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Martin v. Löwis0411f6f2001-03-21 08:01:39 +00001What's New in Python 2.1 beta 2?
2================================
3
Guido van Rossum053ae352001-03-22 14:17:21 +00004(Unlisted are many fixed bugs, more documentation, etc.)
5
Martin v. Löwis0411f6f2001-03-21 08:01:39 +00006Core language, builtins, and interpreter
7
Guido van Rossum053ae352001-03-22 14:17:21 +00008- The nested scopes work (enabled by "from __future__ import
9 nested_scopes") is completed; in particular, the future now extends
10 into code executed through exec, eval() and execfile(), and into the
11 interactive interpreter.
12
13- When calling a base class method (e.g. BaseClass.__init__(self)),
14 this is now allowed even if self is not strictly spoken a class
15 instance (e.g. when using metaclasses or the Don Beaudry hook).
16
17- Slice objects are now comparable but not hashable; this prevents
18 dict[:] from being accepted but meaningless.
19
20- Complex division is now calculated using less braindead algorithms.
21 This doesn't change semantics except it's more likely to give useful
22 results in extreme cases. Complex repr() now uses full precision
23 like float repr().
24
25- sgmllib.py now calls handle_decl() for simple <!...> declarations.
26
Jeremy Hyltonf626db72001-03-23 14:18:27 +000027- It is illegal to assign to the name __debug__, which is set when the
28 interpreter starts. It is effectively a compile-time constant.
29
30- A warning will be issued if a global statement for a variable
31 follows a use or assignment of that variable.
32
Martin v. Löwis0411f6f2001-03-21 08:01:39 +000033Standard library
34
Guido van Rossum053ae352001-03-22 14:17:21 +000035- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
36 inspired by JUnit), is now part of the standard library. You now
37 have a choice of two testing frameworks: unittest requires you to
38 write testcases as separate code, doctest gathers them from
39 docstrings. Both approaches have their advantages and
40 disadvantages.
41
42- A new module Tix was added, which wraps the Tix extension library
43 for Tk. With that module, it is not necessary to statically link
44 Tix with _tkinter, since Tix will be loaded with Tcl's "package
45 require" command. See Demo/tix/.
46
47- tzparse.py is now obsolete.
48
49- In gzip.py, the seek() and tell() methods are removed -- they were
50 non-functional anyway, and it's better if callers can test for their
51 existence with hasattr().
52
53Python/C API
54
55- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
56 that's already in the dictionary during a PyDict_Next() iteration.
57 This used to fail occasionally when a dictionary resize operation
58 could be triggered that would rehash all the keys. All other
59 modifications to the dictionary are still off-limits during a
60 PyDict_Next() iteration!
61
62- New extended APIs related to passing compiler variables around.
63
64- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
65 implement isinstance() and issubclass().
66
67- Py_BuildValue() now has a "D" conversion to create a Python complex
68 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +000069
Fred Drake4e262a92001-03-22 18:26:47 +000070- Extensions types which support weak references must now set the
71 field allocated for the weak reference machinery to NULL themselves;
72 this is done to avoid the cost of checking each object for having a
73 weakly referencable type in PyObject_INIT(), since most types are
74 not weakly referencable.
75
Jeremy Hyltonf626db72001-03-23 14:18:27 +000076- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
77 free variables and cell variables to and from the frame's f_locals.
78
79- Variants of several functions defined in pythonrun.h have been added
80 to support the nested_scopes future statement. The variants all end
81 in Flags and take an extra argument, a PyCompilerFlags *; examples:
82 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
83 variants may be removed in Python 2.2, when nested scopes are
84 mandatory.
85
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +000086Distutils
87
88- the sdist command now writes a PKG-INFO file, as described in PEP 241,
89 into the release tree.
90
91- several enhancements to the bdist_wininst command from Thomas Heller
92 (an uninstaller, more customization of the installer's display)
93
94- from Jack Jansen: added Mac-specific code to generate a dialog for
95 users to specify the command-line (because providing a command-line with
96 MacPython is awkward). Jack also made various fixes for the Mac
97 and the Metrowerks compiler.
98
99- added 'platforms' and 'keywords' to the set of metadata that can be
Andrew M. Kuchling68ad64a2001-03-31 02:42:42 +0000100 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000101
102- applied patches from Jason Tishler to make the compiler class work with
103 Cygwin.
104
105
Tim Peters2fe289a2001-03-01 22:19:38 +0000106What's New in Python 2.1 beta 1?
107================================
Tim Petersd66595f2001-02-04 03:09:53 +0000108
109Core language, builtins, and interpreter
110
Guido van Rossum9d0fbde2001-03-02 14:00:32 +0000111- Following an outcry from the community about the amount of code
112 broken by the nested scopes feature introduced in 2.1a2, we decided
113 to make this feature optional, and to wait until Python 2.2 (or at
114 least 6 months) to make it standard. The option can be enabled on a
115 per-module basis by adding "from __future__ import nested_scopes" at
116 the beginning of a module (before any other statements, but after
117 comments and an optional docstring). See PEP 236 (Back to the
118 __future__) for a description of the __future__ statement. PEP 227
119 (Statically Nested Scopes) has been updated to reflect this change,
120 and to clarify the semantics in a number of endcases.
121
122- The nested scopes code, when enabled, has been hardened, and most
123 bugs and memory leaks in it have been fixed.
124
125- Compile-time warnings are now generated for a number of conditions
126 that will break or change in meaning when nested scopes are enabled:
127
128 - Using "from...import *" or "exec" without in-clause in a function
129 scope that also defines a lambda or nested function with one or
130 more free (non-local) variables. The presence of the import* or
131 bare exec makes it impossible for the compiler to determine the
132 exact set of local variables in the outer scope, which makes it
133 impossible to determine the bindings for free variables in the
134 inner scope. To avoid the warning about import *, change it into
135 an import of explicitly name object, or move the import* statement
136 to the global scope; to avoid the warning about bare exec, use
137 exec...in... (a good idea anyway -- there's a possibility that
138 bare exec will be deprecated in the future).
139
140 - Use of a global variable in a nested scope with the same name as a
141 local variable in a surrounding scope. This will change in
142 meaning with nested scopes: the name in the inner scope will
143 reference the variable in the outer scope rather than the global
144 of the same name. To avoid the warning, either rename the outer
145 variable, or use a global statement in the inner function.
146
Neil Schemenauera35c6882001-02-27 04:45:05 +0000147- An optional object allocator has been included. This allocator is
148 optimized for Python objects and should be faster and use less memory
149 than the standard system allocator. It is not enabled by default
150 because of possible thread safety problems. The allocator is only
151 protected by the Python interpreter lock and it is possible that some
152 extension modules require a thread safe allocator. The object
153 allocator can be enabled by providing the "--with-pymalloc" option to
154 configure.
155
Tim Petersd66595f2001-02-04 03:09:53 +0000156Standard library
157
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000158- pyexpat now detects the expat version if expat.h defines it. A
159 number of additional handlers are provided, which are only available
160 since expat 1.95. In addition, the methods SetParamEntityParsing and
161 GetInputContext of Parser objects are available with 1.95.x
162 only. Parser objects now provide the ordered_attributes and
163 specified_attributes attributes. A new module expat.model was added,
164 which offers a number of additional constants if 1.95.x is used.
