blob: 3da64a520411dcba029d12bfafaf8f2705f21b8f [file] [log] [blame]
Tim Petersabf925f2001-09-28 21:53:42 +00001What's New in Python 2.2b1?
2Release date: 28-Sep-2100
3===========================
4
5Type/class unification and new-style classes
6
Guido van Rossum50fda3b2001-10-04 19:46:06 +00007- New-style classes are now dynamic by default. Previous, they were
8 static (meaning class attributes could not be assigned to) and
9 dynamic classes had to be requested by adding __dynamic__ = 1 to the
10 body of the class or to the module. Static classes are faster than
11 dynamic classes, but dynamic classes are now at most 50% slower than
12 static classes; previously, they could be up to 10x slower. (This
13 was accomplished by making dynamic classes faster, not by making
14 static classes slower. :-) Note that according to one benchmark,
15 static classes are about the same speed as classic classes.
16
Tim Peters1c9ca872001-10-04 06:43:12 +000017- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
18 always returned None, even when there was a class docstring).
19
20- doctest now finds and runs docstrings attached to new-style classes,
21 class methods, static methods, and properties.
22
Tim Petersabf925f2001-09-28 21:53:42 +000023Core
24
Martin v. Löwis16dc7f42001-09-30 20:32:11 +000025- binascii has now two quopri support functions, a2b_qp and b2a_qp.
26
Martin v. Löwis0daad592001-09-30 21:09:59 +000027- readline now supports setting the startup_hook and the pre_event_hook.
28
Martin v. Löwis16628c92001-10-04 22:46:41 +000029- posix supports chroot where available.
30
Tim Petersabf925f2001-09-28 21:53:42 +000031Library
32
Tim Peters7402f792001-10-02 03:53:41 +000033- doctest now excludes functions and classes not defined by the module
34 being tested, thanks to Tim Hochberg.
35
Guido van Rossumc4b09b42001-10-04 10:19:00 +000036- profile now produces correct output in situations where an exception
37 raised in Python is cleared by C code (e.g. hasattr()). This used
38 to cause wrong output, including spurious claims of recursive
39 functions and attribution of time spent to the wrong function.
40
Tim Peters0a1fc4e2001-10-07 03:12:08 +000041 The code and documentation for the derived OldProfile and HotProfile
42 profiling classes was removed. The code hasn't worked for years (if
43 you tried to use them, they raised exceptions). OldProfile
44 intended to reproduce the behavior of the profiler Python used more
45 than 7 years ago, and isn't interesting anymore. HotProfile intended
46 to provide a faster profiler (but producing less information), and
47 that's a worthy goal we intend to meet via a different approach (but
48 without losing information).
49
Tim Peterscce092d2001-10-09 05:31:56 +000050- Profile.calibrate() has a new implementation that should deliver
51 a better system-specific calibration constant. Calibration must still
52 be done manually (see the docs for the profile module).
53
Martin v. Löwis16dc7f42001-09-30 20:32:11 +000054- quopri's encode and decode methods take an optional header parameter,
55 which indicates whether output is intended for the header 'Q' encoding.
56
Guido van Rossumed554f62001-10-02 23:15:37 +000057Tools/Demos
58
59- Demo/dns was removed. It no longer serves any purpose; a package
60 derived from it is now maintained by Anthony Baxter, see
61 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +000062
63Build
64
65C API
66
Tim Petersd38b1c72001-09-30 05:09:37 +000067- PyLong_AsLongLong() now accepts int (as well as long) arguments.
68 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
69 as long) arguments.
70
Tim Petersabf925f2001-09-28 21:53:42 +000071New platforms
72
73Tests
74
75Windows
76
Tim Peters1ce3cf72001-10-01 17:58:40 +000077- The signal module now supports SIGBREAK on Windows, thanks to Steven
78 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
79 action remains to call Win32 ExitProcess(). This can be changed via
80 signal.signal(). For example:
81
82 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
83 # (SIGINT) behavior.
84 import signal
85 signal.signal(signal.SIGBREAK,
86 signal.default_int_handler)
87
88 try:
89 while 1:
90 pass
91 except KeyboardInterrupt:
92 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
93 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
94 # program without the possibility for any Python-level cleanup).
95 print "Clean exit"
96
Tim Petersabf925f2001-09-28 21:53:42 +000097
Tim Petersb07352e2001-09-08 01:25:47 +000098What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +000099Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +0000100===========================
101
Guido van Rossum808eea72001-09-25 04:15:41 +0000102Type/class unification and new-style classes
103
104- pydoc and inspect are now aware of new-style classes;
105 e.g. help(list) at the interactive prompt now shows proper
106 documentation for all operations on list objects.
107
108- Applications using Jim Fulton's ExtensionClass module can now safely
109 be used with Python 2.2. In particular, Zope 2.4.1 now works with
110 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
111 examples also work again. It is hoped that Gtk and Boost also work
112 with 2.2a4 and beyond. (If you can confirm this, please write
113 webmaster@python.org; if there are still problems, please open a bug
114 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000115
Tim Peters66c1a522001-09-24 21:17:50 +0000116- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
117 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
118 in the constructed property object. fget, fset and fdel weren't
119 discoverable from Python in 2.2a3. __doc__ is new, and allows to
120 associate a docstring with a property.
121
Guido van Rossum808eea72001-09-25 04:15:41 +0000122- Comparison overloading is now more completely implemented. For
123 example, a str subclass instance can properly be compared to a str
124 instance, and it can properly overload comparison. Ditto for most
125 other built-in object types.
126
127- The repr() of new-style classes has changed; instead of <type
128 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
129 *except* for built-in types, which are still rendered as <type
130 'Foo'> (to avoid upsetting existing code that might parse or
131 otherwise rely on repr() of certain type objects).
132
133- The repr() of new-style objects is now always <Foo object at XXX>;
134 previously, it was sometimes <Foo instance at XXX>.
135
136- For new-style classes, what was previously called __getattr__ is now
137 called __getattribute__. This method, if defined, is called for
138 *every* attribute access. A new __getattr__ hook mor similar to the
139 one in classic classes is defined which is called only if regular
140 attribute access raises AttributeError; to catch *all* attribute
141 access, you can use __getattribute__ (for new-style classes). If
142 both are defined, __getattribute__ is called first, and if it raises
143 AttributeError, __getattr__ is called.
144
145- The __class__ attribute of new-style objects can be assigned to.
146 The new class must have the same C-level object layout as the old
147 class.
148
149- The builtin file type can be subclassed now. In the usual pattern,
150 "file" is the name of the builtin type, and file() is a new builtin
151 constructor, with the same signature as the builtin open() function.
152 file() is now the preferred way to open a file.
153
154- Previously, __new__ would only see sequential arguments passed to
155 the type in a constructor call; __init__ would see both sequential
156 and keyword arguments. This made no sense whatsoever any more, so
157 now both __new__ and __init__ see all arguments.
158
159- Previously, hash() applied to an instance of a subclass of str or
160 unicode always returned 0. This has been repaired.
161
162- Previously, an operation on an instance of a subclass of an
163 immutable type (int, long, float, complex, tuple, str, unicode),
164 where the subtype didn't override the operation (and so the
165 operation was handled by the builtin type), could return that
166 instance instead a value of the base type. For example, if s was of
167 a str sublass type, s[:] returned s as-is. Now it returns a str
168 with the same value as s.
169
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000170- Provisional support for pickling new-style objects has been added.
171
Guido van Rossum808eea72001-09-25 04:15:41 +0000172Core
173
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000174- file.writelines() now accepts any iterable object producing strings.
175
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000176- PyUnicode_FromEncodedObject() now works very much like
177 PyObject_Str(obj) in that it tries to use __str__/tp_str
178 on the object if the object is not a string or buffer. This
179 makes unicode() behave like str() when applied to non-string/buffer
180 objects.
181
Martin v. Löwis2777c022001-09-19 13:47:32 +0000182- PyFile_WriteObject now passes Unicode object to the file's write
183 method. As a result, all file-like object which may be the target
184 of a print statement must support Unicode objects, i.e. they must
185 at least convert them into ASCII strings.
186
Guido van Rossum624c8af2001-09-18 15:21:04 +0000187- Thread scheduling on Solaris should be improved; it is no longer
188 necessary to insert a small sleep at the start of a thread in order
189 to let other runnable threads be scheduled.
190
Tim Petersb07352e2001-09-08 01:25:47 +0000191Library
192
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000193- StringIO.StringIO instances and cStringIO.StringIO instances support
194 read character buffer compatible objects for their .write() methods.
195 These objects are converted to strings and then handled as such
196 by the instances.
197
Barry Warsaw2f600732001-09-24 04:28:10 +0000198- The "email" package has been added. This is basically a port of the
199 mimelib package <http://sf.net/projects/mimelib> with API changes
200 and some implementations updated to use iterators and generators.
201
Tim Peters8a9c2842001-09-22 21:30:22 +0000202- difflib.ndiff() and difflib.Differ.compare() are generators now. This
203 restores the ability of Tools/scripts/ndiff.py to start producing output
204 before the entire comparison is complete.
205
Barry Warsaw58b072d2001-09-22 04:44:21 +0000206- StringIO.StringIO instances and cStringIO.StringIO instances support
207 iteration just like file objects (i.e. their .readline() method is
208 called for each iteration until it returns an empty string).
209
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000210- The codecs module has grown four new helper APIs to access
211 builtin codecs: getencoder(), getdecoder(), getreader(),
212 getwriter().
213
Guido van Rossum624c8af2001-09-18 15:21:04 +0000214- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
215 simplifies writing XML RPC servers.
216
Barry Warsaw647d5e82001-09-28 17:01:02 +0000217- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000218 after interpretation of symbolic links. On non-Unix systems, this
219 is an alias for os.path.abspath().
220
Tim Peters16a77ad2001-09-08 04:00:12 +0000221- operator.indexOf() (PySequence_Index() in the C API) now works with any
222 iterable object.
223
Guido van Rossum624c8af2001-09-18 15:21:04 +0000224- smtplib now supports various authentication and security features of
225 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000226
Guido van Rossum624c8af2001-09-18 15:21:04 +0000227- hmac: a new module implementing keyed hashing for message
228 authentication.
229
230- mimetypes now recognizes more extensions and file types. At the
231 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000232
Guido van Rossum624c8af2001-09-18 15:21:04 +0000233- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000234 Python 2.2 bytecode generation. It has also been promoted from a
235 Tool to a standard library package. (Tools/compiler still exists as
236 a sample driver.)
237
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000238Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000239
Tim Petersb07352e2001-09-08 01:25:47 +0000240Build
241
Guido van Rossum624c8af2001-09-18 15:21:04 +0000242- Large file support (LFS) is now automatic when the platform supports
243 it; no more manual configuration tweaks are needed. On Linux, at
244 least, it's possible to have a system whose C library supports large
245 files but whose kernel doesn't; in this case, large file support is
246 still enabled but doesn't do you any good unless you upgrade your
247 kernel or share your Python executable with another system whose
248 kernel has large file support.
249
250- The configure script now supplies plausible defaults in a
251 cross-compilation environment. This doesn't mean that the supplied
252 values are always correct, or that cross-compilation now works
253 flawlessly -- but it's a first step (and it shuts up most of
254 autoconf's warnings about AC_TRY_RUN).
255
256- The Unix build is now a bit less chatty, courtesy of the parser
257 generator. The build is completely silent (except for errors) when
258 using "make -s", thanks to a -q option to setup.py.
259
Tim Petersb07352e2001-09-08 01:25:47 +0000260C API
261
Guido van Rossum624c8af2001-09-18 15:21:04 +0000262- The "structmember" API now supports some new flag bits to deny read
263 and/or write access to attributes in restricted execution mode.
264
Tim Petersb07352e2001-09-08 01:25:47 +0000265New platforms
266
Guido van Rossum624c8af2001-09-18 15:21:04 +0000267- Compaq's iPAQ handheld, running the "familiar" Linux distribution
268 (http://familiar.handhelds.org).
269
Tim Petersb07352e2001-09-08 01:25:47 +0000270Tests
271
Tim Peters8a9c2842001-09-22 21:30:22 +0000272- The "classic" standard tests, which work by comparing stdout to
273 an expected-output file under Lib/test/output/, no longer stop at
274 the first mismatch. Instead the test is run to completion, and a
275 variant of ndiff-style comparison is used to report all differences.
