blob: 0e312c17c8e9d894c44c2428e82397e19cc662de [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
Martin v. Löwis16dc7f42001-09-30 20:32:11 +000041- quopri's encode and decode methods take an optional header parameter,
42 which indicates whether output is intended for the header 'Q' encoding.
43
Guido van Rossumed554f62001-10-02 23:15:37 +000044Tools/Demos
45
46- Demo/dns was removed. It no longer serves any purpose; a package
47 derived from it is now maintained by Anthony Baxter, see
48 http://PyDNS.SourceForge.net.
Tim Petersabf925f2001-09-28 21:53:42 +000049
50Build
51
52C API
53
Tim Petersd38b1c72001-09-30 05:09:37 +000054- PyLong_AsLongLong() now accepts int (as well as long) arguments.
55 Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
56 as long) arguments.
57
Tim Petersabf925f2001-09-28 21:53:42 +000058New platforms
59
60Tests
61
62Windows
63
Tim Peters1ce3cf72001-10-01 17:58:40 +000064- The signal module now supports SIGBREAK on Windows, thanks to Steven
65 Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
66 action remains to call Win32 ExitProcess(). This can be changed via
67 signal.signal(). For example:
68
69 # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
70 # (SIGINT) behavior.
71 import signal
72 signal.signal(signal.SIGBREAK,
73 signal.default_int_handler)
74
75 try:
76 while 1:
77 pass
78 except KeyboardInterrupt:
79 # We get here on Ctrl+C or Ctrl+Break now; if we had not changed
80 # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
81 # program without the possibility for any Python-level cleanup).
82 print "Clean exit"
83
Tim Petersabf925f2001-09-28 21:53:42 +000084
Tim Petersb07352e2001-09-08 01:25:47 +000085What's New in Python 2.2a4?
Barry Warsaw86fbaf82001-09-28 15:26:12 +000086Release date: 28-Sep-2001
Tim Petersb07352e2001-09-08 01:25:47 +000087===========================
88
Guido van Rossum808eea72001-09-25 04:15:41 +000089Type/class unification and new-style classes
90
91- pydoc and inspect are now aware of new-style classes;
92 e.g. help(list) at the interactive prompt now shows proper
93 documentation for all operations on list objects.
94
95- Applications using Jim Fulton's ExtensionClass module can now safely
96 be used with Python 2.2. In particular, Zope 2.4.1 now works with
97 Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
98 examples also work again. It is hoped that Gtk and Boost also work
99 with 2.2a4 and beyond. (If you can confirm this, please write
100 webmaster@python.org; if there are still problems, please open a bug
101 report on SourceForge.)
Tim Petersb07352e2001-09-08 01:25:47 +0000102
Tim Peters66c1a522001-09-24 21:17:50 +0000103- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
104 These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__'
105 in the constructed property object. fget, fset and fdel weren't
106 discoverable from Python in 2.2a3. __doc__ is new, and allows to
107 associate a docstring with a property.
108
Guido van Rossum808eea72001-09-25 04:15:41 +0000109- Comparison overloading is now more completely implemented. For
110 example, a str subclass instance can properly be compared to a str
111 instance, and it can properly overload comparison. Ditto for most
112 other built-in object types.
113
114- The repr() of new-style classes has changed; instead of <type
115 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
116 *except* for built-in types, which are still rendered as <type
117 'Foo'> (to avoid upsetting existing code that might parse or
118 otherwise rely on repr() of certain type objects).
119
120- The repr() of new-style objects is now always <Foo object at XXX>;
121 previously, it was sometimes <Foo instance at XXX>.
122
123- For new-style classes, what was previously called __getattr__ is now
124 called __getattribute__. This method, if defined, is called for
125 *every* attribute access. A new __getattr__ hook mor similar to the
126 one in classic classes is defined which is called only if regular
127 attribute access raises AttributeError; to catch *all* attribute
128 access, you can use __getattribute__ (for new-style classes). If
129 both are defined, __getattribute__ is called first, and if it raises
130 AttributeError, __getattr__ is called.
131
132- The __class__ attribute of new-style objects can be assigned to.
133 The new class must have the same C-level object layout as the old
134 class.
135
136- The builtin file type can be subclassed now. In the usual pattern,
137 "file" is the name of the builtin type, and file() is a new builtin
138 constructor, with the same signature as the builtin open() function.
139 file() is now the preferred way to open a file.
140
141- Previously, __new__ would only see sequential arguments passed to
142 the type in a constructor call; __init__ would see both sequential
143 and keyword arguments. This made no sense whatsoever any more, so
144 now both __new__ and __init__ see all arguments.
145
146- Previously, hash() applied to an instance of a subclass of str or
147 unicode always returned 0. This has been repaired.
148
149- Previously, an operation on an instance of a subclass of an
150 immutable type (int, long, float, complex, tuple, str, unicode),
151 where the subtype didn't override the operation (and so the
152 operation was handled by the builtin type), could return that
153 instance instead a value of the base type. For example, if s was of
154 a str sublass type, s[:] returned s as-is. Now it returns a str
155 with the same value as s.
156
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000157- Provisional support for pickling new-style objects has been added.
158
Guido van Rossum808eea72001-09-25 04:15:41 +0000159Core
160
Tim Peters2c9aa5e2001-09-23 04:06:05 +0000161- file.writelines() now accepts any iterable object producing strings.
162
Marc-André Lemburgaefd7662001-09-20 12:59:37 +0000163- PyUnicode_FromEncodedObject() now works very much like
164 PyObject_Str(obj) in that it tries to use __str__/tp_str
165 on the object if the object is not a string or buffer. This
166 makes unicode() behave like str() when applied to non-string/buffer
167 objects.
168
Martin v. Löwis2777c022001-09-19 13:47:32 +0000169- PyFile_WriteObject now passes Unicode object to the file's write
170 method. As a result, all file-like object which may be the target
171 of a print statement must support Unicode objects, i.e. they must
172 at least convert them into ASCII strings.
173
Guido van Rossum624c8af2001-09-18 15:21:04 +0000174- Thread scheduling on Solaris should be improved; it is no longer
175 necessary to insert a small sleep at the start of a thread in order
176 to let other runnable threads be scheduled.
177
Tim Petersb07352e2001-09-08 01:25:47 +0000178Library
179
Marc-André Lemburgbf990172001-09-27 14:17:33 +0000180- StringIO.StringIO instances and cStringIO.StringIO instances support
181 read character buffer compatible objects for their .write() methods.
182 These objects are converted to strings and then handled as such
183 by the instances.
184
Barry Warsaw2f600732001-09-24 04:28:10 +0000185- The "email" package has been added. This is basically a port of the
186 mimelib package <http://sf.net/projects/mimelib> with API changes
187 and some implementations updated to use iterators and generators.
188
Tim Peters8a9c2842001-09-22 21:30:22 +0000189- difflib.ndiff() and difflib.Differ.compare() are generators now. This
190 restores the ability of Tools/scripts/ndiff.py to start producing output
191 before the entire comparison is complete.
192
Barry Warsaw58b072d2001-09-22 04:44:21 +0000193- StringIO.StringIO instances and cStringIO.StringIO instances support
194 iteration just like file objects (i.e. their .readline() method is
195 called for each iteration until it returns an empty string).
196
Marc-André Lemburg494f2ae2001-09-19 11:33:31 +0000197- The codecs module has grown four new helper APIs to access
198 builtin codecs: getencoder(), getdecoder(), getreader(),
199 getwriter().
200
Guido van Rossum624c8af2001-09-18 15:21:04 +0000201- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
202 simplifies writing XML RPC servers.
203
Barry Warsaw647d5e82001-09-28 17:01:02 +0000204- os.path.realpath(): a new function that returns the absolute pathname
Guido van Rossum624c8af2001-09-18 15:21:04 +0000205 after interpretation of symbolic links. On non-Unix systems, this
206 is an alias for os.path.abspath().
207
Tim Peters16a77ad2001-09-08 04:00:12 +0000208- operator.indexOf() (PySequence_Index() in the C API) now works with any
209 iterable object.
210
Guido van Rossum624c8af2001-09-18 15:21:04 +0000211- smtplib now supports various authentication and security features of
212 the SMTP protocol through the new login() and starttls() methods.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000213
Guido van Rossum624c8af2001-09-18 15:21:04 +0000214- hmac: a new module implementing keyed hashing for message
215 authentication.
216
217- mimetypes now recognizes more extensions and file types. At the
218 same time, some mappings not sanctioned by IANA were removed.
Guido van Rossumd8185ca2001-09-14 16:35:16 +0000219
Guido van Rossum624c8af2001-09-18 15:21:04 +0000220- The "compiler" package has been brought up to date to the state of
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000221 Python 2.2 bytecode generation. It has also been promoted from a
222 Tool to a standard library package. (Tools/compiler still exists as
223 a sample driver.)
224
Guido van Rossumc9ed5dc2001-09-20 05:30:24 +0000225Tools
Guido van Rossum624c8af2001-09-18 15:21:04 +0000226
Tim Petersb07352e2001-09-08 01:25:47 +0000227Build
228
Guido van Rossum624c8af2001-09-18 15:21:04 +0000229- Large file support (LFS) is now automatic when the platform supports
230 it; no more manual configuration tweaks are needed. On Linux, at
231 least, it's possible to have a system whose C library supports large
232 files but whose kernel doesn't; in this case, large file support is
233 still enabled but doesn't do you any good unless you upgrade your
234 kernel or share your Python executable with another system whose
235 kernel has large file support.
236
237- The configure script now supplies plausible defaults in a
238 cross-compilation environment. This doesn't mean that the supplied
239 values are always correct, or that cross-compilation now works
240 flawlessly -- but it's a first step (and it shuts up most of
241 autoconf's warnings about AC_TRY_RUN).
242
243- The Unix build is now a bit less chatty, courtesy of the parser
244 generator. The build is completely silent (except for errors) when
245 using "make -s", thanks to a -q option to setup.py.
246
Tim Petersb07352e2001-09-08 01:25:47 +0000247C API
248
Guido van Rossum624c8af2001-09-18 15:21:04 +0000249- The "structmember" API now supports some new flag bits to deny read
250 and/or write access to attributes in restricted execution mode.
251
Tim Petersb07352e2001-09-08 01:25:47 +0000252New platforms
253
Guido van Rossum624c8af2001-09-18 15:21:04 +0000254- Compaq's iPAQ handheld, running the "familiar" Linux distribution
255 (http://familiar.handhelds.org).
256
Tim Petersb07352e2001-09-08 01:25:47 +0000257Tests
258
Tim Peters8a9c2842001-09-22 21:30:22 +0000259- The "classic" standard tests, which work by comparing stdout to
260 an expected-output file under Lib/test/output/, no longer stop at
261 the first mismatch. Instead the test is run to completion, and a
262 variant of ndiff-style comparison is used to report all differences.
263 This is much easier to understand than the previous style of reporting.
264
265- The unittest-based standard tests now use regrtest's test_main()
266 convention, instead of running as a side-effect of merely being
267 imported. This allows these tests to be run in more natural and
268 flexible ways as unittests, outside the regrtest framework.
269
270- regrtest.py is much better integrated with unittest and doctest now,
271 especially in regard to reporting errors.
272
Tim Petersb07352e2001-09-08 01:25:47 +0000273Windows
274
Guido van Rossum624c8af2001-09-18 15:21:04 +0000275- Large file support now also works for files > 4GB, on filesystems
Tim Peters8a9c2842001-09-22 21:30:22 +0000276 that support it (NTFS under Windows 2000). See "What's New in
277 Python 2.2a3" for more detail.
Guido van Rossum624c8af2001-09-18 15:21:04 +0000278
Tim Petersb07352e2001-09-08 01:25:47 +0000279
Tim Petersedc99312001-08-22 21:36:50 +0000280What's New in Python 2.2a3?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000281Release Date: 07-Sep-2001
Tim Petersedc99312001-08-22 21:36:50 +0000282===========================
283
284Core
285
Tim Peters9fffa3e2001-09-04 05:14:19 +0000286- Conversion of long to float now raises OverflowError if the long is too
287 big to represent as a C double.
288
Tim Peters32f453e2001-09-03 08:35:41 +0000289- The 3-argument builtin pow() no longer allows a third non-None argument
290 if either of the first two arguments is a float, or if both are of
291 integer types and the second argument is negative (in which latter case
292 the arguments are converted to float, so this is really the same
293 restriction).
