blob: 9a58c384c0f9912e550e37042bbb752b7be58a08 [file] [log] [blame]
Tim Petersb07352e2001-09-08 01:25:47 +00001What's New in Python 2.2a4?
2===========================
3
4Core
5
Tim Peters2c9aa5e2001-09-23 04:06:05 +00006- file.writelines() now accepts any iterable object producing strings.
7
Marc-André Lemburgaefd7662001-09-20 12:59:37 +00008- PyUnicode_FromEncodedObject() now works very much like
9 PyObject_Str(obj) in that it tries to use __str__/tp_str
10 on the object if the object is not a string or buffer. This
11 makes unicode() behave like str() when applied to non-string/buffer
12 objects.
13
Martin v. Löwis2777c022001-09-19 13:47:32 +000014- PyFile_WriteObject now passes Unicode object to the file's write
15 method. As a result, all file-like object which may be the target
16 of a print statement must support Unicode objects, i.e. they must
17 at least convert them into ASCII strings.
18
Tim Peters59c9a642001-09-13 05:38:56 +000019- The builtin file type can be subclassed now. In the usual pattern,
20 "file" is the name of the builtin type, and file() is a new builtin
21 constructor, with the same signature as the builtin open() function.
22 file() is now the preferred way to open a file.
23
Guido van Rossum380bad12001-09-22 17:10:44 +000024- In 2.2a3, *for new-style classes only*, __getattr__ was called for
25 every attribute access. This was confusing because it differed
26 significantly from the behavior of classic classes, where it was
27 only called for missing attributes. Now, __getattr__ is called only
28 if regular attribute access raises AttributeError; to catch *all*
29 attribute access, *for new-style classes only*, you can use
30 __getattribute__. If both are defined, __getattribute__ is called
31 first, and if it raises AttributeError, __getattr__ is called.
32
Guido van Rossum624c8af2001-09-18 15:21:04 +000033- In 2.2a3, __new__ would only see sequential arguments passed to the
34 type in a constructor call; __init__ would see both sequential and
Tim Peters8a9c2842001-09-22 21:30:22 +000035 keyword arguments. This made no sense whatsoever any more, so
Guido van Rossum624c8af2001-09-18 15:21:04 +000036 now both __new__ and __init__ see all arguments.
37
Tim Peters1f47d112001-09-12 23:40:29 +000038- In 2.2a3, hash() applied to an instance of a subclass of str or unicode
39 always returned 0. This has been repaired.
40
41- In 2.2a3, an operation on an instance of a subclass of an immutable type
42 (int, long, float, complex, tuple, str, unicode), where the subtype
43 didn't override the operation (and so the operation was handled by the
44 builtin type), could return that instance instead a value of the base
45 type. For example, if s was of a str sublass type, s[:] returned s
46 as-is. Now it returns a str with the same value as s.
47
Guido van Rossum624c8af2001-09-18 15:21:04 +000048- Applications using Jim Fulton's ExtensionClass module can now safely
49 be used with Python 2.2. In particular, Zope 2.4.1 now works with
50 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
51 examples also work again.
52
53- Thread scheduling on Solaris should be improved; it is no longer
54 necessary to insert a small sleep at the start of a thread in order
55 to let other runnable threads be scheduled.
56
Tim Petersb07352e2001-09-08 01:25:47 +000057Library
58
Tim Peters8a9c2842001-09-22 21:30:22 +000059- difflib.ndiff() and difflib.Differ.compare() are generators now. This
60 restores the ability of Tools/scripts/ndiff.py to start producing output
61 before the entire comparison is complete.
62
Barry Warsaw58b072d2001-09-22 04:44:21 +000063- StringIO.StringIO instances and cStringIO.StringIO instances support
64 iteration just like file objects (i.e. their .readline() method is
65 called for each iteration until it returns an empty string).
66
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +000067- The codecs module has grown four new helper APIs to access
68 builtin codecs: getencoder(), getdecoder(), getreader(),
69 getwriter().
70
Guido van Rossum624c8af2001-09-18 15:21:04 +000071- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
72 simplifies writing XML RPC servers.
73
74- os.path.realpath(): a new function that returns the absoute pathname
75 after interpretation of symbolic links. On non-Unix systems, this
76 is an alias for os.path.abspath().
77
Tim Peters16a77ad2001-09-08 04:00:12 +000078- operator.indexOf() (PySequence_Index() in the C API) now works with any
79 iterable object.
80
Guido van Rossum624c8af2001-09-18 15:21:04 +000081- smtplib now supports various authentication and security features of
82 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +000083
Guido van Rossum624c8af2001-09-18 15:21:04 +000084- hmac: a new module implementing keyed hashing for message
85 authentication.
86
87- mimetypes now recognizes more extensions and file types. At the
88 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +000089
Guido van Rossum624c8af2001-09-18 15:21:04 +000090- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +000091 Python 2.2 bytecode generation. It has also been promoted from a
92 Tool to a standard library package. (Tools/compiler still exists as
93 a sample driver.)
94
95- pydoc and inspect are now aware of new-style classes;
96 e.g. help(list) at the interactive prompt now shows proper
97 documentation for all operations on list objects.
98
99Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000100
Tim Petersb07352e2001-09-08 01:25:47 +0000101Build
102
Guido van Rossum624c8af2001-09-18 15:21:04 +0000103- Large file support (LFS) is now automatic when the platform supports
104 it; no more manual configuration tweaks are needed. On Linux, at
105 least, it's possible to have a system whose C library supports large
106 files but whose kernel doesn't; in this case, large file support is
107 still enabled but doesn't do you any good unless you upgrade your
108 kernel or share your Python executable with another system whose
109 kernel has large file support.
110
111- The configure script now supplies plausible defaults in a
112 cross-compilation environment. This doesn't mean that the supplied
113 values are always correct, or that cross-compilation now works
114 flawlessly -- but it's a first step (and it shuts up most of
115 autoconf's warnings about AC_TRY_RUN).
116
117- The Unix build is now a bit less chatty, courtesy of the parser
118 generator. The build is completely silent (except for errors) when
119 using "make -s", thanks to a -q option to setup.py.
120
Tim Petersb07352e2001-09-08 01:25:47 +0000121C API
122
Guido van Rossum624c8af2001-09-18 15:21:04 +0000123- The "structmember" API now supports some new flag bits to deny read
124 and/or write access to attributes in restricted execution mode.
125
Tim Petersb07352e2001-09-08 01:25:47 +0000126New platforms
127
Guido van Rossum624c8af2001-09-18 15:21:04 +0000128- Compaq's iPAQ handheld, running the "familiar" Linux distribution
129 (http://familiar.handhelds.org).
130
Tim Petersb07352e2001-09-08 01:25:47 +0000131Tests
132
Tim Peters8a9c2842001-09-22 21:30:22 +0000133- The "classic" standard tests, which work by comparing stdout to
134 an expected-output file under Lib/test/output/, no longer stop at
135 the first mismatch. Instead the test is run to completion, and a
136 variant of ndiff-style comparison is used to report all differences.
137 This is much easier to understand than the previous style of reporting.
138
139- The unittest-based standard tests now use regrtest's test_main()
140 convention, instead of running as a side-effect of merely being
141 imported. This allows these tests to be run in more natural and
142 flexible ways as unittests, outside the regrtest framework.
143
144- regrtest.py is much better integrated with unittest and doctest now,
145 especially in regard to reporting errors.
146
Tim Petersb07352e2001-09-08 01:25:47 +0000147Windows
148
Guido van Rossum624c8af2001-09-18 15:21:04 +0000149- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000150 that support it (NTFS under Windows 2000). See "What's New in
151 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000152
Tim Petersb07352e2001-09-08 01:25:47 +0000153
Tim Petersedc99312001-08-22 21:36:50 +0000154What's New in Python 2.2a3?
155===========================
156
157Core
158
Tim Peters9fffa3e2001-09-04 05:14:19 +0000159- Conversion of long to float now raises OverflowError if the long is too
160 big to represent as a C double.
161
Tim Peters32f453e2001-09-03 08:35:41 +0000162- The 3-argument builtin pow() no longer allows a third non-None argument
163 if either of the first two arguments is a float, or if both are of
164 integer types and the second argument is negative (in which latter case
165 the arguments are converted to float, so this is really the same
166 restriction).
167
Tim Peters5d2b77c2001-09-03 05:47:38 +0000168- The builtin dir() now returns more information, and sometimes much
169 more, generally naming all attributes of an object, and all attributes
170 reachable from the object via its class, and from its class's base
171 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
172 an empty list. In 2.2a3,
173
174 >>> dir([])
175 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
176 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
177 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
178 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
179 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
180 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
181 'reverse', 'sort']
182
183 dir(module) continues to return only the module's attributes, though.
184
Tim Petersbdee63f2001-09-02 03:40:59 +0000185- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000186 than raising OverflowError. This is a partial implementation of PEP
187 237. You can use -Wdefault::OverflowWarning to enable a warning for
188 this situation, and -Werror::OverflowWarning to revert to the old
189 OverflowError exception.
190
Guido van Rossum61c345f2001-09-04 03:26:15 +0000191- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000192 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000193 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
194 -Qold, meaning the / operator has its classic meaning and no
195 warnings are issued. Using -Qwarn issues a run-time warning about
196 all uses of classic division for int and long arguments; -Qwarnall
197 also warns about classic division for float and complex arguments
198 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
199 new division by default, but only in the __main__ module. You can
200 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
201 __main__ module new division, and warns about classic division
202 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000203
Tim Petersbdee63f2001-09-02 03:40:59 +0000204- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000205 long, float, str, unicode, and tuple. (The types complex, list and
206 dictionary can also be subclassed; this was introduced earlier.)
207 Note that restrictions apply when subclassing immutable built-in
208 types: you can only affect the value of the instance by overloading
209 __new__. You can add mutable attributes, and the subclass instances
210 will have a __dict__ attribute, but you cannot change the "value"
211 (as implemented by the base class) of an immutable subclass instance
212 once it is created.
213
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000214- The dictionary constructor now takes an optional argument, a
215 mapping-like object, and initializes the dictionary from its
216 (key, value) pairs.
217
Tim Petersbdee63f2001-09-02 03:40:59 +0000218- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000219 "cooperative super calls" in a multiple inheritance setting. For an
220 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
221
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000222- A new built-in type, property, has been added. This enables the
223 creation of "properties". These are attributes implemented by
224 getter and setter functions (or only one of these for read-only or
225 write-only attributes), without the need to override __getattr__.
226 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000227
Tim Petersbdee63f2001-09-02 03:40:59 +0000228- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000229 liberalized, to allow leading zeroes. Examples of literals now
230 legal that were SyntaxErrors before:
231
232 00.0 0e3 0100j 07.5 00000000000000000008.
233
Tim Petersbdee63f2001-09-02 03:40:59 +0000234- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000235 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
236
Tim Petersedc99312001-08-22 21:36:50 +0000237Library
238
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000239- telnetlib includes symbolic names for the options, and support for
240 setting an option negotiation callback.
241
Tim Petersa40c7932001-09-05 22:36:56 +0000242- The new C standard no longer requires that math libraries set errno to
243 ERANGE on overflow. For platform libraries that exploit this new
244 freedom, Python's overflow-checking was wholly broken. A new overflow-
245 checking scheme attempts to repair that, but may not be reliable on all
246 platforms (C doesn't seem to provide anything both useful and portable
247 in this area anymore).
248
Martin v. Löwis44f86962001-09-05 13:44:54 +0000249- Asynchronous timeout actions are available through the new class
250 threading.Timer.
251
Tim Peters78526162001-09-05 00:53:45 +0000252- math.log and math.log10 now return sensible results for even huge
253 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
254
Tim Petersbdee63f2001-09-02 03:40:59 +0000255- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000256 currently held. See the docs for the imp module.
