blob: 92def290a592a4122992462a4ed2b9d7b2a1eb40 [file] [log] [blame]
Barry Warsaw11e89c72001-04-11 20:37:57 +00001What's New in Python 2.1 final?
2===============================
3
4- An updated python-mode.el version 4.0 which integrates Ken
5 Manheimer's pdbtrack.el. This makes debugging Python code via pdb
6 much nicer in XEmacs and Emacs. When stepping through your program
7 with pdb, in either the shell window or the *Python* window, the
8 source file and line will be tracked by an arrow.
9
10
Martin v. Löwis0411f6f2001-03-21 08:01:39 +000011What's New in Python 2.1 beta 2?
12================================
13
Guido van Rossum053ae352001-03-22 14:17:21 +000014(Unlisted are many fixed bugs, more documentation, etc.)
15
Martin v. Löwis0411f6f2001-03-21 08:01:39 +000016Core language, builtins, and interpreter
17
Guido van Rossum053ae352001-03-22 14:17:21 +000018- The nested scopes work (enabled by "from __future__ import
19 nested_scopes") is completed; in particular, the future now extends
20 into code executed through exec, eval() and execfile(), and into the
21 interactive interpreter.
22
23- When calling a base class method (e.g. BaseClass.__init__(self)),
24 this is now allowed even if self is not strictly spoken a class
25 instance (e.g. when using metaclasses or the Don Beaudry hook).
26
27- Slice objects are now comparable but not hashable; this prevents
28 dict[:] from being accepted but meaningless.
29
30- Complex division is now calculated using less braindead algorithms.
31 This doesn't change semantics except it's more likely to give useful
32 results in extreme cases. Complex repr() now uses full precision
33 like float repr().
34
35- sgmllib.py now calls handle_decl() for simple <!...> declarations.
36
Jeremy Hyltonf626db72001-03-23 14:18:27 +000037- It is illegal to assign to the name __debug__, which is set when the
38 interpreter starts. It is effectively a compile-time constant.
39
40- A warning will be issued if a global statement for a variable
41 follows a use or assignment of that variable.
42
Martin v. Löwis0411f6f2001-03-21 08:01:39 +000043Standard library
44
Guido van Rossum053ae352001-03-22 14:17:21 +000045- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
46 inspired by JUnit), is now part of the standard library. You now
47 have a choice of two testing frameworks: unittest requires you to
48 write testcases as separate code, doctest gathers them from
49 docstrings. Both approaches have their advantages and
50 disadvantages.
51
52- A new module Tix was added, which wraps the Tix extension library
53 for Tk. With that module, it is not necessary to statically link
54 Tix with _tkinter, since Tix will be loaded with Tcl's "package
55 require" command. See Demo/tix/.
56
57- tzparse.py is now obsolete.
58
59- In gzip.py, the seek() and tell() methods are removed -- they were
60 non-functional anyway, and it's better if callers can test for their
61 existence with hasattr().
62
63Python/C API
64
65- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
66 that's already in the dictionary during a PyDict_Next() iteration.
67 This used to fail occasionally when a dictionary resize operation
68 could be triggered that would rehash all the keys. All other
69 modifications to the dictionary are still off-limits during a
70 PyDict_Next() iteration!
71
72- New extended APIs related to passing compiler variables around.
73
74- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
75 implement isinstance() and issubclass().
76
77- Py_BuildValue() now has a "D" conversion to create a Python complex
78 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +000079
Fred Drake4e262a92001-03-22 18:26:47 +000080- Extensions types which support weak references must now set the
81 field allocated for the weak reference machinery to NULL themselves;
82 this is done to avoid the cost of checking each object for having a
83 weakly referencable type in PyObject_INIT(), since most types are
84 not weakly referencable.
85
Jeremy Hyltonf626db72001-03-23 14:18:27 +000086- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
87 free variables and cell variables to and from the frame's f_locals.
88
89- Variants of several functions defined in pythonrun.h have been added
90 to support the nested_scopes future statement. The variants all end
91 in Flags and take an extra argument, a PyCompilerFlags *; examples:
92 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
93 variants may be removed in Python 2.2, when nested scopes are
94 mandatory.
95
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +000096Distutils
97
98- the sdist command now writes a PKG-INFO file, as described in PEP 241,
99 into the release tree.
100
101- several enhancements to the bdist_wininst command from Thomas Heller
102 (an uninstaller, more customization of the installer's display)
103
104- from Jack Jansen: added Mac-specific code to generate a dialog for
105 users to specify the command-line (because providing a command-line with
106 MacPython is awkward). Jack also made various fixes for the Mac
107 and the Metrowerks compiler.
108
109- added 'platforms' and 'keywords' to the set of metadata that can be
Andrew M. Kuchling68ad64a2001-03-31 02:42:42 +0000110 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000111
112- applied patches from Jason Tishler to make the compiler class work with
113 Cygwin.
114
115
Tim Peters2fe289a2001-03-01 22:19:38 +0000116What's New in Python 2.1 beta 1?
117================================
Tim Petersd66595f2001-02-04 03:09:53 +0000118
119Core language, builtins, and interpreter
120
Guido van Rossum9d0fbde2001-03-02 14:00:32 +0000121- Following an outcry from the community about the amount of code
122 broken by the nested scopes feature introduced in 2.1a2, we decided
123 to make this feature optional, and to wait until Python 2.2 (or at
124 least 6 months) to make it standard. The option can be enabled on a
125 per-module basis by adding "from __future__ import nested_scopes" at
126 the beginning of a module (before any other statements, but after
127 comments and an optional docstring). See PEP 236 (Back to the
128 __future__) for a description of the __future__ statement. PEP 227
129 (Statically Nested Scopes) has been updated to reflect this change,
130 and to clarify the semantics in a number of endcases.
131
132- The nested scopes code, when enabled, has been hardened, and most
133 bugs and memory leaks in it have been fixed.
134
135- Compile-time warnings are now generated for a number of conditions
136 that will break or change in meaning when nested scopes are enabled:
137
138 - Using "from...import *" or "exec" without in-clause in a function
139 scope that also defines a lambda or nested function with one or
140 more free (non-local) variables. The presence of the import* or
141 bare exec makes it impossible for the compiler to determine the
142 exact set of local variables in the outer scope, which makes it
143 impossible to determine the bindings for free variables in the
144 inner scope. To avoid the warning about import *, change it into
145 an import of explicitly name object, or move the import* statement
146 to the global scope; to avoid the warning about bare exec, use
147 exec...in... (a good idea anyway -- there's a possibility that
148 bare exec will be deprecated in the future).
149
150 - Use of a global variable in a nested scope with the same name as a
151 local variable in a surrounding scope. This will change in
152 meaning with nested scopes: the name in the inner scope will
153 reference the variable in the outer scope rather than the global
154 of the same name. To avoid the warning, either rename the outer
155 variable, or use a global statement in the inner function.
156
Neil Schemenauera35c6882001-02-27 04:45:05 +0000157- An optional object allocator has been included. This allocator is
158 optimized for Python objects and should be faster and use less memory
159 than the standard system allocator. It is not enabled by default
160 because of possible thread safety problems. The allocator is only
161 protected by the Python interpreter lock and it is possible that some
162 extension modules require a thread safe allocator. The object
163 allocator can be enabled by providing the "--with-pymalloc" option to
164 configure.