294
Tim Peters5d2b77c2001-09-03 05:47:38 +0000295- The builtin dir() now returns more information, and sometimes much
296 more, generally naming all attributes of an object, and all attributes
297 reachable from the object via its class, and from its class's base
298 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
299 an empty list. In 2.2a3,
300
301 >>> dir([])
302 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
303 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
304 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
305 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
306 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
307 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
308 'reverse', 'sort']
309
310 dir(module) continues to return only the module's attributes, though.
311
Tim Petersbdee63f2001-09-02 03:40:59 +0000312- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +0000313 than raising OverflowError. This is a partial implementation of PEP
314 237. You can use -Wdefault::OverflowWarning to enable a warning for
315 this situation, and -Werror::OverflowWarning to revert to the old
316 OverflowError exception.
317
Guido van Rossum61c345f2001-09-04 03:26:15 +0000318- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +0000319 warnings for the use of classic division. (See PEP 238.) Possible
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000320 values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
321 -Qold, meaning the / operator has its classic meaning and no
322 warnings are issued. Using -Qwarn issues a run-time warning about
323 all uses of classic division for int and long arguments; -Qwarnall
324 also warns about classic division for float and complex arguments
325 (for use with fixdiv.py). Using -Qnew is questionable; it turns on
326 new division by default, but only in the __main__ module. You can
327 usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the
328 __main__ module new division, and warns about classic division
329 everywhere else.
Guido van Rossumae457142001-08-31 18:31:35 +0000330
Tim Petersbdee63f2001-09-02 03:40:59 +0000331- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +0000332 long, float, str, unicode, and tuple. (The types complex, list and
333 dictionary can also be subclassed; this was introduced earlier.)
334 Note that restrictions apply when subclassing immutable built-in
335 types: you can only affect the value of the instance by overloading
336 __new__. You can add mutable attributes, and the subclass instances
337 will have a __dict__ attribute, but you cannot change the "value"
338 (as implemented by the base class) of an immutable subclass instance
339 once it is created.
340
Guido van Rossumaaf80c82001-09-02 13:44:35 +0000341- The dictionary constructor now takes an optional argument, a
342 mapping-like object, and initializes the dictionary from its
343 (key, value) pairs.
344
Tim Petersbdee63f2001-09-02 03:40:59 +0000345- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +0000346 "cooperative super calls" in a multiple inheritance setting. For an
347 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
348
Guido van Rossum8d7234d2001-09-06 22:02:58 +0000349- A new built-in type, property, has been added. This enables the
350 creation of "properties". These are attributes implemented by
351 getter and setter functions (or only one of these for read-only or
352 write-only attributes), without the need to override __getattr__.
353 See http://www.python.org/2.2/descrintro.html#property
Guido van Rossumae457142001-08-31 18:31:35 +0000354
Tim Petersbdee63f2001-09-02 03:40:59 +0000355- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +0000356 liberalized, to allow leading zeroes. Examples of literals now
357 legal that were SyntaxErrors before:
358
359 00.0 0e3 0100j 07.5 00000000000000000008.
360
Tim Petersbdee63f2001-09-02 03:40:59 +0000361- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +0000362 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
363
Tim Petersedc99312001-08-22 21:36:50 +0000364Library
365
Martin v. Löwiscb227c92001-09-06 08:54:16 +0000366- telnetlib includes symbolic names for the options, and support for
367 setting an option negotiation callback.
368
Tim Petersa40c7932001-09-05 22:36:56 +0000369- The new C standard no longer requires that math libraries set errno to
370 ERANGE on overflow. For platform libraries that exploit this new
371 freedom, Python's overflow-checking was wholly broken. A new overflow-
372 checking scheme attempts to repair that, but may not be reliable on all
373 platforms (C doesn't seem to provide anything both useful and portable
374 in this area anymore).
375
Martin v. Löwis44f86962001-09-05 13:44:54 +0000376- Asynchronous timeout actions are available through the new class
377 threading.Timer.
378
Tim Peters78526162001-09-05 00:53:45 +0000379- math.log and math.log10 now return sensible results for even huge
380 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
381
Tim Petersbdee63f2001-09-02 03:40:59 +0000382- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000383 currently held. See the docs for the imp module.
384
Tim Petersbdee63f2001-09-02 03:40:59 +0000385- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000386 dumps containing ints written on platforms where Python ints are 8 bytes.
387 When read on a box where Python ints are 4 bytes, such values are
388 converted to Python longs.
389
Tim Petersbdee63f2001-09-02 03:40:59 +0000390- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000391 code objects is no longer allowed. This plugs a security hole.
392
Steve Purcell6091cd62001-09-06 16:05:17 +0000393- unittest.TestResult instances no longer store references to tracebacks
394 generated by test failures. This prevents unexpected dangling references
395 to objects that should be garbage collected between tests.
396
Tim Petersedc99312001-08-22 21:36:50 +0000397Tools
398
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000399- Tools/scripts/fixdiv.py has been added which can be used to fix
400 division operators as per PEP 238.
401
Tim Petersedc99312001-08-22 21:36:50 +0000402Build
403
Barry Warsawd6c8ca62001-09-07 18:13:44 +0000404- If you are an adventurous person using Mac OS X you may want to look at
405 Mac/OSX. There is a Makefile there that will build Python as a real Mac
406 application, which can be used for experimenting with Carbon or Cocoa.
407 Discussion of this on pythonmac-sig, please.
408
Tim Peters7eea37e2001-09-04 22:08:56 +0000409C API
410
411- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000412
Tim Peters9fffa3e2001-09-04 05:14:19 +0000413- Note that PyLong_AsDouble can fail! This has always been true, but no
414 callers checked for it. It's more likely to fail now, because overflow
415 errors are properly detected now. The proper way to check:
416
417 double x = PyLong_AsDouble(some_long_object);
418 if (x == -1.0 && PyErr_Occurred()) {
419 /* The conversion failed. */
420 }
421
Tim Petersbdee63f2001-09-02 03:40:59 +0000422- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000423 compile but will not participate in GC. To upgrade an extension
424 module:
425
426 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000427
Neil Schemenauer4042c692001-08-30 15:38:01 +0000428 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
429 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000430
Neil Schemenauer4042c692001-08-30 15:38:01 +0000431 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
432 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000433
Neil Schemenauer4042c692001-08-30 15:38:01 +0000434 - remove PyGC_HEAD_SIZE from object size calculations
435
436 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
437
Tim Petersbdee63f2001-09-02 03:40:59 +0000438- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000439 These can be used safely to construct string objects from a
440 sprintf-style format string (similar to the format string supported
441 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000442
Tim Petersedc99312001-08-22 21:36:50 +0000443New platforms
444
Tim Petersb7da0902001-09-02 23:01:43 +0000445- Stephen Hansen contributed patches sufficient to get a clean compile
446 under Borland C (Windows), but he reports problems running it and ran
447 out of time to complete the port. Volunteers? Expect a MemoryError
448 when importing the types module; this is probably shallow, and
449 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000450
Tim Petersedc99312001-08-22 21:36:50 +0000451Tests
452
453Windows
454
Tim Peters6e13a562001-09-06 00:32:15 +0000455- Large file support is now enabled on Win32 platforms as well as on
456 Win64. This means that, for example, you can use f.tell() and f.seek()
457 to manipulate files larger than 2 gigabytes (provided you have enough
458 disk space, and are using a Windows filesystem that supports large
Tim Peters9a9471c2001-09-11 23:18:51 +0000459 partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
460 filesize limit, and large file support makes no difference there.
461 FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
462 NTFS has no practical limit on file size, and files of any size can be
463 used from Python now.
Tim Peters6e13a562001-09-06 00:32:15 +0000464
Tim Petersbdee63f2001-09-02 03:40:59 +0000465- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000466 points to command.com (patch from Brian Quinlan).
467
Tim Petersedc99312001-08-22 21:36:50 +0000468
Tim Peters20f51a72001-07-21 02:31:40 +0000469What's New in Python 2.2a2?
Barry Warsaw86fbaf82001-09-28 15:26:12 +0000470Release Date: 22-Aug-2001
Tim Peters20f51a72001-07-21 02:31:40 +0000471===========================
472
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000473Build
474
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000475- Tim Peters developed a brand new Windows installer using Wise 8.1,
476 generously donated to us by Wise Solutions.
477
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000478- configure supports a new option --enable-unicode, with the values
479 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
480 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000481
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000482- A new configure option --enable-framework builds a Mac OS X framework,
483 which "make frameworkinstall" will install. This provides a starting
484 point for more mac-like functionality, join pythonmac-sig@python.org
485 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000486
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000487- The NeXT platform is no longer supported.
488
489- The `new' module is now statically linked.
490
Tim Peters0afb6092001-08-15 06:06:44 +0000491Tools
492
493- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000494 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000495 the module docstring for details.
496
Tim Peters20f51a72001-07-21 02:31:40 +0000497Tests
498
Tim Peters5e824c32001-08-12 22:25:01 +0000499- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000500 platforms, allowing to give clearer test result output. regrtest
501 also has optional --use/-u switch to run normally disabled tests
502 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000503
Tim Peters20f51a72001-07-21 02:31:40 +0000504- Several new tests in the standard test suite, with special thanks to
505 Nick Mathewson.
506
507Core
508
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000509- The floor division operator // has been added as outlined in PEP
510 238. The / operator still provides classic division (and will until
511 Python 3.0) unless "from __future__ import division" is included, in
512 which case the / operator will provide true division. The operator
513 module provides truediv() and floordiv() functions. Augmented
514 assignment variants are included, as are the equivalent overloadable
515 methods and C API methods. See the PEP for a full discussion:
516 <http://python.sf.net/peps/pep-0238.html>
517
Tim Peters6cd6a822001-08-17 22:11:27 +0000518- Future statements are now effective in simulated interactive shells
519 (like IDLE). This should "just work" by magic, but read Michael
520 Hudson's "Future statements in simulated shells" PEP 264 for full
521 details: <http://python.sf.net/peps/pep-0264.html>.
522
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000523- The type/class unification (PEP 252-253) was integrated into the
524 trunk and is not so tentative any more (the exact specification of
525 some features is still tentative). A lot of work has done on fixing
526 bugs and adding robustness and features (performance still has to
527 come a long way).
528
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000529- Warnings about a mismatch in the Python API during extension import
530 now use the Python warning framework (which makes it possible to
531 write filters for these warnings).
532
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000533- A function's __dict__ (aka func_dict) will now always be a
534 dictionary. It used to be possible to delete it or set it to None,
535 but now both actions raise TypeErrors. It is still legal to set it
536 to a dictionary object. Getting func.__dict__ before any attributes
537 have been assigned now returns an empty dictionary instead of None.
538
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000539- A new command line option, -E, was added which disables the use of
540 all environment variables, or at least those that are specifically
541 significant to Python. Usually those have a name starting with
542 "PYTHON". This was used to fix a problem where the tests fail if
543 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
544 older distribution.
545
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000546Library
547
Tim Peters5e824c32001-08-12 22:25:01 +0000548- New class Differ and new functions ndiff() and restore() in difflib.py.
549 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000550 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000551
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000552- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
553 value using the minimal quoting required for the value; more
554 reliable than using xml.sax.saxutils.escape() for attribute values.
555
556- Readline completion support for cmd.Cmd was added.
557
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000558- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
559
560- Added function threading.BoundedSemaphore()
561
562- Added Ka-Ping Yee's cgitb.py module.
563
564- The `new' module now exposes the CO_xxx flags.
565
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000566New platforms
567
568C API
569
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000570- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
571 which provide a cross-platform implementations for the
572 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
573 the standard sprintf() and vsprintf() C lib APIs, these versions
574 apply bounds checking on the used buffer which enhances protection
575 against buffer overruns.
576
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000577- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000578 and extensions using different Unicode widths is rendered next to
579 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000580 will result in an ImportError. Unicode extensions writers must make
581 sure to check the Unicode width compatibility in their extensions by
582 using at least one of the mangled Unicode APIs in the extension.
583
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000584- Two new flags METH_NOARGS and METH_O are available in method definition
585 tables to simplify implementation of methods with no arguments and a
586 single untyped argument. Calling such methods is more efficient than
587 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
588 deprecated.
589
Tim Petersc1731372001-08-04 08:12:36 +0000590Windows
591
592- "import module" now compiles module.pyw if it exists and nothing else
593 relevant is found.
