
Tim Peters20f51a72001-07-21 02:31:40 +0000511
Guido van Rossum55a78992001-07-17 17:22:32 +0000512What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +0000513===========================
514
515Core
Tim Petersa814db52001-05-14 07:05:58 +0000516
Tim Peters6d6c1a32001-08-02 04:15:00 +0000517- TENTATIVELY, a large amount of code implementing much of what's
518 described in PEP 252 (Making Types Look More Like Classes) and PEP
519 253 (Subtyping Built-in Types) was added. This will be released
520 with Python 2.2a1. Documentation will be provided separately
521 through http://www.python.org/2.2/. The purpose of releasing this
522 with Python 2.2a1 is to test backwards compatibility. It is
523 possible, though not likely, that a decision is made not to release
524 this code as part of 2.2 final, if any serious backwards
525 incompapatibilities are found during alpha testing that cannot be
526 repaired.
527
Guido van Rossum55a78992001-07-17 17:22:32 +0000528- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000529 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000530 more 'yield' statements. See PEP 255. Since this adds a new
531 keyword to the language, this feature must be enabled by including a
532 future statement: "from __future__ import generators" (see PEP 236).
533 Generators will become a standard feature in a future release
534 (probably 2.3). Without this future statement, 'yield' remains an
535 ordinary identifier, but a warning is issued each time it is used.
536 (These warnings currently don't conform to the warnings framework of
537 PEP 230; we intend to fix this in 2.2a2.)
538
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000539- The UTF-16 codec was modified to be more RFC compliant. It will now
540 only remove BOM characters at the start of the string and then
541 only if running in native mode (UTF-16-LE and -BE won't remove a
542 leading BMO character).
543
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000544- Strings now have a new method .decode() to complement the already
545 existing .encode() method. These two methods provide direct access
546 to the corresponding decoders and encoders of the registered codecs.
547
548 To enhance the usability of the .encode() method, the special
549 casing of Unicode object return values was dropped (Unicode objects
550 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000551
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000552 Both methods will now return whatever the codec in charge of the
553 requested encoding returns as object, e.g. Unicode codecs will
554 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
555 will return u"äöü"). This enables codec writer to create codecs
556 for various simple to use conversions.
557
558 New codecs were added to demonstrate these new features (the .encode()
559 and .decode() columns indicate the type of the returned objects):
560
561 Name | .encode() | .decode() | Description
562 ----------------------------------------------------------------------
563 uu | string | string | UU codec (e.g. for email)
564 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000565 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000566 zlib | string | string | zlib compression
567 hex | string | string | 2-byte hex codec
568 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
569
Mark Hammond2a0af792001-05-14 03:09:36 +0000570- Some operating systems now support the concept of a default Unicode
571 encoding for file system operations. Notably, Windows supports 'mbcs'
572 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000573 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000574 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000575
576 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000577 functions that return filenames (such as os.listdir()) to return Python
578 string objects pre-encoded using the default file system encoding for
579 the platform. As this encoding is likely to be different from Python's
580 default encoding, converting this name to a Unicode object before passing
581 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000582 would attempt to use its default encoding (generally ASCII) rather than
583 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000584
Tim Petersa814db52001-05-14 07:05:58 +0000585 In general, this change simply removes surprises when working with
586 Unicode and the file system, making these operations work as you expect,
587 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000588 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000589
Tim Peters61dff2b2001-05-08 15:43:37 +0000590- Float (and complex) literals in source code were evaluated to full
591 precision only when running from a .py file; the same code loaded from a
592 .pyc (or .pyo) file could suffer numeric differences starting at about the
593 12th significant decimal digit. For example, on a machine with IEEE-754
594 floating arithmetic,
595
596 x = 9007199254740992.0
597 print long(x)
598
599 printed 9007199254740992 if run directly from .py, but 9007199254740000
600 if from a compiled (.pyc or .pyo) file. This was due to marshal using
601 str(float) instead of repr(float) when building code objects. marshal
602 now uses repr(float) instead, which should reproduce floats to full
603 machine precision (assuming the platform C float<->string I/O conversion
604 functions are of good quality).
605
606 This may cause floating-point results to change in some cases, and
607 usually for the better, but may also cause numerically unstable
608 algorithms to break.
609
Tim Peters2f228e72001-05-13 00:19:31 +0000610- The implementation of dicts suffers fewer collisions, which has speed
611 benefits. However, the order in which dict entries appear in dict.keys(),
612 dict.values() and dict.items() may differ from previous releases for a
613 given dict. Nothing is defined about this order, so no program should
614 rely on it. Nevertheless, it's easy to write test cases that rely on the
615 order by accident, typically because of printing the str() or repr() of a
616 dict to an "expected results" file. See Lib/test/test_support.py's new
617 sortdict(dict) function for a simple way to display a dict in sorted
618 order.
619
Tim Peters7a3bfc32001-06-12 01:22:22 +0000620- Many other small changes to dicts were made, resulting in faster
621 operation along the most common code paths.
622
Guido van Rossum10315822001-05-01 20:54:30 +0000623- Dictionary objects now support the "in" operator: "x in dict" means
624 the same as dict.has_key(x).
625
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000626- The update() method of dictionaries now accepts generic mapping
627 objects. Specifically the argument object must support the .keys()
628 and __getitem__() methods. This allows you to say, for example,
629 {}.update(UserDict())
630
Guido van Rossum10315822001-05-01 20:54:30 +0000631- Iterators were added; this is a generalized way of providing values
632 to a for loop. See PEP 234. There's a new built-in function iter()
633 to return an iterator. There's a new protocol to get the next value
634 from an iterator using the next() method (in Python) or the
635 tp_iternext slot (in C). There's a new protocol to get iterators
636 using the __iter__() method (in Python) or the tp_iter slot (in C).
637 Iterating (i.e. a for loop) over a dictionary generates its keys.
638 Iterating over a file generates its lines.
639
Tim Petersf553f892001-05-01 20:45:31 +0000640- The following functions were generalized to work nicely with iterator
641 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000642 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000643 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
644 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000645 join() method of strings
646 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000647 'x in y' and 'x not in y' (PySequence_Contains() in C API)
648 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000649 right-hand side of assignment statements with multiple targets, such as
650 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000651
Tim Petersd85e1022001-05-11 21:51:48 +0000652- Accessing module attributes is significantly faster (for example,
653 random.random or os.path or yourPythonModule.yourAttribute).
654
Tim Peterse63415e2001-05-08 04:38:29 +0000655- Comparing dictionary objects via == and != is faster, and now works even
656 if the keys and values don't support comparisons other than ==.
657
Tim Peters95bf9392001-05-10 08:32:44 +0000658- Comparing dictionaries in ways other than == and != is slower: there were
659 insecurities in the dict comparison implementation that could cause Python
660 to crash if the element comparison routines for the dict keys and/or
661 values mutated the dicts. Making the code bulletproof slowed it down.
662
Tim Peterseb28ef22001-06-02 05:27:19 +0000663- Collisions in dicts are resolved via a new approach, which can help
664 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000665 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000666 faster now. Thanks to Christian Tismer for pointing out the cause and
667 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000668
Tim Peters52e155e2001-06-16 05:42:57 +0000669- repr() is much faster for large containers (dict, list, tuple).
670
671
Tim Petersa814db52001-05-14 07:05:58 +0000672Library
673
Fred Drake960fdf92001-07-20 18:38:26 +0000674- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
675 were added to the string module. These a locale-indenpendent
676 constants, unlike letters, lowercase, and uppercase. These are now
677 use in appropriate locations in the standard library.
678
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000679- The flags used in dlopen calls can now be configured using
680 sys.setdlopenflags and queried using sys.getdlopenflags.
681
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000682- Fredrik Lundh's xmlrpclib is now a standard library module. This
683 provides full client-side XML-RPC support. In addition,
684 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
685 one asyncore-based). Thanks to Eric Raymond for the documentation.
686
Guido van Rossum643d3912001-07-05 14:46:25 +0000687- The xrange() object is simplified: it no longer supports slicing,
688 repetition, comparisons, efficient 'in' checking, the tolist()
689 method, or the start, stop and step attributes. See PEP 260.
690
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000691- A new function fnmatch.filter to filter lists of file names was added.
692
Barry Warsawffd674d2001-05-22 16:00:10 +0000693- calendar.py uses month and day names based on the current locale.
694
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000695- strop is now *really* obsolete (this was announced before with 1.6),
696 and issues DeprecationWarning when used (except for the four items
697 that are still imported into string.py).
698
Tim Petersa814db52001-05-14 07:05:58 +0000699- Cookie.py now sorts key+value pairs by key in output strings.
700
701- pprint.isrecursive(object) didn't correctly identify recursive objects.
702 Now it does.
703
Tim Peters95b3f782001-05-14 18:39:41 +0000704- pprint functions now much faster for large containers (tuple, list, dict).
705
Tim Peters7b9542a2001-06-10 23:40:19 +0000706- New 'q' and 'Q' format codes in the struct module, corresponding to C
707 types "long long" and "unsigned long long" (on Windows, __int64). In
708 native mode, these can be used only when the platform C compiler supports
709 these types (when HAVE_LONG_LONG is #define'd by the Python config
710 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000711 In standard mode, 'q' and 'Q' are supported on all platforms, and are
712 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000713
Guido van Rossum83213cc2001-06-12 16:48:52 +0000714- The site module installs a new built-in function 'help' that invokes
715 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
716 it displays a message reminding the user to use 'help()' or
717 'help(object)'.