257
Tim Petersbdee63f2001-09-02 03:40:59 +0000258- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000259 dumps containing ints written on platforms where Python ints are 8 bytes.
260 When read on a box where Python ints are 4 bytes, such values are
261 converted to Python longs.
262
Tim Petersbdee63f2001-09-02 03:40:59 +0000263- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000264 code objects is no longer allowed. This plugs a security hole.
265
Steve Purcell6091cd62001-09-06 16:05:17 +0000266- unittest.TestResult instances no longer store references to tracebacks
267 generated by test failures. This prevents unexpected dangling references
268 to objects that should be garbage collected between tests.
269
Tim Petersedc99312001-08-22 21:36:50 +0000270Tools
271
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000272- Tools/scripts/fixdiv.py has been added which can be used to fix
273 division operators as per PEP 238.
274
Tim Petersedc99312001-08-22 21:36:50 +0000275Build
276
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000277- If you are an adventurous person using Mac OS X you may want to look at
278 Mac/OSX. There is a Makefile there that will build Python as a real Mac
279 application, which can be used for experimenting with Carbon or Cocoa.
280 Discussion of this on pythonmac-sig, please.
281
Tim Peters7eea37e2001-09-04 22:08:56 +0000282C API
283
284- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000285
Tim Peters9fffa3e2001-09-04 05:14:19 +0000286- Note that PyLong_AsDouble can fail! This has always been true, but no
287 callers checked for it. It's more likely to fail now, because overflow
288 errors are properly detected now. The proper way to check:
289
290 double x = PyLong_AsDouble(some_long_object);
291 if (x == -1.0 && PyErr_Occurred()) {
292 /* The conversion failed. */
293 }
294
Tim Petersbdee63f2001-09-02 03:40:59 +0000295- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000296 compile but will not participate in GC. To upgrade an extension
297 module:
298
299 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000300
Neil Schemenauer4042c692001-08-30 15:38:01 +0000301 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
302 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000303
Neil Schemenauer4042c692001-08-30 15:38:01 +0000304 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
305 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000306
Neil Schemenauer4042c692001-08-30 15:38:01 +0000307 - remove PyGC_HEAD_SIZE from object size calculations
308
309 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
310
Tim Petersbdee63f2001-09-02 03:40:59 +0000311- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000312 These can be used safely to construct string objects from a
313 sprintf-style format string (similar to the format string supported
314 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000315
Tim Petersedc99312001-08-22 21:36:50 +0000316New platforms
317
Tim Petersb7da0902001-09-02 23:01:43 +0000318- Stephen Hansen contributed patches sufficient to get a clean compile
319 under Borland C (Windows), but he reports problems running it and ran
320 out of time to complete the port. Volunteers? Expect a MemoryError
321 when importing the types module; this is probably shallow, and
322 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000323
Tim Petersedc99312001-08-22 21:36:50 +0000324Tests
325
326Windows
327
Tim Peters6e13a562001-09-06 00:32:15 +0000328- Large file support is now enabled on Win32 platforms as well as on
329 Win64. This means that, for example, you can use f.tell() and f.seek()
330 to manipulate files larger than 2 gigabytes (provided you have enough
331 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000332 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
333 filesize limit, and large file support makes no difference there.
334 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
335 NTFS has no practical limit on file size, and files of any size can be
336 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000337
Tim Petersbdee63f2001-09-02 03:40:59 +0000338- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000339 points to command.com (patch from Brian Quinlan).
340
Tim Petersedc99312001-08-22 21:36:50 +0000341
Tim Peters20f51a72001-07-21 02:31:40 +0000342What's New in Python 2.2a2?
343===========================
344
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000345Build
346
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000347- Tim Peters developed a brand new Windows installer using Wise 8.1,
348 generously donated to us by Wise Solutions.
349
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000350- configure supports a new option --enable-unicode, with the values
351 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
352 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000353
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000354- A new configure option --enable-framework builds a Mac OS X framework,
355 which "make frameworkinstall" will install. This provides a starting
356 point for more mac-like functionality, join pythonmac-sig@python.org
357 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000358
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000359- The NeXT platform is no longer supported.
360
361- The `new' module is now statically linked.
362
Tim Peters0afb6092001-08-15 06:06:44 +0000363Tools
364
365- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000366 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000367 the module docstring for details.
368
Tim Peters20f51a72001-07-21 02:31:40 +0000369Tests
370
Tim Peters5e824c32001-08-12 22:25:01 +0000371- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000372 platforms, allowing to give clearer test result output. regrtest
373 also has optional --use/-u switch to run normally disabled tests
374 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000375
Tim Peters20f51a72001-07-21 02:31:40 +0000376- Several new tests in the standard test suite, with special thanks to
377 Nick Mathewson.
378
379Core
380
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000381- The floor division operator // has been added as outlined in PEP
382 238. The / operator still provides classic division (and will until
383 Python 3.0) unless "from __future__ import division" is included, in
384 which case the / operator will provide true division. The operator
385 module provides truediv() and floordiv() functions. Augmented
386 assignment variants are included, as are the equivalent overloadable
387 methods and C API methods. See the PEP for a full discussion:
388 <http://python.sf.net/peps/pep-0238.html>
389
Tim Peters6cd6a822001-08-17 22:11:27 +0000390- Future statements are now effective in simulated interactive shells
391 (like IDLE). This should "just work" by magic, but read Michael
392 Hudson's "Future statements in simulated shells" PEP 264 for full
393 details: <http://python.sf.net/peps/pep-0264.html>.
394
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000395- The type/class unification (PEP 252-253) was integrated into the
396 trunk and is not so tentative any more (the exact specification of
397 some features is still tentative). A lot of work has done on fixing
398 bugs and adding robustness and features (performance still has to
399 come a long way).
400
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000401- Warnings about a mismatch in the Python API during extension import
402 now use the Python warning framework (which makes it possible to
403 write filters for these warnings).
404
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000405- A function's __dict__ (aka func_dict) will now always be a
406 dictionary. It used to be possible to delete it or set it to None,
407 but now both actions raise TypeErrors. It is still legal to set it
408 to a dictionary object. Getting func.__dict__ before any attributes
409 have been assigned now returns an empty dictionary instead of None.
410
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000411- A new command line option, -E, was added which disables the use of
412 all environment variables, or at least those that are specifically
413 significant to Python. Usually those have a name starting with
414 "PYTHON". This was used to fix a problem where the tests fail if
415 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
416 older distribution.
417
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000418Library
419
Tim Peters5e824c32001-08-12 22:25:01 +0000420- New class Differ and new functions ndiff() and restore() in difflib.py.
421 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000422 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000423
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000424- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
425 value using the minimal quoting required for the value; more
426 reliable than using xml.sax.saxutils.escape() for attribute values.
427
428- Readline completion support for cmd.Cmd was added.
429
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000430- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
431
432- Added function threading.BoundedSemaphore()
433
434- Added Ka-Ping Yee's cgitb.py module.
435
436- The `new' module now exposes the CO_xxx flags.
437
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000438New platforms
439
440C API
441
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000442- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
443 which provide a cross-platform implementations for the
444 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
445 the standard sprintf() and vsprintf() C lib APIs, these versions
446 apply bounds checking on the used buffer which enhances protection
447 against buffer overruns.
448
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000449- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000450 and extensions using different Unicode widths is rendered next to
451 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000452 will result in an ImportError. Unicode extensions writers must make
453 sure to check the Unicode width compatibility in their extensions by
454 using at least one of the mangled Unicode APIs in the extension.
455
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000456- Two new flags METH_NOARGS and METH_O are available in method definition
457 tables to simplify implementation of methods with no arguments and a
458 single untyped argument. Calling such methods is more efficient than
459 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
460 deprecated.
461
Tim Petersc1731372001-08-04 08:12:36 +0000462Windows
463
464- "import module" now compiles module.pyw if it exists and nothing else
465 relevant is found.
466
Tim Peters20f51a72001-07-21 02:31:40 +0000467
Guido van Rossum55a78992001-07-17 17:22:32 +0000468What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +0000469===========================
470
471Core
Tim Petersa814db52001-05-14 07:05:58 +0000472
Tim Peters6d6c1a32001-08-02 04:15:00 +0000473- TENTATIVELY, a large amount of code implementing much of what's
474 described in PEP 252 (Making Types Look More Like Classes) and PEP
475 253 (Subtyping Built-in Types) was added. This will be released
476 with Python 2.2a1. Documentation will be provided separately
477 through http://www.python.org/2.2/. The purpose of releasing this
478 with Python 2.2a1 is to test backwards compatibility. It is
479 possible, though not likely, that a decision is made not to release
480 this code as part of 2.2 final, if any serious backwards
481 incompapatibilities are found during alpha testing that cannot be
482 repaired.
483
Guido van Rossum55a78992001-07-17 17:22:32 +0000484- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000485 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000486 more 'yield' statements. See PEP 255. Since this adds a new
487 keyword to the language, this feature must be enabled by including a
488 future statement: "from __future__ import generators" (see PEP 236).
489 Generators will become a standard feature in a future release
490 (probably 2.3). Without this future statement, 'yield' remains an
491 ordinary identifier, but a warning is issued each time it is used.
492 (These warnings currently don't conform to the warnings framework of
493 PEP 230; we intend to fix this in 2.2a2.)
494
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000495- The UTF-16 codec was modified to be more RFC compliant. It will now
496 only remove BOM characters at the start of the string and then
497 only if running in native mode (UTF-16-LE and -BE won't remove a
498 leading BMO character).
499
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000500- Strings now have a new method .decode() to complement the already
501 existing .encode() method. These two methods provide direct access
502 to the corresponding decoders and encoders of the registered codecs.
503
504 To enhance the usability of the .encode() method, the special
505 casing of Unicode object return values was dropped (Unicode objects
506 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000507
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000508 Both methods will now return whatever the codec in charge of the
509 requested encoding returns as object, e.g. Unicode codecs will
510 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
511 will return u"äöü"). This enables codec writer to create codecs
512 for various simple to use conversions.
513
514 New codecs were added to demonstrate these new features (the .encode()
515 and .decode() columns indicate the type of the returned objects):
516
517 Name | .encode() | .decode() | Description
518 ----------------------------------------------------------------------
519 uu | string | string | UU codec (e.g. for email)
520 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000521 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000522 zlib | string | string | zlib compression
523 hex | string | string | 2-byte hex codec
524 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
525
Mark Hammond2a0af792001-05-14 03:09:36 +0000526- Some operating systems now support the concept of a default Unicode
527 encoding for file system operations. Notably, Windows supports 'mbcs'
528 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000529 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000530 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000531
532 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000533 functions that return filenames (such as os.listdir()) to return Python
534 string objects pre-encoded using the default file system encoding for
535 the platform. As this encoding is likely to be different from Python's
536 default encoding, converting this name to a Unicode object before passing
537 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000538 would attempt to use its default encoding (generally ASCII) rather than
539 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000540
Tim Petersa814db52001-05-14 07:05:58 +0000541 In general, this change simply removes surprises when working with
542 Unicode and the file system, making these operations work as you expect,
543 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000544 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000545
Tim Peters61dff2b2001-05-08 15:43:37 +0000546- Float (and complex) literals in source code were evaluated to full
547 precision only when running from a .py file; the same code loaded from a
548 .pyc (or .pyo) file could suffer numeric differences starting at about the
549 12th significant decimal digit. For example, on a machine with IEEE-754
550 floating arithmetic,
551
552 x = 9007199254740992.0
553 print long(x)
554
555 printed 9007199254740992 if run directly from .py, but 9007199254740000
556 if from a compiled (.pyc or .pyo) file. This was due to marshal using
557 str(float) instead of repr(float) when building code objects. marshal
558 now uses repr(float) instead, which should reproduce floats to full
559 machine precision (assuming the platform C float<->string I/O conversion
560 functions are of good quality).