594
Tim Peters20f51a72001-07-21 02:31:40 +0000595
Guido van Rossum55a78992001-07-17 17:22:32 +0000596What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +0000597===========================
598
599Core
Tim Petersa814db52001-05-14 07:05:58 +0000600
Tim Peters6d6c1a32001-08-02 04:15:00 +0000601- TENTATIVELY, a large amount of code implementing much of what's
602 described in PEP 252 (Making Types Look More Like Classes) and PEP
603 253 (Subtyping Built-in Types) was added. This will be released
604 with Python 2.2a1. Documentation will be provided separately
605 through http://www.python.org/2.2/. The purpose of releasing this
606 with Python 2.2a1 is to test backwards compatibility. It is
607 possible, though not likely, that a decision is made not to release
608 this code as part of 2.2 final, if any serious backwards
609 incompapatibilities are found during alpha testing that cannot be
610 repaired.
611
Guido van Rossum55a78992001-07-17 17:22:32 +0000612- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000613 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000614 more 'yield' statements. See PEP 255. Since this adds a new
615 keyword to the language, this feature must be enabled by including a
616 future statement: "from __future__ import generators" (see PEP 236).
617 Generators will become a standard feature in a future release
618 (probably 2.3). Without this future statement, 'yield' remains an
619 ordinary identifier, but a warning is issued each time it is used.
620 (These warnings currently don't conform to the warnings framework of
621 PEP 230; we intend to fix this in 2.2a2.)
622
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000623- The UTF-16 codec was modified to be more RFC compliant. It will now
624 only remove BOM characters at the start of the string and then
625 only if running in native mode (UTF-16-LE and -BE won't remove a
626 leading BMO character).
627
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000628- Strings now have a new method .decode() to complement the already
629 existing .encode() method. These two methods provide direct access
630 to the corresponding decoders and encoders of the registered codecs.
631
632 To enhance the usability of the .encode() method, the special
633 casing of Unicode object return values was dropped (Unicode objects
634 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000635
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000636 Both methods will now return whatever the codec in charge of the
637 requested encoding returns as object, e.g. Unicode codecs will
638 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
639 will return u"äöü"). This enables codec writer to create codecs
640 for various simple to use conversions.
641
642 New codecs were added to demonstrate these new features (the .encode()
643 and .decode() columns indicate the type of the returned objects):
644
645 Name | .encode() | .decode() | Description
646 ----------------------------------------------------------------------
647 uu | string | string | UU codec (e.g. for email)
648 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000649 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000650 zlib | string | string | zlib compression
651 hex | string | string | 2-byte hex codec
652 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
653
Mark Hammond2a0af792001-05-14 03:09:36 +0000654- Some operating systems now support the concept of a default Unicode
655 encoding for file system operations. Notably, Windows supports 'mbcs'
656 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000657 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000658 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000659
660 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000661 functions that return filenames (such as os.listdir()) to return Python
662 string objects pre-encoded using the default file system encoding for
663 the platform. As this encoding is likely to be different from Python's
664 default encoding, converting this name to a Unicode object before passing
665 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000666 would attempt to use its default encoding (generally ASCII) rather than
667 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000668
Tim Petersa814db52001-05-14 07:05:58 +0000669 In general, this change simply removes surprises when working with
670 Unicode and the file system, making these operations work as you expect,
671 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000672 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000673
Tim Peters61dff2b2001-05-08 15:43:37 +0000674- Float (and complex) literals in source code were evaluated to full
675 precision only when running from a .py file; the same code loaded from a
676 .pyc (or .pyo) file could suffer numeric differences starting at about the
677 12th significant decimal digit. For example, on a machine with IEEE-754
678 floating arithmetic,
679
680 x = 9007199254740992.0
681 print long(x)
682
683 printed 9007199254740992 if run directly from .py, but 9007199254740000
684 if from a compiled (.pyc or .pyo) file. This was due to marshal using
685 str(float) instead of repr(float) when building code objects. marshal
686 now uses repr(float) instead, which should reproduce floats to full
687 machine precision (assuming the platform C float<->string I/O conversion
688 functions are of good quality).
689
690 This may cause floating-point results to change in some cases, and
691 usually for the better, but may also cause numerically unstable
692 algorithms to break.
693
Tim Peters2f228e72001-05-13 00:19:31 +0000694- The implementation of dicts suffers fewer collisions, which has speed
695 benefits. However, the order in which dict entries appear in dict.keys(),
696 dict.values() and dict.items() may differ from previous releases for a
697 given dict. Nothing is defined about this order, so no program should
698 rely on it. Nevertheless, it's easy to write test cases that rely on the
699 order by accident, typically because of printing the str() or repr() of a
700 dict to an "expected results" file. See Lib/test/test_support.py's new
701 sortdict(dict) function for a simple way to display a dict in sorted
702 order.
703
Tim Peters7a3bfc32001-06-12 01:22:22 +0000704- Many other small changes to dicts were made, resulting in faster
705 operation along the most common code paths.
706
Guido van Rossum10315822001-05-01 20:54:30 +0000707- Dictionary objects now support the "in" operator: "x in dict" means
708 the same as dict.has_key(x).
709
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000710- The update() method of dictionaries now accepts generic mapping
711 objects. Specifically the argument object must support the .keys()
712 and __getitem__() methods. This allows you to say, for example,
713 {}.update(UserDict())
714
Guido van Rossum10315822001-05-01 20:54:30 +0000715- Iterators were added; this is a generalized way of providing values
716 to a for loop. See PEP 234. There's a new built-in function iter()
717 to return an iterator. There's a new protocol to get the next value
718 from an iterator using the next() method (in Python) or the
719 tp_iternext slot (in C). There's a new protocol to get iterators
720 using the __iter__() method (in Python) or the tp_iter slot (in C).
721 Iterating (i.e. a for loop) over a dictionary generates its keys.
722 Iterating over a file generates its lines.
723
Tim Petersf553f892001-05-01 20:45:31 +0000724- The following functions were generalized to work nicely with iterator
725 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000726 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000727 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
728 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000729 join() method of strings
730 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000731 'x in y' and 'x not in y' (PySequence_Contains() in C API)
732 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000733 right-hand side of assignment statements with multiple targets, such as
734 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000735
Tim Petersd85e1022001-05-11 21:51:48 +0000736- Accessing module attributes is significantly faster (for example,
737 random.random or os.path or yourPythonModule.yourAttribute).
738
Tim Peterse63415e2001-05-08 04:38:29 +0000739- Comparing dictionary objects via == and != is faster, and now works even
740 if the keys and values don't support comparisons other than ==.
741
Tim Peters95bf9392001-05-10 08:32:44 +0000742- Comparing dictionaries in ways other than == and != is slower: there were
743 insecurities in the dict comparison implementation that could cause Python
744 to crash if the element comparison routines for the dict keys and/or
745 values mutated the dicts. Making the code bulletproof slowed it down.
746
Tim Peterseb28ef22001-06-02 05:27:19 +0000747- Collisions in dicts are resolved via a new approach, which can help
748 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000749 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000750 faster now. Thanks to Christian Tismer for pointing out the cause and
751 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000752
Tim Peters52e155e2001-06-16 05:42:57 +0000753- repr() is much faster for large containers (dict, list, tuple).
754
755
Tim Petersa814db52001-05-14 07:05:58 +0000756Library
757
Fred Drake960fdf92001-07-20 18:38:26 +0000758- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
759 were added to the string module. These a locale-indenpendent
760 constants, unlike letters, lowercase, and uppercase. These are now
761 use in appropriate locations in the standard library.
762
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000763- The flags used in dlopen calls can now be configured using
764 sys.setdlopenflags and queried using sys.getdlopenflags.
765
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000766- Fredrik Lundh's xmlrpclib is now a standard library module. This
767 provides full client-side XML-RPC support. In addition,
768 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
769 one asyncore-based). Thanks to Eric Raymond for the documentation.
770
Guido van Rossum643d3912001-07-05 14:46:25 +0000771- The xrange() object is simplified: it no longer supports slicing,
772 repetition, comparisons, efficient 'in' checking, the tolist()
773 method, or the start, stop and step attributes. See PEP 260.
774
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000775- A new function fnmatch.filter to filter lists of file names was added.
776
Barry Warsawffd674d2001-05-22 16:00:10 +0000777- calendar.py uses month and day names based on the current locale.
778
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000779- strop is now *really* obsolete (this was announced before with 1.6),
780 and issues DeprecationWarning when used (except for the four items
781 that are still imported into string.py).
782
Tim Petersa814db52001-05-14 07:05:58 +0000783- Cookie.py now sorts key+value pairs by key in output strings.
784
785- pprint.isrecursive(object) didn't correctly identify recursive objects.
786 Now it does.
787
Tim Peters95b3f782001-05-14 18:39:41 +0000788- pprint functions now much faster for large containers (tuple, list, dict).
789
Tim Peters7b9542a2001-06-10 23:40:19 +0000790- New 'q' and 'Q' format codes in the struct module, corresponding to C
791 types "long long" and "unsigned long long" (on Windows, __int64). In
792 native mode, these can be used only when the platform C compiler supports
793 these types (when HAVE_LONG_LONG is #define'd by the Python config
794 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000795 In standard mode, 'q' and 'Q' are supported on all platforms, and are
796 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000797
Guido van Rossum83213cc2001-06-12 16:48:52 +0000798- The site module installs a new built-in function 'help' that invokes
799 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
800 it displays a message reminding the user to use 'help()' or
801 'help(object)'.
802
Tim Petersa814db52001-05-14 07:05:58 +0000803Tests
804
805- New test_mutants.py runs dict comparisons where the key and value
806 comparison operators mutute the dicts randomly during comparison. This
807 rapidly causes Python to crash under earlier releases (not for the faint
808 of heart: it can also cause Win9x to freeze or reboot!).
809
810- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000811 pprint.isreadable() return sensible results. Also verifies that simple
812 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000813
Tim Peters4324aa32001-05-28 22:30:08 +0000814C API
815
816- Removed the unused last_is_sticky argument from the internal
817 _PyTuple_Resize(). If this affects you, you were cheating.
818
819
Guido van Rossum55a78992001-07-17 17:22:32 +0000820======================================================================
821
822
Guido van Rossumffe13be2001-04-16 18:46:45 +0000823What's New in Python 2.1 (final)?
824=================================
825
826We only changed a few things since the last release candidate, all in
827Python library code:
828
829- A bug in the locale module was fixed that affected locales which
830 define no grouping for numeric formatting.
831
832- A few bugs in the weakref module's implementations of weak
833 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
834 and the test suite was updated to check for these bugs.
835
836- An old bug in the os.path.walk() function (introduced in Python
837 2.0!) was fixed: a non-existent file would cause an exception
838 instead of being ignored.
839
840- Fixed a few bugs in the new symtable module found by Neil Norwitz's
841 PyChecker.
842
843
Guido van Rossum5b08f132001-04-16 02:05:23 +0000844What's New in Python 2.1c2?
845===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000846
Guido van Rossum5b08f132001-04-16 02:05:23 +0000847A flurry of small changes, and one showstopper fixed in the nick of
848time made it necessary to release another release candidate. The list
849here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000850
Guido van Rossum5b08f132001-04-16 02:05:23 +0000851Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000852
Guido van Rossum5b08f132001-04-16 02:05:23 +0000853- Tim discovered a nasty bug in the dictionary code, caused by
854 PyDict_Next() calling dict_resize(), and the GC code's use of
855 PyDict_Next() violating an assumption in dict_items(). This was
856 fixed with considerable amounts of band-aid, but the net effect is a
857 saner and more robust implementation.
858
859- Made a bunch of symbols static that were accidentally global.
860
861Build and Ports
862
863- The setup.py script didn't check for a new enough version of zlib
864 (1.1.3 is needed). Now it does.
865
866- Changed "make clean" target to also remove shared libraries.
867
868- Added a more general warning about the SGI Irix optimizer to README.
869
870Library
871
872- Fix a bug in urllib.basejoin("http://host", "../file.html") which
873 omitted the slash between host and file.html.
874
875- The mailbox module's _Mailbox class contained a completely broken
876 and undocumented seek() method. Ripped it out.
877
878- Fixed a bunch of typos in various library modules (urllib2, smtpd,
879 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
880
881- Fixed a few last-minute bugs in unittest.
882
883Extensions
884
885- Reverted the patch to the OpenSSL code in socketmodule.c to support
886 RAND_status() and the EGD, and the subsequent patch that tried to
887 fix it for pre-0.9.5 versions; the problem with the patch is that on
888 some systems it issues a warning whenever socket is imported, and
889 that's unacceptable.
