blob: 30e225f7976058842316fd9644e2b912771d3a81 [file] [log] [blame]
Tim Petersb07352e2001-09-08 01:25:47 +00001What's New in Python 2.2a4?
2===========================
3
Guido van Rossum808eea72001-09-25 04:15:41 +00004Type/class unification and new-style classes
5
6- pydoc and inspect are now aware of new-style classes;
7 e.g. help(list) at the interactive prompt now shows proper
8 documentation for all operations on list objects.
9
10- Applications using Jim Fulton's ExtensionClass module can now safely
11 be used with Python 2.2. In particular, Zope 2.4.1 now works with
12 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
13 examples also work again. It is hoped that Gtk and Boost also work
14 with 2.2a4 and beyond. (If you can confirm this, please write
15 webmaster@python.org; if there are still problems, please open a bug
16 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +000017
Tim Peters66c1a522001-09-24 21:17:50 +000018- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
19 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
20 in the constructed property object. fget, fset and fdel weren't
21 discoverable from Python in 2.2a3. __doc__ is new, and allows to
22 associate a docstring with a property.
23
Guido van Rossum808eea72001-09-25 04:15:41 +000024- Comparison overloading is now more completely implemented. For
25 example, a str subclass instance can properly be compared to a str
26 instance, and it can properly overload comparison. Ditto for most
27 other built-in object types.
28
29- The repr() of new-style classes has changed; instead of <type
30 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
31 *except* for built-in types, which are still rendered as <type
32 'Foo'> (to avoid upsetting existing code that might parse or
33 otherwise rely on repr() of certain type objects).
34
35- The repr() of new-style objects is now always <Foo object at XXX>;
36 previously, it was sometimes <Foo instance at XXX>.
37
38- For new-style classes, what was previously called __getattr__ is now
39 called __getattribute__. This method, if defined, is called for
40 *every* attribute access. A new __getattr__ hook mor similar to the
41 one in classic classes is defined which is called only if regular
42 attribute access raises AttributeError; to catch *all* attribute
43 access, you can use __getattribute__ (for new-style classes). If
44 both are defined, __getattribute__ is called first, and if it raises
45 AttributeError, __getattr__ is called.
46
47- The __class__ attribute of new-style objects can be assigned to.
48 The new class must have the same C-level object layout as the old
49 class.
50
51- The builtin file type can be subclassed now. In the usual pattern,
52 "file" is the name of the builtin type, and file() is a new builtin
53 constructor, with the same signature as the builtin open() function.
54 file() is now the preferred way to open a file.
55
56- Previously, __new__ would only see sequential arguments passed to
57 the type in a constructor call; __init__ would see both sequential
58 and keyword arguments. This made no sense whatsoever any more, so
59 now both __new__ and __init__ see all arguments.
60
61- Previously, hash() applied to an instance of a subclass of str or
62 unicode always returned 0. This has been repaired.
63
64- Previously, an operation on an instance of a subclass of an
65 immutable type (int, long, float, complex, tuple, str, unicode),
66 where the subtype didn't override the operation (and so the
67 operation was handled by the builtin type), could return that
68 instance instead a value of the base type. For example, if s was of
69 a str sublass type, s[:] returned s as-is. Now it returns a str
70 with the same value as s.
71
72Core
73
Tim Peters2c9aa5e2001-09-23 04:06:05 +000074- file.writelines() now accepts any iterable object producing strings.
75
Marc-André Lemburgaefd7662001-09-20 12:59:37 +000076- PyUnicode_FromEncodedObject() now works very much like
77 PyObject_Str(obj) in that it tries to use __str__/tp_str
78 on the object if the object is not a string or buffer. This
79 makes unicode() behave like str() when applied to non-string/buffer
80 objects.
81
Martin v. Löwis2777c022001-09-19 13:47:32 +000082- PyFile_WriteObject now passes Unicode object to the file's write
83 method. As a result, all file-like object which may be the target
84 of a print statement must support Unicode objects, i.e. they must
85 at least convert them into ASCII strings.
86
Guido van Rossum624c8af2001-09-18 15:21:04 +000087- Thread scheduling on Solaris should be improved; it is no longer
88 necessary to insert a small sleep at the start of a thread in order
89 to let other runnable threads be scheduled.
90
Tim Petersb07352e2001-09-08 01:25:47 +000091Library
92
Barry Warsaw2f600732001-09-24 04:28:10 +000093- The "email" package has been added. This is basically a port of the
94 mimelib package <http://sf.net/projects/mimelib> with API changes
95 and some implementations updated to use iterators and generators.
96
Tim Peters8a9c2842001-09-22 21:30:22 +000097- difflib.ndiff() and difflib.Differ.compare() are generators now. This
98 restores the ability of Tools/scripts/ndiff.py to start producing output
99 before the entire comparison is complete.
100
Barry Warsaw58b072d2001-09-22 04:44:21 +0000101- StringIO.StringIO instances and cStringIO.StringIO instances support
102 iteration just like file objects (i.e. their .readline() method is
103 called for each iteration until it returns an empty string).
104
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000105- The codecs module has grown four new helper APIs to access
106 builtin codecs: getencoder(), getdecoder(), getreader(),
107 getwriter().
108
Guido van Rossum624c8af2001-09-18 15:21:04 +0000109- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
110 simplifies writing XML RPC servers.
111
112- os.path.realpath(): a new function that returns the absoute pathname
113 after interpretation of symbolic links. On non-Unix systems, this
114 is an alias for os.path.abspath().
115
Tim Peters16a77ad2001-09-08 04:00:12 +0000116- operator.indexOf() (PySequence_Index() in the C API) now works with any
117 iterable object.
118
Guido van Rossum624c8af2001-09-18 15:21:04 +0000119- smtplib now supports various authentication and security features of
120 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000121
Guido van Rossum624c8af2001-09-18 15:21:04 +0000122- hmac: a new module implementing keyed hashing for message
123 authentication.
124
125- mimetypes now recognizes more extensions and file types. At the
126 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000127
Guido van Rossum624c8af2001-09-18 15:21:04 +0000128- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000129 Python 2.2 bytecode generation. It has also been promoted from a
130 Tool to a standard library package. (Tools/compiler still exists as
131 a sample driver.)
132
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000133Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000134
Tim Petersb07352e2001-09-08 01:25:47 +0000135Build
136
Guido van Rossum624c8af2001-09-18 15:21:04 +0000137- Large file support (LFS) is now automatic when the platform supports
138 it; no more manual configuration tweaks are needed. On Linux, at
139 least, it's possible to have a system whose C library supports large
140 files but whose kernel doesn't; in this case, large file support is
141 still enabled but doesn't do you any good unless you upgrade your
142 kernel or share your Python executable with another system whose
143 kernel has large file support.
144
145- The configure script now supplies plausible defaults in a
146 cross-compilation environment. This doesn't mean that the supplied
147 values are always correct, or that cross-compilation now works
148 flawlessly -- but it's a first step (and it shuts up most of
149 autoconf's warnings about AC_TRY_RUN).
150
151- The Unix build is now a bit less chatty, courtesy of the parser
152 generator. The build is completely silent (except for errors) when
153 using "make -s", thanks to a -q option to setup.py.
154
Tim Petersb07352e2001-09-08 01:25:47 +0000155C API
156
Guido van Rossum624c8af2001-09-18 15:21:04 +0000157- The "structmember" API now supports some new flag bits to deny read
158 and/or write access to attributes in restricted execution mode.
159
Tim Petersb07352e2001-09-08 01:25:47 +0000160New platforms
161
Guido van Rossum624c8af2001-09-18 15:21:04 +0000162- Compaq's iPAQ handheld, running the "familiar" Linux distribution
163 (http://familiar.handhelds.org).
164
Tim Petersb07352e2001-09-08 01:25:47 +0000165Tests
166
Tim Peters8a9c2842001-09-22 21:30:22 +0000167- The "classic" standard tests, which work by comparing stdout to
168 an expected-output file under Lib/test/output/, no longer stop at
169 the first mismatch. Instead the test is run to completion, and a
170 variant of ndiff-style comparison is used to report all differences.
171 This is much easier to understand than the previous style of reporting.
172
173- The unittest-based standard tests now use regrtest's test_main()
174 convention, instead of running as a side-effect of merely being
175 imported. This allows these tests to be run in more natural and
176 flexible ways as unittests, outside the regrtest framework.
177
178- regrtest.py is much better integrated with unittest and doctest now,
179 especially in regard to reporting errors.
180
Tim Petersb07352e2001-09-08 01:25:47 +0000181Windows
182
Guido van Rossum624c8af2001-09-18 15:21:04 +0000183- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000184 that support it (NTFS under Windows 2000). See "What's New in
185 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000186
Tim Petersb07352e2001-09-08 01:25:47 +0000187
Tim Petersedc99312001-08-22 21:36:50 +0000188What's New in Python 2.2a3?
189===========================
190
191Core
192
Tim Peters9fffa3e2001-09-04 05:14:19 +0000193- Conversion of long to float now raises OverflowError if the long is too
194 big to represent as a C double.
195
Tim Peters32f453e2001-09-03 08:35:41 +0000196- The 3-argument builtin pow() no longer allows a third non-None argument
197 if either of the first two arguments is a float, or if both are of
198 integer types and the second argument is negative (in which latter case
199 the arguments are converted to float, so this is really the same
200 restriction).
201
Tim Peters5d2b77c2001-09-03 05:47:38 +0000202- The builtin dir() now returns more information, and sometimes much
203 more, generally naming all attributes of an object, and all attributes
204 reachable from the object via its class, and from its class's base
205 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
206 an empty list. In 2.2a3,
207
208 >>> dir([])
209 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
210 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
211 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
212 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
213 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
214 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
215 'reverse', 'sort']
216
217 dir(module) continues to return only the module's attributes, though.
218
Tim Petersbdee63f2001-09-02 03:40:59 +0000219- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000220 than raising OverflowError. This is a partial implementation of PEP
221 237. You can use -Wdefault::OverflowWarning to enable a warning for
222 this situation, and -Werror::OverflowWarning to revert to the old
223 OverflowError exception.
224
Guido van Rossum61c345f2001-09-04 03:26:15 +0000225- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000226 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000227 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
228 -Qold, meaning the / operator has its classic meaning and no
229 warnings are issued. Using -Qwarn issues a run-time warning about
230 all uses of classic division for int and long arguments; -Qwarnall
231 also warns about classic division for float and complex arguments
232 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
233 new division by default, but only in the __main__ module. You can
234 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
235 __main__ module new division, and warns about classic division
236 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000237
Tim Petersbdee63f2001-09-02 03:40:59 +0000238- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000239 long, float, str, unicode, and tuple. (The types complex, list and
240 dictionary can also be subclassed; this was introduced earlier.)
241 Note that restrictions apply when subclassing immutable built-in
242 types: you can only affect the value of the instance by overloading
243 __new__. You can add mutable attributes, and the subclass instances
244 will have a __dict__ attribute, but you cannot change the "value"
245 (as implemented by the base class) of an immutable subclass instance
246 once it is created.
247
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000248- The dictionary constructor now takes an optional argument, a
249 mapping-like object, and initializes the dictionary from its
250 (key, value) pairs.
251
Tim Petersbdee63f2001-09-02 03:40:59 +0000252- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000253 "cooperative super calls" in a multiple inheritance setting. For an
254 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
255
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000256- A new built-in type, property, has been added. This enables the
257 creation of "properties". These are attributes implemented by
258 getter and setter functions (or only one of these for read-only or
259 write-only attributes), without the need to override __getattr__.
260 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000261
Tim Petersbdee63f2001-09-02 03:40:59 +0000262- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000263 liberalized, to allow leading zeroes. Examples of literals now
264 legal that were SyntaxErrors before:
265
266 00.0 0e3 0100j 07.5 00000000000000000008.