165
Tim Petersd66595f2001-02-04 03:09:53 +0000166Standard library
167
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000168- pyexpat now detects the expat version if expat.h defines it. A
169 number of additional handlers are provided, which are only available
170 since expat 1.95. In addition, the methods SetParamEntityParsing and
171 GetInputContext of Parser objects are available with 1.95.x
172 only. Parser objects now provide the ordered_attributes and
173 specified_attributes attributes. A new module expat.model was added,
174 which offers a number of additional constants if 1.95.x is used.
175
176- xml.dom offers the new functions registerDOMImplementation and
177 getDOMImplementation.
178
179- xml.dom.minidom offers a toprettyxml method. A number of DOM
180 conformance issues have been resolved. In particular, Element now
181 has an hasAttributes method, and the handling of namespaces was
182 improved.
183
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000184- Ka-Ping Yee contributed two new modules: inspect.py, a module for
185 getting information about live Python code, and pydoc.py, a module
186 for interactively converting docstrings to HTML or text.
187 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +0000188 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +0000189 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
190 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000191
Tim Peters1eff7962001-03-01 02:31:33 +0000192- New library module difflib.py, primarily packaging the SequenceMatcher
193 class at the heart of the popular ndiff.py file-comparison tool.
194
195- doctest.py (a framework for verifying Python code examples in docstrings)
196 is now part of the std library.
197
Tim Petersd66595f2001-02-04 03:09:53 +0000198Windows changes
199
Guido van Rossume3955a82001-03-02 14:05:59 +0000200- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
201 small GUI that lets you browse the module docstrings using your
202 default web browser.
203
Tim Peters1eff7962001-03-01 02:31:33 +0000204- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
205 Platforms) is implemented. See
206
207 http://python.sourceforge.net/peps/pep-0235.html
208
209 for full details, especially the "Current Lower-Left Semantics" section.
210 The new Windows import rules are simpler than before:
211
212 A. If the PYTHONCASEOK environment variable exists, same as
213 before: silently accept the first case-insensitive match of any
214 kind; raise ImportError if none found.
215
216 B. Else search sys.path for the first case-sensitive match; raise
217 ImportError if none found.
218
219 The same rules have been implented on other platforms with case-
220 insensitive but case-preserving filesystems too (including Cygwin, and
221 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +0000222
Tim Peters25a9ce32001-02-19 07:06:36 +0000223- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
224 what it's supposed to do (and does do under NT and 2000) via direct
225 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +0000226 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +0000227 all Win9x systems before.
228
Tim Peters1eff7962001-03-01 02:31:33 +0000229- Build: Subproject _test (effectively) renamed to _testcapi.
230
Tim Peters2fe289a2001-03-01 22:19:38 +0000231New platforms
232
233- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
234 Thanks to Steven Majewski!
235
236- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
237 Tishler!
238
Guido van Rossum9089b272001-03-02 06:49:50 +0000239- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
240 Schwertberger! See RISCOS/README for more information -- it seems
241 that because of the bizarre filename conventions on RISCOS, no port
242 to that platform is easy. Note that the new variable os.endsep is
243 silently supported in order to make life easier on this platform,
244 but we don't advertise it because it's not worth for most folks to
245 care about RISCOS portability.
246
Tim Peters25a9ce32001-02-19 07:06:36 +0000247
Tim Petersd7b5e882001-01-25 03:36:26 +0000248What's New in Python 2.1 alpha 2?
249=================================
Tim Peters40ead762001-01-27 05:35:26 +0000250
Tim Petersd7b5e882001-01-25 03:36:26 +0000251Core language, builtins, and interpreter
252
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000253- Scopes nest. If a name is used in a function or class, but is not
254 local, the definition in the nearest enclosing function scope will
255 be used. One consequence of this change is that lambda statements
256 could reference variables in the namespaces where the lambda is
257 defined. In some unusual cases, this change will break code.
258
259 In all previous version of Python, names were resolved in exactly
260 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000261 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000262 function A is defined within a function B, the names bound in B are
263 not visible in A. The new rules make names bound in B visible in A,
264 unless A contains a name binding that hides the binding in B.
265
266 Section 4.1 of the reference manual describes the new scoping rules
267 in detail. The test script in Lib/test/test_scope.py demonstrates
268 some of the effects of the change.
269
270 The new rules will cause existing code to break if it defines nested
271 functions where an outer function has local variables with the same
272 name as globals or builtins used by the inner function. Example:
273
274 def munge(str):
275 def helper(x):
276 return str(x)
277 if type(str) != type(''):
278 str = helper(str)
279 return str.strip()
280
281 Under the old rules, the name str in helper() is bound to the
282 builtin function str(). Under the new rules, it will be bound to
283 the argument named str and an error will occur when helper() is
284 called.
285
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000286- The compiler will report a SyntaxError if "from ... import *" occurs
287 in a function or class scope. The language reference has documented
288 that this case is illegal, but the compiler never checked for it.
289 The recent introduction of nested scope makes the meaning of this
290 form of name binding ambiguous. In a future release, the compiler
291 may allow this form when there is no possibility of ambiguity.
292
Tim Peters40ead762001-01-27 05:35:26 +0000293- repr(string) is easier to read, now using hex escapes instead of octal,
294 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
295
296 >>> "\texample \r\n" + chr(0) + chr(255)
297 '\texample \r\n\x00\xff' # in 2.1
298 '\011example \015\012\000\377' # in 2.0
299
Moshe Zadka6af0ce02001-01-29 06:41:00 +0000300- Functions are now compared and hashed by identity, not by value, since
301 the func_code attribute is writable.
302
Fred Drakefb9d7122001-02-01 20:00:40 +0000303- Weak references (PEP 205) have been added. This involves a few
304 changes in the core, an extension module (_weakref), and a Python
305 module (weakref). The weakref module is the public interface. It
306 includes support for "explicit" weak references, proxy objects, and
307 mappings with weakly held values.
308
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000309- A 'continue' statement can now appear in a try block within the body
310 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +0000311 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000312
Tim Petersd7b5e882001-01-25 03:36:26 +0000313Standard library
314
Barry Warsaw30dbd142001-01-31 22:14:01 +0000315- mailbox.py now has a new class, PortableUnixMailbox which is
316 identical to UnixMailbox but uses a more portable scheme for
317 determining From_ separators. Also, the constructors for all the
318 classes in this module have a new optional `factory' argument, which
319 is a callable used when new message classes must be instantiated by
320 the next() method.
321
Tim Petersd7b5e882001-01-25 03:36:26 +0000322- random.py is now self-contained, and offers all the functionality of
323 the now-deprecated whrandom.py. See the docs for details. random.py
324 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +0000325 and restoring the internal state of the generator; and jumpahead(n),
326 for quickly forcing the internal state to be the same as if n calls to
327 random() had been made. The latter is particularly useful for multi-
328 threaded programs, creating one instance of the random.Random() class for
329 each thread, then using .jumpahead() to force each instance to use a
330 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +0000331
Tim Peters0de88fc2001-02-01 04:59:18 +0000332- random.py's seed() function is new. For bit-for-bit compatibility with
333 prior releases, use the whseed function instead. The new seed function
334 addresses two problems: (1) The old function couldn't produce more than
335 about 2**24 distinct internal states; the new one about 2**45 (the best
336 that can be done in the Wichmann-Hill generator). (2) The old function
337 sometimes produced identical internal states when passed distinct
338 integers, and there was no simple way to predict when that would happen;
339 the new one guarantees to produce distinct internal states for all
340 arguments in [0, 27814431486576L).