561
562 This may cause floating-point results to change in some cases, and
563 usually for the better, but may also cause numerically unstable
564 algorithms to break.
565
Tim Peters2f228e72001-05-13 00:19:31 +0000566- The implementation of dicts suffers fewer collisions, which has speed
567 benefits. However, the order in which dict entries appear in dict.keys(),
568 dict.values() and dict.items() may differ from previous releases for a
569 given dict. Nothing is defined about this order, so no program should
570 rely on it. Nevertheless, it's easy to write test cases that rely on the
571 order by accident, typically because of printing the str() or repr() of a
572 dict to an "expected results" file. See Lib/test/test_support.py's new
573 sortdict(dict) function for a simple way to display a dict in sorted
574 order.
575
Tim Peters7a3bfc32001-06-12 01:22:22 +0000576- Many other small changes to dicts were made, resulting in faster
577 operation along the most common code paths.
578
Guido van Rossum10315822001-05-01 20:54:30 +0000579- Dictionary objects now support the "in" operator: "x in dict" means
580 the same as dict.has_key(x).
581
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000582- The update() method of dictionaries now accepts generic mapping
583 objects. Specifically the argument object must support the .keys()
584 and __getitem__() methods. This allows you to say, for example,
585 {}.update(UserDict())
586
Guido van Rossum10315822001-05-01 20:54:30 +0000587- Iterators were added; this is a generalized way of providing values
588 to a for loop. See PEP 234. There's a new built-in function iter()
589 to return an iterator. There's a new protocol to get the next value
590 from an iterator using the next() method (in Python) or the
591 tp_iternext slot (in C). There's a new protocol to get iterators
592 using the __iter__() method (in Python) or the tp_iter slot (in C).
593 Iterating (i.e. a for loop) over a dictionary generates its keys.
594 Iterating over a file generates its lines.
595
Tim Petersf553f892001-05-01 20:45:31 +0000596- The following functions were generalized to work nicely with iterator
597 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000598 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000599 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
600 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000601 join() method of strings
602 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000603 'x in y' and 'x not in y' (PySequence_Contains() in C API)
604 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000605 right-hand side of assignment statements with multiple targets, such as
606 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000607
Tim Petersd85e1022001-05-11 21:51:48 +0000608- Accessing module attributes is significantly faster (for example,
609 random.random or os.path or yourPythonModule.yourAttribute).
610
Tim Peterse63415e2001-05-08 04:38:29 +0000611- Comparing dictionary objects via == and != is faster, and now works even
612 if the keys and values don't support comparisons other than ==.
613
Tim Peters95bf9392001-05-10 08:32:44 +0000614- Comparing dictionaries in ways other than == and != is slower: there were
615 insecurities in the dict comparison implementation that could cause Python
616 to crash if the element comparison routines for the dict keys and/or
617 values mutated the dicts. Making the code bulletproof slowed it down.
618
Tim Peterseb28ef22001-06-02 05:27:19 +0000619- Collisions in dicts are resolved via a new approach, which can help
620 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000621 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000622 faster now. Thanks to Christian Tismer for pointing out the cause and
623 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000624
Tim Peters52e155e2001-06-16 05:42:57 +0000625- repr() is much faster for large containers (dict, list, tuple).
626
627
Tim Petersa814db52001-05-14 07:05:58 +0000628Library
629
Fred Drake960fdf92001-07-20 18:38:26 +0000630- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
631 were added to the string module. These a locale-indenpendent
632 constants, unlike letters, lowercase, and uppercase. These are now
633 use in appropriate locations in the standard library.
634
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000635- The flags used in dlopen calls can now be configured using
636 sys.setdlopenflags and queried using sys.getdlopenflags.
637
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000638- Fredrik Lundh's xmlrpclib is now a standard library module. This
639 provides full client-side XML-RPC support. In addition,
640 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
641 one asyncore-based). Thanks to Eric Raymond for the documentation.
642
Guido van Rossum643d3912001-07-05 14:46:25 +0000643- The xrange() object is simplified: it no longer supports slicing,
644 repetition, comparisons, efficient 'in' checking, the tolist()
645 method, or the start, stop and step attributes. See PEP 260.
646
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000647- A new function fnmatch.filter to filter lists of file names was added.
648
Barry Warsawffd674d2001-05-22 16:00:10 +0000649- calendar.py uses month and day names based on the current locale.
650
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000651- strop is now *really* obsolete (this was announced before with 1.6),
652 and issues DeprecationWarning when used (except for the four items
653 that are still imported into string.py).
654
Tim Petersa814db52001-05-14 07:05:58 +0000655- Cookie.py now sorts key+value pairs by key in output strings.
656
657- pprint.isrecursive(object) didn't correctly identify recursive objects.
658 Now it does.
659
Tim Peters95b3f782001-05-14 18:39:41 +0000660- pprint functions now much faster for large containers (tuple, list, dict).
661
Tim Peters7b9542a2001-06-10 23:40:19 +0000662- New 'q' and 'Q' format codes in the struct module, corresponding to C
663 types "long long" and "unsigned long long" (on Windows, __int64). In
664 native mode, these can be used only when the platform C compiler supports
665 these types (when HAVE_LONG_LONG is #define'd by the Python config
666 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000667 In standard mode, 'q' and 'Q' are supported on all platforms, and are
668 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000669
Guido van Rossum83213cc2001-06-12 16:48:52 +0000670- The site module installs a new built-in function 'help' that invokes
671 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
672 it displays a message reminding the user to use 'help()' or
673 'help(object)'.
674
Tim Petersa814db52001-05-14 07:05:58 +0000675Tests
676
677- New test_mutants.py runs dict comparisons where the key and value
678 comparison operators mutute the dicts randomly during comparison. This
679 rapidly causes Python to crash under earlier releases (not for the faint
680 of heart: it can also cause Win9x to freeze or reboot!).
681
682- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000683 pprint.isreadable() return sensible results. Also verifies that simple
684 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000685
Tim Peters4324aa32001-05-28 22:30:08 +0000686C API
687
688- Removed the unused last_is_sticky argument from the internal
689 _PyTuple_Resize(). If this affects you, you were cheating.
690
691
Guido van Rossum55a78992001-07-17 17:22:32 +0000692======================================================================
693
694
Guido van Rossumffe13be2001-04-16 18:46:45 +0000695What's New in Python 2.1 (final)?
696=================================
697
698We only changed a few things since the last release candidate, all in
699Python library code:
700
701- A bug in the locale module was fixed that affected locales which
702 define no grouping for numeric formatting.
703
704- A few bugs in the weakref module's implementations of weak
705 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
706 and the test suite was updated to check for these bugs.
707
708- An old bug in the os.path.walk() function (introduced in Python
709 2.0!) was fixed: a non-existent file would cause an exception
710 instead of being ignored.
711
712- Fixed a few bugs in the new symtable module found by Neil Norwitz's
713 PyChecker.
714
715
Guido van Rossum5b08f132001-04-16 02:05:23 +0000716What's New in Python 2.1c2?
717===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000718
Guido van Rossum5b08f132001-04-16 02:05:23 +0000719A flurry of small changes, and one showstopper fixed in the nick of
720time made it necessary to release another release candidate. The list
721here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000722
Guido van Rossum5b08f132001-04-16 02:05:23 +0000723Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000724
Guido van Rossum5b08f132001-04-16 02:05:23 +0000725- Tim discovered a nasty bug in the dictionary code, caused by
726 PyDict_Next() calling dict_resize(), and the GC code's use of
727 PyDict_Next() violating an assumption in dict_items(). This was
728 fixed with considerable amounts of band-aid, but the net effect is a
729 saner and more robust implementation.
730
731- Made a bunch of symbols static that were accidentally global.
732
733Build and Ports
734
735- The setup.py script didn't check for a new enough version of zlib
736 (1.1.3 is needed). Now it does.
737
738- Changed "make clean" target to also remove shared libraries.
739
740- Added a more general warning about the SGI Irix optimizer to README.
741
742Library
743
744- Fix a bug in urllib.basejoin("http://host", "../file.html") which
745 omitted the slash between host and file.html.
746
747- The mailbox module's _Mailbox class contained a completely broken
748 and undocumented seek() method. Ripped it out.
749
750- Fixed a bunch of typos in various library modules (urllib2, smtpd,
751 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
752
753- Fixed a few last-minute bugs in unittest.
754
755Extensions
756
757- Reverted the patch to the OpenSSL code in socketmodule.c to support
758 RAND_status() and the EGD, and the subsequent patch that tried to
759 fix it for pre-0.9.5 versions; the problem with the patch is that on
760 some systems it issues a warning whenever socket is imported, and
761 that's unacceptable.
762
763Tests
764
765- Fixed the pickle tests to work with "import test.test_pickle".
766
767- Tweaked test_locale.py to actually run the test Windows.
768
769- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
770 not "wb" (which is not a valid mode at all).
771
772- Fix pstats browser crashes. Import readline if it exists to make
773 the user interface nicer.
774
775- Add "import thread" to the top of test modules that import the
776 threading module (test_asynchat and test_threadedtempfile). This
777 prevents test failures caused by a broken threading module resulting
778 from a previously caught failed import.
779
780- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
781 needed on some platforms (e.g. Solaris 8) when the tests are run
782 twice in succession.
783
784- Skip rather than fail test_sunaudiodev if no audio device is found.
785
786
787What's New in Python 2.1c1?
788===========================
789
790This list was significantly updated when 2.1c2 was released; the 2.1c1
791release didn't mention most changes that were actually part of 2.1c1:
792
793Legal
794
795- Copyright was assigned to the Python Software Foundation (PSF) and a
796 PSF license (very similar to the CNRI license) was added.
797
798- The CNRI copyright notice was updated to include 2001.
799
800Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000801
Guido van Rossumc9932722001-04-12 02:31:27 +0000802- After a public outcry, assignment to __debug__ is no longer illegal;
803 instead, a warning is issued. It will become illegal in 2.2.
804
Guido van Rossum5b08f132001-04-16 02:05:23 +0000805- Fixed a core dump with "%#x" % 0, and changed the semantics so that
806 "%#x" now always prepends "0x", even if the value is zero.
807
808- Fixed some nits in the bytecode compiler.
809
810- Fixed core dumps when calling certain kinds of non-functions.
811
812- Fixed various core dumps caused by reference count bugs.
813
814Build and Ports
815
816- Use INSTALL_SCRIPT to install script files.
817
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000818- New port: SCO Unixware 7, by Billy G. Allie.
819
Guido van Rossum5b08f132001-04-16 02:05:23 +0000820- Updated RISCOS port.
821
822- Updated BeOS port and notes.
823
824- Various other porting problems resolved.
825
826Library
827
828- The TERMIOS and SOCKET modules are now truly obsolete and
829 unnecessary. Their symbols are incorporated in the termios and
830 socket modules.
831
832- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
833 better tests for pickling.
834
835- threading: make Condition.wait() robust against KeyboardInterrupt.
836
837- zipfile: add support to zipfile to support opening an archive
838 represented by an open file rather than a file name. Fix bug where
839 the archive was not properly closed. Fixed a bug in this bugfix
840 where flush() was called for a read-only file.
841
842- imputil: added an uninstall() method to the ImportManager.
843
844- Canvas: fixed bugs in lower() and tkraise() methods.
845
846- SocketServer: API change (added overridable close_request() method)
847 so that the TCP server can explicitly close the request.
848
849- pstats: Eric Raymond added a simple interactive statistics browser,
850 invoked when the module is run as a script.