267
Tim Petersbdee63f2001-09-02 03:40:59 +0000268- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000269 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
270
Tim Petersedc99312001-08-22 21:36:50 +0000271Library
272
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000273- telnetlib includes symbolic names for the options, and support for
274 setting an option negotiation callback.
275
Tim Petersa40c7932001-09-05 22:36:56 +0000276- The new C standard no longer requires that math libraries set errno to
277 ERANGE on overflow. For platform libraries that exploit this new
278 freedom, Python's overflow-checking was wholly broken. A new overflow-
279 checking scheme attempts to repair that, but may not be reliable on all
280 platforms (C doesn't seem to provide anything both useful and portable
281 in this area anymore).
282
Martin v. Löwis44f86962001-09-05 13:44:54 +0000283- Asynchronous timeout actions are available through the new class
284 threading.Timer.
285
Tim Peters78526162001-09-05 00:53:45 +0000286- math.log and math.log10 now return sensible results for even huge
287 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
288
Tim Petersbdee63f2001-09-02 03:40:59 +0000289- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000290 currently held. See the docs for the imp module.
291
Tim Petersbdee63f2001-09-02 03:40:59 +0000292- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000293 dumps containing ints written on platforms where Python ints are 8 bytes.
294 When read on a box where Python ints are 4 bytes, such values are
295 converted to Python longs.
296
Tim Petersbdee63f2001-09-02 03:40:59 +0000297- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000298 code objects is no longer allowed. This plugs a security hole.
299
Steve Purcell6091cd62001-09-06 16:05:17 +0000300- unittest.TestResult instances no longer store references to tracebacks
301 generated by test failures. This prevents unexpected dangling references
302 to objects that should be garbage collected between tests.
303
Tim Petersedc99312001-08-22 21:36:50 +0000304Tools
305
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000306- Tools/scripts/fixdiv.py has been added which can be used to fix
307 division operators as per PEP 238.
308
Tim Petersedc99312001-08-22 21:36:50 +0000309Build
310
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000311- If you are an adventurous person using Mac OS X you may want to look at
312 Mac/OSX. There is a Makefile there that will build Python as a real Mac
313 application, which can be used for experimenting with Carbon or Cocoa.
314 Discussion of this on pythonmac-sig, please.
315
Tim Peters7eea37e2001-09-04 22:08:56 +0000316C API
317
318- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000319
Tim Peters9fffa3e2001-09-04 05:14:19 +0000320- Note that PyLong_AsDouble can fail! This has always been true, but no
321 callers checked for it. It's more likely to fail now, because overflow
322 errors are properly detected now. The proper way to check:
323
324 double x = PyLong_AsDouble(some_long_object);
325 if (x == -1.0 && PyErr_Occurred()) {
326 /* The conversion failed. */
327 }
328
Tim Petersbdee63f2001-09-02 03:40:59 +0000329- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000330 compile but will not participate in GC. To upgrade an extension
331 module:
332
333 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000334
Neil Schemenauer4042c692001-08-30 15:38:01 +0000335 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
336 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000337
Neil Schemenauer4042c692001-08-30 15:38:01 +0000338 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
339 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000340
Neil Schemenauer4042c692001-08-30 15:38:01 +0000341 - remove PyGC_HEAD_SIZE from object size calculations
342
343 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
344
Tim Petersbdee63f2001-09-02 03:40:59 +0000345- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000346 These can be used safely to construct string objects from a
347 sprintf-style format string (similar to the format string supported
348 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000349
Tim Petersedc99312001-08-22 21:36:50 +0000350New platforms
351
Tim Petersb7da0902001-09-02 23:01:43 +0000352- Stephen Hansen contributed patches sufficient to get a clean compile
353 under Borland C (Windows), but he reports problems running it and ran
354 out of time to complete the port. Volunteers? Expect a MemoryError
355 when importing the types module; this is probably shallow, and
356 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000357
Tim Petersedc99312001-08-22 21:36:50 +0000358Tests
359
360Windows
361
Tim Peters6e13a562001-09-06 00:32:15 +0000362- Large file support is now enabled on Win32 platforms as well as on
363 Win64. This means that, for example, you can use f.tell() and f.seek()
364 to manipulate files larger than 2 gigabytes (provided you have enough
365 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000366 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
367 filesize limit, and large file support makes no difference there.
368 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
369 NTFS has no practical limit on file size, and files of any size can be
370 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000371
Tim Petersbdee63f2001-09-02 03:40:59 +0000372- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000373 points to command.com (patch from Brian Quinlan).
374
Tim Petersedc99312001-08-22 21:36:50 +0000375
Tim Peters20f51a72001-07-21 02:31:40 +0000376What's New in Python 2.2a2?
377===========================
378
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000379Build
380
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000381- Tim Peters developed a brand new Windows installer using Wise 8.1,
382 generously donated to us by Wise Solutions.
383
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000384- configure supports a new option --enable-unicode, with the values
385 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
386 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000387
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000388- A new configure option --enable-framework builds a Mac OS X framework,
389 which "make frameworkinstall" will install. This provides a starting
390 point for more mac-like functionality, join pythonmac-sig@python.org
391 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000392
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000393- The NeXT platform is no longer supported.
394
395- The `new' module is now statically linked.
396
Tim Peters0afb6092001-08-15 06:06:44 +0000397Tools
398
399- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000400 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000401 the module docstring for details.
402
Tim Peters20f51a72001-07-21 02:31:40 +0000403Tests
404
Tim Peters5e824c32001-08-12 22:25:01 +0000405- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000406 platforms, allowing to give clearer test result output. regrtest
407 also has optional --use/-u switch to run normally disabled tests
408 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000409
Tim Peters20f51a72001-07-21 02:31:40 +0000410- Several new tests in the standard test suite, with special thanks to
411 Nick Mathewson.
412
413Core
414
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000415- The floor division operator // has been added as outlined in PEP
416 238. The / operator still provides classic division (and will until
417 Python 3.0) unless "from __future__ import division" is included, in
418 which case the / operator will provide true division. The operator
419 module provides truediv() and floordiv() functions. Augmented
420 assignment variants are included, as are the equivalent overloadable
421 methods and C API methods. See the PEP for a full discussion:
422 <http://python.sf.net/peps/pep-0238.html>
423
Tim Peters6cd6a822001-08-17 22:11:27 +0000424- Future statements are now effective in simulated interactive shells
425 (like IDLE). This should "just work" by magic, but read Michael
426 Hudson's "Future statements in simulated shells" PEP 264 for full
427 details: <http://python.sf.net/peps/pep-0264.html>.
428
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000429- The type/class unification (PEP 252-253) was integrated into the
430 trunk and is not so tentative any more (the exact specification of
431 some features is still tentative). A lot of work has done on fixing
432 bugs and adding robustness and features (performance still has to
433 come a long way).
434
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000435- Warnings about a mismatch in the Python API during extension import
436 now use the Python warning framework (which makes it possible to
437 write filters for these warnings).
438
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000439- A function's __dict__ (aka func_dict) will now always be a
440 dictionary. It used to be possible to delete it or set it to None,
441 but now both actions raise TypeErrors. It is still legal to set it
442 to a dictionary object. Getting func.__dict__ before any attributes
443 have been assigned now returns an empty dictionary instead of None.
444
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000445- A new command line option, -E, was added which disables the use of
446 all environment variables, or at least those that are specifically
447 significant to Python. Usually those have a name starting with
448 "PYTHON". This was used to fix a problem where the tests fail if
449 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
450 older distribution.
451
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000452Library
453
Tim Peters5e824c32001-08-12 22:25:01 +0000454- New class Differ and new functions ndiff() and restore() in difflib.py.
455 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000456 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000457
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000458- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
459 value using the minimal quoting required for the value; more
460 reliable than using xml.sax.saxutils.escape() for attribute values.
461
462- Readline completion support for cmd.Cmd was added.
463
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000464- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
465
466- Added function threading.BoundedSemaphore()
467
468- Added Ka-Ping Yee's cgitb.py module.
469
470- The `new' module now exposes the CO_xxx flags.
471
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000472New platforms
473
474C API
475
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000476- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
477 which provide a cross-platform implementations for the
478 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
479 the standard sprintf() and vsprintf() C lib APIs, these versions
480 apply bounds checking on the used buffer which enhances protection
481 against buffer overruns.
482
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000483- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000484 and extensions using different Unicode widths is rendered next to
485 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000486 will result in an ImportError. Unicode extensions writers must make
487 sure to check the Unicode width compatibility in their extensions by
488 using at least one of the mangled Unicode APIs in the extension.
489
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000490- Two new flags METH_NOARGS and METH_O are available in method definition
491 tables to simplify implementation of methods with no arguments and a
492 single untyped argument. Calling such methods is more efficient than
493 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
494 deprecated.
495
Tim Petersc1731372001-08-04 08:12:36 +0000496Windows
497
498- "import module" now compiles module.pyw if it exists and nothing else
499 relevant is found.
500
Tim Peters20f51a72001-07-21 02:31:40 +0000501
Guido van Rossum55a78992001-07-17 17:22:32 +0000502What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +0000503===========================
504
505Core
Tim Petersa814db52001-05-14 07:05:58 +0000506
Tim Peters6d6c1a32001-08-02 04:15:00 +0000507- TENTATIVELY, a large amount of code implementing much of what's
508 described in PEP 252 (Making Types Look More Like Classes) and PEP
509 253 (Subtyping Built-in Types) was added. This will be released
510 with Python 2.2a1. Documentation will be provided separately
511 through http://www.python.org/2.2/. The purpose of releasing this
512 with Python 2.2a1 is to test backwards compatibility. It is
513 possible, though not likely, that a decision is made not to release
514 this code as part of 2.2 final, if any serious backwards
515 incompapatibilities are found during alpha testing that cannot be
516 repaired.
517
Guido van Rossum55a78992001-07-17 17:22:32 +0000518- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000519 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000520 more 'yield' statements. See PEP 255. Since this adds a new
521 keyword to the language, this feature must be enabled by including a
522 future statement: "from __future__ import generators" (see PEP 236).
523 Generators will become a standard feature in a future release
524 (probably 2.3). Without this future statement, 'yield' remains an
525 ordinary identifier, but a warning is issued each time it is used.
526 (These warnings currently don't conform to the warnings framework of
527 PEP 230; we intend to fix this in 2.2a2.)
528
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000529- The UTF-16 codec was modified to be more RFC compliant. It will now
530 only remove BOM characters at the start of the string and then
531 only if running in native mode (UTF-16-LE and -BE won't remove a
532 leading BMO character).
533
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000534- Strings now have a new method .decode() to complement the already
535 existing .encode() method. These two methods provide direct access
536 to the corresponding decoders and encoders of the registered codecs.
537
538 To enhance the usability of the .encode() method, the special
539 casing of Unicode object return values was dropped (Unicode objects
540 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000541
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000542 Both methods will now return whatever the codec in charge of the
543 requested encoding returns as object, e.g. Unicode codecs will
544 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
545 will return u"äöü"). This enables codec writer to create codecs
546 for various simple to use conversions.