718
Tim Petersa814db52001-05-14 07:05:58 +0000719Tests
720
721- New test_mutants.py runs dict comparisons where the key and value
722 comparison operators mutute the dicts randomly during comparison. This
723 rapidly causes Python to crash under earlier releases (not for the faint
724 of heart: it can also cause Win9x to freeze or reboot!).
725
726- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000727 pprint.isreadable() return sensible results. Also verifies that simple
728 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000729
Tim Peters4324aa32001-05-28 22:30:08 +0000730C API
731
732- Removed the unused last_is_sticky argument from the internal
733 _PyTuple_Resize(). If this affects you, you were cheating.
734
735
Guido van Rossum55a78992001-07-17 17:22:32 +0000736======================================================================
737
738
Guido van Rossumffe13be2001-04-16 18:46:45 +0000739What's New in Python 2.1 (final)?
740=================================
741
742We only changed a few things since the last release candidate, all in
743Python library code:
744
745- A bug in the locale module was fixed that affected locales which
746 define no grouping for numeric formatting.
747
748- A few bugs in the weakref module's implementations of weak
749 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
750 and the test suite was updated to check for these bugs.
751
752- An old bug in the os.path.walk() function (introduced in Python
753 2.0!) was fixed: a non-existent file would cause an exception
754 instead of being ignored.
755
756- Fixed a few bugs in the new symtable module found by Neil Norwitz's
757 PyChecker.
758
759
Guido van Rossum5b08f132001-04-16 02:05:23 +0000760What's New in Python 2.1c2?
761===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000762
Guido van Rossum5b08f132001-04-16 02:05:23 +0000763A flurry of small changes, and one showstopper fixed in the nick of
764time made it necessary to release another release candidate. The list
765here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000766
Guido van Rossum5b08f132001-04-16 02:05:23 +0000767Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000768
Guido van Rossum5b08f132001-04-16 02:05:23 +0000769- Tim discovered a nasty bug in the dictionary code, caused by
770 PyDict_Next() calling dict_resize(), and the GC code's use of
771 PyDict_Next() violating an assumption in dict_items(). This was
772 fixed with considerable amounts of band-aid, but the net effect is a
773 saner and more robust implementation.
774
775- Made a bunch of symbols static that were accidentally global.
776
777Build and Ports
778
779- The setup.py script didn't check for a new enough version of zlib
780 (1.1.3 is needed). Now it does.
781
782- Changed "make clean" target to also remove shared libraries.
783
784- Added a more general warning about the SGI Irix optimizer to README.
785
786Library
787
788- Fix a bug in urllib.basejoin("http://host", "../file.html") which
789 omitted the slash between host and file.html.
790
791- The mailbox module's _Mailbox class contained a completely broken
792 and undocumented seek() method. Ripped it out.
793
794- Fixed a bunch of typos in various library modules (urllib2, smtpd,
795 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
796
797- Fixed a few last-minute bugs in unittest.
798
799Extensions
800
801- Reverted the patch to the OpenSSL code in socketmodule.c to support
802 RAND_status() and the EGD, and the subsequent patch that tried to
803 fix it for pre-0.9.5 versions; the problem with the patch is that on
804 some systems it issues a warning whenever socket is imported, and
805 that's unacceptable.
806
807Tests
808
809- Fixed the pickle tests to work with "import test.test_pickle".
810
811- Tweaked test_locale.py to actually run the test Windows.
812
813- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
814 not "wb" (which is not a valid mode at all).
815
816- Fix pstats browser crashes. Import readline if it exists to make
817 the user interface nicer.
818
819- Add "import thread" to the top of test modules that import the
820 threading module (test_asynchat and test_threadedtempfile). This
821 prevents test failures caused by a broken threading module resulting
822 from a previously caught failed import.
823
824- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
825 needed on some platforms (e.g. Solaris 8) when the tests are run
826 twice in succession.
827
828- Skip rather than fail test_sunaudiodev if no audio device is found.
829
830
831What's New in Python 2.1c1?
832===========================
833
834This list was significantly updated when 2.1c2 was released; the 2.1c1
835release didn't mention most changes that were actually part of 2.1c1:
836
837Legal
838
839- Copyright was assigned to the Python Software Foundation (PSF) and a
840 PSF license (very similar to the CNRI license) was added.
841
842- The CNRI copyright notice was updated to include 2001.
843
844Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000845
Guido van Rossumc9932722001-04-12 02:31:27 +0000846- After a public outcry, assignment to __debug__ is no longer illegal;
847 instead, a warning is issued. It will become illegal in 2.2.
848
Guido van Rossum5b08f132001-04-16 02:05:23 +0000849- Fixed a core dump with "%#x" % 0, and changed the semantics so that
850 "%#x" now always prepends "0x", even if the value is zero.
851
852- Fixed some nits in the bytecode compiler.
853
854- Fixed core dumps when calling certain kinds of non-functions.
855
856- Fixed various core dumps caused by reference count bugs.
857
858Build and Ports
859
860- Use INSTALL_SCRIPT to install script files.
861
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000862- New port: SCO Unixware 7, by Billy G. Allie.
863
Guido van Rossum5b08f132001-04-16 02:05:23 +0000864- Updated RISCOS port.
865
866- Updated BeOS port and notes.
867
868- Various other porting problems resolved.
869
870Library
871
872- The TERMIOS and SOCKET modules are now truly obsolete and
873 unnecessary. Their symbols are incorporated in the termios and
874 socket modules.
875
876- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
877 better tests for pickling.
878
879- threading: make Condition.wait() robust against KeyboardInterrupt.
880
881- zipfile: add support to zipfile to support opening an archive
882 represented by an open file rather than a file name. Fix bug where
883 the archive was not properly closed. Fixed a bug in this bugfix
884 where flush() was called for a read-only file.
885
886- imputil: added an uninstall() method to the ImportManager.
887
888- Canvas: fixed bugs in lower() and tkraise() methods.
889
890- SocketServer: API change (added overridable close_request() method)
891 so that the TCP server can explicitly close the request.
892
893- pstats: Eric Raymond added a simple interactive statistics browser,
894 invoked when the module is run as a script.
895
896- locale: fixed a problem in format().
897
898- webbrowser: made it work when the BROWSER environment variable has a
899 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
900 KDE 2. Fixed some other nits.
901
902- unittest: changes to allow using a different exception than
903 AssertionError, and added a few more function aliases. Some other
904 small changes.
905
906- urllib, urllib2: fixed redirect problems and a coupleof other nits.
907
908- asynchat: fixed a critical bug in asynchat that slipped through the
909 2.1b2 release. Fixed another rare bug.
910
911- Fix some unqualified except: clauses (always a bad code example).
912
913XML
914
915- pyexpat: new API get_version_string().
916
917- Fixed some minidom bugs.
918
919Extensions
920
921- Fixed a core dump in _weakref. Removed the weakref.mapping()
922 function (it adds nothing to the API).
923
924- Rationalized the use of header files in the readline module, to make
925 it compile (albeit with some warnings) with the very recent readline
926 4.2, without breaking for earlier versions.
927
928- Hopefully fixed a buffering problem in linuxaudiodev.
929
930- Attempted a fix to make the OpenSSL support in the socket module
931 work again with pre-0.9.5 versions of OpenSSL.
932
933Tests
934
935- Added a test case for asynchat and asyncore.
936
937- Removed coupling between tests where one test failing could break
938 another.
939
940Tools
941
942- Ping added an interactive help browser to pydoc, fixed some nits
943 in the rest of the pydoc code, and added some features to his
944 inspect module.
945
946- An updated python-mode.el version 4.1 which integrates Ken
947 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
948 much nicer in XEmacs and Emacs. When stepping through your program
949 with pdb, in either the shell window or the *Python* window, the
950 source file and line will be tracked by an arrow. Very cool!
951
952- IDLE: syntax warnings in interactive mode are changed into errors.
953
954- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +0000955 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +0000956
957- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000958
Barry Warsaw11e89c72001-04-11 20:37:57 +0000959
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000960What's New in Python 2.1 beta 2?
961================================
962
Guido van Rossum053ae352001-03-22 14:17:21 +0000963(Unlisted are many fixed bugs, more documentation, etc.)
964
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000965Core language, builtins, and interpreter
966
Guido van Rossum053ae352001-03-22 14:17:21 +0000967- The nested scopes work (enabled by "from __future__ import
968 nested_scopes") is completed; in particular, the future now extends
969 into code executed through exec, eval() and execfile(), and into the
970 interactive interpreter.
971
972- When calling a base class method (e.g. BaseClass.__init__(self)),
973 this is now allowed even if self is not strictly spoken a class
974 instance (e.g. when using metaclasses or the Don Beaudry hook).
975
976- Slice objects are now comparable but not hashable; this prevents
977 dict[:] from being accepted but meaningless.
978
979- Complex division is now calculated using less braindead algorithms.
980 This doesn't change semantics except it's more likely to give useful
981 results in extreme cases. Complex repr() now uses full precision
982 like float repr().
983
984- sgmllib.py now calls handle_decl() for simple <!...> declarations.