851
852- locale: fixed a problem in format().
853
854- webbrowser: made it work when the BROWSER environment variable has a
855 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
856 KDE 2. Fixed some other nits.
857
858- unittest: changes to allow using a different exception than
859 AssertionError, and added a few more function aliases. Some other
860 small changes.
861
862- urllib, urllib2: fixed redirect problems and a coupleof other nits.
863
864- asynchat: fixed a critical bug in asynchat that slipped through the
865 2.1b2 release. Fixed another rare bug.
866
867- Fix some unqualified except: clauses (always a bad code example).
868
869XML
870
871- pyexpat: new API get_version_string().
872
873- Fixed some minidom bugs.
874
875Extensions
876
877- Fixed a core dump in _weakref. Removed the weakref.mapping()
878 function (it adds nothing to the API).
879
880- Rationalized the use of header files in the readline module, to make
881 it compile (albeit with some warnings) with the very recent readline
882 4.2, without breaking for earlier versions.
883
884- Hopefully fixed a buffering problem in linuxaudiodev.
885
886- Attempted a fix to make the OpenSSL support in the socket module
887 work again with pre-0.9.5 versions of OpenSSL.
888
889Tests
890
891- Added a test case for asynchat and asyncore.
892
893- Removed coupling between tests where one test failing could break
894 another.
895
896Tools
897
898- Ping added an interactive help browser to pydoc, fixed some nits
899 in the rest of the pydoc code, and added some features to his
900 inspect module.
901
902- An updated python-mode.el version 4.1 which integrates Ken
903 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
904 much nicer in XEmacs and Emacs. When stepping through your program
905 with pdb, in either the shell window or the *Python* window, the
906 source file and line will be tracked by an arrow. Very cool!
907
908- IDLE: syntax warnings in interactive mode are changed into errors.
909
910- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +0000911 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +0000912
913- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000914
Barry Warsaw11e89c72001-04-11 20:37:57 +0000915
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000916What's New in Python 2.1 beta 2?
917================================
918
Guido van Rossum053ae352001-03-22 14:17:21 +0000919(Unlisted are many fixed bugs, more documentation, etc.)
920
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000921Core language, builtins, and interpreter
922
Guido van Rossum053ae352001-03-22 14:17:21 +0000923- The nested scopes work (enabled by "from __future__ import
924 nested_scopes") is completed; in particular, the future now extends
925 into code executed through exec, eval() and execfile(), and into the
926 interactive interpreter.
927
928- When calling a base class method (e.g. BaseClass.__init__(self)),
929 this is now allowed even if self is not strictly spoken a class
930 instance (e.g. when using metaclasses or the Don Beaudry hook).
931
932- Slice objects are now comparable but not hashable; this prevents
933 dict[:] from being accepted but meaningless.
934
935- Complex division is now calculated using less braindead algorithms.
936 This doesn't change semantics except it's more likely to give useful
937 results in extreme cases. Complex repr() now uses full precision
938 like float repr().
939
940- sgmllib.py now calls handle_decl() for simple <!...> declarations.
941
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000942- It is illegal to assign to the name __debug__, which is set when the
943 interpreter starts. It is effectively a compile-time constant.
944
945- A warning will be issued if a global statement for a variable
946 follows a use or assignment of that variable.
947
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000948Standard library
949
Guido van Rossum053ae352001-03-22 14:17:21 +0000950- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
951 inspired by JUnit), is now part of the standard library. You now
952 have a choice of two testing frameworks: unittest requires you to
953 write testcases as separate code, doctest gathers them from
954 docstrings. Both approaches have their advantages and
955 disadvantages.
956
957- A new module Tix was added, which wraps the Tix extension library
958 for Tk. With that module, it is not necessary to statically link
959 Tix with _tkinter, since Tix will be loaded with Tcl's "package
960 require" command. See Demo/tix/.
961
962- tzparse.py is now obsolete.
963
964- In gzip.py, the seek() and tell() methods are removed -- they were
965 non-functional anyway, and it's better if callers can test for their
966 existence with hasattr().
967
968Python/C API
969
970- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
971 that's already in the dictionary during a PyDict_Next() iteration.
972 This used to fail occasionally when a dictionary resize operation
973 could be triggered that would rehash all the keys. All other
974 modifications to the dictionary are still off-limits during a
975 PyDict_Next() iteration!
976
977- New extended APIs related to passing compiler variables around.
978
979- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
980 implement isinstance() and issubclass().
981
982- Py_BuildValue() now has a "D" conversion to create a Python complex
983 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000984
Fred Drake4e262a92001-03-22 18:26:47 +0000985- Extensions types which support weak references must now set the
986 field allocated for the weak reference machinery to NULL themselves;
987 this is done to avoid the cost of checking each object for having a
988 weakly referencable type in PyObject_INIT(), since most types are
989 not weakly referencable.
990
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000991- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
992 free variables and cell variables to and from the frame's f_locals.
993
994- Variants of several functions defined in pythonrun.h have been added
995 to support the nested_scopes future statement. The variants all end
996 in Flags and take an extra argument, a PyCompilerFlags *; examples:
997 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
998 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +0000999 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001000
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001001Distutils
1002
1003- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1004 into the release tree.
1005
Tim Peters0e57abf2001-05-02 07:39:38 +00001006- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001007 (an uninstaller, more customization of the installer's display)
1008
1009- from Jack Jansen: added Mac-specific code to generate a dialog for
1010 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001011 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001012 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001013
1014- added 'platforms' and 'keywords' to the set of metadata that can be
1015 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001016
1017- applied patches from Jason Tishler to make the compiler class work with
1018 Cygwin.
1019
1020
Tim Peters2fe289a2001-03-01 22:19:38 +00001021What's New in Python 2.1 beta 1?
1022================================
Tim Petersd66595f2001-02-04 03:09:53 +00001023
1024Core language, builtins, and interpreter
1025
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001026- Following an outcry from the community about the amount of code
1027 broken by the nested scopes feature introduced in 2.1a2, we decided
1028 to make this feature optional, and to wait until Python 2.2 (or at
1029 least 6 months) to make it standard. The option can be enabled on a
1030 per-module basis by adding "from __future__ import nested_scopes" at
1031 the beginning of a module (before any other statements, but after
1032 comments and an optional docstring). See PEP 236 (Back to the
1033 __future__) for a description of the __future__ statement. PEP 227
1034 (Statically Nested Scopes) has been updated to reflect this change,
1035 and to clarify the semantics in a number of endcases.
1036
1037- The nested scopes code, when enabled, has been hardened, and most
1038 bugs and memory leaks in it have been fixed.
1039
1040- Compile-time warnings are now generated for a number of conditions
1041 that will break or change in meaning when nested scopes are enabled:
1042
1043 - Using "from...import *" or "exec" without in-clause in a function
1044 scope that also defines a lambda or nested function with one or
1045 more free (non-local) variables. The presence of the import* or
1046 bare exec makes it impossible for the compiler to determine the
1047 exact set of local variables in the outer scope, which makes it
1048 impossible to determine the bindings for free variables in the
1049 inner scope. To avoid the warning about import *, change it into
1050 an import of explicitly name object, or move the import* statement
1051 to the global scope; to avoid the warning about bare exec, use
1052 exec...in... (a good idea anyway -- there's a possibility that
1053 bare exec will be deprecated in the future).
1054
1055 - Use of a global variable in a nested scope with the same name as a
1056 local variable in a surrounding scope. This will change in
1057 meaning with nested scopes: the name in the inner scope will
1058 reference the variable in the outer scope rather than the global
1059 of the same name. To avoid the warning, either rename the outer
1060 variable, or use a global statement in the inner function.
1061
Neil Schemenauera35c6882001-02-27 04:45:05 +00001062- An optional object allocator has been included. This allocator is
1063 optimized for Python objects and should be faster and use less memory
1064 than the standard system allocator. It is not enabled by default
1065 because of possible thread safety problems. The allocator is only
1066 protected by the Python interpreter lock and it is possible that some
1067 extension modules require a thread safe allocator. The object
1068 allocator can be enabled by providing the "--with-pymalloc" option to
1069 configure.
1070
Tim Petersd66595f2001-02-04 03:09:53 +00001071Standard library
1072
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001073- pyexpat now detects the expat version if expat.h defines it. A
1074 number of additional handlers are provided, which are only available
1075 since expat 1.95. In addition, the methods SetParamEntityParsing and
1076 GetInputContext of Parser objects are available with 1.95.x
1077 only. Parser objects now provide the ordered_attributes and
1078 specified_attributes attributes. A new module expat.model was added,
1079 which offers a number of additional constants if 1.95.x is used.
1080
1081- xml.dom offers the new functions registerDOMImplementation and
1082 getDOMImplementation.
1083
1084- xml.dom.minidom offers a toprettyxml method. A number of DOM
1085 conformance issues have been resolved. In particular, Element now
1086 has an hasAttributes method, and the handling of namespaces was
1087 improved.
1088
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001089- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1090 getting information about live Python code, and pydoc.py, a module
1091 for interactively converting docstrings to HTML or text.
1092 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001093 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001094 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1095 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001096
Tim Peters1eff7962001-03-01 02:31:33 +00001097- New library module difflib.py, primarily packaging the SequenceMatcher
1098 class at the heart of the popular ndiff.py file-comparison tool.
1099
1100- doctest.py (a framework for verifying Python code examples in docstrings)
1101 is now part of the std library.
1102
Tim Petersd66595f2001-02-04 03:09:53 +00001103Windows changes
1104
Guido van Rossume3955a82001-03-02 14:05:59 +00001105- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1106 small GUI that lets you browse the module docstrings using your
1107 default web browser.
1108
Tim Peters1eff7962001-03-01 02:31:33 +00001109- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1110 Platforms) is implemented. See
1111
1112 http://python.sourceforge.net/peps/pep-0235.html
1113
1114 for full details, especially the "Current Lower-Left Semantics" section.
1115 The new Windows import rules are simpler than before:
1116
1117 A. If the PYTHONCASEOK environment variable exists, same as
1118 before: silently accept the first case-insensitive match of any
1119 kind; raise ImportError if none found.
1120
1121 B. Else search sys.path for the first case-sensitive match; raise
1122 ImportError if none found.
1123
1124 The same rules have been implented on other platforms with case-
1125 insensitive but case-preserving filesystems too (including Cygwin, and
1126 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001127
Tim Peters25a9ce32001-02-19 07:06:36 +00001128- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1129 what it's supposed to do (and does do under NT and 2000) via direct
1130 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001131 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001132 all Win9x systems before.
1133
Tim Peters1eff7962001-03-01 02:31:33 +00001134- Build: Subproject _test (effectively) renamed to _testcapi.
1135
Tim Peters2fe289a2001-03-01 22:19:38 +00001136New platforms
1137
1138- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1139 Thanks to Steven Majewski!
1140
1141- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1142 Tishler!
1143
Guido van Rossum9089b272001-03-02 06:49:50 +00001144- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1145 Schwertberger! See RISCOS/README for more information -- it seems
1146 that because of the bizarre filename conventions on RISCOS, no port
1147 to that platform is easy. Note that the new variable os.endsep is
1148 silently supported in order to make life easier on this platform,
1149 but we don't advertise it because it's not worth for most folks to
1150 care about RISCOS portability.
1151
Tim Peters25a9ce32001-02-19 07:06:36 +00001152
Tim Petersd7b5e882001-01-25 03:36:26 +00001153What's New in Python 2.1 alpha 2?