547
548 New codecs were added to demonstrate these new features (the .encode()
549 and .decode() columns indicate the type of the returned objects):
550
551 Name | .encode() | .decode() | Description
552 ----------------------------------------------------------------------
553 uu | string | string | UU codec (e.g. for email)
554 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000555 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000556 zlib | string | string | zlib compression
557 hex | string | string | 2-byte hex codec
558 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
559
Mark Hammond2a0af792001-05-14 03:09:36 +0000560- Some operating systems now support the concept of a default Unicode
561 encoding for file system operations. Notably, Windows supports 'mbcs'
562 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000563 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000564 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000565
566 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000567 functions that return filenames (such as os.listdir()) to return Python
568 string objects pre-encoded using the default file system encoding for
569 the platform. As this encoding is likely to be different from Python's
570 default encoding, converting this name to a Unicode object before passing
571 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000572 would attempt to use its default encoding (generally ASCII) rather than
573 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000574
Tim Petersa814db52001-05-14 07:05:58 +0000575 In general, this change simply removes surprises when working with
576 Unicode and the file system, making these operations work as you expect,
577 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000578 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000579
Tim Peters61dff2b2001-05-08 15:43:37 +0000580- Float (and complex) literals in source code were evaluated to full
581 precision only when running from a .py file; the same code loaded from a
582 .pyc (or .pyo) file could suffer numeric differences starting at about the
583 12th significant decimal digit. For example, on a machine with IEEE-754
584 floating arithmetic,
585
586 x = 9007199254740992.0
587 print long(x)
588
589 printed 9007199254740992 if run directly from .py, but 9007199254740000
590 if from a compiled (.pyc or .pyo) file. This was due to marshal using
591 str(float) instead of repr(float) when building code objects. marshal
592 now uses repr(float) instead, which should reproduce floats to full
593 machine precision (assuming the platform C float<->string I/O conversion
594 functions are of good quality).
595
596 This may cause floating-point results to change in some cases, and
597 usually for the better, but may also cause numerically unstable
598 algorithms to break.
599
Tim Peters2f228e72001-05-13 00:19:31 +0000600- The implementation of dicts suffers fewer collisions, which has speed
601 benefits. However, the order in which dict entries appear in dict.keys(),
602 dict.values() and dict.items() may differ from previous releases for a
603 given dict. Nothing is defined about this order, so no program should
604 rely on it. Nevertheless, it's easy to write test cases that rely on the
605 order by accident, typically because of printing the str() or repr() of a
606 dict to an "expected results" file. See Lib/test/test_support.py's new
607 sortdict(dict) function for a simple way to display a dict in sorted
608 order.
609
Tim Peters7a3bfc32001-06-12 01:22:22 +0000610- Many other small changes to dicts were made, resulting in faster
611 operation along the most common code paths.
612
Guido van Rossum10315822001-05-01 20:54:30 +0000613- Dictionary objects now support the "in" operator: "x in dict" means
614 the same as dict.has_key(x).
615
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000616- The update() method of dictionaries now accepts generic mapping
617 objects. Specifically the argument object must support the .keys()
618 and __getitem__() methods. This allows you to say, for example,
619 {}.update(UserDict())
620
Guido van Rossum10315822001-05-01 20:54:30 +0000621- Iterators were added; this is a generalized way of providing values
622 to a for loop. See PEP 234. There's a new built-in function iter()
623 to return an iterator. There's a new protocol to get the next value
624 from an iterator using the next() method (in Python) or the
625 tp_iternext slot (in C). There's a new protocol to get iterators
626 using the __iter__() method (in Python) or the tp_iter slot (in C).
627 Iterating (i.e. a for loop) over a dictionary generates its keys.
628 Iterating over a file generates its lines.
629
Tim Petersf553f892001-05-01 20:45:31 +0000630- The following functions were generalized to work nicely with iterator
631 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000632 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000633 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
634 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000635 join() method of strings
636 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000637 'x in y' and 'x not in y' (PySequence_Contains() in C API)
638 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000639 right-hand side of assignment statements with multiple targets, such as
640 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000641
Tim Petersd85e1022001-05-11 21:51:48 +0000642- Accessing module attributes is significantly faster (for example,
643 random.random or os.path or yourPythonModule.yourAttribute).
644
Tim Peterse63415e2001-05-08 04:38:29 +0000645- Comparing dictionary objects via == and != is faster, and now works even
646 if the keys and values don't support comparisons other than ==.
647
Tim Peters95bf9392001-05-10 08:32:44 +0000648- Comparing dictionaries in ways other than == and != is slower: there were
649 insecurities in the dict comparison implementation that could cause Python
650 to crash if the element comparison routines for the dict keys and/or
651 values mutated the dicts. Making the code bulletproof slowed it down.
652
Tim Peterseb28ef22001-06-02 05:27:19 +0000653- Collisions in dicts are resolved via a new approach, which can help
654 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000655 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000656 faster now. Thanks to Christian Tismer for pointing out the cause and
657 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000658
Tim Peters52e155e2001-06-16 05:42:57 +0000659- repr() is much faster for large containers (dict, list, tuple).
660
661
Tim Petersa814db52001-05-14 07:05:58 +0000662Library
663
Fred Drake960fdf92001-07-20 18:38:26 +0000664- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
665 were added to the string module. These a locale-indenpendent
666 constants, unlike letters, lowercase, and uppercase. These are now
667 use in appropriate locations in the standard library.
668
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000669- The flags used in dlopen calls can now be configured using
670 sys.setdlopenflags and queried using sys.getdlopenflags.
671
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000672- Fredrik Lundh's xmlrpclib is now a standard library module. This
673 provides full client-side XML-RPC support. In addition,
674 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
675 one asyncore-based). Thanks to Eric Raymond for the documentation.
676
Guido van Rossum643d3912001-07-05 14:46:25 +0000677- The xrange() object is simplified: it no longer supports slicing,
678 repetition, comparisons, efficient 'in' checking, the tolist()
679 method, or the start, stop and step attributes. See PEP 260.
680
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000681- A new function fnmatch.filter to filter lists of file names was added.
682
Barry Warsawffd674d2001-05-22 16:00:10 +0000683- calendar.py uses month and day names based on the current locale.
684
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000685- strop is now *really* obsolete (this was announced before with 1.6),
686 and issues DeprecationWarning when used (except for the four items
687 that are still imported into string.py).
688
Tim Petersa814db52001-05-14 07:05:58 +0000689- Cookie.py now sorts key+value pairs by key in output strings.
690
691- pprint.isrecursive(object) didn't correctly identify recursive objects.
692 Now it does.
693
Tim Peters95b3f782001-05-14 18:39:41 +0000694- pprint functions now much faster for large containers (tuple, list, dict).
695
Tim Peters7b9542a2001-06-10 23:40:19 +0000696- New 'q' and 'Q' format codes in the struct module, corresponding to C
697 types "long long" and "unsigned long long" (on Windows, __int64). In
698 native mode, these can be used only when the platform C compiler supports
699 these types (when HAVE_LONG_LONG is #define'd by the Python config
700 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000701 In standard mode, 'q' and 'Q' are supported on all platforms, and are
702 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000703
Guido van Rossum83213cc2001-06-12 16:48:52 +0000704- The site module installs a new built-in function 'help' that invokes
705 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
706 it displays a message reminding the user to use 'help()' or
707 'help(object)'.
708
Tim Petersa814db52001-05-14 07:05:58 +0000709Tests
710
711- New test_mutants.py runs dict comparisons where the key and value
712 comparison operators mutute the dicts randomly during comparison. This
713 rapidly causes Python to crash under earlier releases (not for the faint
714 of heart: it can also cause Win9x to freeze or reboot!).
715
716- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000717 pprint.isreadable() return sensible results. Also verifies that simple
718 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000719
Tim Peters4324aa32001-05-28 22:30:08 +0000720C API
721
722- Removed the unused last_is_sticky argument from the internal
723 _PyTuple_Resize(). If this affects you, you were cheating.
724
725
Guido van Rossum55a78992001-07-17 17:22:32 +0000726======================================================================
727
728
Guido van Rossumffe13be2001-04-16 18:46:45 +0000729What's New in Python 2.1 (final)?
730=================================
731
732We only changed a few things since the last release candidate, all in
733Python library code:
734
735- A bug in the locale module was fixed that affected locales which
736 define no grouping for numeric formatting.
737
738- A few bugs in the weakref module's implementations of weak
739 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
740 and the test suite was updated to check for these bugs.
741
742- An old bug in the os.path.walk() function (introduced in Python
743 2.0!) was fixed: a non-existent file would cause an exception
744 instead of being ignored.
745
746- Fixed a few bugs in the new symtable module found by Neil Norwitz's
747 PyChecker.
748
749
Guido van Rossum5b08f132001-04-16 02:05:23 +0000750What's New in Python 2.1c2?
751===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000752
Guido van Rossum5b08f132001-04-16 02:05:23 +0000753A flurry of small changes, and one showstopper fixed in the nick of
754time made it necessary to release another release candidate. The list
755here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000756
Guido van Rossum5b08f132001-04-16 02:05:23 +0000757Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000758
Guido van Rossum5b08f132001-04-16 02:05:23 +0000759- Tim discovered a nasty bug in the dictionary code, caused by
760 PyDict_Next() calling dict_resize(), and the GC code's use of
761 PyDict_Next() violating an assumption in dict_items(). This was
762 fixed with considerable amounts of band-aid, but the net effect is a
763 saner and more robust implementation.
764
765- Made a bunch of symbols static that were accidentally global.
766
767Build and Ports
768
769- The setup.py script didn't check for a new enough version of zlib
770 (1.1.3 is needed). Now it does.
771
772- Changed "make clean" target to also remove shared libraries.
773
774- Added a more general warning about the SGI Irix optimizer to README.
775
776Library
777
778- Fix a bug in urllib.basejoin("http://host", "../file.html") which
779 omitted the slash between host and file.html.
780
781- The mailbox module's _Mailbox class contained a completely broken
782 and undocumented seek() method. Ripped it out.
783
784- Fixed a bunch of typos in various library modules (urllib2, smtpd,
785 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
786
787- Fixed a few last-minute bugs in unittest.
788
789Extensions
790
791- Reverted the patch to the OpenSSL code in socketmodule.c to support
792 RAND_status() and the EGD, and the subsequent patch that tried to
793 fix it for pre-0.9.5 versions; the problem with the patch is that on
794 some systems it issues a warning whenever socket is imported, and
795 that's unacceptable.
796
797Tests
798
799- Fixed the pickle tests to work with "import test.test_pickle".
800
801- Tweaked test_locale.py to actually run the test Windows.
802
803- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
804 not "wb" (which is not a valid mode at all).
805
806- Fix pstats browser crashes. Import readline if it exists to make
807 the user interface nicer.
808
809- Add "import thread" to the top of test modules that import the
810 threading module (test_asynchat and test_threadedtempfile). This
811 prevents test failures caused by a broken threading module resulting
812 from a previously caught failed import.
813
814- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
815 needed on some platforms (e.g. Solaris 8) when the tests are run
816 twice in succession.
817
818- Skip rather than fail test_sunaudiodev if no audio device is found.
819
820
821What's New in Python 2.1c1?
822===========================
823
824This list was significantly updated when 2.1c2 was released; the 2.1c1
825release didn't mention most changes that were actually part of 2.1c1:
826
827Legal
828
829- Copyright was assigned to the Python Software Foundation (PSF) and a
830 PSF license (very similar to the CNRI license) was added.
831
832- The CNRI copyright notice was updated to include 2001.
833
834Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000835
Guido van Rossumc9932722001-04-12 02:31:27 +0000836- After a public outcry, assignment to __debug__ is no longer illegal;
837 instead, a warning is issued. It will become illegal in 2.2.
838
Guido van Rossum5b08f132001-04-16 02:05:23 +0000839- Fixed a core dump with "%#x" % 0, and changed the semantics so that
840 "%#x" now always prepends "0x", even if the value is zero.
841
842- Fixed some nits in the bytecode compiler.
843
844- Fixed core dumps when calling certain kinds of non-functions.
845
846- Fixed various core dumps caused by reference count bugs.
847
848Build and Ports
849
850- Use INSTALL_SCRIPT to install script files.
851
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000852- New port: SCO Unixware 7, by Billy G. Allie.
853
Guido van Rossum5b08f132001-04-16 02:05:23 +0000854- Updated RISCOS port.
855
856- Updated BeOS port and notes.
857
858- Various other porting problems resolved.
859
860Library
861
862- The TERMIOS and SOCKET modules are now truly obsolete and
863 unnecessary. Their symbols are incorporated in the termios and
864 socket modules.