276 This is much easier to understand than the previous style of reporting.
277
278- The unittest-based standard tests now use regrtest's test_main()
279 convention, instead of running as a side-effect of merely being
280 imported. This allows these tests to be run in more natural and
281 flexible ways as unittests, outside the regrtest framework.
282
283- regrtest.py is much better integrated with unittest and doctest now,
284 especially in regard to reporting errors.
285
Tim Petersb07352e2001-09-08 01:25:47 +0000286Windows
287
Guido van Rossum624c8af2001-09-18 15:21:04 +0000288- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000289 that support it (NTFS under Windows 2000). See "What's New in
290 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000291
Tim Petersb07352e2001-09-08 01:25:47 +0000292
Tim Petersedc99312001-08-22 21:36:50 +0000293What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000294Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000295===========================
296
297Core
298
Tim Peters9fffa3e2001-09-04 05:14:19 +0000299- Conversion of long to float now raises OverflowError if the long is too
300 big to represent as a C double.
301
Tim Peters32f453e2001-09-03 08:35:41 +0000302- The 3-argument builtin pow() no longer allows a third non-None argument
303 if either of the first two arguments is a float, or if both are of
304 integer types and the second argument is negative (in which latter case
305 the arguments are converted to float, so this is really the same
306 restriction).
307
Tim Peters5d2b77c2001-09-03 05:47:38 +0000308- The builtin dir() now returns more information, and sometimes much
309 more, generally naming all attributes of an object, and all attributes
310 reachable from the object via its class, and from its class's base
311 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
312 an empty list. In 2.2a3,
313
314 >>> dir([])
315 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
316 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
317 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
318 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
319 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
320 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
321 'reverse', 'sort']
322
323 dir(module) continues to return only the module's attributes, though.
324
Tim Petersbdee63f2001-09-02 03:40:59 +0000325- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000326 than raising OverflowError. This is a partial implementation of PEP
327 237. You can use -Wdefault::OverflowWarning to enable a warning for
328 this situation, and -Werror::OverflowWarning to revert to the old
329 OverflowError exception.
330
Guido van Rossum61c345f2001-09-04 03:26:15 +0000331- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000332 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000333 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
334 -Qold, meaning the / operator has its classic meaning and no
335 warnings are issued. Using -Qwarn issues a run-time warning about
336 all uses of classic division for int and long arguments; -Qwarnall
337 also warns about classic division for float and complex arguments
338 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
339 new division by default, but only in the __main__ module. You can
340 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
341 __main__ module new division, and warns about classic division
342 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000343
Tim Petersbdee63f2001-09-02 03:40:59 +0000344- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000345 long, float, str, unicode, and tuple. (The types complex, list and
346 dictionary can also be subclassed; this was introduced earlier.)
347 Note that restrictions apply when subclassing immutable built-in
348 types: you can only affect the value of the instance by overloading
349 __new__. You can add mutable attributes, and the subclass instances
350 will have a __dict__ attribute, but you cannot change the "value"
351 (as implemented by the base class) of an immutable subclass instance
352 once it is created.
353
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000354- The dictionary constructor now takes an optional argument, a
355 mapping-like object, and initializes the dictionary from its
356 (key, value) pairs.
357
Tim Petersbdee63f2001-09-02 03:40:59 +0000358- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000359 "cooperative super calls" in a multiple inheritance setting. For an
360 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
361
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000362- A new built-in type, property, has been added. This enables the
363 creation of "properties". These are attributes implemented by
364 getter and setter functions (or only one of these for read-only or
365 write-only attributes), without the need to override __getattr__.
366 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000367
Tim Petersbdee63f2001-09-02 03:40:59 +0000368- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000369 liberalized, to allow leading zeroes. Examples of literals now
370 legal that were SyntaxErrors before:
371
372 00.0 0e3 0100j 07.5 00000000000000000008.
373
Tim Petersbdee63f2001-09-02 03:40:59 +0000374- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000375 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
376
Tim Petersedc99312001-08-22 21:36:50 +0000377Library
378
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000379- telnetlib includes symbolic names for the options, and support for
380 setting an option negotiation callback.
381
Tim Petersa40c7932001-09-05 22:36:56 +0000382- The new C standard no longer requires that math libraries set errno to
383 ERANGE on overflow. For platform libraries that exploit this new
384 freedom, Python's overflow-checking was wholly broken. A new overflow-
385 checking scheme attempts to repair that, but may not be reliable on all
386 platforms (C doesn't seem to provide anything both useful and portable
387 in this area anymore).
388
Martin v. Löwis44f86962001-09-05 13:44:54 +0000389- Asynchronous timeout actions are available through the new class
390 threading.Timer.
391
Tim Peters78526162001-09-05 00:53:45 +0000392- math.log and math.log10 now return sensible results for even huge
393 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
394
Tim Petersbdee63f2001-09-02 03:40:59 +0000395- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000396 currently held. See the docs for the imp module.
397
Tim Petersbdee63f2001-09-02 03:40:59 +0000398- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000399 dumps containing ints written on platforms where Python ints are 8 bytes.
400 When read on a box where Python ints are 4 bytes, such values are
401 converted to Python longs.
402
Tim Petersbdee63f2001-09-02 03:40:59 +0000403- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000404 code objects is no longer allowed. This plugs a security hole.
405
Steve Purcell6091cd62001-09-06 16:05:17 +0000406- unittest.TestResult instances no longer store references to tracebacks
407 generated by test failures. This prevents unexpected dangling references
408 to objects that should be garbage collected between tests.
409
Tim Petersedc99312001-08-22 21:36:50 +0000410Tools
411
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000412- Tools/scripts/fixdiv.py has been added which can be used to fix
413 division operators as per PEP 238.
414
Tim Petersedc99312001-08-22 21:36:50 +0000415Build
416
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000417- If you are an adventurous person using Mac OS X you may want to look at
418 Mac/OSX. There is a Makefile there that will build Python as a real Mac
419 application, which can be used for experimenting with Carbon or Cocoa.
420 Discussion of this on pythonmac-sig, please.
421
Tim Peters7eea37e2001-09-04 22:08:56 +0000422C API
423
424- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000425
Tim Peters9fffa3e2001-09-04 05:14:19 +0000426- Note that PyLong_AsDouble can fail! This has always been true, but no
427 callers checked for it. It's more likely to fail now, because overflow
428 errors are properly detected now. The proper way to check:
429
430 double x = PyLong_AsDouble(some_long_object);
431 if (x == -1.0 && PyErr_Occurred()) {
432 /* The conversion failed. */
433 }
434
Tim Petersbdee63f2001-09-02 03:40:59 +0000435- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000436 compile but will not participate in GC. To upgrade an extension
437 module:
438
439 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000440
Neil Schemenauer4042c692001-08-30 15:38:01 +0000441 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
442 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000443
Neil Schemenauer4042c692001-08-30 15:38:01 +0000444 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
445 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000446
Neil Schemenauer4042c692001-08-30 15:38:01 +0000447 - remove PyGC_HEAD_SIZE from object size calculations
448
449 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
450
Tim Petersbdee63f2001-09-02 03:40:59 +0000451- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000452 These can be used safely to construct string objects from a
453 sprintf-style format string (similar to the format string supported
454 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000455
Tim Petersedc99312001-08-22 21:36:50 +0000456New platforms
457
Tim Petersb7da0902001-09-02 23:01:43 +0000458- Stephen Hansen contributed patches sufficient to get a clean compile
459 under Borland C (Windows), but he reports problems running it and ran
460 out of time to complete the port. Volunteers? Expect a MemoryError
461 when importing the types module; this is probably shallow, and
462 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000463
Tim Petersedc99312001-08-22 21:36:50 +0000464Tests
465
466Windows
467
Tim Peters6e13a562001-09-06 00:32:15 +0000468- Large file support is now enabled on Win32 platforms as well as on
469 Win64. This means that, for example, you can use f.tell() and f.seek()
470 to manipulate files larger than 2 gigabytes (provided you have enough
471 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000472 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
473 filesize limit, and large file support makes no difference there.
474 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
475 NTFS has no practical limit on file size, and files of any size can be
476 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000477
Tim Petersbdee63f2001-09-02 03:40:59 +0000478- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000479 points to command.com (patch from Brian Quinlan).
480
Tim Petersedc99312001-08-22 21:36:50 +0000481
Tim Peters20f51a72001-07-21 02:31:40 +0000482What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000483Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000484===========================
485
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000486Build
487
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000488- Tim Peters developed a brand new Windows installer using Wise 8.1,
489 generously donated to us by Wise Solutions.
490
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000491- configure supports a new option --enable-unicode, with the values
492 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
493 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000494
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000495- A new configure option --enable-framework builds a Mac OS X framework,
496 which "make frameworkinstall" will install. This provides a starting
497 point for more mac-like functionality, join pythonmac-sig@python.org
498 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000499
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000500- The NeXT platform is no longer supported.
501
502- The `new' module is now statically linked.
503
Tim Peters0afb6092001-08-15 06:06:44 +0000504Tools
505
506- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000507 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000508 the module docstring for details.
509
Tim Peters20f51a72001-07-21 02:31:40 +0000510Tests
511
Tim Peters5e824c32001-08-12 22:25:01 +0000512- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000513 platforms, allowing to give clearer test result output. regrtest
514 also has optional --use/-u switch to run normally disabled tests
515 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000516
Tim Peters20f51a72001-07-21 02:31:40 +0000517- Several new tests in the standard test suite, with special thanks to
518 Nick Mathewson.
519
520Core
521
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000522- The floor division operator // has been added as outlined in PEP
523 238. The / operator still provides classic division (and will until
524 Python 3.0) unless "from __future__ import division" is included, in
525 which case the / operator will provide true division. The operator
526 module provides truediv() and floordiv() functions. Augmented
527 assignment variants are included, as are the equivalent overloadable
528 methods and C API methods. See the PEP for a full discussion:
529 <http://python.sf.net/peps/pep-0238.html>
530
Tim Peters6cd6a822001-08-17 22:11:27 +0000531- Future statements are now effective in simulated interactive shells
532 (like IDLE). This should "just work" by magic, but read Michael
533 Hudson's "Future statements in simulated shells" PEP 264 for full
534 details: <http://python.sf.net/peps/pep-0264.html>.
535
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000536- The type/class unification (PEP 252-253) was integrated into the
537 trunk and is not so tentative any more (the exact specification of
538 some features is still tentative). A lot of work has done on fixing
539 bugs and adding robustness and features (performance still has to
540 come a long way).
541
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000542- Warnings about a mismatch in the Python API during extension import
543 now use the Python warning framework (which makes it possible to
544 write filters for these warnings).
545
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000546- A function's __dict__ (aka func_dict) will now always be a
547 dictionary. It used to be possible to delete it or set it to None,
548 but now both actions raise TypeErrors. It is still legal to set it
549 to a dictionary object. Getting func.__dict__ before any attributes
550 have been assigned now returns an empty dictionary instead of None.
551
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000552- A new command line option, -E, was added which disables the use of
553 all environment variables, or at least those that are specifically
554 significant to Python. Usually those have a name starting with
555 "PYTHON". This was used to fix a problem where the tests fail if
556 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
557 older distribution.
558
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000559Library
560
Tim Peters5e824c32001-08-12 22:25:01 +0000561- New class Differ and new functions ndiff() and restore() in difflib.py.
562 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000563 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000564
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000565- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
566 value using the minimal quoting required for the value; more
567 reliable than using xml.sax.saxutils.escape() for attribute values.
568
569- Readline completion support for cmd.Cmd was added.
570
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000571- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
572
573- Added function threading.BoundedSemaphore()
574
575- Added Ka-Ping Yee's cgitb.py module.
576
577- The `new' module now exposes the CO_xxx flags.
578
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000579New platforms
580
581C API
582
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000583- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
584 which provide a cross-platform implementations for the
585 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
586 the standard sprintf() and vsprintf() C lib APIs, these versions
587 apply bounds checking on the used buffer which enhances protection
588 against buffer overruns.
589
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000590- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000591 and extensions using different Unicode widths is rendered next to
592 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000593 will result in an ImportError. Unicode extensions writers must make
594 sure to check the Unicode width compatibility in their extensions by
595 using at least one of the mangled Unicode APIs in the extension.
596
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000597- Two new flags METH_NOARGS and METH_O are available in method definition
598 tables to simplify implementation of methods with no arguments and a
599 single untyped argument. Calling such methods is more efficient than
600 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
601 deprecated.
