blob: e3bb40532dffbe542d996ccd0dc366210507e99f [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
Guido van Rossum34d37dc2001-04-11 21:03:32 +000010- New port: SCO Unixware 7, by Billy G. Allie.
11
12- Updated the RISCOS port.
13
Barry Warsaw11e89c72001-04-11 20:37:57 +000014
Martin v. Löwis0411f6f2001-03-21 08:01:39 +000015What's New in Python 2.1 beta 2?
16================================
17
Guido van Rossum053ae352001-03-22 14:17:21 +000018(Unlisted are many fixed bugs, more documentation, etc.)
19
Martin v. Löwis0411f6f2001-03-21 08:01:39 +000020Core language, builtins, and interpreter
21
Guido van Rossum053ae352001-03-22 14:17:21 +000022- The nested scopes work (enabled by "from __future__ import
23 nested_scopes") is completed; in particular, the future now extends
24 into code executed through exec, eval() and execfile(), and into the
25 interactive interpreter.
26
27- When calling a base class method (e.g. BaseClass.__init__(self)),
28 this is now allowed even if self is not strictly spoken a class
29 instance (e.g. when using metaclasses or the Don Beaudry hook).
30
31- Slice objects are now comparable but not hashable; this prevents
32 dict[:] from being accepted but meaningless.
33
34- Complex division is now calculated using less braindead algorithms.
35 This doesn't change semantics except it's more likely to give useful
36 results in extreme cases. Complex repr() now uses full precision
37 like float repr().
38
39- sgmllib.py now calls handle_decl() for simple <!...> declarations.
40
Jeremy Hyltonf626db72001-03-23 14:18:27 +000041- It is illegal to assign to the name __debug__, which is set when the
42 interpreter starts. It is effectively a compile-time constant.
43
44- A warning will be issued if a global statement for a variable
45 follows a use or assignment of that variable.
46
Martin v. Löwis0411f6f2001-03-21 08:01:39 +000047Standard library
48
Guido van Rossum053ae352001-03-22 14:17:21 +000049- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
50 inspired by JUnit), is now part of the standard library. You now
51 have a choice of two testing frameworks: unittest requires you to
52 write testcases as separate code, doctest gathers them from
53 docstrings. Both approaches have their advantages and
54 disadvantages.
55
56- A new module Tix was added, which wraps the Tix extension library
57 for Tk. With that module, it is not necessary to statically link
58 Tix with _tkinter, since Tix will be loaded with Tcl's "package
59 require" command. See Demo/tix/.
60
61- tzparse.py is now obsolete.
62
63- In gzip.py, the seek() and tell() methods are removed -- they were
64 non-functional anyway, and it's better if callers can test for their
65 existence with hasattr().
66
67Python/C API
68
69- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
70 that's already in the dictionary during a PyDict_Next() iteration.
71 This used to fail occasionally when a dictionary resize operation
72 could be triggered that would rehash all the keys. All other
73 modifications to the dictionary are still off-limits during a
74 PyDict_Next() iteration!
75
76- New extended APIs related to passing compiler variables around.
77
78- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
79 implement isinstance() and issubclass().
80
81- Py_BuildValue() now has a "D" conversion to create a Python complex
82 number from a Py_complex C value.
Martin v. Löwis0411f6f2001-03-21 08:01:39 +000083
Fred Drake4e262a92001-03-22 18:26:47 +000084- Extensions types which support weak references must now set the
85 field allocated for the weak reference machinery to NULL themselves;
86 this is done to avoid the cost of checking each object for having a
87 weakly referencable type in PyObject_INIT(), since most types are
88 not weakly referencable.
89
Jeremy Hyltonf626db72001-03-23 14:18:27 +000090- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
91 free variables and cell variables to and from the frame's f_locals.
92
93- Variants of several functions defined in pythonrun.h have been added
94 to support the nested_scopes future statement. The variants all end
95 in Flags and take an extra argument, a PyCompilerFlags *; examples:
96 PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
97 variants may be removed in Python 2.2, when nested scopes are
98 mandatory.
