blob: 52b2a1effda1f1fa7450773fd6b0d0be21011c94 [file] [log] [blame]
Tim Petersedc99312001-08-22 21:36:50 +00001What's New in Python 2.2a3?
2===========================
3
4Core
5
Tim Peters9fffa3e2001-09-04 05:14:19 +00006- Conversion of long to float now raises OverflowError if the long is too
7 big to represent as a C double.
8
Tim Peters32f453e2001-09-03 08:35:41 +00009- The 3-argument builtin pow() no longer allows a third non-None argument
10 if either of the first two arguments is a float, or if both are of
11 integer types and the second argument is negative (in which latter case
12 the arguments are converted to float, so this is really the same
13 restriction).
14
Tim Peters5d2b77c2001-09-03 05:47:38 +000015- The builtin dir() now returns more information, and sometimes much
16 more, generally naming all attributes of an object, and all attributes
17 reachable from the object via its class, and from its class's base
18 classes, and so on from them too. Example: in 2.2a2, dir([]) returned
19 an empty list. In 2.2a3,
20
21 >>> dir([])
22 ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
23 '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
24 '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
25 '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
26 '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
27 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
28 'reverse', 'sort']
29
30 dir(module) continues to return only the module's attributes, though.
31
Tim Petersbdee63f2001-09-02 03:40:59 +000032- Overflowing operations on plain ints now return a long int rather
Guido van Rossumae457142001-08-31 18:31:35 +000033 than raising OverflowError. This is a partial implementation of PEP
34 237. You can use -Wdefault::OverflowWarning to enable a warning for
35 this situation, and -Werror::OverflowWarning to revert to the old
36 OverflowError exception.
37
Guido van Rossum61c345f2001-09-04 03:26:15 +000038- A new command line option, -Q<arg>, is added to control run-time
Guido van Rossumae457142001-08-31 18:31:35 +000039 warnings for the use of classic division. (See PEP 238.) Possible
Guido van Rossum61c345f2001-09-04 03:26:15 +000040 values are -Qold, -Qwarn, and -Qnew. The default is -Qold, meaning
Guido van Rossumae457142001-08-31 18:31:35 +000041 the / operator has its classic meaning and no warnings are issued.
Guido van Rossum61c345f2001-09-04 03:26:15 +000042 Using -Qwarn issues a run-time warning about all uses of classic
43 division for int, long, float and complex arguments. Using -Qnew is
Guido van Rossumae457142001-08-31 18:31:35 +000044 questionable; it turns on new division by default, but only in the
Guido van Rossum61c345f2001-09-04 03:26:15 +000045 __main__ module. You can usefully combine -Qwarn and -Qnew: this
Guido van Rossumae457142001-08-31 18:31:35 +000046 gives the __main__ module new division, and warns about classic
47 division everywhere else.
48
Tim Petersbdee63f2001-09-02 03:40:59 +000049- Many built-in types can now be subclassed. This applies to int,
Guido van Rossumae457142001-08-31 18:31:35 +000050 long, float, str, unicode, and tuple. (The types complex, list and
51 dictionary can also be subclassed; this was introduced earlier.)
52 Note that restrictions apply when subclassing immutable built-in
53 types: you can only affect the value of the instance by overloading
54 __new__. You can add mutable attributes, and the subclass instances
55 will have a __dict__ attribute, but you cannot change the "value"
56 (as implemented by the base class) of an immutable subclass instance
57 once it is created.
58
Guido van Rossumaaf80c82001-09-02 13:44:35 +000059- The dictionary constructor now takes an optional argument, a
60 mapping-like object, and initializes the dictionary from its
61 (key, value) pairs.
62
Tim Petersbdee63f2001-09-02 03:40:59 +000063- A new built-in type, super, has been added. This facilitates making
Guido van Rossumae457142001-08-31 18:31:35 +000064 "cooperative super calls" in a multiple inheritance setting. For an
65 explanation, see http://www.python.org/2.2/descrintro.html#cooperation
66
Tim Petersbdee63f2001-09-02 03:40:59 +000067- A new built-in type, getset, has been added. This enables the
Guido van Rossumae457142001-08-31 18:31:35 +000068 creation of "computed attributes". Such attributes are implemented
69 by getter and setter functions (or only one of these for read-only
70 or write-only attributes), without the need to override
71 __getattr__. See http://www.python.org/2.2/descrintro.html#getset
72
Tim Petersbdee63f2001-09-02 03:40:59 +000073- The syntax of floating-point and imaginary literals has been
Tim Petersd507dab2001-08-30 20:51:59 +000074 liberalized, to allow leading zeroes. Examples of literals now
75 legal that were SyntaxErrors before:
76
77 00.0 0e3 0100j 07.5 00000000000000000008.
78
Tim Petersbdee63f2001-09-02 03:40:59 +000079- An old tokenizer bug allowed floating point literals with an incomplete
Tim Petersc6d95812001-08-28 20:56:27 +000080 exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
81
Tim Petersedc99312001-08-22 21:36:50 +000082Library
83
Martin v. Löwiscb227c92001-09-06 08:54:16 +000084- telnetlib includes symbolic names for the options, and support for
85 setting an option negotiation callback.
86
Tim Petersa40c7932001-09-05 22:36:56 +000087- The new C standard no longer requires that math libraries set errno to
88 ERANGE on overflow. For platform libraries that exploit this new
89 freedom, Python's overflow-checking was wholly broken. A new overflow-
90 checking scheme attempts to repair that, but may not be reliable on all
91 platforms (C doesn't seem to provide anything both useful and portable
92 in this area anymore).
93
Martin v. Löwis44f86962001-09-05 13:44:54 +000094- Asynchronous timeout actions are available through the new class
95 threading.Timer.
96
Tim Peters78526162001-09-05 00:53:45 +000097- math.log and math.log10 now return sensible results for even huge
98 long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
99
Tim Petersbdee63f2001-09-02 03:40:59 +0000100- A new function, imp.lock_held(), returns 1 when the import lock is
Tim Peters69232342001-08-30 05:16:13 +0000101 currently held. See the docs for the imp module.
102
Tim Petersbdee63f2001-09-02 03:40:59 +0000103- pickle, cPickle and marshal on 32-bit platforms can now correctly read
Tim Peters82112372001-08-29 02:28:42 +0000104 dumps containing ints written on platforms where Python ints are 8 bytes.
105 When read on a box where Python ints are 4 bytes, such values are
106 converted to Python longs.
107
Tim Petersbdee63f2001-09-02 03:40:59 +0000108- In restricted execution mode (using the rexec module), unmarshalling
Guido van Rossumae457142001-08-31 18:31:35 +0000109 code objects is no longer allowed. This plugs a security hole.
110
Tim Petersedc99312001-08-22 21:36:50 +0000111Tools
112
113Build
114
Tim Peters7eea37e2001-09-04 22:08:56 +0000115C API
116
117- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
Tim Peters69232342001-08-30 05:16:13 +0000118
Tim Peters9fffa3e2001-09-04 05:14:19 +0000119- Note that PyLong_AsDouble can fail! This has always been true, but no
120 callers checked for it. It's more likely to fail now, because overflow
121 errors are properly detected now. The proper way to check:
122
123 double x = PyLong_AsDouble(some_long_object);
124 if (x == -1.0 && PyErr_Occurred()) {
125 /* The conversion failed. */
126 }
127
Tim Petersbdee63f2001-09-02 03:40:59 +0000128- The GC API has been changed. Extensions that use the old API will still
Neil Schemenauer4042c692001-08-30 15:38:01 +0000129 compile but will not participate in GC. To upgrade an extension
130 module:
131
132 - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
Tim Petersd507dab2001-08-30 20:51:59 +0000133
Neil Schemenauer4042c692001-08-30 15:38:01 +0000134 - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
135 PyObject_GC_Del to deallocate them
Tim Petersd507dab2001-08-30 20:51:59 +0000136
Neil Schemenauer4042c692001-08-30 15:38:01 +0000137 - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
138 to PyObject_GC_UnTrack
Tim Petersd507dab2001-08-30 20:51:59 +0000139
Neil Schemenauer4042c692001-08-30 15:38:01 +0000140 - remove PyGC_HEAD_SIZE from object size calculations
141
142 - remove calls to PyObject_AS_GC and PyObject_FROM_GC
143
Tim Petersbdee63f2001-09-02 03:40:59 +0000144- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
Guido van Rossumae457142001-08-31 18:31:35 +0000145 These can be used safely to construct string objects from a
146 sprintf-style format string (similar to the format string supported
147 by PyErr_Format()).
Tim Peters69232342001-08-30 05:16:13 +0000148
Tim Petersedc99312001-08-22 21:36:50 +0000149New platforms
150
Tim Petersb7da0902001-09-02 23:01:43 +0000151- Stephen Hansen contributed patches sufficient to get a clean compile
152 under Borland C (Windows), but he reports problems running it and ran
153 out of time to complete the port. Volunteers? Expect a MemoryError
154 when importing the types module; this is probably shallow, and
155 causing later failures too.
Tim Petersbdee63f2001-09-02 03:40:59 +0000156
Tim Petersedc99312001-08-22 21:36:50 +0000157Tests
158
159Windows
160
Tim Peters6e13a562001-09-06 00:32:15 +0000161- Large file support is now enabled on Win32 platforms as well as on
162 Win64. This means that, for example, you can use f.tell() and f.seek()
163 to manipulate files larger than 2 gigabytes (provided you have enough
164 disk space, and are using a Windows filesystem that supports large
165 partitions).
166
Tim Petersbdee63f2001-09-02 03:40:59 +0000167- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
Tim Peters402d5982001-08-27 06:37:48 +0000168 points to command.com (patch from Brian Quinlan).
169
Tim Petersedc99312001-08-22 21:36:50 +0000170
Tim Peters20f51a72001-07-21 02:31:40 +0000171What's New in Python 2.2a2?
172===========================
173
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000174Build
175
Barry Warsaw18b2ecf2001-08-22 20:26:56 +0000176- Tim Peters developed a brand new Windows installer using Wise 8.1,
177 generously donated to us by Wise Solutions.
178
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000179- configure supports a new option --enable-unicode, with the values
180 ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
181 type and supporting code is completely removed from the interpreter.
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000182
Jack Jansen32ce0cd2001-08-21 19:28:20 +0000183- A new configure option --enable-framework builds a Mac OS X framework,
184 which "make frameworkinstall" will install. This provides a starting
185 point for more mac-like functionality, join pythonmac-sig@python.org
186 if you are interested in helping.
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000187
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000188- The NeXT platform is no longer supported.
189
190- The `new' module is now statically linked.
191
Tim Peters0afb6092001-08-15 06:06:44 +0000192Tools
193
194- The new Tools/scripts/cleanfuture.py can be used to automatically
Andrew M. Kuchlingb0532092001-08-15 15:54:56 +0000195 edit out obsolete future statements from Python source code. See
Tim Peters0afb6092001-08-15 06:06:44 +0000196 the module docstring for details.
197
Tim Peters20f51a72001-07-21 02:31:40 +0000198Tests
199
Tim Peters5e824c32001-08-12 22:25:01 +0000200- regrtest.py now knows which tests are expected to be skipped on some
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000201 platforms, allowing to give clearer test result output. regrtest
202 also has optional --use/-u switch to run normally disabled tests
203 which require network access or consume significant disk resources.
Tim Peters5e824c32001-08-12 22:25:01 +0000204
Tim Peters20f51a72001-07-21 02:31:40 +0000205- Several new tests in the standard test suite, with special thanks to
206 Nick Mathewson.
207
208Core
209
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000210- The floor division operator // has been added as outlined in PEP
211 238. The / operator still provides classic division (and will until
212 Python 3.0) unless "from __future__ import division" is included, in
213 which case the / operator will provide true division. The operator
214 module provides truediv() and floordiv() functions. Augmented
215 assignment variants are included, as are the equivalent overloadable
216 methods and C API methods. See the PEP for a full discussion:
217 <http://python.sf.net/peps/pep-0238.html>
218
Tim Peters6cd6a822001-08-17 22:11:27 +0000219- Future statements are now effective in simulated interactive shells
220 (like IDLE). This should "just work" by magic, but read Michael
221 Hudson's "Future statements in simulated shells" PEP 264 for full
222 details: <http://python.sf.net/peps/pep-0264.html>.