602
Tim Petersc1731372001-08-04 08:12:36 +0000603Windows
604
605- "import module" now compiles module.pyw if it exists and nothing else
606 relevant is found.
607
Tim Peters20f51a72001-07-21 02:31:40 +0000608
Guido van Rossum55a78992001-07-17 17:22:32 +0000609What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +0000610===========================
611
612Core
Tim Petersa814db52001-05-14 07:05:58 +0000613
Tim Peters6d6c1a32001-08-02 04:15:00 +0000614- TENTATIVELY, a large amount of code implementing much of what's
615 described in PEP 252 (Making Types Look More Like Classes) and PEP
616 253 (Subtyping Built-in Types) was added. This will be released
617 with Python 2.2a1. Documentation will be provided separately
618 through http://www.python.org/2.2/. The purpose of releasing this
619 with Python 2.2a1 is to test backwards compatibility. It is
620 possible, though not likely, that a decision is made not to release
621 this code as part of 2.2 final, if any serious backwards
622 incompapatibilities are found during alpha testing that cannot be
623 repaired.
624
Guido van Rossum55a78992001-07-17 17:22:32 +0000625- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000626 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000627 more 'yield' statements. See PEP 255. Since this adds a new
628 keyword to the language, this feature must be enabled by including a
629 future statement: "from __future__ import generators" (see PEP 236).
630 Generators will become a standard feature in a future release
631 (probably 2.3). Without this future statement, 'yield' remains an
632 ordinary identifier, but a warning is issued each time it is used.
633 (These warnings currently don't conform to the warnings framework of
634 PEP 230; we intend to fix this in 2.2a2.)
635
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000636- The UTF-16 codec was modified to be more RFC compliant. It will now
637 only remove BOM characters at the start of the string and then
638 only if running in native mode (UTF-16-LE and -BE won't remove a
639 leading BMO character).
640
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000641- Strings now have a new method .decode() to complement the already
642 existing .encode() method. These two methods provide direct access
643 to the corresponding decoders and encoders of the registered codecs.
644
645 To enhance the usability of the .encode() method, the special
646 casing of Unicode object return values was dropped (Unicode objects
647 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000648
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000649 Both methods will now return whatever the codec in charge of the
650 requested encoding returns as object, e.g. Unicode codecs will
651 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
652 will return u"äöü"). This enables codec writer to create codecs
653 for various simple to use conversions.
654
655 New codecs were added to demonstrate these new features (the .encode()
656 and .decode() columns indicate the type of the returned objects):
657
658 Name | .encode() | .decode() | Description
659 ----------------------------------------------------------------------
660 uu | string | string | UU codec (e.g. for email)
661 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000662 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000663 zlib | string | string | zlib compression
664 hex | string | string | 2-byte hex codec
665 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
666
Mark Hammond2a0af792001-05-14 03:09:36 +0000667- Some operating systems now support the concept of a default Unicode
668 encoding for file system operations. Notably, Windows supports 'mbcs'
669 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000670 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000671 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000672
673 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000674 functions that return filenames (such as os.listdir()) to return Python
675 string objects pre-encoded using the default file system encoding for
676 the platform. As this encoding is likely to be different from Python's
677 default encoding, converting this name to a Unicode object before passing
678 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000679 would attempt to use its default encoding (generally ASCII) rather than
680 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000681
Tim Petersa814db52001-05-14 07:05:58 +0000682 In general, this change simply removes surprises when working with
683 Unicode and the file system, making these operations work as you expect,
684 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000685 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000686
Tim Peters61dff2b2001-05-08 15:43:37 +0000687- Float (and complex) literals in source code were evaluated to full
688 precision only when running from a .py file; the same code loaded from a
689 .pyc (or .pyo) file could suffer numeric differences starting at about the
690 12th significant decimal digit. For example, on a machine with IEEE-754
691 floating arithmetic,
692
693 x = 9007199254740992.0
694 print long(x)
695
696 printed 9007199254740992 if run directly from .py, but 9007199254740000
697 if from a compiled (.pyc or .pyo) file. This was due to marshal using
698 str(float) instead of repr(float) when building code objects. marshal
699 now uses repr(float) instead, which should reproduce floats to full
700 machine precision (assuming the platform C float<->string I/O conversion
701 functions are of good quality).
702
703 This may cause floating-point results to change in some cases, and
704 usually for the better, but may also cause numerically unstable
705 algorithms to break.
706
Tim Peters2f228e72001-05-13 00:19:31 +0000707- The implementation of dicts suffers fewer collisions, which has speed
708 benefits. However, the order in which dict entries appear in dict.keys(),
709 dict.values() and dict.items() may differ from previous releases for a
710 given dict. Nothing is defined about this order, so no program should
711 rely on it. Nevertheless, it's easy to write test cases that rely on the
712 order by accident, typically because of printing the str() or repr() of a
713 dict to an "expected results" file. See Lib/test/test_support.py's new
714 sortdict(dict) function for a simple way to display a dict in sorted
715 order.
716
Tim Peters7a3bfc32001-06-12 01:22:22 +0000717- Many other small changes to dicts were made, resulting in faster
718 operation along the most common code paths.
719
Guido van Rossum10315822001-05-01 20:54:30 +0000720- Dictionary objects now support the "in" operator: "x in dict" means
721 the same as dict.has_key(x).
722
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000723- The update() method of dictionaries now accepts generic mapping
724 objects. Specifically the argument object must support the .keys()
725 and __getitem__() methods. This allows you to say, for example,
726 {}.update(UserDict())
727
Guido van Rossum10315822001-05-01 20:54:30 +0000728- Iterators were added; this is a generalized way of providing values
729 to a for loop. See PEP 234. There's a new built-in function iter()
730 to return an iterator. There's a new protocol to get the next value
731 from an iterator using the next() method (in Python) or the
732 tp_iternext slot (in C). There's a new protocol to get iterators
733 using the __iter__() method (in Python) or the tp_iter slot (in C).
734 Iterating (i.e. a for loop) over a dictionary generates its keys.
735 Iterating over a file generates its lines.
736
Tim Petersf553f892001-05-01 20:45:31 +0000737- The following functions were generalized to work nicely with iterator
738 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000739 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000740 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
741 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000742 join() method of strings
743 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000744 'x in y' and 'x not in y' (PySequence_Contains() in C API)
745 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000746 right-hand side of assignment statements with multiple targets, such as
747 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000748
Tim Petersd85e1022001-05-11 21:51:48 +0000749- Accessing module attributes is significantly faster (for example,
750 random.random or os.path or yourPythonModule.yourAttribute).
751
Tim Peterse63415e2001-05-08 04:38:29 +0000752- Comparing dictionary objects via == and != is faster, and now works even
753 if the keys and values don't support comparisons other than ==.
754
Tim Peters95bf9392001-05-10 08:32:44 +0000755- Comparing dictionaries in ways other than == and != is slower: there were
756 insecurities in the dict comparison implementation that could cause Python
757 to crash if the element comparison routines for the dict keys and/or
758 values mutated the dicts. Making the code bulletproof slowed it down.
759
Tim Peterseb28ef22001-06-02 05:27:19 +0000760- Collisions in dicts are resolved via a new approach, which can help
761 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000762 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000763 faster now. Thanks to Christian Tismer for pointing out the cause and
764 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000765
Tim Peters52e155e2001-06-16 05:42:57 +0000766- repr() is much faster for large containers (dict, list, tuple).
767
768
Tim Petersa814db52001-05-14 07:05:58 +0000769Library
770
Fred Drake960fdf92001-07-20 18:38:26 +0000771- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
772 were added to the string module. These a locale-indenpendent
773 constants, unlike letters, lowercase, and uppercase. These are now
774 use in appropriate locations in the standard library.
775
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000776- The flags used in dlopen calls can now be configured using
777 sys.setdlopenflags and queried using sys.getdlopenflags.
778
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000779- Fredrik Lundh's xmlrpclib is now a standard library module. This
780 provides full client-side XML-RPC support. In addition,
781 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
782 one asyncore-based). Thanks to Eric Raymond for the documentation.
783
Guido van Rossum643d3912001-07-05 14:46:25 +0000784- The xrange() object is simplified: it no longer supports slicing,
785 repetition, comparisons, efficient 'in' checking, the tolist()
786 method, or the start, stop and step attributes. See PEP 260.
787
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000788- A new function fnmatch.filter to filter lists of file names was added.
789
Barry Warsawffd674d2001-05-22 16:00:10 +0000790- calendar.py uses month and day names based on the current locale.
791
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000792- strop is now *really* obsolete (this was announced before with 1.6),
793 and issues DeprecationWarning when used (except for the four items
794 that are still imported into string.py).
795
Tim Petersa814db52001-05-14 07:05:58 +0000796- Cookie.py now sorts key+value pairs by key in output strings.
797
798- pprint.isrecursive(object) didn't correctly identify recursive objects.
799 Now it does.
800
Tim Peters95b3f782001-05-14 18:39:41 +0000801- pprint functions now much faster for large containers (tuple, list, dict).
802
Tim Peters7b9542a2001-06-10 23:40:19 +0000803- New 'q' and 'Q' format codes in the struct module, corresponding to C
804 types "long long" and "unsigned long long" (on Windows, __int64). In
805 native mode, these can be used only when the platform C compiler supports
806 these types (when HAVE_LONG_LONG is #define'd by the Python config
807 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000808 In standard mode, 'q' and 'Q' are supported on all platforms, and are
809 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000810
Guido van Rossum83213cc2001-06-12 16:48:52 +0000811- The site module installs a new built-in function 'help' that invokes
812 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
813 it displays a message reminding the user to use 'help()' or
814 'help(object)'.
815
Tim Petersa814db52001-05-14 07:05:58 +0000816Tests
817
818- New test_mutants.py runs dict comparisons where the key and value
819 comparison operators mutute the dicts randomly during comparison. This
820 rapidly causes Python to crash under earlier releases (not for the faint
821 of heart: it can also cause Win9x to freeze or reboot!).
822
823- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000824 pprint.isreadable() return sensible results. Also verifies that simple
825 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000826
Tim Peters4324aa32001-05-28 22:30:08 +0000827C API
828
829- Removed the unused last_is_sticky argument from the internal
830 _PyTuple_Resize(). If this affects you, you were cheating.
831
832
Guido van Rossum55a78992001-07-17 17:22:32 +0000833======================================================================
834
835
Guido van Rossumffe13be2001-04-16 18:46:45 +0000836What's New in Python 2.1 (final)?
837=================================
838
839We only changed a few things since the last release candidate, all in
840Python library code:
841
842- A bug in the locale module was fixed that affected locales which
843 define no grouping for numeric formatting.
844
845- A few bugs in the weakref module's implementations of weak
846 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
847 and the test suite was updated to check for these bugs.
848
849- An old bug in the os.path.walk() function (introduced in Python
850 2.0!) was fixed: a non-existent file would cause an exception
851 instead of being ignored.
852
853- Fixed a few bugs in the new symtable module found by Neil Norwitz's
854 PyChecker.
855
856
Guido van Rossum5b08f132001-04-16 02:05:23 +0000857What's New in Python 2.1c2?
858===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000859
Guido van Rossum5b08f132001-04-16 02:05:23 +0000860A flurry of small changes, and one showstopper fixed in the nick of
861time made it necessary to release another release candidate. The list
862here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000863
Guido van Rossum5b08f132001-04-16 02:05:23 +0000864Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000865
Guido van Rossum5b08f132001-04-16 02:05:23 +0000866- Tim discovered a nasty bug in the dictionary code, caused by
867 PyDict_Next() calling dict_resize(), and the GC code's use of
868 PyDict_Next() violating an assumption in dict_items(). This was
869 fixed with considerable amounts of band-aid, but the net effect is a
870 saner and more robust implementation.
871
872- Made a bunch of symbols static that were accidentally global.
873
874Build and Ports
875
876- The setup.py script didn't check for a new enough version of zlib
877 (1.1.3 is needed). Now it does.
878
879- Changed "make clean" target to also remove shared libraries.
880
881- Added a more general warning about the SGI Irix optimizer to README.
882
883Library
884
885- Fix a bug in urllib.basejoin("http://host", "../file.html") which
886 omitted the slash between host and file.html.
887
888- The mailbox module's _Mailbox class contained a completely broken
889 and undocumented seek() method. Ripped it out.