341
Jeremy Hylton4c4fda02001-02-02 03:29:24 +0000342- The socket module now supports raw packets on Linux. The socket
343 family is AF_PACKET.
344
Tim Peters9ea17ac2001-02-02 05:57:15 +0000345- test_capi.py is a start at running tests of the Python C API. The tests
346 are implemented by the new Modules/_testmodule.c.
347
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000348- A new extension module, _symtable, provides provisional access to the
349 internal symbol table used by the Python compiler. A higher-level
350 interface will be added on top of _symtable in a future release.
351
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +0000352- Removed the obsolete soundex module.
353
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000354- xml.dom.minidom now uses the standard DOM exceptions. Node supports
355 the isSameNode method; NamedNodeMap the get method.
356
357- xml.sax.expatreader supports the lexical handler property; it
358 generates comment, startCDATA, and endCDATA events.
359
Tim Petersee826f82001-01-31 19:39:44 +0000360Windows changes
361
362- Build procedure: the zlib project is built in a different way that
363 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +0000364 the zlib binary used. See PCbuild\readme.txt for details. Your old
365 zlib-related directories can be deleted; you'll need to download fresh
366 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +0000367
Tim Peters9ea17ac2001-02-02 05:57:15 +0000368- Build: New subproject _test for the benefit of test_capi.py (see above).
369
Tim Petersb16c56f2001-02-02 21:24:51 +0000370- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
371 interface to some Python compiler internals).
372
373- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +0000374 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +0000375
Tim Petersa3a3a032000-11-30 05:22:44 +0000376What's New in Python 2.1 alpha 1?
377=================================
378
379Core language, builtins, and interpreter
380
Marc-André Lemburgebb195b2001-01-20 10:34:52 +0000381- There is a new Unicode companion to the PyObject_Str() API
382 called PyObject_Unicode(). It behaves in the same way as the
383 former, but assures that the returned value is an Unicode object
384 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +0000385
Guido van Rossumf98eda02001-01-17 15:54:45 +0000386- The comparison operators support "rich comparison overloading" (PEP
387 207). C extension types can provide a rich comparison function in
388 the new tp_richcompare slot in the type object. The cmp() function
389 and the C function PyObject_Compare() first try the new rich
390 comparison operators before trying the old 3-way comparison. There
391 is also a new C API PyObject_RichCompare() (which also falls back on
392 the old 3-way comparison, but does not constrain the outcome of the
393 rich comparison to a Boolean result).
394
395 The rich comparison function takes two objects (at least one of
396 which is guaranteed to have the type that provided the function) and
397 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
398 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
399 object, which may be NotImplemented (in which case the tp_compare
400 slot function is used as a fallback, if defined).
401
402 Classes can overload individual comparison operators by defining one
403 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +0000404 __ge__. There are no explicit "reflected argument" versions of
405 these; instead, __lt__ and __gt__ are each other's reflection,
406 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
407 reflection (similar at the C level). No other implications are
408 made; in particular, Python does not assume that == is the Boolean
409 inverse of !=, or that < is the Boolean inverse of >=. This makes
410 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +0000411
412 Classes or types that want to implement (in)equality tests but not
413 the ordering operators (i.e. unordered types) should implement ==
414 and !=, and raise an error for the ordering operators.
415
Guido van Rossuma88479f2001-01-18 14:28:08 +0000416 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +0000417 Boolean; e.g. a matrix type might want to return a matrix of bits
418 for A < B, giving elementwise comparisons. Such types should ensure
419 that any interpretation of their value in a Boolean context raises
420 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
421 at the C level) to always raise an exception.
422
Guido van Rossuma88479f2001-01-18 14:28:08 +0000423- Complex numbers use rich comparisons to define == and != but raise
424 an exception for <, <=, > and >=. Unfortunately, this also means
425 that cmp() of two complex numbers raises an exception when the two
426 numbers differ. Since it is not mathematically meaningful to compare
427 complex numbers except for equality, I hope that this doesn't break
428 too much code.
429
Tim Peters3389f192001-02-18 08:48:49 +0000430- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +0000431 not defined by the language, other than that it's arbitrary but
432 consistent (see the Reference Manual). An implementation detail changed
433 in 2.1a1 such that None now compares less than any other object. Code
434 relying on this new behavior (like code that relied on the previous
435 behavior) does so at its own risk.
436
Barry Warsaw573b5412001-01-15 20:43:18 +0000437- Functions and methods now support getting and setting arbitrarily
438 named attributes (PEP 232). Functions have a new __dict__
439 (a.k.a. func_dict) which hold the function attributes. Methods get
440 and set attributes on their underlying im_func. It is a TypeError
441 to set an attribute on a bound method.
442
Guido van Rossum051e3352001-01-15 19:11:10 +0000443- The xrange() object implementation has been improved so that
444 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
445 limitation that in this case len(xrange(sys.maxint)) can't be
446 calculated, but the common idiom "for i in xrange(sys.maxint)" will
447 work fine as long as the index i doesn't actually reach 2**31.
448 (Python uses regular ints for sequence and string indices; fixing
449 that is much more work.)
450
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000451- Two changes to from...import:
452
Guido van Rossumba381232001-02-03 15:06:40 +0000453 1) "from M import X" now works even if (after loading module M)
454 sys.modules['M'] is not a real module; it's basically a getattr()
455 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000456
457 2) "from M import *" now looks for M.__all__ to decide which names to
458 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
459 filters out names starting with '_' as before. Whether or not
460 __all__ exists, there's no restriction on the type of M.
461
Guido van Rossumf61f1662001-01-10 20:13:55 +0000462- File objects have a new method, xreadlines(). This is the fastest
463 way to iterate over all lines in a file:
464
465 for line in file.xreadlines():
466 ...do something to line...
467
468 See the xreadlines module (mentioned below) for how to do this for
469 other file-like objects.
470
471- Even if you don't use file.xreadlines(), you may expect a speedup on
472 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +0000473 quite a bit in platform-specific ways: on systems (like Linux) that
474 support flockfile(), getc_unlocked(), and funlockfile(), those are
475 used by default. On systems (like Windows) without getc_unlocked(),
476 a complicated (but still thread-safe) method using fgets() is used by
477 default.
478
Tim Petersd52269b2001-01-25 06:23:18 +0000479 You can force use of the fgets() method by #define'ing
480 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +0000481 getc_unlocked()).
482
Tim Petersd52269b2001-01-25 06:23:18 +0000483 You can force fgets() not to be used by #define'ing
484 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +0000485 test_bufio.py fails -- and let us know if it does!).
486
487- In addition, the fileinput module, while still slower than the other
488 methods on most platforms, has been sped up too, by using
489 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +0000490
491- Support for run-time warnings has been added, including a new
492 command line option (-W) to specify the disposition of warnings.