865
866- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
867 better tests for pickling.
868
869- threading: make Condition.wait() robust against KeyboardInterrupt.
870
871- zipfile: add support to zipfile to support opening an archive
872 represented by an open file rather than a file name. Fix bug where
873 the archive was not properly closed. Fixed a bug in this bugfix
874 where flush() was called for a read-only file.
875
876- imputil: added an uninstall() method to the ImportManager.
877
878- Canvas: fixed bugs in lower() and tkraise() methods.
879
880- SocketServer: API change (added overridable close_request() method)
881 so that the TCP server can explicitly close the request.
882
883- pstats: Eric Raymond added a simple interactive statistics browser,
884 invoked when the module is run as a script.
885
886- locale: fixed a problem in format().
887
888- webbrowser: made it work when the BROWSER environment variable has a
889 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
890 KDE 2. Fixed some other nits.
891
892- unittest: changes to allow using a different exception than
893 AssertionError, and added a few more function aliases. Some other
894 small changes.
895
896- urllib, urllib2: fixed redirect problems and a coupleof other nits.
897
898- asynchat: fixed a critical bug in asynchat that slipped through the
899 2.1b2 release. Fixed another rare bug.
900
901- Fix some unqualified except: clauses (always a bad code example).
902
903XML
904
905- pyexpat: new API get_version_string().
906
907- Fixed some minidom bugs.
908
909Extensions
910
911- Fixed a core dump in _weakref. Removed the weakref.mapping()
912 function (it adds nothing to the API).
913
914- Rationalized the use of header files in the readline module, to make
915 it compile (albeit with some warnings) with the very recent readline
916 4.2, without breaking for earlier versions.
917
918- Hopefully fixed a buffering problem in linuxaudiodev.
919
920- Attempted a fix to make the OpenSSL support in the socket module
921 work again with pre-0.9.5 versions of OpenSSL.
922
923Tests
924
925- Added a test case for asynchat and asyncore.
926
927- Removed coupling between tests where one test failing could break
928 another.
929
930Tools
931
932- Ping added an interactive help browser to pydoc, fixed some nits
933 in the rest of the pydoc code, and added some features to his
934 inspect module.
935
936- An updated python-mode.el version 4.1 which integrates Ken
937 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
938 much nicer in XEmacs and Emacs. When stepping through your program
939 with pdb, in either the shell window or the *Python* window, the
940 source file and line will be tracked by an arrow. Very cool!
941
942- IDLE: syntax warnings in interactive mode are changed into errors.
943
944- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +0000945 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +0000946
947- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000948
Barry Warsaw11e89c72001-04-11 20:37:57 +0000949
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000950What's New in Python 2.1 beta 2?
951================================
952
Guido van Rossum053ae352001-03-22 14:17:21 +0000953(Unlisted are many fixed bugs, more documentation, etc.)
954
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000955Core language, builtins, and interpreter
956
Guido van Rossum053ae352001-03-22 14:17:21 +0000957- The nested scopes work (enabled by "from __future__ import
958 nested_scopes") is completed; in particular, the future now extends
959 into code executed through exec, eval() and execfile(), and into the
960 interactive interpreter.
961
962- When calling a base class method (e.g. BaseClass.__init__(self)),
963 this is now allowed even if self is not strictly spoken a class
964 instance (e.g. when using metaclasses or the Don Beaudry hook).
965
966- Slice objects are now comparable but not hashable; this prevents
967 dict[:] from being accepted but meaningless.
968
969- Complex division is now calculated using less braindead algorithms.
970 This doesn't change semantics except it's more likely to give useful
971 results in extreme cases. Complex repr() now uses full precision
972 like float repr().
973
974- sgmllib.py now calls handle_decl() for simple <!...> declarations.
975
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000976- It is illegal to assign to the name __debug__, which is set when the
977 interpreter starts. It is effectively a compile-time constant.
978
979- A warning will be issued if a global statement for a variable
980 follows a use or assignment of that variable.
981
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000982Standard library
983
Guido van Rossum053ae352001-03-22 14:17:21 +0000984- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
985 inspired by JUnit), is now part of the standard library. You now
986 have a choice of two testing frameworks: unittest requires you to
987 write testcases as separate code, doctest gathers them from
988 docstrings. Both approaches have their advantages and
989 disadvantages.
990
991- A new module Tix was added, which wraps the Tix extension library
992 for Tk. With that module, it is not necessary to statically link
993 Tix with _tkinter, since Tix will be loaded with Tcl's "package
994 require" command. See Demo/tix/.
995
996- tzparse.py is now obsolete.
997
998- In gzip.py, the seek() and tell() methods are removed -- they were
999 non-functional anyway, and it's better if callers can test for their
1000 existence with hasattr().
1001
1002Python/C API
1003
1004- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1005 that's already in the dictionary during a PyDict_Next() iteration.
1006 This used to fail occasionally when a dictionary resize operation
1007 could be triggered that would rehash all the keys. All other
1008 modifications to the dictionary are still off-limits during a
1009 PyDict_Next() iteration!
1010
1011- New extended APIs related to passing compiler variables around.
1012
1013- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1014 implement isinstance() and issubclass().
1015
1016- Py_BuildValue() now has a "D" conversion to create a Python complex
1017 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001018
Fred Drake4e262a92001-03-22 18:26:47 +00001019- Extensions types which support weak references must now set the
1020 field allocated for the weak reference machinery to NULL themselves;
1021 this is done to avoid the cost of checking each object for having a
1022 weakly referencable type in PyObject_INIT(), since most types are
1023 not weakly referencable.
1024
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001025- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1026 free variables and cell variables to and from the frame's f_locals.
1027
1028- Variants of several functions defined in pythonrun.h have been added
1029 to support the nested_scopes future statement. The variants all end
1030 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1031 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1032 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001033 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001034
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001035Distutils
1036
1037- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1038 into the release tree.
1039
Tim Peters0e57abf2001-05-02 07:39:38 +00001040- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001041 (an uninstaller, more customization of the installer's display)
1042
1043- from Jack Jansen: added Mac-specific code to generate a dialog for
1044 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001045 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001046 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001047
1048- added 'platforms' and 'keywords' to the set of metadata that can be
1049 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001050
1051- applied patches from Jason Tishler to make the compiler class work with
1052 Cygwin.
1053
1054
Tim Peters2fe289a2001-03-01 22:19:38 +00001055What's New in Python 2.1 beta 1?
1056================================
Tim Petersd66595f2001-02-04 03:09:53 +00001057
1058Core language, builtins, and interpreter
1059
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001060- Following an outcry from the community about the amount of code
1061 broken by the nested scopes feature introduced in 2.1a2, we decided
1062 to make this feature optional, and to wait until Python 2.2 (or at
1063 least 6 months) to make it standard. The option can be enabled on a
1064 per-module basis by adding "from __future__ import nested_scopes" at
1065 the beginning of a module (before any other statements, but after
1066 comments and an optional docstring). See PEP 236 (Back to the
1067 __future__) for a description of the __future__ statement. PEP 227
1068 (Statically Nested Scopes) has been updated to reflect this change,
1069 and to clarify the semantics in a number of endcases.
1070
1071- The nested scopes code, when enabled, has been hardened, and most
1072 bugs and memory leaks in it have been fixed.
1073
1074- Compile-time warnings are now generated for a number of conditions
1075 that will break or change in meaning when nested scopes are enabled:
1076
1077 - Using "from...import *" or "exec" without in-clause in a function
1078 scope that also defines a lambda or nested function with one or
1079 more free (non-local) variables. The presence of the import* or
1080 bare exec makes it impossible for the compiler to determine the
1081 exact set of local variables in the outer scope, which makes it
1082 impossible to determine the bindings for free variables in the
1083 inner scope. To avoid the warning about import *, change it into
1084 an import of explicitly name object, or move the import* statement
1085 to the global scope; to avoid the warning about bare exec, use
1086 exec...in... (a good idea anyway -- there's a possibility that
1087 bare exec will be deprecated in the future).
1088
1089 - Use of a global variable in a nested scope with the same name as a
1090 local variable in a surrounding scope. This will change in
1091 meaning with nested scopes: the name in the inner scope will
1092 reference the variable in the outer scope rather than the global
1093 of the same name. To avoid the warning, either rename the outer
1094 variable, or use a global statement in the inner function.
1095
Neil Schemenauera35c6882001-02-27 04:45:05 +00001096- An optional object allocator has been included. This allocator is
1097 optimized for Python objects and should be faster and use less memory
1098 than the standard system allocator. It is not enabled by default
1099 because of possible thread safety problems. The allocator is only
1100 protected by the Python interpreter lock and it is possible that some
1101 extension modules require a thread safe allocator. The object
1102 allocator can be enabled by providing the "--with-pymalloc" option to
1103 configure.
1104
Tim Petersd66595f2001-02-04 03:09:53 +00001105Standard library
1106
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001107- pyexpat now detects the expat version if expat.h defines it. A
1108 number of additional handlers are provided, which are only available
1109 since expat 1.95. In addition, the methods SetParamEntityParsing and
1110 GetInputContext of Parser objects are available with 1.95.x
1111 only. Parser objects now provide the ordered_attributes and
1112 specified_attributes attributes. A new module expat.model was added,
1113 which offers a number of additional constants if 1.95.x is used.
1114
1115- xml.dom offers the new functions registerDOMImplementation and
1116 getDOMImplementation.
1117
1118- xml.dom.minidom offers a toprettyxml method. A number of DOM
1119 conformance issues have been resolved. In particular, Element now
1120 has an hasAttributes method, and the handling of namespaces was
1121 improved.
1122
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001123- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1124 getting information about live Python code, and pydoc.py, a module
1125 for interactively converting docstrings to HTML or text.
1126 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001127 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001128 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1129 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001130
Tim Peters1eff7962001-03-01 02:31:33 +00001131- New library module difflib.py, primarily packaging the SequenceMatcher
1132 class at the heart of the popular ndiff.py file-comparison tool.
1133
1134- doctest.py (a framework for verifying Python code examples in docstrings)
1135 is now part of the std library.
1136
Tim Petersd66595f2001-02-04 03:09:53 +00001137Windows changes
1138
Guido van Rossume3955a82001-03-02 14:05:59 +00001139- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1140 small GUI that lets you browse the module docstrings using your
1141 default web browser.
1142
Tim Peters1eff7962001-03-01 02:31:33 +00001143- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1144 Platforms) is implemented. See
1145
1146 http://python.sourceforge.net/peps/pep-0235.html
1147
1148 for full details, especially the "Current Lower-Left Semantics" section.
1149 The new Windows import rules are simpler than before:
1150
1151 A. If the PYTHONCASEOK environment variable exists, same as
1152 before: silently accept the first case-insensitive match of any
1153 kind; raise ImportError if none found.
1154
1155 B. Else search sys.path for the first case-sensitive match; raise
1156 ImportError if none found.
1157
1158 The same rules have been implented on other platforms with case-
1159 insensitive but case-preserving filesystems too (including Cygwin, and
1160 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001161
Tim Peters25a9ce32001-02-19 07:06:36 +00001162- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1163 what it's supposed to do (and does do under NT and 2000) via direct
1164 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001165 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001166 all Win9x systems before.
1167
Tim Peters1eff7962001-03-01 02:31:33 +00001168- Build: Subproject _test (effectively) renamed to _testcapi.
1169
Tim Peters2fe289a2001-03-01 22:19:38 +00001170New platforms
1171
1172- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1173 Thanks to Steven Majewski!
1174
1175- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1176 Tishler!
1177
Guido van Rossum9089b272001-03-02 06:49:50 +00001178- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1179 Schwertberger! See RISCOS/README for more information -- it seems
1180 that because of the bizarre filename conventions on RISCOS, no port
1181 to that platform is easy. Note that the new variable os.endsep is
1182 silently supported in order to make life easier on this platform,
1183 but we don't advertise it because it's not worth for most folks to
1184 care about RISCOS portability.