985
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000986- It is illegal to assign to the name __debug__, which is set when the
987 interpreter starts. It is effectively a compile-time constant.
988
989- A warning will be issued if a global statement for a variable
990 follows a use or assignment of that variable.
991
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000992Standard library
993
Guido van Rossum053ae352001-03-22 14:17:21 +0000994- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
995 inspired by JUnit), is now part of the standard library. You now
996 have a choice of two testing frameworks: unittest requires you to
997 write testcases as separate code, doctest gathers them from
998 docstrings. Both approaches have their advantages and
999 disadvantages.
1000
1001- A new module Tix was added, which wraps the Tix extension library
1002 for Tk. With that module, it is not necessary to statically link
1003 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1004 require" command. See Demo/tix/.
1005
1006- tzparse.py is now obsolete.
1007
1008- In gzip.py, the seek() and tell() methods are removed -- they were
1009 non-functional anyway, and it's better if callers can test for their
1010 existence with hasattr().
1011
1012Python/C API
1013
1014- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1015 that's already in the dictionary during a PyDict_Next() iteration.
1016 This used to fail occasionally when a dictionary resize operation
1017 could be triggered that would rehash all the keys. All other
1018 modifications to the dictionary are still off-limits during a
1019 PyDict_Next() iteration!
1020
1021- New extended APIs related to passing compiler variables around.
1022
1023- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1024 implement isinstance() and issubclass().
1025
1026- Py_BuildValue() now has a "D" conversion to create a Python complex
1027 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001028
Fred Drake4e262a92001-03-22 18:26:47 +00001029- Extensions types which support weak references must now set the
1030 field allocated for the weak reference machinery to NULL themselves;
1031 this is done to avoid the cost of checking each object for having a
1032 weakly referencable type in PyObject_INIT(), since most types are
1033 not weakly referencable.
1034
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001035- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1036 free variables and cell variables to and from the frame's f_locals.
1037
1038- Variants of several functions defined in pythonrun.h have been added
1039 to support the nested_scopes future statement. The variants all end
1040 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1041 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1042 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001043 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001044
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001045Distutils
1046
1047- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1048 into the release tree.
1049
Tim Peters0e57abf2001-05-02 07:39:38 +00001050- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001051 (an uninstaller, more customization of the installer's display)
1052
1053- from Jack Jansen: added Mac-specific code to generate a dialog for
1054 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001055 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001056 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001057
1058- added 'platforms' and 'keywords' to the set of metadata that can be
1059 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001060
1061- applied patches from Jason Tishler to make the compiler class work with
1062 Cygwin.
1063
1064
Tim Peters2fe289a2001-03-01 22:19:38 +00001065What's New in Python 2.1 beta 1?
1066================================
Tim Petersd66595f2001-02-04 03:09:53 +00001067
1068Core language, builtins, and interpreter
1069
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001070- Following an outcry from the community about the amount of code
1071 broken by the nested scopes feature introduced in 2.1a2, we decided
1072 to make this feature optional, and to wait until Python 2.2 (or at
1073 least 6 months) to make it standard. The option can be enabled on a
1074 per-module basis by adding "from __future__ import nested_scopes" at
1075 the beginning of a module (before any other statements, but after
1076 comments and an optional docstring). See PEP 236 (Back to the
1077 __future__) for a description of the __future__ statement. PEP 227
1078 (Statically Nested Scopes) has been updated to reflect this change,
1079 and to clarify the semantics in a number of endcases.
1080
1081- The nested scopes code, when enabled, has been hardened, and most
1082 bugs and memory leaks in it have been fixed.
1083
1084- Compile-time warnings are now generated for a number of conditions
1085 that will break or change in meaning when nested scopes are enabled:
1086
1087 - Using "from...import *" or "exec" without in-clause in a function
1088 scope that also defines a lambda or nested function with one or
1089 more free (non-local) variables. The presence of the import* or
1090 bare exec makes it impossible for the compiler to determine the
1091 exact set of local variables in the outer scope, which makes it
1092 impossible to determine the bindings for free variables in the
1093 inner scope. To avoid the warning about import *, change it into
1094 an import of explicitly name object, or move the import* statement
1095 to the global scope; to avoid the warning about bare exec, use
1096 exec...in... (a good idea anyway -- there's a possibility that
1097 bare exec will be deprecated in the future).
1098
1099 - Use of a global variable in a nested scope with the same name as a
1100 local variable in a surrounding scope. This will change in
1101 meaning with nested scopes: the name in the inner scope will
1102 reference the variable in the outer scope rather than the global
1103 of the same name. To avoid the warning, either rename the outer
1104 variable, or use a global statement in the inner function.
1105
Neil Schemenauera35c6882001-02-27 04:45:05 +00001106- An optional object allocator has been included. This allocator is
1107 optimized for Python objects and should be faster and use less memory
1108 than the standard system allocator. It is not enabled by default
1109 because of possible thread safety problems. The allocator is only
1110 protected by the Python interpreter lock and it is possible that some
1111 extension modules require a thread safe allocator. The object
1112 allocator can be enabled by providing the "--with-pymalloc" option to
1113 configure.
1114
Tim Petersd66595f2001-02-04 03:09:53 +00001115Standard library
1116
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001117- pyexpat now detects the expat version if expat.h defines it. A
1118 number of additional handlers are provided, which are only available
1119 since expat 1.95. In addition, the methods SetParamEntityParsing and
1120 GetInputContext of Parser objects are available with 1.95.x
1121 only. Parser objects now provide the ordered_attributes and
1122 specified_attributes attributes. A new module expat.model was added,
1123 which offers a number of additional constants if 1.95.x is used.
1124
1125- xml.dom offers the new functions registerDOMImplementation and
1126 getDOMImplementation.
1127
1128- xml.dom.minidom offers a toprettyxml method. A number of DOM
1129 conformance issues have been resolved. In particular, Element now
1130 has an hasAttributes method, and the handling of namespaces was
1131 improved.
1132
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001133- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1134 getting information about live Python code, and pydoc.py, a module
1135 for interactively converting docstrings to HTML or text.
1136 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001137 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001138 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1139 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001140
Tim Peters1eff7962001-03-01 02:31:33 +00001141- New library module difflib.py, primarily packaging the SequenceMatcher
1142 class at the heart of the popular ndiff.py file-comparison tool.
1143
1144- doctest.py (a framework for verifying Python code examples in docstrings)
1145 is now part of the std library.
1146
Tim Petersd66595f2001-02-04 03:09:53 +00001147Windows changes
1148
Guido van Rossume3955a82001-03-02 14:05:59 +00001149- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1150 small GUI that lets you browse the module docstrings using your
1151 default web browser.
1152
Tim Peters1eff7962001-03-01 02:31:33 +00001153- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1154 Platforms) is implemented. See
1155
1156 http://python.sourceforge.net/peps/pep-0235.html
1157
1158 for full details, especially the "Current Lower-Left Semantics" section.
1159 The new Windows import rules are simpler than before:
1160
1161 A. If the PYTHONCASEOK environment variable exists, same as
1162 before: silently accept the first case-insensitive match of any
1163 kind; raise ImportError if none found.
1164
1165 B. Else search sys.path for the first case-sensitive match; raise
1166 ImportError if none found.
1167
1168 The same rules have been implented on other platforms with case-
1169 insensitive but case-preserving filesystems too (including Cygwin, and
1170 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001171
Tim Peters25a9ce32001-02-19 07:06:36 +00001172- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1173 what it's supposed to do (and does do under NT and 2000) via direct
1174 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001175 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001176 all Win9x systems before.
1177
Tim Peters1eff7962001-03-01 02:31:33 +00001178- Build: Subproject _test (effectively) renamed to _testcapi.
1179
Tim Peters2fe289a2001-03-01 22:19:38 +00001180New platforms
1181
1182- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1183 Thanks to Steven Majewski!
1184
1185- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1186 Tishler!
1187
Guido van Rossum9089b272001-03-02 06:49:50 +00001188- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1189 Schwertberger! See RISCOS/README for more information -- it seems
1190 that because of the bizarre filename conventions on RISCOS, no port
1191 to that platform is easy. Note that the new variable os.endsep is
1192 silently supported in order to make life easier on this platform,
1193 but we don't advertise it because it's not worth for most folks to
1194 care about RISCOS portability.
1195
Tim Peters25a9ce32001-02-19 07:06:36 +00001196
Tim Petersd7b5e882001-01-25 03:36:26 +00001197What's New in Python 2.1 alpha 2?
1198=================================
Tim Peters40ead762001-01-27 05:35:26 +00001199
Tim Petersd7b5e882001-01-25 03:36:26 +00001200Core language, builtins, and interpreter
1201
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001202- Scopes nest. If a name is used in a function or class, but is not
1203 local, the definition in the nearest enclosing function scope will
1204 be used. One consequence of this change is that lambda statements
1205 could reference variables in the namespaces where the lambda is
1206 defined. In some unusual cases, this change will break code.
1207
1208 In all previous version of Python, names were resolved in exactly
1209 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001210 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001211 function A is defined within a function B, the names bound in B are
1212 not visible in A. The new rules make names bound in B visible in A,
1213 unless A contains a name binding that hides the binding in B.
1214
1215 Section 4.1 of the reference manual describes the new scoping rules
1216 in detail. The test script in Lib/test/test_scope.py demonstrates
1217 some of the effects of the change.