165
166- xml.dom offers the new functions registerDOMImplementation and
167 getDOMImplementation.
168
169- xml.dom.minidom offers a toprettyxml method. A number of DOM
170 conformance issues have been resolved. In particular, Element now
171 has an hasAttributes method, and the handling of namespaces was
172 improved.
173
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000174- Ka-Ping Yee contributed two new modules: inspect.py, a module for
175 getting information about live Python code, and pydoc.py, a module
176 for interactively converting docstrings to HTML or text.
177 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +0000178 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +0000179 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
180 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000181
Tim Peters1eff7962001-03-01 02:31:33 +0000182- New library module difflib.py, primarily packaging the SequenceMatcher
183 class at the heart of the popular ndiff.py file-comparison tool.
184
185- doctest.py (a framework for verifying Python code examples in docstrings)
186 is now part of the std library.
187
Tim Petersd66595f2001-02-04 03:09:53 +0000188Windows changes
189
Guido van Rossume3955a82001-03-02 14:05:59 +0000190- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
191 small GUI that lets you browse the module docstrings using your
192 default web browser.
193
Tim Peters1eff7962001-03-01 02:31:33 +0000194- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
195 Platforms) is implemented. See
196
197 http://python.sourceforge.net/peps/pep-0235.html
198
199 for full details, especially the "Current Lower-Left Semantics" section.
200 The new Windows import rules are simpler than before:
201
202 A. If the PYTHONCASEOK environment variable exists, same as
203 before: silently accept the first case-insensitive match of any
204 kind; raise ImportError if none found.
205
206 B. Else search sys.path for the first case-sensitive match; raise
207 ImportError if none found.
208
209 The same rules have been implented on other platforms with case-
210 insensitive but case-preserving filesystems too (including Cygwin, and
211 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +0000212
Tim Peters25a9ce32001-02-19 07:06:36 +0000213- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
214 what it's supposed to do (and does do under NT and 2000) via direct
215 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +0000216 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +0000217 all Win9x systems before.
218
Tim Peters1eff7962001-03-01 02:31:33 +0000219- Build: Subproject _test (effectively) renamed to _testcapi.
220
Tim Peters2fe289a2001-03-01 22:19:38 +0000221New platforms
222
223- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
224 Thanks to Steven Majewski!
225
226- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
227 Tishler!
228
Guido van Rossum9089b272001-03-02 06:49:50 +0000229- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
230 Schwertberger! See RISCOS/README for more information -- it seems
231 that because of the bizarre filename conventions on RISCOS, no port
232 to that platform is easy. Note that the new variable os.endsep is
233 silently supported in order to make life easier on this platform,
234 but we don't advertise it because it's not worth for most folks to
235 care about RISCOS portability.
236
Tim Peters25a9ce32001-02-19 07:06:36 +0000237
Tim Petersd7b5e882001-01-25 03:36:26 +0000238What's New in Python 2.1 alpha 2?
239=================================
Tim Peters40ead762001-01-27 05:35:26 +0000240
Tim Petersd7b5e882001-01-25 03:36:26 +0000241Core language, builtins, and interpreter
242
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000243- Scopes nest. If a name is used in a function or class, but is not
244 local, the definition in the nearest enclosing function scope will
245 be used. One consequence of this change is that lambda statements
246 could reference variables in the namespaces where the lambda is
247 defined. In some unusual cases, this change will break code.
248
249 In all previous version of Python, names were resolved in exactly
250 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000251 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000252 function A is defined within a function B, the names bound in B are
253 not visible in A. The new rules make names bound in B visible in A,
254 unless A contains a name binding that hides the binding in B.
255
256 Section 4.1 of the reference manual describes the new scoping rules
257 in detail. The test script in Lib/test/test_scope.py demonstrates
258 some of the effects of the change.
259
260 The new rules will cause existing code to break if it defines nested
261 functions where an outer function has local variables with the same
262 name as globals or builtins used by the inner function. Example:
263
264 def munge(str):
265 def helper(x):
266 return str(x)
267 if type(str) != type(''):
268 str = helper(str)
269 return str.strip()
270
271 Under the old rules, the name str in helper() is bound to the
272 builtin function str(). Under the new rules, it will be bound to
273 the argument named str and an error will occur when helper() is
274 called.
275
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000276- The compiler will report a SyntaxError if "from ... import *" occurs
277 in a function or class scope. The language reference has documented
278 that this case is illegal, but the compiler never checked for it.
279 The recent introduction of nested scope makes the meaning of this
280 form of name binding ambiguous. In a future release, the compiler
281 may allow this form when there is no possibility of ambiguity.
282
Tim Peters40ead762001-01-27 05:35:26 +0000283- repr(string) is easier to read, now using hex escapes instead of octal,
284 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
285
286 >>> "\texample \r\n" + chr(0) + chr(255)
287 '\texample \r\n\x00\xff' # in 2.1
288 '\011example \015\012\000\377' # in 2.0
289
Moshe Zadka6af0ce02001-01-29 06:41:00 +0000290- Functions are now compared and hashed by identity, not by value, since
291 the func_code attribute is writable.
292
Fred Drakefb9d7122001-02-01 20:00:40 +0000293- Weak references (PEP 205) have been added. This involves a few
294 changes in the core, an extension module (_weakref), and a Python
295 module (weakref). The weakref module is the public interface. It
296 includes support for "explicit" weak references, proxy objects, and
297 mappings with weakly held values.
298
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000299- A 'continue' statement can now appear in a try block within the body
300 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +0000301 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000302
Tim Petersd7b5e882001-01-25 03:36:26 +0000303Standard library
304
Barry Warsaw30dbd142001-01-31 22:14:01 +0000305- mailbox.py now has a new class, PortableUnixMailbox which is
306 identical to UnixMailbox but uses a more portable scheme for
307 determining From_ separators. Also, the constructors for all the
308 classes in this module have a new optional `factory' argument, which
309 is a callable used when new message classes must be instantiated by
310 the next() method.
311
Tim Petersd7b5e882001-01-25 03:36:26 +0000312- random.py is now self-contained, and offers all the functionality of
313 the now-deprecated whrandom.py. See the docs for details. random.py
314 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +0000315 and restoring the internal state of the generator; and jumpahead(n),
316 for quickly forcing the internal state to be the same as if n calls to
317 random() had been made. The latter is particularly useful for multi-
318 threaded programs, creating one instance of the random.Random() class for
319 each thread, then using .jumpahead() to force each instance to use a
320 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +0000321
Tim Peters0de88fc2001-02-01 04:59:18 +0000322- random.py's seed() function is new. For bit-for-bit compatibility with
323 prior releases, use the whseed function instead. The new seed function
324 addresses two problems: (1) The old function couldn't produce more than
325 about 2**24 distinct internal states; the new one about 2**45 (the best
326 that can be done in the Wichmann-Hill generator). (2) The old function
327 sometimes produced identical internal states when passed distinct
328 integers, and there was no simple way to predict when that would happen;
329 the new one guarantees to produce distinct internal states for all
330 arguments in [0, 27814431486576L).
331
Jeremy Hylton4c4fda02001-02-02 03:29:24 +0000332- The socket module now supports raw packets on Linux. The socket
333 family is AF_PACKET.