223
Guido van Rossumf86ddd22001-08-17 21:21:04 +0000224- The type/class unification (PEP 252-253) was integrated into the
225 trunk and is not so tentative any more (the exact specification of
226 some features is still tentative). A lot of work has done on fixing
227 bugs and adding robustness and features (performance still has to
228 come a long way).
229
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000230- Warnings about a mismatch in the Python API during extension import
231 now use the Python warning framework (which makes it possible to
232 write filters for these warnings).
233
Barry Warsaw9b3be7f2001-08-14 18:35:02 +0000234- A function's __dict__ (aka func_dict) will now always be a
235 dictionary. It used to be possible to delete it or set it to None,
236 but now both actions raise TypeErrors. It is still legal to set it
237 to a dictionary object. Getting func.__dict__ before any attributes
238 have been assigned now returns an empty dictionary instead of None.
239
Guido van Rossum32aa5d22001-09-05 18:43:35 +0000240- A new command line option, -E, was added which disables the use of
241 all environment variables, or at least those that are specifically
242 significant to Python. Usually those have a name starting with
243 "PYTHON". This was used to fix a problem where the tests fail if
244 the user happens to have PYTHONHOME or PYTHONPATH pointing to an
245 older distribution.
246
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000247Library
248
Tim Peters5e824c32001-08-12 22:25:01 +0000249- New class Differ and new functions ndiff() and restore() in difflib.py.
250 These package the algorithms used by the popular Tools/scripts/ndiff.py,
Tim Peters0afb6092001-08-15 06:06:44 +0000251 for programmatic reuse.
Tim Peters5e824c32001-08-12 22:25:01 +0000252
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000253- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
254 value using the minimal quoting required for the value; more
255 reliable than using xml.sax.saxutils.escape() for attribute values.
256
257- Readline completion support for cmd.Cmd was added.
258
Barry Warsaw6f3410d2001-08-22 04:08:41 +0000259- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
260
261- Added function threading.BoundedSemaphore()
262
263- Added Ka-Ping Yee's cgitb.py module.
264
265- The `new' module now exposes the CO_xxx flags.
266
Marc-André Lemburgd6277912001-07-31 14:42:42 +0000267New platforms
268
269C API
270
Marc-André Lemburg888fac02001-07-31 14:24:31 +0000271- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
272 which provide a cross-platform implementations for the
273 relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
274 the standard sprintf() and vsprintf() C lib APIs, these versions
275 apply bounds checking on the used buffer which enhances protection
276 against buffer overruns.
277
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000278- Unicode APIs now use name mangling to assure that mixing interpreters
Tim Petersc1731372001-08-04 08:12:36 +0000279 and extensions using different Unicode widths is rendered next to
280 impossible. Trying to import an incompatible Unicode-aware extension
Marc-André Lemburg48dbfe92001-07-31 14:37:40 +0000281 will result in an ImportError. Unicode extensions writers must make
282 sure to check the Unicode width compatibility in their extensions by
283 using at least one of the mangled Unicode APIs in the extension.
284
Martin v. Löwis339d0f72001-08-17 18:39:25 +0000285- Two new flags METH_NOARGS and METH_O are available in method definition
286 tables to simplify implementation of methods with no arguments and a
287 single untyped argument. Calling such methods is more efficient than
288 calling corresponding METH_VARARGS methods. METH_OLDARGS is now
289 deprecated.
290
Tim Petersc1731372001-08-04 08:12:36 +0000291Windows
292
293- "import module" now compiles module.pyw if it exists and nothing else
294 relevant is found.
295
Tim Peters20f51a72001-07-21 02:31:40 +0000296
Guido van Rossum55a78992001-07-17 17:22:32 +0000297What's New in Python 2.2a1?
Tim Petersf553f892001-05-01 20:45:31 +0000298===========================
299
300Core
Tim Petersa814db52001-05-14 07:05:58 +0000301
Tim Peters6d6c1a32001-08-02 04:15:00 +0000302- TENTATIVELY, a large amount of code implementing much of what's
303 described in PEP 252 (Making Types Look More Like Classes) and PEP
304 253 (Subtyping Built-in Types) was added. This will be released
305 with Python 2.2a1. Documentation will be provided separately
306 through http://www.python.org/2.2/. The purpose of releasing this
307 with Python 2.2a1 is to test backwards compatibility. It is
308 possible, though not likely, that a decision is made not to release
309 this code as part of 2.2 final, if any serious backwards
310 incompapatibilities are found during alpha testing that cannot be
311 repaired.
312
Guido van Rossum55a78992001-07-17 17:22:32 +0000313- Generators were added; this is a new way to create an iterator (see
Tim Peters11a0d102001-07-17 18:48:00 +0000314 below) using what looks like a simple function containing one or
Guido van Rossum55a78992001-07-17 17:22:32 +0000315 more 'yield' statements. See PEP 255. Since this adds a new
316 keyword to the language, this feature must be enabled by including a
317 future statement: "from __future__ import generators" (see PEP 236).
318 Generators will become a standard feature in a future release
319 (probably 2.3). Without this future statement, 'yield' remains an
320 ordinary identifier, but a warning is issued each time it is used.
321 (These warnings currently don't conform to the warnings framework of
322 PEP 230; we intend to fix this in 2.2a2.)
323
Marc-André Lemburg12e74b32001-05-22 08:58:23 +0000324- The UTF-16 codec was modified to be more RFC compliant. It will now
325 only remove BOM characters at the start of the string and then
326 only if running in native mode (UTF-16-LE and -BE won't remove a
327 leading BMO character).
328
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000329- Strings now have a new method .decode() to complement the already
330 existing .encode() method. These two methods provide direct access
331 to the corresponding decoders and encoders of the registered codecs.
332
333 To enhance the usability of the .encode() method, the special
334 casing of Unicode object return values was dropped (Unicode objects
335 were auto-magically converted to string using the default encoding).
Tim Peterseb28ef22001-06-02 05:27:19 +0000336
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000337 Both methods will now return whatever the codec in charge of the
338 requested encoding returns as object, e.g. Unicode codecs will
339 return Unicode objects when decoding is requested ("äöü".decode("latin-1")
340 will return u"äöü"). This enables codec writer to create codecs
341 for various simple to use conversions.
342
343 New codecs were added to demonstrate these new features (the .encode()
344 and .decode() columns indicate the type of the returned objects):
345
346 Name | .encode() | .decode() | Description
347 ----------------------------------------------------------------------
348 uu | string | string | UU codec (e.g. for email)
349 base64 | string | string | base64 codec
Guido van Rossumc3415802001-06-06 13:30:54 +0000350 quopri | string | string | quoted-printable codec
Marc-André Lemburgfab96cc2001-05-15 18:38:45 +0000351 zlib | string | string | zlib compression
352 hex | string | string | 2-byte hex codec
353 rot-13 | string | Unicode | ROT-13 Unicode charmap codec
354
Mark Hammond2a0af792001-05-14 03:09:36 +0000355- Some operating systems now support the concept of a default Unicode
356 encoding for file system operations. Notably, Windows supports 'mbcs'
357 as the default. The Macintosh will also adopt this concept in the medium
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000358 term, although the default encoding for that platform will be other than
Mark Hammond2a0af792001-05-14 03:09:36 +0000359 'mbcs'.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000360
361 On operating system that support non-ASCII filenames, it is common for
Mark Hammond2a0af792001-05-14 03:09:36 +0000362 functions that return filenames (such as os.listdir()) to return Python
363 string objects pre-encoded using the default file system encoding for
364 the platform. As this encoding is likely to be different from Python's
365 default encoding, converting this name to a Unicode object before passing
366 it back to the Operating System would result in a Unicode error, as Python
Tim Petersa814db52001-05-14 07:05:58 +0000367 would attempt to use its default encoding (generally ASCII) rather than
368 the default encoding for the file system.
Guido van Rossum1bd797a2001-05-14 13:53:38 +0000369
Tim Petersa814db52001-05-14 07:05:58 +0000370 In general, this change simply removes surprises when working with
371 Unicode and the file system, making these operations work as you expect,
372 increasing the transparency of Unicode objects in this context.
Mark Hammond2a0af792001-05-14 03:09:36 +0000373 See [????] for more details, including examples.
Tim Petersf553f892001-05-01 20:45:31 +0000374
Tim Peters61dff2b2001-05-08 15:43:37 +0000375- Float (and complex) literals in source code were evaluated to full
376 precision only when running from a .py file; the same code loaded from a
377 .pyc (or .pyo) file could suffer numeric differences starting at about the
378 12th significant decimal digit. For example, on a machine with IEEE-754
379 floating arithmetic,
380
381 x = 9007199254740992.0
382 print long(x)
383
384 printed 9007199254740992 if run directly from .py, but 9007199254740000
385 if from a compiled (.pyc or .pyo) file. This was due to marshal using
386 str(float) instead of repr(float) when building code objects. marshal
387 now uses repr(float) instead, which should reproduce floats to full
388 machine precision (assuming the platform C float<->string I/O conversion
389 functions are of good quality).
390
391 This may cause floating-point results to change in some cases, and
392 usually for the better, but may also cause numerically unstable
393 algorithms to break.
394
Tim Peters2f228e72001-05-13 00:19:31 +0000395- The implementation of dicts suffers fewer collisions, which has speed
396 benefits. However, the order in which dict entries appear in dict.keys(),
397 dict.values() and dict.items() may differ from previous releases for a
398 given dict. Nothing is defined about this order, so no program should
399 rely on it. Nevertheless, it's easy to write test cases that rely on the
400 order by accident, typically because of printing the str() or repr() of a
401 dict to an "expected results" file. See Lib/test/test_support.py's new
402 sortdict(dict) function for a simple way to display a dict in sorted
403 order.
404
Tim Peters7a3bfc32001-06-12 01:22:22 +0000405- Many other small changes to dicts were made, resulting in faster
406 operation along the most common code paths.
407
Guido van Rossum10315822001-05-01 20:54:30 +0000408- Dictionary objects now support the "in" operator: "x in dict" means
409 the same as dict.has_key(x).
410
Barry Warsaw51acc8d2001-06-26 20:12:50 +0000411- The update() method of dictionaries now accepts generic mapping
412 objects. Specifically the argument object must support the .keys()
413 and __getitem__() methods. This allows you to say, for example,
414 {}.update(UserDict())
415
Guido van Rossum10315822001-05-01 20:54:30 +0000416- Iterators were added; this is a generalized way of providing values
417 to a for loop. See PEP 234. There's a new built-in function iter()
418 to return an iterator. There's a new protocol to get the next value
419 from an iterator using the next() method (in Python) or the
420 tp_iternext slot (in C). There's a new protocol to get iterators
421 using the __iter__() method (in Python) or the tp_iter slot (in C).
422 Iterating (i.e. a for loop) over a dictionary generates its keys.
423 Iterating over a file generates its lines.
424
Tim Petersf553f892001-05-01 20:45:31 +0000425- The following functions were generalized to work nicely with iterator
426 arguments:
Tim Peterse63415e2001-05-08 04:38:29 +0000427 map(), filter(), reduce(), zip()
Tim Peters8572b4f2001-05-06 01:05:02 +0000428 list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
429 max(), min()
Tim Peters1af03e92001-05-26 19:37:54 +0000430 join() method of strings
431 extend() method of lists
Tim Peters75f8e352001-05-05 11:33:43 +0000432 'x in y' and 'x not in y' (PySequence_Contains() in C API)
433 operator.countOf() (PySequence_Count() in C API)
Tim Petersd6d010b2001-06-21 02:49:55 +0000434 right-hand side of assignment statements with multiple targets, such as
435 x, y, z = some_iterable_object_returning_exactly_3_values
Tim Peters75f8e352001-05-05 11:33:43 +0000436
Tim Petersd85e1022001-05-11 21:51:48 +0000437- Accessing module attributes is significantly faster (for example,
438 random.random or os.path or yourPythonModule.yourAttribute).