1218
1219 The new rules will cause existing code to break if it defines nested
1220 functions where an outer function has local variables with the same
1221 name as globals or builtins used by the inner function. Example:
1222
1223 def munge(str):
1224 def helper(x):
1225 return str(x)
1226 if type(str) != type(''):
1227 str = helper(str)
1228 return str.strip()
1229
1230 Under the old rules, the name str in helper() is bound to the
1231 builtin function str(). Under the new rules, it will be bound to
1232 the argument named str and an error will occur when helper() is
1233 called.
1234
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001235- The compiler will report a SyntaxError if "from ... import *" occurs
1236 in a function or class scope. The language reference has documented
1237 that this case is illegal, but the compiler never checked for it.
1238 The recent introduction of nested scope makes the meaning of this
1239 form of name binding ambiguous. In a future release, the compiler
1240 may allow this form when there is no possibility of ambiguity.
1241
Tim Peters40ead762001-01-27 05:35:26 +00001242- repr(string) is easier to read, now using hex escapes instead of octal,
1243 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1244
1245 >>> "\texample \r\n" + chr(0) + chr(255)
1246 '\texample \r\n\x00\xff' # in 2.1
1247 '\011example \015\012\000\377' # in 2.0
1248
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001249- Functions are now compared and hashed by identity, not by value, since
1250 the func_code attribute is writable.
1251
Fred Drakefb9d7122001-02-01 20:00:40 +00001252- Weak references (PEP 205) have been added. This involves a few
1253 changes in the core, an extension module (_weakref), and a Python
1254 module (weakref). The weakref module is the public interface. It
1255 includes support for "explicit" weak references, proxy objects, and
1256 mappings with weakly held values.
1257
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001258- A 'continue' statement can now appear in a try block within the body
1259 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001260 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001261
Tim Petersd7b5e882001-01-25 03:36:26 +00001262Standard library
1263
Barry Warsaw30dbd142001-01-31 22:14:01 +00001264- mailbox.py now has a new class, PortableUnixMailbox which is
1265 identical to UnixMailbox but uses a more portable scheme for
1266 determining From_ separators. Also, the constructors for all the
1267 classes in this module have a new optional `factory' argument, which
1268 is a callable used when new message classes must be instantiated by
1269 the next() method.
1270
Tim Petersd7b5e882001-01-25 03:36:26 +00001271- random.py is now self-contained, and offers all the functionality of
1272 the now-deprecated whrandom.py. See the docs for details. random.py
1273 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001274 and restoring the internal state of the generator; and jumpahead(n),
1275 for quickly forcing the internal state to be the same as if n calls to
1276 random() had been made. The latter is particularly useful for multi-
1277 threaded programs, creating one instance of the random.Random() class for
1278 each thread, then using .jumpahead() to force each instance to use a
1279 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001280
Tim Peters0de88fc2001-02-01 04:59:18 +00001281- random.py's seed() function is new. For bit-for-bit compatibility with
1282 prior releases, use the whseed function instead. The new seed function
1283 addresses two problems: (1) The old function couldn't produce more than
1284 about 2**24 distinct internal states; the new one about 2**45 (the best
1285 that can be done in the Wichmann-Hill generator). (2) The old function
1286 sometimes produced identical internal states when passed distinct
1287 integers, and there was no simple way to predict when that would happen;
1288 the new one guarantees to produce distinct internal states for all
1289 arguments in [0, 27814431486576L).
1290
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001291- The socket module now supports raw packets on Linux. The socket
1292 family is AF_PACKET.
1293
Tim Peters9ea17ac2001-02-02 05:57:15 +00001294- test_capi.py is a start at running tests of the Python C API. The tests
1295 are implemented by the new Modules/_testmodule.c.
1296
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001297- A new extension module, _symtable, provides provisional access to the
1298 internal symbol table used by the Python compiler. A higher-level
1299 interface will be added on top of _symtable in a future release.
1300
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001301- Removed the obsolete soundex module.
1302
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001303- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1304 the isSameNode method; NamedNodeMap the get method.
1305
1306- xml.sax.expatreader supports the lexical handler property; it
1307 generates comment, startCDATA, and endCDATA events.
1308
Tim Petersee826f82001-01-31 19:39:44 +00001309Windows changes
1310
1311- Build procedure: the zlib project is built in a different way that
1312 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001313 the zlib binary used. See PCbuild\readme.txt for details. Your old
1314 zlib-related directories can be deleted; you'll need to download fresh
1315 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001316
Tim Peters9ea17ac2001-02-02 05:57:15 +00001317- Build: New subproject _test for the benefit of test_capi.py (see above).
1318
Tim Petersb16c56f2001-02-02 21:24:51 +00001319- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1320 interface to some Python compiler internals).
1321
1322- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001323 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001324
Tim Petersa3a3a032000-11-30 05:22:44 +00001325What's New in Python 2.1 alpha 1?
1326=================================
1327
1328Core language, builtins, and interpreter
1329
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001330- There is a new Unicode companion to the PyObject_Str() API
1331 called PyObject_Unicode(). It behaves in the same way as the
1332 former, but assures that the returned value is an Unicode object
1333 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001334
Guido van Rossumf98eda02001-01-17 15:54:45 +00001335- The comparison operators support "rich comparison overloading" (PEP
1336 207). C extension types can provide a rich comparison function in
1337 the new tp_richcompare slot in the type object. The cmp() function
1338 and the C function PyObject_Compare() first try the new rich
1339 comparison operators before trying the old 3-way comparison. There
1340 is also a new C API PyObject_RichCompare() (which also falls back on
1341 the old 3-way comparison, but does not constrain the outcome of the
1342 rich comparison to a Boolean result).
1343
1344 The rich comparison function takes two objects (at least one of
1345 which is guaranteed to have the type that provided the function) and
1346 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1347 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1348 object, which may be NotImplemented (in which case the tp_compare
1349 slot function is used as a fallback, if defined).
1350
1351 Classes can overload individual comparison operators by defining one
1352 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001353 __ge__. There are no explicit "reflected argument" versions of
1354 these; instead, __lt__ and __gt__ are each other's reflection,
1355 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1356 reflection (similar at the C level). No other implications are
1357 made; in particular, Python does not assume that == is the Boolean
1358 inverse of !=, or that < is the Boolean inverse of >=. This makes
1359 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001360
1361 Classes or types that want to implement (in)equality tests but not
1362 the ordering operators (i.e. unordered types) should implement ==
1363 and !=, and raise an error for the ordering operators.
1364
Guido van Rossuma88479f2001-01-18 14:28:08 +00001365 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001366 Boolean; e.g. a matrix type might want to return a matrix of bits
1367 for A < B, giving elementwise comparisons. Such types should ensure
1368 that any interpretation of their value in a Boolean context raises
1369 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1370 at the C level) to always raise an exception.
1371
Guido van Rossuma88479f2001-01-18 14:28:08 +00001372- Complex numbers use rich comparisons to define == and != but raise
1373 an exception for <, <=, > and >=. Unfortunately, this also means
1374 that cmp() of two complex numbers raises an exception when the two
1375 numbers differ. Since it is not mathematically meaningful to compare
1376 complex numbers except for equality, I hope that this doesn't break
1377 too much code.
1378
Tim Peters3389f192001-02-18 08:48:49 +00001379- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001380 not defined by the language, other than that it's arbitrary but
1381 consistent (see the Reference Manual). An implementation detail changed
1382 in 2.1a1 such that None now compares less than any other object. Code
1383 relying on this new behavior (like code that relied on the previous
1384 behavior) does so at its own risk.
1385
Barry Warsaw573b5412001-01-15 20:43:18 +00001386- Functions and methods now support getting and setting arbitrarily
1387 named attributes (PEP 232). Functions have a new __dict__
1388 (a.k.a. func_dict) which hold the function attributes. Methods get
1389 and set attributes on their underlying im_func. It is a TypeError
1390 to set an attribute on a bound method.
1391
Guido van Rossum051e3352001-01-15 19:11:10 +00001392- The xrange() object implementation has been improved so that
1393 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1394 limitation that in this case len(xrange(sys.maxint)) can't be
1395 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1396 work fine as long as the index i doesn't actually reach 2**31.
1397 (Python uses regular ints for sequence and string indices; fixing
1398 that is much more work.)
1399
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001400- Two changes to from...import:
1401
Guido van Rossumba381232001-02-03 15:06:40 +00001402 1) "from M import X" now works even if (after loading module M)
1403 sys.modules['M'] is not a real module; it's basically a getattr()
1404 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001405
1406 2) "from M import *" now looks for M.__all__ to decide which names to
1407 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1408 filters out names starting with '_' as before. Whether or not
1409 __all__ exists, there's no restriction on the type of M.
1410
Guido van Rossumf61f1662001-01-10 20:13:55 +00001411- File objects have a new method, xreadlines(). This is the fastest
1412 way to iterate over all lines in a file:
1413
1414 for line in file.xreadlines():
1415 ...do something to line...
1416
1417 See the xreadlines module (mentioned below) for how to do this for
1418 other file-like objects.
