blob: 713eb173c5ba9904992b2614f1ee6d7fa13f7390 [file] [log] [blame]
Tim Petersb07352e2001-09-08 01:25:47 +00001What's New in Python 2.2a4?
2===========================
3
4Core
5
Marc-André Lemburgaefd7662001-09-20 12:59:37 +00006- PyUnicode_FromEncodedObject() now works very much like
7 PyObject_Str(obj) in that it tries to use __str__/tp_str
8 on the object if the object is not a string or buffer. This
9 makes unicode() behave like str() when applied to non-string/buffer
10 objects.
11
Martin v. Löwis2777c022001-09-19 13:47:32 +000012- PyFile_WriteObject now passes Unicode object to the file's write
13 method. As a result, all file-like object which may be the target
14 of a print statement must support Unicode objects, i.e. they must
15 at least convert them into ASCII strings.
16
Tim Peters59c9a642001-09-13 05:38:56 +000017- The builtin file type can be subclassed now. In the usual pattern,
18 "file" is the name of the builtin type, and file() is a new builtin
19 constructor, with the same signature as the builtin open() function.
20 file() is now the preferred way to open a file.
21
Guido van Rossum380bad12001-09-22 17:10:44 +000022- In 2.2a3, *for new-style classes only*, __getattr__ was called for
23 every attribute access. This was confusing because it differed
24 significantly from the behavior of classic classes, where it was
25 only called for missing attributes. Now, __getattr__ is called only
26 if regular attribute access raises AttributeError; to catch *all*
27 attribute access, *for new-style classes only*, you can use
28 __getattribute__. If both are defined, __getattribute__ is called
29 first, and if it raises AttributeError, __getattr__ is called.
30
Guido van Rossum624c8af2001-09-18 15:21:04 +000031- In 2.2a3, __new__ would only see sequential arguments passed to the
32 type in a constructor call; __init__ would see both sequential and
33 positional arguments. This made no sense whatsoever any more, so
34 now both __new__ and __init__ see all arguments.
35
Tim Peters1f47d112001-09-12 23:40:29 +000036- In 2.2a3, hash() applied to an instance of a subclass of str or unicode
37 always returned 0. This has been repaired.
38
39- In 2.2a3, an operation on an instance of a subclass of an immutable type
40 (int, long, float, complex, tuple, str, unicode), where the subtype
41 didn't override the operation (and so the operation was handled by the
42 builtin type), could return that instance instead a value of the base
43 type. For example, if s was of a str sublass type, s[:] returned s
44 as-is. Now it returns a str with the same value as s.
45
Guido van Rossum624c8af2001-09-18 15:21:04 +000046- Applications using Jim Fulton's ExtensionClass module can now safely
47 be used with Python 2.2. In particular, Zope 2.4.1 now works with
48 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
49 examples also work again.
50
51- Thread scheduling on Solaris should be improved; it is no longer
52 necessary to insert a small sleep at the start of a thread in order
53 to let other runnable threads be scheduled.
54
Tim Petersb07352e2001-09-08 01:25:47 +000055Library
56
Barry Warsaw58b072d2001-09-22 04:44:21 +000057- StringIO.StringIO instances and cStringIO.StringIO instances support
58 iteration just like file objects (i.e. their .readline() method is
59 called for each iteration until it returns an empty string).
60
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +000061- The codecs module has grown four new helper APIs to access
62 builtin codecs: getencoder(), getdecoder(), getreader(),
63 getwriter().
64
Guido van Rossum624c8af2001-09-18 15:21:04 +000065- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
66 simplifies writing XML RPC servers.
67
68- os.path.realpath(): a new function that returns the absoute pathname
69 after interpretation of symbolic links. On non-Unix systems, this
70 is an alias for os.path.abspath().
71
Tim Peters16a77ad2001-09-08 04:00:12 +000072- operator.indexOf() (PySequence_Index() in the C API) now works with any
73 iterable object.
74
Guido van Rossum624c8af2001-09-18 15:21:04 +000075- smtplib now supports various authentication and security features of
76 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +000077
Guido van Rossum624c8af2001-09-18 15:21:04 +000078- hmac: a new module implementing keyed hashing for message
79 authentication.
80
81- mimetypes now recognizes more extensions and file types. At the
82 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +000083
Guido van Rossum624c8af2001-09-18 15:21:04 +000084- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +000085 Python 2.2 bytecode generation. It has also been promoted from a
86 Tool to a standard library package. (Tools/compiler still exists as
87 a sample driver.)
88
89- pydoc and inspect are now aware of new-style classes;
90 e.g. help(list) at the interactive prompt now shows proper
91 documentation for all operations on list objects.
92
93Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +000094
Tim Petersb07352e2001-09-08 01:25:47 +000095Build
96
Guido van Rossum624c8af2001-09-18 15:21:04 +000097- Large file support (LFS) is now automatic when the platform supports
98 it; no more manual configuration tweaks are needed. On Linux, at
99 least, it's possible to have a system whose C library supports large
100 files but whose kernel doesn't; in this case, large file support is
101 still enabled but doesn't do you any good unless you upgrade your
102 kernel or share your Python executable with another system whose
103 kernel has large file support.
104
105- The configure script now supplies plausible defaults in a
106 cross-compilation environment. This doesn't mean that the supplied
107 values are always correct, or that cross-compilation now works
108 flawlessly -- but it's a first step (and it shuts up most of
109 autoconf's warnings about AC_TRY_RUN).
110
111- The Unix build is now a bit less chatty, courtesy of the parser
112 generator. The build is completely silent (except for errors) when
113 using "make -s", thanks to a -q option to setup.py.
114
Tim Petersb07352e2001-09-08 01:25:47 +0000115C API
116
Guido van Rossum624c8af2001-09-18 15:21:04 +0000117- The "structmember" API now supports some new flag bits to deny read
118 and/or write access to attributes in restricted execution mode.
119
Tim Petersb07352e2001-09-08 01:25:47 +0000120New platforms
121
Guido van Rossum624c8af2001-09-18 15:21:04 +0000122- Compaq's iPAQ handheld, running the "familiar" Linux distribution
123 (http://familiar.handhelds.org).
124
Tim Petersb07352e2001-09-08 01:25:47 +0000125Tests
126
127Windows
128
Guido van Rossum624c8af2001-09-18 15:21:04 +0000129- Large file support now also works for files > 4GB, on filesystems
130 that support it (NTFS under Windows 2000).
131
Tim Petersb07352e2001-09-08 01:25:47 +0000132
Tim Petersedc99312001-08-22 21:36:50 +0000133What's New in Python 2.2a3?
134===========================
135
136Core
137
Tim Peters9fffa3e2001-09-04 05:14:19 +0000138- Conversion of long to float now raises OverflowError if the long is too
139 big to represent as a C double.
140
Tim Peters32f453e2001-09-03 08:35:41 +0000141- The 3-argument builtin pow() no longer allows a third non-None argument
142 if either of the first two arguments is a float, or if both are of
143 integer types and the second argument is negative (in which latter case
144 the arguments are converted to float, so this is really the same
145 restriction).
146
Tim Peters5d2b77c2001-09-03 05:47:38 +0000147- The builtin dir() now returns more information, and sometimes much
148 more, generally naming all attributes of an object, and all attributes
149 reachable from the object via its class, and from its class's base
150 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
151 an empty list. In 2.2a3,
152
153 >>> dir([])
154 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
155 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
156 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
157 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
158 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
159 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
160 'reverse', 'sort']
161
162 dir(module) continues to return only the module's attributes, though.
163
Tim Petersbdee63f2001-09-02 03:40:59 +0000164- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000165 than raising OverflowError. This is a partial implementation of PEP
166 237. You can use -Wdefault::OverflowWarning to enable a warning for
167 this situation, and -Werror::OverflowWarning to revert to the old
168 OverflowError exception.
169
Guido van Rossum61c345f2001-09-04 03:26:15 +0000170- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000171 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000172 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
173 -Qold, meaning the / operator has its classic meaning and no
174 warnings are issued. Using -Qwarn issues a run-time warning about
175 all uses of classic division for int and long arguments; -Qwarnall
176 also warns about classic division for float and complex arguments
177 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
178 new division by default, but only in the __main__ module. You can
179 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
180 __main__ module new division, and warns about classic division
181 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000182
Tim Petersbdee63f2001-09-02 03:40:59 +0000183- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000184 long, float, str, unicode, and tuple. (The types complex, list and
185 dictionary can also be subclassed; this was introduced earlier.)
186 Note that restrictions apply when subclassing immutable built-in
187 types: you can only affect the value of the instance by overloading
188 __new__. You can add mutable attributes, and the subclass instances
189 will have a __dict__ attribute, but you cannot change the "value"
190 (as implemented by the base class) of an immutable subclass instance
191 once it is created.
192
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000193- The dictionary constructor now takes an optional argument, a
194 mapping-like object, and initializes the dictionary from its
195 (key, value) pairs.
196
Tim Petersbdee63f2001-09-02 03:40:59 +0000197- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000198 "cooperative super calls" in a multiple inheritance setting. For an
199 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
200
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000201- A new built-in type, property, has been added. This enables the
202 creation of "properties". These are attributes implemented by
203 getter and setter functions (or only one of these for read-only or
204 write-only attributes), without the need to override __getattr__.
205 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000206
Tim Petersbdee63f2001-09-02 03:40:59 +0000207- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000208 liberalized, to allow leading zeroes. Examples of literals now
209 legal that were SyntaxErrors before:
210
211 00.0 0e3 0100j 07.5 00000000000000000008.
212
Tim Petersbdee63f2001-09-02 03:40:59 +0000213- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000214 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
215
Tim Petersedc99312001-08-22 21:36:50 +0000216Library
217
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000218- telnetlib includes symbolic names for the options, and support for
219 setting an option negotiation callback.
220
Tim Petersa40c7932001-09-05 22:36:56 +0000221- The new C standard no longer requires that math libraries set errno to
222 ERANGE on overflow. For platform libraries that exploit this new
223 freedom, Python's overflow-checking was wholly broken. A new overflow-
224 checking scheme attempts to repair that, but may not be reliable on all
225 platforms (C doesn't seem to provide anything both useful and portable
226 in this area anymore).
227
Martin v. Löwis44f86962001-09-05 13:44:54 +0000228- Asynchronous timeout actions are available through the new class
229 threading.Timer.
230
Tim Peters78526162001-09-05 00:53:45 +0000231- math.log and math.log10 now return sensible results for even huge
232 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
233
Tim Petersbdee63f2001-09-02 03:40:59 +0000234- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000235 currently held. See the docs for the imp module.
236
Tim Petersbdee63f2001-09-02 03:40:59 +0000237- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000238 dumps containing ints written on platforms where Python ints are 8 bytes.
239 When read on a box where Python ints are 4 bytes, such values are
240 converted to Python longs.
241
Tim Petersbdee63f2001-09-02 03:40:59 +0000242- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000243 code objects is no longer allowed. This plugs a security hole.
244
Steve Purcell6091cd62001-09-06 16:05:17 +0000245- unittest.TestResult instances no longer store references to tracebacks
246 generated by test failures. This prevents unexpected dangling references
247 to objects that should be garbage collected between tests.
248
Tim Petersedc99312001-08-22 21:36:50 +0000249Tools
250
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000251- Tools/scripts/fixdiv.py has been added which can be used to fix
252 division operators as per PEP 238.
253
Tim Petersedc99312001-08-22 21:36:50 +0000254Build
255
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000256- If you are an adventurous person using Mac OS X you may want to look at
257 Mac/OSX. There is a Makefile there that will build Python as a real Mac
258 application, which can be used for experimenting with Carbon or Cocoa.