334
Tim Peters9ea17ac2001-02-02 05:57:15 +0000335- test_capi.py is a start at running tests of the Python C API. The tests
336 are implemented by the new Modules/_testmodule.c.
337
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000338- A new extension module, _symtable, provides provisional access to the
339 internal symbol table used by the Python compiler. A higher-level
340 interface will be added on top of _symtable in a future release.
341
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +0000342- Removed the obsolete soundex module.
343
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000344- xml.dom.minidom now uses the standard DOM exceptions. Node supports
345 the isSameNode method; NamedNodeMap the get method.
346
347- xml.sax.expatreader supports the lexical handler property; it
348 generates comment, startCDATA, and endCDATA events.
349
Tim Petersee826f82001-01-31 19:39:44 +0000350Windows changes
351
352- Build procedure: the zlib project is built in a different way that
353 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +0000354 the zlib binary used. See PCbuild\readme.txt for details. Your old
355 zlib-related directories can be deleted; you'll need to download fresh
356 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +0000357
Tim Peters9ea17ac2001-02-02 05:57:15 +0000358- Build: New subproject _test for the benefit of test_capi.py (see above).
359
Tim Petersb16c56f2001-02-02 21:24:51 +0000360- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
361 interface to some Python compiler internals).
362
363- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +0000364 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +0000365
Tim Petersa3a3a032000-11-30 05:22:44 +0000366What's New in Python 2.1 alpha 1?
367=================================
368
369Core language, builtins, and interpreter
370
Marc-André Lemburgebb195b2001-01-20 10:34:52 +0000371- There is a new Unicode companion to the PyObject_Str() API
372 called PyObject_Unicode(). It behaves in the same way as the
373 former, but assures that the returned value is an Unicode object
374 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +0000375
Guido van Rossumf98eda02001-01-17 15:54:45 +0000376- The comparison operators support "rich comparison overloading" (PEP
377 207). C extension types can provide a rich comparison function in
378 the new tp_richcompare slot in the type object. The cmp() function
379 and the C function PyObject_Compare() first try the new rich
380 comparison operators before trying the old 3-way comparison. There
381 is also a new C API PyObject_RichCompare() (which also falls back on
382 the old 3-way comparison, but does not constrain the outcome of the
383 rich comparison to a Boolean result).
384
385 The rich comparison function takes two objects (at least one of
386 which is guaranteed to have the type that provided the function) and
387 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
388 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
389 object, which may be NotImplemented (in which case the tp_compare
390 slot function is used as a fallback, if defined).
391
392 Classes can overload individual comparison operators by defining one
393 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +0000394 __ge__. There are no explicit "reflected argument" versions of
395 these; instead, __lt__ and __gt__ are each other's reflection,
396 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
397 reflection (similar at the C level). No other implications are
398 made; in particular, Python does not assume that == is the Boolean
399 inverse of !=, or that < is the Boolean inverse of >=. This makes
400 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +0000401
402 Classes or types that want to implement (in)equality tests but not
403 the ordering operators (i.e. unordered types) should implement ==
404 and !=, and raise an error for the ordering operators.
405
Guido van Rossuma88479f2001-01-18 14:28:08 +0000406 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +0000407 Boolean; e.g. a matrix type might want to return a matrix of bits
408 for A < B, giving elementwise comparisons. Such types should ensure
409 that any interpretation of their value in a Boolean context raises
410 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
411 at the C level) to always raise an exception.
412
Guido van Rossuma88479f2001-01-18 14:28:08 +0000413- Complex numbers use rich comparisons to define == and != but raise
414 an exception for <, <=, > and >=. Unfortunately, this also means
415 that cmp() of two complex numbers raises an exception when the two
416 numbers differ. Since it is not mathematically meaningful to compare
417 complex numbers except for equality, I hope that this doesn't break
418 too much code.
419
Tim Peters3389f192001-02-18 08:48:49 +0000420- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +0000421 not defined by the language, other than that it's arbitrary but
422 consistent (see the Reference Manual). An implementation detail changed
423 in 2.1a1 such that None now compares less than any other object. Code
424 relying on this new behavior (like code that relied on the previous
425 behavior) does so at its own risk.
426
Barry Warsaw573b5412001-01-15 20:43:18 +0000427- Functions and methods now support getting and setting arbitrarily
428 named attributes (PEP 232). Functions have a new __dict__
429 (a.k.a. func_dict) which hold the function attributes. Methods get
430 and set attributes on their underlying im_func. It is a TypeError
431 to set an attribute on a bound method.
432
Guido van Rossum051e3352001-01-15 19:11:10 +0000433- The xrange() object implementation has been improved so that
434 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
435 limitation that in this case len(xrange(sys.maxint)) can't be
436 calculated, but the common idiom "for i in xrange(sys.maxint)" will
437 work fine as long as the index i doesn't actually reach 2**31.
438 (Python uses regular ints for sequence and string indices; fixing
439 that is much more work.)
440
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000441- Two changes to from...import:
442
Guido van Rossumba381232001-02-03 15:06:40 +0000443 1) "from M import X" now works even if (after loading module M)
444 sys.modules['M'] is not a real module; it's basically a getattr()
445 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000446
447 2) "from M import *" now looks for M.__all__ to decide which names to
448 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
449 filters out names starting with '_' as before. Whether or not
450 __all__ exists, there's no restriction on the type of M.
451
Guido van Rossumf61f1662001-01-10 20:13:55 +0000452- File objects have a new method, xreadlines(). This is the fastest
453 way to iterate over all lines in a file:
454
455 for line in file.xreadlines():
456 ...do something to line...
457
458 See the xreadlines module (mentioned below) for how to do this for
459 other file-like objects.
460
461- Even if you don't use file.xreadlines(), you may expect a speedup on
462 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +0000463 quite a bit in platform-specific ways: on systems (like Linux) that
464 support flockfile(), getc_unlocked(), and funlockfile(), those are
465 used by default. On systems (like Windows) without getc_unlocked(),
466 a complicated (but still thread-safe) method using fgets() is used by
467 default.
468
Tim Petersd52269b2001-01-25 06:23:18 +0000469 You can force use of the fgets() method by #define'ing
470 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +0000471 getc_unlocked()).
472
Tim Petersd52269b2001-01-25 06:23:18 +0000473 You can force fgets() not to be used by #define'ing
474 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +0000475 test_bufio.py fails -- and let us know if it does!).
476
477- In addition, the fileinput module, while still slower than the other
478 methods on most platforms, has been sped up too, by using
479 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +0000480
481- Support for run-time warnings has been added, including a new
482 command line option (-W) to specify the disposition of warnings.
483 See the description of the warnings module below.
484
485- Extensive changes have been made to the coercion code. This mostly
486 affects extension modules (which can now implement mixed-type
487 numerical operators without having to use coercion), but
488 occasionally, in boundary cases the coercion semantics have changed
489 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +0000490 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +0000491 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +0000492 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +0000493
Guido van Rossumf98eda02001-01-17 15:54:45 +0000494- In connection with the coercion changes, a new built-in singleton
495 object, NotImplemented is defined. This can be returned for
496 operations that wish to indicate they are not implemented for a
497 particular combination of arguments. From C, this is
498 Py_NotImplemented.
499
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +0000500- The interpreter accepts now bytecode files on the command line even
501 if they do not have a .pyc or .pyo extension. On Linux, after executing
502
Martin v. Löwise214baa2001-02-04 22:37:56 +0000503import imp,sys,string
504magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
505reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
506open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +0000507
508 any byte code file can be used as an executable (i.e. as an argument
509 to execve(2)).