1419
1420- Even if you don't use file.xreadlines(), you may expect a speedup on
1421 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001422 quite a bit in platform-specific ways: on systems (like Linux) that
1423 support flockfile(), getc_unlocked(), and funlockfile(), those are
1424 used by default. On systems (like Windows) without getc_unlocked(),
1425 a complicated (but still thread-safe) method using fgets() is used by
1426 default.
1427
Tim Petersd52269b2001-01-25 06:23:18 +00001428 You can force use of the fgets() method by #define'ing
1429 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001430 getc_unlocked()).
1431
Tim Petersd52269b2001-01-25 06:23:18 +00001432 You can force fgets() not to be used by #define'ing
1433 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001434 test_bufio.py fails -- and let us know if it does!).
1435
1436- In addition, the fileinput module, while still slower than the other
1437 methods on most platforms, has been sped up too, by using
1438 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001439
1440- Support for run-time warnings has been added, including a new
1441 command line option (-W) to specify the disposition of warnings.
1442 See the description of the warnings module below.
1443
1444- Extensive changes have been made to the coercion code. This mostly
1445 affects extension modules (which can now implement mixed-type
1446 numerical operators without having to use coercion), but
1447 occasionally, in boundary cases the coercion semantics have changed
1448 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001449 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001450 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001451 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001452
Guido van Rossumf98eda02001-01-17 15:54:45 +00001453- In connection with the coercion changes, a new built-in singleton
1454 object, NotImplemented is defined. This can be returned for
1455 operations that wish to indicate they are not implemented for a
1456 particular combination of arguments. From C, this is
1457 Py_NotImplemented.
1458
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001459- The interpreter accepts now bytecode files on the command line even
1460 if they do not have a .pyc or .pyo extension. On Linux, after executing
1461
Martin v. Löwise214baa2001-02-04 22:37:56 +00001462import imp,sys,string
1463magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1464reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1465open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001466
1467 any byte code file can be used as an executable (i.e. as an argument
1468 to execve(2)).
1469
Tim Peters9940b802000-12-01 07:59:35 +00001470- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001471 character. In 1.6 and earlier, they never produced a sign,
1472 and raised an error if the value of the long was too large
1473 to fit in a Python int. In 2.0, they produced a sign if and
1474 only if too large to fit in an int. This was inconsistent
1475 across platforms (because the size of an int varies across
1476 platforms), and inconsistent with hex() and oct(). Example:
1477
1478 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001479 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001480 'ffffffbe' # in 2.0 and before, on 32-bit machines
1481 >>> hex(-0x42L)
1482 '-0x42L' # in all versions of Python
1483
Tim Peters9940b802000-12-01 07:59:35 +00001484 The behavior of %d formats for negative Python longs remains
1485 the same as in 2.0 (although in 1.6 and before, they raised
1486 an error if the long didn't fit in a Python int).
1487
1488 %u formats don't make sense for Python longs, but are allowed
1489 and treated the same as %d in 2.1. In 2.0, a negative long
1490 formatted via %u produced a sign if and only if too large to
1491 fit in an int. In 1.6 and earlier, a negative long formatted
1492 via %u raised an error if it was too big to fit in an int.
1493
Guido van Rossum3661d392000-12-12 22:10:31 +00001494- Dictionary objects have an odd new method, popitem(). This removes
1495 an arbitrary item from the dictionary and returns it (in the form of
1496 a (key, value) pair). This can be useful for algorithms that use a
1497 dictionary as a bag of "to do" items and repeatedly need to pick one
1498 item. Such algorithms normally end up running in quadratic time;
1499 using popitem() they can usually be made to run in linear time.
1500
Tim Peters36cdad12000-12-29 02:06:45 +00001501Standard library
1502
Thomas Woutersfe385252001-01-19 23:16:56 +00001503- In the time module, the time argument to the functions strftime,
1504 localtime, gmtime, asctime and ctime is now optional, defaulting to
1505 the current time (in the local timezone).
1506
Guido van Rossumda91f222001-01-15 16:36:08 +00001507- The ftplib module now defaults to passive mode, which is deemed a
1508 more useful default given that clients are often inside firewalls
1509 these days. Note that this could break if ftplib is used to connect
1510 to a *server* that is inside a firewall, from outside; this is
1511 expected to be a very rare situation. To fix that, you can call
1512 ftp.set_pasv(0).
1513
Martin v. Löwis10a27872001-01-13 09:54:41 +00001514- The module site now treats .pth files not only for path configuration,
1515 but also supports extensions to the initialization code: Lines starting
1516 with import are executed.
1517
Guido van Rossumf61f1662001-01-10 20:13:55 +00001518- There's a new module, warnings, which implements a mechanism for
1519 issuing and filtering warnings. There are some new built-in
1520 exceptions that serve as warning categories, and a new command line
1521 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1522 turns warnings into errors). warnings.warn(message[, category])
1523 issues a warning message; this can also be called from C as
1524 PyErr_Warn(category, message).
1525
1526- A new module xreadlines was added. This exports a single factory
1527 function, xreadlines(). The intention is that this code is the
1528 absolutely fastest way to iterate over all lines in an open
1529 file(-like) object:
1530
1531 import xreadlines
1532 for line in xreadlines.xreadlines(file):
1533 ...do something to line...
1534
1535 This is equivalent to the previous the speed record holder using
1536 file.readlines(sizehint). Note that if file is a real file object
1537 (as opposed to a file-like object), this is equivalent:
1538
1539 for line in file.xreadlines():
1540 ...do something to line...
1541
Tim Peters36cdad12000-12-29 02:06:45 +00001542- The bisect module has new functions bisect_left, insort_left,
1543 bisect_right and insort_right. The old names bisect and insort
1544 are now aliases for bisect_right and insort_right. XXX_right
1545 and XXX_left methods differ in what happens when the new element
1546 compares equal to one or more elements already in the list: the
1547 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001548 right. Code that doesn't care where equal elements end up should
1549 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001550
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001551- The new curses.panel module wraps the panel library that forms part
1552 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1553
Guido van Rossumf61f1662001-01-10 20:13:55 +00001554- The SocketServer module now sets the allow_reuse_address flag by
1555 default in the TCPServer class.
1556
1557- A new function, sys._getframe(), returns the stack frame pointer of
1558 the caller. This is intended only as a building block for
1559 higher-level mechanisms such as string interpolation.
1560
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001561- The pyexpat module supports a number of new handlers, which are
1562 available only in expat 1.2. If invocation of a callback fails, it
1563 will report an additional frame in the traceback. Parser objects
1564 participate now in garbage collection. If expat reports an unknown
1565 encoding, pyexpat will try to use a Python codec; that works only
1566 for single-byte charsets. The parser type objects is exposed as
1567 XMLParserObject.
1568
1569- xml.dom now offers standard definitions for symbolic node type and
1570 exception code constants, and a hierarchy of DOM exceptions. minidom
1571 was adjusted to use them.
1572
1573- The conformance of xml.dom.minidom to the DOM specification was
1574 improved. It detects a number of additional error cases; the
1575 previous/next relationship works even when the tree is modified;
1576 Node supports the normalize() method; NamedNodeMap, DocumentType and
1577 DOMImplementation classes were added; Element supports the
1578 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1579 method.
1580
Guido van Rossumf61f1662001-01-10 20:13:55 +00001581Build issues
1582
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001583- For Unix (and Unix-compatible) builds, configuration and building of
1584 extension modules is now greatly automated. Rather than having to
1585 edit the Modules/Setup file to indicate which modules should be
1586 built and where their include files and libraries are, a
1587 distutils-based setup.py script now takes care of building most
1588 extension modules. All extension modules built this way are built
1589 as shared libraries. Only a few modules that must be linked
1590 statically are still listed in the Setup file; you won't need to
1591 edit their configuration.
1592
1593- Python should now build out of the box on Cygwin. If it doesn't,
1594 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001595
1596- Python now always uses its own (renamed) implementation of getopt()
1597 -- there's too much variation among C library getopt()
1598 implementations.
1599
1600- C++ compilers are better supported; the CXX macro is always set to a
1601 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001602
Tim Petersd92dfe02000-12-12 01:18:41 +00001603Windows changes
1604
1605- select module: By default under Windows, a select() call
1606 can specify no more than 64 sockets. Python now boosts
1607 this Microsoft default to 512. If you need even more than
1608 that, see the MS docs (you'll need to #define FD_SETSIZE
1609 and recompile Python from source).
1610
Guido van Rossumf61f1662001-01-10 20:13:55 +00001611- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1612 subdirectory is no more!
1613
Tim Petersa3a3a032000-11-30 05:22:44 +00001614
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001615What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001616=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001617
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001618Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001619changes are in the file HISTORY. If you are making the jump directly
1620from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1621HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001622
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001623Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1624the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1625http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001626
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001627--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001628
1629======================================================================
1630
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001631What's new in 2.0 (since release candidate 1)?
1632==============================================
1633
1634Standard library
1635
1636- The copy_reg module was modified to clarify its intended use: to
1637 register pickle support for extension types, not for classes.
1638 pickle() will raise a TypeError if it is passed a class.
1639
1640- Fixed a bug in gettext's "normalize and expand" code that prevented
1641 it from finding an existing .mo file.
1642
1643- Restored support for HTTP/0.9 servers in httplib.