890
891- Fixed a bunch of typos in various library modules (urllib2, smtpd,
892 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
893
894- Fixed a few last-minute bugs in unittest.
895
896Extensions
897
898- Reverted the patch to the OpenSSL code in socketmodule.c to support
899 RAND_status() and the EGD, and the subsequent patch that tried to
900 fix it for pre-0.9.5 versions; the problem with the patch is that on
901 some systems it issues a warning whenever socket is imported, and
902 that's unacceptable.
903
904Tests
905
906- Fixed the pickle tests to work with "import test.test_pickle".
907
908- Tweaked test_locale.py to actually run the test Windows.
909
910- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
911 not "wb" (which is not a valid mode at all).
912
913- Fix pstats browser crashes. Import readline if it exists to make
914 the user interface nicer.
915
916- Add "import thread" to the top of test modules that import the
917 threading module (test_asynchat and test_threadedtempfile). This
918 prevents test failures caused by a broken threading module resulting
919 from a previously caught failed import.
920
921- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
922 needed on some platforms (e.g. Solaris 8) when the tests are run
923 twice in succession.
924
925- Skip rather than fail test_sunaudiodev if no audio device is found.
926
927
928What's New in Python 2.1c1?
929===========================
930
931This list was significantly updated when 2.1c2 was released; the 2.1c1
932release didn't mention most changes that were actually part of 2.1c1:
933
934Legal
935
936- Copyright was assigned to the Python Software Foundation (PSF) and a
937 PSF license (very similar to the CNRI license) was added.
938
939- The CNRI copyright notice was updated to include 2001.
940
941Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000942
Guido van Rossumc9932722001-04-12 02:31:27 +0000943- After a public outcry, assignment to __debug__ is no longer illegal;
944 instead, a warning is issued. It will become illegal in 2.2.
945
Guido van Rossum5b08f132001-04-16 02:05:23 +0000946- Fixed a core dump with "%#x" % 0, and changed the semantics so that
947 "%#x" now always prepends "0x", even if the value is zero.
948
949- Fixed some nits in the bytecode compiler.
950
951- Fixed core dumps when calling certain kinds of non-functions.
952
953- Fixed various core dumps caused by reference count bugs.
954
955Build and Ports
956
957- Use INSTALL_SCRIPT to install script files.
958
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000959- New port: SCO Unixware 7, by Billy G. Allie.
960
Guido van Rossum5b08f132001-04-16 02:05:23 +0000961- Updated RISCOS port.
962
963- Updated BeOS port and notes.
964
965- Various other porting problems resolved.
966
967Library
968
969- The TERMIOS and SOCKET modules are now truly obsolete and
970 unnecessary. Their symbols are incorporated in the termios and
971 socket modules.
972
973- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
974 better tests for pickling.
975
976- threading: make Condition.wait() robust against KeyboardInterrupt.
977
978- zipfile: add support to zipfile to support opening an archive
979 represented by an open file rather than a file name. Fix bug where
980 the archive was not properly closed. Fixed a bug in this bugfix
981 where flush() was called for a read-only file.
982
983- imputil: added an uninstall() method to the ImportManager.
984
985- Canvas: fixed bugs in lower() and tkraise() methods.
986
987- SocketServer: API change (added overridable close_request() method)
988 so that the TCP server can explicitly close the request.
989
990- pstats: Eric Raymond added a simple interactive statistics browser,
991 invoked when the module is run as a script.
992
993- locale: fixed a problem in format().
994
995- webbrowser: made it work when the BROWSER environment variable has a
996 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
997 KDE 2. Fixed some other nits.
998
999- unittest: changes to allow using a different exception than
1000 AssertionError, and added a few more function aliases. Some other
1001 small changes.
1002
1003- urllib, urllib2: fixed redirect problems and a coupleof other nits.
1004
1005- asynchat: fixed a critical bug in asynchat that slipped through the
1006 2.1b2 release. Fixed another rare bug.
1007
1008- Fix some unqualified except: clauses (always a bad code example).
1009
1010XML
1011
1012- pyexpat: new API get_version_string().
1013
1014- Fixed some minidom bugs.
1015
1016Extensions
1017
1018- Fixed a core dump in _weakref. Removed the weakref.mapping()
1019 function (it adds nothing to the API).
1020
1021- Rationalized the use of header files in the readline module, to make
1022 it compile (albeit with some warnings) with the very recent readline
1023 4.2, without breaking for earlier versions.
1024
1025- Hopefully fixed a buffering problem in linuxaudiodev.
1026
1027- Attempted a fix to make the OpenSSL support in the socket module
1028 work again with pre-0.9.5 versions of OpenSSL.
1029
1030Tests
1031
1032- Added a test case for asynchat and asyncore.
1033
1034- Removed coupling between tests where one test failing could break
1035 another.
1036
1037Tools
1038
1039- Ping added an interactive help browser to pydoc, fixed some nits
1040 in the rest of the pydoc code, and added some features to his
1041 inspect module.
1042
1043- An updated python-mode.el version 4.1 which integrates Ken
1044 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1045 much nicer in XEmacs and Emacs. When stepping through your program
1046 with pdb, in either the shell window or the *Python* window, the
1047 source file and line will be tracked by an arrow. Very cool!
1048
1049- IDLE: syntax warnings in interactive mode are changed into errors.
1050
1051- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001052 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001053
1054- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001055
Barry Warsaw11e89c72001-04-11 20:37:57 +00001056
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001057What's New in Python 2.1 beta 2?
1058================================
1059
Guido van Rossum053ae352001-03-22 14:17:21 +00001060(Unlisted are many fixed bugs, more documentation, etc.)
1061
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001062Core language, builtins, and interpreter
1063
Guido van Rossum053ae352001-03-22 14:17:21 +00001064- The nested scopes work (enabled by "from __future__ import
1065 nested_scopes") is completed; in particular, the future now extends
1066 into code executed through exec, eval() and execfile(), and into the
1067 interactive interpreter.
1068
1069- When calling a base class method (e.g. BaseClass.__init__(self)),
1070 this is now allowed even if self is not strictly spoken a class
1071 instance (e.g. when using metaclasses or the Don Beaudry hook).
1072
1073- Slice objects are now comparable but not hashable; this prevents
1074 dict[:] from being accepted but meaningless.
1075
1076- Complex division is now calculated using less braindead algorithms.
1077 This doesn't change semantics except it's more likely to give useful
1078 results in extreme cases. Complex repr() now uses full precision
1079 like float repr().
1080
1081- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1082
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001083- It is illegal to assign to the name __debug__, which is set when the
1084 interpreter starts. It is effectively a compile-time constant.
1085
1086- A warning will be issued if a global statement for a variable
1087 follows a use or assignment of that variable.
1088
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001089Standard library
1090
Guido van Rossum053ae352001-03-22 14:17:21 +00001091- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1092 inspired by JUnit), is now part of the standard library. You now
1093 have a choice of two testing frameworks: unittest requires you to
1094 write testcases as separate code, doctest gathers them from
1095 docstrings. Both approaches have their advantages and
1096 disadvantages.
1097
1098- A new module Tix was added, which wraps the Tix extension library
1099 for Tk. With that module, it is not necessary to statically link
1100 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1101 require" command. See Demo/tix/.
1102
1103- tzparse.py is now obsolete.
1104
1105- In gzip.py, the seek() and tell() methods are removed -- they were
1106 non-functional anyway, and it's better if callers can test for their
1107 existence with hasattr().
1108
1109Python/C API
1110
1111- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1112 that's already in the dictionary during a PyDict_Next() iteration.
1113 This used to fail occasionally when a dictionary resize operation
1114 could be triggered that would rehash all the keys. All other
1115 modifications to the dictionary are still off-limits during a
1116 PyDict_Next() iteration!
1117
1118- New extended APIs related to passing compiler variables around.
1119
1120- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1121 implement isinstance() and issubclass().
1122
1123- Py_BuildValue() now has a "D" conversion to create a Python complex
1124 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001125
Fred Drake4e262a92001-03-22 18:26:47 +00001126- Extensions types which support weak references must now set the
1127 field allocated for the weak reference machinery to NULL themselves;
1128 this is done to avoid the cost of checking each object for having a
1129 weakly referencable type in PyObject_INIT(), since most types are
1130 not weakly referencable.
1131
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001132- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1133 free variables and cell variables to and from the frame's f_locals.
1134
1135- Variants of several functions defined in pythonrun.h have been added
1136 to support the nested_scopes future statement. The variants all end
1137 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1138 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1139 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001140 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001141
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001142Distutils
1143
1144- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1145 into the release tree.
1146
Tim Peters0e57abf2001-05-02 07:39:38 +00001147- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001148 (an uninstaller, more customization of the installer's display)
1149
1150- from Jack Jansen: added Mac-specific code to generate a dialog for
1151 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001152 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001153 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001154
1155- added 'platforms' and 'keywords' to the set of metadata that can be
1156 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001157
1158- applied patches from Jason Tishler to make the compiler class work with
1159 Cygwin.
1160
1161
Tim Peters2fe289a2001-03-01 22:19:38 +00001162What's New in Python 2.1 beta 1?
1163================================
Tim Petersd66595f2001-02-04 03:09:53 +00001164
1165Core language, builtins, and interpreter
1166
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001167- Following an outcry from the community about the amount of code
1168 broken by the nested scopes feature introduced in 2.1a2, we decided
1169 to make this feature optional, and to wait until Python 2.2 (or at
1170 least 6 months) to make it standard. The option can be enabled on a
1171 per-module basis by adding "from __future__ import nested_scopes" at
1172 the beginning of a module (before any other statements, but after
1173 comments and an optional docstring). See PEP 236 (Back to the
1174 __future__) for a description of the __future__ statement. PEP 227
1175 (Statically Nested Scopes) has been updated to reflect this change,
1176 and to clarify the semantics in a number of endcases.
1177
1178- The nested scopes code, when enabled, has been hardened, and most
1179 bugs and memory leaks in it have been fixed.
1180
1181- Compile-time warnings are now generated for a number of conditions
1182 that will break or change in meaning when nested scopes are enabled:
1183
1184 - Using "from...import *" or "exec" without in-clause in a function
1185 scope that also defines a lambda or nested function with one or
1186 more free (non-local) variables. The presence of the import* or
1187 bare exec makes it impossible for the compiler to determine the
1188 exact set of local variables in the outer scope, which makes it
1189 impossible to determine the bindings for free variables in the
1190 inner scope. To avoid the warning about import *, change it into
1191 an import of explicitly name object, or move the import* statement
1192 to the global scope; to avoid the warning about bare exec, use
1193 exec...in... (a good idea anyway -- there's a possibility that
1194 bare exec will be deprecated in the future).
1195
1196 - Use of a global variable in a nested scope with the same name as a
1197 local variable in a surrounding scope. This will change in
1198 meaning with nested scopes: the name in the inner scope will
1199 reference the variable in the outer scope rather than the global
1200 of the same name. To avoid the warning, either rename the outer
1201 variable, or use a global statement in the inner function.
1202
Neil Schemenauera35c6882001-02-27 04:45:05 +00001203- An optional object allocator has been included. This allocator is
1204 optimized for Python objects and should be faster and use less memory
1205 than the standard system allocator. It is not enabled by default
1206 because of possible thread safety problems. The allocator is only
1207 protected by the Python interpreter lock and it is possible that some
1208 extension modules require a thread safe allocator. The object
1209 allocator can be enabled by providing the "--with-pymalloc" option to
1210 configure.
1211
Tim Petersd66595f2001-02-04 03:09:53 +00001212Standard library
1213
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001214- pyexpat now detects the expat version if expat.h defines it. A
1215 number of additional handlers are provided, which are only available
1216 since expat 1.95. In addition, the methods SetParamEntityParsing and
1217 GetInputContext of Parser objects are available with 1.95.x
1218 only. Parser objects now provide the ordered_attributes and
1219 specified_attributes attributes. A new module expat.model was added,
1220 which offers a number of additional constants if 1.95.x is used.
1221
1222- xml.dom offers the new functions registerDOMImplementation and
1223 getDOMImplementation.
1224
1225- xml.dom.minidom offers a toprettyxml method. A number of DOM
1226 conformance issues have been resolved. In particular, Element now
1227 has an hasAttributes method, and the handling of namespaces was
1228 improved.