439
Tim Peterse63415e2001-05-08 04:38:29 +0000440- Comparing dictionary objects via == and != is faster, and now works even
441 if the keys and values don't support comparisons other than ==.
442
Tim Peters95bf9392001-05-10 08:32:44 +0000443- Comparing dictionaries in ways other than == and != is slower: there were
444 insecurities in the dict comparison implementation that could cause Python
445 to crash if the element comparison routines for the dict keys and/or
446 values mutated the dicts. Making the code bulletproof slowed it down.
447
Tim Peterseb28ef22001-06-02 05:27:19 +0000448- Collisions in dicts are resolved via a new approach, which can help
449 dramatically in bad cases. For example, looking up every key in a dict
Tim Peters7a3bfc32001-06-12 01:22:22 +0000450 d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
Tim Peterseb28ef22001-06-02 05:27:19 +0000451 faster now. Thanks to Christian Tismer for pointing out the cause and
452 the nature of an effective cure (last December! better late than never).
Tim Peters15d49292001-05-27 07:39:22 +0000453
Tim Peters52e155e2001-06-16 05:42:57 +0000454- repr() is much faster for large containers (dict, list, tuple).
455
456
Tim Petersa814db52001-05-14 07:05:58 +0000457Library
458
Fred Drake960fdf92001-07-20 18:38:26 +0000459- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
460 were added to the string module. These a locale-indenpendent
461 constants, unlike letters, lowercase, and uppercase. These are now
462 use in appropriate locations in the standard library.
463
Martin v. Löwisf0473d52001-07-18 16:17:16 +0000464- The flags used in dlopen calls can now be configured using
465 sys.setdlopenflags and queried using sys.getdlopenflags.
466
Guido van Rossumc7e4aca2001-07-12 11:54:37 +0000467- Fredrik Lundh's xmlrpclib is now a standard library module. This
468 provides full client-side XML-RPC support. In addition,
469 Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
470 one asyncore-based). Thanks to Eric Raymond for the documentation.
471
Guido van Rossum643d3912001-07-05 14:46:25 +0000472- The xrange() object is simplified: it no longer supports slicing,
473 repetition, comparisons, efficient 'in' checking, the tolist()
474 method, or the start, stop and step attributes. See PEP 260.
475
Martin v. Löwisebf94db2001-06-06 06:25:40 +0000476- A new function fnmatch.filter to filter lists of file names was added.
477
Barry Warsawffd674d2001-05-22 16:00:10 +0000478- calendar.py uses month and day names based on the current locale.
479
Guido van Rossum2e0a6542001-05-15 02:14:44 +0000480- strop is now *really* obsolete (this was announced before with 1.6),
481 and issues DeprecationWarning when used (except for the four items
482 that are still imported into string.py).
483
Tim Petersa814db52001-05-14 07:05:58 +0000484- Cookie.py now sorts key+value pairs by key in output strings.
485
486- pprint.isrecursive(object) didn't correctly identify recursive objects.
487 Now it does.
488
Tim Peters95b3f782001-05-14 18:39:41 +0000489- pprint functions now much faster for large containers (tuple, list, dict).
490
Tim Peters7b9542a2001-06-10 23:40:19 +0000491- New 'q' and 'Q' format codes in the struct module, corresponding to C
492 types "long long" and "unsigned long long" (on Windows, __int64). In
493 native mode, these can be used only when the platform C compiler supports
494 these types (when HAVE_LONG_LONG is #define'd by the Python config
495 process), and then they inherit the sizes and alignments of the C types.
Tim Peters7a3bfc32001-06-12 01:22:22 +0000496 In standard mode, 'q' and 'Q' are supported on all platforms, and are
497 8-byte integral types.
Tim Peters7b9542a2001-06-10 23:40:19 +0000498
Guido van Rossum83213cc2001-06-12 16:48:52 +0000499- The site module installs a new built-in function 'help' that invokes
500 pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
501 it displays a message reminding the user to use 'help()' or
502 'help(object)'.
503
Tim Petersa814db52001-05-14 07:05:58 +0000504Tests
505
506- New test_mutants.py runs dict comparisons where the key and value
507 comparison operators mutute the dicts randomly during comparison. This
508 rapidly causes Python to crash under earlier releases (not for the faint
509 of heart: it can also cause Win9x to freeze or reboot!).
510
511- New test_pprint.py verfies that pprint.isrecursive() and
Tim Peters95b3f782001-05-14 18:39:41 +0000512 pprint.isreadable() return sensible results. Also verifies that simple
513 cases produce correct output.
Tim Petersa814db52001-05-14 07:05:58 +0000514
Tim Peters4324aa32001-05-28 22:30:08 +0000515C API
516
517- Removed the unused last_is_sticky argument from the internal
518 _PyTuple_Resize(). If this affects you, you were cheating.
519
520
Guido van Rossum55a78992001-07-17 17:22:32 +0000521======================================================================
522
523
Guido van Rossumffe13be2001-04-16 18:46:45 +0000524What's New in Python 2.1 (final)?
525=================================
526
527We only changed a few things since the last release candidate, all in
528Python library code:
529
530- A bug in the locale module was fixed that affected locales which
531 define no grouping for numeric formatting.
532
533- A few bugs in the weakref module's implementations of weak
534 dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
535 and the test suite was updated to check for these bugs.
536
537- An old bug in the os.path.walk() function (introduced in Python
538 2.0!) was fixed: a non-existent file would cause an exception
539 instead of being ignored.
540
541- Fixed a few bugs in the new symtable module found by Neil Norwitz's
542 PyChecker.
543
544
Guido van Rossum5b08f132001-04-16 02:05:23 +0000545What's New in Python 2.1c2?
546===========================
Barry Warsaw11e89c72001-04-11 20:37:57 +0000547
Guido van Rossum5b08f132001-04-16 02:05:23 +0000548A flurry of small changes, and one showstopper fixed in the nick of
549time made it necessary to release another release candidate. The list
550here is the *complete* list of patches (except version updates):
Guido van Rossum4fb60362001-04-13 00:46:14 +0000551
Guido van Rossum5b08f132001-04-16 02:05:23 +0000552Core
Guido van Rossum4fb60362001-04-13 00:46:14 +0000553
Guido van Rossum5b08f132001-04-16 02:05:23 +0000554- Tim discovered a nasty bug in the dictionary code, caused by
555 PyDict_Next() calling dict_resize(), and the GC code's use of
556 PyDict_Next() violating an assumption in dict_items(). This was
557 fixed with considerable amounts of band-aid, but the net effect is a
558 saner and more robust implementation.
559
560- Made a bunch of symbols static that were accidentally global.
561
562Build and Ports
563
564- The setup.py script didn't check for a new enough version of zlib
565 (1.1.3 is needed). Now it does.
566
567- Changed "make clean" target to also remove shared libraries.
568
569- Added a more general warning about the SGI Irix optimizer to README.
570
571Library
572
573- Fix a bug in urllib.basejoin("http://host", "../file.html") which
574 omitted the slash between host and file.html.
575
576- The mailbox module's _Mailbox class contained a completely broken
577 and undocumented seek() method. Ripped it out.
578
579- Fixed a bunch of typos in various library modules (urllib2, smtpd,
580 sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
581
582- Fixed a few last-minute bugs in unittest.
583
584Extensions
585
586- Reverted the patch to the OpenSSL code in socketmodule.c to support
587 RAND_status() and the EGD, and the subsequent patch that tried to
588 fix it for pre-0.9.5 versions; the problem with the patch is that on
589 some systems it issues a warning whenever socket is imported, and
590 that's unacceptable.
591
592Tests
593
594- Fixed the pickle tests to work with "import test.test_pickle".
595
596- Tweaked test_locale.py to actually run the test Windows.
597
598- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
599 not "wb" (which is not a valid mode at all).
600
601- Fix pstats browser crashes. Import readline if it exists to make
602 the user interface nicer.
603
604- Add "import thread" to the top of test modules that import the
605 threading module (test_asynchat and test_threadedtempfile). This
606 prevents test failures caused by a broken threading module resulting
607 from a previously caught failed import.
608
609- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
610 needed on some platforms (e.g. Solaris 8) when the tests are run
611 twice in succession.
612
613- Skip rather than fail test_sunaudiodev if no audio device is found.
614
615
616What's New in Python 2.1c1?
617===========================
618
619This list was significantly updated when 2.1c2 was released; the 2.1c1
620release didn't mention most changes that were actually part of 2.1c1:
621
622Legal
623
624- Copyright was assigned to the Python Software Foundation (PSF) and a
625 PSF license (very similar to the CNRI license) was added.
626
627- The CNRI copyright notice was updated to include 2001.
628
629Core
Barry Warsaw11e89c72001-04-11 20:37:57 +0000630
Guido van Rossumc9932722001-04-12 02:31:27 +0000631- After a public outcry, assignment to __debug__ is no longer illegal;
632 instead, a warning is issued. It will become illegal in 2.2.
633
Guido van Rossum5b08f132001-04-16 02:05:23 +0000634- Fixed a core dump with "%#x" % 0, and changed the semantics so that
635 "%#x" now always prepends "0x", even if the value is zero.
636
637- Fixed some nits in the bytecode compiler.
638
639- Fixed core dumps when calling certain kinds of non-functions.
640
641- Fixed various core dumps caused by reference count bugs.
642
643Build and Ports
644
645- Use INSTALL_SCRIPT to install script files.
646
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000647- New port: SCO Unixware 7, by Billy G. Allie.
648
Guido van Rossum5b08f132001-04-16 02:05:23 +0000649- Updated RISCOS port.
650
651- Updated BeOS port and notes.
652
653- Various other porting problems resolved.
654
655Library
656
657- The TERMIOS and SOCKET modules are now truly obsolete and
658 unnecessary. Their symbols are incorporated in the termios and
659 socket modules.
660
661- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
662 better tests for pickling.
663
664- threading: make Condition.wait() robust against KeyboardInterrupt.
665
666- zipfile: add support to zipfile to support opening an archive
667 represented by an open file rather than a file name. Fix bug where
668 the archive was not properly closed. Fixed a bug in this bugfix
669 where flush() was called for a read-only file.
670
671- imputil: added an uninstall() method to the ImportManager.
672
673- Canvas: fixed bugs in lower() and tkraise() methods.
674
675- SocketServer: API change (added overridable close_request() method)
676 so that the TCP server can explicitly close the request.
677
678- pstats: Eric Raymond added a simple interactive statistics browser,
679 invoked when the module is run as a script.
680
681- locale: fixed a problem in format().
682
683- webbrowser: made it work when the BROWSER environment variable has a
684 value like "/usr/bin/netscape". Made it auto-detect Konqueror for
685 KDE 2. Fixed some other nits.
686
687- unittest: changes to allow using a different exception than
688 AssertionError, and added a few more function aliases. Some other
689 small changes.
690
691- urllib, urllib2: fixed redirect problems and a coupleof other nits.
692
693- asynchat: fixed a critical bug in asynchat that slipped through the
694 2.1b2 release. Fixed another rare bug.
695
696- Fix some unqualified except: clauses (always a bad code example).
697
698XML
699
700- pyexpat: new API get_version_string().
701
702- Fixed some minidom bugs.
703
704Extensions
705
706- Fixed a core dump in _weakref. Removed the weakref.mapping()
707 function (it adds nothing to the API).
708
709- Rationalized the use of header files in the readline module, to make
710 it compile (albeit with some warnings) with the very recent readline
711 4.2, without breaking for earlier versions.
712
713- Hopefully fixed a buffering problem in linuxaudiodev.
714
715- Attempted a fix to make the OpenSSL support in the socket module
716 work again with pre-0.9.5 versions of OpenSSL.
717
718Tests
719
720- Added a test case for asynchat and asyncore.