1154=================================
Tim Peters40ead762001-01-27 05:35:26 +00001155
Tim Petersd7b5e882001-01-25 03:36:26 +00001156Core language, builtins, and interpreter
1157
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001158- Scopes nest. If a name is used in a function or class, but is not
1159 local, the definition in the nearest enclosing function scope will
1160 be used. One consequence of this change is that lambda statements
1161 could reference variables in the namespaces where the lambda is
1162 defined. In some unusual cases, this change will break code.
1163
1164 In all previous version of Python, names were resolved in exactly
1165 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001166 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001167 function A is defined within a function B, the names bound in B are
1168 not visible in A. The new rules make names bound in B visible in A,
1169 unless A contains a name binding that hides the binding in B.
1170
1171 Section 4.1 of the reference manual describes the new scoping rules
1172 in detail. The test script in Lib/test/test_scope.py demonstrates
1173 some of the effects of the change.
1174
1175 The new rules will cause existing code to break if it defines nested
1176 functions where an outer function has local variables with the same
1177 name as globals or builtins used by the inner function. Example:
1178
1179 def munge(str):
1180 def helper(x):
1181 return str(x)
1182 if type(str) != type(''):
1183 str = helper(str)
1184 return str.strip()
1185
1186 Under the old rules, the name str in helper() is bound to the
1187 builtin function str(). Under the new rules, it will be bound to
1188 the argument named str and an error will occur when helper() is
1189 called.
1190
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001191- The compiler will report a SyntaxError if "from ... import *" occurs
1192 in a function or class scope. The language reference has documented
1193 that this case is illegal, but the compiler never checked for it.
1194 The recent introduction of nested scope makes the meaning of this
1195 form of name binding ambiguous. In a future release, the compiler
1196 may allow this form when there is no possibility of ambiguity.
1197
Tim Peters40ead762001-01-27 05:35:26 +00001198- repr(string) is easier to read, now using hex escapes instead of octal,
1199 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1200
1201 >>> "\texample \r\n" + chr(0) + chr(255)
1202 '\texample \r\n\x00\xff' # in 2.1
1203 '\011example \015\012\000\377' # in 2.0
1204
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001205- Functions are now compared and hashed by identity, not by value, since
1206 the func_code attribute is writable.
1207
Fred Drakefb9d7122001-02-01 20:00:40 +00001208- Weak references (PEP 205) have been added. This involves a few
1209 changes in the core, an extension module (_weakref), and a Python
1210 module (weakref). The weakref module is the public interface. It
1211 includes support for "explicit" weak references, proxy objects, and
1212 mappings with weakly held values.
1213
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001214- A 'continue' statement can now appear in a try block within the body
1215 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001216 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001217
Tim Petersd7b5e882001-01-25 03:36:26 +00001218Standard library
1219
Barry Warsaw30dbd142001-01-31 22:14:01 +00001220- mailbox.py now has a new class, PortableUnixMailbox which is
1221 identical to UnixMailbox but uses a more portable scheme for
1222 determining From_ separators. Also, the constructors for all the
1223 classes in this module have a new optional `factory' argument, which
1224 is a callable used when new message classes must be instantiated by
1225 the next() method.
1226
Tim Petersd7b5e882001-01-25 03:36:26 +00001227- random.py is now self-contained, and offers all the functionality of
1228 the now-deprecated whrandom.py. See the docs for details. random.py
1229 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001230 and restoring the internal state of the generator; and jumpahead(n),
1231 for quickly forcing the internal state to be the same as if n calls to
1232 random() had been made. The latter is particularly useful for multi-
1233 threaded programs, creating one instance of the random.Random() class for
1234 each thread, then using .jumpahead() to force each instance to use a
1235 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001236
Tim Peters0de88fc2001-02-01 04:59:18 +00001237- random.py's seed() function is new. For bit-for-bit compatibility with
1238 prior releases, use the whseed function instead. The new seed function
1239 addresses two problems: (1) The old function couldn't produce more than
1240 about 2**24 distinct internal states; the new one about 2**45 (the best
1241 that can be done in the Wichmann-Hill generator). (2) The old function
1242 sometimes produced identical internal states when passed distinct
1243 integers, and there was no simple way to predict when that would happen;
1244 the new one guarantees to produce distinct internal states for all
1245 arguments in [0, 27814431486576L).
1246
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001247- The socket module now supports raw packets on Linux. The socket
1248 family is AF_PACKET.
1249
Tim Peters9ea17ac2001-02-02 05:57:15 +00001250- test_capi.py is a start at running tests of the Python C API. The tests
1251 are implemented by the new Modules/_testmodule.c.
1252
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001253- A new extension module, _symtable, provides provisional access to the
1254 internal symbol table used by the Python compiler. A higher-level
1255 interface will be added on top of _symtable in a future release.
1256
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001257- Removed the obsolete soundex module.
1258
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001259- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1260 the isSameNode method; NamedNodeMap the get method.
1261
1262- xml.sax.expatreader supports the lexical handler property; it
1263 generates comment, startCDATA, and endCDATA events.
1264
Tim Petersee826f82001-01-31 19:39:44 +00001265Windows changes
1266
1267- Build procedure: the zlib project is built in a different way that
1268 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001269 the zlib binary used. See PCbuild\readme.txt for details. Your old
1270 zlib-related directories can be deleted; you'll need to download fresh
1271 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001272
Tim Peters9ea17ac2001-02-02 05:57:15 +00001273- Build: New subproject _test for the benefit of test_capi.py (see above).
1274
Tim Petersb16c56f2001-02-02 21:24:51 +00001275- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1276 interface to some Python compiler internals).
1277
1278- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001279 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001280
Tim Petersa3a3a032000-11-30 05:22:44 +00001281What's New in Python 2.1 alpha 1?
1282=================================
1283
1284Core language, builtins, and interpreter
1285
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001286- There is a new Unicode companion to the PyObject_Str() API
1287 called PyObject_Unicode(). It behaves in the same way as the
1288 former, but assures that the returned value is an Unicode object
1289 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001290
Guido van Rossumf98eda02001-01-17 15:54:45 +00001291- The comparison operators support "rich comparison overloading" (PEP
1292 207). C extension types can provide a rich comparison function in
1293 the new tp_richcompare slot in the type object. The cmp() function
1294 and the C function PyObject_Compare() first try the new rich
1295 comparison operators before trying the old 3-way comparison. There
1296 is also a new C API PyObject_RichCompare() (which also falls back on
1297 the old 3-way comparison, but does not constrain the outcome of the
1298 rich comparison to a Boolean result).
1299
1300 The rich comparison function takes two objects (at least one of
1301 which is guaranteed to have the type that provided the function) and
1302 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1303 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1304 object, which may be NotImplemented (in which case the tp_compare
1305 slot function is used as a fallback, if defined).
1306
1307 Classes can overload individual comparison operators by defining one
1308 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001309 __ge__. There are no explicit "reflected argument" versions of
1310 these; instead, __lt__ and __gt__ are each other's reflection,
1311 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1312 reflection (similar at the C level). No other implications are
1313 made; in particular, Python does not assume that == is the Boolean
1314 inverse of !=, or that < is the Boolean inverse of >=. This makes
1315 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001316
1317 Classes or types that want to implement (in)equality tests but not
1318 the ordering operators (i.e. unordered types) should implement ==
1319 and !=, and raise an error for the ordering operators.
1320
Guido van Rossuma88479f2001-01-18 14:28:08 +00001321 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001322 Boolean; e.g. a matrix type might want to return a matrix of bits
1323 for A < B, giving elementwise comparisons. Such types should ensure
1324 that any interpretation of their value in a Boolean context raises
1325 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1326 at the C level) to always raise an exception.
1327
Guido van Rossuma88479f2001-01-18 14:28:08 +00001328- Complex numbers use rich comparisons to define == and != but raise
1329 an exception for <, <=, > and >=. Unfortunately, this also means
1330 that cmp() of two complex numbers raises an exception when the two
1331 numbers differ. Since it is not mathematically meaningful to compare
1332 complex numbers except for equality, I hope that this doesn't break
1333 too much code.
1334
Tim Peters3389f192001-02-18 08:48:49 +00001335- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001336 not defined by the language, other than that it's arbitrary but
1337 consistent (see the Reference Manual). An implementation detail changed
1338 in 2.1a1 such that None now compares less than any other object. Code
1339 relying on this new behavior (like code that relied on the previous
1340 behavior) does so at its own risk.
1341
Barry Warsaw573b5412001-01-15 20:43:18 +00001342- Functions and methods now support getting and setting arbitrarily
1343 named attributes (PEP 232). Functions have a new __dict__
1344 (a.k.a. func_dict) which hold the function attributes. Methods get
1345 and set attributes on their underlying im_func. It is a TypeError
1346 to set an attribute on a bound method.
1347
Guido van Rossum051e3352001-01-15 19:11:10 +00001348- The xrange() object implementation has been improved so that
1349 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1350 limitation that in this case len(xrange(sys.maxint)) can't be
1351 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1352 work fine as long as the index i doesn't actually reach 2**31.
1353 (Python uses regular ints for sequence and string indices; fixing
1354 that is much more work.)
1355
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001356- Two changes to from...import:
1357
Guido van Rossumba381232001-02-03 15:06:40 +00001358 1) "from M import X" now works even if (after loading module M)
1359 sys.modules['M'] is not a real module; it's basically a getattr()
1360 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001361
1362 2) "from M import *" now looks for M.__all__ to decide which names to
1363 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1364 filters out names starting with '_' as before. Whether or not
1365 __all__ exists, there's no restriction on the type of M.
1366
Guido van Rossumf61f1662001-01-10 20:13:55 +00001367- File objects have a new method, xreadlines(). This is the fastest
1368 way to iterate over all lines in a file:
1369
1370 for line in file.xreadlines():
1371 ...do something to line...
1372
1373 See the xreadlines module (mentioned below) for how to do this for
1374 other file-like objects.
1375
1376- Even if you don't use file.xreadlines(), you may expect a speedup on
1377 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001378 quite a bit in platform-specific ways: on systems (like Linux) that
1379 support flockfile(), getc_unlocked(), and funlockfile(), those are
1380 used by default. On systems (like Windows) without getc_unlocked(),
1381 a complicated (but still thread-safe) method using fgets() is used by
1382 default.
1383
Tim Petersd52269b2001-01-25 06:23:18 +00001384 You can force use of the fgets() method by #define'ing
1385 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001386 getc_unlocked()).
1387
Tim Petersd52269b2001-01-25 06:23:18 +00001388 You can force fgets() not to be used by #define'ing
1389 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001390 test_bufio.py fails -- and let us know if it does!).
1391
1392- In addition, the fileinput module, while still slower than the other
1393 methods on most platforms, has been sped up too, by using
1394 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001395
1396- Support for run-time warnings has been added, including a new
1397 command line option (-W) to specify the disposition of warnings.
1398 See the description of the warnings module below.
1399
1400- Extensive changes have been made to the coercion code. This mostly
1401 affects extension modules (which can now implement mixed-type
1402 numerical operators without having to use coercion), but
1403 occasionally, in boundary cases the coercion semantics have changed
1404 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001405 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001406 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001407 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001408
Guido van Rossumf98eda02001-01-17 15:54:45 +00001409- In connection with the coercion changes, a new built-in singleton
1410 object, NotImplemented is defined. This can be returned for
1411 operations that wish to indicate they are not implemented for a
1412 particular combination of arguments. From C, this is
1413 Py_NotImplemented.
1414
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001415- The interpreter accepts now bytecode files on the command line even
1416 if they do not have a .pyc or .pyo extension. On Linux, after executing
1417
Martin v. Löwise214baa2001-02-04 22:37:56 +00001418import imp,sys,string
1419magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1420reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1421open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001422
1423 any byte code file can be used as an executable (i.e. as an argument
1424 to execve(2)).