1229
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001230- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1231 getting information about live Python code, and pydoc.py, a module
1232 for interactively converting docstrings to HTML or text.
1233 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001234 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001235 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1236 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001237
Tim Peters1eff7962001-03-01 02:31:33 +00001238- New library module difflib.py, primarily packaging the SequenceMatcher
1239 class at the heart of the popular ndiff.py file-comparison tool.
1240
1241- doctest.py (a framework for verifying Python code examples in docstrings)
1242 is now part of the std library.
1243
Tim Petersd66595f2001-02-04 03:09:53 +00001244Windows changes
1245
Guido van Rossume3955a82001-03-02 14:05:59 +00001246- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1247 small GUI that lets you browse the module docstrings using your
1248 default web browser.
1249
Tim Peters1eff7962001-03-01 02:31:33 +00001250- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1251 Platforms) is implemented. See
1252
1253 http://python.sourceforge.net/peps/pep-0235.html
1254
1255 for full details, especially the "Current Lower-Left Semantics" section.
1256 The new Windows import rules are simpler than before:
1257
1258 A. If the PYTHONCASEOK environment variable exists, same as
1259 before: silently accept the first case-insensitive match of any
1260 kind; raise ImportError if none found.
1261
1262 B. Else search sys.path for the first case-sensitive match; raise
1263 ImportError if none found.
1264
1265 The same rules have been implented on other platforms with case-
1266 insensitive but case-preserving filesystems too (including Cygwin, and
1267 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001268
Tim Peters25a9ce32001-02-19 07:06:36 +00001269- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1270 what it's supposed to do (and does do under NT and 2000) via direct
1271 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001272 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001273 all Win9x systems before.
1274
Tim Peters1eff7962001-03-01 02:31:33 +00001275- Build: Subproject _test (effectively) renamed to _testcapi.
1276
Tim Peters2fe289a2001-03-01 22:19:38 +00001277New platforms
1278
1279- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1280 Thanks to Steven Majewski!
1281
1282- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1283 Tishler!
1284
Guido van Rossum9089b272001-03-02 06:49:50 +00001285- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1286 Schwertberger! See RISCOS/README for more information -- it seems
1287 that because of the bizarre filename conventions on RISCOS, no port
1288 to that platform is easy. Note that the new variable os.endsep is
1289 silently supported in order to make life easier on this platform,
1290 but we don't advertise it because it's not worth for most folks to
1291 care about RISCOS portability.
1292
Tim Peters25a9ce32001-02-19 07:06:36 +00001293
Tim Petersd7b5e882001-01-25 03:36:26 +00001294What's New in Python 2.1 alpha 2?
1295=================================
Tim Peters40ead762001-01-27 05:35:26 +00001296
Tim Petersd7b5e882001-01-25 03:36:26 +00001297Core language, builtins, and interpreter
1298
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001299- Scopes nest. If a name is used in a function or class, but is not
1300 local, the definition in the nearest enclosing function scope will
1301 be used. One consequence of this change is that lambda statements
1302 could reference variables in the namespaces where the lambda is
1303 defined. In some unusual cases, this change will break code.
1304
1305 In all previous version of Python, names were resolved in exactly
1306 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001307 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001308 function A is defined within a function B, the names bound in B are
1309 not visible in A. The new rules make names bound in B visible in A,
1310 unless A contains a name binding that hides the binding in B.
1311
1312 Section 4.1 of the reference manual describes the new scoping rules
1313 in detail. The test script in Lib/test/test_scope.py demonstrates
1314 some of the effects of the change.
1315
1316 The new rules will cause existing code to break if it defines nested
1317 functions where an outer function has local variables with the same
1318 name as globals or builtins used by the inner function. Example:
1319
1320 def munge(str):
1321 def helper(x):
1322 return str(x)
1323 if type(str) != type(''):
1324 str = helper(str)
1325 return str.strip()
1326
1327 Under the old rules, the name str in helper() is bound to the
1328 builtin function str(). Under the new rules, it will be bound to
1329 the argument named str and an error will occur when helper() is
1330 called.
1331
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001332- The compiler will report a SyntaxError if "from ... import *" occurs
1333 in a function or class scope. The language reference has documented
1334 that this case is illegal, but the compiler never checked for it.
1335 The recent introduction of nested scope makes the meaning of this
1336 form of name binding ambiguous. In a future release, the compiler
1337 may allow this form when there is no possibility of ambiguity.
1338
Tim Peters40ead762001-01-27 05:35:26 +00001339- repr(string) is easier to read, now using hex escapes instead of octal,
1340 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1341
1342 >>> "\texample \r\n" + chr(0) + chr(255)
1343 '\texample \r\n\x00\xff' # in 2.1
1344 '\011example \015\012\000\377' # in 2.0
1345
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001346- Functions are now compared and hashed by identity, not by value, since
1347 the func_code attribute is writable.
1348
Fred Drakefb9d7122001-02-01 20:00:40 +00001349- Weak references (PEP 205) have been added. This involves a few
1350 changes in the core, an extension module (_weakref), and a Python
1351 module (weakref). The weakref module is the public interface. It
1352 includes support for "explicit" weak references, proxy objects, and
1353 mappings with weakly held values.
1354
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001355- A 'continue' statement can now appear in a try block within the body
1356 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001357 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001358
Tim Petersd7b5e882001-01-25 03:36:26 +00001359Standard library
1360
Barry Warsaw30dbd142001-01-31 22:14:01 +00001361- mailbox.py now has a new class, PortableUnixMailbox which is
1362 identical to UnixMailbox but uses a more portable scheme for
1363 determining From_ separators. Also, the constructors for all the
1364 classes in this module have a new optional `factory' argument, which
1365 is a callable used when new message classes must be instantiated by
1366 the next() method.
1367
Tim Petersd7b5e882001-01-25 03:36:26 +00001368- random.py is now self-contained, and offers all the functionality of
1369 the now-deprecated whrandom.py. See the docs for details. random.py
1370 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001371 and restoring the internal state of the generator; and jumpahead(n),
1372 for quickly forcing the internal state to be the same as if n calls to
1373 random() had been made. The latter is particularly useful for multi-
1374 threaded programs, creating one instance of the random.Random() class for
1375 each thread, then using .jumpahead() to force each instance to use a
1376 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001377
Tim Peters0de88fc2001-02-01 04:59:18 +00001378- random.py's seed() function is new. For bit-for-bit compatibility with
1379 prior releases, use the whseed function instead. The new seed function
1380 addresses two problems: (1) The old function couldn't produce more than
1381 about 2**24 distinct internal states; the new one about 2**45 (the best
1382 that can be done in the Wichmann-Hill generator). (2) The old function
1383 sometimes produced identical internal states when passed distinct
1384 integers, and there was no simple way to predict when that would happen;
1385 the new one guarantees to produce distinct internal states for all
1386 arguments in [0, 27814431486576L).
1387
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001388- The socket module now supports raw packets on Linux. The socket
1389 family is AF_PACKET.
1390
Tim Peters9ea17ac2001-02-02 05:57:15 +00001391- test_capi.py is a start at running tests of the Python C API. The tests
1392 are implemented by the new Modules/_testmodule.c.
1393
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001394- A new extension module, _symtable, provides provisional access to the
1395 internal symbol table used by the Python compiler. A higher-level
1396 interface will be added on top of _symtable in a future release.
1397
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001398- Removed the obsolete soundex module.
1399
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001400- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1401 the isSameNode method; NamedNodeMap the get method.
1402
1403- xml.sax.expatreader supports the lexical handler property; it
1404 generates comment, startCDATA, and endCDATA events.
1405
Tim Petersee826f82001-01-31 19:39:44 +00001406Windows changes
1407
1408- Build procedure: the zlib project is built in a different way that
1409 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001410 the zlib binary used. See PCbuild\readme.txt for details. Your old
1411 zlib-related directories can be deleted; you'll need to download fresh
1412 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001413
Tim Peters9ea17ac2001-02-02 05:57:15 +00001414- Build: New subproject _test for the benefit of test_capi.py (see above).
1415
Tim Petersb16c56f2001-02-02 21:24:51 +00001416- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1417 interface to some Python compiler internals).
1418
1419- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001420 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001421
Tim Petersa3a3a032000-11-30 05:22:44 +00001422What's New in Python 2.1 alpha 1?
1423=================================
1424
1425Core language, builtins, and interpreter
1426
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001427- There is a new Unicode companion to the PyObject_Str() API
1428 called PyObject_Unicode(). It behaves in the same way as the
1429 former, but assures that the returned value is an Unicode object
1430 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001431
Guido van Rossumf98eda02001-01-17 15:54:45 +00001432- The comparison operators support "rich comparison overloading" (PEP
1433 207). C extension types can provide a rich comparison function in
1434 the new tp_richcompare slot in the type object. The cmp() function
1435 and the C function PyObject_Compare() first try the new rich
1436 comparison operators before trying the old 3-way comparison. There
1437 is also a new C API PyObject_RichCompare() (which also falls back on
1438 the old 3-way comparison, but does not constrain the outcome of the
1439 rich comparison to a Boolean result).
1440
1441 The rich comparison function takes two objects (at least one of
1442 which is guaranteed to have the type that provided the function) and
1443 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1444 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1445 object, which may be NotImplemented (in which case the tp_compare
1446 slot function is used as a fallback, if defined).
1447
1448 Classes can overload individual comparison operators by defining one
1449 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001450 __ge__. There are no explicit "reflected argument" versions of
1451 these; instead, __lt__ and __gt__ are each other's reflection,
1452 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1453 reflection (similar at the C level). No other implications are
1454 made; in particular, Python does not assume that == is the Boolean
1455 inverse of !=, or that < is the Boolean inverse of >=. This makes
1456 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001457
1458 Classes or types that want to implement (in)equality tests but not
1459 the ordering operators (i.e. unordered types) should implement ==
1460 and !=, and raise an error for the ordering operators.
1461
Guido van Rossuma88479f2001-01-18 14:28:08 +00001462 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001463 Boolean; e.g. a matrix type might want to return a matrix of bits
1464 for A < B, giving elementwise comparisons. Such types should ensure
1465 that any interpretation of their value in a Boolean context raises
1466 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1467 at the C level) to always raise an exception.
1468
Guido van Rossuma88479f2001-01-18 14:28:08 +00001469- Complex numbers use rich comparisons to define == and != but raise
1470 an exception for <, <=, > and >=. Unfortunately, this also means
1471 that cmp() of two complex numbers raises an exception when the two
1472 numbers differ. Since it is not mathematically meaningful to compare
1473 complex numbers except for equality, I hope that this doesn't break
1474 too much code.
1475
Tim Peters3389f192001-02-18 08:48:49 +00001476- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001477 not defined by the language, other than that it's arbitrary but
1478 consistent (see the Reference Manual). An implementation detail changed
1479 in 2.1a1 such that None now compares less than any other object. Code
1480 relying on this new behavior (like code that relied on the previous
1481 behavior) does so at its own risk.
1482
Barry Warsaw573b5412001-01-15 20:43:18 +00001483- Functions and methods now support getting and setting arbitrarily
1484 named attributes (PEP 232). Functions have a new __dict__
1485 (a.k.a. func_dict) which hold the function attributes. Methods get
1486 and set attributes on their underlying im_func. It is a TypeError
1487 to set an attribute on a bound method.
1488
Guido van Rossum051e3352001-01-15 19:11:10 +00001489- The xrange() object implementation has been improved so that
1490 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1491 limitation that in this case len(xrange(sys.maxint)) can't be
1492 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1493 work fine as long as the index i doesn't actually reach 2**31.
1494 (Python uses regular ints for sequence and string indices; fixing
1495 that is much more work.)
1496
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001497- Two changes to from...import:
1498
Guido van Rossumba381232001-02-03 15:06:40 +00001499 1) "from M import X" now works even if (after loading module M)
1500 sys.modules['M'] is not a real module; it's basically a getattr()
1501 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001502
1503 2) "from M import *" now looks for M.__all__ to decide which names to
1504 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1505 filters out names starting with '_' as before. Whether or not
1506 __all__ exists, there's no restriction on the type of M.
1507
Guido van Rossumf61f1662001-01-10 20:13:55 +00001508- File objects have a new method, xreadlines(). This is the fastest
1509 way to iterate over all lines in a file:
1510
1511 for line in file.xreadlines():
1512 ...do something to line...
1513
1514 See the xreadlines module (mentioned below) for how to do this for
1515 other file-like objects.