99
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000100Distutils
101
102- the sdist command now writes a PKG-INFO file, as described in PEP 241,
103 into the release tree.
104
105- several enhancements to the bdist_wininst command from Thomas Heller
106 (an uninstaller, more customization of the installer's display)
107
108- from Jack Jansen: added Mac-specific code to generate a dialog for
109 users to specify the command-line (because providing a command-line with
110 MacPython is awkward). Jack also made various fixes for the Mac
111 and the Metrowerks compiler.
112
113- added 'platforms' and 'keywords' to the set of metadata that can be
Andrew M. Kuchling68ad64a2001-03-31 02:42:42 +0000114 specified for a distribution.
Andrew M. Kuchling8e9972c2001-03-22 15:42:08 +0000115
116- applied patches from Jason Tishler to make the compiler class work with
117 Cygwin.
118
119
Tim Peters2fe289a2001-03-01 22:19:38 +0000120What's New in Python 2.1 beta 1?
121================================
Tim Petersd66595f2001-02-04 03:09:53 +0000122
123Core language, builtins, and interpreter
124
Guido van Rossum9d0fbde2001-03-02 14:00:32 +0000125- Following an outcry from the community about the amount of code
126 broken by the nested scopes feature introduced in 2.1a2, we decided
127 to make this feature optional, and to wait until Python 2.2 (or at
128 least 6 months) to make it standard. The option can be enabled on a
129 per-module basis by adding "from __future__ import nested_scopes" at
130 the beginning of a module (before any other statements, but after
131 comments and an optional docstring). See PEP 236 (Back to the
132 __future__) for a description of the __future__ statement. PEP 227
133 (Statically Nested Scopes) has been updated to reflect this change,
134 and to clarify the semantics in a number of endcases.
135
136- The nested scopes code, when enabled, has been hardened, and most
137 bugs and memory leaks in it have been fixed.
138
139- Compile-time warnings are now generated for a number of conditions
140 that will break or change in meaning when nested scopes are enabled:
141
142 - Using "from...import *" or "exec" without in-clause in a function
143 scope that also defines a lambda or nested function with one or
144 more free (non-local) variables. The presence of the import* or
145 bare exec makes it impossible for the compiler to determine the
146 exact set of local variables in the outer scope, which makes it
147 impossible to determine the bindings for free variables in the
148 inner scope. To avoid the warning about import *, change it into
149 an import of explicitly name object, or move the import* statement
150 to the global scope; to avoid the warning about bare exec, use
151 exec...in... (a good idea anyway -- there's a possibility that
152 bare exec will be deprecated in the future).
153
154 - Use of a global variable in a nested scope with the same name as a
155 local variable in a surrounding scope. This will change in
156 meaning with nested scopes: the name in the inner scope will
157 reference the variable in the outer scope rather than the global
158 of the same name. To avoid the warning, either rename the outer
159 variable, or use a global statement in the inner function.
160
Neil Schemenauera35c6882001-02-27 04:45:05 +0000161- An optional object allocator has been included. This allocator is
162 optimized for Python objects and should be faster and use less memory
163 than the standard system allocator. It is not enabled by default
164 because of possible thread safety problems. The allocator is only
165 protected by the Python interpreter lock and it is possible that some
166 extension modules require a thread safe allocator. The object
167 allocator can be enabled by providing the "--with-pymalloc" option to
168 configure.
169
Tim Petersd66595f2001-02-04 03:09:53 +0000170Standard library
171
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000172- pyexpat now detects the expat version if expat.h defines it. A
173 number of additional handlers are provided, which are only available
174 since expat 1.95. In addition, the methods SetParamEntityParsing and
175 GetInputContext of Parser objects are available with 1.95.x
176 only. Parser objects now provide the ordered_attributes and
177 specified_attributes attributes. A new module expat.model was added,
178 which offers a number of additional constants if 1.95.x is used.
179
180- xml.dom offers the new functions registerDOMImplementation and
181 getDOMImplementation.
182
183- xml.dom.minidom offers a toprettyxml method. A number of DOM
184 conformance issues have been resolved. In particular, Element now
185 has an hasAttributes method, and the handling of namespaces was
186 improved.