259 Discussion of this on pythonmac-sig, please.
260
Tim Peters7eea37e2001-09-04 22:08:56 +0000261C API
262
263- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000264
Tim Peters9fffa3e2001-09-04 05:14:19 +0000265- Note that PyLong_AsDouble can fail! This has always been true, but no
266 callers checked for it. It's more likely to fail now, because overflow
267 errors are properly detected now. The proper way to check:
268
269 double x = PyLong_AsDouble(some_long_object);
270 if (x == -1.0 && PyErr_Occurred()) {
271 /* The conversion failed. */
272 }
273
Tim Petersbdee63f2001-09-02 03:40:59 +0000274- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000275 compile but will not participate in GC. To upgrade an extension
276 module:
277
278 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000279
Neil Schemenauer4042c692001-08-30 15:38:01 +0000280 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
281 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000282
Neil Schemenauer4042c692001-08-30 15:38:01 +0000283 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
284 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000285
Neil Schemenauer4042c692001-08-30 15:38:01 +0000286 - remove PyGC_HEAD_SIZE from object size calculations
287
288 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
289
Tim Petersbdee63f2001-09-02 03:40:59 +0000290- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000291 These can be used safely to construct string objects from a
292 sprintf-style format string (similar to the format string supported
293 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000294
Tim Petersedc99312001-08-22 21:36:50 +0000295New platforms
296
Tim Petersb7da0902001-09-02 23:01:43 +0000297- Stephen Hansen contributed patches sufficient to get a clean compile
298 under Borland C (Windows), but he reports problems running it and ran
299 out of time to complete the port. Volunteers? Expect a MemoryError
300 when importing the types module; this is probably shallow, and
301 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000302
Tim Petersedc99312001-08-22 21:36:50 +0000303Tests
304
305Windows
306
Tim Peters6e13a562001-09-06 00:32:15 +0000307- Large file support is now enabled on Win32 platforms as well as on
308 Win64. This means that, for example, you can use f.tell() and f.seek()
309 to manipulate files larger than 2 gigabytes (provided you have enough
310 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000311 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
312 filesize limit, and large file support makes no difference there.
313 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
314 NTFS has no practical limit on file size, and files of any size can be
315 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000316
Tim Petersbdee63f2001-09-02 03:40:59 +0000317- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000318 points to command.com (patch from Brian Quinlan).
319
Tim Petersedc99312001-08-22 21:36:50 +0000320
Tim Peters20f51a72001-07-21 02:31:40 +0000321What's New in Python 2.2a2?
322===========================
323
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000324Build
325
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000326- Tim Peters developed a brand new Windows installer using Wise 8.1,
327 generously donated to us by Wise Solutions.
328
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000329- configure supports a new option --enable-unicode, with the values
330 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
331 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000332
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000333- A new configure option --enable-framework builds a Mac OS X framework,
334 which "make frameworkinstall" will install. This provides a starting
335 point for more mac-like functionality, join pythonmac-sig@python.org
336 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000337
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000338- The NeXT platform is no longer supported.
339
340- The `new' module is now statically linked.
341
Tim Peters0afb6092001-08-15 06:06:44 +0000342Tools
343
344- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000345 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000346 the module docstring for details.
347
Tim Peters20f51a72001-07-21 02:31:40 +0000348Tests
349
Tim Peters5e824c32001-08-12 22:25:01 +0000350- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000351 platforms, allowing to give clearer test result output. regrtest
352 also has optional --use/-u switch to run normally disabled tests
353 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000354
Tim Peters20f51a72001-07-21 02:31:40 +0000355- Several new tests in the standard test suite, with special thanks to
356 Nick Mathewson.
357
358Core
359
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000360- The floor division operator // has been added as outlined in PEP
361 238. The / operator still provides classic division (and will until
362 Python 3.0) unless "from __future__ import division" is included, in
363 which case the / operator will provide true division. The operator
364 module provides truediv() and floordiv() functions. Augmented
365 assignment variants are included, as are the equivalent overloadable
366 methods and C API methods. See the PEP for a full discussion:
367 <http://python.sf.net/peps/pep-0238.html>
368
Tim Peters6cd6a822001-08-17 22:11:27 +0000369- Future statements are now effective in simulated interactive shells
370 (like IDLE). This should "just work" by magic, but read Michael
371 Hudson's "Future statements in simulated shells" PEP 264 for full
372 details: <http://python.sf.net/peps/pep-0264.html>.
373
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000374- The type/class unification (PEP 252-253) was integrated into the
375 trunk and is not so tentative any more (the exact specification of
376 some features is still tentative). A lot of work has done on fixing
377 bugs and adding robustness and features (performance still has to
378 come a long way).
379
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000380- Warnings about a mismatch in the Python API during extension import
381 now use the Python warning framework (which makes it possible to
382 write filters for these warnings).
383
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000384- A function's __dict__ (aka func_dict) will now always be a
385 dictionary. It used to be possible to delete it or set it to None,
386 but now both actions raise TypeErrors. It is still legal to set it
387 to a dictionary object. Getting func.__dict__ before any attributes
388 have been assigned now returns an empty dictionary instead of None.
389
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000390- A new command line option, -E, was added which disables the use of
391 all environment variables, or at least those that are specifically
392 significant to Python. Usually those have a name starting with
393 "PYTHON". This was used to fix a problem where the tests fail if
394 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
395 older distribution.
396
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000397Library
398
Tim Peters5e824c32001-08-12 22:25:01 +0000399- New class Differ and new functions ndiff() and restore() in difflib.py.
400 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000401 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000402
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000403- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
404 value using the minimal quoting required for the value; more
405 reliable than using xml.sax.saxutils.escape() for attribute values.
406
407- Readline completion support for cmd.Cmd was added.
408
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000409- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
410
411- Added function threading.BoundedSemaphore()
412
413- Added Ka-Ping Yee's cgitb.py module.
414
415- The `new' module now exposes the CO_xxx flags.
416
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000417New platforms
418
419C API
420
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000421- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
422 which provide a cross-platform implementations for the
423 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
424 the standard sprintf() and vsprintf() C lib APIs, these versions
425 apply bounds checking on the used buffer which enhances protection
426 against buffer overruns.
427
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000428- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000429 and extensions using different Unicode widths is rendered next to
430 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000431 will result in an ImportError. Unicode extensions writers must make
432 sure to check the Unicode width compatibility in their extensions by
433 using at least one of the mangled Unicode APIs in the extension.
434
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000435- Two new flags METH_NOARGS and METH_O are available in method definition
436 tables to simplify implementation of methods with no arguments and a
437 single untyped argument. Calling such methods is more efficient than
438 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
439 deprecated.
440
Tim Petersc1731372001-08-04 08:12:36 +0000441Windows
442
443- "import module" now compiles module.pyw if it exists and nothing else
444 relevant is found.
445
Tim Peters20f51a72001-07-21 02:31:40 +0000446
Guido van Rossum55a78992001-07-17 17:22:32 +0000447What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +0000448===========================
449
450Core
Tim Petersa814db52001-05-14 07:05:58 +0000451
Tim Peters6d6c1a32001-08-02 04:15:00 +0000452- TENTATIVELY, a large amount of code implementing much of what's
453 described in PEP 252 (Making Types Look More Like Classes) and PEP
454 253 (Subtyping Built-in Types) was added. This will be released
455 with Python 2.2a1. Documentation will be provided separately
456 through http://www.python.org/2.2/. The purpose of releasing this
457 with Python 2.2a1 is to test backwards compatibility. It is
458 possible, though not likely, that a decision is made not to release
459 this code as part of 2.2 final, if any serious backwards
460 incompapatibilities are found during alpha testing that cannot be
461 repaired.
462
Guido van Rossum55a78992001-07-17 17:22:32 +0000463- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000464 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000465 more 'yield' statements. See PEP 255. Since this adds a new
466 keyword to the language, this feature must be enabled by including a
467 future statement: "from __future__ import generators" (see PEP 236).
468 Generators will become a standard feature in a future release
469 (probably 2.3). Without this future statement, 'yield' remains an
470 ordinary identifier, but a warning is issued each time it is used.
471 (These warnings currently don't conform to the warnings framework of
472 PEP 230; we intend to fix this in 2.2a2.)
473
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000474- The UTF-16 codec was modified to be more RFC compliant. It will now
475 only remove BOM characters at the start of the string and then
476 only if running in native mode (UTF-16-LE and -BE won't remove a
477 leading BMO character).
478
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000479- Strings now have a new method .decode() to complement the already
480 existing .encode() method. These two methods provide direct access
481 to the corresponding decoders and encoders of the registered codecs.
482
483 To enhance the usability of the .encode() method, the special
484 casing of Unicode object return values was dropped (Unicode objects
485 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000486
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000487 Both methods will now return whatever the codec in charge of the
488 requested encoding returns as object, e.g. Unicode codecs will
489 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
490 will return u"äöü"). This enables codec writer to create codecs
491 for various simple to use conversions.
492
493 New codecs were added to demonstrate these new features (the .encode()
494 and .decode() columns indicate the type of the returned objects):
495
496 Name | .encode() | .decode() | Description
497 ----------------------------------------------------------------------
498 uu | string | string | UU codec (e.g. for email)
499 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000500 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000501 zlib | string | string | zlib compression
502 hex | string | string | 2-byte hex codec
503 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
504
Mark Hammond2a0af792001-05-14 03:09:36 +0000505- Some operating systems now support the concept of a default Unicode
506 encoding for file system operations. Notably, Windows supports 'mbcs'
507 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000508 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000509 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000510
511 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000512 functions that return filenames (such as os.listdir()) to return Python
513 string objects pre-encoded using the default file system encoding for
514 the platform. As this encoding is likely to be different from Python's
515 default encoding, converting this name to a Unicode object before passing
516 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000517 would attempt to use its default encoding (generally ASCII) rather than
518 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000519
Tim Petersa814db52001-05-14 07:05:58 +0000520 In general, this change simply removes surprises when working with
521 Unicode and the file system, making these operations work as you expect,
522 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000523 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000524
Tim Peters61dff2b2001-05-08 15:43:37 +0000525- Float (and complex) literals in source code were evaluated to full
526 precision only when running from a .py file; the same code loaded from a
527 .pyc (or .pyo) file could suffer numeric differences starting at about the
528 12th significant decimal digit. For example, on a machine with IEEE-754
529 floating arithmetic,
530
531 x = 9007199254740992.0
532 print long(x)
533
534 printed 9007199254740992 if run directly from .py, but 9007199254740000
535 if from a compiled (.pyc or .pyo) file. This was due to marshal using
536 str(float) instead of repr(float) when building code objects. marshal
537 now uses repr(float) instead, which should reproduce floats to full
538 machine precision (assuming the platform C float<->string I/O conversion
539 functions are of good quality).
540
541 This may cause floating-point results to change in some cases, and
542 usually for the better, but may also cause numerically unstable
543 algorithms to break.
544
Tim Peters2f228e72001-05-13 00:19:31 +0000545- The implementation of dicts suffers fewer collisions, which has speed
546 benefits. However, the order in which dict entries appear in dict.keys(),
547 dict.values() and dict.items() may differ from previous releases for a
548 given dict. Nothing is defined about this order, so no program should
549 rely on it. Nevertheless, it's easy to write test cases that rely on the
550 order by accident, typically because of printing the str() or repr() of a
551 dict to an "expected results" file. See Lib/test/test_support.py's new
552 sortdict(dict) function for a simple way to display a dict in sorted
553 order.