510
Tim Peters9940b802000-12-01 07:59:35 +0000511- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +0000512 character. In 1.6 and earlier, they never produced a sign,
513 and raised an error if the value of the long was too large
514 to fit in a Python int. In 2.0, they produced a sign if and
515 only if too large to fit in an int. This was inconsistent
516 across platforms (because the size of an int varies across
517 platforms), and inconsistent with hex() and oct(). Example:
518
519 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +0000520 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +0000521 'ffffffbe' # in 2.0 and before, on 32-bit machines
522 >>> hex(-0x42L)
523 '-0x42L' # in all versions of Python
524
Tim Peters9940b802000-12-01 07:59:35 +0000525 The behavior of %d formats for negative Python longs remains
526 the same as in 2.0 (although in 1.6 and before, they raised
527 an error if the long didn't fit in a Python int).
528
529 %u formats don't make sense for Python longs, but are allowed
530 and treated the same as %d in 2.1. In 2.0, a negative long
531 formatted via %u produced a sign if and only if too large to
532 fit in an int. In 1.6 and earlier, a negative long formatted
533 via %u raised an error if it was too big to fit in an int.
534
Guido van Rossum3661d392000-12-12 22:10:31 +0000535- Dictionary objects have an odd new method, popitem(). This removes
536 an arbitrary item from the dictionary and returns it (in the form of
537 a (key, value) pair). This can be useful for algorithms that use a
538 dictionary as a bag of "to do" items and repeatedly need to pick one
539 item. Such algorithms normally end up running in quadratic time;
540 using popitem() they can usually be made to run in linear time.
541
Tim Peters36cdad12000-12-29 02:06:45 +0000542Standard library
543
Thomas Woutersfe385252001-01-19 23:16:56 +0000544- In the time module, the time argument to the functions strftime,
545 localtime, gmtime, asctime and ctime is now optional, defaulting to
546 the current time (in the local timezone).
547
Guido van Rossumda91f222001-01-15 16:36:08 +0000548- The ftplib module now defaults to passive mode, which is deemed a
549 more useful default given that clients are often inside firewalls
550 these days. Note that this could break if ftplib is used to connect
551 to a *server* that is inside a firewall, from outside; this is
552 expected to be a very rare situation. To fix that, you can call
553 ftp.set_pasv(0).
554
Martin v. Löwis10a27872001-01-13 09:54:41 +0000555- The module site now treats .pth files not only for path configuration,
556 but also supports extensions to the initialization code: Lines starting
557 with import are executed.
558
Guido van Rossumf61f1662001-01-10 20:13:55 +0000559- There's a new module, warnings, which implements a mechanism for
560 issuing and filtering warnings. There are some new built-in
561 exceptions that serve as warning categories, and a new command line
562 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
563 turns warnings into errors). warnings.warn(message[, category])
564 issues a warning message; this can also be called from C as
565 PyErr_Warn(category, message).
566
567- A new module xreadlines was added. This exports a single factory
568 function, xreadlines(). The intention is that this code is the
569 absolutely fastest way to iterate over all lines in an open
570 file(-like) object:
571
572 import xreadlines
573 for line in xreadlines.xreadlines(file):
574 ...do something to line...
575
576 This is equivalent to the previous the speed record holder using
577 file.readlines(sizehint). Note that if file is a real file object
578 (as opposed to a file-like object), this is equivalent:
579
580 for line in file.xreadlines():
581 ...do something to line...
582
Tim Peters36cdad12000-12-29 02:06:45 +0000583- The bisect module has new functions bisect_left, insort_left,
584 bisect_right and insort_right. The old names bisect and insort
585 are now aliases for bisect_right and insort_right. XXX_right
586 and XXX_left methods differ in what happens when the new element
587 compares equal to one or more elements already in the list: the
588 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +0000589 right. Code that doesn't care where equal elements end up should
590 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +0000591
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +0000592- The new curses.panel module wraps the panel library that forms part
593 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
594
Guido van Rossumf61f1662001-01-10 20:13:55 +0000595- The SocketServer module now sets the allow_reuse_address flag by
596 default in the TCPServer class.
597
598- A new function, sys._getframe(), returns the stack frame pointer of
599 the caller. This is intended only as a building block for
600 higher-level mechanisms such as string interpolation.
601
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000602- The pyexpat module supports a number of new handlers, which are
603 available only in expat 1.2. If invocation of a callback fails, it
604 will report an additional frame in the traceback. Parser objects
605 participate now in garbage collection. If expat reports an unknown
606 encoding, pyexpat will try to use a Python codec; that works only
607 for single-byte charsets. The parser type objects is exposed as
608 XMLParserObject.
609
610- xml.dom now offers standard definitions for symbolic node type and
611 exception code constants, and a hierarchy of DOM exceptions. minidom
612 was adjusted to use them.
613
614- The conformance of xml.dom.minidom to the DOM specification was
615 improved. It detects a number of additional error cases; the
616 previous/next relationship works even when the tree is modified;
617 Node supports the normalize() method; NamedNodeMap, DocumentType and
618 DOMImplementation classes were added; Element supports the
619 hasAttribute and hasAttributeNS methods; and Text supports the splitText
620 method.
621
Guido van Rossumf61f1662001-01-10 20:13:55 +0000622Build issues
623
Guido van Rossum1e33bdc2001-01-23 03:17:00 +0000624- For Unix (and Unix-compatible) builds, configuration and building of
625 extension modules is now greatly automated. Rather than having to
626 edit the Modules/Setup file to indicate which modules should be
627 built and where their include files and libraries are, a
628 distutils-based setup.py script now takes care of building most
629 extension modules. All extension modules built this way are built
630 as shared libraries. Only a few modules that must be linked
631 statically are still listed in the Setup file; you won't need to
632 edit their configuration.
633
634- Python should now build out of the box on Cygwin. If it doesn't,
635 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +0000636
637- Python now always uses its own (renamed) implementation of getopt()
638 -- there's too much variation among C library getopt()
639 implementations.
640
641- C++ compilers are better supported; the CXX macro is always set to a
642 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +0000643
Tim Petersd92dfe02000-12-12 01:18:41 +0000644Windows changes
645
646- select module: By default under Windows, a select() call
647 can specify no more than 64 sockets. Python now boosts
648 this Microsoft default to 512. If you need even more than
649 that, see the MS docs (you'll need to #define FD_SETSIZE
650 and recompile Python from source).
651
Guido van Rossumf61f1662001-01-10 20:13:55 +0000652- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
653 subdirectory is no more!
654
Tim Petersa3a3a032000-11-30 05:22:44 +0000655
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000656What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +0000657=========================
Guido van Rossum61000331997-08-15 04:39:58 +0000658
Guido van Rossum8ed602b2000-09-01 22:34:33 +0000659Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000660changes are in the file HISTORY. If you are making the jump directly
661from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
662HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +0000663
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000664Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
665the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
666http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +0000667
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000668--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +0000669
670======================================================================
671
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000672What's new in 2.0 (since release candidate 1)?