721
722- Removed coupling between tests where one test failing could break
723 another.
724
725Tools
726
727- Ping added an interactive help browser to pydoc, fixed some nits
728 in the rest of the pydoc code, and added some features to his
729 inspect module.
730
731- An updated python-mode.el version 4.1 which integrates Ken
732 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
733 much nicer in XEmacs and Emacs. When stepping through your program
734 with pdb, in either the shell window or the *Python* window, the
735 source file and line will be tracked by an arrow. Very cool!
736
737- IDLE: syntax warnings in interactive mode are changed into errors.
738
739- Some improvements to Tools/webchecker (ignore some more URL types,
Tim Peters0e57abf2001-05-02 07:39:38 +0000740 follow some more links).
Guido van Rossum5b08f132001-04-16 02:05:23 +0000741
742- Brought the Tools/compiler package up to date.
Guido van Rossum34d37dc2001-04-11 21:03:32 +0000743
Barry Warsaw11e89c72001-04-11 20:37:57 +0000744
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000745What's New in Python 2.1 beta 2?
746================================
747
Guido van Rossum053ae352001-03-22 14:17:21 +0000748(Unlisted are many fixed bugs, more documentation, etc.)
749
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000750Core language, builtins, and interpreter
751
Guido van Rossum053ae352001-03-22 14:17:21 +0000752- The nested scopes work (enabled by "from __future__ import
753 nested_scopes") is completed; in particular, the future now extends
754 into code executed through exec, eval() and execfile(), and into the
755 interactive interpreter.
756
757- When calling a base class method (e.g. BaseClass.__init__(self)),
758 this is now allowed even if self is not strictly spoken a class
759 instance (e.g. when using metaclasses or the Don Beaudry hook).
760
761- Slice objects are now comparable but not hashable; this prevents
762 dict[:] from being accepted but meaningless.
763
764- Complex division is now calculated using less braindead algorithms.
765 This doesn't change semantics except it's more likely to give useful
766 results in extreme cases. Complex repr() now uses full precision
767 like float repr().
768
769- sgmllib.py now calls handle_decl() for simple <!...> declarations.
770
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000771- It is illegal to assign to the name __debug__, which is set when the
772 interpreter starts. It is effectively a compile-time constant.
773
774- A warning will be issued if a global statement for a variable
775 follows a use or assignment of that variable.
776
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000777Standard library
778
Guido van Rossum053ae352001-03-22 14:17:21 +0000779- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
780 inspired by JUnit), is now part of the standard library. You now
781 have a choice of two testing frameworks: unittest requires you to
782 write testcases as separate code, doctest gathers them from
783 docstrings. Both approaches have their advantages and
784 disadvantages.
785
786- A new module Tix was added, which wraps the Tix extension library
787 for Tk. With that module, it is not necessary to statically link
788 Tix with _tkinter, since Tix will be loaded with Tcl's "package
789 require" command. See Demo/tix/.
790
791- tzparse.py is now obsolete.
792
793- In gzip.py, the seek() and tell() methods are removed -- they were
794 non-functional anyway, and it's better if callers can test for their
795 existence with hasattr().
796
797Python/C API
798
799- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
800 that's already in the dictionary during a PyDict_Next() iteration.
801 This used to fail occasionally when a dictionary resize operation
802 could be triggered that would rehash all the keys. All other
803 modifications to the dictionary are still off-limits during a
804 PyDict_Next() iteration!
805
806- New extended APIs related to passing compiler variables around.
807
808- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
809 implement isinstance() and issubclass().
810
811- Py_BuildValue() now has a "D" conversion to create a Python complex
812 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +0000813
Fred Drake4e262a92001-03-22 18:26:47 +0000814- Extensions types which support weak references must now set the
815 field allocated for the weak reference machinery to NULL themselves;
816 this is done to avoid the cost of checking each object for having a
817 weakly referencable type in PyObject_INIT(), since most types are
818 not weakly referencable.
819
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000820- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
821 free variables and cell variables to and from the frame's f_locals.
822
823- Variants of several functions defined in pythonrun.h have been added
824 to support the nested_scopes future statement. The variants all end
825 in Flags and take an extra argument, a PyCompilerFlags *; examples:
826 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
827 variants may be removed in Python 2.2, when nested scopes are
Tim Peters0e57abf2001-05-02 07:39:38 +0000828 mandatory.
Jeremy Hyltonf626db72001-03-23 14:18:27 +0000829
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000830Distutils
831
832- the sdist command now writes a PKG-INFO file, as described in PEP 241,
833 into the release tree.
834
Tim Peters0e57abf2001-05-02 07:39:38 +0000835- several enhancements to the bdist_wininst command from Thomas Heller
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000836 (an uninstaller, more customization of the installer's display)
837
838- from Jack Jansen: added Mac-specific code to generate a dialog for
839 users to specify the command-line (because providing a command-line with
Tim Peters0e57abf2001-05-02 07:39:38 +0000840 MacPython is awkward). Jack also made various fixes for the Mac
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000841 and the Metrowerks compiler.
Tim Peters0e57abf2001-05-02 07:39:38 +0000842
843- added 'platforms' and 'keywords' to the set of metadata that can be
844 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000845
846- applied patches from Jason Tishler to make the compiler class work with
847 Cygwin.
848
849
Tim Peters2fe289a2001-03-01 22:19:38 +0000850What's New in Python 2.1 beta 1?
851================================
Tim Petersd66595f2001-02-04 03:09:53 +0000852
853Core language, builtins, and interpreter
854
Guido van Rossum9d0fbde2001-03-02 14:00:32 +0000855- Following an outcry from the community about the amount of code
856 broken by the nested scopes feature introduced in 2.1a2, we decided
857 to make this feature optional, and to wait until Python 2.2 (or at
858 least 6 months) to make it standard. The option can be enabled on a
859 per-module basis by adding "from __future__ import nested_scopes" at
860 the beginning of a module (before any other statements, but after
861 comments and an optional docstring). See PEP 236 (Back to the
862 __future__) for a description of the __future__ statement. PEP 227
863 (Statically Nested Scopes) has been updated to reflect this change,
864 and to clarify the semantics in a number of endcases.
865
866- The nested scopes code, when enabled, has been hardened, and most
867 bugs and memory leaks in it have been fixed.
868
869- Compile-time warnings are now generated for a number of conditions
870 that will break or change in meaning when nested scopes are enabled:
871
872 - Using "from...import *" or "exec" without in-clause in a function
873 scope that also defines a lambda or nested function with one or
874 more free (non-local) variables. The presence of the import* or
875 bare exec makes it impossible for the compiler to determine the
876 exact set of local variables in the outer scope, which makes it
877 impossible to determine the bindings for free variables in the
878 inner scope. To avoid the warning about import *, change it into
879 an import of explicitly name object, or move the import* statement
880 to the global scope; to avoid the warning about bare exec, use
881 exec...in... (a good idea anyway -- there's a possibility that
882 bare exec will be deprecated in the future).
883
884 - Use of a global variable in a nested scope with the same name as a
885 local variable in a surrounding scope. This will change in
886 meaning with nested scopes: the name in the inner scope will
887 reference the variable in the outer scope rather than the global
888 of the same name. To avoid the warning, either rename the outer
889 variable, or use a global statement in the inner function.
890
Neil Schemenauera35c6882001-02-27 04:45:05 +0000891- An optional object allocator has been included. This allocator is
892 optimized for Python objects and should be faster and use less memory
893 than the standard system allocator. It is not enabled by default
894 because of possible thread safety problems. The allocator is only
895 protected by the Python interpreter lock and it is possible that some
896 extension modules require a thread safe allocator. The object
897 allocator can be enabled by providing the "--with-pymalloc" option to
898 configure.
899
Tim Petersd66595f2001-02-04 03:09:53 +0000900Standard library
901
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000902- pyexpat now detects the expat version if expat.h defines it. A
903 number of additional handlers are provided, which are only available
904 since expat 1.95. In addition, the methods SetParamEntityParsing and
905 GetInputContext of Parser objects are available with 1.95.x
906 only. Parser objects now provide the ordered_attributes and
907 specified_attributes attributes. A new module expat.model was added,
908 which offers a number of additional constants if 1.95.x is used.
909
910- xml.dom offers the new functions registerDOMImplementation and
911 getDOMImplementation.
912
913- xml.dom.minidom offers a toprettyxml method. A number of DOM
914 conformance issues have been resolved. In particular, Element now
915 has an hasAttributes method, and the handling of namespaces was
916 improved.
917
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000918- Ka-Ping Yee contributed two new modules: inspect.py, a module for
919 getting information about live Python code, and pydoc.py, a module
920 for interactively converting docstrings to HTML or text.
921 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +0000922 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +0000923 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
924 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000925
Tim Peters1eff7962001-03-01 02:31:33 +0000926- New library module difflib.py, primarily packaging the SequenceMatcher
927 class at the heart of the popular ndiff.py file-comparison tool.
928
929- doctest.py (a framework for verifying Python code examples in docstrings)
930 is now part of the std library.
931
Tim Petersd66595f2001-02-04 03:09:53 +0000932Windows changes
933
Guido van Rossume3955a82001-03-02 14:05:59 +0000934- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
935 small GUI that lets you browse the module docstrings using your
936 default web browser.
937
Tim Peters1eff7962001-03-01 02:31:33 +0000938- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
939 Platforms) is implemented. See
940
941 http://python.sourceforge.net/peps/pep-0235.html
942
943 for full details, especially the "Current Lower-Left Semantics" section.
944 The new Windows import rules are simpler than before:
945
946 A. If the PYTHONCASEOK environment variable exists, same as
947 before: silently accept the first case-insensitive match of any
948 kind; raise ImportError if none found.
949
950 B. Else search sys.path for the first case-sensitive match; raise
951 ImportError if none found.
952
953 The same rules have been implented on other platforms with case-
954 insensitive but case-preserving filesystems too (including Cygwin, and
955 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +0000956
Tim Peters25a9ce32001-02-19 07:06:36 +0000957- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
958 what it's supposed to do (and does do under NT and 2000) via direct
959 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +0000960 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +0000961 all Win9x systems before.
962
Tim Peters1eff7962001-03-01 02:31:33 +0000963- Build: Subproject _test (effectively) renamed to _testcapi.
964
Tim Peters2fe289a2001-03-01 22:19:38 +0000965New platforms
966
967- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
968 Thanks to Steven Majewski!
969
970- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
971 Tishler!
972
Guido van Rossum9089b272001-03-02 06:49:50 +0000973- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
974 Schwertberger! See RISCOS/README for more information -- it seems
975 that because of the bizarre filename conventions on RISCOS, no port
976 to that platform is easy. Note that the new variable os.endsep is
977 silently supported in order to make life easier on this platform,
978 but we don't advertise it because it's not worth for most folks to
979 care about RISCOS portability.
980
Tim Peters25a9ce32001-02-19 07:06:36 +0000981
Tim Petersd7b5e882001-01-25 03:36:26 +0000982What's New in Python 2.1 alpha 2?
983=================================
Tim Peters40ead762001-01-27 05:35:26 +0000984
Tim Petersd7b5e882001-01-25 03:36:26 +0000985Core language, builtins, and interpreter
986
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000987- Scopes nest. If a name is used in a function or class, but is not
988 local, the definition in the nearest enclosing function scope will
989 be used. One consequence of this change is that lambda statements
990 could reference variables in the namespaces where the lambda is
991 defined. In some unusual cases, this change will break code.
992
993 In all previous version of Python, names were resolved in exactly
994 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000995 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000996 function A is defined within a function B, the names bound in B are
997 not visible in A. The new rules make names bound in B visible in A,
998 unless A contains a name binding that hides the binding in B.
999
1000 Section 4.1 of the reference manual describes the new scoping rules
1001 in detail. The test script in Lib/test/test_scope.py demonstrates
1002 some of the effects of the change.