554
Tim Peters7a3bfc32001-06-12 01:22:22 +0000555- Many other small changes to dicts were made, resulting in faster
556 operation along the most common code paths.
557
Guido van Rossum10315822001-05-01 20:54:30 +0000558- Dictionary objects now support the "in" operator: "x in dict" means
559 the same as dict.has_key(x).
560
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000561- The update() method of dictionaries now accepts generic mapping
562 objects. Specifically the argument object must support the .keys()
563 and __getitem__() methods. This allows you to say, for example,
564 {}.update(UserDict())
565
Guido van Rossum10315822001-05-01 20:54:30 +0000566- Iterators were added; this is a generalized way of providing values
567 to a for loop. See PEP 234. There's a new built-in function iter()
568 to return an iterator. There's a new protocol to get the next value
569 from an iterator using the next() method (in Python) or the
570 tp_iternext slot (in C). There's a new protocol to get iterators
571 using the __iter__() method (in Python) or the tp_iter slot (in C).
572 Iterating (i.e. a for loop) over a dictionary generates its keys.
573 Iterating over a file generates its lines.
574
Tim Petersf553f892001-05-01 20:45:31 +0000575- The following functions were generalized to work nicely with iterator
576 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000577 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000578 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
579 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000580 join() method of strings
581 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000582 'x in y' and 'x not in y' (PySequence_Contains() in C API)
583 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000584 right-hand side of assignment statements with multiple targets, such as
585 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000586
Tim Petersd85e1022001-05-11 21:51:48 +0000587- Accessing module attributes is significantly faster (for example,
588 random.random or os.path or yourPythonModule.yourAttribute).
589
Tim Peterse63415e2001-05-08 04:38:29 +0000590- Comparing dictionary objects via == and != is faster, and now works even
591 if the keys and values don't support comparisons other than ==.
592
Tim Peters95bf9392001-05-10 08:32:44 +0000593- Comparing dictionaries in ways other than == and != is slower: there were
594 insecurities in the dict comparison implementation that could cause Python
595 to crash if the element comparison routines for the dict keys and/or
596 values mutated the dicts. Making the code bulletproof slowed it down.
597
Tim Peterseb28ef22001-06-02 05:27:19 +0000598- Collisions in dicts are resolved via a new approach, which can help
599 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000600 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000601 faster now. Thanks to Christian Tismer for pointing out the cause and
602 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000603
Tim Peters52e155e2001-06-16 05:42:57 +0000604- repr() is much faster for large containers (dict, list, tuple).
605
606
Tim Petersa814db52001-05-14 07:05:58 +0000607Library
608
Fred Drake960fdf92001-07-20 18:38:26 +0000609- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
610 were added to the string module. These a locale-indenpendent
611 constants, unlike letters, lowercase, and uppercase. These are now
612 use in appropriate locations in the standard library.
613
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000614- The flags used in dlopen calls can now be configured using
615 sys.setdlopenflags and queried using sys.getdlopenflags.
616
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000617- Fredrik Lundh's xmlrpclib is now a standard library module. This
618 provides full client-side XML-RPC support. In addition,
619 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
620 one asyncore-based). Thanks to Eric Raymond for the documentation.
621
Guido van Rossum643d3912001-07-05 14:46:25 +0000622- The xrange() object is simplified: it no longer supports slicing,
623 repetition, comparisons, efficient 'in' checking, the tolist()
624 method, or the start, stop and step attributes. See PEP 260.
625
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000626- A new function fnmatch.filter to filter lists of file names was added.
627
Barry Warsawffd674d2001-05-22 16:00:10 +0000628- calendar.py uses month and day names based on the current locale.
629
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000630- strop is now *really* obsolete (this was announced before with 1.6),
631 and issues DeprecationWarning when used (except for the four items
632 that are still imported into string.py).
633
Tim Petersa814db52001-05-14 07:05:58 +0000634- Cookie.py now sorts key+value pairs by key in output strings.
635
636- pprint.isrecursive(object) didn't correctly identify recursive objects.
637 Now it does.
638
Tim Peters95b3f782001-05-14 18:39:41 +0000639- pprint functions now much faster for large containers (tuple, list, dict).
640
Tim Peters7b9542a2001-06-10 23:40:19 +0000641- New 'q' and 'Q' format codes in the struct module, corresponding to C
642 types "long long" and "unsigned long long" (on Windows, __int64). In
643 native mode, these can be used only when the platform C compiler supports
644 these types (when HAVE_LONG_LONG is #define'd by the Python config
645 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000646 In standard mode, 'q' and 'Q' are supported on all platforms, and are
647 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000648
Guido van Rossum83213cc2001-06-12 16:48:52 +0000649- The site module installs a new built-in function 'help' that invokes
650 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
651 it displays a message reminding the user to use 'help()' or
652 'help(object)'.
653
Tim Petersa814db52001-05-14 07:05:58 +0000654Tests
655
656- New test_mutants.py runs dict comparisons where the key and value
657 comparison operators mutute the dicts randomly during comparison. This
658 rapidly causes Python to crash under earlier releases (not for the faint
659 of heart: it can also cause Win9x to freeze or reboot!).
660
661- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000662 pprint.isreadable() return sensible results. Also verifies that simple
663 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000664
Tim Peters4324aa32001-05-28 22:30:08 +0000665C API
666
667- Removed the unused last_is_sticky argument from the internal
668 _PyTuple_Resize(). If this affects you, you were cheating.
669
670
Guido van Rossum55a78992001-07-17 17:22:32 +0000671======================================================================
672
673
Guido van Rossumffe13be2001-04-16 18:46:45 +0000674What's New in Python 2.1 (final)?
675=================================
676
677We only changed a few things since the last release candidate, all in
678Python library code:
679
680- A bug in the locale module was fixed that affected locales which
681 define no grouping for numeric formatting.
682
683- A few bugs in the weakref module's implementations of weak
684 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
685 and the test suite was updated to check for these bugs.
686
687- An old bug in the os.path.walk() function (introduced in Python
688 2.0!) was fixed: a non-existent file would cause an exception
689 instead of being ignored.
690
691- Fixed a few bugs in the new symtable module found by Neil Norwitz's
692 PyChecker.
693
694
Guido van Rossum5b08f132001-04-16 02:05:23 +0000695What's New in Python 2.1c2?
696===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000697
Guido van Rossum5b08f132001-04-16 02:05:23 +0000698A flurry of small changes, and one showstopper fixed in the nick of
699time made it necessary to release another release candidate. The list
700here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000701
Guido van Rossum5b08f132001-04-16 02:05:23 +0000702Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000703
Guido van Rossum5b08f132001-04-16 02:05:23 +0000704- Tim discovered a nasty bug in the dictionary code, caused by
705 PyDict_Next() calling dict_resize(), and the GC code's use of
706 PyDict_Next() violating an assumption in dict_items(). This was
707 fixed with considerable amounts of band-aid, but the net effect is a
708 saner and more robust implementation.
709
710- Made a bunch of symbols static that were accidentally global.
711
712Build and Ports
713
714- The setup.py script didn't check for a new enough version of zlib
715 (1.1.3 is needed). Now it does.
716
717- Changed "make clean" target to also remove shared libraries.
718
719- Added a more general warning about the SGI Irix optimizer to README.
720
721Library
722
723- Fix a bug in urllib.basejoin("http://host", "../file.html") which
724 omitted the slash between host and file.html.
725
726- The mailbox module's _Mailbox class contained a completely broken
727 and undocumented seek() method. Ripped it out.
728
729- Fixed a bunch of typos in various library modules (urllib2, smtpd,
730 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
731
732- Fixed a few last-minute bugs in unittest.
733
734Extensions
735
736- Reverted the patch to the OpenSSL code in socketmodule.c to support
737 RAND_status() and the EGD, and the subsequent patch that tried to
738 fix it for pre-0.9.5 versions; the problem with the patch is that on
739 some systems it issues a warning whenever socket is imported, and
740 that's unacceptable.
741
742Tests
743
744- Fixed the pickle tests to work with "import test.test_pickle".
745
746- Tweaked test_locale.py to actually run the test Windows.
747
748- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
749 not "wb" (which is not a valid mode at all).
750
751- Fix pstats browser crashes. Import readline if it exists to make
752 the user interface nicer.
753
754- Add "import thread" to the top of test modules that import the
755 threading module (test_asynchat and test_threadedtempfile). This
756 prevents test failures caused by a broken threading module resulting
757 from a previously caught failed import.
758
759- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
760 needed on some platforms (e.g. Solaris 8) when the tests are run
761 twice in succession.
762
763- Skip rather than fail test_sunaudiodev if no audio device is found.
764
765
766What's New in Python 2.1c1?
767===========================
768
769This list was significantly updated when 2.1c2 was released; the 2.1c1
770release didn't mention most changes that were actually part of 2.1c1:
771
772Legal
773
774- Copyright was assigned to the Python Software Foundation (PSF) and a
775 PSF license (very similar to the CNRI license) was added.
776
777- The CNRI copyright notice was updated to include 2001.
778
779Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000780
Guido van Rossumc9932722001-04-12 02:31:27 +0000781- After a public outcry, assignment to __debug__ is no longer illegal;
782 instead, a warning is issued. It will become illegal in 2.2.
783
Guido van Rossum5b08f132001-04-16 02:05:23 +0000784- Fixed a core dump with "%#x" % 0, and changed the semantics so that
785 "%#x" now always prepends "0x", even if the value is zero.
786
787- Fixed some nits in the bytecode compiler.
788
789- Fixed core dumps when calling certain kinds of non-functions.
790
791- Fixed various core dumps caused by reference count bugs.
792
793Build and Ports
794
795- Use INSTALL_SCRIPT to install script files.
796
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000797- New port: SCO Unixware 7, by Billy G. Allie.
798
Guido van Rossum5b08f132001-04-16 02:05:23 +0000799- Updated RISCOS port.
800
801- Updated BeOS port and notes.
802
803- Various other porting problems resolved.
804
805Library
806
807- The TERMIOS and SOCKET modules are now truly obsolete and
808 unnecessary. Their symbols are incorporated in the termios and
809 socket modules.
810
811- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
812 better tests for pickling.
813
814- threading: make Condition.wait() robust against KeyboardInterrupt.
815
816- zipfile: add support to zipfile to support opening an archive
817 represented by an open file rather than a file name. Fix bug where
818 the archive was not properly closed. Fixed a bug in this bugfix
819 where flush() was called for a read-only file.
820
821- imputil: added an uninstall() method to the ImportManager.
822
823- Canvas: fixed bugs in lower() and tkraise() methods.
824
825- SocketServer: API change (added overridable close_request() method)
826 so that the TCP server can explicitly close the request.
827
828- pstats: Eric Raymond added a simple interactive statistics browser,
829 invoked when the module is run as a script.
830
831- locale: fixed a problem in format().
832
833- webbrowser: made it work when the BROWSER environment variable has a
834 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
835 KDE 2. Fixed some other nits.
836
837- unittest: changes to allow using a different exception than
838 AssertionError, and added a few more function aliases. Some other
839 small changes.
840
841- urllib, urllib2: fixed redirect problems and a coupleof other nits.
842
843- asynchat: fixed a critical bug in asynchat that slipped through the
844 2.1b2 release. Fixed another rare bug.
845
846- Fix some unqualified except: clauses (always a bad code example).
847
848XML
849
850- pyexpat: new API get_version_string().
851
852- Fixed some minidom bugs.
853
854Extensions
855
856- Fixed a core dump in _weakref. Removed the weakref.mapping()
857 function (it adds nothing to the API).