673==============================================
674
675Standard library
676
677- The copy_reg module was modified to clarify its intended use: to
678 register pickle support for extension types, not for classes.
679 pickle() will raise a TypeError if it is passed a class.
680
681- Fixed a bug in gettext's "normalize and expand" code that prevented
682 it from finding an existing .mo file.
683
684- Restored support for HTTP/0.9 servers in httplib.
685
Tim Peters989b7b92000-10-16 20:24:53 +0000686- The math module was changed to stop raising OverflowError in case of
687 underflow, and return 0 instead in underflow cases. Whether Python
688 used to raise OverflowError in case of underflow was platform-
689 dependent (it did when the platform math library set errno to ERANGE
690 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000691
692- Fixed a bug in StringIO that occurred when the file position was not
693 at the end of the file and write() was called with enough data to
694 extend past the end of the file.
695
696- Fixed a bug that caused Tkinter error messages to get lost on
697 Windows. The bug was fixed by replacing direct use of
698 interp->result with Tcl_GetStringResult(interp).
699
700- Fixed bug in urllib2 that caused it to fail when it received an HTTP
701 redirect response.
702
703- Several changes were made to distutils: Some debugging code was
704 removed from util. Fixed the installer used when an external zip
705 program (like WinZip) is not found; the source code for this
706 installer is in Misc/distutils. check_lib() was modified to behave
707 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
708 test for whether installed modules are on sys.path was changed to
709 use both normcase() and normpath().
710
Jeremy Hyltond867a2c2000-10-16 20:41:38 +0000711- Several minor bugs were fixed in the xml package (the minidom,
712 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000713
714- The regression test driver (regrtest.py) behavior when invoked with
715 -l changed: It now reports a count of objects that are recognized as
716 garbage but not freed by the garbage collector.
717
Tim Peters989b7b92000-10-16 20:24:53 +0000718- The regression test for the math module was changed to test
719 exceptional behavior when the test is run in verbose mode. Python
720 cannot yet guarantee consistent exception behavior across platforms,
721 so the exception part of test_math is run only in verbose mode, and
722 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000723
724Internals
725
726- PyOS_CheckStack() has been disabled on Win64, where it caused
727 test_sre to fail.
728
729Build issues
730
731- Changed compiler flags, so that gcc is always invoked with -Wall and
732 -Wstrict-prototypes. Users compiling Python with GCC should see
733 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +0000734 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +0000735 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000736
Tim Petersa3a3a032000-11-30 05:22:44 +0000737- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000738
739Tools and other miscellany
740
741- The compiler in Tools/compiler was updated to support the new
742 language features introduced in 2.0: extended print statement, list
743 comprehensions, and augmented assignments. The new compiler should
744 also be backwards compatible with Python 1.5.2; the compiler will
745 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +0000746 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000747
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000748What's new in 2.0 release candidate 1 (since beta 2)?
749=====================================================
750
Jeremy Hylton6040aaa2000-10-09 21:27:22 +0000751What is release candidate 1?
752
753We believe that release candidate 1 will fix all known bugs that we
754intend to fix for the 2.0 final release. This release should be a bit
755more stable than the previous betas. We would like to see even more
756widespread testing before the final release, so we are producing this
757release candidate. The final release will be exactly the same unless
758any show-stopping (or brown bag) bugs are found by testers of the
759release candidate.
760
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000761All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000762to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000763
764Core language, builtins, and interpreter
765
766- A bug that caused crashes when __coerce__ was used with augmented
767 assignment, e.g. +=, was fixed.
768
769- Raise ZeroDivisionError when raising zero to a negative number,
770 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
771 power operator and the result of math.pow(0.0, -2.0) will vary by
772 platform. On Linux, it raises a ValueError.
773
774- A bug in Unicode string interpolation was fixed that occasionally
775 caused errors with formats including "%%". For example, the
776 following expression "%% %s" % u"abc" no longer raises a TypeError.
777
778- Compilation of deeply nested expressions raises MemoryError instead
779 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
780
781- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
782 rendering them useless. They are now written in binary mode again.
783
784Standard library
785
786- Keyword arguments are now accepted for most pattern and match object
787 methods in SRE, the standard regular expression engine.
788
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000789- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +0000790 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000791
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000792- Several bugs in the Unicode handling and error handling in _tkinter
793 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000794
795- Fix memory management errors in Merge() and Tkapp_Call() routines.
796
797- Several changes were made to cStringIO to make it compatible with
798 the file-like object interface and with StringIO. If operations are
799 performed on a closed object, an exception is raised. The truncate
800 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +0000801 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000802
803- There were many changes made to the linuxaudiodev module and its
804 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +0000805 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000806
807 Note that this module is named poorly, because it should work
808 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +0000809 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000810
811 The module now raises exceptions when errors occur instead of
812 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
813 audio) and defines a getptr() method that calls the
814 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
815
816- The library_version attribute, introduced in an earlier beta, was
817 removed because it can not be supported with early versions of the C
818 readline library, which provides no way to determine the version at
819 compile-time.
820
821- The binascii module is now enabled on Win64.
822
Tim Peters46446d62000-10-09 21:19:31 +0000823- tokenize.py no longer suffers "recursion depth" errors when parsing
824 programs with very long string literals.
825
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000826Internals
827
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000828- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000829 which is called when the interpreter starts up to determine where
830 the standard library is installed. These vulnerabilities affect all
831 previous versions of Python and can be exploited by setting very
832 long values for PYTHONHOME or argv[0]. The risk is greatest for a
833 setuid Python script, although use of the wrapper in
834 Misc/setuid-prog.c will eliminate the vulnerability.
835
836- Fixed garbage collection bugs in instance creation that were
837 triggered when errors occurred during initialization. The solution,
838 applied in cPickle and in PyInstance_New(), is to call
839 PyObject_GC_Init() after the initialization of the object's
840 container attributes is complete.
841
842- pyexpat adds definitions of PyModule_AddStringConstant and
843 PyModule_AddObject if the Python version is less than 2.0, which
844 provides compatibility with PyXML on Python 1.5.2.
845
846- If the platform has a bogus definition for LONG_BIT (the number of
847 bits in a long), an error will be reported at compile time.
848
849- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
850 collection crashes and possibly other, unreported crashes.
851
852- Fixed a memory leak in _PyUnicode_Fini().
853
854Build issues
855
856- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000857 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +0000858 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000859
860- The mmap.PAGESIZE constant is now initialized using sysconf when
861 possible, which eliminates a dependency on -lucb for Reliant UNIX.
862
863- The md5 file should now compile on all platforms.
864
865- The select module now compiles on platforms that do not define
866 POLLRDNORM and related constants.
867
868- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +0000869 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000870
Jeremy Hylton10921202000-10-09 18:34:12 +0000871- BeOS: A number of changes were made to the build and installation
872 process. ar-fake now operates on a directory of object files.
873 dl_export.h is gone, and its macros now appear on the mwcc command
874 line during build on PPC BeOS.
875
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000876- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +0000877 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000878
879- Cygwin: Support for shared libraries, Tkinter, and sockets.
880
881- SunOS 4.1.4_JL: Fix test for directory existence in configure.