1003
1004 The new rules will cause existing code to break if it defines nested
1005 functions where an outer function has local variables with the same
1006 name as globals or builtins used by the inner function. Example:
1007
1008 def munge(str):
1009 def helper(x):
1010 return str(x)
1011 if type(str) != type(''):
1012 str = helper(str)
1013 return str.strip()
1014
1015 Under the old rules, the name str in helper() is bound to the
1016 builtin function str(). Under the new rules, it will be bound to
1017 the argument named str and an error will occur when helper() is
1018 called.
1019
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001020- The compiler will report a SyntaxError if "from ... import *" occurs
1021 in a function or class scope. The language reference has documented
1022 that this case is illegal, but the compiler never checked for it.
1023 The recent introduction of nested scope makes the meaning of this
1024 form of name binding ambiguous. In a future release, the compiler
1025 may allow this form when there is no possibility of ambiguity.
1026
Tim Peters40ead762001-01-27 05:35:26 +00001027- repr(string) is easier to read, now using hex escapes instead of octal,
1028 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
1029
1030 >>> "\texample \r\n" + chr(0) + chr(255)
1031 '\texample \r\n\x00\xff' # in 2.1
1032 '\011example \015\012\000\377' # in 2.0
1033
Moshe Zadka6af0ce02001-01-29 06:41:00 +00001034- Functions are now compared and hashed by identity, not by value, since
1035 the func_code attribute is writable.
1036
Fred Drakefb9d7122001-02-01 20:00:40 +00001037- Weak references (PEP 205) have been added. This involves a few
1038 changes in the core, an extension module (_weakref), and a Python
1039 module (weakref). The weakref module is the public interface. It
1040 includes support for "explicit" weak references, proxy objects, and
1041 mappings with weakly held values.
1042
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001043- A 'continue' statement can now appear in a try block within the body
1044 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +00001045 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +00001046
Tim Petersd7b5e882001-01-25 03:36:26 +00001047Standard library
1048
Barry Warsaw30dbd142001-01-31 22:14:01 +00001049- mailbox.py now has a new class, PortableUnixMailbox which is
1050 identical to UnixMailbox but uses a more portable scheme for
1051 determining From_ separators. Also, the constructors for all the
1052 classes in this module have a new optional `factory' argument, which
1053 is a callable used when new message classes must be instantiated by
1054 the next() method.
1055
Tim Petersd7b5e882001-01-25 03:36:26 +00001056- random.py is now self-contained, and offers all the functionality of
1057 the now-deprecated whrandom.py. See the docs for details. random.py
1058 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +00001059 and restoring the internal state of the generator; and jumpahead(n),
1060 for quickly forcing the internal state to be the same as if n calls to
1061 random() had been made. The latter is particularly useful for multi-
1062 threaded programs, creating one instance of the random.Random() class for
1063 each thread, then using .jumpahead() to force each instance to use a
1064 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +00001065
Tim Peters0de88fc2001-02-01 04:59:18 +00001066- random.py's seed() function is new. For bit-for-bit compatibility with
1067 prior releases, use the whseed function instead. The new seed function
1068 addresses two problems: (1) The old function couldn't produce more than
1069 about 2**24 distinct internal states; the new one about 2**45 (the best
1070 that can be done in the Wichmann-Hill generator). (2) The old function
1071 sometimes produced identical internal states when passed distinct
1072 integers, and there was no simple way to predict when that would happen;
1073 the new one guarantees to produce distinct internal states for all
1074 arguments in [0, 27814431486576L).
1075
Jeremy Hylton4c4fda02001-02-02 03:29:24 +00001076- The socket module now supports raw packets on Linux. The socket
1077 family is AF_PACKET.
1078
Tim Peters9ea17ac2001-02-02 05:57:15 +00001079- test_capi.py is a start at running tests of the Python C API. The tests
1080 are implemented by the new Modules/_testmodule.c.
1081
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +00001082- A new extension module, _symtable, provides provisional access to the
1083 internal symbol table used by the Python compiler. A higher-level
1084 interface will be added on top of _symtable in a future release.
1085
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +00001086- Removed the obsolete soundex module.
1087
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001088- xml.dom.minidom now uses the standard DOM exceptions. Node supports
1089 the isSameNode method; NamedNodeMap the get method.
1090
1091- xml.sax.expatreader supports the lexical handler property; it
1092 generates comment, startCDATA, and endCDATA events.
1093
Tim Petersee826f82001-01-31 19:39:44 +00001094Windows changes
1095
1096- Build procedure: the zlib project is built in a different way that
1097 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +00001098 the zlib binary used. See PCbuild\readme.txt for details. Your old
1099 zlib-related directories can be deleted; you'll need to download fresh
1100 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +00001101
Tim Peters9ea17ac2001-02-02 05:57:15 +00001102- Build: New subproject _test for the benefit of test_capi.py (see above).
1103
Tim Petersb16c56f2001-02-02 21:24:51 +00001104- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
1105 interface to some Python compiler internals).
1106
1107- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +00001108 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +00001109
Tim Petersa3a3a032000-11-30 05:22:44 +00001110What's New in Python 2.1 alpha 1?
1111=================================
1112
1113Core language, builtins, and interpreter
1114
Marc-André Lemburgebb195b2001-01-20 10:34:52 +00001115- There is a new Unicode companion to the PyObject_Str() API
1116 called PyObject_Unicode(). It behaves in the same way as the
1117 former, but assures that the returned value is an Unicode object
1118 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +00001119
Guido van Rossumf98eda02001-01-17 15:54:45 +00001120- The comparison operators support "rich comparison overloading" (PEP
1121 207). C extension types can provide a rich comparison function in
1122 the new tp_richcompare slot in the type object. The cmp() function
1123 and the C function PyObject_Compare() first try the new rich
1124 comparison operators before trying the old 3-way comparison. There
1125 is also a new C API PyObject_RichCompare() (which also falls back on
1126 the old 3-way comparison, but does not constrain the outcome of the
1127 rich comparison to a Boolean result).
1128
1129 The rich comparison function takes two objects (at least one of
1130 which is guaranteed to have the type that provided the function) and
1131 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
1132 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
1133 object, which may be NotImplemented (in which case the tp_compare
1134 slot function is used as a fallback, if defined).
1135
1136 Classes can overload individual comparison operators by defining one
1137 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +00001138 __ge__. There are no explicit "reflected argument" versions of
1139 these; instead, __lt__ and __gt__ are each other's reflection,
1140 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
1141 reflection (similar at the C level). No other implications are
1142 made; in particular, Python does not assume that == is the Boolean
1143 inverse of !=, or that < is the Boolean inverse of >=. This makes
1144 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +00001145
1146 Classes or types that want to implement (in)equality tests but not
1147 the ordering operators (i.e. unordered types) should implement ==
1148 and !=, and raise an error for the ordering operators.
1149
Guido van Rossuma88479f2001-01-18 14:28:08 +00001150 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +00001151 Boolean; e.g. a matrix type might want to return a matrix of bits
1152 for A < B, giving elementwise comparisons. Such types should ensure
1153 that any interpretation of their value in a Boolean context raises
1154 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
1155 at the C level) to always raise an exception.
1156
Guido van Rossuma88479f2001-01-18 14:28:08 +00001157- Complex numbers use rich comparisons to define == and != but raise
1158 an exception for <, <=, > and >=. Unfortunately, this also means
1159 that cmp() of two complex numbers raises an exception when the two
1160 numbers differ. Since it is not mathematically meaningful to compare
1161 complex numbers except for equality, I hope that this doesn't break
1162 too much code.
1163
Tim Peters3389f192001-02-18 08:48:49 +00001164- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +00001165 not defined by the language, other than that it's arbitrary but
1166 consistent (see the Reference Manual). An implementation detail changed
1167 in 2.1a1 such that None now compares less than any other object. Code
1168 relying on this new behavior (like code that relied on the previous
1169 behavior) does so at its own risk.
1170
Barry Warsaw573b5412001-01-15 20:43:18 +00001171- Functions and methods now support getting and setting arbitrarily
1172 named attributes (PEP 232). Functions have a new __dict__
1173 (a.k.a. func_dict) which hold the function attributes. Methods get
1174 and set attributes on their underlying im_func. It is a TypeError
1175 to set an attribute on a bound method.
1176
Guido van Rossum051e3352001-01-15 19:11:10 +00001177- The xrange() object implementation has been improved so that
1178 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
1179 limitation that in this case len(xrange(sys.maxint)) can't be
1180 calculated, but the common idiom "for i in xrange(sys.maxint)" will
1181 work fine as long as the index i doesn't actually reach 2**31.
1182 (Python uses regular ints for sequence and string indices; fixing
1183 that is much more work.)
1184
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001185- Two changes to from...import:
1186
Guido van Rossumba381232001-02-03 15:06:40 +00001187 1) "from M import X" now works even if (after loading module M)
1188 sys.modules['M'] is not a real module; it's basically a getattr()
1189 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +00001190
1191 2) "from M import *" now looks for M.__all__ to decide which names to
1192 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
1193 filters out names starting with '_' as before. Whether or not
1194 __all__ exists, there's no restriction on the type of M.
1195
Guido van Rossumf61f1662001-01-10 20:13:55 +00001196- File objects have a new method, xreadlines(). This is the fastest
1197 way to iterate over all lines in a file:
1198
1199 for line in file.xreadlines():
1200 ...do something to line...
1201
1202 See the xreadlines module (mentioned below) for how to do this for
1203 other file-like objects.
1204
1205- Even if you don't use file.xreadlines(), you may expect a speedup on
1206 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +00001207 quite a bit in platform-specific ways: on systems (like Linux) that
1208 support flockfile(), getc_unlocked(), and funlockfile(), those are
1209 used by default. On systems (like Windows) without getc_unlocked(),
1210 a complicated (but still thread-safe) method using fgets() is used by
1211 default.
1212
Tim Petersd52269b2001-01-25 06:23:18 +00001213 You can force use of the fgets() method by #define'ing
1214 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +00001215 getc_unlocked()).
1216
Tim Petersd52269b2001-01-25 06:23:18 +00001217 You can force fgets() not to be used by #define'ing
1218 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +00001219 test_bufio.py fails -- and let us know if it does!).
1220
1221- In addition, the fileinput module, while still slower than the other
1222 methods on most platforms, has been sped up too, by using
1223 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001224
1225- Support for run-time warnings has been added, including a new
1226 command line option (-W) to specify the disposition of warnings.
1227 See the description of the warnings module below.
1228
1229- Extensive changes have been made to the coercion code. This mostly
1230 affects extension modules (which can now implement mixed-type
1231 numerical operators without having to use coercion), but
1232 occasionally, in boundary cases the coercion semantics have changed
1233 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +00001234 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +00001235 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +00001236 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +00001237
Guido van Rossumf98eda02001-01-17 15:54:45 +00001238- In connection with the coercion changes, a new built-in singleton
1239 object, NotImplemented is defined. This can be returned for
1240 operations that wish to indicate they are not implemented for a
1241 particular combination of arguments. From C, this is
1242 Py_NotImplemented.
1243
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001244- The interpreter accepts now bytecode files on the command line even
1245 if they do not have a .pyc or .pyo extension. On Linux, after executing
1246
Martin v. Löwise214baa2001-02-04 22:37:56 +00001247import imp,sys,string
1248magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
1249reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
1250open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +00001251
1252 any byte code file can be used as an executable (i.e. as an argument
1253 to execve(2)).
1254
Tim Peters9940b802000-12-01 07:59:35 +00001255- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +00001256 character. In 1.6 and earlier, they never produced a sign,
1257 and raised an error if the value of the long was too large
1258 to fit in a Python int. In 2.0, they produced a sign if and
1259 only if too large to fit in an int. This was inconsistent
1260 across platforms (because the size of an int varies across
1261 platforms), and inconsistent with hex() and oct(). Example:
1262
1263 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +00001264 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +00001265 'ffffffbe' # in 2.0 and before, on 32-bit machines
1266 >>> hex(-0x42L)
1267 '-0x42L' # in all versions of Python
1268
Tim Peters9940b802000-12-01 07:59:35 +00001269 The behavior of %d formats for negative Python longs remains
1270 the same as in 2.0 (although in 1.6 and before, they raised
1271 an error if the long didn't fit in a Python int).