1425
Tim Peters9940b802000-12-01 07:59:35 +00001426- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001427 character. In 1.6 and earlier, they never produced a sign,
1428 and raised an error if the value of the long was too large
1429 to fit in a Python int. In 2.0, they produced a sign if and
1430 only if too large to fit in an int. This was inconsistent
1431 across platforms (because the size of an int varies across
1432 platforms), and inconsistent with hex() and oct(). Example:
1433
1434 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001435 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001436 'ffffffbe' # in 2.0 and before, on 32-bit machines
1437 >>> hex(-0x42L)
1438 '-0x42L' # in all versions of Python
1439
Tim Peters9940b802000-12-01 07:59:35 +00001440 The behavior of %d formats for negative Python longs remains
1441 the same as in 2.0 (although in 1.6 and before, they raised
1442 an error if the long didn't fit in a Python int).
1443
1444 %u formats don't make sense for Python longs, but are allowed
1445 and treated the same as %d in 2.1. In 2.0, a negative long
1446 formatted via %u produced a sign if and only if too large to
1447 fit in an int. In 1.6 and earlier, a negative long formatted
1448 via %u raised an error if it was too big to fit in an int.
1449
Guido van Rossum3661d392000-12-12 22:10:31 +00001450- Dictionary objects have an odd new method, popitem(). This removes
1451 an arbitrary item from the dictionary and returns it (in the form of
1452 a (key, value) pair). This can be useful for algorithms that use a
1453 dictionary as a bag of "to do" items and repeatedly need to pick one
1454 item. Such algorithms normally end up running in quadratic time;
1455 using popitem() they can usually be made to run in linear time.
1456
Tim Peters36cdad12000-12-29 02:06:45 +00001457Standard library
1458
Thomas Woutersfe385252001-01-19 23:16:56 +00001459- In the time module, the time argument to the functions strftime,
1460 localtime, gmtime, asctime and ctime is now optional, defaulting to
1461 the current time (in the local timezone).
1462
Guido van Rossumda91f222001-01-15 16:36:08 +00001463- The ftplib module now defaults to passive mode, which is deemed a
1464 more useful default given that clients are often inside firewalls
1465 these days. Note that this could break if ftplib is used to connect
1466 to a *server* that is inside a firewall, from outside; this is
1467 expected to be a very rare situation. To fix that, you can call
1468 ftp.set_pasv(0).
1469
Martin v. Löwis10a27872001-01-13 09:54:41 +00001470- The module site now treats .pth files not only for path configuration,
1471 but also supports extensions to the initialization code: Lines starting
1472 with import are executed.
1473
Guido van Rossumf61f1662001-01-10 20:13:55 +00001474- There's a new module, warnings, which implements a mechanism for
1475 issuing and filtering warnings. There are some new built-in
1476 exceptions that serve as warning categories, and a new command line
1477 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1478 turns warnings into errors). warnings.warn(message[, category])
1479 issues a warning message; this can also be called from C as
1480 PyErr_Warn(category, message).
1481
1482- A new module xreadlines was added. This exports a single factory
1483 function, xreadlines(). The intention is that this code is the
1484 absolutely fastest way to iterate over all lines in an open
1485 file(-like) object:
1486
1487 import xreadlines
1488 for line in xreadlines.xreadlines(file):
1489 ...do something to line...
1490
1491 This is equivalent to the previous the speed record holder using
1492 file.readlines(sizehint). Note that if file is a real file object
1493 (as opposed to a file-like object), this is equivalent:
1494
1495 for line in file.xreadlines():
1496 ...do something to line...
1497
Tim Peters36cdad12000-12-29 02:06:45 +00001498- The bisect module has new functions bisect_left, insort_left,
1499 bisect_right and insort_right. The old names bisect and insort
1500 are now aliases for bisect_right and insort_right. XXX_right
1501 and XXX_left methods differ in what happens when the new element
1502 compares equal to one or more elements already in the list: the
1503 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001504 right. Code that doesn't care where equal elements end up should
1505 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001506
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001507- The new curses.panel module wraps the panel library that forms part
1508 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1509
Guido van Rossumf61f1662001-01-10 20:13:55 +00001510- The SocketServer module now sets the allow_reuse_address flag by
1511 default in the TCPServer class.
1512
1513- A new function, sys._getframe(), returns the stack frame pointer of
1514 the caller. This is intended only as a building block for
1515 higher-level mechanisms such as string interpolation.
1516
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001517- The pyexpat module supports a number of new handlers, which are
1518 available only in expat 1.2. If invocation of a callback fails, it
1519 will report an additional frame in the traceback. Parser objects
1520 participate now in garbage collection. If expat reports an unknown
1521 encoding, pyexpat will try to use a Python codec; that works only
1522 for single-byte charsets. The parser type objects is exposed as
1523 XMLParserObject.
1524
1525- xml.dom now offers standard definitions for symbolic node type and
1526 exception code constants, and a hierarchy of DOM exceptions. minidom
1527 was adjusted to use them.
1528
1529- The conformance of xml.dom.minidom to the DOM specification was
1530 improved. It detects a number of additional error cases; the
1531 previous/next relationship works even when the tree is modified;
1532 Node supports the normalize() method; NamedNodeMap, DocumentType and
1533 DOMImplementation classes were added; Element supports the
1534 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1535 method.
1536
Guido van Rossumf61f1662001-01-10 20:13:55 +00001537Build issues
1538
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001539- For Unix (and Unix-compatible) builds, configuration and building of
1540 extension modules is now greatly automated. Rather than having to
1541 edit the Modules/Setup file to indicate which modules should be
1542 built and where their include files and libraries are, a
1543 distutils-based setup.py script now takes care of building most
1544 extension modules. All extension modules built this way are built
1545 as shared libraries. Only a few modules that must be linked
1546 statically are still listed in the Setup file; you won't need to
1547 edit their configuration.
1548
1549- Python should now build out of the box on Cygwin. If it doesn't,
1550 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001551
1552- Python now always uses its own (renamed) implementation of getopt()
1553 -- there's too much variation among C library getopt()
1554 implementations.
1555
1556- C++ compilers are better supported; the CXX macro is always set to a
1557 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001558
Tim Petersd92dfe02000-12-12 01:18:41 +00001559Windows changes
1560
1561- select module: By default under Windows, a select() call
1562 can specify no more than 64 sockets. Python now boosts
1563 this Microsoft default to 512. If you need even more than
1564 that, see the MS docs (you'll need to #define FD_SETSIZE
1565 and recompile Python from source).
1566
Guido van Rossumf61f1662001-01-10 20:13:55 +00001567- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1568 subdirectory is no more!
1569
Tim Petersa3a3a032000-11-30 05:22:44 +00001570
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001571What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001572=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001573
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001574Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001575changes are in the file HISTORY. If you are making the jump directly
1576from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1577HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001578
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001579Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1580the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1581http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001582
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001583--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001584
1585======================================================================
1586
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001587What's new in 2.0 (since release candidate 1)?
1588==============================================
1589
1590Standard library
1591
1592- The copy_reg module was modified to clarify its intended use: to
1593 register pickle support for extension types, not for classes.
1594 pickle() will raise a TypeError if it is passed a class.
1595
1596- Fixed a bug in gettext's "normalize and expand" code that prevented
1597 it from finding an existing .mo file.
1598
1599- Restored support for HTTP/0.9 servers in httplib.
1600
Tim Peters989b7b92000-10-16 20:24:53 +00001601- The math module was changed to stop raising OverflowError in case of
1602 underflow, and return 0 instead in underflow cases. Whether Python
1603 used to raise OverflowError in case of underflow was platform-
1604 dependent (it did when the platform math library set errno to ERANGE
1605 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001606
1607- Fixed a bug in StringIO that occurred when the file position was not
1608 at the end of the file and write() was called with enough data to
1609 extend past the end of the file.
1610
1611- Fixed a bug that caused Tkinter error messages to get lost on
1612 Windows. The bug was fixed by replacing direct use of
1613 interp->result with Tcl_GetStringResult(interp).
1614
1615- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1616 redirect response.
1617
1618- Several changes were made to distutils: Some debugging code was
1619 removed from util. Fixed the installer used when an external zip
1620 program (like WinZip) is not found; the source code for this
1621 installer is in Misc/distutils. check_lib() was modified to behave
1622 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1623 test for whether installed modules are on sys.path was changed to
1624 use both normcase() and normpath().
1625
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001626- Several minor bugs were fixed in the xml package (the minidom,
1627 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001628
1629- The regression test driver (regrtest.py) behavior when invoked with
1630 -l changed: It now reports a count of objects that are recognized as
1631 garbage but not freed by the garbage collector.
1632
Tim Peters989b7b92000-10-16 20:24:53 +00001633- The regression test for the math module was changed to test
1634 exceptional behavior when the test is run in verbose mode. Python
1635 cannot yet guarantee consistent exception behavior across platforms,
1636 so the exception part of test_math is run only in verbose mode, and
1637 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001638
1639Internals
1640
1641- PyOS_CheckStack() has been disabled on Win64, where it caused
1642 test_sre to fail.
1643
1644Build issues
1645
1646- Changed compiler flags, so that gcc is always invoked with -Wall and
1647 -Wstrict-prototypes. Users compiling Python with GCC should see
1648 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001649 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001650 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001651
Tim Petersa3a3a032000-11-30 05:22:44 +00001652- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001653
1654Tools and other miscellany
1655
1656- The compiler in Tools/compiler was updated to support the new
1657 language features introduced in 2.0: extended print statement, list
1658 comprehensions, and augmented assignments. The new compiler should
1659 also be backwards compatible with Python 1.5.2; the compiler will
1660 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001661 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001662
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001663What's new in 2.0 release candidate 1 (since beta 2)?
1664=====================================================
1665
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001666What is release candidate 1?
1667
1668We believe that release candidate 1 will fix all known bugs that we
1669intend to fix for the 2.0 final release. This release should be a bit
1670more stable than the previous betas. We would like to see even more
1671widespread testing before the final release, so we are producing this
1672release candidate. The final release will be exactly the same unless
1673any show-stopping (or brown bag) bugs are found by testers of the
1674release candidate.
1675
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001676All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001677to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001678
1679Core language, builtins, and interpreter
1680
1681- A bug that caused crashes when __coerce__ was used with augmented
1682 assignment, e.g. +=, was fixed.
1683
1684- Raise ZeroDivisionError when raising zero to a negative number,
1685 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1686 power operator and the result of math.pow(0.0, -2.0) will vary by
1687 platform. On Linux, it raises a ValueError.
1688
1689- A bug in Unicode string interpolation was fixed that occasionally
1690 caused errors with formats including "%%". For example, the
1691 following expression "%% %s" % u"abc" no longer raises a TypeError.
1692
1693- Compilation of deeply nested expressions raises MemoryError instead
1694 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1695
1696- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1697 rendering them useless. They are now written in binary mode again.
1698
1699Standard library
1700
1701- Keyword arguments are now accepted for most pattern and match object
1702 methods in SRE, the standard regular expression engine.
1703
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001704- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001705 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001706
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001707- Several bugs in the Unicode handling and error handling in _tkinter
1708 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001709
1710- Fix memory management errors in Merge() and Tkapp_Call() routines.
1711
1712- Several changes were made to cStringIO to make it compatible with
1713 the file-like object interface and with StringIO. If operations are
1714 performed on a closed object, an exception is raised. The truncate
1715 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001716 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001717
1718- There were many changes made to the linuxaudiodev module and its
1719 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001720 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001721
1722 Note that this module is named poorly, because it should work
1723 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001724 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001725
1726 The module now raises exceptions when errors occur instead of
1727 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1728 audio) and defines a getptr() method that calls the
1729 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1730
1731- The library_version attribute, introduced in an earlier beta, was
1732 removed because it can not be supported with early versions of the C
1733 readline library, which provides no way to determine the version at
1734 compile-time.