1185
Tim Peters25a9ce32001-02-19 07:06:36 +00001186
Tim Petersd7b5e882001-01-25 03:36:26 +00001187What's New in Python 2.1 alpha 2?
1188=================================
Tim Peters40ead762001-01-27 05:35:26 +00001189
Tim Petersd7b5e882001-01-25 03:36:26 +00001190Core language, builtins, and interpreter
1191
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001192- Scopes nest. If a name is used in a function or class, but is not
1193 local, the definition in the nearest enclosing function scope will
1194 be used. One consequence of this change is that lambda statements
1195 could reference variables in the namespaces where the lambda is
1196 defined. In some unusual cases, this change will break code.
1197
1198 In all previous version of Python, names were resolved in exactly
1199 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001200 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001201 function A is defined within a function B, the names bound in B are
1202 not visible in A. The new rules make names bound in B visible in A,
1203 unless A contains a name binding that hides the binding in B.
1204
1205 Section 4.1 of the reference manual describes the new scoping rules
1206 in detail. The test script in Lib/test/test_scope.py demonstrates
1207 some of the effects of the change.
1208
1209 The new rules will cause existing code to break if it defines nested
1210 functions where an outer function has local variables with the same
1211 name as globals or builtins used by the inner function. Example:
1212
1213 def munge(str):
1214 def helper(x):
1215 return str(x)
1216 if type(str) != type(''):
1217 str = helper(str)
1218 return str.strip()
1219
1220 Under the old rules, the name str in helper() is bound to the
1221 builtin function str(). Under the new rules, it will be bound to
1222 the argument named str and an error will occur when helper() is
1223 called.
1224
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001225- The compiler will report a SyntaxError if "from ... import *" occurs
1226 in a function or class scope. The language reference has documented
1227 that this case is illegal, but the compiler never checked for it.
1228 The recent introduction of nested scope makes the meaning of this
1229 form of name binding ambiguous. In a future release, the compiler
1230 may allow this form when there is no possibility of ambiguity.
1231
Tim Peters40ead762001-01-27 05:35:26 +00001232- repr(string) is easier to read, now using hex escapes instead of octal,
1233 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1234
1235 >>> "\texample \r\n" + chr(0) + chr(255)
1236 '\texample \r\n\x00\xff' # in 2.1
1237 '\011example \015\012\000\377' # in 2.0
1238
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001239- Functions are now compared and hashed by identity, not by value, since
1240 the func_code attribute is writable.
1241
Fred Drakefb9d7122001-02-01 20:00:40 +00001242- Weak references (PEP 205) have been added. This involves a few
1243 changes in the core, an extension module (_weakref), and a Python
1244 module (weakref). The weakref module is the public interface. It
1245 includes support for "explicit" weak references, proxy objects, and
1246 mappings with weakly held values.
1247
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001248- A 'continue' statement can now appear in a try block within the body
1249 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001250 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001251
Tim Petersd7b5e882001-01-25 03:36:26 +00001252Standard library
1253
Barry Warsaw30dbd142001-01-31 22:14:01 +00001254- mailbox.py now has a new class, PortableUnixMailbox which is
1255 identical to UnixMailbox but uses a more portable scheme for
1256 determining From_ separators. Also, the constructors for all the
1257 classes in this module have a new optional `factory' argument, which
1258 is a callable used when new message classes must be instantiated by
1259 the next() method.
1260
Tim Petersd7b5e882001-01-25 03:36:26 +00001261- random.py is now self-contained, and offers all the functionality of
1262 the now-deprecated whrandom.py. See the docs for details. random.py
1263 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001264 and restoring the internal state of the generator; and jumpahead(n),
1265 for quickly forcing the internal state to be the same as if n calls to
1266 random() had been made. The latter is particularly useful for multi-
1267 threaded programs, creating one instance of the random.Random() class for
1268 each thread, then using .jumpahead() to force each instance to use a
1269 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001270
Tim Peters0de88fc2001-02-01 04:59:18 +00001271- random.py's seed() function is new. For bit-for-bit compatibility with
1272 prior releases, use the whseed function instead. The new seed function
1273 addresses two problems: (1) The old function couldn't produce more than
1274 about 2**24 distinct internal states; the new one about 2**45 (the best
1275 that can be done in the Wichmann-Hill generator). (2) The old function
1276 sometimes produced identical internal states when passed distinct
1277 integers, and there was no simple way to predict when that would happen;
1278 the new one guarantees to produce distinct internal states for all
1279 arguments in [0, 27814431486576L).
1280
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001281- The socket module now supports raw packets on Linux. The socket
1282 family is AF_PACKET.
1283
Tim Peters9ea17ac2001-02-02 05:57:15 +00001284- test_capi.py is a start at running tests of the Python C API. The tests
1285 are implemented by the new Modules/_testmodule.c.
1286
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001287- A new extension module, _symtable, provides provisional access to the
1288 internal symbol table used by the Python compiler. A higher-level
1289 interface will be added on top of _symtable in a future release.
1290
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001291- Removed the obsolete soundex module.
1292
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001293- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1294 the isSameNode method; NamedNodeMap the get method.
1295
1296- xml.sax.expatreader supports the lexical handler property; it
1297 generates comment, startCDATA, and endCDATA events.
1298
Tim Petersee826f82001-01-31 19:39:44 +00001299Windows changes
1300
1301- Build procedure: the zlib project is built in a different way that
1302 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001303 the zlib binary used. See PCbuild\readme.txt for details. Your old
1304 zlib-related directories can be deleted; you'll need to download fresh
1305 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001306
Tim Peters9ea17ac2001-02-02 05:57:15 +00001307- Build: New subproject _test for the benefit of test_capi.py (see above).
1308
Tim Petersb16c56f2001-02-02 21:24:51 +00001309- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1310 interface to some Python compiler internals).
1311
1312- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001313 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001314
Tim Petersa3a3a032000-11-30 05:22:44 +00001315What's New in Python 2.1 alpha 1?
1316=================================
1317
1318Core language, builtins, and interpreter
1319
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001320- There is a new Unicode companion to the PyObject_Str() API
1321 called PyObject_Unicode(). It behaves in the same way as the
1322 former, but assures that the returned value is an Unicode object
1323 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001324
Guido van Rossumf98eda02001-01-17 15:54:45 +00001325- The comparison operators support "rich comparison overloading" (PEP
1326 207). C extension types can provide a rich comparison function in
1327 the new tp_richcompare slot in the type object. The cmp() function
1328 and the C function PyObject_Compare() first try the new rich
1329 comparison operators before trying the old 3-way comparison. There
1330 is also a new C API PyObject_RichCompare() (which also falls back on
1331 the old 3-way comparison, but does not constrain the outcome of the
1332 rich comparison to a Boolean result).
1333
1334 The rich comparison function takes two objects (at least one of
1335 which is guaranteed to have the type that provided the function) and
1336 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1337 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1338 object, which may be NotImplemented (in which case the tp_compare
1339 slot function is used as a fallback, if defined).
1340
1341 Classes can overload individual comparison operators by defining one
1342 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001343 __ge__. There are no explicit "reflected argument" versions of
1344 these; instead, __lt__ and __gt__ are each other's reflection,
1345 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1346 reflection (similar at the C level). No other implications are
1347 made; in particular, Python does not assume that == is the Boolean
1348 inverse of !=, or that < is the Boolean inverse of >=. This makes
1349 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001350
1351 Classes or types that want to implement (in)equality tests but not
1352 the ordering operators (i.e. unordered types) should implement ==
1353 and !=, and raise an error for the ordering operators.
1354
Guido van Rossuma88479f2001-01-18 14:28:08 +00001355 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001356 Boolean; e.g. a matrix type might want to return a matrix of bits
1357 for A < B, giving elementwise comparisons. Such types should ensure
1358 that any interpretation of their value in a Boolean context raises
1359 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1360 at the C level) to always raise an exception.
1361
Guido van Rossuma88479f2001-01-18 14:28:08 +00001362- Complex numbers use rich comparisons to define == and != but raise
1363 an exception for <, <=, > and >=. Unfortunately, this also means
1364 that cmp() of two complex numbers raises an exception when the two
1365 numbers differ. Since it is not mathematically meaningful to compare
1366 complex numbers except for equality, I hope that this doesn't break
1367 too much code.
1368
Tim Peters3389f192001-02-18 08:48:49 +00001369- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001370 not defined by the language, other than that it's arbitrary but
1371 consistent (see the Reference Manual). An implementation detail changed
1372 in 2.1a1 such that None now compares less than any other object. Code
1373 relying on this new behavior (like code that relied on the previous
1374 behavior) does so at its own risk.
1375
Barry Warsaw573b5412001-01-15 20:43:18 +00001376- Functions and methods now support getting and setting arbitrarily
1377 named attributes (PEP 232). Functions have a new __dict__
1378 (a.k.a. func_dict) which hold the function attributes. Methods get
1379 and set attributes on their underlying im_func. It is a TypeError
1380 to set an attribute on a bound method.
1381
Guido van Rossum051e3352001-01-15 19:11:10 +00001382- The xrange() object implementation has been improved so that
1383 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1384 limitation that in this case len(xrange(sys.maxint)) can't be
1385 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1386 work fine as long as the index i doesn't actually reach 2**31.
1387 (Python uses regular ints for sequence and string indices; fixing
1388 that is much more work.)
1389
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001390- Two changes to from...import:
1391
Guido van Rossumba381232001-02-03 15:06:40 +00001392 1) "from M import X" now works even if (after loading module M)
1393 sys.modules['M'] is not a real module; it's basically a getattr()
1394 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001395
1396 2) "from M import *" now looks for M.__all__ to decide which names to
1397 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1398 filters out names starting with '_' as before. Whether or not
1399 __all__ exists, there's no restriction on the type of M.
1400
Guido van Rossumf61f1662001-01-10 20:13:55 +00001401- File objects have a new method, xreadlines(). This is the fastest
1402 way to iterate over all lines in a file:
1403
1404 for line in file.xreadlines():
1405 ...do something to line...
1406
1407 See the xreadlines module (mentioned below) for how to do this for
1408 other file-like objects.
1409
1410- Even if you don't use file.xreadlines(), you may expect a speedup on
1411 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001412 quite a bit in platform-specific ways: on systems (like Linux) that
1413 support flockfile(), getc_unlocked(), and funlockfile(), those are
1414 used by default. On systems (like Windows) without getc_unlocked(),
1415 a complicated (but still thread-safe) method using fgets() is used by
1416 default.
1417
Tim Petersd52269b2001-01-25 06:23:18 +00001418 You can force use of the fgets() method by #define'ing
1419 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001420 getc_unlocked()).
1421
Tim Petersd52269b2001-01-25 06:23:18 +00001422 You can force fgets() not to be used by #define'ing
1423 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001424 test_bufio.py fails -- and let us know if it does!).
1425
1426- In addition, the fileinput module, while still slower than the other
1427 methods on most platforms, has been sped up too, by using
1428 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001429
1430- Support for run-time warnings has been added, including a new
1431 command line option (-W) to specify the disposition of warnings.
1432 See the description of the warnings module below.
1433
1434- Extensive changes have been made to the coercion code. This mostly
1435 affects extension modules (which can now implement mixed-type
1436 numerical operators without having to use coercion), but
1437 occasionally, in boundary cases the coercion semantics have changed
1438 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001439 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001440 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001441 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001442
Guido van Rossumf98eda02001-01-17 15:54:45 +00001443- In connection with the coercion changes, a new built-in singleton
1444 object, NotImplemented is defined. This can be returned for
1445 operations that wish to indicate they are not implemented for a
1446 particular combination of arguments. From C, this is
1447 Py_NotImplemented.
1448
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001449- The interpreter accepts now bytecode files on the command line even
1450 if they do not have a .pyc or .pyo extension. On Linux, after executing
1451
Martin v. Löwise214baa2001-02-04 22:37:56 +00001452import imp,sys,string
1453magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1454reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1455open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001456
1457 any byte code file can be used as an executable (i.e. as an argument
1458 to execve(2)).