882
883Tools and other miscellany
884
885- Removed debugging prints from main used with freeze.
886
Tim Peters46446d62000-10-09 21:19:31 +0000887- IDLE auto-indent no longer crashes when it encounters Unicode
888 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000889
890What's new in 2.0 beta 2 (since beta 1)?
891========================================
892
893Core language, builtins, and interpreter
894
Tim Peters482c0212000-09-26 06:33:09 +0000895- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000896 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +0000897
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000898- Add -h and -V command line options to print the usage message and
899 Python version number and exit immediately.
900
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +0000901- eval() and exec accept Unicode objects as code parameters.
902
903- getattr() and setattr() now also accept Unicode objects for the
904 attribute name, which are converted to strings using the default
905 encoding before lookup.
906
907- Multiplication on string and Unicode now does proper bounds
908 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
909 string is too long."
910
911- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +0000912 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +0000913
Jeremy Hylton1b618592000-09-26 05:32:36 +0000914
915Standard library and extensions
916
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000917- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +0000918 argument checking; it still takes no arguments.
919
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000920- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000921
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000922- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000923
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000924- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +0000925
926- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000927 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000928
929- copy: Copy Unicode objects atomically.
930
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000931- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000932
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000933- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000934
Fred Drake67233bc2000-09-26 16:40:27 +0000935- dbm: Add get() and setdefault() methods to dbm object. Add constant
936 `library' to module that names the library used. Added doc strings
937 and method names to error messages. Uses configure to determine
938 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
939 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000940
941- distutils: Update to version 0.9.3.
942
943- dl: Add several dl.RTLD_ constants.
944
945- fpectl: Now supported on FreeBSD.
946
947- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
948 found by the collector will be saved in gc.garbage. This is useful
949 for debugging a program that creates reference cycles.
950
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000951- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +0000952 of HTTP class. Do not close socket on zero-length response. Do not
953 crash when server sends invalid content-length header.
954
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000955- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000956
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +0000957- marshal: When reading a short, sign-extend on platforms where shorts
958 are bigger than 16 bits. When reading a long, repair the unportable
959 sign extension that was being done for 64-bit machines. (It assumed
960 that signed right shift sign-extends.)
961
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000962- operator: Add contains(), invert(), __invert__() as aliases for
963 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000964
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000965- os: Add support for popen2() and popen3() on all platforms where
966 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +0000967
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000968- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +0000969 clicking on a file in Explorer (or passing the file name to the
970 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +0000971
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000972- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +0000973 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +0000974
975- pickle: Now raises ValueError when an invalid pickle that contains
976 a non-string repr where a string repr was expected. This behavior
977 matches cPickle.
978
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000979- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000980
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000981- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000982
983- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +0000984 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000985 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +0000986
987- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000988 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000989
990- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +0000991 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +0000992 few cycles during startup since the first call to
993 setdefaultencoding() will initialize the codec registry and the
994 encodings package.
995
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000996- socket: Support for size hint in readlines() method of object returned
997 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +0000998
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000999- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001000 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001001 is followed by whitespace.
1002
Tim Petersa3a3a032000-11-30 05:22:44 +00001003- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001004
1005- struct: Check ranges for bytes and shorts.
1006
1007- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001008 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001009
1010- Tkinter: Image objects are now guaranteed to have unique ids. Set
1011 event.delta to zero if Tk version doesn't support mousewheel.
1012 Removed some debugging prints.
1013
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001014- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001015
Fred Drake67233bc2000-09-26 16:40:27 +00001016- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001017 which works around a bug in Norton AntiVirus 2000 that leads directly
1018 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001019
1020- xml: New version detection code allows PyXML to override standard
1021 XML package if PyXML version is greater than 0.6.1.
1022
Fred Drake64bb3802000-09-26 16:21:35 +00001023- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
1024 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
1025 tree only for nodes which are sufficiently interesting to a specific
1026 application. Does not provide the HTML-specific extensions. Still
1027 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001028
Fred Drake64bb3802000-09-26 16:21:35 +00001029- xml.sax: SAX 2 support for Python, including all the handler
1030 interfaces needed to process XML 1.0 compliant XML. Some
1031 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001032
Fred Drake64bb3802000-09-26 16:21:35 +00001033- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
1034 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001035
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001036
Jeremy Hylton1b618592000-09-26 05:32:36 +00001037C API
1038
1039- Add three new convenience functions for module initialization --
1040 PyModule_AddObject(), PyModule_AddIntConstant(), and
1041 PyModule_AddStringConstant().
1042
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001043- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00001044 removed and add #error to Python.h if NULL isn't defined after
1045 #include of stdio.h.
1046
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001047- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00001048 backwards compatibility (at the source level) with old extensions.
1049
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001050- A wrapper API was added for signal() and sigaction(). Instead of
1051 either function, always use PyOS_getsig() to get a signal handler
1052 and PyOS_setsig() to set one. A new convenience typedef
1053 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001054
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001055- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00001056 internal data buffer and size of a string object -- or the default
1057 encoded version of a Unicode object.
1058
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001059- PyString_Size() and PyString_AsString() accept Unicode objects.
1060
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001061- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00001062 exists). INT_MAX and LONG_MAX will always be defined, even if
1063 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001064
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001065- PyFloat_FromString takes a second argument, pend, that was
1066 effectively useless. It is now officially useless but preserved for
1067 backwards compatibility. If the pend argument is not NULL, *pend is
1068 set to NULL.
1069
1070- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
1071 for the attribute name. See note on getattr() above.
1072
1073- A few bug fixes to argument processing for Unicode.
1074 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
1075 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
1076 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00001077 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001078
1079- Py_BuildValue accepts B format (for bgen-generated code).
1080
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001081
Jeremy Hylton1b618592000-09-26 05:32:36 +00001082Internals
1083
1084- On Unix, fix code for finding Python installation directory so that
1085 it works when argv[0] is a relative path.
1086
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00001087- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001088 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00001089 rather than by generating a copy of the object.
1090
Tim Peters482c0212000-09-26 06:33:09 +00001091- Several of the internal Unicode tables are much smaller now, and
1092 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001093
Jeremy Hylton97693b02000-09-26 17:42:51 +00001094- In the garbage collector: Fixed bug in collection of tuples. Fixed
1095 bug that caused some instances to be removed from the container set
1096 while they were still live. Fixed parsing in gc.set_debug() for
1097 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001098
1099- Fixed refcount problem in instance deallocation that only occurred
1100 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
1101
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001102- On Windows, getpythonregpath is now protected against null data in
1103 registry key.
1104
1105- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00001106 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001107
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001108
Jeremy Hylton1b618592000-09-26 05:32:36 +00001109Build and platform-specific issues
1110
1111- Better support of GNU Pth via --with-pth configure option.
1112
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001113- Python/C API now properly exposed to dynamically-loaded extension
1114 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001115
1116- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
1117 Don't define MS_SYNC to be zero when it is undefined. Added missing
1118 prototypes in posixmodule.c.
1119
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001120- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001121 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001122
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001123- Fix largefile support on older NetBSD systems and OpenBSD by adding
1124 define for TELL64.
1125
1126
1127Tools and other miscellany
1128
1129- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
1130
1131- freeze: The modulefinder now works with 2.0 opcodes.