1735
1736- The binascii module is now enabled on Win64.
1737
Tim Peters46446d62000-10-09 21:19:31 +00001738- tokenize.py no longer suffers "recursion depth" errors when parsing
1739 programs with very long string literals.
1740
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001741Internals
1742
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001743- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001744 which is called when the interpreter starts up to determine where
1745 the standard library is installed. These vulnerabilities affect all
1746 previous versions of Python and can be exploited by setting very
1747 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1748 setuid Python script, although use of the wrapper in
1749 Misc/setuid-prog.c will eliminate the vulnerability.
1750
1751- Fixed garbage collection bugs in instance creation that were
1752 triggered when errors occurred during initialization. The solution,
1753 applied in cPickle and in PyInstance_New(), is to call
1754 PyObject_GC_Init() after the initialization of the object's
1755 container attributes is complete.
1756
1757- pyexpat adds definitions of PyModule_AddStringConstant and
1758 PyModule_AddObject if the Python version is less than 2.0, which
1759 provides compatibility with PyXML on Python 1.5.2.
1760
1761- If the platform has a bogus definition for LONG_BIT (the number of
1762 bits in a long), an error will be reported at compile time.
1763
1764- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1765 collection crashes and possibly other, unreported crashes.
1766
1767- Fixed a memory leak in _PyUnicode_Fini().
1768
1769Build issues
1770
1771- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001772 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001773 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001774
1775- The mmap.PAGESIZE constant is now initialized using sysconf when
1776 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1777
1778- The md5 file should now compile on all platforms.
1779
1780- The select module now compiles on platforms that do not define
1781 POLLRDNORM and related constants.
1782
1783- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001784 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001785
Jeremy Hylton10921202000-10-09 18:34:12 +00001786- BeOS: A number of changes were made to the build and installation
1787 process. ar-fake now operates on a directory of object files.
1788 dl_export.h is gone, and its macros now appear on the mwcc command
1789 line during build on PPC BeOS.
1790
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001791- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001792 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001793
1794- Cygwin: Support for shared libraries, Tkinter, and sockets.
1795
1796- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1797
1798Tools and other miscellany
1799
1800- Removed debugging prints from main used with freeze.
1801
Tim Peters46446d62000-10-09 21:19:31 +00001802- IDLE auto-indent no longer crashes when it encounters Unicode
1803 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001804
1805What's new in 2.0 beta 2 (since beta 1)?
1806========================================
1807
1808Core language, builtins, and interpreter
1809
Tim Peters482c0212000-09-26 06:33:09 +00001810- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001811 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001812
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001813- Add -h and -V command line options to print the usage message and
1814 Python version number and exit immediately.
1815
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001816- eval() and exec accept Unicode objects as code parameters.
1817
1818- getattr() and setattr() now also accept Unicode objects for the
1819 attribute name, which are converted to strings using the default
1820 encoding before lookup.
1821
1822- Multiplication on string and Unicode now does proper bounds
1823 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1824 string is too long."
1825
1826- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001827 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001828
Jeremy Hylton1b618592000-09-26 05:32:36 +00001829
1830Standard library and extensions
1831
Guido van Rossum5b08f132001-04-16 02:05:23 +00001832- socket module: the OpenSSL code now adds support for RAND_status()
1833 and EGD (Entropy Gathering Device).
1834
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001835- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001836 argument checking; it still takes no arguments.
1837
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001838- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001839
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001840- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001841
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001842- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001843
1844- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001845 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001846
1847- copy: Copy Unicode objects atomically.
1848
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001849- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001850
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001851- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001852
Fred Drake67233bc2000-09-26 16:40:27 +00001853- dbm: Add get() and setdefault() methods to dbm object. Add constant
1854 `library' to module that names the library used. Added doc strings
1855 and method names to error messages. Uses configure to determine
1856 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
1857 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001858
1859- distutils: Update to version 0.9.3.
1860
1861- dl: Add several dl.RTLD_ constants.
1862
1863- fpectl: Now supported on FreeBSD.
1864
1865- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
1866 found by the collector will be saved in gc.garbage. This is useful
1867 for debugging a program that creates reference cycles.
1868
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001869- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00001870 of HTTP class. Do not close socket on zero-length response. Do not
1871 crash when server sends invalid content-length header.
1872
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001873- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001874
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001875- marshal: When reading a short, sign-extend on platforms where shorts
1876 are bigger than 16 bits. When reading a long, repair the unportable
1877 sign extension that was being done for 64-bit machines. (It assumed
1878 that signed right shift sign-extends.)
1879
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001880- operator: Add contains(), invert(), __invert__() as aliases for
1881 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001882
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001883- os: Add support for popen2() and popen3() on all platforms where
1884 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001885
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001886- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00001887 clicking on a file in Explorer (or passing the file name to the
1888 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001889
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001890- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00001891 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001892
1893- pickle: Now raises ValueError when an invalid pickle that contains
1894 a non-string repr where a string repr was expected. This behavior
1895 matches cPickle.
1896
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001897- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001898
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001899- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001900
1901- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001902 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001903 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001904
1905- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001906 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001907
1908- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00001909 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00001910 few cycles during startup since the first call to
1911 setdefaultencoding() will initialize the codec registry and the
1912 encodings package.
1913
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001914- socket: Support for size hint in readlines() method of object returned
1915 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001916
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001917- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001918 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001919 is followed by whitespace.
1920
Tim Petersa3a3a032000-11-30 05:22:44 +00001921- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001922
1923- struct: Check ranges for bytes and shorts.
1924
1925- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001926 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001927
1928- Tkinter: Image objects are now guaranteed to have unique ids. Set
1929 event.delta to zero if Tk version doesn't support mousewheel.
1930 Removed some debugging prints.
1931
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001932- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001933
Fred Drake67233bc2000-09-26 16:40:27 +00001934- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001935 which works around a bug in Norton AntiVirus 2000 that leads directly
1936 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001937
1938- xml: New version detection code allows PyXML to override standard
1939 XML package if PyXML version is greater than 0.6.1.
1940
Fred Drake64bb3802000-09-26 16:21:35 +00001941- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
1942 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
1943 tree only for nodes which are sufficiently interesting to a specific
1944 application. Does not provide the HTML-specific extensions. Still
1945 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001946
Fred Drake64bb3802000-09-26 16:21:35 +00001947- xml.sax: SAX 2 support for Python, including all the handler
1948 interfaces needed to process XML 1.0 compliant XML. Some
1949 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001950
Fred Drake64bb3802000-09-26 16:21:35 +00001951- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
1952 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001953
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001954
Jeremy Hylton1b618592000-09-26 05:32:36 +00001955C API
1956
1957- Add three new convenience functions for module initialization --
1958 PyModule_AddObject(), PyModule_AddIntConstant(), and
1959 PyModule_AddStringConstant().
1960
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001961- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00001962 removed and add #error to Python.h if NULL isn't defined after
1963 #include of stdio.h.
1964
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001965- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00001966 backwards compatibility (at the source level) with old extensions.
1967
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001968- A wrapper API was added for signal() and sigaction(). Instead of
1969 either function, always use PyOS_getsig() to get a signal handler
1970 and PyOS_setsig() to set one. A new convenience typedef
1971 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001972
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001973- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00001974 internal data buffer and size of a string object -- or the default
1975 encoded version of a Unicode object.
1976
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001977- PyString_Size() and PyString_AsString() accept Unicode objects.
1978
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001979- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00001980 exists). INT_MAX and LONG_MAX will always be defined, even if
1981 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001982
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001983- PyFloat_FromString takes a second argument, pend, that was
1984 effectively useless. It is now officially useless but preserved for
1985 backwards compatibility. If the pend argument is not NULL, *pend is
1986 set to NULL.
1987
1988- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
1989 for the attribute name. See note on getattr() above.
1990
1991- A few bug fixes to argument processing for Unicode.
1992 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
1993 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
1994 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00001995 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001996
1997- Py_BuildValue accepts B format (for bgen-generated code).
1998
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001999
Jeremy Hylton1b618592000-09-26 05:32:36 +00002000Internals
2001
2002- On Unix, fix code for finding Python installation directory so that
2003 it works when argv[0] is a relative path.
2004
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002005- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002006 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002007 rather than by generating a copy of the object.
2008
Tim Peters482c0212000-09-26 06:33:09 +00002009- Several of the internal Unicode tables are much smaller now, and
2010 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002011
Jeremy Hylton97693b02000-09-26 17:42:51 +00002012- In the garbage collector: Fixed bug in collection of tuples. Fixed
2013 bug that caused some instances to be removed from the container set
2014 while they were still live. Fixed parsing in gc.set_debug() for
2015 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002016
2017- Fixed refcount problem in instance deallocation that only occurred
2018 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2019
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002020- On Windows, getpythonregpath is now protected against null data in
2021 registry key.
2022
2023- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002024 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002025
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002026
Jeremy Hylton1b618592000-09-26 05:32:36 +00002027Build and platform-specific issues
2028
2029- Better support of GNU Pth via --with-pth configure option.
2030
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002031- Python/C API now properly exposed to dynamically-loaded extension
2032 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002033
2034- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2035 Don't define MS_SYNC to be zero when it is undefined. Added missing
2036 prototypes in posixmodule.c.
2037
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002038- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002039 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002040
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002041- Fix largefile support on older NetBSD systems and OpenBSD by adding
2042 define for TELL64.
2043
2044
2045Tools and other miscellany
2046
2047- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2048
2049- freeze: The modulefinder now works with 2.0 opcodes.
2050
Tim Petersa3a3a032000-11-30 05:22:44 +00002051- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002052 Move hackery of sys.argv until after the Tk instance has been
2053 created, which allows the application-specific Tkinter
2054 initialization to be executed if present; also pass an explicit
2055 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002056
Jeremy Hylton1b618592000-09-26 05:32:36 +00002057
2058What's new in 2.0 beta 1?
2059=========================
2060
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002061Source Incompatibilities
2062------------------------
2063
2064None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2065such as single-argument append(), connect() and bind(), and changes to
2066str(long) and repr(float).
2067
2068
2069Binary Incompatibilities
2070------------------------
2071
2072- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2073with Python 2.0; these extensions will have to be rebuilt for Python
20742.0.
2075
2076- On Windows, attempting to import a third party extension built for
2077Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2078can do about this. Check your PYTHONPATH environment variable!
2079
2080- Python bytecode files (*.pyc and *.pyo) are not compatible between
2081releases.
2082
2083
2084Overview of Changes Since 1.6
2085-----------------------------
2086
2087There are many new modules (including brand new XML support through
2088the xml package, and i18n support through the gettext module); a list
2089of all new modules is included below. Lots of bugs have been fixed.
2090
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002091The process for making major new changes to the language has changed
2092since Python 1.6. Enhancements must now be documented by a Python
2093Enhancement Proposal (PEP) before they can be accepted.
2094
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002095There are several important syntax enhancements, described in more
2096detail below:
2097
2098 - Augmented assignment, e.g. x += 1
2099
2100 - List comprehensions, e.g. [x**2 for x in range(10)]
2101
2102 - Extended import statement, e.g. import Module as Name
2103
2104 - Extended print statement, e.g. print >> file, "Hello"
2105
2106Other important changes:
2107
2108 - Optional collection of cyclical garbage
2109
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002110Python Enhancement Proposal (PEP)
2111---------------------------------
2112
2113PEP stands for Python Enhancement Proposal. A PEP is a design
2114document providing information to the Python community, or describing
2115a new feature for Python. The PEP should provide a concise technical
2116specification of the feature and a rationale for the feature.