890
891Tests
892
893- Fixed the pickle tests to work with "import test.test_pickle".
894
895- Tweaked test_locale.py to actually run the test Windows.
896
897- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
898 not "wb" (which is not a valid mode at all).
899
900- Fix pstats browser crashes. Import readline if it exists to make
901 the user interface nicer.
902
903- Add "import thread" to the top of test modules that import the
904 threading module (test_asynchat and test_threadedtempfile). This
905 prevents test failures caused by a broken threading module resulting
906 from a previously caught failed import.
907
908- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
909 needed on some platforms (e.g. Solaris 8) when the tests are run
910 twice in succession.
911
912- Skip rather than fail test_sunaudiodev if no audio device is found.
913
914
915What's New in Python 2.1c1?
916===========================
917
918This list was significantly updated when 2.1c2 was released; the 2.1c1
919release didn't mention most changes that were actually part of 2.1c1:
920
921Legal
922
923- Copyright was assigned to the Python Software Foundation (PSF) and a
924 PSF license (very similar to the CNRI license) was added.
925
926- The CNRI copyright notice was updated to include 2001.
927
928Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000929
Guido van Rossumc9932722001-04-12 02:31:27 +0000930- After a public outcry, assignment to __debug__ is no longer illegal;
931 instead, a warning is issued. It will become illegal in 2.2.
932
Guido van Rossum5b08f132001-04-16 02:05:23 +0000933- Fixed a core dump with "%#x" % 0, and changed the semantics so that
934 "%#x" now always prepends "0x", even if the value is zero.
935
936- Fixed some nits in the bytecode compiler.
937
938- Fixed core dumps when calling certain kinds of non-functions.
939
940- Fixed various core dumps caused by reference count bugs.
941
942Build and Ports
943
944- Use INSTALL_SCRIPT to install script files.
945
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000946- New port: SCO Unixware 7, by Billy G. Allie.
947
Guido van Rossum5b08f132001-04-16 02:05:23 +0000948- Updated RISCOS port.
949
950- Updated BeOS port and notes.
951
952- Various other porting problems resolved.
953
954Library
955
956- The TERMIOS and SOCKET modules are now truly obsolete and
957 unnecessary. Their symbols are incorporated in the termios and
958 socket modules.
959
960- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
961 better tests for pickling.
962
963- threading: make Condition.wait() robust against KeyboardInterrupt.
964
965- zipfile: add support to zipfile to support opening an archive
966 represented by an open file rather than a file name. Fix bug where
967 the archive was not properly closed. Fixed a bug in this bugfix
968 where flush() was called for a read-only file.
969
970- imputil: added an uninstall() method to the ImportManager.
971
972- Canvas: fixed bugs in lower() and tkraise() methods.
973
974- SocketServer: API change (added overridable close_request() method)
975 so that the TCP server can explicitly close the request.
976
977- pstats: Eric Raymond added a simple interactive statistics browser,
978 invoked when the module is run as a script.
979
980- locale: fixed a problem in format().
981
982- webbrowser: made it work when the BROWSER environment variable has a
983 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
984 KDE 2. Fixed some other nits.
985
986- unittest: changes to allow using a different exception than
987 AssertionError, and added a few more function aliases. Some other
988 small changes.
989
990- urllib, urllib2: fixed redirect problems and a coupleof other nits.
991
992- asynchat: fixed a critical bug in asynchat that slipped through the
993 2.1b2 release. Fixed another rare bug.
994
995- Fix some unqualified except: clauses (always a bad code example).
996
997XML
998
999- pyexpat: new API get_version_string().
1000
1001- Fixed some minidom bugs.
1002
1003Extensions
1004
1005- Fixed a core dump in _weakref. Removed the weakref.mapping()
1006 function (it adds nothing to the API).
1007
1008- Rationalized the use of header files in the readline module, to make
1009 it compile (albeit with some warnings) with the very recent readline
1010 4.2, without breaking for earlier versions.
1011
1012- Hopefully fixed a buffering problem in linuxaudiodev.
1013
1014- Attempted a fix to make the OpenSSL support in the socket module
1015 work again with pre-0.9.5 versions of OpenSSL.
1016
1017Tests
1018
1019- Added a test case for asynchat and asyncore.
1020
1021- Removed coupling between tests where one test failing could break
1022 another.
1023
1024Tools
1025
1026- Ping added an interactive help browser to pydoc, fixed some nits
1027 in the rest of the pydoc code, and added some features to his
1028 inspect module.
1029
1030- An updated python-mode.el version 4.1 which integrates Ken
1031 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
1032 much nicer in XEmacs and Emacs. When stepping through your program
1033 with pdb, in either the shell window or the *Python* window, the
1034 source file and line will be tracked by an arrow. Very cool!
1035
1036- IDLE: syntax warnings in interactive mode are changed into errors.
1037
1038- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +00001039 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +00001040
1041- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +00001042
Barry Warsaw11e89c72001-04-11 20:37:57 +00001043
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001044What's New in Python 2.1 beta 2?
1045================================
1046
Guido van Rossum053ae352001-03-22 14:17:21 +00001047(Unlisted are many fixed bugs, more documentation, etc.)
1048
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001049Core language, builtins, and interpreter
1050
Guido van Rossum053ae352001-03-22 14:17:21 +00001051- The nested scopes work (enabled by "from __future__ import
1052 nested_scopes") is completed; in particular, the future now extends
1053 into code executed through exec, eval() and execfile(), and into the
1054 interactive interpreter.
1055
1056- When calling a base class method (e.g. BaseClass.__init__(self)),
1057 this is now allowed even if self is not strictly spoken a class
1058 instance (e.g. when using metaclasses or the Don Beaudry hook).
1059
1060- Slice objects are now comparable but not hashable; this prevents
1061 dict[:] from being accepted but meaningless.
1062
1063- Complex division is now calculated using less braindead algorithms.
1064 This doesn't change semantics except it's more likely to give useful
1065 results in extreme cases. Complex repr() now uses full precision
1066 like float repr().
1067
1068- sgmllib.py now calls handle_decl() for simple <!...> declarations.
1069
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001070- It is illegal to assign to the name __debug__, which is set when the
1071 interpreter starts. It is effectively a compile-time constant.
1072
1073- A warning will be issued if a global statement for a variable
1074 follows a use or assignment of that variable.
1075
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001076Standard library
1077
Guido van Rossum053ae352001-03-22 14:17:21 +00001078- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
1079 inspired by JUnit), is now part of the standard library. You now
1080 have a choice of two testing frameworks: unittest requires you to
1081 write testcases as separate code, doctest gathers them from
1082 docstrings. Both approaches have their advantages and
1083 disadvantages.
1084
1085- A new module Tix was added, which wraps the Tix extension library
1086 for Tk. With that module, it is not necessary to statically link
1087 Tix with _tkinter, since Tix will be loaded with Tcl's "package
1088 require" command. See Demo/tix/.
1089
1090- tzparse.py is now obsolete.
1091
1092- In gzip.py, the seek() and tell() methods are removed -- they were
1093 non-functional anyway, and it's better if callers can test for their
1094 existence with hasattr().
1095
1096Python/C API
1097
1098- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
1099 that's already in the dictionary during a PyDict_Next() iteration.
1100 This used to fail occasionally when a dictionary resize operation
1101 could be triggered that would rehash all the keys. All other
1102 modifications to the dictionary are still off-limits during a
1103 PyDict_Next() iteration!
1104
1105- New extended APIs related to passing compiler variables around.
1106
1107- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
1108 implement isinstance() and issubclass().
1109
1110- Py_BuildValue() now has a "D" conversion to create a Python complex
1111 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001112
Fred Drake4e262a92001-03-22 18:26:47 +00001113- Extensions types which support weak references must now set the
1114 field allocated for the weak reference machinery to NULL themselves;
1115 this is done to avoid the cost of checking each object for having a
1116 weakly referencable type in PyObject_INIT(), since most types are
1117 not weakly referencable.
1118
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001119- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
1120 free variables and cell variables to and from the frame's f_locals.
1121
1122- Variants of several functions defined in pythonrun.h have been added
1123 to support the nested_scopes future statement. The variants all end
1124 in Flags and take an extra argument, a PyCompilerFlags *; examples:
1125 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
1126 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +00001127 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +00001128
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001129Distutils
1130
1131- the sdist command now writes a PKG-INFO file, as described in PEP 241,
1132 into the release tree.
1133
Tim Peters0e57abf2001-05-02 07:39:38 +00001134- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001135 (an uninstaller, more customization of the installer's display)
1136
1137- from Jack Jansen: added Mac-specific code to generate a dialog for
1138 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +00001139 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001140 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +00001141
1142- added 'platforms' and 'keywords' to the set of metadata that can be
1143 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +00001144
1145- applied patches from Jason Tishler to make the compiler class work with
1146 Cygwin.
1147
1148
Tim Peters2fe289a2001-03-01 22:19:38 +00001149What's New in Python 2.1 beta 1?
1150================================
Tim Petersd66595f2001-02-04 03:09:53 +00001151
1152Core language, builtins, and interpreter
1153
Guido van Rossum9d0fbde2001-03-02 14:00:32 +00001154- Following an outcry from the community about the amount of code
1155 broken by the nested scopes feature introduced in 2.1a2, we decided
1156 to make this feature optional, and to wait until Python 2.2 (or at
1157 least 6 months) to make it standard. The option can be enabled on a
1158 per-module basis by adding "from __future__ import nested_scopes" at
1159 the beginning of a module (before any other statements, but after
1160 comments and an optional docstring). See PEP 236 (Back to the
1161 __future__) for a description of the __future__ statement. PEP 227
1162 (Statically Nested Scopes) has been updated to reflect this change,
1163 and to clarify the semantics in a number of endcases.
1164
1165- The nested scopes code, when enabled, has been hardened, and most
1166 bugs and memory leaks in it have been fixed.
1167
1168- Compile-time warnings are now generated for a number of conditions
1169 that will break or change in meaning when nested scopes are enabled:
1170
1171 - Using "from...import *" or "exec" without in-clause in a function
1172 scope that also defines a lambda or nested function with one or
1173 more free (non-local) variables. The presence of the import* or
1174 bare exec makes it impossible for the compiler to determine the
1175 exact set of local variables in the outer scope, which makes it
1176 impossible to determine the bindings for free variables in the
1177 inner scope. To avoid the warning about import *, change it into
1178 an import of explicitly name object, or move the import* statement
1179 to the global scope; to avoid the warning about bare exec, use
1180 exec...in... (a good idea anyway -- there's a possibility that
1181 bare exec will be deprecated in the future).
1182
1183 - Use of a global variable in a nested scope with the same name as a
1184 local variable in a surrounding scope. This will change in
1185 meaning with nested scopes: the name in the inner scope will
1186 reference the variable in the outer scope rather than the global
1187 of the same name. To avoid the warning, either rename the outer
1188 variable, or use a global statement in the inner function.
1189
Neil Schemenauera35c6882001-02-27 04:45:05 +00001190- An optional object allocator has been included. This allocator is
1191 optimized for Python objects and should be faster and use less memory
1192 than the standard system allocator. It is not enabled by default
1193 because of possible thread safety problems. The allocator is only
1194 protected by the Python interpreter lock and it is possible that some
1195 extension modules require a thread safe allocator. The object
1196 allocator can be enabled by providing the "--with-pymalloc" option to
1197 configure.
1198
Tim Petersd66595f2001-02-04 03:09:53 +00001199Standard library
1200
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001201- pyexpat now detects the expat version if expat.h defines it. A
1202 number of additional handlers are provided, which are only available
1203 since expat 1.95. In addition, the methods SetParamEntityParsing and
1204 GetInputContext of Parser objects are available with 1.95.x
1205 only. Parser objects now provide the ordered_attributes and
1206 specified_attributes attributes. A new module expat.model was added,
1207 which offers a number of additional constants if 1.95.x is used.
1208
1209- xml.dom offers the new functions registerDOMImplementation and
1210 getDOMImplementation.
1211
1212- xml.dom.minidom offers a toprettyxml method. A number of DOM
1213 conformance issues have been resolved. In particular, Element now
1214 has an hasAttributes method, and the handling of namespaces was
1215 improved.
1216
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001217- Ka-Ping Yee contributed two new modules: inspect.py, a module for
1218 getting information about live Python code, and pydoc.py, a module
1219 for interactively converting docstrings to HTML or text.