1516
1517- Even if you don't use file.xreadlines(), you may expect a speedup on
1518 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001519 quite a bit in platform-specific ways: on systems (like Linux) that
1520 support flockfile(), getc_unlocked(), and funlockfile(), those are
1521 used by default. On systems (like Windows) without getc_unlocked(),
1522 a complicated (but still thread-safe) method using fgets() is used by
1523 default.
1524
Tim Petersd52269b2001-01-25 06:23:18 +00001525 You can force use of the fgets() method by #define'ing
1526 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001527 getc_unlocked()).
1528
Tim Petersd52269b2001-01-25 06:23:18 +00001529 You can force fgets() not to be used by #define'ing
1530 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001531 test_bufio.py fails -- and let us know if it does!).
1532
1533- In addition, the fileinput module, while still slower than the other
1534 methods on most platforms, has been sped up too, by using
1535 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001536
1537- Support for run-time warnings has been added, including a new
1538 command line option (-W) to specify the disposition of warnings.
1539 See the description of the warnings module below.
1540
1541- Extensive changes have been made to the coercion code. This mostly
1542 affects extension modules (which can now implement mixed-type
1543 numerical operators without having to use coercion), but
1544 occasionally, in boundary cases the coercion semantics have changed
1545 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001546 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001547 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001548 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001549
Guido van Rossumf98eda02001-01-17 15:54:45 +00001550- In connection with the coercion changes, a new built-in singleton
1551 object, NotImplemented is defined. This can be returned for
1552 operations that wish to indicate they are not implemented for a
1553 particular combination of arguments. From C, this is
1554 Py_NotImplemented.
1555
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001556- The interpreter accepts now bytecode files on the command line even
1557 if they do not have a .pyc or .pyo extension. On Linux, after executing
1558
Martin v. Löwise214baa2001-02-04 22:37:56 +00001559import imp,sys,string
1560magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1561reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1562open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001563
1564 any byte code file can be used as an executable (i.e. as an argument
1565 to execve(2)).
1566
Tim Peters9940b802000-12-01 07:59:35 +00001567- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001568 character. In 1.6 and earlier, they never produced a sign,
1569 and raised an error if the value of the long was too large
1570 to fit in a Python int. In 2.0, they produced a sign if and
1571 only if too large to fit in an int. This was inconsistent
1572 across platforms (because the size of an int varies across
1573 platforms), and inconsistent with hex() and oct(). Example:
1574
1575 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001576 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001577 'ffffffbe' # in 2.0 and before, on 32-bit machines
1578 >>> hex(-0x42L)
1579 '-0x42L' # in all versions of Python
1580
Tim Peters9940b802000-12-01 07:59:35 +00001581 The behavior of %d formats for negative Python longs remains
1582 the same as in 2.0 (although in 1.6 and before, they raised
1583 an error if the long didn't fit in a Python int).
1584
1585 %u formats don't make sense for Python longs, but are allowed
1586 and treated the same as %d in 2.1. In 2.0, a negative long
1587 formatted via %u produced a sign if and only if too large to
1588 fit in an int. In 1.6 and earlier, a negative long formatted
1589 via %u raised an error if it was too big to fit in an int.
1590
Guido van Rossum3661d392000-12-12 22:10:31 +00001591- Dictionary objects have an odd new method, popitem(). This removes
1592 an arbitrary item from the dictionary and returns it (in the form of
1593 a (key, value) pair). This can be useful for algorithms that use a
1594 dictionary as a bag of "to do" items and repeatedly need to pick one
1595 item. Such algorithms normally end up running in quadratic time;
1596 using popitem() they can usually be made to run in linear time.
1597
Tim Peters36cdad12000-12-29 02:06:45 +00001598Standard library
1599
Thomas Woutersfe385252001-01-19 23:16:56 +00001600- In the time module, the time argument to the functions strftime,
1601 localtime, gmtime, asctime and ctime is now optional, defaulting to
1602 the current time (in the local timezone).
1603
Guido van Rossumda91f222001-01-15 16:36:08 +00001604- The ftplib module now defaults to passive mode, which is deemed a
1605 more useful default given that clients are often inside firewalls
1606 these days. Note that this could break if ftplib is used to connect
1607 to a *server* that is inside a firewall, from outside; this is
1608 expected to be a very rare situation. To fix that, you can call
1609 ftp.set_pasv(0).
1610
Martin v. Löwis10a27872001-01-13 09:54:41 +00001611- The module site now treats .pth files not only for path configuration,
1612 but also supports extensions to the initialization code: Lines starting
1613 with import are executed.
1614
Guido van Rossumf61f1662001-01-10 20:13:55 +00001615- There's a new module, warnings, which implements a mechanism for
1616 issuing and filtering warnings. There are some new built-in
1617 exceptions that serve as warning categories, and a new command line
1618 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1619 turns warnings into errors). warnings.warn(message[, category])
1620 issues a warning message; this can also be called from C as
1621 PyErr_Warn(category, message).
1622
1623- A new module xreadlines was added. This exports a single factory
1624 function, xreadlines(). The intention is that this code is the
1625 absolutely fastest way to iterate over all lines in an open
1626 file(-like) object:
1627
1628 import xreadlines
1629 for line in xreadlines.xreadlines(file):
1630 ...do something to line...
1631
1632 This is equivalent to the previous the speed record holder using
1633 file.readlines(sizehint). Note that if file is a real file object
1634 (as opposed to a file-like object), this is equivalent:
1635
1636 for line in file.xreadlines():
1637 ...do something to line...
1638
Tim Peters36cdad12000-12-29 02:06:45 +00001639- The bisect module has new functions bisect_left, insort_left,
1640 bisect_right and insort_right. The old names bisect and insort
1641 are now aliases for bisect_right and insort_right. XXX_right
1642 and XXX_left methods differ in what happens when the new element
1643 compares equal to one or more elements already in the list: the
1644 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001645 right. Code that doesn't care where equal elements end up should
1646 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001647
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001648- The new curses.panel module wraps the panel library that forms part
1649 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1650
Guido van Rossumf61f1662001-01-10 20:13:55 +00001651- The SocketServer module now sets the allow_reuse_address flag by
1652 default in the TCPServer class.
1653
1654- A new function, sys._getframe(), returns the stack frame pointer of
1655 the caller. This is intended only as a building block for
1656 higher-level mechanisms such as string interpolation.
1657
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001658- The pyexpat module supports a number of new handlers, which are
1659 available only in expat 1.2. If invocation of a callback fails, it
1660 will report an additional frame in the traceback. Parser objects
1661 participate now in garbage collection. If expat reports an unknown
1662 encoding, pyexpat will try to use a Python codec; that works only
1663 for single-byte charsets. The parser type objects is exposed as
1664 XMLParserObject.
1665
1666- xml.dom now offers standard definitions for symbolic node type and
1667 exception code constants, and a hierarchy of DOM exceptions. minidom
1668 was adjusted to use them.
1669
1670- The conformance of xml.dom.minidom to the DOM specification was
1671 improved. It detects a number of additional error cases; the
1672 previous/next relationship works even when the tree is modified;
1673 Node supports the normalize() method; NamedNodeMap, DocumentType and
1674 DOMImplementation classes were added; Element supports the
1675 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1676 method.
1677
Guido van Rossumf61f1662001-01-10 20:13:55 +00001678Build issues
1679
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001680- For Unix (and Unix-compatible) builds, configuration and building of
1681 extension modules is now greatly automated. Rather than having to
1682 edit the Modules/Setup file to indicate which modules should be
1683 built and where their include files and libraries are, a
1684 distutils-based setup.py script now takes care of building most
1685 extension modules. All extension modules built this way are built
1686 as shared libraries. Only a few modules that must be linked
1687 statically are still listed in the Setup file; you won't need to
1688 edit their configuration.
1689
1690- Python should now build out of the box on Cygwin. If it doesn't,
1691 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001692
1693- Python now always uses its own (renamed) implementation of getopt()
1694 -- there's too much variation among C library getopt()
1695 implementations.
1696
1697- C++ compilers are better supported; the CXX macro is always set to a
1698 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001699
Tim Petersd92dfe02000-12-12 01:18:41 +00001700Windows changes
1701
1702- select module: By default under Windows, a select() call
1703 can specify no more than 64 sockets. Python now boosts
1704 this Microsoft default to 512. If you need even more than
1705 that, see the MS docs (you'll need to #define FD_SETSIZE
1706 and recompile Python from source).
1707
Guido van Rossumf61f1662001-01-10 20:13:55 +00001708- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1709 subdirectory is no more!
1710
Tim Petersa3a3a032000-11-30 05:22:44 +00001711
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001712What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001713=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001714
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001715Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001716changes are in the file HISTORY. If you are making the jump directly
1717from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1718HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001719
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001720Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1721the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1722http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001723
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001724--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001725
1726======================================================================
1727
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001728What's new in 2.0 (since release candidate 1)?
1729==============================================
1730
1731Standard library
1732
1733- The copy_reg module was modified to clarify its intended use: to
1734 register pickle support for extension types, not for classes.
1735 pickle() will raise a TypeError if it is passed a class.
1736
1737- Fixed a bug in gettext's "normalize and expand" code that prevented
1738 it from finding an existing .mo file.
1739
1740- Restored support for HTTP/0.9 servers in httplib.
1741
Tim Peters989b7b92000-10-16 20:24:53 +00001742- The math module was changed to stop raising OverflowError in case of
1743 underflow, and return 0 instead in underflow cases. Whether Python
1744 used to raise OverflowError in case of underflow was platform-
1745 dependent (it did when the platform math library set errno to ERANGE
1746 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001747
1748- Fixed a bug in StringIO that occurred when the file position was not
1749 at the end of the file and write() was called with enough data to
1750 extend past the end of the file.
1751
1752- Fixed a bug that caused Tkinter error messages to get lost on
1753 Windows. The bug was fixed by replacing direct use of
1754 interp->result with Tcl_GetStringResult(interp).
1755
1756- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1757 redirect response.
1758
1759- Several changes were made to distutils: Some debugging code was
1760 removed from util. Fixed the installer used when an external zip
1761 program (like WinZip) is not found; the source code for this
1762 installer is in Misc/distutils. check_lib() was modified to behave
1763 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1764 test for whether installed modules are on sys.path was changed to
1765 use both normcase() and normpath().
1766
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001767- Several minor bugs were fixed in the xml package (the minidom,
1768 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001769
1770- The regression test driver (regrtest.py) behavior when invoked with
1771 -l changed: It now reports a count of objects that are recognized as
1772 garbage but not freed by the garbage collector.
1773
Tim Peters989b7b92000-10-16 20:24:53 +00001774- The regression test for the math module was changed to test
1775 exceptional behavior when the test is run in verbose mode. Python
1776 cannot yet guarantee consistent exception behavior across platforms,
1777 so the exception part of test_math is run only in verbose mode, and
1778 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001779
1780Internals
1781
1782- PyOS_CheckStack() has been disabled on Win64, where it caused
1783 test_sre to fail.
1784
1785Build issues
1786
1787- Changed compiler flags, so that gcc is always invoked with -Wall and
1788 -Wstrict-prototypes. Users compiling Python with GCC should see
1789 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001790 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001791 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001792
Tim Petersa3a3a032000-11-30 05:22:44 +00001793- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001794
1795Tools and other miscellany
1796
1797- The compiler in Tools/compiler was updated to support the new
1798 language features introduced in 2.0: extended print statement, list
1799 comprehensions, and augmented assignments. The new compiler should
1800 also be backwards compatible with Python 1.5.2; the compiler will
1801 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001802 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001803
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001804What's new in 2.0 release candidate 1 (since beta 2)?
1805=====================================================
1806
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001807What is release candidate 1?
1808
1809We believe that release candidate 1 will fix all known bugs that we
1810intend to fix for the 2.0 final release. This release should be a bit
1811more stable than the previous betas. We would like to see even more
1812widespread testing before the final release, so we are producing this
1813release candidate. The final release will be exactly the same unless
1814any show-stopping (or brown bag) bugs are found by testers of the
1815release candidate.
1816
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001817All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001818to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001819
1820Core language, builtins, and interpreter
1821
1822- A bug that caused crashes when __coerce__ was used with augmented
1823 assignment, e.g. +=, was fixed.