1459
Tim Peters9940b802000-12-01 07:59:35 +00001460- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001461 character. In 1.6 and earlier, they never produced a sign,
1462 and raised an error if the value of the long was too large
1463 to fit in a Python int. In 2.0, they produced a sign if and
1464 only if too large to fit in an int. This was inconsistent
1465 across platforms (because the size of an int varies across
1466 platforms), and inconsistent with hex() and oct(). Example:
1467
1468 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001469 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001470 'ffffffbe' # in 2.0 and before, on 32-bit machines
1471 >>> hex(-0x42L)
1472 '-0x42L' # in all versions of Python
1473
Tim Peters9940b802000-12-01 07:59:35 +00001474 The behavior of %d formats for negative Python longs remains
1475 the same as in 2.0 (although in 1.6 and before, they raised
1476 an error if the long didn't fit in a Python int).
1477
1478 %u formats don't make sense for Python longs, but are allowed
1479 and treated the same as %d in 2.1. In 2.0, a negative long
1480 formatted via %u produced a sign if and only if too large to
1481 fit in an int. In 1.6 and earlier, a negative long formatted
1482 via %u raised an error if it was too big to fit in an int.
1483
Guido van Rossum3661d392000-12-12 22:10:31 +00001484- Dictionary objects have an odd new method, popitem(). This removes
1485 an arbitrary item from the dictionary and returns it (in the form of
1486 a (key, value) pair). This can be useful for algorithms that use a
1487 dictionary as a bag of "to do" items and repeatedly need to pick one
1488 item. Such algorithms normally end up running in quadratic time;
1489 using popitem() they can usually be made to run in linear time.
1490
Tim Peters36cdad12000-12-29 02:06:45 +00001491Standard library
1492
Thomas Woutersfe385252001-01-19 23:16:56 +00001493- In the time module, the time argument to the functions strftime,
1494 localtime, gmtime, asctime and ctime is now optional, defaulting to
1495 the current time (in the local timezone).
1496
Guido van Rossumda91f222001-01-15 16:36:08 +00001497- The ftplib module now defaults to passive mode, which is deemed a
1498 more useful default given that clients are often inside firewalls
1499 these days. Note that this could break if ftplib is used to connect
1500 to a *server* that is inside a firewall, from outside; this is
1501 expected to be a very rare situation. To fix that, you can call
1502 ftp.set_pasv(0).
1503
Martin v. Löwis10a27872001-01-13 09:54:41 +00001504- The module site now treats .pth files not only for path configuration,
1505 but also supports extensions to the initialization code: Lines starting
1506 with import are executed.
1507
Guido van Rossumf61f1662001-01-10 20:13:55 +00001508- There's a new module, warnings, which implements a mechanism for
1509 issuing and filtering warnings. There are some new built-in
1510 exceptions that serve as warning categories, and a new command line
1511 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1512 turns warnings into errors). warnings.warn(message[, category])
1513 issues a warning message; this can also be called from C as
1514 PyErr_Warn(category, message).
1515
1516- A new module xreadlines was added. This exports a single factory
1517 function, xreadlines(). The intention is that this code is the
1518 absolutely fastest way to iterate over all lines in an open
1519 file(-like) object:
1520
1521 import xreadlines
1522 for line in xreadlines.xreadlines(file):
1523 ...do something to line...
1524
1525 This is equivalent to the previous the speed record holder using
1526 file.readlines(sizehint). Note that if file is a real file object
1527 (as opposed to a file-like object), this is equivalent:
1528
1529 for line in file.xreadlines():
1530 ...do something to line...
1531
Tim Peters36cdad12000-12-29 02:06:45 +00001532- The bisect module has new functions bisect_left, insort_left,
1533 bisect_right and insort_right. The old names bisect and insort
1534 are now aliases for bisect_right and insort_right. XXX_right
1535 and XXX_left methods differ in what happens when the new element
1536 compares equal to one or more elements already in the list: the
1537 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001538 right. Code that doesn't care where equal elements end up should
1539 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001540
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001541- The new curses.panel module wraps the panel library that forms part
1542 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1543
Guido van Rossumf61f1662001-01-10 20:13:55 +00001544- The SocketServer module now sets the allow_reuse_address flag by
1545 default in the TCPServer class.
1546
1547- A new function, sys._getframe(), returns the stack frame pointer of
1548 the caller. This is intended only as a building block for
1549 higher-level mechanisms such as string interpolation.
1550
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001551- The pyexpat module supports a number of new handlers, which are
1552 available only in expat 1.2. If invocation of a callback fails, it
1553 will report an additional frame in the traceback. Parser objects
1554 participate now in garbage collection. If expat reports an unknown
1555 encoding, pyexpat will try to use a Python codec; that works only
1556 for single-byte charsets. The parser type objects is exposed as
1557 XMLParserObject.
1558
1559- xml.dom now offers standard definitions for symbolic node type and
1560 exception code constants, and a hierarchy of DOM exceptions. minidom
1561 was adjusted to use them.
1562
1563- The conformance of xml.dom.minidom to the DOM specification was
1564 improved. It detects a number of additional error cases; the
1565 previous/next relationship works even when the tree is modified;
1566 Node supports the normalize() method; NamedNodeMap, DocumentType and
1567 DOMImplementation classes were added; Element supports the
1568 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1569 method.
1570
Guido van Rossumf61f1662001-01-10 20:13:55 +00001571Build issues
1572
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001573- For Unix (and Unix-compatible) builds, configuration and building of
1574 extension modules is now greatly automated. Rather than having to
1575 edit the Modules/Setup file to indicate which modules should be
1576 built and where their include files and libraries are, a
1577 distutils-based setup.py script now takes care of building most
1578 extension modules. All extension modules built this way are built
1579 as shared libraries. Only a few modules that must be linked
1580 statically are still listed in the Setup file; you won't need to
1581 edit their configuration.
1582
1583- Python should now build out of the box on Cygwin. If it doesn't,
1584 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001585
1586- Python now always uses its own (renamed) implementation of getopt()
1587 -- there's too much variation among C library getopt()
1588 implementations.
1589
1590- C++ compilers are better supported; the CXX macro is always set to a
1591 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001592
Tim Petersd92dfe02000-12-12 01:18:41 +00001593Windows changes
1594
1595- select module: By default under Windows, a select() call
1596 can specify no more than 64 sockets. Python now boosts
1597 this Microsoft default to 512. If you need even more than
1598 that, see the MS docs (you'll need to #define FD_SETSIZE
1599 and recompile Python from source).
1600
Guido van Rossumf61f1662001-01-10 20:13:55 +00001601- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1602 subdirectory is no more!
1603
Tim Petersa3a3a032000-11-30 05:22:44 +00001604
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001605What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001606=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001607
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001608Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001609changes are in the file HISTORY. If you are making the jump directly
1610from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1611HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001612
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001613Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1614the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1615http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001616
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001617--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001618
1619======================================================================
1620
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001621What's new in 2.0 (since release candidate 1)?
1622==============================================
1623
1624Standard library
1625
1626- The copy_reg module was modified to clarify its intended use: to
1627 register pickle support for extension types, not for classes.
1628 pickle() will raise a TypeError if it is passed a class.
1629
1630- Fixed a bug in gettext's "normalize and expand" code that prevented
1631 it from finding an existing .mo file.
1632
1633- Restored support for HTTP/0.9 servers in httplib.
1634
Tim Peters989b7b92000-10-16 20:24:53 +00001635- The math module was changed to stop raising OverflowError in case of
1636 underflow, and return 0 instead in underflow cases. Whether Python
1637 used to raise OverflowError in case of underflow was platform-
1638 dependent (it did when the platform math library set errno to ERANGE
1639 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001640
1641- Fixed a bug in StringIO that occurred when the file position was not
1642 at the end of the file and write() was called with enough data to
1643 extend past the end of the file.
1644
1645- Fixed a bug that caused Tkinter error messages to get lost on
1646 Windows. The bug was fixed by replacing direct use of
1647 interp->result with Tcl_GetStringResult(interp).
1648
1649- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1650 redirect response.
1651
1652- Several changes were made to distutils: Some debugging code was
1653 removed from util. Fixed the installer used when an external zip
1654 program (like WinZip) is not found; the source code for this
1655 installer is in Misc/distutils. check_lib() was modified to behave
1656 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1657 test for whether installed modules are on sys.path was changed to
1658 use both normcase() and normpath().
1659
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001660- Several minor bugs were fixed in the xml package (the minidom,
1661 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001662
1663- The regression test driver (regrtest.py) behavior when invoked with
1664 -l changed: It now reports a count of objects that are recognized as
1665 garbage but not freed by the garbage collector.
1666
Tim Peters989b7b92000-10-16 20:24:53 +00001667- The regression test for the math module was changed to test
1668 exceptional behavior when the test is run in verbose mode. Python
1669 cannot yet guarantee consistent exception behavior across platforms,
1670 so the exception part of test_math is run only in verbose mode, and
1671 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001672
1673Internals
1674
1675- PyOS_CheckStack() has been disabled on Win64, where it caused
1676 test_sre to fail.
1677
1678Build issues
1679
1680- Changed compiler flags, so that gcc is always invoked with -Wall and
1681 -Wstrict-prototypes. Users compiling Python with GCC should see
1682 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001683 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001684 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001685
Tim Petersa3a3a032000-11-30 05:22:44 +00001686- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001687
1688Tools and other miscellany
1689
1690- The compiler in Tools/compiler was updated to support the new
1691 language features introduced in 2.0: extended print statement, list
1692 comprehensions, and augmented assignments. The new compiler should
1693 also be backwards compatible with Python 1.5.2; the compiler will
1694 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001695 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001696
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001697What's new in 2.0 release candidate 1 (since beta 2)?
1698=====================================================
1699
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001700What is release candidate 1?
1701
1702We believe that release candidate 1 will fix all known bugs that we
1703intend to fix for the 2.0 final release. This release should be a bit
1704more stable than the previous betas. We would like to see even more
1705widespread testing before the final release, so we are producing this
1706release candidate. The final release will be exactly the same unless
1707any show-stopping (or brown bag) bugs are found by testers of the
1708release candidate.
1709
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001710All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001711to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001712
1713Core language, builtins, and interpreter
1714
1715- A bug that caused crashes when __coerce__ was used with augmented
1716 assignment, e.g. +=, was fixed.
1717
1718- Raise ZeroDivisionError when raising zero to a negative number,
1719 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1720 power operator and the result of math.pow(0.0, -2.0) will vary by
1721 platform. On Linux, it raises a ValueError.
1722
1723- A bug in Unicode string interpolation was fixed that occasionally
1724 caused errors with formats including "%%". For example, the
1725 following expression "%% %s" % u"abc" no longer raises a TypeError.
1726
1727- Compilation of deeply nested expressions raises MemoryError instead
1728 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1729
1730- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1731 rendering them useless. They are now written in binary mode again.
1732
1733Standard library
1734
1735- Keyword arguments are now accepted for most pattern and match object
1736 methods in SRE, the standard regular expression engine.
1737
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001738- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001739 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001740
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001741- Several bugs in the Unicode handling and error handling in _tkinter
1742 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001743
1744- Fix memory management errors in Merge() and Tkapp_Call() routines.