1220 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +00001221 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +00001222 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
1223 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +00001224
Tim Peters1eff7962001-03-01 02:31:33 +00001225- New library module difflib.py, primarily packaging the SequenceMatcher
1226 class at the heart of the popular ndiff.py file-comparison tool.
1227
1228- doctest.py (a framework for verifying Python code examples in docstrings)
1229 is now part of the std library.
1230
Tim Petersd66595f2001-02-04 03:09:53 +00001231Windows changes
1232
Guido van Rossume3955a82001-03-02 14:05:59 +00001233- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
1234 small GUI that lets you browse the module docstrings using your
1235 default web browser.
1236
Tim Peters1eff7962001-03-01 02:31:33 +00001237- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
1238 Platforms) is implemented. See
1239
1240 http://python.sourceforge.net/peps/pep-0235.html
1241
1242 for full details, especially the "Current Lower-Left Semantics" section.
1243 The new Windows import rules are simpler than before:
1244
1245 A. If the PYTHONCASEOK environment variable exists, same as
1246 before: silently accept the first case-insensitive match of any
1247 kind; raise ImportError if none found.
1248
1249 B. Else search sys.path for the first case-sensitive match; raise
1250 ImportError if none found.
1251
1252 The same rules have been implented on other platforms with case-
1253 insensitive but case-preserving filesystems too (including Cygwin, and
1254 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +00001255
Tim Peters25a9ce32001-02-19 07:06:36 +00001256- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
1257 what it's supposed to do (and does do under NT and 2000) via direct
1258 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +00001259 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +00001260 all Win9x systems before.
1261
Tim Peters1eff7962001-03-01 02:31:33 +00001262- Build: Subproject _test (effectively) renamed to _testcapi.
1263
Tim Peters2fe289a2001-03-01 22:19:38 +00001264New platforms
1265
1266- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
1267 Thanks to Steven Majewski!
1268
1269- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
1270 Tishler!
1271
Guido van Rossum9089b272001-03-02 06:49:50 +00001272- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
1273 Schwertberger! See RISCOS/README for more information -- it seems
1274 that because of the bizarre filename conventions on RISCOS, no port
1275 to that platform is easy. Note that the new variable os.endsep is
1276 silently supported in order to make life easier on this platform,
1277 but we don't advertise it because it's not worth for most folks to
1278 care about RISCOS portability.
1279
Tim Peters25a9ce32001-02-19 07:06:36 +00001280
Tim Petersd7b5e882001-01-25 03:36:26 +00001281What's New in Python 2.1 alpha 2?
1282=================================
Tim Peters40ead762001-01-27 05:35:26 +00001283
Tim Petersd7b5e882001-01-25 03:36:26 +00001284Core language, builtins, and interpreter
1285
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001286- Scopes nest. If a name is used in a function or class, but is not
1287 local, the definition in the nearest enclosing function scope will
1288 be used. One consequence of this change is that lambda statements
1289 could reference variables in the namespaces where the lambda is
1290 defined. In some unusual cases, this change will break code.
1291
1292 In all previous version of Python, names were resolved in exactly
1293 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001294 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +00001295 function A is defined within a function B, the names bound in B are
1296 not visible in A. The new rules make names bound in B visible in A,
1297 unless A contains a name binding that hides the binding in B.
1298
1299 Section 4.1 of the reference manual describes the new scoping rules
1300 in detail. The test script in Lib/test/test_scope.py demonstrates
1301 some of the effects of the change.
1302
1303 The new rules will cause existing code to break if it defines nested
1304 functions where an outer function has local variables with the same
1305 name as globals or builtins used by the inner function. Example:
1306
1307 def munge(str):
1308 def helper(x):
1309 return str(x)
1310 if type(str) != type(''):
1311 str = helper(str)
1312 return str.strip()
1313
1314 Under the old rules, the name str in helper() is bound to the
1315 builtin function str(). Under the new rules, it will be bound to
1316 the argument named str and an error will occur when helper() is
1317 called.
1318
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001319- The compiler will report a SyntaxError if "from ... import *" occurs
1320 in a function or class scope. The language reference has documented
1321 that this case is illegal, but the compiler never checked for it.
1322 The recent introduction of nested scope makes the meaning of this
1323 form of name binding ambiguous. In a future release, the compiler
1324 may allow this form when there is no possibility of ambiguity.
1325
Tim Peters40ead762001-01-27 05:35:26 +00001326- repr(string) is easier to read, now using hex escapes instead of octal,
1327 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1328
1329 >>> "\texample \r\n" + chr(0) + chr(255)
1330 '\texample \r\n\x00\xff' # in 2.1
1331 '\011example \015\012\000\377' # in 2.0
1332
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001333- Functions are now compared and hashed by identity, not by value, since
1334 the func_code attribute is writable.
1335
Fred Drakefb9d7122001-02-01 20:00:40 +00001336- Weak references (PEP 205) have been added. This involves a few
1337 changes in the core, an extension module (_weakref), and a Python
1338 module (weakref). The weakref module is the public interface. It
1339 includes support for "explicit" weak references, proxy objects, and
1340 mappings with weakly held values.
1341
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001342- A 'continue' statement can now appear in a try block within the body
1343 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001344 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001345
Tim Petersd7b5e882001-01-25 03:36:26 +00001346Standard library
1347
Barry Warsaw30dbd142001-01-31 22:14:01 +00001348- mailbox.py now has a new class, PortableUnixMailbox which is
1349 identical to UnixMailbox but uses a more portable scheme for
1350 determining From_ separators. Also, the constructors for all the
1351 classes in this module have a new optional `factory' argument, which
1352 is a callable used when new message classes must be instantiated by
1353 the next() method.
1354
Tim Petersd7b5e882001-01-25 03:36:26 +00001355- random.py is now self-contained, and offers all the functionality of
1356 the now-deprecated whrandom.py. See the docs for details. random.py
1357 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001358 and restoring the internal state of the generator; and jumpahead(n),
1359 for quickly forcing the internal state to be the same as if n calls to
1360 random() had been made. The latter is particularly useful for multi-
1361 threaded programs, creating one instance of the random.Random() class for
1362 each thread, then using .jumpahead() to force each instance to use a
1363 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001364
Tim Peters0de88fc2001-02-01 04:59:18 +00001365- random.py's seed() function is new. For bit-for-bit compatibility with
1366 prior releases, use the whseed function instead. The new seed function
1367 addresses two problems: (1) The old function couldn't produce more than
1368 about 2**24 distinct internal states; the new one about 2**45 (the best
1369 that can be done in the Wichmann-Hill generator). (2) The old function
1370 sometimes produced identical internal states when passed distinct
1371 integers, and there was no simple way to predict when that would happen;
1372 the new one guarantees to produce distinct internal states for all
1373 arguments in [0, 27814431486576L).
1374
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001375- The socket module now supports raw packets on Linux. The socket
1376 family is AF_PACKET.
1377
Tim Peters9ea17ac2001-02-02 05:57:15 +00001378- test_capi.py is a start at running tests of the Python C API. The tests
1379 are implemented by the new Modules/_testmodule.c.
1380
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001381- A new extension module, _symtable, provides provisional access to the
1382 internal symbol table used by the Python compiler. A higher-level
1383 interface will be added on top of _symtable in a future release.
1384
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001385- Removed the obsolete soundex module.
1386
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001387- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1388 the isSameNode method; NamedNodeMap the get method.
1389
1390- xml.sax.expatreader supports the lexical handler property; it
1391 generates comment, startCDATA, and endCDATA events.
1392
Tim Petersee826f82001-01-31 19:39:44 +00001393Windows changes
1394
1395- Build procedure: the zlib project is built in a different way that
1396 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001397 the zlib binary used. See PCbuild\readme.txt for details. Your old
1398 zlib-related directories can be deleted; you'll need to download fresh
1399 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001400
Tim Peters9ea17ac2001-02-02 05:57:15 +00001401- Build: New subproject _test for the benefit of test_capi.py (see above).
1402
Tim Petersb16c56f2001-02-02 21:24:51 +00001403- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1404 interface to some Python compiler internals).
1405
1406- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001407 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001408
Tim Petersa3a3a032000-11-30 05:22:44 +00001409What's New in Python 2.1 alpha 1?
1410=================================
1411
1412Core language, builtins, and interpreter
1413
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001414- There is a new Unicode companion to the PyObject_Str() API
1415 called PyObject_Unicode(). It behaves in the same way as the
1416 former, but assures that the returned value is an Unicode object
1417 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001418
Guido van Rossumf98eda02001-01-17 15:54:45 +00001419- The comparison operators support "rich comparison overloading" (PEP
1420 207). C extension types can provide a rich comparison function in
1421 the new tp_richcompare slot in the type object. The cmp() function
1422 and the C function PyObject_Compare() first try the new rich
1423 comparison operators before trying the old 3-way comparison. There
1424 is also a new C API PyObject_RichCompare() (which also falls back on
1425 the old 3-way comparison, but does not constrain the outcome of the
1426 rich comparison to a Boolean result).
1427
1428 The rich comparison function takes two objects (at least one of
1429 which is guaranteed to have the type that provided the function) and
1430 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1431 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1432 object, which may be NotImplemented (in which case the tp_compare
1433 slot function is used as a fallback, if defined).
1434
1435 Classes can overload individual comparison operators by defining one
1436 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001437 __ge__. There are no explicit "reflected argument" versions of
1438 these; instead, __lt__ and __gt__ are each other's reflection,
1439 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1440 reflection (similar at the C level). No other implications are
1441 made; in particular, Python does not assume that == is the Boolean
1442 inverse of !=, or that < is the Boolean inverse of >=. This makes
1443 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001444
1445 Classes or types that want to implement (in)equality tests but not
1446 the ordering operators (i.e. unordered types) should implement ==
1447 and !=, and raise an error for the ordering operators.
1448
Guido van Rossuma88479f2001-01-18 14:28:08 +00001449 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001450 Boolean; e.g. a matrix type might want to return a matrix of bits
1451 for A < B, giving elementwise comparisons. Such types should ensure
1452 that any interpretation of their value in a Boolean context raises
1453 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1454 at the C level) to always raise an exception.
1455
Guido van Rossuma88479f2001-01-18 14:28:08 +00001456- Complex numbers use rich comparisons to define == and != but raise
1457 an exception for <, <=, > and >=. Unfortunately, this also means
1458 that cmp() of two complex numbers raises an exception when the two
1459 numbers differ. Since it is not mathematically meaningful to compare
1460 complex numbers except for equality, I hope that this doesn't break
1461 too much code.
1462
Tim Peters3389f192001-02-18 08:48:49 +00001463- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001464 not defined by the language, other than that it's arbitrary but
1465 consistent (see the Reference Manual). An implementation detail changed
1466 in 2.1a1 such that None now compares less than any other object. Code
1467 relying on this new behavior (like code that relied on the previous
1468 behavior) does so at its own risk.
1469
Barry Warsaw573b5412001-01-15 20:43:18 +00001470- Functions and methods now support getting and setting arbitrarily
1471 named attributes (PEP 232). Functions have a new __dict__
1472 (a.k.a. func_dict) which hold the function attributes. Methods get
1473 and set attributes on their underlying im_func. It is a TypeError
1474 to set an attribute on a bound method.
1475
Guido van Rossum051e3352001-01-15 19:11:10 +00001476- The xrange() object implementation has been improved so that
1477 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1478 limitation that in this case len(xrange(sys.maxint)) can't be
1479 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1480 work fine as long as the index i doesn't actually reach 2**31.
1481 (Python uses regular ints for sequence and string indices; fixing
1482 that is much more work.)
1483
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001484- Two changes to from...import:
1485
Guido van Rossumba381232001-02-03 15:06:40 +00001486 1) "from M import X" now works even if (after loading module M)
1487 sys.modules['M'] is not a real module; it's basically a getattr()
1488 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001489
1490 2) "from M import *" now looks for M.__all__ to decide which names to
1491 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1492 filters out names starting with '_' as before. Whether or not
1493 __all__ exists, there's no restriction on the type of M.
1494
Guido van Rossumf61f1662001-01-10 20:13:55 +00001495- File objects have a new method, xreadlines(). This is the fastest
1496 way to iterate over all lines in a file:
1497
1498 for line in file.xreadlines():
1499 ...do something to line...
1500
1501 See the xreadlines module (mentioned below) for how to do this for
1502 other file-like objects.