1824
1825- Raise ZeroDivisionError when raising zero to a negative number,
1826 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1827 power operator and the result of math.pow(0.0, -2.0) will vary by
1828 platform. On Linux, it raises a ValueError.
1829
1830- A bug in Unicode string interpolation was fixed that occasionally
1831 caused errors with formats including "%%". For example, the
1832 following expression "%% %s" % u"abc" no longer raises a TypeError.
1833
1834- Compilation of deeply nested expressions raises MemoryError instead
1835 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1836
1837- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1838 rendering them useless. They are now written in binary mode again.
1839
1840Standard library
1841
1842- Keyword arguments are now accepted for most pattern and match object
1843 methods in SRE, the standard regular expression engine.
1844
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001845- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001846 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001847
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001848- Several bugs in the Unicode handling and error handling in _tkinter
1849 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001850
1851- Fix memory management errors in Merge() and Tkapp_Call() routines.
1852
1853- Several changes were made to cStringIO to make it compatible with
1854 the file-like object interface and with StringIO. If operations are
1855 performed on a closed object, an exception is raised. The truncate
1856 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001857 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001858
1859- There were many changes made to the linuxaudiodev module and its
1860 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001861 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001862
1863 Note that this module is named poorly, because it should work
1864 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001865 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001866
1867 The module now raises exceptions when errors occur instead of
1868 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1869 audio) and defines a getptr() method that calls the
1870 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1871
1872- The library_version attribute, introduced in an earlier beta, was
1873 removed because it can not be supported with early versions of the C
1874 readline library, which provides no way to determine the version at
1875 compile-time.
1876
1877- The binascii module is now enabled on Win64.
1878
Tim Peters46446d62000-10-09 21:19:31 +00001879- tokenize.py no longer suffers "recursion depth" errors when parsing
1880 programs with very long string literals.
1881
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001882Internals
1883
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001884- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001885 which is called when the interpreter starts up to determine where
1886 the standard library is installed. These vulnerabilities affect all
1887 previous versions of Python and can be exploited by setting very
1888 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1889 setuid Python script, although use of the wrapper in
1890 Misc/setuid-prog.c will eliminate the vulnerability.
1891
1892- Fixed garbage collection bugs in instance creation that were
1893 triggered when errors occurred during initialization. The solution,
1894 applied in cPickle and in PyInstance_New(), is to call
1895 PyObject_GC_Init() after the initialization of the object's
1896 container attributes is complete.
1897
1898- pyexpat adds definitions of PyModule_AddStringConstant and
1899 PyModule_AddObject if the Python version is less than 2.0, which
1900 provides compatibility with PyXML on Python 1.5.2.
1901
1902- If the platform has a bogus definition for LONG_BIT (the number of
1903 bits in a long), an error will be reported at compile time.
1904
1905- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1906 collection crashes and possibly other, unreported crashes.
1907
1908- Fixed a memory leak in _PyUnicode_Fini().
1909
1910Build issues
1911
1912- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001913 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001914 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001915
1916- The mmap.PAGESIZE constant is now initialized using sysconf when
1917 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1918
1919- The md5 file should now compile on all platforms.
1920
1921- The select module now compiles on platforms that do not define
1922 POLLRDNORM and related constants.
1923
1924- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001925 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001926
Jeremy Hylton10921202000-10-09 18:34:12 +00001927- BeOS: A number of changes were made to the build and installation
1928 process. ar-fake now operates on a directory of object files.
1929 dl_export.h is gone, and its macros now appear on the mwcc command
1930 line during build on PPC BeOS.
1931
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001932- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001933 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001934
1935- Cygwin: Support for shared libraries, Tkinter, and sockets.
1936
1937- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1938
1939Tools and other miscellany
1940
1941- Removed debugging prints from main used with freeze.
1942
Tim Peters46446d62000-10-09 21:19:31 +00001943- IDLE auto-indent no longer crashes when it encounters Unicode
1944 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001945
1946What's new in 2.0 beta 2 (since beta 1)?
1947========================================
1948
1949Core language, builtins, and interpreter
1950
Tim Peters482c0212000-09-26 06:33:09 +00001951- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001952 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001953
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001954- Add -h and -V command line options to print the usage message and
1955 Python version number and exit immediately.
1956
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001957- eval() and exec accept Unicode objects as code parameters.
1958
1959- getattr() and setattr() now also accept Unicode objects for the
1960 attribute name, which are converted to strings using the default
1961 encoding before lookup.
1962
1963- Multiplication on string and Unicode now does proper bounds
1964 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1965 string is too long."
1966
1967- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001968 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001969
Jeremy Hylton1b618592000-09-26 05:32:36 +00001970
1971Standard library and extensions
1972
Guido van Rossum5b08f132001-04-16 02:05:23 +00001973- socket module: the OpenSSL code now adds support for RAND_status()
1974 and EGD (Entropy Gathering Device).
1975
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001976- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001977 argument checking; it still takes no arguments.
1978
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001979- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001980
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001981- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001982
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001983- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001984
1985- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001986 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001987
1988- copy: Copy Unicode objects atomically.
1989
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001990- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001991
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001992- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001993
Fred Drake67233bc2000-09-26 16:40:27 +00001994- dbm: Add get() and setdefault() methods to dbm object. Add constant
1995 `library' to module that names the library used. Added doc strings
1996 and method names to error messages. Uses configure to determine
1997 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
1998 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001999
2000- distutils: Update to version 0.9.3.
2001
2002- dl: Add several dl.RTLD_ constants.
2003
2004- fpectl: Now supported on FreeBSD.
2005
2006- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
2007 found by the collector will be saved in gc.garbage. This is useful
2008 for debugging a program that creates reference cycles.
2009
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002010- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00002011 of HTTP class. Do not close socket on zero-length response. Do not
2012 crash when server sends invalid content-length header.
2013
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002014- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002015
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002016- marshal: When reading a short, sign-extend on platforms where shorts
2017 are bigger than 16 bits. When reading a long, repair the unportable
2018 sign extension that was being done for 64-bit machines. (It assumed
2019 that signed right shift sign-extends.)
2020
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002021- operator: Add contains(), invert(), __invert__() as aliases for
2022 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002023
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002024- os: Add support for popen2() and popen3() on all platforms where
2025 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002026
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002027- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002028 clicking on a file in Explorer (or passing the file name to the
2029 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002030
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002031- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002032 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002033
2034- pickle: Now raises ValueError when an invalid pickle that contains
2035 a non-string repr where a string repr was expected. This behavior
2036 matches cPickle.
2037
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002038- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002039
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002040- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002041
2042- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002043 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002044 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002045
2046- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002047 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002048
2049- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002050 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002051 few cycles during startup since the first call to
2052 setdefaultencoding() will initialize the codec registry and the
2053 encodings package.
2054
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002055- socket: Support for size hint in readlines() method of object returned
2056 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002057
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002058- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002059 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002060 is followed by whitespace.
2061
Tim Petersa3a3a032000-11-30 05:22:44 +00002062- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002063
2064- struct: Check ranges for bytes and shorts.
2065
2066- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002067 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002068
2069- Tkinter: Image objects are now guaranteed to have unique ids. Set
2070 event.delta to zero if Tk version doesn't support mousewheel.
2071 Removed some debugging prints.
2072
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002073- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002074
Fred Drake67233bc2000-09-26 16:40:27 +00002075- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002076 which works around a bug in Norton AntiVirus 2000 that leads directly
2077 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002078
2079- xml: New version detection code allows PyXML to override standard
2080 XML package if PyXML version is greater than 0.6.1.
2081
Fred Drake64bb3802000-09-26 16:21:35 +00002082- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2083 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2084 tree only for nodes which are sufficiently interesting to a specific
2085 application. Does not provide the HTML-specific extensions. Still
2086 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002087
Fred Drake64bb3802000-09-26 16:21:35 +00002088- xml.sax: SAX 2 support for Python, including all the handler
2089 interfaces needed to process XML 1.0 compliant XML. Some
2090 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002091
Fred Drake64bb3802000-09-26 16:21:35 +00002092- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2093 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002094
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002095
Jeremy Hylton1b618592000-09-26 05:32:36 +00002096C API
2097
2098- Add three new convenience functions for module initialization --
2099 PyModule_AddObject(), PyModule_AddIntConstant(), and
2100 PyModule_AddStringConstant().
2101
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002102- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002103 removed and add #error to Python.h if NULL isn't defined after
2104 #include of stdio.h.
2105
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002106- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002107 backwards compatibility (at the source level) with old extensions.
2108
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002109- A wrapper API was added for signal() and sigaction(). Instead of
2110 either function, always use PyOS_getsig() to get a signal handler
2111 and PyOS_setsig() to set one. A new convenience typedef
2112 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002113
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002114- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002115 internal data buffer and size of a string object -- or the default
2116 encoded version of a Unicode object.
2117
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002118- PyString_Size() and PyString_AsString() accept Unicode objects.
2119
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002120- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002121 exists). INT_MAX and LONG_MAX will always be defined, even if
2122 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002123
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002124- PyFloat_FromString takes a second argument, pend, that was
2125 effectively useless. It is now officially useless but preserved for
2126 backwards compatibility. If the pend argument is not NULL, *pend is
2127 set to NULL.
2128
2129- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2130 for the attribute name. See note on getattr() above.
2131
2132- A few bug fixes to argument processing for Unicode.
2133 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2134 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2135 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002136 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002137
2138- Py_BuildValue accepts B format (for bgen-generated code).
2139
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002140
Jeremy Hylton1b618592000-09-26 05:32:36 +00002141Internals
2142
2143- On Unix, fix code for finding Python installation directory so that
2144 it works when argv[0] is a relative path.
2145
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002146- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002147 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002148 rather than by generating a copy of the object.
2149
Tim Peters482c0212000-09-26 06:33:09 +00002150- Several of the internal Unicode tables are much smaller now, and
2151 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002152
Jeremy Hylton97693b02000-09-26 17:42:51 +00002153- In the garbage collector: Fixed bug in collection of tuples. Fixed
2154 bug that caused some instances to be removed from the container set
2155 while they were still live. Fixed parsing in gc.set_debug() for
2156 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002157
2158- Fixed refcount problem in instance deallocation that only occurred
2159 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2160
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002161- On Windows, getpythonregpath is now protected against null data in
2162 registry key.
2163
2164- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002165 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002166
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002167
Jeremy Hylton1b618592000-09-26 05:32:36 +00002168Build and platform-specific issues
2169
2170- Better support of GNU Pth via --with-pth configure option.
2171
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002172- Python/C API now properly exposed to dynamically-loaded extension
2173 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002174
2175- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2176 Don't define MS_SYNC to be zero when it is undefined. Added missing
2177 prototypes in posixmodule.c.
2178
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002179- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002180 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002181
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002182- Fix largefile support on older NetBSD systems and OpenBSD by adding
2183 define for TELL64.
2184
2185
2186Tools and other miscellany
2187
2188- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2189
2190- freeze: The modulefinder now works with 2.0 opcodes.
2191
Tim Petersa3a3a032000-11-30 05:22:44 +00002192- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002193 Move hackery of sys.argv until after the Tk instance has been
2194 created, which allows the application-specific Tkinter
2195 initialization to be executed if present; also pass an explicit
2196 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002197
Jeremy Hylton1b618592000-09-26 05:32:36 +00002198
2199What's new in 2.0 beta 1?
2200=========================
2201
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002202Source Incompatibilities
2203------------------------
2204
2205None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2206such as single-argument append(), connect() and bind(), and changes to
2207str(long) and repr(float).
2208
2209
2210Binary Incompatibilities
2211------------------------
2212
2213- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2214with Python 2.0; these extensions will have to be rebuilt for Python
22152.0.
2216
2217- On Windows, attempting to import a third party extension built for
2218Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2219can do about this. Check your PYTHONPATH environment variable!
2220
2221- Python bytecode files (*.pyc and *.pyo) are not compatible between
2222releases.
2223
2224
2225Overview of Changes Since 1.6
2226-----------------------------
2227
2228There are many new modules (including brand new XML support through
2229the xml package, and i18n support through the gettext module); a list
2230of all new modules is included below. Lots of bugs have been fixed.
2231
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002232The process for making major new changes to the language has changed
2233since Python 1.6. Enhancements must now be documented by a Python
2234Enhancement Proposal (PEP) before they can be accepted.