858
859- Rationalized the use of header files in the readline module, to make
860 it compile (albeit with some warnings) with the very recent readline
861 4.2, without breaking for earlier versions.
862
863- Hopefully fixed a buffering problem in linuxaudiodev.
864
865- Attempted a fix to make the OpenSSL support in the socket module
866 work again with pre-0.9.5 versions of OpenSSL.
867
868Tests
869
870- Added a test case for asynchat and asyncore.
871
872- Removed coupling between tests where one test failing could break
873 another.
874
875Tools
876
877- Ping added an interactive help browser to pydoc, fixed some nits
878 in the rest of the pydoc code, and added some features to his
879 inspect module.
880
881- An updated python-mode.el version 4.1 which integrates Ken
882 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
883 much nicer in XEmacs and Emacs. When stepping through your program
884 with pdb, in either the shell window or the *Python* window, the
885 source file and line will be tracked by an arrow. Very cool!
886
887- IDLE: syntax warnings in interactive mode are changed into errors.
888
889- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +0000890 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +0000891
892- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000893
Barry Warsaw11e89c72001-04-11 20:37:57 +0000894
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000895What's New in Python 2.1 beta 2?
896================================
897
Guido van Rossum053ae352001-03-22 14:17:21 +0000898(Unlisted are many fixed bugs, more documentation, etc.)
899
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000900Core language, builtins, and interpreter
901
Guido van Rossum053ae352001-03-22 14:17:21 +0000902- The nested scopes work (enabled by "from __future__ import
903 nested_scopes") is completed; in particular, the future now extends
904 into code executed through exec, eval() and execfile(), and into the
905 interactive interpreter.
906
907- When calling a base class method (e.g. BaseClass.__init__(self)),
908 this is now allowed even if self is not strictly spoken a class
909 instance (e.g. when using metaclasses or the Don Beaudry hook).
910
911- Slice objects are now comparable but not hashable; this prevents
912 dict[:] from being accepted but meaningless.
913
914- Complex division is now calculated using less braindead algorithms.
915 This doesn't change semantics except it's more likely to give useful
916 results in extreme cases. Complex repr() now uses full precision
917 like float repr().
918
919- sgmllib.py now calls handle_decl() for simple <!...> declarations.
920
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000921- It is illegal to assign to the name __debug__, which is set when the
922 interpreter starts. It is effectively a compile-time constant.
923
924- A warning will be issued if a global statement for a variable
925 follows a use or assignment of that variable.
926
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000927Standard library
928
Guido van Rossum053ae352001-03-22 14:17:21 +0000929- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
930 inspired by JUnit), is now part of the standard library. You now
931 have a choice of two testing frameworks: unittest requires you to
932 write testcases as separate code, doctest gathers them from
933 docstrings. Both approaches have their advantages and
934 disadvantages.
935
936- A new module Tix was added, which wraps the Tix extension library
937 for Tk. With that module, it is not necessary to statically link
938 Tix with _tkinter, since Tix will be loaded with Tcl's "package
939 require" command. See Demo/tix/.
940
941- tzparse.py is now obsolete.
942
943- In gzip.py, the seek() and tell() methods are removed -- they were
944 non-functional anyway, and it's better if callers can test for their
945 existence with hasattr().
946
947Python/C API
948
949- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
950 that's already in the dictionary during a PyDict_Next() iteration.
951 This used to fail occasionally when a dictionary resize operation
952 could be triggered that would rehash all the keys. All other
953 modifications to the dictionary are still off-limits during a
954 PyDict_Next() iteration!
955
956- New extended APIs related to passing compiler variables around.
957
958- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
959 implement isinstance() and issubclass().
960
961- Py_BuildValue() now has a "D" conversion to create a Python complex
962 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000963
Fred Drake4e262a92001-03-22 18:26:47 +0000964- Extensions types which support weak references must now set the
965 field allocated for the weak reference machinery to NULL themselves;
966 this is done to avoid the cost of checking each object for having a
967 weakly referencable type in PyObject_INIT(), since most types are
968 not weakly referencable.
969
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000970- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
971 free variables and cell variables to and from the frame's f_locals.
972
973- Variants of several functions defined in pythonrun.h have been added
974 to support the nested_scopes future statement. The variants all end
975 in Flags and take an extra argument, a PyCompilerFlags *; examples:
976 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
977 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +0000978 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000979
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000980Distutils
981
982- the sdist command now writes a PKG-INFO file, as described in PEP 241,
983 into the release tree.
984
Tim Peters0e57abf2001-05-02 07:39:38 +0000985- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000986 (an uninstaller, more customization of the installer's display)
987
988- from Jack Jansen: added Mac-specific code to generate a dialog for
989 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +0000990 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000991 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +0000992
993- added 'platforms' and 'keywords' to the set of metadata that can be
994 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000995
996- applied patches from Jason Tishler to make the compiler class work with
997 Cygwin.
998
999
Tim Peters2fe289a2001-03-01 22:19:38 +00001000What's New in Python 2.1 beta 1?
1001================================
Tim Petersd66595f2001-02-04 03:09:53 +00001002
1003Core language, builtins, and interpreter
1004
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001005- Following an outcry from the community about the amount of code
1006 broken by the nested scopes feature introduced in 2.1a2, we decided
1007 to make this feature optional, and to wait until Python 2.2 (or at
1008 least 6 months) to make it standard. The option can be enabled on a
1009 per-module basis by adding "from __future__ import nested_scopes" at
1010 the beginning of a module (before any other statements, but after
1011 comments and an optional docstring). See PEP 236 (Back to the
1012 __future__) for a description of the __future__ statement. PEP 227
1013 (Statically Nested Scopes) has been updated to reflect this change,
1014 and to clarify the semantics in a number of endcases.
1015
1016- The nested scopes code, when enabled, has been hardened, and most
1017 bugs and memory leaks in it have been fixed.
1018
1019- Compile-time warnings are now generated for a number of conditions
1020 that will break or change in meaning when nested scopes are enabled:
1021
1022 - Using "from...import *" or "exec" without in-clause in a function
1023 scope that also defines a lambda or nested function with one or
1024 more free (non-local) variables. The presence of the import* or
1025 bare exec makes it impossible for the compiler to determine the
1026 exact set of local variables in the outer scope, which makes it
1027 impossible to determine the bindings for free variables in the
1028 inner scope. To avoid the warning about import *, change it into
1029 an import of explicitly name object, or move the import* statement
1030 to the global scope; to avoid the warning about bare exec, use
1031 exec...in... (a good idea anyway -- there's a possibility that
1032 bare exec will be deprecated in the future).
1033
1034 - Use of a global variable in a nested scope with the same name as a
1035 local variable in a surrounding scope. This will change in
1036 meaning with nested scopes: the name in the inner scope will
1037 reference the variable in the outer scope rather than the global
1038 of the same name. To avoid the warning, either rename the outer
1039 variable, or use a global statement in the inner function.
1040
Neil Schemenauera35c6882001-02-27 04:45:05 +00001041- An optional object allocator has been included. This allocator is
1042 optimized for Python objects and should be faster and use less memory
1043 than the standard system allocator. It is not enabled by default
1044 because of possible thread safety problems. The allocator is only
1045 protected by the Python interpreter lock and it is possible that some
1046 extension modules require a thread safe allocator. The object
1047 allocator can be enabled by providing the "--with-pymalloc" option to
1048 configure.
1049
Tim Petersd66595f2001-02-04 03:09:53 +00001050Standard library
1051
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001052- pyexpat now detects the expat version if expat.h defines it. A
1053 number of additional handlers are provided, which are only available
1054 since expat 1.95. In addition, the methods SetParamEntityParsing and
1055 GetInputContext of Parser objects are available with 1.95.x
1056 only. Parser objects now provide the ordered_attributes and
1057 specified_attributes attributes. A new module expat.model was added,
1058 which offers a number of additional constants if 1.95.x is used.
1059
1060- xml.dom offers the new functions registerDOMImplementation and
1061 getDOMImplementation.
1062
1063- xml.dom.minidom offers a toprettyxml method. A number of DOM
1064 conformance issues have been resolved. In particular, Element now
1065 has an hasAttributes method, and the handling of namespaces was
1066 improved.
1067
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001068- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1069 getting information about live Python code, and pydoc.py, a module
1070 for interactively converting docstrings to HTML or text.
1071 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001072 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001073 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1074 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001075
Tim Peters1eff7962001-03-01 02:31:33 +00001076- New library module difflib.py, primarily packaging the SequenceMatcher
1077 class at the heart of the popular ndiff.py file-comparison tool.
1078
1079- doctest.py (a framework for verifying Python code examples in docstrings)
1080 is now part of the std library.
1081
Tim Petersd66595f2001-02-04 03:09:53 +00001082Windows changes
1083
Guido van Rossume3955a82001-03-02 14:05:59 +00001084- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1085 small GUI that lets you browse the module docstrings using your
1086 default web browser.
1087
Tim Peters1eff7962001-03-01 02:31:33 +00001088- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1089 Platforms) is implemented. See
1090
1091 http://python.sourceforge.net/peps/pep-0235.html
1092
1093 for full details, especially the "Current Lower-Left Semantics" section.
1094 The new Windows import rules are simpler than before:
1095
1096 A. If the PYTHONCASEOK environment variable exists, same as
1097 before: silently accept the first case-insensitive match of any
1098 kind; raise ImportError if none found.
1099
1100 B. Else search sys.path for the first case-sensitive match; raise
1101 ImportError if none found.
1102
1103 The same rules have been implented on other platforms with case-
1104 insensitive but case-preserving filesystems too (including Cygwin, and
1105 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001106
Tim Peters25a9ce32001-02-19 07:06:36 +00001107- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1108 what it's supposed to do (and does do under NT and 2000) via direct
1109 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001110 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001111 all Win9x systems before.
1112
Tim Peters1eff7962001-03-01 02:31:33 +00001113- Build: Subproject _test (effectively) renamed to _testcapi.
1114
Tim Peters2fe289a2001-03-01 22:19:38 +00001115New platforms
1116
1117- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1118 Thanks to Steven Majewski!
1119
1120- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1121 Tishler!
1122
Guido van Rossum9089b272001-03-02 06:49:50 +00001123- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1124 Schwertberger! See RISCOS/README for more information -- it seems
1125 that because of the bizarre filename conventions on RISCOS, no port
1126 to that platform is easy. Note that the new variable os.endsep is
1127 silently supported in order to make life easier on this platform,
1128 but we don't advertise it because it's not worth for most folks to
1129 care about RISCOS portability.
1130
Tim Peters25a9ce32001-02-19 07:06:36 +00001131
Tim Petersd7b5e882001-01-25 03:36:26 +00001132What's New in Python 2.1 alpha 2?
1133=================================
Tim Peters40ead762001-01-27 05:35:26 +00001134
Tim Petersd7b5e882001-01-25 03:36:26 +00001135Core language, builtins, and interpreter
1136
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001137- Scopes nest. If a name is used in a function or class, but is not
1138 local, the definition in the nearest enclosing function scope will
1139 be used. One consequence of this change is that lambda statements
1140 could reference variables in the namespaces where the lambda is
1141 defined. In some unusual cases, this change will break code.
1142
1143 In all previous version of Python, names were resolved in exactly
1144 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001145 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001146 function A is defined within a function B, the names bound in B are
1147 not visible in A. The new rules make names bound in B visible in A,
1148 unless A contains a name binding that hides the binding in B.
1149
1150 Section 4.1 of the reference manual describes the new scoping rules
1151 in detail. The test script in Lib/test/test_scope.py demonstrates
1152 some of the effects of the change.