1503
1504- Even if you don't use file.xreadlines(), you may expect a speedup on
1505 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001506 quite a bit in platform-specific ways: on systems (like Linux) that
1507 support flockfile(), getc_unlocked(), and funlockfile(), those are
1508 used by default. On systems (like Windows) without getc_unlocked(),
1509 a complicated (but still thread-safe) method using fgets() is used by
1510 default.
1511
Tim Petersd52269b2001-01-25 06:23:18 +00001512 You can force use of the fgets() method by #define'ing
1513 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001514 getc_unlocked()).
1515
Tim Petersd52269b2001-01-25 06:23:18 +00001516 You can force fgets() not to be used by #define'ing
1517 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001518 test_bufio.py fails -- and let us know if it does!).
1519
1520- In addition, the fileinput module, while still slower than the other
1521 methods on most platforms, has been sped up too, by using
1522 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001523
1524- Support for run-time warnings has been added, including a new
1525 command line option (-W) to specify the disposition of warnings.
1526 See the description of the warnings module below.
1527
1528- Extensive changes have been made to the coercion code. This mostly
1529 affects extension modules (which can now implement mixed-type
1530 numerical operators without having to use coercion), but
1531 occasionally, in boundary cases the coercion semantics have changed
1532 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001533 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001534 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001535 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001536
Guido van Rossumf98eda02001-01-17 15:54:45 +00001537- In connection with the coercion changes, a new built-in singleton
1538 object, NotImplemented is defined. This can be returned for
1539 operations that wish to indicate they are not implemented for a
1540 particular combination of arguments. From C, this is
1541 Py_NotImplemented.
1542
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001543- The interpreter accepts now bytecode files on the command line even
1544 if they do not have a .pyc or .pyo extension. On Linux, after executing
1545
Martin v. Löwise214baa2001-02-04 22:37:56 +00001546import imp,sys,string
1547magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1548reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1549open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001550
1551 any byte code file can be used as an executable (i.e. as an argument
1552 to execve(2)).
1553
Tim Peters9940b802000-12-01 07:59:35 +00001554- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001555 character. In 1.6 and earlier, they never produced a sign,
1556 and raised an error if the value of the long was too large
1557 to fit in a Python int. In 2.0, they produced a sign if and
1558 only if too large to fit in an int. This was inconsistent
1559 across platforms (because the size of an int varies across
1560 platforms), and inconsistent with hex() and oct(). Example:
1561
1562 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001563 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001564 'ffffffbe' # in 2.0 and before, on 32-bit machines
1565 >>> hex(-0x42L)
1566 '-0x42L' # in all versions of Python
1567
Tim Peters9940b802000-12-01 07:59:35 +00001568 The behavior of %d formats for negative Python longs remains
1569 the same as in 2.0 (although in 1.6 and before, they raised
1570 an error if the long didn't fit in a Python int).
1571
1572 %u formats don't make sense for Python longs, but are allowed
1573 and treated the same as %d in 2.1. In 2.0, a negative long
1574 formatted via %u produced a sign if and only if too large to
1575 fit in an int. In 1.6 and earlier, a negative long formatted
1576 via %u raised an error if it was too big to fit in an int.
1577
Guido van Rossum3661d392000-12-12 22:10:31 +00001578- Dictionary objects have an odd new method, popitem(). This removes
1579 an arbitrary item from the dictionary and returns it (in the form of
1580 a (key, value) pair). This can be useful for algorithms that use a
1581 dictionary as a bag of "to do" items and repeatedly need to pick one
1582 item. Such algorithms normally end up running in quadratic time;
1583 using popitem() they can usually be made to run in linear time.
1584
Tim Peters36cdad12000-12-29 02:06:45 +00001585Standard library
1586
Thomas Woutersfe385252001-01-19 23:16:56 +00001587- In the time module, the time argument to the functions strftime,
1588 localtime, gmtime, asctime and ctime is now optional, defaulting to
1589 the current time (in the local timezone).
1590
Guido van Rossumda91f222001-01-15 16:36:08 +00001591- The ftplib module now defaults to passive mode, which is deemed a
1592 more useful default given that clients are often inside firewalls
1593 these days. Note that this could break if ftplib is used to connect
1594 to a *server* that is inside a firewall, from outside; this is
1595 expected to be a very rare situation. To fix that, you can call
1596 ftp.set_pasv(0).
1597
Martin v. Löwis10a27872001-01-13 09:54:41 +00001598- The module site now treats .pth files not only for path configuration,
1599 but also supports extensions to the initialization code: Lines starting
1600 with import are executed.
1601
Guido van Rossumf61f1662001-01-10 20:13:55 +00001602- There's a new module, warnings, which implements a mechanism for
1603 issuing and filtering warnings. There are some new built-in
1604 exceptions that serve as warning categories, and a new command line
1605 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1606 turns warnings into errors). warnings.warn(message[, category])
1607 issues a warning message; this can also be called from C as
1608 PyErr_Warn(category, message).
1609
1610- A new module xreadlines was added. This exports a single factory
1611 function, xreadlines(). The intention is that this code is the
1612 absolutely fastest way to iterate over all lines in an open
1613 file(-like) object:
1614
1615 import xreadlines
1616 for line in xreadlines.xreadlines(file):
1617 ...do something to line...
1618
1619 This is equivalent to the previous the speed record holder using
1620 file.readlines(sizehint). Note that if file is a real file object
1621 (as opposed to a file-like object), this is equivalent:
1622
1623 for line in file.xreadlines():
1624 ...do something to line...
1625
Tim Peters36cdad12000-12-29 02:06:45 +00001626- The bisect module has new functions bisect_left, insort_left,
1627 bisect_right and insort_right. The old names bisect and insort
1628 are now aliases for bisect_right and insort_right. XXX_right
1629 and XXX_left methods differ in what happens when the new element
1630 compares equal to one or more elements already in the list: the
1631 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001632 right. Code that doesn't care where equal elements end up should
1633 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001634
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001635- The new curses.panel module wraps the panel library that forms part
1636 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1637
Guido van Rossumf61f1662001-01-10 20:13:55 +00001638- The SocketServer module now sets the allow_reuse_address flag by
1639 default in the TCPServer class.
1640
1641- A new function, sys._getframe(), returns the stack frame pointer of
1642 the caller. This is intended only as a building block for
1643 higher-level mechanisms such as string interpolation.
1644
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001645- The pyexpat module supports a number of new handlers, which are
1646 available only in expat 1.2. If invocation of a callback fails, it
1647 will report an additional frame in the traceback. Parser objects
1648 participate now in garbage collection. If expat reports an unknown
1649 encoding, pyexpat will try to use a Python codec; that works only
1650 for single-byte charsets. The parser type objects is exposed as
1651 XMLParserObject.
1652
1653- xml.dom now offers standard definitions for symbolic node type and
1654 exception code constants, and a hierarchy of DOM exceptions. minidom
1655 was adjusted to use them.
1656
1657- The conformance of xml.dom.minidom to the DOM specification was
1658 improved. It detects a number of additional error cases; the
1659 previous/next relationship works even when the tree is modified;
1660 Node supports the normalize() method; NamedNodeMap, DocumentType and
1661 DOMImplementation classes were added; Element supports the
1662 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1663 method.
1664
Guido van Rossumf61f1662001-01-10 20:13:55 +00001665Build issues
1666
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001667- For Unix (and Unix-compatible) builds, configuration and building of
1668 extension modules is now greatly automated. Rather than having to
1669 edit the Modules/Setup file to indicate which modules should be
1670 built and where their include files and libraries are, a
1671 distutils-based setup.py script now takes care of building most
1672 extension modules. All extension modules built this way are built
1673 as shared libraries. Only a few modules that must be linked
1674 statically are still listed in the Setup file; you won't need to
1675 edit their configuration.
1676
1677- Python should now build out of the box on Cygwin. If it doesn't,
1678 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001679
1680- Python now always uses its own (renamed) implementation of getopt()
1681 -- there's too much variation among C library getopt()
1682 implementations.
1683
1684- C++ compilers are better supported; the CXX macro is always set to a
1685 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001686
Tim Petersd92dfe02000-12-12 01:18:41 +00001687Windows changes
1688
1689- select module: By default under Windows, a select() call
1690 can specify no more than 64 sockets. Python now boosts
1691 this Microsoft default to 512. If you need even more than
1692 that, see the MS docs (you'll need to #define FD_SETSIZE
1693 and recompile Python from source).
1694
Guido van Rossumf61f1662001-01-10 20:13:55 +00001695- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1696 subdirectory is no more!
1697
Tim Petersa3a3a032000-11-30 05:22:44 +00001698
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001699What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001700=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001701
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001702Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001703changes are in the file HISTORY. If you are making the jump directly
1704from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1705HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001706
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001707Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1708the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1709http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001710
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001711--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001712
1713======================================================================
1714
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001715What's new in 2.0 (since release candidate 1)?
1716==============================================
1717
1718Standard library
1719
1720- The copy_reg module was modified to clarify its intended use: to
1721 register pickle support for extension types, not for classes.
1722 pickle() will raise a TypeError if it is passed a class.
1723
1724- Fixed a bug in gettext's "normalize and expand" code that prevented
1725 it from finding an existing .mo file.
1726
1727- Restored support for HTTP/0.9 servers in httplib.
1728
Tim Peters989b7b92000-10-16 20:24:53 +00001729- The math module was changed to stop raising OverflowError in case of
1730 underflow, and return 0 instead in underflow cases. Whether Python
1731 used to raise OverflowError in case of underflow was platform-
1732 dependent (it did when the platform math library set errno to ERANGE
1733 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001734
1735- Fixed a bug in StringIO that occurred when the file position was not
1736 at the end of the file and write() was called with enough data to
1737 extend past the end of the file.
1738
1739- Fixed a bug that caused Tkinter error messages to get lost on
1740 Windows. The bug was fixed by replacing direct use of
1741 interp->result with Tcl_GetStringResult(interp).
1742
1743- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1744 redirect response.
1745
1746- Several changes were made to distutils: Some debugging code was
1747 removed from util. Fixed the installer used when an external zip
1748 program (like WinZip) is not found; the source code for this
1749 installer is in Misc/distutils. check_lib() was modified to behave
1750 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1751 test for whether installed modules are on sys.path was changed to
1752 use both normcase() and normpath().
1753
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001754- Several minor bugs were fixed in the xml package (the minidom,
1755 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001756
1757- The regression test driver (regrtest.py) behavior when invoked with
1758 -l changed: It now reports a count of objects that are recognized as
1759 garbage but not freed by the garbage collector.
1760
Tim Peters989b7b92000-10-16 20:24:53 +00001761- The regression test for the math module was changed to test
1762 exceptional behavior when the test is run in verbose mode. Python
1763 cannot yet guarantee consistent exception behavior across platforms,
1764 so the exception part of test_math is run only in verbose mode, and
1765 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001766
1767Internals
1768
1769- PyOS_CheckStack() has been disabled on Win64, where it caused
1770 test_sre to fail.
1771
1772Build issues
1773
1774- Changed compiler flags, so that gcc is always invoked with -Wall and
1775 -Wstrict-prototypes. Users compiling Python with GCC should see
1776 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001777 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001778 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001779
Tim Petersa3a3a032000-11-30 05:22:44 +00001780- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001781
1782Tools and other miscellany
1783
1784- The compiler in Tools/compiler was updated to support the new
1785 language features introduced in 2.0: extended print statement, list
1786 comprehensions, and augmented assignments. The new compiler should
1787 also be backwards compatible with Python 1.5.2; the compiler will
1788 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001789 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001790
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001791What's new in 2.0 release candidate 1 (since beta 2)?
1792=====================================================
1793
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001794What is release candidate 1?
1795
1796We believe that release candidate 1 will fix all known bugs that we
1797intend to fix for the 2.0 final release. This release should be a bit
1798more stable than the previous betas. We would like to see even more
1799widespread testing before the final release, so we are producing this
1800release candidate. The final release will be exactly the same unless
1801any show-stopping (or brown bag) bugs are found by testers of the
1802release candidate.
1803
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001804All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001805to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001806
1807Core language, builtins, and interpreter
1808
1809- A bug that caused crashes when __coerce__ was used with augmented
1810 assignment, e.g. +=, was fixed.
1811
1812- Raise ZeroDivisionError when raising zero to a negative number,
1813 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1814 power operator and the result of math.pow(0.0, -2.0) will vary by
1815 platform. On Linux, it raises a ValueError.