1132
Tim Petersa3a3a032000-11-30 05:22:44 +00001133- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001134 Move hackery of sys.argv until after the Tk instance has been
1135 created, which allows the application-specific Tkinter
1136 initialization to be executed if present; also pass an explicit
1137 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00001138
Jeremy Hylton1b618592000-09-26 05:32:36 +00001139
1140What's new in 2.0 beta 1?
1141=========================
1142
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001143Source Incompatibilities
1144------------------------
1145
1146None. Note that 1.6 introduced several incompatibilities with 1.5.2,
1147such as single-argument append(), connect() and bind(), and changes to
1148str(long) and repr(float).
1149
1150
1151Binary Incompatibilities
1152------------------------
1153
1154- Third party extensions built for Python 1.5.x or 1.6 cannot be used
1155with Python 2.0; these extensions will have to be rebuilt for Python
11562.0.
1157
1158- On Windows, attempting to import a third party extension built for
1159Python 1.5.x or 1.6 results in an immediate crash; there's not much we
1160can do about this. Check your PYTHONPATH environment variable!
1161
1162- Python bytecode files (*.pyc and *.pyo) are not compatible between
1163releases.
1164
1165
1166Overview of Changes Since 1.6
1167-----------------------------
1168
1169There are many new modules (including brand new XML support through
1170the xml package, and i18n support through the gettext module); a list
1171of all new modules is included below. Lots of bugs have been fixed.
1172
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001173The process for making major new changes to the language has changed
1174since Python 1.6. Enhancements must now be documented by a Python
1175Enhancement Proposal (PEP) before they can be accepted.
1176
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001177There are several important syntax enhancements, described in more
1178detail below:
1179
1180 - Augmented assignment, e.g. x += 1
1181
1182 - List comprehensions, e.g. [x**2 for x in range(10)]
1183
1184 - Extended import statement, e.g. import Module as Name
1185
1186 - Extended print statement, e.g. print >> file, "Hello"
1187
1188Other important changes:
1189
1190 - Optional collection of cyclical garbage
1191
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001192Python Enhancement Proposal (PEP)
1193---------------------------------
1194
1195PEP stands for Python Enhancement Proposal. A PEP is a design
1196document providing information to the Python community, or describing
1197a new feature for Python. The PEP should provide a concise technical
1198specification of the feature and a rationale for the feature.
1199
1200We intend PEPs to be the primary mechanisms for proposing new
1201features, for collecting community input on an issue, and for
1202documenting the design decisions that have gone into Python. The PEP
1203author is responsible for building consensus within the community and
1204documenting dissenting opinions.
1205
1206The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001207
1208Augmented Assignment
1209--------------------
1210
1211This must have been the most-requested feature of the past years!
1212Eleven new assignment operators were added:
1213
Guido van Rossume905e952000-09-05 12:42:46 +00001214 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001215
1216For example,
1217
1218 A += B
1219
1220is similar to
1221
1222 A = A + B
1223
1224except that A is evaluated only once (relevant when A is something
1225like dict[index].attr).
1226
1227However, if A is a mutable object, A may be modified in place. Thus,
1228if A is a number or a string, A += B has the same effect as A = A+B
1229(except A is only evaluated once); but if a is a list, A += B has the
1230same effect as A.extend(B)!
1231
1232Classes and built-in object types can override the new operators in
1233order to implement the in-place behavior; the not-in-place behavior is
1234used automatically as a fallback when an object doesn't implement the
1235in-place behavior. For classes, the method name is derived from the
1236method name for the corresponding not-in-place operator by inserting
1237an 'i' in front of the name, e.g. __iadd__ implements in-place
1238__add__.
1239
1240Augmented assignment was implemented by Thomas Wouters.
1241
1242
1243List Comprehensions
1244-------------------
1245
1246This is a flexible new notation for lists whose elements are computed
1247from another list (or lists). The simplest form is:
1248
1249 [<expression> for <variable> in <sequence>]
1250
Guido van Rossum56db0952000-09-06 23:34:25 +00001251For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001252This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001253
1254You can also add a condition:
1255
1256 [<expression> for <variable> in <sequence> if <condition>]
1257
1258For example, [w for w in words if w == w.lower()] would yield the list
1259of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001260than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001261
1262You can also have nested for loops and more than one 'if' clause. For
1263example, here's a function that flattens a sequence of sequences::
1264
1265 def flatten(seq):
1266 return [x for subseq in seq for x in subseq]
1267
1268 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
1269
1270This prints
1271
1272 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
1273
1274List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001275Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001276
1277
1278Extended Import Statement
1279-------------------------
1280
1281Many people have asked for a way to import a module under a different
1282name. This can be accomplished like this:
1283
1284 import foo
1285 bar = foo
1286 del foo
1287
1288but this common idiom gets old quickly. A simple extension of the
1289import statement now allows this to be written as follows:
1290
1291 import foo as bar
1292
1293There's also a variant for 'from ... import':
1294
1295 from foo import bar as spam
1296
1297This also works with packages; e.g. you can write this:
1298
1299 import test.regrtest as regrtest
1300
1301Note that 'as' is not a new keyword -- it is recognized only in this
1302context (this is only possible because the syntax for the import
1303statement doesn't involve expressions).
1304
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001305Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001306
1307
1308Extended Print Statement
1309------------------------
1310
1311Easily the most controversial new feature, this extension to the print
1312statement adds an option to make the output go to a different file
1313than the default sys.stdout.
1314
1315For example, to write an error message to sys.stderr, you can now
1316write:
1317
1318 print >> sys.stderr, "Error: bad dog!"
1319
1320As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00001321evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001322
1323 print >> None, "Hello world"
1324
1325is equivalent to
1326
1327 print "Hello world"
1328
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001329Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001330
1331
1332Optional Collection of Cyclical Garbage
1333---------------------------------------
1334
1335Python is now equipped with a garbage collector that can hunt down
1336cyclical references between Python objects. It's no replacement for
1337reference counting; in fact, it depends on the reference counts being
1338correct, and decides that a set of objects belong to a cycle if all
1339their reference counts can be accounted for from their references to
1340each other. This devious scheme was first proposed by Eric Tiedemann,
1341and brought to implementation by Neil Schemenauer.
1342
1343There's a module "gc" that lets you control some parameters of the
1344garbage collection. There's also an option to the configure script
1345that lets you enable or disable the garbage collection. In 2.0b1,
1346it's on by default, so that we (hopefully) can collect decent user
1347experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00001348performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001349off by default in the final 2.0 release.
1350
1351
1352Smaller Changes
1353---------------
1354
1355A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
1356map(None, seq1, seq2, ...) when the sequences have the same length;
1357i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
1358the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001359zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001360
1361sys.version_info is a tuple (major, minor, micro, level, serial).
1362
1363Dictionaries have an odd new method, setdefault(key, default).
1364dict.setdefault(key, default) returns dict[key] if it exists; if not,
1365it sets dict[key] to default and returns that value. Thus:
1366
1367 dict.setdefault(key, []).append(item)
1368
1369does the same work as this common idiom:
1370
1371 if not dict.has_key(key):
1372 dict[key] = []
1373 dict[key].append(item)
1374
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001375There are two new variants of SyntaxError that are raised for
1376indentation-related errors: IndentationError and TabError.