1153
1154 The new rules will cause existing code to break if it defines nested
1155 functions where an outer function has local variables with the same
1156 name as globals or builtins used by the inner function. Example:
1157
1158 def munge(str):
1159 def helper(x):
1160 return str(x)
1161 if type(str) != type(''):
1162 str = helper(str)
1163 return str.strip()
1164
1165 Under the old rules, the name str in helper() is bound to the
1166 builtin function str(). Under the new rules, it will be bound to
1167 the argument named str and an error will occur when helper() is
1168 called.
1169
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001170- The compiler will report a SyntaxError if "from ... import *" occurs
1171 in a function or class scope. The language reference has documented
1172 that this case is illegal, but the compiler never checked for it.
1173 The recent introduction of nested scope makes the meaning of this
1174 form of name binding ambiguous. In a future release, the compiler
1175 may allow this form when there is no possibility of ambiguity.
1176
Tim Peters40ead762001-01-27 05:35:26 +00001177- repr(string) is easier to read, now using hex escapes instead of octal,
1178 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1179
1180 >>> "\texample \r\n" + chr(0) + chr(255)
1181 '\texample \r\n\x00\xff' # in 2.1
1182 '\011example \015\012\000\377' # in 2.0
1183
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001184- Functions are now compared and hashed by identity, not by value, since
1185 the func_code attribute is writable.
1186
Fred Drakefb9d7122001-02-01 20:00:40 +00001187- Weak references (PEP 205) have been added. This involves a few
1188 changes in the core, an extension module (_weakref), and a Python
1189 module (weakref). The weakref module is the public interface. It
1190 includes support for "explicit" weak references, proxy objects, and
1191 mappings with weakly held values.
1192
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001193- A 'continue' statement can now appear in a try block within the body
1194 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001195 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001196
Tim Petersd7b5e882001-01-25 03:36:26 +00001197Standard library
1198
Barry Warsaw30dbd142001-01-31 22:14:01 +00001199- mailbox.py now has a new class, PortableUnixMailbox which is
1200 identical to UnixMailbox but uses a more portable scheme for
1201 determining From_ separators. Also, the constructors for all the
1202 classes in this module have a new optional `factory' argument, which
1203 is a callable used when new message classes must be instantiated by
1204 the next() method.
1205
Tim Petersd7b5e882001-01-25 03:36:26 +00001206- random.py is now self-contained, and offers all the functionality of
1207 the now-deprecated whrandom.py. See the docs for details. random.py
1208 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001209 and restoring the internal state of the generator; and jumpahead(n),
1210 for quickly forcing the internal state to be the same as if n calls to
1211 random() had been made. The latter is particularly useful for multi-
1212 threaded programs, creating one instance of the random.Random() class for
1213 each thread, then using .jumpahead() to force each instance to use a
1214 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001215
Tim Peters0de88fc2001-02-01 04:59:18 +00001216- random.py's seed() function is new. For bit-for-bit compatibility with
1217 prior releases, use the whseed function instead. The new seed function
1218 addresses two problems: (1) The old function couldn't produce more than
1219 about 2**24 distinct internal states; the new one about 2**45 (the best
1220 that can be done in the Wichmann-Hill generator). (2) The old function
1221 sometimes produced identical internal states when passed distinct
1222 integers, and there was no simple way to predict when that would happen;
1223 the new one guarantees to produce distinct internal states for all
1224 arguments in [0, 27814431486576L).
1225
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001226- The socket module now supports raw packets on Linux. The socket
1227 family is AF_PACKET.
1228
Tim Peters9ea17ac2001-02-02 05:57:15 +00001229- test_capi.py is a start at running tests of the Python C API. The tests
1230 are implemented by the new Modules/_testmodule.c.
1231
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001232- A new extension module, _symtable, provides provisional access to the
1233 internal symbol table used by the Python compiler. A higher-level
1234 interface will be added on top of _symtable in a future release.
1235
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001236- Removed the obsolete soundex module.
1237
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001238- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1239 the isSameNode method; NamedNodeMap the get method.
1240
1241- xml.sax.expatreader supports the lexical handler property; it
1242 generates comment, startCDATA, and endCDATA events.
1243
Tim Petersee826f82001-01-31 19:39:44 +00001244Windows changes
1245
1246- Build procedure: the zlib project is built in a different way that
1247 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001248 the zlib binary used. See PCbuild\readme.txt for details. Your old
1249 zlib-related directories can be deleted; you'll need to download fresh
1250 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001251
Tim Peters9ea17ac2001-02-02 05:57:15 +00001252- Build: New subproject _test for the benefit of test_capi.py (see above).
1253
Tim Petersb16c56f2001-02-02 21:24:51 +00001254- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1255 interface to some Python compiler internals).
1256
1257- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001258 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001259
Tim Petersa3a3a032000-11-30 05:22:44 +00001260What's New in Python 2.1 alpha 1?
1261=================================
1262
1263Core language, builtins, and interpreter
1264
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001265- There is a new Unicode companion to the PyObject_Str() API
1266 called PyObject_Unicode(). It behaves in the same way as the
1267 former, but assures that the returned value is an Unicode object
1268 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001269
Guido van Rossumf98eda02001-01-17 15:54:45 +00001270- The comparison operators support "rich comparison overloading" (PEP
1271 207). C extension types can provide a rich comparison function in
1272 the new tp_richcompare slot in the type object. The cmp() function
1273 and the C function PyObject_Compare() first try the new rich
1274 comparison operators before trying the old 3-way comparison. There
1275 is also a new C API PyObject_RichCompare() (which also falls back on
1276 the old 3-way comparison, but does not constrain the outcome of the
1277 rich comparison to a Boolean result).
1278
1279 The rich comparison function takes two objects (at least one of
1280 which is guaranteed to have the type that provided the function) and
1281 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1282 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1283 object, which may be NotImplemented (in which case the tp_compare
1284 slot function is used as a fallback, if defined).
1285
1286 Classes can overload individual comparison operators by defining one
1287 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001288 __ge__. There are no explicit "reflected argument" versions of
1289 these; instead, __lt__ and __gt__ are each other's reflection,
1290 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1291 reflection (similar at the C level). No other implications are
1292 made; in particular, Python does not assume that == is the Boolean
1293 inverse of !=, or that < is the Boolean inverse of >=. This makes
1294 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001295
1296 Classes or types that want to implement (in)equality tests but not
1297 the ordering operators (i.e. unordered types) should implement ==
1298 and !=, and raise an error for the ordering operators.
1299
Guido van Rossuma88479f2001-01-18 14:28:08 +00001300 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001301 Boolean; e.g. a matrix type might want to return a matrix of bits
1302 for A < B, giving elementwise comparisons. Such types should ensure
1303 that any interpretation of their value in a Boolean context raises
1304 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1305 at the C level) to always raise an exception.
1306
Guido van Rossuma88479f2001-01-18 14:28:08 +00001307- Complex numbers use rich comparisons to define == and != but raise
1308 an exception for <, <=, > and >=. Unfortunately, this also means
1309 that cmp() of two complex numbers raises an exception when the two
1310 numbers differ. Since it is not mathematically meaningful to compare
1311 complex numbers except for equality, I hope that this doesn't break
1312 too much code.
1313
Tim Peters3389f192001-02-18 08:48:49 +00001314- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001315 not defined by the language, other than that it's arbitrary but
1316 consistent (see the Reference Manual). An implementation detail changed
1317 in 2.1a1 such that None now compares less than any other object. Code
1318 relying on this new behavior (like code that relied on the previous
1319 behavior) does so at its own risk.
1320
Barry Warsaw573b5412001-01-15 20:43:18 +00001321- Functions and methods now support getting and setting arbitrarily
1322 named attributes (PEP 232). Functions have a new __dict__
1323 (a.k.a. func_dict) which hold the function attributes. Methods get
1324 and set attributes on their underlying im_func. It is a TypeError
1325 to set an attribute on a bound method.
1326
Guido van Rossum051e3352001-01-15 19:11:10 +00001327- The xrange() object implementation has been improved so that
1328 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1329 limitation that in this case len(xrange(sys.maxint)) can't be
1330 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1331 work fine as long as the index i doesn't actually reach 2**31.
1332 (Python uses regular ints for sequence and string indices; fixing
1333 that is much more work.)
1334
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001335- Two changes to from...import:
1336
Guido van Rossumba381232001-02-03 15:06:40 +00001337 1) "from M import X" now works even if (after loading module M)
1338 sys.modules['M'] is not a real module; it's basically a getattr()
1339 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001340
1341 2) "from M import *" now looks for M.__all__ to decide which names to
1342 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1343 filters out names starting with '_' as before. Whether or not
1344 __all__ exists, there's no restriction on the type of M.
1345
Guido van Rossumf61f1662001-01-10 20:13:55 +00001346- File objects have a new method, xreadlines(). This is the fastest
1347 way to iterate over all lines in a file:
1348
1349 for line in file.xreadlines():
1350 ...do something to line...
1351
1352 See the xreadlines module (mentioned below) for how to do this for
1353 other file-like objects.
1354
1355- Even if you don't use file.xreadlines(), you may expect a speedup on
1356 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001357 quite a bit in platform-specific ways: on systems (like Linux) that
1358 support flockfile(), getc_unlocked(), and funlockfile(), those are
1359 used by default. On systems (like Windows) without getc_unlocked(),
1360 a complicated (but still thread-safe) method using fgets() is used by
1361 default.
1362
Tim Petersd52269b2001-01-25 06:23:18 +00001363 You can force use of the fgets() method by #define'ing
1364 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001365 getc_unlocked()).
1366
Tim Petersd52269b2001-01-25 06:23:18 +00001367 You can force fgets() not to be used by #define'ing
1368 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001369 test_bufio.py fails -- and let us know if it does!).
1370
1371- In addition, the fileinput module, while still slower than the other
1372 methods on most platforms, has been sped up too, by using
1373 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001374
1375- Support for run-time warnings has been added, including a new
1376 command line option (-W) to specify the disposition of warnings.
1377 See the description of the warnings module below.
1378
1379- Extensive changes have been made to the coercion code. This mostly
1380 affects extension modules (which can now implement mixed-type
1381 numerical operators without having to use coercion), but
1382 occasionally, in boundary cases the coercion semantics have changed
1383 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001384 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001385 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001386 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001387
Guido van Rossumf98eda02001-01-17 15:54:45 +00001388- In connection with the coercion changes, a new built-in singleton
1389 object, NotImplemented is defined. This can be returned for
1390 operations that wish to indicate they are not implemented for a
1391 particular combination of arguments. From C, this is
1392 Py_NotImplemented.
1393
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001394- The interpreter accepts now bytecode files on the command line even
1395 if they do not have a .pyc or .pyo extension. On Linux, after executing
1396
Martin v. Löwise214baa2001-02-04 22:37:56 +00001397import imp,sys,string
1398magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1399reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1400open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001401
1402 any byte code file can be used as an executable (i.e. as an argument
1403 to execve(2)).
1404
Tim Peters9940b802000-12-01 07:59:35 +00001405- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001406 character. In 1.6 and earlier, they never produced a sign,
1407 and raised an error if the value of the long was too large
1408 to fit in a Python int. In 2.0, they produced a sign if and
1409 only if too large to fit in an int. This was inconsistent
1410 across platforms (because the size of an int varies across
1411 platforms), and inconsistent with hex() and oct(). Example:
1412
1413 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001414 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001415 'ffffffbe' # in 2.0 and before, on 32-bit machines
1416 >>> hex(-0x42L)
1417 '-0x42L' # in all versions of Python
1418
Tim Peters9940b802000-12-01 07:59:35 +00001419 The behavior of %d formats for negative Python longs remains
1420 the same as in 2.0 (although in 1.6 and before, they raised
1421 an error if the long didn't fit in a Python int).