493 See the description of the warnings module below.
494
495- Extensive changes have been made to the coercion code. This mostly
496 affects extension modules (which can now implement mixed-type
497 numerical operators without having to use coercion), but
498 occasionally, in boundary cases the coercion semantics have changed
499 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +0000500 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +0000501 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +0000502 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +0000503
Guido van Rossumf98eda02001-01-17 15:54:45 +0000504- In connection with the coercion changes, a new built-in singleton
505 object, NotImplemented is defined. This can be returned for
506 operations that wish to indicate they are not implemented for a
507 particular combination of arguments. From C, this is
508 Py_NotImplemented.
509
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +0000510- The interpreter accepts now bytecode files on the command line even
511 if they do not have a .pyc or .pyo extension. On Linux, after executing
512
Martin v. Löwise214baa2001-02-04 22:37:56 +0000513import imp,sys,string
514magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
515reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
516open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +0000517
518 any byte code file can be used as an executable (i.e. as an argument
519 to execve(2)).
520
Tim Peters9940b802000-12-01 07:59:35 +0000521- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +0000522 character. In 1.6 and earlier, they never produced a sign,
523 and raised an error if the value of the long was too large
524 to fit in a Python int. In 2.0, they produced a sign if and
525 only if too large to fit in an int. This was inconsistent
526 across platforms (because the size of an int varies across
527 platforms), and inconsistent with hex() and oct(). Example:
528
529 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +0000530 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +0000531 'ffffffbe' # in 2.0 and before, on 32-bit machines
532 >>> hex(-0x42L)
533 '-0x42L' # in all versions of Python
534
Tim Peters9940b802000-12-01 07:59:35 +0000535 The behavior of %d formats for negative Python longs remains
536 the same as in 2.0 (although in 1.6 and before, they raised
537 an error if the long didn't fit in a Python int).
538
539 %u formats don't make sense for Python longs, but are allowed
540 and treated the same as %d in 2.1. In 2.0, a negative long
541 formatted via %u produced a sign if and only if too large to
542 fit in an int. In 1.6 and earlier, a negative long formatted
543 via %u raised an error if it was too big to fit in an int.
544
Guido van Rossum3661d392000-12-12 22:10:31 +0000545- Dictionary objects have an odd new method, popitem(). This removes
546 an arbitrary item from the dictionary and returns it (in the form of
547 a (key, value) pair). This can be useful for algorithms that use a
548 dictionary as a bag of "to do" items and repeatedly need to pick one
549 item. Such algorithms normally end up running in quadratic time;
550 using popitem() they can usually be made to run in linear time.
551
Tim Peters36cdad12000-12-29 02:06:45 +0000552Standard library
553
Thomas Woutersfe385252001-01-19 23:16:56 +0000554- In the time module, the time argument to the functions strftime,
555 localtime, gmtime, asctime and ctime is now optional, defaulting to
556 the current time (in the local timezone).
557
Guido van Rossumda91f222001-01-15 16:36:08 +0000558- The ftplib module now defaults to passive mode, which is deemed a
559 more useful default given that clients are often inside firewalls
560 these days. Note that this could break if ftplib is used to connect
561 to a *server* that is inside a firewall, from outside; this is
562 expected to be a very rare situation. To fix that, you can call
563 ftp.set_pasv(0).
564
Martin v. Löwis10a27872001-01-13 09:54:41 +0000565- The module site now treats .pth files not only for path configuration,
566 but also supports extensions to the initialization code: Lines starting
567 with import are executed.
568
Guido van Rossumf61f1662001-01-10 20:13:55 +0000569- There's a new module, warnings, which implements a mechanism for
570 issuing and filtering warnings. There are some new built-in
571 exceptions that serve as warning categories, and a new command line
572 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
573 turns warnings into errors). warnings.warn(message[, category])
574 issues a warning message; this can also be called from C as
575 PyErr_Warn(category, message).
576
577- A new module xreadlines was added. This exports a single factory
578 function, xreadlines(). The intention is that this code is the
579 absolutely fastest way to iterate over all lines in an open
580 file(-like) object:
581
582 import xreadlines
583 for line in xreadlines.xreadlines(file):
584 ...do something to line...
585
586 This is equivalent to the previous the speed record holder using
587 file.readlines(sizehint). Note that if file is a real file object
588 (as opposed to a file-like object), this is equivalent:
589
590 for line in file.xreadlines():
591 ...do something to line...
592
Tim Peters36cdad12000-12-29 02:06:45 +0000593- The bisect module has new functions bisect_left, insort_left,
594 bisect_right and insort_right. The old names bisect and insort
595 are now aliases for bisect_right and insort_right. XXX_right
596 and XXX_left methods differ in what happens when the new element
597 compares equal to one or more elements already in the list: the
598 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +0000599 right. Code that doesn't care where equal elements end up should
600 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +0000601
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +0000602- The new curses.panel module wraps the panel library that forms part
603 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
604
Guido van Rossumf61f1662001-01-10 20:13:55 +0000605- The SocketServer module now sets the allow_reuse_address flag by
606 default in the TCPServer class.
607
608- A new function, sys._getframe(), returns the stack frame pointer of
609 the caller. This is intended only as a building block for
610 higher-level mechanisms such as string interpolation.
611
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000612- The pyexpat module supports a number of new handlers, which are
613 available only in expat 1.2. If invocation of a callback fails, it
614 will report an additional frame in the traceback. Parser objects
615 participate now in garbage collection. If expat reports an unknown
616 encoding, pyexpat will try to use a Python codec; that works only
617 for single-byte charsets. The parser type objects is exposed as
618 XMLParserObject.
619
620- xml.dom now offers standard definitions for symbolic node type and
621 exception code constants, and a hierarchy of DOM exceptions. minidom
622 was adjusted to use them.
623
624- The conformance of xml.dom.minidom to the DOM specification was
625 improved. It detects a number of additional error cases; the
626 previous/next relationship works even when the tree is modified;
627 Node supports the normalize() method; NamedNodeMap, DocumentType and
628 DOMImplementation classes were added; Element supports the
629 hasAttribute and hasAttributeNS methods; and Text supports the splitText
630 method.
631
Guido van Rossumf61f1662001-01-10 20:13:55 +0000632Build issues
633
Guido van Rossum1e33bdc2001-01-23 03:17:00 +0000634- For Unix (and Unix-compatible) builds, configuration and building of
635 extension modules is now greatly automated. Rather than having to
636 edit the Modules/Setup file to indicate which modules should be
637 built and where their include files and libraries are, a
638 distutils-based setup.py script now takes care of building most
639 extension modules. All extension modules built this way are built
640 as shared libraries. Only a few modules that must be linked
641 statically are still listed in the Setup file; you won't need to
642 edit their configuration.
643
644- Python should now build out of the box on Cygwin. If it doesn't,
645 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +0000646
647- Python now always uses its own (renamed) implementation of getopt()
648 -- there's too much variation among C library getopt()
649 implementations.
650
651- C++ compilers are better supported; the CXX macro is always set to a
652 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +0000653
Tim Petersd92dfe02000-12-12 01:18:41 +0000654Windows changes
655
656- select module: By default under Windows, a select() call
657 can specify no more than 64 sockets. Python now boosts
658 this Microsoft default to 512. If you need even more than
659 that, see the MS docs (you'll need to #define FD_SETSIZE
660 and recompile Python from source).
661
Guido van Rossumf61f1662001-01-10 20:13:55 +0000662- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
663 subdirectory is no more!