187
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000188- Ka-Ping Yee contributed two new modules: inspect.py, a module for
189 getting information about live Python code, and pydoc.py, a module
190 for interactively converting docstrings to HTML or text.
191 Tools/scripts/pydoc, which is now automatically installed into
Tim Peters1eff7962001-03-01 02:31:33 +0000192 <prefix>/bin, uses pydoc.py to display documentation; try running
Guido van Rossume3955a82001-03-02 14:05:59 +0000193 "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
194 lets you browse the module docstrings using a web browser.
Andrew M. Kuchlingd6a1d792001-02-28 21:05:42 +0000195
Tim Peters1eff7962001-03-01 02:31:33 +0000196- New library module difflib.py, primarily packaging the SequenceMatcher
197 class at the heart of the popular ndiff.py file-comparison tool.
198
199- doctest.py (a framework for verifying Python code examples in docstrings)
200 is now part of the std library.
201
Tim Petersd66595f2001-02-04 03:09:53 +0000202Windows changes
203
Guido van Rossume3955a82001-03-02 14:05:59 +0000204- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
205 small GUI that lets you browse the module docstrings using your
206 default web browser.
207
Tim Peters1eff7962001-03-01 02:31:33 +0000208- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
209 Platforms) is implemented. See
210
211 http://python.sourceforge.net/peps/pep-0235.html
212
213 for full details, especially the "Current Lower-Left Semantics" section.
214 The new Windows import rules are simpler than before:
215
216 A. If the PYTHONCASEOK environment variable exists, same as
217 before: silently accept the first case-insensitive match of any
218 kind; raise ImportError if none found.
219
220 B. Else search sys.path for the first case-sensitive match; raise
221 ImportError if none found.
222
223 The same rules have been implented on other platforms with case-
224 insensitive but case-preserving filesystems too (including Cygwin, and
225 several flavors of Macintosh operating systems).
Tim Petersd66595f2001-02-04 03:09:53 +0000226
Tim Peters25a9ce32001-02-19 07:06:36 +0000227- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
228 what it's supposed to do (and does do under NT and 2000) via direct
229 port manipulation. It's unknown whether this will work on all systems,
Tim Peters1eff7962001-03-01 02:31:33 +0000230 but it does work on my Win98SE systems now and was known to be useless on
Tim Peters25a9ce32001-02-19 07:06:36 +0000231 all Win9x systems before.
232
Tim Peters1eff7962001-03-01 02:31:33 +0000233- Build: Subproject _test (effectively) renamed to _testcapi.
234
Tim Peters2fe289a2001-03-01 22:19:38 +0000235New platforms
236
237- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
238 Thanks to Steven Majewski!
239
240- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
241 Tishler!
242
Guido van Rossum9089b272001-03-02 06:49:50 +0000243- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
244 Schwertberger! See RISCOS/README for more information -- it seems
245 that because of the bizarre filename conventions on RISCOS, no port
246 to that platform is easy. Note that the new variable os.endsep is
247 silently supported in order to make life easier on this platform,
248 but we don't advertise it because it's not worth for most folks to
249 care about RISCOS portability.
250
Tim Peters25a9ce32001-02-19 07:06:36 +0000251
Tim Petersd7b5e882001-01-25 03:36:26 +0000252What's New in Python 2.1 alpha 2?
253=================================
Tim Peters40ead762001-01-27 05:35:26 +0000254
Tim Petersd7b5e882001-01-25 03:36:26 +0000255Core language, builtins, and interpreter
256
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000257- Scopes nest. If a name is used in a function or class, but is not
258 local, the definition in the nearest enclosing function scope will
259 be used. One consequence of this change is that lambda statements
260 could reference variables in the namespaces where the lambda is
261 defined. In some unusual cases, this change will break code.
262
263 In all previous version of Python, names were resolved in exactly
264 three namespaces -- the local namespace, the global namespace, and
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000265 the builtin namespace. According to this old definition, if a
Jeremy Hylton4589bd82001-02-01 20:38:45 +0000266 function A is defined within a function B, the names bound in B are
267 not visible in A. The new rules make names bound in B visible in A,
268 unless A contains a name binding that hides the binding in B.