1422
1423 %u formats don't make sense for Python longs, but are allowed
1424 and treated the same as %d in 2.1. In 2.0, a negative long
1425 formatted via %u produced a sign if and only if too large to
1426 fit in an int. In 1.6 and earlier, a negative long formatted
1427 via %u raised an error if it was too big to fit in an int.
1428
Guido van Rossum3661d392000-12-12 22:10:31 +00001429- Dictionary objects have an odd new method, popitem(). This removes
1430 an arbitrary item from the dictionary and returns it (in the form of
1431 a (key, value) pair). This can be useful for algorithms that use a
1432 dictionary as a bag of "to do" items and repeatedly need to pick one
1433 item. Such algorithms normally end up running in quadratic time;
1434 using popitem() they can usually be made to run in linear time.
1435
Tim Peters36cdad12000-12-29 02:06:45 +00001436Standard library
1437
Thomas Woutersfe385252001-01-19 23:16:56 +00001438- In the time module, the time argument to the functions strftime,
1439 localtime, gmtime, asctime and ctime is now optional, defaulting to
1440 the current time (in the local timezone).
1441
Guido van Rossumda91f222001-01-15 16:36:08 +00001442- The ftplib module now defaults to passive mode, which is deemed a
1443 more useful default given that clients are often inside firewalls
1444 these days. Note that this could break if ftplib is used to connect
1445 to a *server* that is inside a firewall, from outside; this is
1446 expected to be a very rare situation. To fix that, you can call
1447 ftp.set_pasv(0).
1448
Martin v. Löwis10a27872001-01-13 09:54:41 +00001449- The module site now treats .pth files not only for path configuration,
1450 but also supports extensions to the initialization code: Lines starting
1451 with import are executed.
1452
Guido van Rossumf61f1662001-01-10 20:13:55 +00001453- There's a new module, warnings, which implements a mechanism for
1454 issuing and filtering warnings. There are some new built-in
1455 exceptions that serve as warning categories, and a new command line
1456 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1457 turns warnings into errors). warnings.warn(message[, category])
1458 issues a warning message; this can also be called from C as
1459 PyErr_Warn(category, message).
1460
1461- A new module xreadlines was added. This exports a single factory
1462 function, xreadlines(). The intention is that this code is the
1463 absolutely fastest way to iterate over all lines in an open
1464 file(-like) object:
1465
1466 import xreadlines
1467 for line in xreadlines.xreadlines(file):
1468 ...do something to line...
1469
1470 This is equivalent to the previous the speed record holder using
1471 file.readlines(sizehint). Note that if file is a real file object
1472 (as opposed to a file-like object), this is equivalent:
1473
1474 for line in file.xreadlines():
1475 ...do something to line...
1476
Tim Peters36cdad12000-12-29 02:06:45 +00001477- The bisect module has new functions bisect_left, insort_left,
1478 bisect_right and insort_right. The old names bisect and insort
1479 are now aliases for bisect_right and insort_right. XXX_right
1480 and XXX_left methods differ in what happens when the new element
1481 compares equal to one or more elements already in the list: the
1482 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001483 right. Code that doesn't care where equal elements end up should
1484 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001485
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001486- The new curses.panel module wraps the panel library that forms part
1487 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1488
Guido van Rossumf61f1662001-01-10 20:13:55 +00001489- The SocketServer module now sets the allow_reuse_address flag by
1490 default in the TCPServer class.
1491
1492- A new function, sys._getframe(), returns the stack frame pointer of
1493 the caller. This is intended only as a building block for
1494 higher-level mechanisms such as string interpolation.
1495
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001496- The pyexpat module supports a number of new handlers, which are
1497 available only in expat 1.2. If invocation of a callback fails, it
1498 will report an additional frame in the traceback. Parser objects
1499 participate now in garbage collection. If expat reports an unknown
1500 encoding, pyexpat will try to use a Python codec; that works only
1501 for single-byte charsets. The parser type objects is exposed as
1502 XMLParserObject.
1503
1504- xml.dom now offers standard definitions for symbolic node type and
1505 exception code constants, and a hierarchy of DOM exceptions. minidom
1506 was adjusted to use them.
1507
1508- The conformance of xml.dom.minidom to the DOM specification was
1509 improved. It detects a number of additional error cases; the
1510 previous/next relationship works even when the tree is modified;
1511 Node supports the normalize() method; NamedNodeMap, DocumentType and
1512 DOMImplementation classes were added; Element supports the
1513 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1514 method.
1515
Guido van Rossumf61f1662001-01-10 20:13:55 +00001516Build issues
1517
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001518- For Unix (and Unix-compatible) builds, configuration and building of
1519 extension modules is now greatly automated. Rather than having to
1520 edit the Modules/Setup file to indicate which modules should be
1521 built and where their include files and libraries are, a
1522 distutils-based setup.py script now takes care of building most
1523 extension modules. All extension modules built this way are built
1524 as shared libraries. Only a few modules that must be linked
1525 statically are still listed in the Setup file; you won't need to
1526 edit their configuration.
1527
1528- Python should now build out of the box on Cygwin. If it doesn't,
1529 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001530
1531- Python now always uses its own (renamed) implementation of getopt()
1532 -- there's too much variation among C library getopt()
1533 implementations.
1534
1535- C++ compilers are better supported; the CXX macro is always set to a
1536 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001537
Tim Petersd92dfe02000-12-12 01:18:41 +00001538Windows changes
1539
1540- select module: By default under Windows, a select() call
1541 can specify no more than 64 sockets. Python now boosts
1542 this Microsoft default to 512. If you need even more than
1543 that, see the MS docs (you'll need to #define FD_SETSIZE
1544 and recompile Python from source).
1545
Guido van Rossumf61f1662001-01-10 20:13:55 +00001546- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1547 subdirectory is no more!
1548
Tim Petersa3a3a032000-11-30 05:22:44 +00001549
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001550What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001551=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001552
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001553Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001554changes are in the file HISTORY. If you are making the jump directly
1555from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1556HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001557
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001558Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1559the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1560http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001561
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001562--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001563
1564======================================================================
1565
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001566What's new in 2.0 (since release candidate 1)?
1567==============================================
1568
1569Standard library
1570
1571- The copy_reg module was modified to clarify its intended use: to
1572 register pickle support for extension types, not for classes.
1573 pickle() will raise a TypeError if it is passed a class.
1574
1575- Fixed a bug in gettext's "normalize and expand" code that prevented
1576 it from finding an existing .mo file.
1577
1578- Restored support for HTTP/0.9 servers in httplib.
1579
Tim Peters989b7b92000-10-16 20:24:53 +00001580- The math module was changed to stop raising OverflowError in case of
1581 underflow, and return 0 instead in underflow cases. Whether Python
1582 used to raise OverflowError in case of underflow was platform-
1583 dependent (it did when the platform math library set errno to ERANGE
1584 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001585
1586- Fixed a bug in StringIO that occurred when the file position was not
1587 at the end of the file and write() was called with enough data to
1588 extend past the end of the file.
1589
1590- Fixed a bug that caused Tkinter error messages to get lost on
1591 Windows. The bug was fixed by replacing direct use of
1592 interp->result with Tcl_GetStringResult(interp).
1593
1594- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1595 redirect response.
1596
1597- Several changes were made to distutils: Some debugging code was
1598 removed from util. Fixed the installer used when an external zip
1599 program (like WinZip) is not found; the source code for this
1600 installer is in Misc/distutils. check_lib() was modified to behave
1601 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1602 test for whether installed modules are on sys.path was changed to
1603 use both normcase() and normpath().
1604
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001605- Several minor bugs were fixed in the xml package (the minidom,
1606 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001607
1608- The regression test driver (regrtest.py) behavior when invoked with
1609 -l changed: It now reports a count of objects that are recognized as
1610 garbage but not freed by the garbage collector.
1611
Tim Peters989b7b92000-10-16 20:24:53 +00001612- The regression test for the math module was changed to test
1613 exceptional behavior when the test is run in verbose mode. Python
1614 cannot yet guarantee consistent exception behavior across platforms,
1615 so the exception part of test_math is run only in verbose mode, and
1616 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001617
1618Internals
1619
1620- PyOS_CheckStack() has been disabled on Win64, where it caused
1621 test_sre to fail.
1622
1623Build issues
1624
1625- Changed compiler flags, so that gcc is always invoked with -Wall and
1626 -Wstrict-prototypes. Users compiling Python with GCC should see
1627 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001628 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001629 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001630
Tim Petersa3a3a032000-11-30 05:22:44 +00001631- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001632
1633Tools and other miscellany
1634
1635- The compiler in Tools/compiler was updated to support the new
1636 language features introduced in 2.0: extended print statement, list
1637 comprehensions, and augmented assignments. The new compiler should
1638 also be backwards compatible with Python 1.5.2; the compiler will
1639 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001640 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001641
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001642What's new in 2.0 release candidate 1 (since beta 2)?
1643=====================================================
1644
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001645What is release candidate 1?
1646
1647We believe that release candidate 1 will fix all known bugs that we
1648intend to fix for the 2.0 final release. This release should be a bit
1649more stable than the previous betas. We would like to see even more
1650widespread testing before the final release, so we are producing this
1651release candidate. The final release will be exactly the same unless
1652any show-stopping (or brown bag) bugs are found by testers of the
1653release candidate.
1654
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001655All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001656to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001657
1658Core language, builtins, and interpreter
1659
1660- A bug that caused crashes when __coerce__ was used with augmented
1661 assignment, e.g. +=, was fixed.
1662
1663- Raise ZeroDivisionError when raising zero to a negative number,
1664 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1665 power operator and the result of math.pow(0.0, -2.0) will vary by
1666 platform. On Linux, it raises a ValueError.
1667
1668- A bug in Unicode string interpolation was fixed that occasionally
1669 caused errors with formats including "%%". For example, the
1670 following expression "%% %s" % u"abc" no longer raises a TypeError.
1671
1672- Compilation of deeply nested expressions raises MemoryError instead
1673 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1674
1675- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1676 rendering them useless. They are now written in binary mode again.
1677
1678Standard library
1679
1680- Keyword arguments are now accepted for most pattern and match object
1681 methods in SRE, the standard regular expression engine.
1682
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001683- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001684 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001685
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001686- Several bugs in the Unicode handling and error handling in _tkinter
1687 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001688
1689- Fix memory management errors in Merge() and Tkapp_Call() routines.
1690
1691- Several changes were made to cStringIO to make it compatible with
1692 the file-like object interface and with StringIO. If operations are
1693 performed on a closed object, an exception is raised. The truncate
1694 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001695 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001696
1697- There were many changes made to the linuxaudiodev module and its
1698 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001699 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001700
1701 Note that this module is named poorly, because it should work
1702 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001703 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001704
1705 The module now raises exceptions when errors occur instead of
1706 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1707 audio) and defines a getptr() method that calls the
1708 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1709
1710- The library_version attribute, introduced in an earlier beta, was
1711 removed because it can not be supported with early versions of the C
1712 readline library, which provides no way to determine the version at
1713 compile-time.
1714
1715- The binascii module is now enabled on Win64.
1716
Tim Peters46446d62000-10-09 21:19:31 +00001717- tokenize.py no longer suffers "recursion depth" errors when parsing
1718 programs with very long string literals.