1644
Tim Peters989b7b92000-10-16 20:24:53 +00001645- The math module was changed to stop raising OverflowError in case of
1646 underflow, and return 0 instead in underflow cases. Whether Python
1647 used to raise OverflowError in case of underflow was platform-
1648 dependent (it did when the platform math library set errno to ERANGE
1649 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001650
1651- Fixed a bug in StringIO that occurred when the file position was not
1652 at the end of the file and write() was called with enough data to
1653 extend past the end of the file.
1654
1655- Fixed a bug that caused Tkinter error messages to get lost on
1656 Windows. The bug was fixed by replacing direct use of
1657 interp->result with Tcl_GetStringResult(interp).
1658
1659- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1660 redirect response.
1661
1662- Several changes were made to distutils: Some debugging code was
1663 removed from util. Fixed the installer used when an external zip
1664 program (like WinZip) is not found; the source code for this
1665 installer is in Misc/distutils. check_lib() was modified to behave
1666 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1667 test for whether installed modules are on sys.path was changed to
1668 use both normcase() and normpath().
1669
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001670- Several minor bugs were fixed in the xml package (the minidom,
1671 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001672
1673- The regression test driver (regrtest.py) behavior when invoked with
1674 -l changed: It now reports a count of objects that are recognized as
1675 garbage but not freed by the garbage collector.
1676
Tim Peters989b7b92000-10-16 20:24:53 +00001677- The regression test for the math module was changed to test
1678 exceptional behavior when the test is run in verbose mode. Python
1679 cannot yet guarantee consistent exception behavior across platforms,
1680 so the exception part of test_math is run only in verbose mode, and
1681 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001682
1683Internals
1684
1685- PyOS_CheckStack() has been disabled on Win64, where it caused
1686 test_sre to fail.
1687
1688Build issues
1689
1690- Changed compiler flags, so that gcc is always invoked with -Wall and
1691 -Wstrict-prototypes. Users compiling Python with GCC should see
1692 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001693 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001694 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001695
Tim Petersa3a3a032000-11-30 05:22:44 +00001696- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001697
1698Tools and other miscellany
1699
1700- The compiler in Tools/compiler was updated to support the new
1701 language features introduced in 2.0: extended print statement, list
1702 comprehensions, and augmented assignments. The new compiler should
1703 also be backwards compatible with Python 1.5.2; the compiler will
1704 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001705 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001706
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001707What's new in 2.0 release candidate 1 (since beta 2)?
1708=====================================================
1709
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001710What is release candidate 1?
1711
1712We believe that release candidate 1 will fix all known bugs that we
1713intend to fix for the 2.0 final release. This release should be a bit
1714more stable than the previous betas. We would like to see even more
1715widespread testing before the final release, so we are producing this
1716release candidate. The final release will be exactly the same unless
1717any show-stopping (or brown bag) bugs are found by testers of the
1718release candidate.
1719
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001720All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001721to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001722
1723Core language, builtins, and interpreter
1724
1725- A bug that caused crashes when __coerce__ was used with augmented
1726 assignment, e.g. +=, was fixed.
1727
1728- Raise ZeroDivisionError when raising zero to a negative number,
1729 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1730 power operator and the result of math.pow(0.0, -2.0) will vary by
1731 platform. On Linux, it raises a ValueError.
1732
1733- A bug in Unicode string interpolation was fixed that occasionally
1734 caused errors with formats including "%%". For example, the
1735 following expression "%% %s" % u"abc" no longer raises a TypeError.
1736
1737- Compilation of deeply nested expressions raises MemoryError instead
1738 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1739
1740- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1741 rendering them useless. They are now written in binary mode again.
1742
1743Standard library
1744
1745- Keyword arguments are now accepted for most pattern and match object
1746 methods in SRE, the standard regular expression engine.
1747
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001748- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001749 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001750
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001751- Several bugs in the Unicode handling and error handling in _tkinter
1752 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001753
1754- Fix memory management errors in Merge() and Tkapp_Call() routines.
1755
1756- Several changes were made to cStringIO to make it compatible with
1757 the file-like object interface and with StringIO. If operations are
1758 performed on a closed object, an exception is raised. The truncate
1759 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001760 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001761
1762- There were many changes made to the linuxaudiodev module and its
1763 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001764 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001765
1766 Note that this module is named poorly, because it should work
1767 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001768 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001769
1770 The module now raises exceptions when errors occur instead of
1771 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1772 audio) and defines a getptr() method that calls the
1773 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1774
1775- The library_version attribute, introduced in an earlier beta, was
1776 removed because it can not be supported with early versions of the C
1777 readline library, which provides no way to determine the version at
1778 compile-time.
1779
1780- The binascii module is now enabled on Win64.
1781
Tim Peters46446d62000-10-09 21:19:31 +00001782- tokenize.py no longer suffers "recursion depth" errors when parsing
1783 programs with very long string literals.
1784
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001785Internals
1786
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001787- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001788 which is called when the interpreter starts up to determine where
1789 the standard library is installed. These vulnerabilities affect all
1790 previous versions of Python and can be exploited by setting very
1791 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1792 setuid Python script, although use of the wrapper in
1793 Misc/setuid-prog.c will eliminate the vulnerability.
1794
1795- Fixed garbage collection bugs in instance creation that were
1796 triggered when errors occurred during initialization. The solution,
1797 applied in cPickle and in PyInstance_New(), is to call
1798 PyObject_GC_Init() after the initialization of the object's
1799 container attributes is complete.
1800
1801- pyexpat adds definitions of PyModule_AddStringConstant and
1802 PyModule_AddObject if the Python version is less than 2.0, which
1803 provides compatibility with PyXML on Python 1.5.2.
1804
1805- If the platform has a bogus definition for LONG_BIT (the number of
1806 bits in a long), an error will be reported at compile time.
1807
1808- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1809 collection crashes and possibly other, unreported crashes.
1810
1811- Fixed a memory leak in _PyUnicode_Fini().
1812
1813Build issues
1814
1815- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001816 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001817 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001818
1819- The mmap.PAGESIZE constant is now initialized using sysconf when
1820 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1821
1822- The md5 file should now compile on all platforms.
1823
1824- The select module now compiles on platforms that do not define
1825 POLLRDNORM and related constants.
1826
1827- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001828 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001829
Jeremy Hylton10921202000-10-09 18:34:12 +00001830- BeOS: A number of changes were made to the build and installation
1831 process. ar-fake now operates on a directory of object files.
1832 dl_export.h is gone, and its macros now appear on the mwcc command
1833 line during build on PPC BeOS.
1834
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001835- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001836 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001837
1838- Cygwin: Support for shared libraries, Tkinter, and sockets.
1839
1840- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1841
1842Tools and other miscellany
1843
1844- Removed debugging prints from main used with freeze.
1845
Tim Peters46446d62000-10-09 21:19:31 +00001846- IDLE auto-indent no longer crashes when it encounters Unicode
1847 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001848
1849What's new in 2.0 beta 2 (since beta 1)?
1850========================================
1851
1852Core language, builtins, and interpreter
1853
Tim Peters482c0212000-09-26 06:33:09 +00001854- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001855 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001856
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001857- Add -h and -V command line options to print the usage message and
1858 Python version number and exit immediately.
1859
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001860- eval() and exec accept Unicode objects as code parameters.
1861
1862- getattr() and setattr() now also accept Unicode objects for the
1863 attribute name, which are converted to strings using the default
1864 encoding before lookup.
1865
1866- Multiplication on string and Unicode now does proper bounds
1867 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1868 string is too long."
1869
1870- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001871 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001872
Jeremy Hylton1b618592000-09-26 05:32:36 +00001873
1874Standard library and extensions
1875
Guido van Rossum5b08f132001-04-16 02:05:23 +00001876- socket module: the OpenSSL code now adds support for RAND_status()
1877 and EGD (Entropy Gathering Device).
1878
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001879- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001880 argument checking; it still takes no arguments.
1881
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001882- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001883
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001884- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001885
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001886- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001887
1888- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001889 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001890
1891- copy: Copy Unicode objects atomically.
1892
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001893- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001894
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001895- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001896
Fred Drake67233bc2000-09-26 16:40:27 +00001897- dbm: Add get() and setdefault() methods to dbm object. Add constant
1898 `library' to module that names the library used. Added doc strings
1899 and method names to error messages. Uses configure to determine
1900 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
1901 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001902
1903- distutils: Update to version 0.9.3.
1904
1905- dl: Add several dl.RTLD_ constants.
1906
1907- fpectl: Now supported on FreeBSD.
1908
1909- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
1910 found by the collector will be saved in gc.garbage. This is useful
1911 for debugging a program that creates reference cycles.
1912
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001913- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00001914 of HTTP class. Do not close socket on zero-length response. Do not
1915 crash when server sends invalid content-length header.
1916
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001917- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001918
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001919- marshal: When reading a short, sign-extend on platforms where shorts
1920 are bigger than 16 bits. When reading a long, repair the unportable
1921 sign extension that was being done for 64-bit machines. (It assumed
1922 that signed right shift sign-extends.)
1923
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001924- operator: Add contains(), invert(), __invert__() as aliases for
1925 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001926
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001927- os: Add support for popen2() and popen3() on all platforms where
1928 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001929
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001930- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00001931 clicking on a file in Explorer (or passing the file name to the
1932 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001933
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001934- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00001935 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001936
1937- pickle: Now raises ValueError when an invalid pickle that contains
1938 a non-string repr where a string repr was expected. This behavior
1939 matches cPickle.