664
Tim Petersa3a3a032000-11-30 05:22:44 +0000665
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000666What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +0000667=========================
Guido van Rossum61000331997-08-15 04:39:58 +0000668
Guido van Rossum8ed602b2000-09-01 22:34:33 +0000669Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000670changes are in the file HISTORY. If you are making the jump directly
671from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
672HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +0000673
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000674Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
675the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
676http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +0000677
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000678--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +0000679
680======================================================================
681
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000682What's new in 2.0 (since release candidate 1)?
683==============================================
684
685Standard library
686
687- The copy_reg module was modified to clarify its intended use: to
688 register pickle support for extension types, not for classes.
689 pickle() will raise a TypeError if it is passed a class.
690
691- Fixed a bug in gettext's "normalize and expand" code that prevented
692 it from finding an existing .mo file.
693
694- Restored support for HTTP/0.9 servers in httplib.
695
Tim Peters989b7b92000-10-16 20:24:53 +0000696- The math module was changed to stop raising OverflowError in case of
697 underflow, and return 0 instead in underflow cases. Whether Python
698 used to raise OverflowError in case of underflow was platform-
699 dependent (it did when the platform math library set errno to ERANGE
700 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000701
702- Fixed a bug in StringIO that occurred when the file position was not
703 at the end of the file and write() was called with enough data to
704 extend past the end of the file.
705
706- Fixed a bug that caused Tkinter error messages to get lost on
707 Windows. The bug was fixed by replacing direct use of
708 interp->result with Tcl_GetStringResult(interp).
709
710- Fixed bug in urllib2 that caused it to fail when it received an HTTP
711 redirect response.
712
713- Several changes were made to distutils: Some debugging code was
714 removed from util. Fixed the installer used when an external zip
715 program (like WinZip) is not found; the source code for this
716 installer is in Misc/distutils. check_lib() was modified to behave
717 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
718 test for whether installed modules are on sys.path was changed to
719 use both normcase() and normpath().
720
Jeremy Hyltond867a2c2000-10-16 20:41:38 +0000721- Several minor bugs were fixed in the xml package (the minidom,
722 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000723
724- The regression test driver (regrtest.py) behavior when invoked with
725 -l changed: It now reports a count of objects that are recognized as
726 garbage but not freed by the garbage collector.
727
Tim Peters989b7b92000-10-16 20:24:53 +0000728- The regression test for the math module was changed to test
729 exceptional behavior when the test is run in verbose mode. Python
730 cannot yet guarantee consistent exception behavior across platforms,
731 so the exception part of test_math is run only in verbose mode, and
732 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000733
734Internals
735
736- PyOS_CheckStack() has been disabled on Win64, where it caused
737 test_sre to fail.
738
739Build issues
740
741- Changed compiler flags, so that gcc is always invoked with -Wall and
742 -Wstrict-prototypes. Users compiling Python with GCC should see
743 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +0000744 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +0000745 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000746
Tim Petersa3a3a032000-11-30 05:22:44 +0000747- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000748
749Tools and other miscellany
750
751- The compiler in Tools/compiler was updated to support the new
752 language features introduced in 2.0: extended print statement, list
753 comprehensions, and augmented assignments. The new compiler should
754 also be backwards compatible with Python 1.5.2; the compiler will
755 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +0000756 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000757
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000758What's new in 2.0 release candidate 1 (since beta 2)?
759=====================================================
760
Jeremy Hylton6040aaa2000-10-09 21:27:22 +0000761What is release candidate 1?
762
763We believe that release candidate 1 will fix all known bugs that we
764intend to fix for the 2.0 final release. This release should be a bit
765more stable than the previous betas. We would like to see even more
766widespread testing before the final release, so we are producing this
767release candidate. The final release will be exactly the same unless
768any show-stopping (or brown bag) bugs are found by testers of the
769release candidate.
770
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000771All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000772to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000773
774Core language, builtins, and interpreter
775
776- A bug that caused crashes when __coerce__ was used with augmented
777 assignment, e.g. +=, was fixed.
778
779- Raise ZeroDivisionError when raising zero to a negative number,
780 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
781 power operator and the result of math.pow(0.0, -2.0) will vary by
782 platform. On Linux, it raises a ValueError.
783
784- A bug in Unicode string interpolation was fixed that occasionally
785 caused errors with formats including "%%". For example, the
786 following expression "%% %s" % u"abc" no longer raises a TypeError.
787
788- Compilation of deeply nested expressions raises MemoryError instead
789 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
790
791- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
792 rendering them useless. They are now written in binary mode again.
793
794Standard library
795
796- Keyword arguments are now accepted for most pattern and match object
797 methods in SRE, the standard regular expression engine.
798
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000799- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +0000800 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000801
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000802- Several bugs in the Unicode handling and error handling in _tkinter
803 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000804
805- Fix memory management errors in Merge() and Tkapp_Call() routines.
806
807- Several changes were made to cStringIO to make it compatible with
808 the file-like object interface and with StringIO. If operations are
809 performed on a closed object, an exception is raised. The truncate
810 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +0000811 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000812
813- There were many changes made to the linuxaudiodev module and its
814 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +0000815 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000816
817 Note that this module is named poorly, because it should work
818 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +0000819 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000820
821 The module now raises exceptions when errors occur instead of
822 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
823 audio) and defines a getptr() method that calls the
824 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
825
826- The library_version attribute, introduced in an earlier beta, was
827 removed because it can not be supported with early versions of the C
828 readline library, which provides no way to determine the version at
829 compile-time.
830
831- The binascii module is now enabled on Win64.
832
Tim Peters46446d62000-10-09 21:19:31 +0000833- tokenize.py no longer suffers "recursion depth" errors when parsing
834 programs with very long string literals.
835
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000836Internals
837
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000838- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000839 which is called when the interpreter starts up to determine where
840 the standard library is installed. These vulnerabilities affect all
841 previous versions of Python and can be exploited by setting very
842 long values for PYTHONHOME or argv[0]. The risk is greatest for a
843 setuid Python script, although use of the wrapper in
844 Misc/setuid-prog.c will eliminate the vulnerability.
845
846- Fixed garbage collection bugs in instance creation that were
847 triggered when errors occurred during initialization. The solution,
848 applied in cPickle and in PyInstance_New(), is to call
849 PyObject_GC_Init() after the initialization of the object's
850 container attributes is complete.
851
852- pyexpat adds definitions of PyModule_AddStringConstant and
853 PyModule_AddObject if the Python version is less than 2.0, which
854 provides compatibility with PyXML on Python 1.5.2.
855
856- If the platform has a bogus definition for LONG_BIT (the number of
857 bits in a long), an error will be reported at compile time.
858
859- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
860 collection crashes and possibly other, unreported crashes.
861
862- Fixed a memory leak in _PyUnicode_Fini().
863
864Build issues
865
866- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000867 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +0000868 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000869
870- The mmap.PAGESIZE constant is now initialized using sysconf when
871 possible, which eliminates a dependency on -lucb for Reliant UNIX.
872
873- The md5 file should now compile on all platforms.
874
875- The select module now compiles on platforms that do not define
876 POLLRDNORM and related constants.
877
878- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +0000879 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000880
Jeremy Hylton10921202000-10-09 18:34:12 +0000881- BeOS: A number of changes were made to the build and installation
882 process. ar-fake now operates on a directory of object files.
883 dl_export.h is gone, and its macros now appear on the mwcc command
884 line during build on PPC BeOS.