1719
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001720Internals
1721
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001722- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001723 which is called when the interpreter starts up to determine where
1724 the standard library is installed. These vulnerabilities affect all
1725 previous versions of Python and can be exploited by setting very
1726 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1727 setuid Python script, although use of the wrapper in
1728 Misc/setuid-prog.c will eliminate the vulnerability.
1729
1730- Fixed garbage collection bugs in instance creation that were
1731 triggered when errors occurred during initialization. The solution,
1732 applied in cPickle and in PyInstance_New(), is to call
1733 PyObject_GC_Init() after the initialization of the object's
1734 container attributes is complete.
1735
1736- pyexpat adds definitions of PyModule_AddStringConstant and
1737 PyModule_AddObject if the Python version is less than 2.0, which
1738 provides compatibility with PyXML on Python 1.5.2.
1739
1740- If the platform has a bogus definition for LONG_BIT (the number of
1741 bits in a long), an error will be reported at compile time.
1742
1743- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1744 collection crashes and possibly other, unreported crashes.
1745
1746- Fixed a memory leak in _PyUnicode_Fini().
1747
1748Build issues
1749
1750- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001751 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001752 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001753
1754- The mmap.PAGESIZE constant is now initialized using sysconf when
1755 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1756
1757- The md5 file should now compile on all platforms.
1758
1759- The select module now compiles on platforms that do not define
1760 POLLRDNORM and related constants.
1761
1762- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001763 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001764
Jeremy Hylton10921202000-10-09 18:34:12 +00001765- BeOS: A number of changes were made to the build and installation
1766 process. ar-fake now operates on a directory of object files.
1767 dl_export.h is gone, and its macros now appear on the mwcc command
1768 line during build on PPC BeOS.
1769
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001770- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001771 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001772
1773- Cygwin: Support for shared libraries, Tkinter, and sockets.
1774
1775- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1776
1777Tools and other miscellany
1778
1779- Removed debugging prints from main used with freeze.
1780
Tim Peters46446d62000-10-09 21:19:31 +00001781- IDLE auto-indent no longer crashes when it encounters Unicode
1782 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001783
1784What's new in 2.0 beta 2 (since beta 1)?
1785========================================
1786
1787Core language, builtins, and interpreter
1788
Tim Peters482c0212000-09-26 06:33:09 +00001789- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001790 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001791
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001792- Add -h and -V command line options to print the usage message and
1793 Python version number and exit immediately.
1794
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001795- eval() and exec accept Unicode objects as code parameters.
1796
1797- getattr() and setattr() now also accept Unicode objects for the
1798 attribute name, which are converted to strings using the default
1799 encoding before lookup.
1800
1801- Multiplication on string and Unicode now does proper bounds
1802 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1803 string is too long."
1804
1805- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001806 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001807
Jeremy Hylton1b618592000-09-26 05:32:36 +00001808
1809Standard library and extensions
1810
Guido van Rossum5b08f132001-04-16 02:05:23 +00001811- socket module: the OpenSSL code now adds support for RAND_status()
1812 and EGD (Entropy Gathering Device).
1813
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001814- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001815 argument checking; it still takes no arguments.
1816
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001817- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001818
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001819- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001820
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001821- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001822
1823- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001824 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001825
1826- copy: Copy Unicode objects atomically.
1827
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001828- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001829
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001830- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001831
Fred Drake67233bc2000-09-26 16:40:27 +00001832- dbm: Add get() and setdefault() methods to dbm object. Add constant
1833 `library' to module that names the library used. Added doc strings
1834 and method names to error messages. Uses configure to determine
1835 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
1836 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001837
1838- distutils: Update to version 0.9.3.
1839
1840- dl: Add several dl.RTLD_ constants.
1841
1842- fpectl: Now supported on FreeBSD.
1843
1844- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
1845 found by the collector will be saved in gc.garbage. This is useful
1846 for debugging a program that creates reference cycles.
1847
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001848- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00001849 of HTTP class. Do not close socket on zero-length response. Do not
1850 crash when server sends invalid content-length header.
1851
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001852- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001853
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001854- marshal: When reading a short, sign-extend on platforms where shorts
1855 are bigger than 16 bits. When reading a long, repair the unportable
1856 sign extension that was being done for 64-bit machines. (It assumed
1857 that signed right shift sign-extends.)
1858
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001859- operator: Add contains(), invert(), __invert__() as aliases for
1860 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001861
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001862- os: Add support for popen2() and popen3() on all platforms where
1863 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001864
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001865- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00001866 clicking on a file in Explorer (or passing the file name to the
1867 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001868
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001869- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00001870 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001871
1872- pickle: Now raises ValueError when an invalid pickle that contains
1873 a non-string repr where a string repr was expected. This behavior
1874 matches cPickle.
1875
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001876- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001877
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001878- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001879
1880- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001881 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001882 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001883
1884- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001885 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001886
1887- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00001888 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00001889 few cycles during startup since the first call to
1890 setdefaultencoding() will initialize the codec registry and the
1891 encodings package.
1892
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001893- socket: Support for size hint in readlines() method of object returned
1894 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001895
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001896- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001897 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001898 is followed by whitespace.
1899
Tim Petersa3a3a032000-11-30 05:22:44 +00001900- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001901
1902- struct: Check ranges for bytes and shorts.
1903
1904- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001905 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001906
1907- Tkinter: Image objects are now guaranteed to have unique ids. Set
1908 event.delta to zero if Tk version doesn't support mousewheel.
1909 Removed some debugging prints.
1910
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001911- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001912
Fred Drake67233bc2000-09-26 16:40:27 +00001913- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001914 which works around a bug in Norton AntiVirus 2000 that leads directly
1915 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001916
1917- xml: New version detection code allows PyXML to override standard
1918 XML package if PyXML version is greater than 0.6.1.
1919
Fred Drake64bb3802000-09-26 16:21:35 +00001920- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
1921 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
1922 tree only for nodes which are sufficiently interesting to a specific
1923 application. Does not provide the HTML-specific extensions. Still
1924 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001925
Fred Drake64bb3802000-09-26 16:21:35 +00001926- xml.sax: SAX 2 support for Python, including all the handler
1927 interfaces needed to process XML 1.0 compliant XML. Some
1928 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001929
Fred Drake64bb3802000-09-26 16:21:35 +00001930- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
1931 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001932
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001933
Jeremy Hylton1b618592000-09-26 05:32:36 +00001934C API
1935
1936- Add three new convenience functions for module initialization --
1937 PyModule_AddObject(), PyModule_AddIntConstant(), and
1938 PyModule_AddStringConstant().
1939
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001940- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00001941 removed and add #error to Python.h if NULL isn't defined after
1942 #include of stdio.h.
1943
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001944- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00001945 backwards compatibility (at the source level) with old extensions.
1946
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001947- A wrapper API was added for signal() and sigaction(). Instead of
1948 either function, always use PyOS_getsig() to get a signal handler
1949 and PyOS_setsig() to set one. A new convenience typedef
1950 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001951
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001952- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00001953 internal data buffer and size of a string object -- or the default
1954 encoded version of a Unicode object.
1955
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001956- PyString_Size() and PyString_AsString() accept Unicode objects.
1957
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001958- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00001959 exists). INT_MAX and LONG_MAX will always be defined, even if
1960 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001961
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001962- PyFloat_FromString takes a second argument, pend, that was
1963 effectively useless. It is now officially useless but preserved for
1964 backwards compatibility. If the pend argument is not NULL, *pend is
1965 set to NULL.
1966
1967- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
1968 for the attribute name. See note on getattr() above.
1969
1970- A few bug fixes to argument processing for Unicode.
1971 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
1972 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
1973 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00001974 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001975
1976- Py_BuildValue accepts B format (for bgen-generated code).
1977
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001978
Jeremy Hylton1b618592000-09-26 05:32:36 +00001979Internals
1980
1981- On Unix, fix code for finding Python installation directory so that
1982 it works when argv[0] is a relative path.
1983
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00001984- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001985 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00001986 rather than by generating a copy of the object.
1987
Tim Peters482c0212000-09-26 06:33:09 +00001988- Several of the internal Unicode tables are much smaller now, and
1989 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001990
Jeremy Hylton97693b02000-09-26 17:42:51 +00001991- In the garbage collector: Fixed bug in collection of tuples. Fixed
1992 bug that caused some instances to be removed from the container set
1993 while they were still live. Fixed parsing in gc.set_debug() for
1994 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001995
1996- Fixed refcount problem in instance deallocation that only occurred
1997 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
1998
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001999- On Windows, getpythonregpath is now protected against null data in
2000 registry key.
2001
2002- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002003 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002004
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002005
Jeremy Hylton1b618592000-09-26 05:32:36 +00002006Build and platform-specific issues
2007
2008- Better support of GNU Pth via --with-pth configure option.
2009
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002010- Python/C API now properly exposed to dynamically-loaded extension
2011 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002012
2013- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2014 Don't define MS_SYNC to be zero when it is undefined. Added missing
2015 prototypes in posixmodule.c.
2016
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002017- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002018 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002019
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002020- Fix largefile support on older NetBSD systems and OpenBSD by adding
2021 define for TELL64.
2022
2023
2024Tools and other miscellany
2025
2026- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2027
2028- freeze: The modulefinder now works with 2.0 opcodes.
2029
Tim Petersa3a3a032000-11-30 05:22:44 +00002030- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002031 Move hackery of sys.argv until after the Tk instance has been
2032 created, which allows the application-specific Tkinter
2033 initialization to be executed if present; also pass an explicit
2034 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002035
Jeremy Hylton1b618592000-09-26 05:32:36 +00002036
2037What's new in 2.0 beta 1?
2038=========================
2039
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002040Source Incompatibilities
2041------------------------
2042
2043None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2044such as single-argument append(), connect() and bind(), and changes to
2045str(long) and repr(float).
2046
2047
2048Binary Incompatibilities
2049------------------------
2050
2051- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2052with Python 2.0; these extensions will have to be rebuilt for Python
20532.0.
2054
2055- On Windows, attempting to import a third party extension built for
2056Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2057can do about this. Check your PYTHONPATH environment variable!
2058
2059- Python bytecode files (*.pyc and *.pyo) are not compatible between
2060releases.
2061
2062
2063Overview of Changes Since 1.6
2064-----------------------------
2065
2066There are many new modules (including brand new XML support through
2067the xml package, and i18n support through the gettext module); a list
2068of all new modules is included below. Lots of bugs have been fixed.
2069
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002070The process for making major new changes to the language has changed
2071since Python 1.6. Enhancements must now be documented by a Python
2072Enhancement Proposal (PEP) before they can be accepted.
2073
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002074There are several important syntax enhancements, described in more
2075detail below:
2076
2077 - Augmented assignment, e.g. x += 1
2078
2079 - List comprehensions, e.g. [x**2 for x in range(10)]
2080
2081 - Extended import statement, e.g. import Module as Name
2082
2083 - Extended print statement, e.g. print >> file, "Hello"
2084
2085Other important changes:
2086
2087 - Optional collection of cyclical garbage
2088
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002089Python Enhancement Proposal (PEP)
2090---------------------------------
2091
2092PEP stands for Python Enhancement Proposal. A PEP is a design
2093document providing information to the Python community, or describing
2094a new feature for Python. The PEP should provide a concise technical
2095specification of the feature and a rationale for the feature.
2096
2097We intend PEPs to be the primary mechanisms for proposing new
2098features, for collecting community input on an issue, and for
2099documenting the design decisions that have gone into Python. The PEP
2100author is responsible for building consensus within the community and
2101documenting dissenting opinions.