1272
1273 %u formats don't make sense for Python longs, but are allowed
1274 and treated the same as %d in 2.1. In 2.0, a negative long
1275 formatted via %u produced a sign if and only if too large to
1276 fit in an int. In 1.6 and earlier, a negative long formatted
1277 via %u raised an error if it was too big to fit in an int.
1278
Guido van Rossum3661d392000-12-12 22:10:31 +00001279- Dictionary objects have an odd new method, popitem(). This removes
1280 an arbitrary item from the dictionary and returns it (in the form of
1281 a (key, value) pair). This can be useful for algorithms that use a
1282 dictionary as a bag of "to do" items and repeatedly need to pick one
1283 item. Such algorithms normally end up running in quadratic time;
1284 using popitem() they can usually be made to run in linear time.
1285
Tim Peters36cdad12000-12-29 02:06:45 +00001286Standard library
1287
Thomas Woutersfe385252001-01-19 23:16:56 +00001288- In the time module, the time argument to the functions strftime,
1289 localtime, gmtime, asctime and ctime is now optional, defaulting to
1290 the current time (in the local timezone).
1291
Guido van Rossumda91f222001-01-15 16:36:08 +00001292- The ftplib module now defaults to passive mode, which is deemed a
1293 more useful default given that clients are often inside firewalls
1294 these days. Note that this could break if ftplib is used to connect
1295 to a *server* that is inside a firewall, from outside; this is
1296 expected to be a very rare situation. To fix that, you can call
1297 ftp.set_pasv(0).
1298
Martin v. Löwis10a27872001-01-13 09:54:41 +00001299- The module site now treats .pth files not only for path configuration,
1300 but also supports extensions to the initialization code: Lines starting
1301 with import are executed.
1302
Guido van Rossumf61f1662001-01-10 20:13:55 +00001303- There's a new module, warnings, which implements a mechanism for
1304 issuing and filtering warnings. There are some new built-in
1305 exceptions that serve as warning categories, and a new command line
1306 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
1307 turns warnings into errors). warnings.warn(message[, category])
1308 issues a warning message; this can also be called from C as
1309 PyErr_Warn(category, message).
1310
1311- A new module xreadlines was added. This exports a single factory
1312 function, xreadlines(). The intention is that this code is the
1313 absolutely fastest way to iterate over all lines in an open
1314 file(-like) object:
1315
1316 import xreadlines
1317 for line in xreadlines.xreadlines(file):
1318 ...do something to line...
1319
1320 This is equivalent to the previous the speed record holder using
1321 file.readlines(sizehint). Note that if file is a real file object
1322 (as opposed to a file-like object), this is equivalent:
1323
1324 for line in file.xreadlines():
1325 ...do something to line...
1326
Tim Peters36cdad12000-12-29 02:06:45 +00001327- The bisect module has new functions bisect_left, insort_left,
1328 bisect_right and insort_right. The old names bisect and insort
1329 are now aliases for bisect_right and insort_right. XXX_right
1330 and XXX_left methods differ in what happens when the new element
1331 compares equal to one or more elements already in the list: the
1332 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +00001333 right. Code that doesn't care where equal elements end up should
1334 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +00001335
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +00001336- The new curses.panel module wraps the panel library that forms part
1337 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
1338
Guido van Rossumf61f1662001-01-10 20:13:55 +00001339- The SocketServer module now sets the allow_reuse_address flag by
1340 default in the TCPServer class.
1341
1342- A new function, sys._getframe(), returns the stack frame pointer of
1343 the caller. This is intended only as a building block for
1344 higher-level mechanisms such as string interpolation.
1345
Martin v. Löwis2a5130e2001-02-27 04:21:58 +00001346- The pyexpat module supports a number of new handlers, which are
1347 available only in expat 1.2. If invocation of a callback fails, it
1348 will report an additional frame in the traceback. Parser objects
1349 participate now in garbage collection. If expat reports an unknown
1350 encoding, pyexpat will try to use a Python codec; that works only
1351 for single-byte charsets. The parser type objects is exposed as
1352 XMLParserObject.
1353
1354- xml.dom now offers standard definitions for symbolic node type and
1355 exception code constants, and a hierarchy of DOM exceptions. minidom
1356 was adjusted to use them.
1357
1358- The conformance of xml.dom.minidom to the DOM specification was
1359 improved. It detects a number of additional error cases; the
1360 previous/next relationship works even when the tree is modified;
1361 Node supports the normalize() method; NamedNodeMap, DocumentType and
1362 DOMImplementation classes were added; Element supports the
1363 hasAttribute and hasAttributeNS methods; and Text supports the splitText
1364 method.
1365
Guido van Rossumf61f1662001-01-10 20:13:55 +00001366Build issues
1367
Guido van Rossum1e33bdc2001-01-23 03:17:00 +00001368- For Unix (and Unix-compatible) builds, configuration and building of
1369 extension modules is now greatly automated. Rather than having to
1370 edit the Modules/Setup file to indicate which modules should be
1371 built and where their include files and libraries are, a
1372 distutils-based setup.py script now takes care of building most
1373 extension modules. All extension modules built this way are built
1374 as shared libraries. Only a few modules that must be linked
1375 statically are still listed in the Setup file; you won't need to
1376 edit their configuration.
1377
1378- Python should now build out of the box on Cygwin. If it doesn't,
1379 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +00001380
1381- Python now always uses its own (renamed) implementation of getopt()
1382 -- there's too much variation among C library getopt()
1383 implementations.
1384
1385- C++ compilers are better supported; the CXX macro is always set to a
1386 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +00001387
Tim Petersd92dfe02000-12-12 01:18:41 +00001388Windows changes
1389
1390- select module: By default under Windows, a select() call
1391 can specify no more than 64 sockets. Python now boosts
1392 this Microsoft default to 512. If you need even more than
1393 that, see the MS docs (you'll need to #define FD_SETSIZE
1394 and recompile Python from source).
1395
Guido van Rossumf61f1662001-01-10 20:13:55 +00001396- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
1397 subdirectory is no more!
1398
Tim Petersa3a3a032000-11-30 05:22:44 +00001399
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001400What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +00001401=========================
Guido van Rossum61000331997-08-15 04:39:58 +00001402
Guido van Rossum8ed602b2000-09-01 22:34:33 +00001403Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001404changes are in the file HISTORY. If you are making the jump directly
1405from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
1406HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +00001407
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001408Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
1409the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
1410http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +00001411
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001412--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +00001413
1414======================================================================
1415
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001416What's new in 2.0 (since release candidate 1)?
1417==============================================
1418
1419Standard library
1420
1421- The copy_reg module was modified to clarify its intended use: to
1422 register pickle support for extension types, not for classes.
1423 pickle() will raise a TypeError if it is passed a class.
1424
1425- Fixed a bug in gettext's "normalize and expand" code that prevented
1426 it from finding an existing .mo file.
1427
1428- Restored support for HTTP/0.9 servers in httplib.
1429
Tim Peters989b7b92000-10-16 20:24:53 +00001430- The math module was changed to stop raising OverflowError in case of
1431 underflow, and return 0 instead in underflow cases. Whether Python
1432 used to raise OverflowError in case of underflow was platform-
1433 dependent (it did when the platform math library set errno to ERANGE
1434 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001435
1436- Fixed a bug in StringIO that occurred when the file position was not
1437 at the end of the file and write() was called with enough data to
1438 extend past the end of the file.
1439
1440- Fixed a bug that caused Tkinter error messages to get lost on
1441 Windows. The bug was fixed by replacing direct use of
1442 interp->result with Tcl_GetStringResult(interp).
1443
1444- Fixed bug in urllib2 that caused it to fail when it received an HTTP
1445 redirect response.
1446
1447- Several changes were made to distutils: Some debugging code was
1448 removed from util. Fixed the installer used when an external zip
1449 program (like WinZip) is not found; the source code for this
1450 installer is in Misc/distutils. check_lib() was modified to behave
1451 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
1452 test for whether installed modules are on sys.path was changed to
1453 use both normcase() and normpath().
1454
Jeremy Hyltond867a2c2000-10-16 20:41:38 +00001455- Several minor bugs were fixed in the xml package (the minidom,
1456 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001457
1458- The regression test driver (regrtest.py) behavior when invoked with
1459 -l changed: It now reports a count of objects that are recognized as
1460 garbage but not freed by the garbage collector.
1461
Tim Peters989b7b92000-10-16 20:24:53 +00001462- The regression test for the math module was changed to test
1463 exceptional behavior when the test is run in verbose mode. Python
1464 cannot yet guarantee consistent exception behavior across platforms,
1465 so the exception part of test_math is run only in verbose mode, and
1466 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001467
1468Internals
1469
1470- PyOS_CheckStack() has been disabled on Win64, where it caused
1471 test_sre to fail.
1472
1473Build issues
1474
1475- Changed compiler flags, so that gcc is always invoked with -Wall and
1476 -Wstrict-prototypes. Users compiling Python with GCC should see
1477 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +00001478 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +00001479 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001480
Tim Petersa3a3a032000-11-30 05:22:44 +00001481- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001482
1483Tools and other miscellany
1484
1485- The compiler in Tools/compiler was updated to support the new
1486 language features introduced in 2.0: extended print statement, list
1487 comprehensions, and augmented assignments. The new compiler should
1488 also be backwards compatible with Python 1.5.2; the compiler will
1489 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +00001490 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001491
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001492What's new in 2.0 release candidate 1 (since beta 2)?
1493=====================================================
1494
Jeremy Hylton6040aaa2000-10-09 21:27:22 +00001495What is release candidate 1?
1496
1497We believe that release candidate 1 will fix all known bugs that we
1498intend to fix for the 2.0 final release. This release should be a bit
1499more stable than the previous betas. We would like to see even more
1500widespread testing before the final release, so we are producing this
1501release candidate. The final release will be exactly the same unless
1502any show-stopping (or brown bag) bugs are found by testers of the
1503release candidate.
1504
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001505All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001506to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001507
1508Core language, builtins, and interpreter
1509
1510- A bug that caused crashes when __coerce__ was used with augmented
1511 assignment, e.g. +=, was fixed.
1512
1513- Raise ZeroDivisionError when raising zero to a negative number,
1514 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
1515 power operator and the result of math.pow(0.0, -2.0) will vary by
1516 platform. On Linux, it raises a ValueError.
1517
1518- A bug in Unicode string interpolation was fixed that occasionally
1519 caused errors with formats including "%%". For example, the
1520 following expression "%% %s" % u"abc" no longer raises a TypeError.
1521
1522- Compilation of deeply nested expressions raises MemoryError instead
1523 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
1524
1525- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
1526 rendering them useless. They are now written in binary mode again.
1527
1528Standard library
1529
1530- Keyword arguments are now accepted for most pattern and match object
1531 methods in SRE, the standard regular expression engine.
1532
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001533- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +00001534 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001535
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001536- Several bugs in the Unicode handling and error handling in _tkinter
1537 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001538
1539- Fix memory management errors in Merge() and Tkapp_Call() routines.
1540
1541- Several changes were made to cStringIO to make it compatible with
1542 the file-like object interface and with StringIO. If operations are
1543 performed on a closed object, an exception is raised. The truncate
1544 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +00001545 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001546
1547- There were many changes made to the linuxaudiodev module and its
1548 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +00001549 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001550
1551 Note that this module is named poorly, because it should work
1552 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +00001553 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001554
1555 The module now raises exceptions when errors occur instead of
1556 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
1557 audio) and defines a getptr() method that calls the
1558 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
1559
1560- The library_version attribute, introduced in an earlier beta, was
1561 removed because it can not be supported with early versions of the C
1562 readline library, which provides no way to determine the version at
1563 compile-time.
1564
1565- The binascii module is now enabled on Win64.
1566
Tim Peters46446d62000-10-09 21:19:31 +00001567- tokenize.py no longer suffers "recursion depth" errors when parsing
1568 programs with very long string literals.