1745
1746- Several changes were made to cStringIO to make it compatible with
1747 the file-like object interface and with StringIO. If operations are
1748 performed on a closed object, an exception is raised. The truncate
1749 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001750 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001751
1752- There were many changes made to the linuxaudiodev module and its
1753 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001754 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001755
1756 Note that this module is named poorly, because it should work
1757 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001758 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001759
1760 The module now raises exceptions when errors occur instead of
1761 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1762 audio) and defines a getptr() method that calls the
1763 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1764
1765- The library_version attribute, introduced in an earlier beta, was
1766 removed because it can not be supported with early versions of the C
1767 readline library, which provides no way to determine the version at
1768 compile-time.
1769
1770- The binascii module is now enabled on Win64.
1771
Tim Peters46446d62000-10-09 21:19:31 +00001772- tokenize.py no longer suffers "recursion depth" errors when parsing
1773 programs with very long string literals.
1774
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001775Internals
1776
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001777- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001778 which is called when the interpreter starts up to determine where
1779 the standard library is installed. These vulnerabilities affect all
1780 previous versions of Python and can be exploited by setting very
1781 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1782 setuid Python script, although use of the wrapper in
1783 Misc/setuid-prog.c will eliminate the vulnerability.
1784
1785- Fixed garbage collection bugs in instance creation that were
1786 triggered when errors occurred during initialization. The solution,
1787 applied in cPickle and in PyInstance_New(), is to call
1788 PyObject_GC_Init() after the initialization of the object's
1789 container attributes is complete.
1790
1791- pyexpat adds definitions of PyModule_AddStringConstant and
1792 PyModule_AddObject if the Python version is less than 2.0, which
1793 provides compatibility with PyXML on Python 1.5.2.
1794
1795- If the platform has a bogus definition for LONG_BIT (the number of
1796 bits in a long), an error will be reported at compile time.
1797
1798- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1799 collection crashes and possibly other, unreported crashes.
1800
1801- Fixed a memory leak in _PyUnicode_Fini().
1802
1803Build issues
1804
1805- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001806 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001807 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001808
1809- The mmap.PAGESIZE constant is now initialized using sysconf when
1810 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1811
1812- The md5 file should now compile on all platforms.
1813
1814- The select module now compiles on platforms that do not define
1815 POLLRDNORM and related constants.
1816
1817- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001818 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001819
Jeremy Hylton10921202000-10-09 18:34:12 +00001820- BeOS: A number of changes were made to the build and installation
1821 process. ar-fake now operates on a directory of object files.
1822 dl_export.h is gone, and its macros now appear on the mwcc command
1823 line during build on PPC BeOS.
1824
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001825- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001826 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001827
1828- Cygwin: Support for shared libraries, Tkinter, and sockets.
1829
1830- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1831
1832Tools and other miscellany
1833
1834- Removed debugging prints from main used with freeze.
1835
Tim Peters46446d62000-10-09 21:19:31 +00001836- IDLE auto-indent no longer crashes when it encounters Unicode
1837 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001838
1839What's new in 2.0 beta 2 (since beta 1)?
1840========================================
1841
1842Core language, builtins, and interpreter
1843
Tim Peters482c0212000-09-26 06:33:09 +00001844- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001845 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001846
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001847- Add -h and -V command line options to print the usage message and
1848 Python version number and exit immediately.
1849
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001850- eval() and exec accept Unicode objects as code parameters.
1851
1852- getattr() and setattr() now also accept Unicode objects for the
1853 attribute name, which are converted to strings using the default
1854 encoding before lookup.
1855
1856- Multiplication on string and Unicode now does proper bounds
1857 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1858 string is too long."
1859
1860- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001861 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001862
Jeremy Hylton1b618592000-09-26 05:32:36 +00001863
1864Standard library and extensions
1865
Guido van Rossum5b08f132001-04-16 02:05:23 +00001866- socket module: the OpenSSL code now adds support for RAND_status()
1867 and EGD (Entropy Gathering Device).
1868
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001869- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001870 argument checking; it still takes no arguments.
1871
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001872- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001873
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001874- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001875
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001876- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001877
1878- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001879 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001880
1881- copy: Copy Unicode objects atomically.
1882
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001883- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001884
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001885- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001886
Fred Drake67233bc2000-09-26 16:40:27 +00001887- dbm: Add get() and setdefault() methods to dbm object. Add constant
1888 `library' to module that names the library used. Added doc strings
1889 and method names to error messages. Uses configure to determine
1890 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
1891 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001892
1893- distutils: Update to version 0.9.3.
1894
1895- dl: Add several dl.RTLD_ constants.
1896
1897- fpectl: Now supported on FreeBSD.
1898
1899- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
1900 found by the collector will be saved in gc.garbage. This is useful
1901 for debugging a program that creates reference cycles.
1902
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001903- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00001904 of HTTP class. Do not close socket on zero-length response. Do not
1905 crash when server sends invalid content-length header.
1906
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001907- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001908
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001909- marshal: When reading a short, sign-extend on platforms where shorts
1910 are bigger than 16 bits. When reading a long, repair the unportable
1911 sign extension that was being done for 64-bit machines. (It assumed
1912 that signed right shift sign-extends.)
1913
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001914- operator: Add contains(), invert(), __invert__() as aliases for
1915 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001916
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001917- os: Add support for popen2() and popen3() on all platforms where
1918 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001919
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001920- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00001921 clicking on a file in Explorer (or passing the file name to the
1922 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001923
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001924- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00001925 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001926
1927- pickle: Now raises ValueError when an invalid pickle that contains
1928 a non-string repr where a string repr was expected. This behavior
1929 matches cPickle.
1930
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001931- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001932
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001933- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001934
1935- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001936 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001937 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001938
1939- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001940 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001941
1942- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00001943 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00001944 few cycles during startup since the first call to
1945 setdefaultencoding() will initialize the codec registry and the
1946 encodings package.
1947
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001948- socket: Support for size hint in readlines() method of object returned
1949 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001950
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001951- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001952 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001953 is followed by whitespace.
1954
Tim Petersa3a3a032000-11-30 05:22:44 +00001955- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001956
1957- struct: Check ranges for bytes and shorts.
1958
1959- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001960 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001961
1962- Tkinter: Image objects are now guaranteed to have unique ids. Set
1963 event.delta to zero if Tk version doesn't support mousewheel.
1964 Removed some debugging prints.
1965
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001966- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001967
Fred Drake67233bc2000-09-26 16:40:27 +00001968- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001969 which works around a bug in Norton AntiVirus 2000 that leads directly
1970 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001971
1972- xml: New version detection code allows PyXML to override standard
1973 XML package if PyXML version is greater than 0.6.1.
1974
Fred Drake64bb3802000-09-26 16:21:35 +00001975- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
1976 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
1977 tree only for nodes which are sufficiently interesting to a specific
1978 application. Does not provide the HTML-specific extensions. Still
1979 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001980
Fred Drake64bb3802000-09-26 16:21:35 +00001981- xml.sax: SAX 2 support for Python, including all the handler
1982 interfaces needed to process XML 1.0 compliant XML. Some
1983 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001984
Fred Drake64bb3802000-09-26 16:21:35 +00001985- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
1986 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001987
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001988
Jeremy Hylton1b618592000-09-26 05:32:36 +00001989C API
1990
1991- Add three new convenience functions for module initialization --
1992 PyModule_AddObject(), PyModule_AddIntConstant(), and
1993 PyModule_AddStringConstant().
1994
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001995- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00001996 removed and add #error to Python.h if NULL isn't defined after
1997 #include of stdio.h.
1998
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001999- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002000 backwards compatibility (at the source level) with old extensions.
2001
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002002- A wrapper API was added for signal() and sigaction(). Instead of
2003 either function, always use PyOS_getsig() to get a signal handler
2004 and PyOS_setsig() to set one. A new convenience typedef
2005 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002006
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002007- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002008 internal data buffer and size of a string object -- or the default
2009 encoded version of a Unicode object.
2010
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002011- PyString_Size() and PyString_AsString() accept Unicode objects.
2012
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002013- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002014 exists). INT_MAX and LONG_MAX will always be defined, even if
2015 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002016
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002017- PyFloat_FromString takes a second argument, pend, that was
2018 effectively useless. It is now officially useless but preserved for
2019 backwards compatibility. If the pend argument is not NULL, *pend is
2020 set to NULL.
2021
2022- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2023 for the attribute name. See note on getattr() above.
2024
2025- A few bug fixes to argument processing for Unicode.
2026 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2027 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2028 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002029 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002030
2031- Py_BuildValue accepts B format (for bgen-generated code).
2032
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002033
Jeremy Hylton1b618592000-09-26 05:32:36 +00002034Internals
2035
2036- On Unix, fix code for finding Python installation directory so that
2037 it works when argv[0] is a relative path.
2038
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002039- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002040 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002041 rather than by generating a copy of the object.
2042
Tim Peters482c0212000-09-26 06:33:09 +00002043- Several of the internal Unicode tables are much smaller now, and
2044 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002045
Jeremy Hylton97693b02000-09-26 17:42:51 +00002046- In the garbage collector: Fixed bug in collection of tuples. Fixed
2047 bug that caused some instances to be removed from the container set
2048 while they were still live. Fixed parsing in gc.set_debug() for
2049 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002050
2051- Fixed refcount problem in instance deallocation that only occurred
2052 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2053
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002054- On Windows, getpythonregpath is now protected against null data in
2055 registry key.
2056
2057- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002058 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002059
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002060
Jeremy Hylton1b618592000-09-26 05:32:36 +00002061Build and platform-specific issues
2062
2063- Better support of GNU Pth via --with-pth configure option.
2064
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002065- Python/C API now properly exposed to dynamically-loaded extension
2066 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002067
2068- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2069 Don't define MS_SYNC to be zero when it is undefined. Added missing
2070 prototypes in posixmodule.c.
2071
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002072- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002073 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002074
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002075- Fix largefile support on older NetBSD systems and OpenBSD by adding
2076 define for TELL64.
2077
2078
2079Tools and other miscellany
2080
2081- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2082
2083- freeze: The modulefinder now works with 2.0 opcodes.
2084
Tim Petersa3a3a032000-11-30 05:22:44 +00002085- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002086 Move hackery of sys.argv until after the Tk instance has been
2087 created, which allows the application-specific Tkinter
2088 initialization to be executed if present; also pass an explicit
2089 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002090
Jeremy Hylton1b618592000-09-26 05:32:36 +00002091
2092What's new in 2.0 beta 1?
2093=========================
2094
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002095Source Incompatibilities
2096------------------------
2097
2098None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2099such as single-argument append(), connect() and bind(), and changes to
2100str(long) and repr(float).
2101
2102
2103Binary Incompatibilities
2104------------------------
2105
2106- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2107with Python 2.0; these extensions will have to be rebuilt for Python
21082.0.
2109
2110- On Windows, attempting to import a third party extension built for
2111Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2112can do about this. Check your PYTHONPATH environment variable!
2113
2114- Python bytecode files (*.pyc and *.pyo) are not compatible between
2115releases.
2116
2117
2118Overview of Changes Since 1.6
2119-----------------------------
2120
2121There are many new modules (including brand new XML support through
2122the xml package, and i18n support through the gettext module); a list
2123of all new modules is included below. Lots of bugs have been fixed.
2124
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002125The process for making major new changes to the language has changed
2126since Python 1.6. Enhancements must now be documented by a Python
2127Enhancement Proposal (PEP) before they can be accepted.
2128
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002129There are several important syntax enhancements, described in more
2130detail below:
2131
2132 - Augmented assignment, e.g. x += 1
2133
2134 - List comprehensions, e.g. [x**2 for x in range(10)]
2135
2136 - Extended import statement, e.g. import Module as Name
2137
2138 - Extended print statement, e.g. print >> file, "Hello"
2139
2140Other important changes:
2141
2142 - Optional collection of cyclical garbage
2143
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002144Python Enhancement Proposal (PEP)
2145---------------------------------
2146
2147PEP stands for Python Enhancement Proposal. A PEP is a design
2148document providing information to the Python community, or describing
2149a new feature for Python. The PEP should provide a concise technical
2150specification of the feature and a rationale for the feature.