2102
2103The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002104
2105Augmented Assignment
2106--------------------
2107
2108This must have been the most-requested feature of the past years!
2109Eleven new assignment operators were added:
2110
Guido van Rossume905e952000-09-05 12:42:46 +00002111 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002112
2113For example,
2114
2115 A += B
2116
2117is similar to
2118
2119 A = A + B
2120
2121except that A is evaluated only once (relevant when A is something
2122like dict[index].attr).
2123
2124However, if A is a mutable object, A may be modified in place. Thus,
2125if A is a number or a string, A += B has the same effect as A = A+B
2126(except A is only evaluated once); but if a is a list, A += B has the
2127same effect as A.extend(B)!
2128
2129Classes and built-in object types can override the new operators in
2130order to implement the in-place behavior; the not-in-place behavior is
2131used automatically as a fallback when an object doesn't implement the
2132in-place behavior. For classes, the method name is derived from the
2133method name for the corresponding not-in-place operator by inserting
2134an 'i' in front of the name, e.g. __iadd__ implements in-place
2135__add__.
2136
2137Augmented assignment was implemented by Thomas Wouters.
2138
2139
2140List Comprehensions
2141-------------------
2142
2143This is a flexible new notation for lists whose elements are computed
2144from another list (or lists). The simplest form is:
2145
2146 [<expression> for <variable> in <sequence>]
2147
Guido van Rossum56db0952000-09-06 23:34:25 +00002148For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002149This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002150
2151You can also add a condition:
2152
2153 [<expression> for <variable> in <sequence> if <condition>]
2154
2155For example, [w for w in words if w == w.lower()] would yield the list
2156of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002157than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002158
2159You can also have nested for loops and more than one 'if' clause. For
2160example, here's a function that flattens a sequence of sequences::
2161
2162 def flatten(seq):
2163 return [x for subseq in seq for x in subseq]
2164
2165 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2166
2167This prints
2168
2169 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2170
2171List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002172Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002173
2174
2175Extended Import Statement
2176-------------------------
2177
2178Many people have asked for a way to import a module under a different
2179name. This can be accomplished like this:
2180
2181 import foo
2182 bar = foo
2183 del foo
2184
2185but this common idiom gets old quickly. A simple extension of the
2186import statement now allows this to be written as follows:
2187
2188 import foo as bar
2189
2190There's also a variant for 'from ... import':
2191
2192 from foo import bar as spam
2193
2194This also works with packages; e.g. you can write this:
2195
2196 import test.regrtest as regrtest
2197
2198Note that 'as' is not a new keyword -- it is recognized only in this
2199context (this is only possible because the syntax for the import
2200statement doesn't involve expressions).
2201
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002202Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002203
2204
2205Extended Print Statement
2206------------------------
2207
2208Easily the most controversial new feature, this extension to the print
2209statement adds an option to make the output go to a different file
2210than the default sys.stdout.
2211
2212For example, to write an error message to sys.stderr, you can now
2213write:
2214
2215 print >> sys.stderr, "Error: bad dog!"
2216
2217As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002218evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002219
2220 print >> None, "Hello world"
2221
2222is equivalent to
2223
2224 print "Hello world"
2225
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002226Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002227
2228
2229Optional Collection of Cyclical Garbage
2230---------------------------------------
2231
2232Python is now equipped with a garbage collector that can hunt down
2233cyclical references between Python objects. It's no replacement for
2234reference counting; in fact, it depends on the reference counts being
2235correct, and decides that a set of objects belong to a cycle if all
2236their reference counts can be accounted for from their references to
2237each other. This devious scheme was first proposed by Eric Tiedemann,
2238and brought to implementation by Neil Schemenauer.
2239
2240There's a module "gc" that lets you control some parameters of the
2241garbage collection. There's also an option to the configure script
2242that lets you enable or disable the garbage collection. In 2.0b1,
2243it's on by default, so that we (hopefully) can collect decent user
2244experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002245performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002246off by default in the final 2.0 release.
2247
2248
2249Smaller Changes
2250---------------
2251
2252A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2253map(None, seq1, seq2, ...) when the sequences have the same length;
2254i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2255the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002256zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002257
2258sys.version_info is a tuple (major, minor, micro, level, serial).
2259
2260Dictionaries have an odd new method, setdefault(key, default).
2261dict.setdefault(key, default) returns dict[key] if it exists; if not,
2262it sets dict[key] to default and returns that value. Thus:
2263
2264 dict.setdefault(key, []).append(item)
2265
2266does the same work as this common idiom:
2267
2268 if not dict.has_key(key):
2269 dict[key] = []
2270 dict[key].append(item)
2271
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002272There are two new variants of SyntaxError that are raised for
2273indentation-related errors: IndentationError and TabError.
2274
2275Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2276escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002277
2278The limits on the size of expressions and file in Python source code
2279have been raised from 2**16 to 2**32. Previous versions of Python
2280were limited because the maximum argument size the Python VM accepted
2281was 2**16. This limited the size of object constructor expressions,
2282e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2283limit was raised thanks to a patch by Charles Waldman that effectively
2284fixes the problem. It is now much more likely that you will be
2285limited by available memory than by an arbitrary limit in Python.
2286
2287The interpreter's maximum recursion depth can be modified by Python
2288programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2289limit is the maximum number of recursive calls that can be made by
2290Python code. The limit exists to prevent infinite recursion from
2291overflowing the C stack and causing a core dump. The default value is
22921000. The maximum safe value for a particular platform can be found
2293by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002294
2295New Modules and Packages
2296------------------------
2297
2298atexit - for registering functions to be called when Python exits.
2299
2300imputil - Greg Stein's alternative API for writing custom import
2301hooks.
2302
2303pyexpat - an interface to the Expat XML parser, contributed by Paul
2304Prescod.
2305
2306xml - a new package with XML support code organized (so far) in three
2307subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2308would fill a volume. There's a special feature whereby a
2309user-installed package named _xmlplus overrides the standard
2310xmlpackage; this is intended to give the XML SIG a hook to distribute
2311backwards-compatible updates to the standard xml package.
2312
2313webbrowser - a platform-independent API to launch a web browser.
2314
2315
Guido van Rossume905e952000-09-05 12:42:46 +00002316Changed Modules
2317---------------
2318
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002319array -- new methods for array objects: count, extend, index, pop, and
2320remove
2321
2322binascii -- new functions b2a_hex and a2b_hex that convert between
2323binary data and its hex representation
2324
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002325calendar -- Many new functions that support features including control
2326over which day of the week is the first day, returning strings instead
2327of printing them. Also new symbolic constants for days of week,
2328e.g. MONDAY, ..., SUNDAY.
2329
2330cgi -- FieldStorage objects have a getvalue method that works like a
2331dictionary's get method and returns the value attribute of the object.
2332
2333ConfigParser -- The parser object has new methods has_option,
2334remove_section, remove_option, set, and write. They allow the module
2335to be used for writing config files as well as reading them.
2336
2337ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002338optionally support the RFC 959 REST command.
2339
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002340gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002341
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002342httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2343the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002344
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002345locale -- implement getdefaultlocale for Win32 and Macintosh
2346
2347marshal -- no longer dumps core when marshaling deeply nested or
2348recursive data structures
2349
2350os -- new functions isatty, seteuid, setegid, setreuid, setregid
2351
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002352os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2353support under Unix.
2354
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002355os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002356
2357os.path -- fix semantics of os.path.commonprefix
2358
2359smtplib -- support for sending very long messages
2360
2361socket -- new function getfqdn()
2362
2363readline -- new functions to read, write and truncate history files.
2364The readline section of the library reference manual contains an
2365example.
2366
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002367select -- add interface to poll system call
2368
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002369shutil -- new copyfileobj function
2370
2371SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2372HTTP server.
2373
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002374Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002375
2376urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002377e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002378
2379whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002380
2381
2382Obsolete Modules
2383----------------
2384
2385None. However note that 1.6 made a whole slew of modules obsolete:
2386stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2387poly, zmod, strop, util, whatsound.
2388
2389
2390Changed, New, Obsolete Tools
2391----------------------------
2392
Tim Peters8b092332000-09-05 20:15:25 +00002393None.
Guido van Rossume905e952000-09-05 12:42:46 +00002394
2395
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002396C-level Changes
2397---------------
2398
2399Several cleanup jobs were carried out throughout the source code.
2400
2401All C code was converted to ANSI C; we got rid of all uses of the
2402Py_PROTO() macro, which makes the header files a lot more readable.
2403
2404Most of the portability hacks were moved to a new header file,
2405pyport.h; several other new header files were added and some old
2406header files were removed, in an attempt to create a more rational set
2407of header files. (Few of these ever need to be included explicitly;
2408they are all included by Python.h.)
2409
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002410Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002411and Win64, especially for the new Intel Itanium processor. Mick also
2412added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002413
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002414The C APIs to return an object's size have been update to consistently
2415use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2416previous versions, the abstract interfaces used PyXXX_Length and the
2417concrete interfaces used PyXXX_Size. The old names,
2418e.g. PyObject_Length, are still available for backwards compatibility
2419at the API level, but are deprecated.
2420
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002421The PyOS_CheckStack function has been implemented on Windows by
2422Fredrik Lundh. It prevents Python from failing with a stack overflow
2423on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002424
2425The GC changes resulted in creation of two new slots on object,
2426tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002427the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002428
2429The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002430C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002431
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002432PyErr_Format has been updated to automatically calculate the size of
2433the buffer needed to hold the formatted result string. This change
2434prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002435
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002436New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002437
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002438PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2439that are the same as their non-Ex counterparts except they take an
2440extra flag argument that tells them to close the file when done.
2441
2442XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002443
Tim Peters8b092332000-09-05 20:15:25 +00002444
2445Windows Changes
2446---------------
2447
2448New popen2/popen3/peopen4 in os module (see Changed Modules above).
2449
2450os.popen is much more usable on Windows 95 and 98. See Microsoft
2451Knowledge Base article Q150956. The Win9x workaround described there
2452is implemented by the new w9xpopen.exe helper in the root of your
2453Python installation. Note that Python uses this internally; it is not
2454a standalone program.
2455
2456Administrator privileges are no longer required to install Python
2457on Windows NT or Windows 2000. If you have administrator privileges,
2458Python's registry info will be written under HKEY_LOCAL_MACHINE.
2459Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002460under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002461uses of Python, but will prevent some advanced uses from working
2462(for example, running a Python script as an NT service, or possibly
2463from CGI).
2464
2465[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2466installer; instead, it installs the needed Tcl/Tk files directly in the
2467Python directory. If you already have a Tcl/Tk installation, this
2468wastes some disk space (about 4 Megs) but avoids problems with
2469conflicting Tcl/Tk installations, and makes it much easier for Python
2470to ensure that Tcl/Tk can find all its files.
2471
2472[This was new in 1.6] The Windows installer now installs by default in
2473\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2474
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002475
2476Updates to the changes between 1.5.2 and 1.6
2477--------------------------------------------
2478
2479The 1.6 NEWS file can't be changed after the release is done, so here
2480is some late-breaking news:
2481
2482New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2483and changes to getlocale() and setlocale().
2484
2485The new module is now enabled per default.
2486
2487It is not true that the encodings codecs cannot be used for normal
2488strings: the string.encode() (which is also present on 8-bit strings
2489!) allows using them for 8-bit strings too, e.g. to convert files from
2490cp1252 (Windows) to latin-1 or vice-versa.
2491
2492Japanese codecs are available from Tamito KAJIYAMA:
2493http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2494
2495
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002496======================================================================