269
270 Section 4.1 of the reference manual describes the new scoping rules
271 in detail. The test script in Lib/test/test_scope.py demonstrates
272 some of the effects of the change.
273
274 The new rules will cause existing code to break if it defines nested
275 functions where an outer function has local variables with the same
276 name as globals or builtins used by the inner function. Example:
277
278 def munge(str):
279 def helper(x):
280 return str(x)
281 if type(str) != type(''):
282 str = helper(str)
283 return str.strip()
284
285 Under the old rules, the name str in helper() is bound to the
286 builtin function str(). Under the new rules, it will be bound to
287 the argument named str and an error will occur when helper() is
288 called.
289
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000290- The compiler will report a SyntaxError if "from ... import *" occurs
291 in a function or class scope. The language reference has documented
292 that this case is illegal, but the compiler never checked for it.
293 The recent introduction of nested scope makes the meaning of this
294 form of name binding ambiguous. In a future release, the compiler
295 may allow this form when there is no possibility of ambiguity.
296
Tim Peters40ead762001-01-27 05:35:26 +0000297- repr(string) is easier to read, now using hex escapes instead of octal,
298 and using \t, \n and \r instead of \011, \012 and \015 (respectively):
299
300 >>> "\texample \r\n" + chr(0) + chr(255)
301 '\texample \r\n\x00\xff' # in 2.1
302 '\011example \015\012\000\377' # in 2.0
303
Moshe Zadka6af0ce02001-01-29 06:41:00 +0000304- Functions are now compared and hashed by identity, not by value, since
305 the func_code attribute is writable.
306
Fred Drakefb9d7122001-02-01 20:00:40 +0000307- Weak references (PEP 205) have been added. This involves a few
308 changes in the core, an extension module (_weakref), and a Python
309 module (weakref). The weakref module is the public interface. It
310 includes support for "explicit" weak references, proxy objects, and
311 mappings with weakly held values.
312
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000313- A 'continue' statement can now appear in a try block within the body
314 of a loop. It is still not possible to use continue in a finally
Tim Peters9ea17ac2001-02-02 05:57:15 +0000315 clause.
Jeremy Hylton0072d5a2001-02-01 22:53:15 +0000316
Tim Petersd7b5e882001-01-25 03:36:26 +0000317Standard library
318
Barry Warsaw30dbd142001-01-31 22:14:01 +0000319- mailbox.py now has a new class, PortableUnixMailbox which is
320 identical to UnixMailbox but uses a more portable scheme for
321 determining From_ separators. Also, the constructors for all the
322 classes in this module have a new optional `factory' argument, which
323 is a callable used when new message classes must be instantiated by
324 the next() method.
325
Tim Petersd7b5e882001-01-25 03:36:26 +0000326- random.py is now self-contained, and offers all the functionality of
327 the now-deprecated whrandom.py. See the docs for details. random.py
328 also supports new functions getstate() and setstate(), for saving
Tim Petersd52269b2001-01-25 06:23:18 +0000329 and restoring the internal state of the generator; and jumpahead(n),
330 for quickly forcing the internal state to be the same as if n calls to
331 random() had been made. The latter is particularly useful for multi-
332 threaded programs, creating one instance of the random.Random() class for
333 each thread, then using .jumpahead() to force each instance to use a
334 non-overlapping segment of the full period.
Tim Petersd7b5e882001-01-25 03:36:26 +0000335
Tim Peters0de88fc2001-02-01 04:59:18 +0000336- random.py's seed() function is new. For bit-for-bit compatibility with
337 prior releases, use the whseed function instead. The new seed function
338 addresses two problems: (1) The old function couldn't produce more than
339 about 2**24 distinct internal states; the new one about 2**45 (the best
340 that can be done in the Wichmann-Hill generator). (2) The old function
341 sometimes produced identical internal states when passed distinct
342 integers, and there was no simple way to predict when that would happen;
343 the new one guarantees to produce distinct internal states for all
344 arguments in [0, 27814431486576L).