2151
2152We intend PEPs to be the primary mechanisms for proposing new
2153features, for collecting community input on an issue, and for
2154documenting the design decisions that have gone into Python. The PEP
2155author is responsible for building consensus within the community and
2156documenting dissenting opinions.
2157
2158The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002159
2160Augmented Assignment
2161--------------------
2162
2163This must have been the most-requested feature of the past years!
2164Eleven new assignment operators were added:
2165
Guido van Rossume905e952000-09-05 12:42:46 +00002166 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002167
2168For example,
2169
2170 A += B
2171
2172is similar to
2173
2174 A = A + B
2175
2176except that A is evaluated only once (relevant when A is something
2177like dict[index].attr).
2178
2179However, if A is a mutable object, A may be modified in place. Thus,
2180if A is a number or a string, A += B has the same effect as A = A+B
2181(except A is only evaluated once); but if a is a list, A += B has the
2182same effect as A.extend(B)!
2183
2184Classes and built-in object types can override the new operators in
2185order to implement the in-place behavior; the not-in-place behavior is
2186used automatically as a fallback when an object doesn't implement the
2187in-place behavior. For classes, the method name is derived from the
2188method name for the corresponding not-in-place operator by inserting
2189an 'i' in front of the name, e.g. __iadd__ implements in-place
2190__add__.
2191
2192Augmented assignment was implemented by Thomas Wouters.
2193
2194
2195List Comprehensions
2196-------------------
2197
2198This is a flexible new notation for lists whose elements are computed
2199from another list (or lists). The simplest form is:
2200
2201 [<expression> for <variable> in <sequence>]
2202
Guido van Rossum56db0952000-09-06 23:34:25 +00002203For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002204This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002205
2206You can also add a condition:
2207
2208 [<expression> for <variable> in <sequence> if <condition>]
2209
2210For example, [w for w in words if w == w.lower()] would yield the list
2211of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002212than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002213
2214You can also have nested for loops and more than one 'if' clause. For
2215example, here's a function that flattens a sequence of sequences::
2216
2217 def flatten(seq):
2218 return [x for subseq in seq for x in subseq]
2219
2220 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2221
2222This prints
2223
2224 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2225
2226List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002227Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002228
2229
2230Extended Import Statement
2231-------------------------
2232
2233Many people have asked for a way to import a module under a different
2234name. This can be accomplished like this:
2235
2236 import foo
2237 bar = foo
2238 del foo
2239
2240but this common idiom gets old quickly. A simple extension of the
2241import statement now allows this to be written as follows:
2242
2243 import foo as bar
2244
2245There's also a variant for 'from ... import':
2246
2247 from foo import bar as spam
2248
2249This also works with packages; e.g. you can write this:
2250
2251 import test.regrtest as regrtest
2252
2253Note that 'as' is not a new keyword -- it is recognized only in this
2254context (this is only possible because the syntax for the import
2255statement doesn't involve expressions).
2256
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002257Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002258
2259
2260Extended Print Statement
2261------------------------
2262
2263Easily the most controversial new feature, this extension to the print
2264statement adds an option to make the output go to a different file
2265than the default sys.stdout.
2266
2267For example, to write an error message to sys.stderr, you can now
2268write:
2269
2270 print >> sys.stderr, "Error: bad dog!"
2271
2272As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002273evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002274
2275 print >> None, "Hello world"
2276
2277is equivalent to
2278
2279 print "Hello world"
2280
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002281Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002282
2283
2284Optional Collection of Cyclical Garbage
2285---------------------------------------
2286
2287Python is now equipped with a garbage collector that can hunt down
2288cyclical references between Python objects. It's no replacement for
2289reference counting; in fact, it depends on the reference counts being
2290correct, and decides that a set of objects belong to a cycle if all
2291their reference counts can be accounted for from their references to
2292each other. This devious scheme was first proposed by Eric Tiedemann,
2293and brought to implementation by Neil Schemenauer.
2294
2295There's a module "gc" that lets you control some parameters of the
2296garbage collection. There's also an option to the configure script
2297that lets you enable or disable the garbage collection. In 2.0b1,
2298it's on by default, so that we (hopefully) can collect decent user
2299experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002300performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002301off by default in the final 2.0 release.
2302
2303
2304Smaller Changes
2305---------------
2306
2307A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2308map(None, seq1, seq2, ...) when the sequences have the same length;
2309i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2310the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002311zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002312
2313sys.version_info is a tuple (major, minor, micro, level, serial).
2314
2315Dictionaries have an odd new method, setdefault(key, default).
2316dict.setdefault(key, default) returns dict[key] if it exists; if not,
2317it sets dict[key] to default and returns that value. Thus:
2318
2319 dict.setdefault(key, []).append(item)
2320
2321does the same work as this common idiom:
2322
2323 if not dict.has_key(key):
2324 dict[key] = []
2325 dict[key].append(item)
2326
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002327There are two new variants of SyntaxError that are raised for
2328indentation-related errors: IndentationError and TabError.
2329
2330Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2331escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002332
2333The limits on the size of expressions and file in Python source code
2334have been raised from 2**16 to 2**32. Previous versions of Python
2335were limited because the maximum argument size the Python VM accepted
2336was 2**16. This limited the size of object constructor expressions,
2337e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2338limit was raised thanks to a patch by Charles Waldman that effectively
2339fixes the problem. It is now much more likely that you will be
2340limited by available memory than by an arbitrary limit in Python.
2341
2342The interpreter's maximum recursion depth can be modified by Python
2343programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2344limit is the maximum number of recursive calls that can be made by
2345Python code. The limit exists to prevent infinite recursion from
2346overflowing the C stack and causing a core dump. The default value is
23471000. The maximum safe value for a particular platform can be found
2348by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002349
2350New Modules and Packages
2351------------------------
2352
2353atexit - for registering functions to be called when Python exits.
2354
2355imputil - Greg Stein's alternative API for writing custom import
2356hooks.
2357
2358pyexpat - an interface to the Expat XML parser, contributed by Paul
2359Prescod.
2360
2361xml - a new package with XML support code organized (so far) in three
2362subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2363would fill a volume. There's a special feature whereby a
2364user-installed package named _xmlplus overrides the standard
2365xmlpackage; this is intended to give the XML SIG a hook to distribute
2366backwards-compatible updates to the standard xml package.
2367
2368webbrowser - a platform-independent API to launch a web browser.
2369
2370
Guido van Rossume905e952000-09-05 12:42:46 +00002371Changed Modules
2372---------------
2373
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002374array -- new methods for array objects: count, extend, index, pop, and
2375remove
2376
2377binascii -- new functions b2a_hex and a2b_hex that convert between
2378binary data and its hex representation
2379
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002380calendar -- Many new functions that support features including control
2381over which day of the week is the first day, returning strings instead
2382of printing them. Also new symbolic constants for days of week,
2383e.g. MONDAY, ..., SUNDAY.
2384
2385cgi -- FieldStorage objects have a getvalue method that works like a
2386dictionary's get method and returns the value attribute of the object.
2387
2388ConfigParser -- The parser object has new methods has_option,
2389remove_section, remove_option, set, and write. They allow the module
2390to be used for writing config files as well as reading them.
2391
2392ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002393optionally support the RFC 959 REST command.
2394
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002395gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002396
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002397httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2398the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002399
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002400locale -- implement getdefaultlocale for Win32 and Macintosh
2401
2402marshal -- no longer dumps core when marshaling deeply nested or
2403recursive data structures
2404
2405os -- new functions isatty, seteuid, setegid, setreuid, setregid
2406
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002407os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2408support under Unix.
2409
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002410os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002411
2412os.path -- fix semantics of os.path.commonprefix
2413
2414smtplib -- support for sending very long messages
2415
2416socket -- new function getfqdn()
2417
2418readline -- new functions to read, write and truncate history files.
2419The readline section of the library reference manual contains an
2420example.
2421
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002422select -- add interface to poll system call
2423
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002424shutil -- new copyfileobj function
2425
2426SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2427HTTP server.
2428
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002429Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002430
2431urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002432e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002433
2434whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002435
2436
2437Obsolete Modules
2438----------------
2439
2440None. However note that 1.6 made a whole slew of modules obsolete:
2441stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2442poly, zmod, strop, util, whatsound.
2443
2444
2445Changed, New, Obsolete Tools
2446----------------------------
2447
Tim Peters8b092332000-09-05 20:15:25 +00002448None.
Guido van Rossume905e952000-09-05 12:42:46 +00002449
2450
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002451C-level Changes
2452---------------
2453
2454Several cleanup jobs were carried out throughout the source code.
2455
2456All C code was converted to ANSI C; we got rid of all uses of the
2457Py_PROTO() macro, which makes the header files a lot more readable.
2458
2459Most of the portability hacks were moved to a new header file,
2460pyport.h; several other new header files were added and some old
2461header files were removed, in an attempt to create a more rational set
2462of header files. (Few of these ever need to be included explicitly;
2463they are all included by Python.h.)
2464
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002465Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002466and Win64, especially for the new Intel Itanium processor. Mick also
2467added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002468
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002469The C APIs to return an object's size have been update to consistently
2470use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2471previous versions, the abstract interfaces used PyXXX_Length and the
2472concrete interfaces used PyXXX_Size. The old names,
2473e.g. PyObject_Length, are still available for backwards compatibility
2474at the API level, but are deprecated.
2475
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002476The PyOS_CheckStack function has been implemented on Windows by
2477Fredrik Lundh. It prevents Python from failing with a stack overflow
2478on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002479
2480The GC changes resulted in creation of two new slots on object,
2481tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002482the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002483
2484The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002485C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002486
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002487PyErr_Format has been updated to automatically calculate the size of
2488the buffer needed to hold the formatted result string. This change
2489prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002490
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002491New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002492
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002493PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2494that are the same as their non-Ex counterparts except they take an
2495extra flag argument that tells them to close the file when done.
2496
2497XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002498
Tim Peters8b092332000-09-05 20:15:25 +00002499
2500Windows Changes
2501---------------
2502
2503New popen2/popen3/peopen4 in os module (see Changed Modules above).
2504
2505os.popen is much more usable on Windows 95 and 98. See Microsoft
2506Knowledge Base article Q150956. The Win9x workaround described there
2507is implemented by the new w9xpopen.exe helper in the root of your
2508Python installation. Note that Python uses this internally; it is not
2509a standalone program.
2510
2511Administrator privileges are no longer required to install Python
2512on Windows NT or Windows 2000. If you have administrator privileges,
2513Python's registry info will be written under HKEY_LOCAL_MACHINE.
2514Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002515under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002516uses of Python, but will prevent some advanced uses from working
2517(for example, running a Python script as an NT service, or possibly
2518from CGI).
2519
2520[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2521installer; instead, it installs the needed Tcl/Tk files directly in the
2522Python directory. If you already have a Tcl/Tk installation, this
2523wastes some disk space (about 4 Megs) but avoids problems with
2524conflicting Tcl/Tk installations, and makes it much easier for Python
2525to ensure that Tcl/Tk can find all its files.
2526
2527[This was new in 1.6] The Windows installer now installs by default in
2528\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2529
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002530
2531Updates to the changes between 1.5.2 and 1.6
2532--------------------------------------------
2533
2534The 1.6 NEWS file can't be changed after the release is done, so here
2535is some late-breaking news:
2536
2537New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2538and changes to getlocale() and setlocale().
2539
2540The new module is now enabled per default.
2541
2542It is not true that the encodings codecs cannot be used for normal
2543strings: the string.encode() (which is also present on 8-bit strings
2544!) allows using them for 8-bit strings too, e.g. to convert files from
2545cp1252 (Windows) to latin-1 or vice-versa.
2546
2547Japanese codecs are available from Tamito KAJIYAMA:
2548http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2549
2550
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002551======================================================================