885
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000886- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +0000887 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000888
889- Cygwin: Support for shared libraries, Tkinter, and sockets.
890
891- SunOS 4.1.4_JL: Fix test for directory existence in configure.
892
893Tools and other miscellany
894
895- Removed debugging prints from main used with freeze.
896
Tim Peters46446d62000-10-09 21:19:31 +0000897- IDLE auto-indent no longer crashes when it encounters Unicode
898 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000899
900What's new in 2.0 beta 2 (since beta 1)?
901========================================
902
903Core language, builtins, and interpreter
904
Tim Peters482c0212000-09-26 06:33:09 +0000905- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000906 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +0000907
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000908- Add -h and -V command line options to print the usage message and
909 Python version number and exit immediately.
910
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +0000911- eval() and exec accept Unicode objects as code parameters.
912
913- getattr() and setattr() now also accept Unicode objects for the
914 attribute name, which are converted to strings using the default
915 encoding before lookup.
916
917- Multiplication on string and Unicode now does proper bounds
918 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
919 string is too long."
920
921- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +0000922 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +0000923
Jeremy Hylton1b618592000-09-26 05:32:36 +0000924
925Standard library and extensions
926
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000927- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +0000928 argument checking; it still takes no arguments.
929
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000930- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000931
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000932- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000933
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000934- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +0000935
936- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000937 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000938
939- copy: Copy Unicode objects atomically.
940
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000941- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000942
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000943- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000944
Fred Drake67233bc2000-09-26 16:40:27 +0000945- dbm: Add get() and setdefault() methods to dbm object. Add constant
946 `library' to module that names the library used. Added doc strings
947 and method names to error messages. Uses configure to determine
948 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
949 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000950
951- distutils: Update to version 0.9.3.
952
953- dl: Add several dl.RTLD_ constants.
954
955- fpectl: Now supported on FreeBSD.
956
957- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
958 found by the collector will be saved in gc.garbage. This is useful
959 for debugging a program that creates reference cycles.
960
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000961- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +0000962 of HTTP class. Do not close socket on zero-length response. Do not
963 crash when server sends invalid content-length header.
964
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000965- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000966
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +0000967- marshal: When reading a short, sign-extend on platforms where shorts
968 are bigger than 16 bits. When reading a long, repair the unportable
969 sign extension that was being done for 64-bit machines. (It assumed
970 that signed right shift sign-extends.)
971
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000972- operator: Add contains(), invert(), __invert__() as aliases for
973 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000974
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000975- os: Add support for popen2() and popen3() on all platforms where
976 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +0000977
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000978- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +0000979 clicking on a file in Explorer (or passing the file name to the
980 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +0000981
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000982- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +0000983 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +0000984
985- pickle: Now raises ValueError when an invalid pickle that contains
986 a non-string repr where a string repr was expected. This behavior
987 matches cPickle.
988
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000989- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000990
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000991- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000992
993- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +0000994 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000995 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +0000996
997- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000998 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000999
1000- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00001001 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00001002 few cycles during startup since the first call to
1003 setdefaultencoding() will initialize the codec registry and the
1004 encodings package.
1005
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001006- socket: Support for size hint in readlines() method of object returned
1007 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001008
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001009- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001010 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001011 is followed by whitespace.
1012
Tim Petersa3a3a032000-11-30 05:22:44 +00001013- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001014
1015- struct: Check ranges for bytes and shorts.
1016
1017- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001018 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001019
1020- Tkinter: Image objects are now guaranteed to have unique ids. Set
1021 event.delta to zero if Tk version doesn't support mousewheel.
1022 Removed some debugging prints.
1023
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001024- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001025
Fred Drake67233bc2000-09-26 16:40:27 +00001026- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001027 which works around a bug in Norton AntiVirus 2000 that leads directly
1028 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001029
1030- xml: New version detection code allows PyXML to override standard
1031 XML package if PyXML version is greater than 0.6.1.
1032
Fred Drake64bb3802000-09-26 16:21:35 +00001033- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
1034 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
1035 tree only for nodes which are sufficiently interesting to a specific
1036 application. Does not provide the HTML-specific extensions. Still
1037 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001038
Fred Drake64bb3802000-09-26 16:21:35 +00001039- xml.sax: SAX 2 support for Python, including all the handler
1040 interfaces needed to process XML 1.0 compliant XML. Some
1041 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001042
Fred Drake64bb3802000-09-26 16:21:35 +00001043- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
1044 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001045
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001046
Jeremy Hylton1b618592000-09-26 05:32:36 +00001047C API
1048
1049- Add three new convenience functions for module initialization --
1050 PyModule_AddObject(), PyModule_AddIntConstant(), and
1051 PyModule_AddStringConstant().
1052
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001053- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00001054 removed and add #error to Python.h if NULL isn't defined after
1055 #include of stdio.h.
1056
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001057- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00001058 backwards compatibility (at the source level) with old extensions.
1059
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001060- A wrapper API was added for signal() and sigaction(). Instead of
1061 either function, always use PyOS_getsig() to get a signal handler
1062 and PyOS_setsig() to set one. A new convenience typedef
1063 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001064
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001065- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00001066 internal data buffer and size of a string object -- or the default
1067 encoded version of a Unicode object.
1068
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001069- PyString_Size() and PyString_AsString() accept Unicode objects.
1070
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001071- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00001072 exists). INT_MAX and LONG_MAX will always be defined, even if
1073 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001074
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001075- PyFloat_FromString takes a second argument, pend, that was
1076 effectively useless. It is now officially useless but preserved for
1077 backwards compatibility. If the pend argument is not NULL, *pend is
1078 set to NULL.
1079
1080- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
1081 for the attribute name. See note on getattr() above.
1082
1083- A few bug fixes to argument processing for Unicode.
1084 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
1085 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
1086 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00001087 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001088
1089- Py_BuildValue accepts B format (for bgen-generated code).
1090
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001091
Jeremy Hylton1b618592000-09-26 05:32:36 +00001092Internals
1093
1094- On Unix, fix code for finding Python installation directory so that
1095 it works when argv[0] is a relative path.
1096
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00001097- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001098 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00001099 rather than by generating a copy of the object.
1100
Tim Peters482c0212000-09-26 06:33:09 +00001101- Several of the internal Unicode tables are much smaller now, and
1102 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001103
Jeremy Hylton97693b02000-09-26 17:42:51 +00001104- In the garbage collector: Fixed bug in collection of tuples. Fixed
1105 bug that caused some instances to be removed from the container set
1106 while they were still live. Fixed parsing in gc.set_debug() for
1107 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001108
1109- Fixed refcount problem in instance deallocation that only occurred
1110 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
1111
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001112- On Windows, getpythonregpath is now protected against null data in
1113 registry key.
1114
1115- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00001116 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001117
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001118
Jeremy Hylton1b618592000-09-26 05:32:36 +00001119Build and platform-specific issues
1120
1121- Better support of GNU Pth via --with-pth configure option.
1122
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001123- Python/C API now properly exposed to dynamically-loaded extension
1124 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001125
1126- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
1127 Don't define MS_SYNC to be zero when it is undefined. Added missing
1128 prototypes in posixmodule.c.
1129
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001130- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001131 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001132
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001133- Fix largefile support on older NetBSD systems and OpenBSD by adding
1134 define for TELL64.