2235
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002236There are several important syntax enhancements, described in more
2237detail below:
2238
2239 - Augmented assignment, e.g. x += 1
2240
2241 - List comprehensions, e.g. [x**2 for x in range(10)]
2242
2243 - Extended import statement, e.g. import Module as Name
2244
2245 - Extended print statement, e.g. print >> file, "Hello"
2246
2247Other important changes:
2248
2249 - Optional collection of cyclical garbage
2250
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002251Python Enhancement Proposal (PEP)
2252---------------------------------
2253
2254PEP stands for Python Enhancement Proposal. A PEP is a design
2255document providing information to the Python community, or describing
2256a new feature for Python. The PEP should provide a concise technical
2257specification of the feature and a rationale for the feature.
2258
2259We intend PEPs to be the primary mechanisms for proposing new
2260features, for collecting community input on an issue, and for
2261documenting the design decisions that have gone into Python. The PEP
2262author is responsible for building consensus within the community and
2263documenting dissenting opinions.
2264
2265The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002266
2267Augmented Assignment
2268--------------------
2269
2270This must have been the most-requested feature of the past years!
2271Eleven new assignment operators were added:
2272
Guido van Rossume905e952000-09-05 12:42:46 +00002273 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002274
2275For example,
2276
2277 A += B
2278
2279is similar to
2280
2281 A = A + B
2282
2283except that A is evaluated only once (relevant when A is something
2284like dict[index].attr).
2285
2286However, if A is a mutable object, A may be modified in place. Thus,
2287if A is a number or a string, A += B has the same effect as A = A+B
2288(except A is only evaluated once); but if a is a list, A += B has the
2289same effect as A.extend(B)!
2290
2291Classes and built-in object types can override the new operators in
2292order to implement the in-place behavior; the not-in-place behavior is
2293used automatically as a fallback when an object doesn't implement the
2294in-place behavior. For classes, the method name is derived from the
2295method name for the corresponding not-in-place operator by inserting
2296an 'i' in front of the name, e.g. __iadd__ implements in-place
2297__add__.
2298
2299Augmented assignment was implemented by Thomas Wouters.
2300
2301
2302List Comprehensions
2303-------------------
2304
2305This is a flexible new notation for lists whose elements are computed
2306from another list (or lists). The simplest form is:
2307
2308 [<expression> for <variable> in <sequence>]
2309
Guido van Rossum56db0952000-09-06 23:34:25 +00002310For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002311This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002312
2313You can also add a condition:
2314
2315 [<expression> for <variable> in <sequence> if <condition>]
2316
2317For example, [w for w in words if w == w.lower()] would yield the list
2318of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002319than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002320
2321You can also have nested for loops and more than one 'if' clause. For
2322example, here's a function that flattens a sequence of sequences::
2323
2324 def flatten(seq):
2325 return [x for subseq in seq for x in subseq]
2326
2327 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2328
2329This prints
2330
2331 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2332
2333List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002334Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002335
2336
2337Extended Import Statement
2338-------------------------
2339
2340Many people have asked for a way to import a module under a different
2341name. This can be accomplished like this:
2342
2343 import foo
2344 bar = foo
2345 del foo
2346
2347but this common idiom gets old quickly. A simple extension of the
2348import statement now allows this to be written as follows:
2349
2350 import foo as bar
2351
2352There's also a variant for 'from ... import':
2353
2354 from foo import bar as spam
2355
2356This also works with packages; e.g. you can write this:
2357
2358 import test.regrtest as regrtest
2359
2360Note that 'as' is not a new keyword -- it is recognized only in this
2361context (this is only possible because the syntax for the import
2362statement doesn't involve expressions).
2363
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002364Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002365
2366
2367Extended Print Statement
2368------------------------
2369
2370Easily the most controversial new feature, this extension to the print
2371statement adds an option to make the output go to a different file
2372than the default sys.stdout.
2373
2374For example, to write an error message to sys.stderr, you can now
2375write:
2376
2377 print >> sys.stderr, "Error: bad dog!"
2378
2379As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002380evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002381
2382 print >> None, "Hello world"
2383
2384is equivalent to
2385
2386 print "Hello world"
2387
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002388Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002389
2390
2391Optional Collection of Cyclical Garbage
2392---------------------------------------
2393
2394Python is now equipped with a garbage collector that can hunt down
2395cyclical references between Python objects. It's no replacement for
2396reference counting; in fact, it depends on the reference counts being
2397correct, and decides that a set of objects belong to a cycle if all
2398their reference counts can be accounted for from their references to
2399each other. This devious scheme was first proposed by Eric Tiedemann,
2400and brought to implementation by Neil Schemenauer.
2401
2402There's a module "gc" that lets you control some parameters of the
2403garbage collection. There's also an option to the configure script
2404that lets you enable or disable the garbage collection. In 2.0b1,
2405it's on by default, so that we (hopefully) can collect decent user
2406experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002407performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002408off by default in the final 2.0 release.
2409
2410
2411Smaller Changes
2412---------------
2413
2414A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2415map(None, seq1, seq2, ...) when the sequences have the same length;
2416i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2417the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002418zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002419
2420sys.version_info is a tuple (major, minor, micro, level, serial).
2421
2422Dictionaries have an odd new method, setdefault(key, default).
2423dict.setdefault(key, default) returns dict[key] if it exists; if not,
2424it sets dict[key] to default and returns that value. Thus:
2425
2426 dict.setdefault(key, []).append(item)
2427
2428does the same work as this common idiom:
2429
2430 if not dict.has_key(key):
2431 dict[key] = []
2432 dict[key].append(item)
2433
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002434There are two new variants of SyntaxError that are raised for
2435indentation-related errors: IndentationError and TabError.
2436
2437Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2438escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002439
2440The limits on the size of expressions and file in Python source code
2441have been raised from 2**16 to 2**32. Previous versions of Python
2442were limited because the maximum argument size the Python VM accepted
2443was 2**16. This limited the size of object constructor expressions,
2444e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2445limit was raised thanks to a patch by Charles Waldman that effectively
2446fixes the problem. It is now much more likely that you will be
2447limited by available memory than by an arbitrary limit in Python.
2448
2449The interpreter's maximum recursion depth can be modified by Python
2450programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2451limit is the maximum number of recursive calls that can be made by
2452Python code. The limit exists to prevent infinite recursion from
2453overflowing the C stack and causing a core dump. The default value is
24541000. The maximum safe value for a particular platform can be found
2455by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002456
2457New Modules and Packages
2458------------------------
2459
2460atexit - for registering functions to be called when Python exits.
2461
2462imputil - Greg Stein's alternative API for writing custom import
2463hooks.
2464
2465pyexpat - an interface to the Expat XML parser, contributed by Paul
2466Prescod.
2467
2468xml - a new package with XML support code organized (so far) in three
2469subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2470would fill a volume. There's a special feature whereby a
2471user-installed package named _xmlplus overrides the standard
2472xmlpackage; this is intended to give the XML SIG a hook to distribute
2473backwards-compatible updates to the standard xml package.
2474
2475webbrowser - a platform-independent API to launch a web browser.
2476
2477
Guido van Rossume905e952000-09-05 12:42:46 +00002478Changed Modules
2479---------------
2480
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002481array -- new methods for array objects: count, extend, index, pop, and
2482remove
2483
2484binascii -- new functions b2a_hex and a2b_hex that convert between
2485binary data and its hex representation
2486
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002487calendar -- Many new functions that support features including control
2488over which day of the week is the first day, returning strings instead
2489of printing them. Also new symbolic constants for days of week,
2490e.g. MONDAY, ..., SUNDAY.
2491
2492cgi -- FieldStorage objects have a getvalue method that works like a
2493dictionary's get method and returns the value attribute of the object.
2494
2495ConfigParser -- The parser object has new methods has_option,
2496remove_section, remove_option, set, and write. They allow the module
2497to be used for writing config files as well as reading them.
2498
2499ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002500optionally support the RFC 959 REST command.
2501
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002502gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002503
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002504httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2505the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002506
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002507locale -- implement getdefaultlocale for Win32 and Macintosh
2508
2509marshal -- no longer dumps core when marshaling deeply nested or
2510recursive data structures
2511
2512os -- new functions isatty, seteuid, setegid, setreuid, setregid
2513
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002514os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2515support under Unix.
2516
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002517os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002518
2519os.path -- fix semantics of os.path.commonprefix
2520
2521smtplib -- support for sending very long messages
2522
2523socket -- new function getfqdn()
2524
2525readline -- new functions to read, write and truncate history files.
2526The readline section of the library reference manual contains an
2527example.
2528
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002529select -- add interface to poll system call
2530
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002531shutil -- new copyfileobj function
2532
2533SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2534HTTP server.
2535
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002536Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002537
2538urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002539e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002540
2541whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002542
2543
2544Obsolete Modules
2545----------------
2546
2547None. However note that 1.6 made a whole slew of modules obsolete:
2548stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2549poly, zmod, strop, util, whatsound.
2550
2551
2552Changed, New, Obsolete Tools
2553----------------------------
2554
Tim Peters8b092332000-09-05 20:15:25 +00002555None.
Guido van Rossume905e952000-09-05 12:42:46 +00002556
2557
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002558C-level Changes
2559---------------
2560
2561Several cleanup jobs were carried out throughout the source code.
2562
2563All C code was converted to ANSI C; we got rid of all uses of the
2564Py_PROTO() macro, which makes the header files a lot more readable.
2565
2566Most of the portability hacks were moved to a new header file,
2567pyport.h; several other new header files were added and some old
2568header files were removed, in an attempt to create a more rational set
2569of header files. (Few of these ever need to be included explicitly;
2570they are all included by Python.h.)
2571
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002572Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002573and Win64, especially for the new Intel Itanium processor. Mick also
2574added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002575
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002576The C APIs to return an object's size have been update to consistently
2577use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2578previous versions, the abstract interfaces used PyXXX_Length and the
2579concrete interfaces used PyXXX_Size. The old names,
2580e.g. PyObject_Length, are still available for backwards compatibility
2581at the API level, but are deprecated.
2582
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002583The PyOS_CheckStack function has been implemented on Windows by
2584Fredrik Lundh. It prevents Python from failing with a stack overflow
2585on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002586
2587The GC changes resulted in creation of two new slots on object,
2588tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002589the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002590
2591The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002592C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002593
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002594PyErr_Format has been updated to automatically calculate the size of
2595the buffer needed to hold the formatted result string. This change
2596prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002597
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002598New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002599
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002600PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2601that are the same as their non-Ex counterparts except they take an
2602extra flag argument that tells them to close the file when done.
2603
2604XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002605
Tim Peters8b092332000-09-05 20:15:25 +00002606
2607Windows Changes
2608---------------
2609
2610New popen2/popen3/peopen4 in os module (see Changed Modules above).
2611
2612os.popen is much more usable on Windows 95 and 98. See Microsoft
2613Knowledge Base article Q150956. The Win9x workaround described there
2614is implemented by the new w9xpopen.exe helper in the root of your
2615Python installation. Note that Python uses this internally; it is not
2616a standalone program.
2617
2618Administrator privileges are no longer required to install Python
2619on Windows NT or Windows 2000. If you have administrator privileges,
2620Python's registry info will be written under HKEY_LOCAL_MACHINE.
2621Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002622under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002623uses of Python, but will prevent some advanced uses from working
2624(for example, running a Python script as an NT service, or possibly
2625from CGI).
2626
2627[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2628installer; instead, it installs the needed Tcl/Tk files directly in the
2629Python directory. If you already have a Tcl/Tk installation, this
2630wastes some disk space (about 4 Megs) but avoids problems with
2631conflicting Tcl/Tk installations, and makes it much easier for Python
2632to ensure that Tcl/Tk can find all its files.
2633
2634[This was new in 1.6] The Windows installer now installs by default in
2635\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2636
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002637
2638Updates to the changes between 1.5.2 and 1.6
2639--------------------------------------------
2640
2641The 1.6 NEWS file can't be changed after the release is done, so here
2642is some late-breaking news:
2643
2644New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2645and changes to getlocale() and setlocale().
2646
2647The new module is now enabled per default.
2648
2649It is not true that the encodings codecs cannot be used for normal
2650strings: the string.encode() (which is also present on 8-bit strings
2651!) allows using them for 8-bit strings too, e.g. to convert files from
2652cp1252 (Windows) to latin-1 or vice-versa.
2653
2654Japanese codecs are available from Tamito KAJIYAMA:
2655http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2656
2657
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002658======================================================================