345
Jeremy Hylton4c4fda02001-02-02 03:29:24 +0000346- The socket module now supports raw packets on Linux. The socket
347 family is AF_PACKET.
348
Tim Peters9ea17ac2001-02-02 05:57:15 +0000349- test_capi.py is a start at running tests of the Python C API. The tests
350 are implemented by the new Modules/_testmodule.c.
351
Jeremy Hyltond6b1cf92001-02-02 20:06:28 +0000352- A new extension module, _symtable, provides provisional access to the
353 internal symbol table used by the Python compiler. A higher-level
354 interface will be added on top of _symtable in a future release.
355
Andrew M. Kuchlingdebc3522001-02-22 15:53:21 +0000356- Removed the obsolete soundex module.
357
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000358- xml.dom.minidom now uses the standard DOM exceptions. Node supports
359 the isSameNode method; NamedNodeMap the get method.
360
361- xml.sax.expatreader supports the lexical handler property; it
362 generates comment, startCDATA, and endCDATA events.
363
Tim Petersee826f82001-01-31 19:39:44 +0000364Windows changes
365
366- Build procedure: the zlib project is built in a different way that
367 ensures the zlib header files used can no longer get out of synch with
Tim Peters9ea17ac2001-02-02 05:57:15 +0000368 the zlib binary used. See PCbuild\readme.txt for details. Your old
369 zlib-related directories can be deleted; you'll need to download fresh
370 source for zlib and unpack it into a new directory.
Tim Petersee826f82001-01-31 19:39:44 +0000371
Tim Peters9ea17ac2001-02-02 05:57:15 +0000372- Build: New subproject _test for the benefit of test_capi.py (see above).
373
Tim Petersb16c56f2001-02-02 21:24:51 +0000374- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
375 interface to some Python compiler internals).
376
377- Build: Subproject ucnhash is gone, since the code was folded into the
Tim Peters9ea17ac2001-02-02 05:57:15 +0000378 unicodedata subproject.
Tim Petersd7b5e882001-01-25 03:36:26 +0000379
Tim Petersa3a3a032000-11-30 05:22:44 +0000380What's New in Python 2.1 alpha 1?
381=================================
382
383Core language, builtins, and interpreter
384
Marc-André Lemburgebb195b2001-01-20 10:34:52 +0000385- There is a new Unicode companion to the PyObject_Str() API
386 called PyObject_Unicode(). It behaves in the same way as the
387 former, but assures that the returned value is an Unicode object
388 (applying the usual coercion if necessary).
Marc-André Lemburgad7c98e2001-01-17 17:09:53 +0000389
Guido van Rossumf98eda02001-01-17 15:54:45 +0000390- The comparison operators support "rich comparison overloading" (PEP
391 207). C extension types can provide a rich comparison function in
392 the new tp_richcompare slot in the type object. The cmp() function
393 and the C function PyObject_Compare() first try the new rich
394 comparison operators before trying the old 3-way comparison. There
395 is also a new C API PyObject_RichCompare() (which also falls back on
396 the old 3-way comparison, but does not constrain the outcome of the
397 rich comparison to a Boolean result).
398
399 The rich comparison function takes two objects (at least one of
400 which is guaranteed to have the type that provided the function) and
401 an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
402 Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
403 object, which may be NotImplemented (in which case the tp_compare
404 slot function is used as a fallback, if defined).
405
406 Classes can overload individual comparison operators by defining one
407 or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
Guido van Rossuma88479f2001-01-18 14:28:08 +0000408 __ge__. There are no explicit "reflected argument" versions of
409 these; instead, __lt__ and __gt__ are each other's reflection,
410 likewise for__le__ and __ge__; __eq__ and __ne__ are their own
411 reflection (similar at the C level). No other implications are
412 made; in particular, Python does not assume that == is the Boolean
413 inverse of !=, or that < is the Boolean inverse of >=. This makes
414 it possible to define types with partial orderings.