1569
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001570Internals
1571
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001572- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001573 which is called when the interpreter starts up to determine where
1574 the standard library is installed. These vulnerabilities affect all
1575 previous versions of Python and can be exploited by setting very
1576 long values for PYTHONHOME or argv[0]. The risk is greatest for a
1577 setuid Python script, although use of the wrapper in
1578 Misc/setuid-prog.c will eliminate the vulnerability.
1579
1580- Fixed garbage collection bugs in instance creation that were
1581 triggered when errors occurred during initialization. The solution,
1582 applied in cPickle and in PyInstance_New(), is to call
1583 PyObject_GC_Init() after the initialization of the object's
1584 container attributes is complete.
1585
1586- pyexpat adds definitions of PyModule_AddStringConstant and
1587 PyModule_AddObject if the Python version is less than 2.0, which
1588 provides compatibility with PyXML on Python 1.5.2.
1589
1590- If the platform has a bogus definition for LONG_BIT (the number of
1591 bits in a long), an error will be reported at compile time.
1592
1593- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
1594 collection crashes and possibly other, unreported crashes.
1595
1596- Fixed a memory leak in _PyUnicode_Fini().
1597
1598Build issues
1599
1600- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001601 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +00001602 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001603
1604- The mmap.PAGESIZE constant is now initialized using sysconf when
1605 possible, which eliminates a dependency on -lucb for Reliant UNIX.
1606
1607- The md5 file should now compile on all platforms.
1608
1609- The select module now compiles on platforms that do not define
1610 POLLRDNORM and related constants.
1611
1612- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +00001613 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001614
Jeremy Hylton10921202000-10-09 18:34:12 +00001615- BeOS: A number of changes were made to the build and installation
1616 process. ar-fake now operates on a directory of object files.
1617 dl_export.h is gone, and its macros now appear on the mwcc command
1618 line during build on PPC BeOS.
1619
Jeremy Hyltond6e20232000-10-16 20:08:38 +00001620- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +00001621 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +00001622
1623- Cygwin: Support for shared libraries, Tkinter, and sockets.
1624
1625- SunOS 4.1.4_JL: Fix test for directory existence in configure.
1626
1627Tools and other miscellany
1628
1629- Removed debugging prints from main used with freeze.
1630
Tim Peters46446d62000-10-09 21:19:31 +00001631- IDLE auto-indent no longer crashes when it encounters Unicode
1632 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001633
1634What's new in 2.0 beta 2 (since beta 1)?
1635========================================
1636
1637Core language, builtins, and interpreter
1638
Tim Peters482c0212000-09-26 06:33:09 +00001639- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001640 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001641
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001642- Add -h and -V command line options to print the usage message and
1643 Python version number and exit immediately.
1644
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001645- eval() and exec accept Unicode objects as code parameters.
1646
1647- getattr() and setattr() now also accept Unicode objects for the
1648 attribute name, which are converted to strings using the default
1649 encoding before lookup.
1650
1651- Multiplication on string and Unicode now does proper bounds
1652 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
1653 string is too long."
1654
1655- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +00001656 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001657
Jeremy Hylton1b618592000-09-26 05:32:36 +00001658
1659Standard library and extensions
1660
Guido van Rossum5b08f132001-04-16 02:05:23 +00001661- socket module: the OpenSSL code now adds support for RAND_status()
1662 and EGD (Entropy Gathering Device).
1663
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001664- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +00001665 argument checking; it still takes no arguments.
1666
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001667- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001668
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001669- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001670
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001671- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001672
1673- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001674 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001675
1676- copy: Copy Unicode objects atomically.
1677
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001678- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001679
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001680- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001681
Fred Drake67233bc2000-09-26 16:40:27 +00001682- dbm: Add get() and setdefault() methods to dbm object. Add constant
1683 `library' to module that names the library used. Added doc strings
1684 and method names to error messages. Uses configure to determine
1685 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
1686 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001687
1688- distutils: Update to version 0.9.3.
1689
1690- dl: Add several dl.RTLD_ constants.
1691
1692- fpectl: Now supported on FreeBSD.
1693
1694- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
1695 found by the collector will be saved in gc.garbage. This is useful
1696 for debugging a program that creates reference cycles.
1697
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001698- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +00001699 of HTTP class. Do not close socket on zero-length response. Do not
1700 crash when server sends invalid content-length header.
1701
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001702- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001703
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001704- marshal: When reading a short, sign-extend on platforms where shorts
1705 are bigger than 16 bits. When reading a long, repair the unportable
1706 sign extension that was being done for 64-bit machines. (It assumed
1707 that signed right shift sign-extends.)
1708
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001709- operator: Add contains(), invert(), __invert__() as aliases for
1710 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001711
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001712- os: Add support for popen2() and popen3() on all platforms where
1713 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001714
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001715- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +00001716 clicking on a file in Explorer (or passing the file name to the
1717 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001718
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001719- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +00001720 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +00001721
1722- pickle: Now raises ValueError when an invalid pickle that contains
1723 a non-string repr where a string repr was expected. This behavior
1724 matches cPickle.
1725
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001726- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001727
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001728- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001729
1730- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001731 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001732 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001733
1734- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001735 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001736
1737- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00001738 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00001739 few cycles during startup since the first call to
1740 setdefaultencoding() will initialize the codec registry and the
1741 encodings package.
1742
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001743- socket: Support for size hint in readlines() method of object returned
1744 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001745
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001746- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001747 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001748 is followed by whitespace.
1749
Tim Petersa3a3a032000-11-30 05:22:44 +00001750- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001751
1752- struct: Check ranges for bytes and shorts.
1753
1754- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001755 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001756
1757- Tkinter: Image objects are now guaranteed to have unique ids. Set
1758 event.delta to zero if Tk version doesn't support mousewheel.
1759 Removed some debugging prints.
1760
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001761- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001762
Fred Drake67233bc2000-09-26 16:40:27 +00001763- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001764 which works around a bug in Norton AntiVirus 2000 that leads directly
1765 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001766
1767- xml: New version detection code allows PyXML to override standard
1768 XML package if PyXML version is greater than 0.6.1.
1769
Fred Drake64bb3802000-09-26 16:21:35 +00001770- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
1771 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
1772 tree only for nodes which are sufficiently interesting to a specific
1773 application. Does not provide the HTML-specific extensions. Still
1774 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001775
Fred Drake64bb3802000-09-26 16:21:35 +00001776- xml.sax: SAX 2 support for Python, including all the handler
1777 interfaces needed to process XML 1.0 compliant XML. Some
1778 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001779
Fred Drake64bb3802000-09-26 16:21:35 +00001780- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
1781 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001782
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001783
Jeremy Hylton1b618592000-09-26 05:32:36 +00001784C API
1785
1786- Add three new convenience functions for module initialization --
1787 PyModule_AddObject(), PyModule_AddIntConstant(), and
1788 PyModule_AddStringConstant().
1789
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001790- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00001791 removed and add #error to Python.h if NULL isn't defined after
1792 #include of stdio.h.
1793
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001794- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00001795 backwards compatibility (at the source level) with old extensions.
1796
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001797- A wrapper API was added for signal() and sigaction(). Instead of
1798 either function, always use PyOS_getsig() to get a signal handler
1799 and PyOS_setsig() to set one. A new convenience typedef
1800 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001801
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001802- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00001803 internal data buffer and size of a string object -- or the default
1804 encoded version of a Unicode object.
1805
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001806- PyString_Size() and PyString_AsString() accept Unicode objects.
1807
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001808- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00001809 exists). INT_MAX and LONG_MAX will always be defined, even if
1810 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001811
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001812- PyFloat_FromString takes a second argument, pend, that was
1813 effectively useless. It is now officially useless but preserved for
1814 backwards compatibility. If the pend argument is not NULL, *pend is
1815 set to NULL.
1816
1817- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
1818 for the attribute name. See note on getattr() above.
1819
1820- A few bug fixes to argument processing for Unicode.
1821 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
1822 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
1823 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00001824 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001825
1826- Py_BuildValue accepts B format (for bgen-generated code).
1827
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001828
Jeremy Hylton1b618592000-09-26 05:32:36 +00001829Internals
1830
1831- On Unix, fix code for finding Python installation directory so that
1832 it works when argv[0] is a relative path.
1833
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00001834- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001835 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00001836 rather than by generating a copy of the object.
1837
Tim Peters482c0212000-09-26 06:33:09 +00001838- Several of the internal Unicode tables are much smaller now, and
1839 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001840
Jeremy Hylton97693b02000-09-26 17:42:51 +00001841- In the garbage collector: Fixed bug in collection of tuples. Fixed
1842 bug that caused some instances to be removed from the container set
1843 while they were still live. Fixed parsing in gc.set_debug() for
1844 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001845
1846- Fixed refcount problem in instance deallocation that only occurred
1847 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
1848
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001849- On Windows, getpythonregpath is now protected against null data in
1850 registry key.
1851
1852- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00001853 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001854
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001855
Jeremy Hylton1b618592000-09-26 05:32:36 +00001856Build and platform-specific issues
1857
1858- Better support of GNU Pth via --with-pth configure option.
1859
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001860- Python/C API now properly exposed to dynamically-loaded extension
1861 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001862
1863- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
1864 Don't define MS_SYNC to be zero when it is undefined. Added missing
1865 prototypes in posixmodule.c.
1866
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001867- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001868 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001869
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001870- Fix largefile support on older NetBSD systems and OpenBSD by adding
1871 define for TELL64.
1872
1873
1874Tools and other miscellany
1875
1876- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
1877
1878- freeze: The modulefinder now works with 2.0 opcodes.
1879
Tim Petersa3a3a032000-11-30 05:22:44 +00001880- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001881 Move hackery of sys.argv until after the Tk instance has been
1882 created, which allows the application-specific Tkinter
1883 initialization to be executed if present; also pass an explicit
1884 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00001885
Jeremy Hylton1b618592000-09-26 05:32:36 +00001886
1887What's new in 2.0 beta 1?
1888=========================
1889
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001890Source Incompatibilities
1891------------------------
1892
1893None. Note that 1.6 introduced several incompatibilities with 1.5.2,
1894such as single-argument append(), connect() and bind(), and changes to
1895str(long) and repr(float).
1896
1897
1898Binary Incompatibilities
1899------------------------
1900
1901- Third party extensions built for Python 1.5.x or 1.6 cannot be used
1902with Python 2.0; these extensions will have to be rebuilt for Python
19032.0.
1904
1905- On Windows, attempting to import a third party extension built for
1906Python 1.5.x or 1.6 results in an immediate crash; there's not much we
1907can do about this. Check your PYTHONPATH environment variable!
1908
1909- Python bytecode files (*.pyc and *.pyo) are not compatible between
1910releases.
1911
1912
1913Overview of Changes Since 1.6
1914-----------------------------
1915
1916There are many new modules (including brand new XML support through
1917the xml package, and i18n support through the gettext module); a list
1918of all new modules is included below. Lots of bugs have been fixed.
1919
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001920The process for making major new changes to the language has changed
1921since Python 1.6. Enhancements must now be documented by a Python
1922Enhancement Proposal (PEP) before they can be accepted.
1923
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001924There are several important syntax enhancements, described in more
1925detail below:
1926
1927 - Augmented assignment, e.g. x += 1
1928
1929 - List comprehensions, e.g. [x**2 for x in range(10)]
1930
1931 - Extended import statement, e.g. import Module as Name
1932
1933 - Extended print statement, e.g. print >> file, "Hello"
1934
1935Other important changes:
1936
1937 - Optional collection of cyclical garbage
1938
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001939Python Enhancement Proposal (PEP)
1940---------------------------------
1941
1942PEP stands for Python Enhancement Proposal. A PEP is a design
1943document providing information to the Python community, or describing
1944a new feature for Python. The PEP should provide a concise technical
1945specification of the feature and a rationale for the feature.