1940
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001941- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001942
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001943- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001944
1945- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001946 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001947 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001948
1949- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001950 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001951
1952- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00001953 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00001954 few cycles during startup since the first call to
1955 setdefaultencoding() will initialize the codec registry and the
1956 encodings package.
1957
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001958- socket: Support for size hint in readlines() method of object returned
1959 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001960
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001961- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001962 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001963 is followed by whitespace.
1964
Tim Petersa3a3a032000-11-30 05:22:44 +00001965- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001966
1967- struct: Check ranges for bytes and shorts.
1968
1969- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001970 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001971
1972- Tkinter: Image objects are now guaranteed to have unique ids. Set
1973 event.delta to zero if Tk version doesn't support mousewheel.
1974 Removed some debugging prints.
1975
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001976- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001977
Fred Drake67233bc2000-09-26 16:40:27 +00001978- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001979 which works around a bug in Norton AntiVirus 2000 that leads directly
1980 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001981
1982- xml: New version detection code allows PyXML to override standard
1983 XML package if PyXML version is greater than 0.6.1.
1984
Fred Drake64bb3802000-09-26 16:21:35 +00001985- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
1986 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
1987 tree only for nodes which are sufficiently interesting to a specific
1988 application. Does not provide the HTML-specific extensions. Still
1989 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001990
Fred Drake64bb3802000-09-26 16:21:35 +00001991- xml.sax: SAX 2 support for Python, including all the handler
1992 interfaces needed to process XML 1.0 compliant XML. Some
1993 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001994
Fred Drake64bb3802000-09-26 16:21:35 +00001995- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
1996 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001997
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001998
Jeremy Hylton1b618592000-09-26 05:32:36 +00001999C API
2000
2001- Add three new convenience functions for module initialization --
2002 PyModule_AddObject(), PyModule_AddIntConstant(), and
2003 PyModule_AddStringConstant().
2004
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002005- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002006 removed and add #error to Python.h if NULL isn't defined after
2007 #include of stdio.h.
2008
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002009- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002010 backwards compatibility (at the source level) with old extensions.
2011
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002012- A wrapper API was added for signal() and sigaction(). Instead of
2013 either function, always use PyOS_getsig() to get a signal handler
2014 and PyOS_setsig() to set one. A new convenience typedef
2015 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002016
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002017- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002018 internal data buffer and size of a string object -- or the default
2019 encoded version of a Unicode object.
2020
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002021- PyString_Size() and PyString_AsString() accept Unicode objects.
2022
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002023- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002024 exists). INT_MAX and LONG_MAX will always be defined, even if
2025 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002026
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002027- PyFloat_FromString takes a second argument, pend, that was
2028 effectively useless. It is now officially useless but preserved for
2029 backwards compatibility. If the pend argument is not NULL, *pend is
2030 set to NULL.
2031
2032- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2033 for the attribute name. See note on getattr() above.
2034
2035- A few bug fixes to argument processing for Unicode.
2036 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2037 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2038 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002039 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002040
2041- Py_BuildValue accepts B format (for bgen-generated code).
2042
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002043
Jeremy Hylton1b618592000-09-26 05:32:36 +00002044Internals
2045
2046- On Unix, fix code for finding Python installation directory so that
2047 it works when argv[0] is a relative path.
2048
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002049- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002050 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002051 rather than by generating a copy of the object.
2052
Tim Peters482c0212000-09-26 06:33:09 +00002053- Several of the internal Unicode tables are much smaller now, and
2054 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002055
Jeremy Hylton97693b02000-09-26 17:42:51 +00002056- In the garbage collector: Fixed bug in collection of tuples. Fixed
2057 bug that caused some instances to be removed from the container set
2058 while they were still live. Fixed parsing in gc.set_debug() for
2059 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002060
2061- Fixed refcount problem in instance deallocation that only occurred
2062 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2063
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002064- On Windows, getpythonregpath is now protected against null data in
2065 registry key.
2066
2067- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002068 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002069
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002070
Jeremy Hylton1b618592000-09-26 05:32:36 +00002071Build and platform-specific issues
2072
2073- Better support of GNU Pth via --with-pth configure option.
2074
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002075- Python/C API now properly exposed to dynamically-loaded extension
2076 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002077
2078- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2079 Don't define MS_SYNC to be zero when it is undefined. Added missing
2080 prototypes in posixmodule.c.
2081
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002082- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002083 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002084
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002085- Fix largefile support on older NetBSD systems and OpenBSD by adding
2086 define for TELL64.
2087
2088
2089Tools and other miscellany
2090
2091- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2092
2093- freeze: The modulefinder now works with 2.0 opcodes.
2094
Tim Petersa3a3a032000-11-30 05:22:44 +00002095- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002096 Move hackery of sys.argv until after the Tk instance has been
2097 created, which allows the application-specific Tkinter
2098 initialization to be executed if present; also pass an explicit
2099 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002100
Jeremy Hylton1b618592000-09-26 05:32:36 +00002101
2102What's new in 2.0 beta 1?
2103=========================
2104
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002105Source Incompatibilities
2106------------------------
2107
2108None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2109such as single-argument append(), connect() and bind(), and changes to
2110str(long) and repr(float).
2111
2112
2113Binary Incompatibilities
2114------------------------
2115
2116- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2117with Python 2.0; these extensions will have to be rebuilt for Python
21182.0.
2119
2120- On Windows, attempting to import a third party extension built for
2121Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2122can do about this. Check your PYTHONPATH environment variable!
2123
2124- Python bytecode files (*.pyc and *.pyo) are not compatible between
2125releases.
2126
2127
2128Overview of Changes Since 1.6
2129-----------------------------
2130
2131There are many new modules (including brand new XML support through
2132the xml package, and i18n support through the gettext module); a list
2133of all new modules is included below. Lots of bugs have been fixed.
2134
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002135The process for making major new changes to the language has changed
2136since Python 1.6. Enhancements must now be documented by a Python
2137Enhancement Proposal (PEP) before they can be accepted.
2138
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002139There are several important syntax enhancements, described in more
2140detail below:
2141
2142 - Augmented assignment, e.g. x += 1
2143
2144 - List comprehensions, e.g. [x**2 for x in range(10)]
2145
2146 - Extended import statement, e.g. import Module as Name
2147
2148 - Extended print statement, e.g. print >> file, "Hello"
2149
2150Other important changes:
2151
2152 - Optional collection of cyclical garbage
2153
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002154Python Enhancement Proposal (PEP)
2155---------------------------------
2156
2157PEP stands for Python Enhancement Proposal. A PEP is a design
2158document providing information to the Python community, or describing
2159a new feature for Python. The PEP should provide a concise technical
2160specification of the feature and a rationale for the feature.
2161
2162We intend PEPs to be the primary mechanisms for proposing new
2163features, for collecting community input on an issue, and for
2164documenting the design decisions that have gone into Python. The PEP
2165author is responsible for building consensus within the community and
2166documenting dissenting opinions.
2167
2168The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002169
2170Augmented Assignment
2171--------------------
2172
2173This must have been the most-requested feature of the past years!
2174Eleven new assignment operators were added:
2175
Guido van Rossume905e952000-09-05 12:42:46 +00002176 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002177
2178For example,
2179
2180 A += B
2181
2182is similar to
2183
2184 A = A + B
2185
2186except that A is evaluated only once (relevant when A is something
2187like dict[index].attr).
2188
2189However, if A is a mutable object, A may be modified in place. Thus,
2190if A is a number or a string, A += B has the same effect as A = A+B
2191(except A is only evaluated once); but if a is a list, A += B has the
2192same effect as A.extend(B)!
2193
2194Classes and built-in object types can override the new operators in
2195order to implement the in-place behavior; the not-in-place behavior is
2196used automatically as a fallback when an object doesn't implement the
2197in-place behavior. For classes, the method name is derived from the
2198method name for the corresponding not-in-place operator by inserting
2199an 'i' in front of the name, e.g. __iadd__ implements in-place
2200__add__.
2201
2202Augmented assignment was implemented by Thomas Wouters.
2203
2204
2205List Comprehensions
2206-------------------
2207
2208This is a flexible new notation for lists whose elements are computed
2209from another list (or lists). The simplest form is:
2210
2211 [<expression> for <variable> in <sequence>]
2212
Guido van Rossum56db0952000-09-06 23:34:25 +00002213For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002214This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002215
2216You can also add a condition:
2217
2218 [<expression> for <variable> in <sequence> if <condition>]
2219
2220For example, [w for w in words if w == w.lower()] would yield the list
2221of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002222than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002223
2224You can also have nested for loops and more than one 'if' clause. For
2225example, here's a function that flattens a sequence of sequences::
2226
2227 def flatten(seq):
2228 return [x for subseq in seq for x in subseq]
2229
2230 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2231
2232This prints
2233
2234 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2235
2236List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002237Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002238
2239
2240Extended Import Statement
2241-------------------------
2242
2243Many people have asked for a way to import a module under a different
2244name. This can be accomplished like this:
2245
2246 import foo
2247 bar = foo
2248 del foo
2249
2250but this common idiom gets old quickly. A simple extension of the
2251import statement now allows this to be written as follows:
2252
2253 import foo as bar
2254
2255There's also a variant for 'from ... import':
2256
2257 from foo import bar as spam
2258
2259This also works with packages; e.g. you can write this:
2260
2261 import test.regrtest as regrtest
2262
2263Note that 'as' is not a new keyword -- it is recognized only in this
2264context (this is only possible because the syntax for the import
2265statement doesn't involve expressions).