Guido van Rossumf98eda02001-01-17 15:54:45 +0000415
416 Classes or types that want to implement (in)equality tests but not
417 the ordering operators (i.e. unordered types) should implement ==
418 and !=, and raise an error for the ordering operators.
419
Guido van Rossuma88479f2001-01-18 14:28:08 +0000420 It is possible to define types whose rich comparison results are not
Guido van Rossumf98eda02001-01-17 15:54:45 +0000421 Boolean; e.g. a matrix type might want to return a matrix of bits
422 for A < B, giving elementwise comparisons. Such types should ensure
423 that any interpretation of their value in a Boolean context raises
424 an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
425 at the C level) to always raise an exception.
426
Guido van Rossuma88479f2001-01-18 14:28:08 +0000427- Complex numbers use rich comparisons to define == and != but raise
428 an exception for <, <=, > and >=. Unfortunately, this also means
429 that cmp() of two complex numbers raises an exception when the two
430 numbers differ. Since it is not mathematically meaningful to compare
431 complex numbers except for equality, I hope that this doesn't break
432 too much code.
433
Tim Peters3389f192001-02-18 08:48:49 +0000434- The outcome of comparing non-numeric objects of different types is
Tim Peters14495852001-02-18 08:28:33 +0000435 not defined by the language, other than that it's arbitrary but
436 consistent (see the Reference Manual). An implementation detail changed
437 in 2.1a1 such that None now compares less than any other object. Code
438 relying on this new behavior (like code that relied on the previous
439 behavior) does so at its own risk.
440
Barry Warsaw573b5412001-01-15 20:43:18 +0000441- Functions and methods now support getting and setting arbitrarily
442 named attributes (PEP 232). Functions have a new __dict__
443 (a.k.a. func_dict) which hold the function attributes. Methods get
444 and set attributes on their underlying im_func. It is a TypeError
445 to set an attribute on a bound method.
446
Guido van Rossum051e3352001-01-15 19:11:10 +0000447- The xrange() object implementation has been improved so that
448 xrange(sys.maxint) can be used on 64-bit platforms. There's still a
449 limitation that in this case len(xrange(sys.maxint)) can't be
450 calculated, but the common idiom "for i in xrange(sys.maxint)" will
451 work fine as long as the index i doesn't actually reach 2**31.
452 (Python uses regular ints for sequence and string indices; fixing
453 that is much more work.)
454
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000455- Two changes to from...import:
456
Guido van Rossumba381232001-02-03 15:06:40 +0000457 1) "from M import X" now works even if (after loading module M)
458 sys.modules['M'] is not a real module; it's basically a getattr()
459 operation with AttributeError exceptions changed into ImportError.
Guido van Rossum1cc8f832001-01-12 16:25:08 +0000460
461 2) "from M import *" now looks for M.__all__ to decide which names to
462 import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
463 filters out names starting with '_' as before. Whether or not
464 __all__ exists, there's no restriction on the type of M.
465
Guido van Rossumf61f1662001-01-10 20:13:55 +0000466- File objects have a new method, xreadlines(). This is the fastest
467 way to iterate over all lines in a file:
468
469 for line in file.xreadlines():
470 ...do something to line...
471
472 See the xreadlines module (mentioned below) for how to do this for
473 other file-like objects.
474
475- Even if you don't use file.xreadlines(), you may expect a speedup on
476 line-by-line input. The file.readline() method has been optimized
Tim Petersf29b64d2001-01-15 06:33:19 +0000477 quite a bit in platform-specific ways: on systems (like Linux) that
478 support flockfile(), getc_unlocked(), and funlockfile(), those are
479 used by default. On systems (like Windows) without getc_unlocked(),
480 a complicated (but still thread-safe) method using fgets() is used by
481 default.
482
Tim Petersd52269b2001-01-25 06:23:18 +0000483 You can force use of the fgets() method by #define'ing
484 USE_FGETS_IN_GETLINE at build time (it may be faster than
Tim Petersf29b64d2001-01-15 06:33:19 +0000485 getc_unlocked()).
486
Tim Petersd52269b2001-01-25 06:23:18 +0000487 You can force fgets() not to be used by #define'ing
488 DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
Tim Petersf29b64d2001-01-15 06:33:19 +0000489 test_bufio.py fails -- and let us know if it does!).