2117
2118We intend PEPs to be the primary mechanisms for proposing new
2119features, for collecting community input on an issue, and for
2120documenting the design decisions that have gone into Python. The PEP
2121author is responsible for building consensus within the community and
2122documenting dissenting opinions.
2123
2124The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002125
2126Augmented Assignment
2127--------------------
2128
2129This must have been the most-requested feature of the past years!
2130Eleven new assignment operators were added:
2131
Guido van Rossume905e952000-09-05 12:42:46 +00002132 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002133
2134For example,
2135
2136 A += B
2137
2138is similar to
2139
2140 A = A + B
2141
2142except that A is evaluated only once (relevant when A is something
2143like dict[index].attr).
2144
2145However, if A is a mutable object, A may be modified in place. Thus,
2146if A is a number or a string, A += B has the same effect as A = A+B
2147(except A is only evaluated once); but if a is a list, A += B has the
2148same effect as A.extend(B)!
2149
2150Classes and built-in object types can override the new operators in
2151order to implement the in-place behavior; the not-in-place behavior is
2152used automatically as a fallback when an object doesn't implement the
2153in-place behavior. For classes, the method name is derived from the
2154method name for the corresponding not-in-place operator by inserting
2155an 'i' in front of the name, e.g. __iadd__ implements in-place
2156__add__.
2157
2158Augmented assignment was implemented by Thomas Wouters.
2159
2160
2161List Comprehensions
2162-------------------
2163
2164This is a flexible new notation for lists whose elements are computed
2165from another list (or lists). The simplest form is:
2166
2167 [<expression> for <variable> in <sequence>]
2168
Guido van Rossum56db0952000-09-06 23:34:25 +00002169For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002170This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002171
2172You can also add a condition:
2173
2174 [<expression> for <variable> in <sequence> if <condition>]
2175
2176For example, [w for w in words if w == w.lower()] would yield the list
2177of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002178than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002179
2180You can also have nested for loops and more than one 'if' clause. For
2181example, here's a function that flattens a sequence of sequences::
2182
2183 def flatten(seq):
2184 return [x for subseq in seq for x in subseq]
2185
2186 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2187
2188This prints
2189
2190 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2191
2192List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002193Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002194
2195
2196Extended Import Statement
2197-------------------------
2198
2199Many people have asked for a way to import a module under a different
2200name. This can be accomplished like this:
2201
2202 import foo
2203 bar = foo
2204 del foo
2205
2206but this common idiom gets old quickly. A simple extension of the
2207import statement now allows this to be written as follows:
2208
2209 import foo as bar
2210
2211There's also a variant for 'from ... import':
2212
2213 from foo import bar as spam
2214
2215This also works with packages; e.g. you can write this:
2216
2217 import test.regrtest as regrtest
2218
2219Note that 'as' is not a new keyword -- it is recognized only in this
2220context (this is only possible because the syntax for the import
2221statement doesn't involve expressions).
2222
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002223Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002224
2225
2226Extended Print Statement
2227------------------------
2228
2229Easily the most controversial new feature, this extension to the print
2230statement adds an option to make the output go to a different file
2231than the default sys.stdout.
2232
2233For example, to write an error message to sys.stderr, you can now
2234write:
2235
2236 print >> sys.stderr, "Error: bad dog!"
2237
2238As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002239evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002240
2241 print >> None, "Hello world"
2242
2243is equivalent to
2244
2245 print "Hello world"
2246
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002247Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002248
2249
2250Optional Collection of Cyclical Garbage
2251---------------------------------------
2252
2253Python is now equipped with a garbage collector that can hunt down
2254cyclical references between Python objects. It's no replacement for
2255reference counting; in fact, it depends on the reference counts being
2256correct, and decides that a set of objects belong to a cycle if all
2257their reference counts can be accounted for from their references to
2258each other. This devious scheme was first proposed by Eric Tiedemann,
2259and brought to implementation by Neil Schemenauer.
2260
2261There's a module "gc" that lets you control some parameters of the
2262garbage collection. There's also an option to the configure script
2263that lets you enable or disable the garbage collection. In 2.0b1,
2264it's on by default, so that we (hopefully) can collect decent user
2265experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002266performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002267off by default in the final 2.0 release.
2268
2269
2270Smaller Changes
2271---------------
2272
2273A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2274map(None, seq1, seq2, ...) when the sequences have the same length;
2275i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2276the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002277zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002278
2279sys.version_info is a tuple (major, minor, micro, level, serial).
2280
2281Dictionaries have an odd new method, setdefault(key, default).
2282dict.setdefault(key, default) returns dict[key] if it exists; if not,
2283it sets dict[key] to default and returns that value. Thus:
2284
2285 dict.setdefault(key, []).append(item)
2286
2287does the same work as this common idiom:
2288
2289 if not dict.has_key(key):
2290 dict[key] = []
2291 dict[key].append(item)
2292
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002293There are two new variants of SyntaxError that are raised for
2294indentation-related errors: IndentationError and TabError.
2295
2296Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2297escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002298
2299The limits on the size of expressions and file in Python source code
2300have been raised from 2**16 to 2**32. Previous versions of Python
2301were limited because the maximum argument size the Python VM accepted
2302was 2**16. This limited the size of object constructor expressions,
2303e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2304limit was raised thanks to a patch by Charles Waldman that effectively
2305fixes the problem. It is now much more likely that you will be
2306limited by available memory than by an arbitrary limit in Python.
2307
2308The interpreter's maximum recursion depth can be modified by Python
2309programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2310limit is the maximum number of recursive calls that can be made by
2311Python code. The limit exists to prevent infinite recursion from
2312overflowing the C stack and causing a core dump. The default value is
23131000. The maximum safe value for a particular platform can be found
2314by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002315
2316New Modules and Packages
2317------------------------
2318
2319atexit - for registering functions to be called when Python exits.
2320
2321imputil - Greg Stein's alternative API for writing custom import
2322hooks.
2323
2324pyexpat - an interface to the Expat XML parser, contributed by Paul
2325Prescod.
2326
2327xml - a new package with XML support code organized (so far) in three
2328subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2329would fill a volume. There's a special feature whereby a
2330user-installed package named _xmlplus overrides the standard
2331xmlpackage; this is intended to give the XML SIG a hook to distribute
2332backwards-compatible updates to the standard xml package.
2333
2334webbrowser - a platform-independent API to launch a web browser.
2335
2336
Guido van Rossume905e952000-09-05 12:42:46 +00002337Changed Modules
2338---------------
2339
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002340array -- new methods for array objects: count, extend, index, pop, and
2341remove
2342
2343binascii -- new functions b2a_hex and a2b_hex that convert between
2344binary data and its hex representation
2345
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002346calendar -- Many new functions that support features including control
2347over which day of the week is the first day, returning strings instead
2348of printing them. Also new symbolic constants for days of week,
2349e.g. MONDAY, ..., SUNDAY.
2350
2351cgi -- FieldStorage objects have a getvalue method that works like a
2352dictionary's get method and returns the value attribute of the object.
2353
2354ConfigParser -- The parser object has new methods has_option,
2355remove_section, remove_option, set, and write. They allow the module
2356to be used for writing config files as well as reading them.
2357
2358ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002359optionally support the RFC 959 REST command.
2360
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002361gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002362
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002363httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2364the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002365
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002366locale -- implement getdefaultlocale for Win32 and Macintosh
2367
2368marshal -- no longer dumps core when marshaling deeply nested or
2369recursive data structures
2370
2371os -- new functions isatty, seteuid, setegid, setreuid, setregid
2372
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002373os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2374support under Unix.
2375
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002376os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002377
2378os.path -- fix semantics of os.path.commonprefix
2379
2380smtplib -- support for sending very long messages
2381
2382socket -- new function getfqdn()
2383
2384readline -- new functions to read, write and truncate history files.
2385The readline section of the library reference manual contains an
2386example.
2387
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002388select -- add interface to poll system call
2389
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002390shutil -- new copyfileobj function
2391
2392SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2393HTTP server.
2394
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002395Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002396
2397urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002398e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002399
2400whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002401
2402
2403Obsolete Modules
2404----------------
2405
2406None. However note that 1.6 made a whole slew of modules obsolete:
2407stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2408poly, zmod, strop, util, whatsound.
2409
2410
2411Changed, New, Obsolete Tools
2412----------------------------
2413
Tim Peters8b092332000-09-05 20:15:25 +00002414None.
Guido van Rossume905e952000-09-05 12:42:46 +00002415
2416
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002417C-level Changes
2418---------------
2419
2420Several cleanup jobs were carried out throughout the source code.
2421
2422All C code was converted to ANSI C; we got rid of all uses of the
2423Py_PROTO() macro, which makes the header files a lot more readable.
2424
2425Most of the portability hacks were moved to a new header file,
2426pyport.h; several other new header files were added and some old
2427header files were removed, in an attempt to create a more rational set
2428of header files. (Few of these ever need to be included explicitly;
2429they are all included by Python.h.)
2430
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002431Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002432and Win64, especially for the new Intel Itanium processor. Mick also
2433added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002434
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002435The C APIs to return an object's size have been update to consistently
2436use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2437previous versions, the abstract interfaces used PyXXX_Length and the
2438concrete interfaces used PyXXX_Size. The old names,
2439e.g. PyObject_Length, are still available for backwards compatibility
2440at the API level, but are deprecated.
2441
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002442The PyOS_CheckStack function has been implemented on Windows by
2443Fredrik Lundh. It prevents Python from failing with a stack overflow
2444on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002445
2446The GC changes resulted in creation of two new slots on object,
2447tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002448the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002449
2450The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002451C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002452
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002453PyErr_Format has been updated to automatically calculate the size of
2454the buffer needed to hold the formatted result string. This change
2455prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002456
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002457New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002458
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002459PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2460that are the same as their non-Ex counterparts except they take an
2461extra flag argument that tells them to close the file when done.
2462
2463XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002464
Tim Peters8b092332000-09-05 20:15:25 +00002465
2466Windows Changes
2467---------------
2468
2469New popen2/popen3/peopen4 in os module (see Changed Modules above).
2470
2471os.popen is much more usable on Windows 95 and 98. See Microsoft
2472Knowledge Base article Q150956. The Win9x workaround described there
2473is implemented by the new w9xpopen.exe helper in the root of your
2474Python installation. Note that Python uses this internally; it is not
2475a standalone program.
2476
2477Administrator privileges are no longer required to install Python
2478on Windows NT or Windows 2000. If you have administrator privileges,
2479Python's registry info will be written under HKEY_LOCAL_MACHINE.
2480Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002481under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002482uses of Python, but will prevent some advanced uses from working
2483(for example, running a Python script as an NT service, or possibly
2484from CGI).
2485
2486[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2487installer; instead, it installs the needed Tcl/Tk files directly in the
2488Python directory. If you already have a Tcl/Tk installation, this
2489wastes some disk space (about 4 Megs) but avoids problems with
2490conflicting Tcl/Tk installations, and makes it much easier for Python
2491to ensure that Tcl/Tk can find all its files.
2492
2493[This was new in 1.6] The Windows installer now installs by default in
2494\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2495
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002496
2497Updates to the changes between 1.5.2 and 1.6
2498--------------------------------------------
2499
2500The 1.6 NEWS file can't be changed after the release is done, so here
2501is some late-breaking news:
2502
2503New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2504and changes to getlocale() and setlocale().
2505
2506The new module is now enabled per default.
2507
2508It is not true that the encodings codecs cannot be used for normal
2509strings: the string.encode() (which is also present on 8-bit strings
2510!) allows using them for 8-bit strings too, e.g. to convert files from
2511cp1252 (Windows) to latin-1 or vice-versa.
2512
2513Japanese codecs are available from Tamito KAJIYAMA:
2514http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2515
2516
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002517======================================================================