2266
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002267Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002268
2269
2270Extended Print Statement
2271------------------------
2272
2273Easily the most controversial new feature, this extension to the print
2274statement adds an option to make the output go to a different file
2275than the default sys.stdout.
2276
2277For example, to write an error message to sys.stderr, you can now
2278write:
2279
2280 print >> sys.stderr, "Error: bad dog!"
2281
2282As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002283evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002284
2285 print >> None, "Hello world"
2286
2287is equivalent to
2288
2289 print "Hello world"
2290
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002291Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002292
2293
2294Optional Collection of Cyclical Garbage
2295---------------------------------------
2296
2297Python is now equipped with a garbage collector that can hunt down
2298cyclical references between Python objects. It's no replacement for
2299reference counting; in fact, it depends on the reference counts being
2300correct, and decides that a set of objects belong to a cycle if all
2301their reference counts can be accounted for from their references to
2302each other. This devious scheme was first proposed by Eric Tiedemann,
2303and brought to implementation by Neil Schemenauer.
2304
2305There's a module "gc" that lets you control some parameters of the
2306garbage collection. There's also an option to the configure script
2307that lets you enable or disable the garbage collection. In 2.0b1,
2308it's on by default, so that we (hopefully) can collect decent user
2309experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002310performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002311off by default in the final 2.0 release.
2312
2313
2314Smaller Changes
2315---------------
2316
2317A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2318map(None, seq1, seq2, ...) when the sequences have the same length;
2319i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2320the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002321zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002322
2323sys.version_info is a tuple (major, minor, micro, level, serial).
2324
2325Dictionaries have an odd new method, setdefault(key, default).
2326dict.setdefault(key, default) returns dict[key] if it exists; if not,
2327it sets dict[key] to default and returns that value. Thus:
2328
2329 dict.setdefault(key, []).append(item)
2330
2331does the same work as this common idiom:
2332
2333 if not dict.has_key(key):
2334 dict[key] = []
2335 dict[key].append(item)
2336
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002337There are two new variants of SyntaxError that are raised for
2338indentation-related errors: IndentationError and TabError.
2339
2340Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2341escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002342
2343The limits on the size of expressions and file in Python source code
2344have been raised from 2**16 to 2**32. Previous versions of Python
2345were limited because the maximum argument size the Python VM accepted
2346was 2**16. This limited the size of object constructor expressions,
2347e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2348limit was raised thanks to a patch by Charles Waldman that effectively
2349fixes the problem. It is now much more likely that you will be
2350limited by available memory than by an arbitrary limit in Python.
2351
2352The interpreter's maximum recursion depth can be modified by Python
2353programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2354limit is the maximum number of recursive calls that can be made by
2355Python code. The limit exists to prevent infinite recursion from
2356overflowing the C stack and causing a core dump. The default value is
23571000. The maximum safe value for a particular platform can be found
2358by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002359
2360New Modules and Packages
2361------------------------
2362
2363atexit - for registering functions to be called when Python exits.
2364
2365imputil - Greg Stein's alternative API for writing custom import
2366hooks.
2367
2368pyexpat - an interface to the Expat XML parser, contributed by Paul
2369Prescod.
2370
2371xml - a new package with XML support code organized (so far) in three
2372subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2373would fill a volume. There's a special feature whereby a
2374user-installed package named _xmlplus overrides the standard
2375xmlpackage; this is intended to give the XML SIG a hook to distribute
2376backwards-compatible updates to the standard xml package.
2377
2378webbrowser - a platform-independent API to launch a web browser.
2379
2380
Guido van Rossume905e952000-09-05 12:42:46 +00002381Changed Modules
2382---------------
2383
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002384array -- new methods for array objects: count, extend, index, pop, and
2385remove
2386
2387binascii -- new functions b2a_hex and a2b_hex that convert between
2388binary data and its hex representation
2389
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002390calendar -- Many new functions that support features including control
2391over which day of the week is the first day, returning strings instead
2392of printing them. Also new symbolic constants for days of week,
2393e.g. MONDAY, ..., SUNDAY.
2394
2395cgi -- FieldStorage objects have a getvalue method that works like a
2396dictionary's get method and returns the value attribute of the object.
2397
2398ConfigParser -- The parser object has new methods has_option,
2399remove_section, remove_option, set, and write. They allow the module
2400to be used for writing config files as well as reading them.
2401
2402ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002403optionally support the RFC 959 REST command.
2404
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002405gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002406
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002407httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2408the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002409
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002410locale -- implement getdefaultlocale for Win32 and Macintosh
2411
2412marshal -- no longer dumps core when marshaling deeply nested or
2413recursive data structures
2414
2415os -- new functions isatty, seteuid, setegid, setreuid, setregid
2416
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002417os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2418support under Unix.
2419
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002420os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002421
2422os.path -- fix semantics of os.path.commonprefix
2423
2424smtplib -- support for sending very long messages
2425
2426socket -- new function getfqdn()
2427
2428readline -- new functions to read, write and truncate history files.
2429The readline section of the library reference manual contains an
2430example.
2431
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002432select -- add interface to poll system call
2433
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002434shutil -- new copyfileobj function
2435
2436SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2437HTTP server.
2438
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002439Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002440
2441urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002442e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002443
2444whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002445
2446
2447Obsolete Modules
2448----------------
2449
2450None. However note that 1.6 made a whole slew of modules obsolete:
2451stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2452poly, zmod, strop, util, whatsound.
2453
2454
2455Changed, New, Obsolete Tools
2456----------------------------
2457
Tim Peters8b092332000-09-05 20:15:25 +00002458None.
Guido van Rossume905e952000-09-05 12:42:46 +00002459
2460
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002461C-level Changes
2462---------------
2463
2464Several cleanup jobs were carried out throughout the source code.
2465
2466All C code was converted to ANSI C; we got rid of all uses of the
2467Py_PROTO() macro, which makes the header files a lot more readable.
2468
2469Most of the portability hacks were moved to a new header file,
2470pyport.h; several other new header files were added and some old
2471header files were removed, in an attempt to create a more rational set
2472of header files. (Few of these ever need to be included explicitly;
2473they are all included by Python.h.)
2474
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002475Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002476and Win64, especially for the new Intel Itanium processor. Mick also
2477added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002478
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002479The C APIs to return an object's size have been update to consistently
2480use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2481previous versions, the abstract interfaces used PyXXX_Length and the
2482concrete interfaces used PyXXX_Size. The old names,
2483e.g. PyObject_Length, are still available for backwards compatibility
2484at the API level, but are deprecated.
2485
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002486The PyOS_CheckStack function has been implemented on Windows by
2487Fredrik Lundh. It prevents Python from failing with a stack overflow
2488on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002489
2490The GC changes resulted in creation of two new slots on object,
2491tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002492the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002493
2494The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002495C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002496
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002497PyErr_Format has been updated to automatically calculate the size of
2498the buffer needed to hold the formatted result string. This change
2499prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002500
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002501New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002502
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002503PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2504that are the same as their non-Ex counterparts except they take an
2505extra flag argument that tells them to close the file when done.
2506
2507XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002508
Tim Peters8b092332000-09-05 20:15:25 +00002509
2510Windows Changes
2511---------------
2512
2513New popen2/popen3/peopen4 in os module (see Changed Modules above).
2514
2515os.popen is much more usable on Windows 95 and 98. See Microsoft
2516Knowledge Base article Q150956. The Win9x workaround described there
2517is implemented by the new w9xpopen.exe helper in the root of your
2518Python installation. Note that Python uses this internally; it is not
2519a standalone program.
2520
2521Administrator privileges are no longer required to install Python
2522on Windows NT or Windows 2000. If you have administrator privileges,
2523Python's registry info will be written under HKEY_LOCAL_MACHINE.
2524Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002525under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002526uses of Python, but will prevent some advanced uses from working
2527(for example, running a Python script as an NT service, or possibly
2528from CGI).
2529
2530[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2531installer; instead, it installs the needed Tcl/Tk files directly in the
2532Python directory. If you already have a Tcl/Tk installation, this
2533wastes some disk space (about 4 Megs) but avoids problems with
2534conflicting Tcl/Tk installations, and makes it much easier for Python
2535to ensure that Tcl/Tk can find all its files.
2536
2537[This was new in 1.6] The Windows installer now installs by default in
2538\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2539
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002540
2541Updates to the changes between 1.5.2 and 1.6
2542--------------------------------------------
2543
2544The 1.6 NEWS file can't be changed after the release is done, so here
2545is some late-breaking news:
2546
2547New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2548and changes to getlocale() and setlocale().
2549
2550The new module is now enabled per default.
2551
2552It is not true that the encodings codecs cannot be used for normal
2553strings: the string.encode() (which is also present on 8-bit strings
2554!) allows using them for 8-bit strings too, e.g. to convert files from
2555cp1252 (Windows) to latin-1 or vice-versa.
2556
2557Japanese codecs are available from Tamito KAJIYAMA:
2558http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2559
2560
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002561======================================================================