490
491- In addition, the fileinput module, while still slower than the other
492 methods on most platforms, has been sped up too, by using
493 file.readlines(sizehint).
Guido van Rossumf61f1662001-01-10 20:13:55 +0000494
495- Support for run-time warnings has been added, including a new
496 command line option (-W) to specify the disposition of warnings.
497 See the description of the warnings module below.
498
499- Extensive changes have been made to the coercion code. This mostly
500 affects extension modules (which can now implement mixed-type
501 numerical operators without having to use coercion), but
502 occasionally, in boundary cases the coercion semantics have changed
503 subtly. Since this was a terrible gray area of the language, this
Guido van Rossumae72d872001-01-11 15:00:14 +0000504 is considered an improvement. Also note that __rcmp__ is no longer
Guido van Rossumf61f1662001-01-10 20:13:55 +0000505 supported -- instead of calling __rcmp__, __cmp__ is called with
Guido van Rossuma88479f2001-01-18 14:28:08 +0000506 reflected arguments.
Guido van Rossumf61f1662001-01-10 20:13:55 +0000507
Guido van Rossumf98eda02001-01-17 15:54:45 +0000508- In connection with the coercion changes, a new built-in singleton
509 object, NotImplemented is defined. This can be returned for
510 operations that wish to indicate they are not implemented for a
511 particular combination of arguments. From C, this is
512 Py_NotImplemented.
513
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +0000514- The interpreter accepts now bytecode files on the command line even
515 if they do not have a .pyc or .pyo extension. On Linux, after executing
516
Martin v. Löwise214baa2001-02-04 22:37:56 +0000517import imp,sys,string
518magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
519reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
520open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
Martin v. Löwisbe4c0f52001-01-04 20:30:56 +0000521
522 any byte code file can be used as an executable (i.e. as an argument
523 to execve(2)).
524
Tim Peters9940b802000-12-01 07:59:35 +0000525- %[xXo] formats of negative Python longs now produce a sign
Tim Petersa3a3a032000-11-30 05:22:44 +0000526 character. In 1.6 and earlier, they never produced a sign,
527 and raised an error if the value of the long was too large
528 to fit in a Python int. In 2.0, they produced a sign if and
529 only if too large to fit in an int. This was inconsistent
530 across platforms (because the size of an int varies across
531 platforms), and inconsistent with hex() and oct(). Example:
532
533 >>> "%x" % -0x42L
Tim Peters9940b802000-12-01 07:59:35 +0000534 '-42' # in 2.1
Tim Petersa3a3a032000-11-30 05:22:44 +0000535 'ffffffbe' # in 2.0 and before, on 32-bit machines
536 >>> hex(-0x42L)
537 '-0x42L' # in all versions of Python
538
Tim Peters9940b802000-12-01 07:59:35 +0000539 The behavior of %d formats for negative Python longs remains
540 the same as in 2.0 (although in 1.6 and before, they raised
541 an error if the long didn't fit in a Python int).
542
543 %u formats don't make sense for Python longs, but are allowed
544 and treated the same as %d in 2.1. In 2.0, a negative long
545 formatted via %u produced a sign if and only if too large to
546 fit in an int. In 1.6 and earlier, a negative long formatted
547 via %u raised an error if it was too big to fit in an int.
548
Guido van Rossum3661d392000-12-12 22:10:31 +0000549- Dictionary objects have an odd new method, popitem(). This removes
550 an arbitrary item from the dictionary and returns it (in the form of
551 a (key, value) pair). This can be useful for algorithms that use a
552 dictionary as a bag of "to do" items and repeatedly need to pick one
553 item. Such algorithms normally end up running in quadratic time;
554 using popitem() they can usually be made to run in linear time.
555
Tim Peters36cdad12000-12-29 02:06:45 +0000556Standard library
557
Thomas Woutersfe385252001-01-19 23:16:56 +0000558- In the time module, the time argument to the functions strftime,
559 localtime, gmtime, asctime and ctime is now optional, defaulting to
560 the current time (in the local timezone).