1816
1817- A bug in Unicode string interpolation was fixed that occasionally
1818 caused errors with formats including "%%". For example, the
1819 following expression "%% %s" % u"abc" no longer raises a TypeError.
1820
1821- Compilation of deeply nested expressions raises MemoryError instead
1822 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1823
1824- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1825 rendering them useless. They are now written in binary mode again.
1826
1827Standard library
1828
1829- Keyword arguments are now accepted for most pattern and match object
1830 methods in SRE, the standard regular expression engine.
1831
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001832- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001833 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001834
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001835- Several bugs in the Unicode handling and error handling in _tkinter
1836 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001837
1838- Fix memory management errors in Merge() and Tkapp_Call() routines.
1839
1840- Several changes were made to cStringIO to make it compatible with
1841 the file-like object interface and with StringIO. If operations are
1842 performed on a closed object, an exception is raised. The truncate
1843 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001844 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001845
1846- There were many changes made to the linuxaudiodev module and its
1847 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001848 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001849
1850 Note that this module is named poorly, because it should work
1851 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001852 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001853
1854 The module now raises exceptions when errors occur instead of
1855 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1856 audio) and defines a getptr() method that calls the
1857 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1858
1859- The library_version attribute, introduced in an earlier beta, was
1860 removed because it can not be supported with early versions of the C
1861 readline library, which provides no way to determine the version at
1862 compile-time.
1863
1864- The binascii module is now enabled on Win64.
1865
Tim Peters46446d62000-10-09 21:19:31 +00001866- tokenize.py no longer suffers "recursion depth" errors when parsing
1867 programs with very long string literals.
1868
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001869Internals
1870
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001871- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001872 which is called when the interpreter starts up to determine where
1873 the standard library is installed. These vulnerabilities affect all
1874 previous versions of Python and can be exploited by setting very
1875 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1876 setuid Python script, although use of the wrapper in
1877 Misc/setuid-prog.c will eliminate the vulnerability.
1878
1879- Fixed garbage collection bugs in instance creation that were
1880 triggered when errors occurred during initialization. The solution,
1881 applied in cPickle and in PyInstance_New(), is to call
1882 PyObject_GC_Init() after the initialization of the object's
1883 container attributes is complete.
1884
1885- pyexpat adds definitions of PyModule_AddStringConstant and
1886 PyModule_AddObject if the Python version is less than 2.0, which
1887 provides compatibility with PyXML on Python 1.5.2.
1888
1889- If the platform has a bogus definition for LONG_BIT (the number of
1890 bits in a long), an error will be reported at compile time.
1891
1892- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1893 collection crashes and possibly other, unreported crashes.
1894
1895- Fixed a memory leak in _PyUnicode_Fini().
1896
1897Build issues
1898
1899- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001900 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001901 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001902
1903- The mmap.PAGESIZE constant is now initialized using sysconf when
1904 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1905
1906- The md5 file should now compile on all platforms.
1907
1908- The select module now compiles on platforms that do not define
1909 POLLRDNORM and related constants.
1910
1911- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001912 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001913
Jeremy Hylton10921202000-10-09 18:34:12 +00001914- BeOS: A number of changes were made to the build and installation
1915 process. ar-fake now operates on a directory of object files.
1916 dl_export.h is gone, and its macros now appear on the mwcc command
1917 line during build on PPC BeOS.
1918
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001919- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001920 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001921
1922- Cygwin: Support for shared libraries, Tkinter, and sockets.
1923
1924- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1925
1926Tools and other miscellany
1927
1928- Removed debugging prints from main used with freeze.
1929
Tim Peters46446d62000-10-09 21:19:31 +00001930- IDLE auto-indent no longer crashes when it encounters Unicode
1931 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001932
1933What's new in 2.0 beta 2 (since beta 1)?
1934========================================
1935
1936Core language, builtins, and interpreter
1937
Tim Peters482c0212000-09-26 06:33:09 +00001938- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001939 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001940
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001941- Add -h and -V command line options to print the usage message and
1942 Python version number and exit immediately.
1943
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001944- eval() and exec accept Unicode objects as code parameters.
1945
1946- getattr() and setattr() now also accept Unicode objects for the
1947 attribute name, which are converted to strings using the default
1948 encoding before lookup.
1949
1950- Multiplication on string and Unicode now does proper bounds
1951 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1952 string is too long."
1953
1954- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001955 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001956
Jeremy Hylton1b618592000-09-26 05:32:36 +00001957
1958Standard library and extensions
1959
Guido van Rossum5b08f132001-04-16 02:05:23 +00001960- socket module: the OpenSSL code now adds support for RAND_status()
1961 and EGD (Entropy Gathering Device).
1962
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001963- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001964 argument checking; it still takes no arguments.
1965
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001966- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001967
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001968- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001969
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001970- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001971
1972- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001973 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001974
1975- copy: Copy Unicode objects atomically.
1976
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001977- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001978
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001979- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001980
Fred Drake67233bc2000-09-26 16:40:27 +00001981- dbm: Add get() and setdefault() methods to dbm object. Add constant
1982 `library' to module that names the library used. Added doc strings
1983 and method names to error messages. Uses configure to determine
1984 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
1985 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001986
1987- distutils: Update to version 0.9.3.
1988
1989- dl: Add several dl.RTLD_ constants.
1990
1991- fpectl: Now supported on FreeBSD.
1992
1993- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
1994 found by the collector will be saved in gc.garbage. This is useful
1995 for debugging a program that creates reference cycles.
1996
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001997- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00001998 of HTTP class. Do not close socket on zero-length response. Do not
1999 crash when server sends invalid content-length header.
2000
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002001- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002002
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002003- marshal: When reading a short, sign-extend on platforms where shorts
2004 are bigger than 16 bits. When reading a long, repair the unportable
2005 sign extension that was being done for 64-bit machines. (It assumed
2006 that signed right shift sign-extends.)
2007
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002008- operator: Add contains(), invert(), __invert__() as aliases for
2009 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002010
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002011- os: Add support for popen2() and popen3() on all platforms where
2012 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002013
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002014- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00002015 clicking on a file in Explorer (or passing the file name to the
2016 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002017
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002018- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00002019 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00002020
2021- pickle: Now raises ValueError when an invalid pickle that contains
2022 a non-string repr where a string repr was expected. This behavior
2023 matches cPickle.
2024
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002025- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002026
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002027- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002028
2029- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002030 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002031 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00002032
2033- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002034 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002035
2036- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00002037 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00002038 few cycles during startup since the first call to
2039 setdefaultencoding() will initialize the codec registry and the
2040 encodings package.
2041
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002042- socket: Support for size hint in readlines() method of object returned
2043 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002044
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002045- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00002046 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00002047 is followed by whitespace.
2048
Tim Petersa3a3a032000-11-30 05:22:44 +00002049- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002050
2051- struct: Check ranges for bytes and shorts.
2052
2053- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002054 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002055
2056- Tkinter: Image objects are now guaranteed to have unique ids. Set
2057 event.delta to zero if Tk version doesn't support mousewheel.
2058 Removed some debugging prints.
2059
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002060- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00002061
Fred Drake67233bc2000-09-26 16:40:27 +00002062- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002063 which works around a bug in Norton AntiVirus 2000 that leads directly
2064 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002065
2066- xml: New version detection code allows PyXML to override standard
2067 XML package if PyXML version is greater than 0.6.1.
2068
Fred Drake64bb3802000-09-26 16:21:35 +00002069- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
2070 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
2071 tree only for nodes which are sufficiently interesting to a specific
2072 application. Does not provide the HTML-specific extensions. Still
2073 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002074
Fred Drake64bb3802000-09-26 16:21:35 +00002075- xml.sax: SAX 2 support for Python, including all the handler
2076 interfaces needed to process XML 1.0 compliant XML. Some
2077 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002078
Fred Drake64bb3802000-09-26 16:21:35 +00002079- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
2080 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002081
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002082
Jeremy Hylton1b618592000-09-26 05:32:36 +00002083C API
2084
2085- Add three new convenience functions for module initialization --
2086 PyModule_AddObject(), PyModule_AddIntConstant(), and
2087 PyModule_AddStringConstant().
2088
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002089- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00002090 removed and add #error to Python.h if NULL isn't defined after
2091 #include of stdio.h.
2092
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002093- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00002094 backwards compatibility (at the source level) with old extensions.
2095
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002096- A wrapper API was added for signal() and sigaction(). Instead of
2097 either function, always use PyOS_getsig() to get a signal handler
2098 and PyOS_setsig() to set one. A new convenience typedef
2099 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002100
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002101- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00002102 internal data buffer and size of a string object -- or the default
2103 encoded version of a Unicode object.
2104
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002105- PyString_Size() and PyString_AsString() accept Unicode objects.
2106
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002107- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00002108 exists). INT_MAX and LONG_MAX will always be defined, even if
2109 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002110
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002111- PyFloat_FromString takes a second argument, pend, that was
2112 effectively useless. It is now officially useless but preserved for
2113 backwards compatibility. If the pend argument is not NULL, *pend is
2114 set to NULL.
2115
2116- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
2117 for the attribute name. See note on getattr() above.
2118
2119- A few bug fixes to argument processing for Unicode.
2120 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
2121 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
2122 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00002123 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002124
2125- Py_BuildValue accepts B format (for bgen-generated code).
2126
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002127
Jeremy Hylton1b618592000-09-26 05:32:36 +00002128Internals
2129
2130- On Unix, fix code for finding Python installation directory so that
2131 it works when argv[0] is a relative path.
2132
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00002133- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002134 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00002135 rather than by generating a copy of the object.
2136
Tim Peters482c0212000-09-26 06:33:09 +00002137- Several of the internal Unicode tables are much smaller now, and
2138 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002139
Jeremy Hylton97693b02000-09-26 17:42:51 +00002140- In the garbage collector: Fixed bug in collection of tuples. Fixed
2141 bug that caused some instances to be removed from the container set
2142 while they were still live. Fixed parsing in gc.set_debug() for
2143 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002144
2145- Fixed refcount problem in instance deallocation that only occurred
2146 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
2147
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002148- On Windows, getpythonregpath is now protected against null data in
2149 registry key.
2150
2151- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00002152 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002153
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002154
Jeremy Hylton1b618592000-09-26 05:32:36 +00002155Build and platform-specific issues
2156
2157- Better support of GNU Pth via --with-pth configure option.
2158
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002159- Python/C API now properly exposed to dynamically-loaded extension
2160 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00002161
2162- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
2163 Don't define MS_SYNC to be zero when it is undefined. Added missing
2164 prototypes in posixmodule.c.
2165
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002166- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002167 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00002168
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002169- Fix largefile support on older NetBSD systems and OpenBSD by adding
2170 define for TELL64.
2171
2172
2173Tools and other miscellany
2174
2175- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
2176
2177- freeze: The modulefinder now works with 2.0 opcodes.
2178
Tim Petersa3a3a032000-11-30 05:22:44 +00002179- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00002180 Move hackery of sys.argv until after the Tk instance has been
2181 created, which allows the application-specific Tkinter
2182 initialization to be executed if present; also pass an explicit
2183 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00002184
Jeremy Hylton1b618592000-09-26 05:32:36 +00002185
2186What's new in 2.0 beta 1?
2187=========================
2188
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002189Source Incompatibilities
2190------------------------
2191
2192None. Note that 1.6 introduced several incompatibilities with 1.5.2,
2193such as single-argument append(), connect() and bind(), and changes to
2194str(long) and repr(float).
2195
2196
2197Binary Incompatibilities
2198------------------------
2199
2200- Third party extensions built for Python 1.5.x or 1.6 cannot be used
2201with Python 2.0; these extensions will have to be rebuilt for Python
22022.0.
2203
2204- On Windows, attempting to import a third party extension built for
2205Python 1.5.x or 1.6 results in an immediate crash; there's not much we
2206can do about this. Check your PYTHONPATH environment variable!
2207
2208- Python bytecode files (*.pyc and *.pyo) are not compatible between
2209releases.
2210
2211
2212Overview of Changes Since 1.6
2213-----------------------------
2214
2215There are many new modules (including brand new XML support through
2216the xml package, and i18n support through the gettext module); a list
2217of all new modules is included below. Lots of bugs have been fixed.
2218
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002219The process for making major new changes to the language has changed
2220since Python 1.6. Enhancements must now be documented by a Python
2221Enhancement Proposal (PEP) before they can be accepted.