1135
1136
1137Tools and other miscellany
1138
1139- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
1140
1141- freeze: The modulefinder now works with 2.0 opcodes.
1142
Tim Petersa3a3a032000-11-30 05:22:44 +00001143- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001144 Move hackery of sys.argv until after the Tk instance has been
1145 created, which allows the application-specific Tkinter
1146 initialization to be executed if present; also pass an explicit
1147 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00001148
Jeremy Hylton1b618592000-09-26 05:32:36 +00001149
1150What's new in 2.0 beta 1?
1151=========================
1152
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001153Source Incompatibilities
1154------------------------
1155
1156None. Note that 1.6 introduced several incompatibilities with 1.5.2,
1157such as single-argument append(), connect() and bind(), and changes to
1158str(long) and repr(float).
1159
1160
1161Binary Incompatibilities
1162------------------------
1163
1164- Third party extensions built for Python 1.5.x or 1.6 cannot be used
1165with Python 2.0; these extensions will have to be rebuilt for Python
11662.0.
1167
1168- On Windows, attempting to import a third party extension built for
1169Python 1.5.x or 1.6 results in an immediate crash; there's not much we
1170can do about this. Check your PYTHONPATH environment variable!
1171
1172- Python bytecode files (*.pyc and *.pyo) are not compatible between
1173releases.
1174
1175
1176Overview of Changes Since 1.6
1177-----------------------------
1178
1179There are many new modules (including brand new XML support through
1180the xml package, and i18n support through the gettext module); a list
1181of all new modules is included below. Lots of bugs have been fixed.
1182
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001183The process for making major new changes to the language has changed
1184since Python 1.6. Enhancements must now be documented by a Python
1185Enhancement Proposal (PEP) before they can be accepted.
1186
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001187There are several important syntax enhancements, described in more
1188detail below:
1189
1190 - Augmented assignment, e.g. x += 1
1191
1192 - List comprehensions, e.g. [x**2 for x in range(10)]
1193
1194 - Extended import statement, e.g. import Module as Name
1195
1196 - Extended print statement, e.g. print >> file, "Hello"
1197
1198Other important changes:
1199
1200 - Optional collection of cyclical garbage
1201
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001202Python Enhancement Proposal (PEP)
1203---------------------------------
1204
1205PEP stands for Python Enhancement Proposal. A PEP is a design
1206document providing information to the Python community, or describing
1207a new feature for Python. The PEP should provide a concise technical
1208specification of the feature and a rationale for the feature.
1209
1210We intend PEPs to be the primary mechanisms for proposing new
1211features, for collecting community input on an issue, and for
1212documenting the design decisions that have gone into Python. The PEP
1213author is responsible for building consensus within the community and
1214documenting dissenting opinions.
1215
1216The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001217
1218Augmented Assignment
1219--------------------
1220
1221This must have been the most-requested feature of the past years!
1222Eleven new assignment operators were added:
1223
Guido van Rossume905e952000-09-05 12:42:46 +00001224 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001225
1226For example,
1227
1228 A += B
1229
1230is similar to
1231
1232 A = A + B
1233
1234except that A is evaluated only once (relevant when A is something
1235like dict[index].attr).
1236
1237However, if A is a mutable object, A may be modified in place. Thus,
1238if A is a number or a string, A += B has the same effect as A = A+B
1239(except A is only evaluated once); but if a is a list, A += B has the
1240same effect as A.extend(B)!
1241
1242Classes and built-in object types can override the new operators in
1243order to implement the in-place behavior; the not-in-place behavior is
1244used automatically as a fallback when an object doesn't implement the
1245in-place behavior. For classes, the method name is derived from the
1246method name for the corresponding not-in-place operator by inserting
1247an 'i' in front of the name, e.g. __iadd__ implements in-place
1248__add__.
1249
1250Augmented assignment was implemented by Thomas Wouters.
1251
1252
1253List Comprehensions
1254-------------------
1255
1256This is a flexible new notation for lists whose elements are computed
1257from another list (or lists). The simplest form is:
1258
1259 [<expression> for <variable> in <sequence>]
1260
Guido van Rossum56db0952000-09-06 23:34:25 +00001261For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001262This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001263
1264You can also add a condition:
1265
1266 [<expression> for <variable> in <sequence> if <condition>]
1267
1268For example, [w for w in words if w == w.lower()] would yield the list
1269of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001270than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001271
1272You can also have nested for loops and more than one 'if' clause. For
1273example, here's a function that flattens a sequence of sequences::
1274
1275 def flatten(seq):
1276 return [x for subseq in seq for x in subseq]
1277
1278 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
1279
1280This prints
1281
1282 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
1283
1284List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001285Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001286
1287
1288Extended Import Statement
1289-------------------------
1290
1291Many people have asked for a way to import a module under a different
1292name. This can be accomplished like this:
1293
1294 import foo
1295 bar = foo
1296 del foo
1297
1298but this common idiom gets old quickly. A simple extension of the
1299import statement now allows this to be written as follows:
1300
1301 import foo as bar
1302
1303There's also a variant for 'from ... import':
1304
1305 from foo import bar as spam
1306
1307This also works with packages; e.g. you can write this:
1308
1309 import test.regrtest as regrtest
1310
1311Note that 'as' is not a new keyword -- it is recognized only in this
1312context (this is only possible because the syntax for the import
1313statement doesn't involve expressions).
1314
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001315Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001316
1317
1318Extended Print Statement
1319------------------------
1320
1321Easily the most controversial new feature, this extension to the print
1322statement adds an option to make the output go to a different file
1323than the default sys.stdout.
1324
1325For example, to write an error message to sys.stderr, you can now
1326write:
1327
1328 print >> sys.stderr, "Error: bad dog!"
1329
1330As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00001331evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001332
1333 print >> None, "Hello world"
1334
1335is equivalent to
1336
1337 print "Hello world"
1338
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001339Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001340
1341
1342Optional Collection of Cyclical Garbage
1343---------------------------------------
1344
1345Python is now equipped with a garbage collector that can hunt down
1346cyclical references between Python objects. It's no replacement for
1347reference counting; in fact, it depends on the reference counts being
1348correct, and decides that a set of objects belong to a cycle if all
1349their reference counts can be accounted for from their references to
1350each other. This devious scheme was first proposed by Eric Tiedemann,
1351and brought to implementation by Neil Schemenauer.
1352
1353There's a module "gc" that lets you control some parameters of the
1354garbage collection. There's also an option to the configure script
1355that lets you enable or disable the garbage collection. In 2.0b1,
1356it's on by default, so that we (hopefully) can collect decent user
1357experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00001358performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001359off by default in the final 2.0 release.
1360
1361
1362Smaller Changes
1363---------------
1364
1365A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
1366map(None, seq1, seq2, ...) when the sequences have the same length;
1367i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
1368the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001369zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001370
1371sys.version_info is a tuple (major, minor, micro, level, serial).
1372
1373Dictionaries have an odd new method, setdefault(key, default).
1374dict.setdefault(key, default) returns dict[key] if it exists; if not,
1375it sets dict[key] to default and returns that value. Thus:
1376
1377 dict.setdefault(key, []).append(item)
1378
1379does the same work as this common idiom:
1380
1381 if not dict.has_key(key):
1382 dict[key] = []
1383 dict[key].append(item)
1384
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001385There are two new variants of SyntaxError that are raised for
1386indentation-related errors: IndentationError and TabError.