1377
1378Changed \x to consume exactly two hex digits; see PEP 223. Added \U
1379escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001380
1381The limits on the size of expressions and file in Python source code
1382have been raised from 2**16 to 2**32. Previous versions of Python
1383were limited because the maximum argument size the Python VM accepted
1384was 2**16. This limited the size of object constructor expressions,
1385e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
1386limit was raised thanks to a patch by Charles Waldman that effectively
1387fixes the problem. It is now much more likely that you will be
1388limited by available memory than by an arbitrary limit in Python.
1389
1390The interpreter's maximum recursion depth can be modified by Python
1391programs using sys.getrecursionlimit and sys.setrecursionlimit. This
1392limit is the maximum number of recursive calls that can be made by
1393Python code. The limit exists to prevent infinite recursion from
1394overflowing the C stack and causing a core dump. The default value is
13951000. The maximum safe value for a particular platform can be found
1396by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001397
1398New Modules and Packages
1399------------------------
1400
1401atexit - for registering functions to be called when Python exits.
1402
1403imputil - Greg Stein's alternative API for writing custom import
1404hooks.
1405
1406pyexpat - an interface to the Expat XML parser, contributed by Paul
1407Prescod.
1408
1409xml - a new package with XML support code organized (so far) in three
1410subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
1411would fill a volume. There's a special feature whereby a
1412user-installed package named _xmlplus overrides the standard
1413xmlpackage; this is intended to give the XML SIG a hook to distribute
1414backwards-compatible updates to the standard xml package.
1415
1416webbrowser - a platform-independent API to launch a web browser.
1417
1418
Guido van Rossume905e952000-09-05 12:42:46 +00001419Changed Modules
1420---------------
1421
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001422array -- new methods for array objects: count, extend, index, pop, and
1423remove
1424
1425binascii -- new functions b2a_hex and a2b_hex that convert between
1426binary data and its hex representation
1427
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001428calendar -- Many new functions that support features including control
1429over which day of the week is the first day, returning strings instead
1430of printing them. Also new symbolic constants for days of week,
1431e.g. MONDAY, ..., SUNDAY.
1432
1433cgi -- FieldStorage objects have a getvalue method that works like a
1434dictionary's get method and returns the value attribute of the object.
1435
1436ConfigParser -- The parser object has new methods has_option,
1437remove_section, remove_option, set, and write. They allow the module
1438to be used for writing config files as well as reading them.
1439
1440ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00001441optionally support the RFC 959 REST command.
1442
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001443gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00001444
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001445httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
1446the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00001447
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001448locale -- implement getdefaultlocale for Win32 and Macintosh
1449
1450marshal -- no longer dumps core when marshaling deeply nested or
1451recursive data structures
1452
1453os -- new functions isatty, seteuid, setegid, setreuid, setregid
1454
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001455os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
1456support under Unix.
1457
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001458os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001459
1460os.path -- fix semantics of os.path.commonprefix
1461
1462smtplib -- support for sending very long messages
1463
1464socket -- new function getfqdn()
1465
1466readline -- new functions to read, write and truncate history files.
1467The readline section of the library reference manual contains an
1468example.
1469
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001470select -- add interface to poll system call
1471
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001472shutil -- new copyfileobj function
1473
1474SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
1475HTTP server.
1476
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001477Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001478
1479urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00001480e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001481
1482whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00001483
1484
1485Obsolete Modules
1486----------------
1487
1488None. However note that 1.6 made a whole slew of modules obsolete:
1489stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
1490poly, zmod, strop, util, whatsound.
1491
1492
1493Changed, New, Obsolete Tools
1494----------------------------
1495
Tim Peters8b092332000-09-05 20:15:25 +00001496None.
Guido van Rossume905e952000-09-05 12:42:46 +00001497
1498
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001499C-level Changes
1500---------------
1501
1502Several cleanup jobs were carried out throughout the source code.
1503
1504All C code was converted to ANSI C; we got rid of all uses of the
1505Py_PROTO() macro, which makes the header files a lot more readable.
1506
1507Most of the portability hacks were moved to a new header file,
1508pyport.h; several other new header files were added and some old
1509header files were removed, in an attempt to create a more rational set
1510of header files. (Few of these ever need to be included explicitly;
1511they are all included by Python.h.)
1512
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001513Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001514and Win64, especially for the new Intel Itanium processor. Mick also
1515added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001516
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001517The C APIs to return an object's size have been update to consistently
1518use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
1519previous versions, the abstract interfaces used PyXXX_Length and the
1520concrete interfaces used PyXXX_Size. The old names,
1521e.g. PyObject_Length, are still available for backwards compatibility
1522at the API level, but are deprecated.
1523
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001524The PyOS_CheckStack function has been implemented on Windows by
1525Fredrik Lundh. It prevents Python from failing with a stack overflow
1526on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001527
1528The GC changes resulted in creation of two new slots on object,
1529tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00001530the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001531
1532The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00001533C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001534
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001535PyErr_Format has been updated to automatically calculate the size of
1536the buffer needed to hold the formatted result string. This change
1537prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001538
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001539New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00001540
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001541PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
1542that are the same as their non-Ex counterparts except they take an
1543extra flag argument that tells them to close the file when done.
1544
1545XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00001546
Tim Peters8b092332000-09-05 20:15:25 +00001547
1548Windows Changes
1549---------------
1550
1551New popen2/popen3/peopen4 in os module (see Changed Modules above).
1552
1553os.popen is much more usable on Windows 95 and 98. See Microsoft
1554Knowledge Base article Q150956. The Win9x workaround described there
1555is implemented by the new w9xpopen.exe helper in the root of your
1556Python installation. Note that Python uses this internally; it is not
1557a standalone program.
1558
1559Administrator privileges are no longer required to install Python
1560on Windows NT or Windows 2000. If you have administrator privileges,
1561Python's registry info will be written under HKEY_LOCAL_MACHINE.
1562Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00001563under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00001564uses of Python, but will prevent some advanced uses from working
1565(for example, running a Python script as an NT service, or possibly
1566from CGI).
1567
1568[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
1569installer; instead, it installs the needed Tcl/Tk files directly in the
1570Python directory. If you already have a Tcl/Tk installation, this
1571wastes some disk space (about 4 Megs) but avoids problems with
1572conflicting Tcl/Tk installations, and makes it much easier for Python
1573to ensure that Tcl/Tk can find all its files.
1574
1575[This was new in 1.6] The Windows installer now installs by default in
1576\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
1577
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001578
1579Updates to the changes between 1.5.2 and 1.6
1580--------------------------------------------
1581
1582The 1.6 NEWS file can't be changed after the release is done, so here
1583is some late-breaking news:
1584
1585New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
1586and changes to getlocale() and setlocale().
1587
1588The new module is now enabled per default.
1589
1590It is not true that the encodings codecs cannot be used for normal
1591strings: the string.encode() (which is also present on 8-bit strings
1592!) allows using them for 8-bit strings too, e.g. to convert files from
1593cp1252 (Windows) to latin-1 or vice-versa.
1594
1595Japanese codecs are available from Tamito KAJIYAMA:
1596http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
1597
1598
Guido van Rossumab9d6f01998-08-10 22:01:13 +00001599======================================================================