2222
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002223There are several important syntax enhancements, described in more
2224detail below:
2225
2226 - Augmented assignment, e.g. x += 1
2227
2228 - List comprehensions, e.g. [x**2 for x in range(10)]
2229
2230 - Extended import statement, e.g. import Module as Name
2231
2232 - Extended print statement, e.g. print >> file, "Hello"
2233
2234Other important changes:
2235
2236 - Optional collection of cyclical garbage
2237
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002238Python Enhancement Proposal (PEP)
2239---------------------------------
2240
2241PEP stands for Python Enhancement Proposal. A PEP is a design
2242document providing information to the Python community, or describing
2243a new feature for Python. The PEP should provide a concise technical
2244specification of the feature and a rationale for the feature.
2245
2246We intend PEPs to be the primary mechanisms for proposing new
2247features, for collecting community input on an issue, and for
2248documenting the design decisions that have gone into Python. The PEP
2249author is responsible for building consensus within the community and
2250documenting dissenting opinions.
2251
2252The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002253
2254Augmented Assignment
2255--------------------
2256
2257This must have been the most-requested feature of the past years!
2258Eleven new assignment operators were added:
2259
Guido van Rossume905e952000-09-05 12:42:46 +00002260 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002261
2262For example,
2263
2264 A += B
2265
2266is similar to
2267
2268 A = A + B
2269
2270except that A is evaluated only once (relevant when A is something
2271like dict[index].attr).
2272
2273However, if A is a mutable object, A may be modified in place. Thus,
2274if A is a number or a string, A += B has the same effect as A = A+B
2275(except A is only evaluated once); but if a is a list, A += B has the
2276same effect as A.extend(B)!
2277
2278Classes and built-in object types can override the new operators in
2279order to implement the in-place behavior; the not-in-place behavior is
2280used automatically as a fallback when an object doesn't implement the
2281in-place behavior. For classes, the method name is derived from the
2282method name for the corresponding not-in-place operator by inserting
2283an 'i' in front of the name, e.g. __iadd__ implements in-place
2284__add__.
2285
2286Augmented assignment was implemented by Thomas Wouters.
2287
2288
2289List Comprehensions
2290-------------------
2291
2292This is a flexible new notation for lists whose elements are computed
2293from another list (or lists). The simplest form is:
2294
2295 [<expression> for <variable> in <sequence>]
2296
Guido van Rossum56db0952000-09-06 23:34:25 +00002297For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002298This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002299
2300You can also add a condition:
2301
2302 [<expression> for <variable> in <sequence> if <condition>]
2303
2304For example, [w for w in words if w == w.lower()] would yield the list
2305of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002306than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002307
2308You can also have nested for loops and more than one 'if' clause. For
2309example, here's a function that flattens a sequence of sequences::
2310
2311 def flatten(seq):
2312 return [x for subseq in seq for x in subseq]
2313
2314 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2315
2316This prints
2317
2318 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2319
2320List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002321Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002322
2323
2324Extended Import Statement
2325-------------------------
2326
2327Many people have asked for a way to import a module under a different
2328name. This can be accomplished like this:
2329
2330 import foo
2331 bar = foo
2332 del foo
2333
2334but this common idiom gets old quickly. A simple extension of the
2335import statement now allows this to be written as follows:
2336
2337 import foo as bar
2338
2339There's also a variant for 'from ... import':
2340
2341 from foo import bar as spam
2342
2343This also works with packages; e.g. you can write this:
2344
2345 import test.regrtest as regrtest
2346
2347Note that 'as' is not a new keyword -- it is recognized only in this
2348context (this is only possible because the syntax for the import
2349statement doesn't involve expressions).
2350
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002351Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002352
2353
2354Extended Print Statement
2355------------------------
2356
2357Easily the most controversial new feature, this extension to the print
2358statement adds an option to make the output go to a different file
2359than the default sys.stdout.
2360
2361For example, to write an error message to sys.stderr, you can now
2362write:
2363
2364 print >> sys.stderr, "Error: bad dog!"
2365
2366As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002367evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002368
2369 print >> None, "Hello world"
2370
2371is equivalent to
2372
2373 print "Hello world"
2374
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002375Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002376
2377
2378Optional Collection of Cyclical Garbage
2379---------------------------------------
2380
2381Python is now equipped with a garbage collector that can hunt down
2382cyclical references between Python objects. It's no replacement for
2383reference counting; in fact, it depends on the reference counts being
2384correct, and decides that a set of objects belong to a cycle if all
2385their reference counts can be accounted for from their references to
2386each other. This devious scheme was first proposed by Eric Tiedemann,
2387and brought to implementation by Neil Schemenauer.
2388
2389There's a module "gc" that lets you control some parameters of the
2390garbage collection. There's also an option to the configure script
2391that lets you enable or disable the garbage collection. In 2.0b1,
2392it's on by default, so that we (hopefully) can collect decent user
2393experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002394performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002395off by default in the final 2.0 release.
2396
2397
2398Smaller Changes
2399---------------
2400
2401A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2402map(None, seq1, seq2, ...) when the sequences have the same length;
2403i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2404the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002405zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002406
2407sys.version_info is a tuple (major, minor, micro, level, serial).
2408
2409Dictionaries have an odd new method, setdefault(key, default).
2410dict.setdefault(key, default) returns dict[key] if it exists; if not,
2411it sets dict[key] to default and returns that value. Thus:
2412
2413 dict.setdefault(key, []).append(item)
2414
2415does the same work as this common idiom:
2416
2417 if not dict.has_key(key):
2418 dict[key] = []
2419 dict[key].append(item)
2420
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002421There are two new variants of SyntaxError that are raised for
2422indentation-related errors: IndentationError and TabError.
2423
2424Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2425escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002426
2427The limits on the size of expressions and file in Python source code
2428have been raised from 2**16 to 2**32. Previous versions of Python
2429were limited because the maximum argument size the Python VM accepted
2430was 2**16. This limited the size of object constructor expressions,
2431e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2432limit was raised thanks to a patch by Charles Waldman that effectively
2433fixes the problem. It is now much more likely that you will be
2434limited by available memory than by an arbitrary limit in Python.
2435
2436The interpreter's maximum recursion depth can be modified by Python
2437programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2438limit is the maximum number of recursive calls that can be made by
2439Python code. The limit exists to prevent infinite recursion from
2440overflowing the C stack and causing a core dump. The default value is
24411000. The maximum safe value for a particular platform can be found
2442by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002443
2444New Modules and Packages
2445------------------------
2446
2447atexit - for registering functions to be called when Python exits.
2448
2449imputil - Greg Stein's alternative API for writing custom import
2450hooks.
2451
2452pyexpat - an interface to the Expat XML parser, contributed by Paul
2453Prescod.
2454
2455xml - a new package with XML support code organized (so far) in three
2456subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2457would fill a volume. There's a special feature whereby a
2458user-installed package named _xmlplus overrides the standard
2459xmlpackage; this is intended to give the XML SIG a hook to distribute
2460backwards-compatible updates to the standard xml package.
2461
2462webbrowser - a platform-independent API to launch a web browser.
2463
2464
Guido van Rossume905e952000-09-05 12:42:46 +00002465Changed Modules
2466---------------
2467
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002468array -- new methods for array objects: count, extend, index, pop, and
2469remove
2470
2471binascii -- new functions b2a_hex and a2b_hex that convert between
2472binary data and its hex representation
2473
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002474calendar -- Many new functions that support features including control
2475over which day of the week is the first day, returning strings instead
2476of printing them. Also new symbolic constants for days of week,
2477e.g. MONDAY, ..., SUNDAY.
2478
2479cgi -- FieldStorage objects have a getvalue method that works like a
2480dictionary's get method and returns the value attribute of the object.
2481
2482ConfigParser -- The parser object has new methods has_option,
2483remove_section, remove_option, set, and write. They allow the module
2484to be used for writing config files as well as reading them.
2485
2486ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002487optionally support the RFC 959 REST command.
2488
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002489gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002490
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002491httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2492the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002493
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002494locale -- implement getdefaultlocale for Win32 and Macintosh
2495
2496marshal -- no longer dumps core when marshaling deeply nested or
2497recursive data structures
2498
2499os -- new functions isatty, seteuid, setegid, setreuid, setregid
2500
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002501os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2502support under Unix.
2503
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002504os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002505
2506os.path -- fix semantics of os.path.commonprefix
2507
2508smtplib -- support for sending very long messages
2509
2510socket -- new function getfqdn()
2511
2512readline -- new functions to read, write and truncate history files.
2513The readline section of the library reference manual contains an
2514example.
2515
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002516select -- add interface to poll system call
2517
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002518shutil -- new copyfileobj function
2519
2520SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2521HTTP server.
2522
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002523Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002524
2525urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002526e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002527
2528whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002529
2530
2531Obsolete Modules
2532----------------
2533
2534None. However note that 1.6 made a whole slew of modules obsolete:
2535stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2536poly, zmod, strop, util, whatsound.
2537
2538
2539Changed, New, Obsolete Tools
2540----------------------------
2541
Tim Peters8b092332000-09-05 20:15:25 +00002542None.
Guido van Rossume905e952000-09-05 12:42:46 +00002543
2544
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002545C-level Changes
2546---------------
2547
2548Several cleanup jobs were carried out throughout the source code.
2549
2550All C code was converted to ANSI C; we got rid of all uses of the
2551Py_PROTO() macro, which makes the header files a lot more readable.
2552
2553Most of the portability hacks were moved to a new header file,
2554pyport.h; several other new header files were added and some old
2555header files were removed, in an attempt to create a more rational set
2556of header files. (Few of these ever need to be included explicitly;
2557they are all included by Python.h.)
2558
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002559Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002560and Win64, especially for the new Intel Itanium processor. Mick also
2561added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002562
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002563The C APIs to return an object's size have been update to consistently
2564use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2565previous versions, the abstract interfaces used PyXXX_Length and the
2566concrete interfaces used PyXXX_Size. The old names,
2567e.g. PyObject_Length, are still available for backwards compatibility
2568at the API level, but are deprecated.
2569
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002570The PyOS_CheckStack function has been implemented on Windows by
2571Fredrik Lundh. It prevents Python from failing with a stack overflow
2572on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002573
2574The GC changes resulted in creation of two new slots on object,
2575tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002576the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002577
2578The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002579C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002580
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002581PyErr_Format has been updated to automatically calculate the size of
2582the buffer needed to hold the formatted result string. This change
2583prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002584
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002585New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002586
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002587PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2588that are the same as their non-Ex counterparts except they take an
2589extra flag argument that tells them to close the file when done.
2590
2591XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002592
Tim Peters8b092332000-09-05 20:15:25 +00002593
2594Windows Changes
2595---------------
2596
2597New popen2/popen3/peopen4 in os module (see Changed Modules above).
2598
2599os.popen is much more usable on Windows 95 and 98. See Microsoft
2600Knowledge Base article Q150956. The Win9x workaround described there
2601is implemented by the new w9xpopen.exe helper in the root of your
2602Python installation. Note that Python uses this internally; it is not
2603a standalone program.
2604
2605Administrator privileges are no longer required to install Python
2606on Windows NT or Windows 2000. If you have administrator privileges,
2607Python's registry info will be written under HKEY_LOCAL_MACHINE.
2608Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002609under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002610uses of Python, but will prevent some advanced uses from working
2611(for example, running a Python script as an NT service, or possibly
2612from CGI).
2613
2614[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2615installer; instead, it installs the needed Tcl/Tk files directly in the
2616Python directory. If you already have a Tcl/Tk installation, this
2617wastes some disk space (about 4 Megs) but avoids problems with
2618conflicting Tcl/Tk installations, and makes it much easier for Python
2619to ensure that Tcl/Tk can find all its files.
2620
2621[This was new in 1.6] The Windows installer now installs by default in
2622\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2623
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002624
2625Updates to the changes between 1.5.2 and 1.6
2626--------------------------------------------
2627
2628The 1.6 NEWS file can't be changed after the release is done, so here
2629is some late-breaking news:
2630
2631New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2632and changes to getlocale() and setlocale().
2633
2634The new module is now enabled per default.
2635
2636It is not true that the encodings codecs cannot be used for normal
2637strings: the string.encode() (which is also present on 8-bit strings
2638!) allows using them for 8-bit strings too, e.g. to convert files from
2639cp1252 (Windows) to latin-1 or vice-versa.
2640
2641Japanese codecs are available from Tamito KAJIYAMA:
2642http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2643
2644
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002645======================================================================