1946
1947We intend PEPs to be the primary mechanisms for proposing new
1948features, for collecting community input on an issue, and for
1949documenting the design decisions that have gone into Python. The PEP
1950author is responsible for building consensus within the community and
1951documenting dissenting opinions.
1952
1953The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001954
1955Augmented Assignment
1956--------------------
1957
1958This must have been the most-requested feature of the past years!
1959Eleven new assignment operators were added:
1960
Guido van Rossume905e952000-09-05 12:42:46 +00001961 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001962
1963For example,
1964
1965 A += B
1966
1967is similar to
1968
1969 A = A + B
1970
1971except that A is evaluated only once (relevant when A is something
1972like dict[index].attr).
1973
1974However, if A is a mutable object, A may be modified in place. Thus,
1975if A is a number or a string, A += B has the same effect as A = A+B
1976(except A is only evaluated once); but if a is a list, A += B has the
1977same effect as A.extend(B)!
1978
1979Classes and built-in object types can override the new operators in
1980order to implement the in-place behavior; the not-in-place behavior is
1981used automatically as a fallback when an object doesn't implement the
1982in-place behavior. For classes, the method name is derived from the
1983method name for the corresponding not-in-place operator by inserting
1984an 'i' in front of the name, e.g. __iadd__ implements in-place
1985__add__.
1986
1987Augmented assignment was implemented by Thomas Wouters.
1988
1989
1990List Comprehensions
1991-------------------
1992
1993This is a flexible new notation for lists whose elements are computed
1994from another list (or lists). The simplest form is:
1995
1996 [<expression> for <variable> in <sequence>]
1997
Guido van Rossum56db0952000-09-06 23:34:25 +00001998For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001999This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002000
2001You can also add a condition:
2002
2003 [<expression> for <variable> in <sequence> if <condition>]
2004
2005For example, [w for w in words if w == w.lower()] would yield the list
2006of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002007than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002008
2009You can also have nested for loops and more than one 'if' clause. For
2010example, here's a function that flattens a sequence of sequences::
2011
2012 def flatten(seq):
2013 return [x for subseq in seq for x in subseq]
2014
2015 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
2016
2017This prints
2018
2019 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2020
2021List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002022Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002023
2024
2025Extended Import Statement
2026-------------------------
2027
2028Many people have asked for a way to import a module under a different
2029name. This can be accomplished like this:
2030
2031 import foo
2032 bar = foo
2033 del foo
2034
2035but this common idiom gets old quickly. A simple extension of the
2036import statement now allows this to be written as follows:
2037
2038 import foo as bar
2039
2040There's also a variant for 'from ... import':
2041
2042 from foo import bar as spam
2043
2044This also works with packages; e.g. you can write this:
2045
2046 import test.regrtest as regrtest
2047
2048Note that 'as' is not a new keyword -- it is recognized only in this
2049context (this is only possible because the syntax for the import
2050statement doesn't involve expressions).
2051
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002052Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002053
2054
2055Extended Print Statement
2056------------------------
2057
2058Easily the most controversial new feature, this extension to the print
2059statement adds an option to make the output go to a different file
2060than the default sys.stdout.
2061
2062For example, to write an error message to sys.stderr, you can now
2063write:
2064
2065 print >> sys.stderr, "Error: bad dog!"
2066
2067As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00002068evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002069
2070 print >> None, "Hello world"
2071
2072is equivalent to
2073
2074 print "Hello world"
2075
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002076Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002077
2078
2079Optional Collection of Cyclical Garbage
2080---------------------------------------
2081
2082Python is now equipped with a garbage collector that can hunt down
2083cyclical references between Python objects. It's no replacement for
2084reference counting; in fact, it depends on the reference counts being
2085correct, and decides that a set of objects belong to a cycle if all
2086their reference counts can be accounted for from their references to
2087each other. This devious scheme was first proposed by Eric Tiedemann,
2088and brought to implementation by Neil Schemenauer.
2089
2090There's a module "gc" that lets you control some parameters of the
2091garbage collection. There's also an option to the configure script
2092that lets you enable or disable the garbage collection. In 2.0b1,
2093it's on by default, so that we (hopefully) can collect decent user
2094experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00002095performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002096off by default in the final 2.0 release.
2097
2098
2099Smaller Changes
2100---------------
2101
2102A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
2103map(None, seq1, seq2, ...) when the sequences have the same length;
2104i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
2105the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002106zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002107
2108sys.version_info is a tuple (major, minor, micro, level, serial).
2109
2110Dictionaries have an odd new method, setdefault(key, default).
2111dict.setdefault(key, default) returns dict[key] if it exists; if not,
2112it sets dict[key] to default and returns that value. Thus:
2113
2114 dict.setdefault(key, []).append(item)
2115
2116does the same work as this common idiom:
2117
2118 if not dict.has_key(key):
2119 dict[key] = []
2120 dict[key].append(item)
2121
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002122There are two new variants of SyntaxError that are raised for
2123indentation-related errors: IndentationError and TabError.
2124
2125Changed \x to consume exactly two hex digits; see PEP 223. Added \U
2126escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002127
2128The limits on the size of expressions and file in Python source code
2129have been raised from 2**16 to 2**32. Previous versions of Python
2130were limited because the maximum argument size the Python VM accepted
2131was 2**16. This limited the size of object constructor expressions,
2132e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
2133limit was raised thanks to a patch by Charles Waldman that effectively
2134fixes the problem. It is now much more likely that you will be
2135limited by available memory than by an arbitrary limit in Python.
2136
2137The interpreter's maximum recursion depth can be modified by Python
2138programs using sys.getrecursionlimit and sys.setrecursionlimit. This
2139limit is the maximum number of recursive calls that can be made by
2140Python code. The limit exists to prevent infinite recursion from
2141overflowing the C stack and causing a core dump. The default value is
21421000. The maximum safe value for a particular platform can be found
2143by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002144
2145New Modules and Packages
2146------------------------
2147
2148atexit - for registering functions to be called when Python exits.
2149
2150imputil - Greg Stein's alternative API for writing custom import
2151hooks.
2152
2153pyexpat - an interface to the Expat XML parser, contributed by Paul
2154Prescod.
2155
2156xml - a new package with XML support code organized (so far) in three
2157subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
2158would fill a volume. There's a special feature whereby a
2159user-installed package named _xmlplus overrides the standard
2160xmlpackage; this is intended to give the XML SIG a hook to distribute
2161backwards-compatible updates to the standard xml package.
2162
2163webbrowser - a platform-independent API to launch a web browser.
2164
2165
Guido van Rossume905e952000-09-05 12:42:46 +00002166Changed Modules
2167---------------
2168
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002169array -- new methods for array objects: count, extend, index, pop, and
2170remove
2171
2172binascii -- new functions b2a_hex and a2b_hex that convert between
2173binary data and its hex representation
2174
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002175calendar -- Many new functions that support features including control
2176over which day of the week is the first day, returning strings instead
2177of printing them. Also new symbolic constants for days of week,
2178e.g. MONDAY, ..., SUNDAY.
2179
2180cgi -- FieldStorage objects have a getvalue method that works like a
2181dictionary's get method and returns the value attribute of the object.
2182
2183ConfigParser -- The parser object has new methods has_option,
2184remove_section, remove_option, set, and write. They allow the module
2185to be used for writing config files as well as reading them.
2186
2187ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00002188optionally support the RFC 959 REST command.
2189
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002190gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00002191
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002192httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
2193the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00002194
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002195locale -- implement getdefaultlocale for Win32 and Macintosh
2196
2197marshal -- no longer dumps core when marshaling deeply nested or
2198recursive data structures
2199
2200os -- new functions isatty, seteuid, setegid, setreuid, setregid
2201
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002202os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
2203support under Unix.
2204
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002205os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002206
2207os.path -- fix semantics of os.path.commonprefix
2208
2209smtplib -- support for sending very long messages
2210
2211socket -- new function getfqdn()
2212
2213readline -- new functions to read, write and truncate history files.
2214The readline section of the library reference manual contains an
2215example.
2216
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002217select -- add interface to poll system call
2218
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002219shutil -- new copyfileobj function
2220
2221SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
2222HTTP server.
2223
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002224Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002225
2226urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00002227e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002228
2229whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00002230
2231
2232Obsolete Modules
2233----------------
2234
2235None. However note that 1.6 made a whole slew of modules obsolete:
2236stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
2237poly, zmod, strop, util, whatsound.
2238
2239
2240Changed, New, Obsolete Tools
2241----------------------------
2242
Tim Peters8b092332000-09-05 20:15:25 +00002243None.
Guido van Rossume905e952000-09-05 12:42:46 +00002244
2245
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002246C-level Changes
2247---------------
2248
2249Several cleanup jobs were carried out throughout the source code.
2250
2251All C code was converted to ANSI C; we got rid of all uses of the
2252Py_PROTO() macro, which makes the header files a lot more readable.
2253
2254Most of the portability hacks were moved to a new header file,
2255pyport.h; several other new header files were added and some old
2256header files were removed, in an attempt to create a more rational set
2257of header files. (Few of these ever need to be included explicitly;
2258they are all included by Python.h.)
2259
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002260Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002261and Win64, especially for the new Intel Itanium processor. Mick also
2262added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00002263
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002264The C APIs to return an object's size have been update to consistently
2265use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
2266previous versions, the abstract interfaces used PyXXX_Length and the
2267concrete interfaces used PyXXX_Size. The old names,
2268e.g. PyObject_Length, are still available for backwards compatibility
2269at the API level, but are deprecated.
2270
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002271The PyOS_CheckStack function has been implemented on Windows by
2272Fredrik Lundh. It prevents Python from failing with a stack overflow
2273on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002274
2275The GC changes resulted in creation of two new slots on object,
2276tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00002277the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002278
2279The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00002280C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002281
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002282PyErr_Format has been updated to automatically calculate the size of
2283the buffer needed to hold the formatted result string. This change
2284prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00002285
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002286New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00002287
Jeremy Hylton24c3d602000-09-05 19:36:26 +00002288PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
2289that are the same as their non-Ex counterparts except they take an
2290extra flag argument that tells them to close the file when done.
2291
2292XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002293
Tim Peters8b092332000-09-05 20:15:25 +00002294
2295Windows Changes
2296---------------
2297
2298New popen2/popen3/peopen4 in os module (see Changed Modules above).
2299
2300os.popen is much more usable on Windows 95 and 98. See Microsoft
2301Knowledge Base article Q150956. The Win9x workaround described there
2302is implemented by the new w9xpopen.exe helper in the root of your
2303Python installation. Note that Python uses this internally; it is not
2304a standalone program.
2305
2306Administrator privileges are no longer required to install Python
2307on Windows NT or Windows 2000. If you have administrator privileges,
2308Python's registry info will be written under HKEY_LOCAL_MACHINE.
2309Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00002310under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00002311uses of Python, but will prevent some advanced uses from working
2312(for example, running a Python script as an NT service, or possibly
2313from CGI).
2314
2315[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
2316installer; instead, it installs the needed Tcl/Tk files directly in the
2317Python directory. If you already have a Tcl/Tk installation, this
2318wastes some disk space (about 4 Megs) but avoids problems with
2319conflicting Tcl/Tk installations, and makes it much easier for Python
2320to ensure that Tcl/Tk can find all its files.
2321
2322[This was new in 1.6] The Windows installer now installs by default in
2323\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
2324
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00002325
2326Updates to the changes between 1.5.2 and 1.6
2327--------------------------------------------
2328
2329The 1.6 NEWS file can't be changed after the release is done, so here
2330is some late-breaking news:
2331
2332New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
2333and changes to getlocale() and setlocale().
2334
2335The new module is now enabled per default.
2336
2337It is not true that the encodings codecs cannot be used for normal
2338strings: the string.encode() (which is also present on 8-bit strings
2339!) allows using them for 8-bit strings too, e.g. to convert files from
2340cp1252 (Windows) to latin-1 or vice-versa.
2341
2342Japanese codecs are available from Tamito KAJIYAMA:
2343http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
2344
2345
Guido van Rossumab9d6f01998-08-10 22:01:13 +00002346======================================================================