1387
1388Changed \x to consume exactly two hex digits; see PEP 223. Added \U
1389escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001390
1391The limits on the size of expressions and file in Python source code
1392have been raised from 2**16 to 2**32. Previous versions of Python
1393were limited because the maximum argument size the Python VM accepted
1394was 2**16. This limited the size of object constructor expressions,
1395e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
1396limit was raised thanks to a patch by Charles Waldman that effectively
1397fixes the problem. It is now much more likely that you will be
1398limited by available memory than by an arbitrary limit in Python.
1399
1400The interpreter's maximum recursion depth can be modified by Python
1401programs using sys.getrecursionlimit and sys.setrecursionlimit. This
1402limit is the maximum number of recursive calls that can be made by
1403Python code. The limit exists to prevent infinite recursion from
1404overflowing the C stack and causing a core dump. The default value is
14051000. The maximum safe value for a particular platform can be found
1406by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001407
1408New Modules and Packages
1409------------------------
1410
1411atexit - for registering functions to be called when Python exits.
1412
1413imputil - Greg Stein's alternative API for writing custom import
1414hooks.
1415
1416pyexpat - an interface to the Expat XML parser, contributed by Paul
1417Prescod.
1418
1419xml - a new package with XML support code organized (so far) in three
1420subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
1421would fill a volume. There's a special feature whereby a
1422user-installed package named _xmlplus overrides the standard
1423xmlpackage; this is intended to give the XML SIG a hook to distribute
1424backwards-compatible updates to the standard xml package.
1425
1426webbrowser - a platform-independent API to launch a web browser.
1427
1428
Guido van Rossume905e952000-09-05 12:42:46 +00001429Changed Modules
1430---------------
1431
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001432array -- new methods for array objects: count, extend, index, pop, and
1433remove
1434
1435binascii -- new functions b2a_hex and a2b_hex that convert between
1436binary data and its hex representation
1437
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001438calendar -- Many new functions that support features including control
1439over which day of the week is the first day, returning strings instead
1440of printing them. Also new symbolic constants for days of week,
1441e.g. MONDAY, ..., SUNDAY.
1442
1443cgi -- FieldStorage objects have a getvalue method that works like a
1444dictionary's get method and returns the value attribute of the object.
1445
1446ConfigParser -- The parser object has new methods has_option,
1447remove_section, remove_option, set, and write. They allow the module
1448to be used for writing config files as well as reading them.
1449
1450ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00001451optionally support the RFC 959 REST command.
1452
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001453gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00001454
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001455httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
1456the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00001457
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001458locale -- implement getdefaultlocale for Win32 and Macintosh
1459
1460marshal -- no longer dumps core when marshaling deeply nested or
1461recursive data structures
1462
1463os -- new functions isatty, seteuid, setegid, setreuid, setregid
1464
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001465os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
1466support under Unix.
1467
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001468os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001469
1470os.path -- fix semantics of os.path.commonprefix
1471
1472smtplib -- support for sending very long messages
1473
1474socket -- new function getfqdn()
1475
1476readline -- new functions to read, write and truncate history files.
1477The readline section of the library reference manual contains an
1478example.
1479
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001480select -- add interface to poll system call
1481
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001482shutil -- new copyfileobj function
1483
1484SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
1485HTTP server.
1486
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001487Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001488
1489urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00001490e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001491
1492whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00001493
1494
1495Obsolete Modules
1496----------------
1497
1498None. However note that 1.6 made a whole slew of modules obsolete:
1499stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
1500poly, zmod, strop, util, whatsound.
1501
1502
1503Changed, New, Obsolete Tools
1504----------------------------
1505
Tim Peters8b092332000-09-05 20:15:25 +00001506None.
Guido van Rossume905e952000-09-05 12:42:46 +00001507
1508
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001509C-level Changes
1510---------------
1511
1512Several cleanup jobs were carried out throughout the source code.
1513
1514All C code was converted to ANSI C; we got rid of all uses of the
1515Py_PROTO() macro, which makes the header files a lot more readable.
1516
1517Most of the portability hacks were moved to a new header file,
1518pyport.h; several other new header files were added and some old
1519header files were removed, in an attempt to create a more rational set
1520of header files. (Few of these ever need to be included explicitly;
1521they are all included by Python.h.)
1522
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001523Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001524and Win64, especially for the new Intel Itanium processor. Mick also
1525added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001526
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001527The C APIs to return an object's size have been update to consistently
1528use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
1529previous versions, the abstract interfaces used PyXXX_Length and the
1530concrete interfaces used PyXXX_Size. The old names,
1531e.g. PyObject_Length, are still available for backwards compatibility
1532at the API level, but are deprecated.
1533
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001534The PyOS_CheckStack function has been implemented on Windows by
1535Fredrik Lundh. It prevents Python from failing with a stack overflow
1536on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001537
1538The GC changes resulted in creation of two new slots on object,
1539tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00001540the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001541
1542The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00001543C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001544
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001545PyErr_Format has been updated to automatically calculate the size of
1546the buffer needed to hold the formatted result string. This change
1547prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001548
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001549New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00001550
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001551PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
1552that are the same as their non-Ex counterparts except they take an
1553extra flag argument that tells them to close the file when done.
1554
1555XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00001556
Tim Peters8b092332000-09-05 20:15:25 +00001557
1558Windows Changes
1559---------------
1560
1561New popen2/popen3/peopen4 in os module (see Changed Modules above).
1562
1563os.popen is much more usable on Windows 95 and 98. See Microsoft
1564Knowledge Base article Q150956. The Win9x workaround described there
1565is implemented by the new w9xpopen.exe helper in the root of your
1566Python installation. Note that Python uses this internally; it is not
1567a standalone program.
1568
1569Administrator privileges are no longer required to install Python
1570on Windows NT or Windows 2000. If you have administrator privileges,
1571Python's registry info will be written under HKEY_LOCAL_MACHINE.
1572Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00001573under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00001574uses of Python, but will prevent some advanced uses from working
1575(for example, running a Python script as an NT service, or possibly
1576from CGI).
1577
1578[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
1579installer; instead, it installs the needed Tcl/Tk files directly in the
1580Python directory. If you already have a Tcl/Tk installation, this
1581wastes some disk space (about 4 Megs) but avoids problems with
1582conflicting Tcl/Tk installations, and makes it much easier for Python
1583to ensure that Tcl/Tk can find all its files.
1584
1585[This was new in 1.6] The Windows installer now installs by default in
1586\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
1587
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001588
1589Updates to the changes between 1.5.2 and 1.6
1590--------------------------------------------
1591
1592The 1.6 NEWS file can't be changed after the release is done, so here
1593is some late-breaking news:
1594
1595New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
1596and changes to getlocale() and setlocale().
1597
1598The new module is now enabled per default.
1599
1600It is not true that the encodings codecs cannot be used for normal
1601strings: the string.encode() (which is also present on 8-bit strings
1602!) allows using them for 8-bit strings too, e.g. to convert files from
1603cp1252 (Windows) to latin-1 or vice-versa.
1604
1605Japanese codecs are available from Tamito KAJIYAMA:
1606http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
1607
1608
Guido van Rossumab9d6f01998-08-10 22:01:13 +00001609======================================================================