561
Guido van Rossumda91f222001-01-15 16:36:08 +0000562- The ftplib module now defaults to passive mode, which is deemed a
563 more useful default given that clients are often inside firewalls
564 these days. Note that this could break if ftplib is used to connect
565 to a *server* that is inside a firewall, from outside; this is
566 expected to be a very rare situation. To fix that, you can call
567 ftp.set_pasv(0).
568
Martin v. Löwis10a27872001-01-13 09:54:41 +0000569- The module site now treats .pth files not only for path configuration,
570 but also supports extensions to the initialization code: Lines starting
571 with import are executed.
572
Guido van Rossumf61f1662001-01-10 20:13:55 +0000573- There's a new module, warnings, which implements a mechanism for
574 issuing and filtering warnings. There are some new built-in
575 exceptions that serve as warning categories, and a new command line
576 option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
577 turns warnings into errors). warnings.warn(message[, category])
578 issues a warning message; this can also be called from C as
579 PyErr_Warn(category, message).
580
581- A new module xreadlines was added. This exports a single factory
582 function, xreadlines(). The intention is that this code is the
583 absolutely fastest way to iterate over all lines in an open
584 file(-like) object:
585
586 import xreadlines
587 for line in xreadlines.xreadlines(file):
588 ...do something to line...
589
590 This is equivalent to the previous the speed record holder using
591 file.readlines(sizehint). Note that if file is a real file object
592 (as opposed to a file-like object), this is equivalent:
593
594 for line in file.xreadlines():
595 ...do something to line...
596
Tim Peters36cdad12000-12-29 02:06:45 +0000597- The bisect module has new functions bisect_left, insort_left,
598 bisect_right and insort_right. The old names bisect and insort
599 are now aliases for bisect_right and insort_right. XXX_right
600 and XXX_left methods differ in what happens when the new element
601 compares equal to one or more elements already in the list: the
602 XXX_left methods insert to the left, the XXX_right methods to the
Tim Peters742bb6f2001-01-05 08:05:32 +0000603 right. Code that doesn't care where equal elements end up should
604 continue to use the old, short names ("bisect" and "insort").
Tim Peters36cdad12000-12-29 02:06:45 +0000605
Andrew M. Kuchlingf6f3a892001-01-13 14:53:34 +0000606- The new curses.panel module wraps the panel library that forms part
607 of SYSV curses and ncurses. Contributed by Thomas Gellekum.
608
Guido van Rossumf61f1662001-01-10 20:13:55 +0000609- The SocketServer module now sets the allow_reuse_address flag by
610 default in the TCPServer class.
611
612- A new function, sys._getframe(), returns the stack frame pointer of
613 the caller. This is intended only as a building block for
614 higher-level mechanisms such as string interpolation.
615
Martin v. Löwis2a5130e2001-02-27 04:21:58 +0000616- The pyexpat module supports a number of new handlers, which are
617 available only in expat 1.2. If invocation of a callback fails, it
618 will report an additional frame in the traceback. Parser objects
619 participate now in garbage collection. If expat reports an unknown
620 encoding, pyexpat will try to use a Python codec; that works only
621 for single-byte charsets. The parser type objects is exposed as
622 XMLParserObject.
623
624- xml.dom now offers standard definitions for symbolic node type and
625 exception code constants, and a hierarchy of DOM exceptions. minidom
626 was adjusted to use them.
627
628- The conformance of xml.dom.minidom to the DOM specification was
629 improved. It detects a number of additional error cases; the
630 previous/next relationship works even when the tree is modified;
631 Node supports the normalize() method; NamedNodeMap, DocumentType and
632 DOMImplementation classes were added; Element supports the
633 hasAttribute and hasAttributeNS methods; and Text supports the splitText
634 method.
635
Guido van Rossumf61f1662001-01-10 20:13:55 +0000636Build issues
637
Guido van Rossum1e33bdc2001-01-23 03:17:00 +0000638- For Unix (and Unix-compatible) builds, configuration and building of
639 extension modules is now greatly automated. Rather than having to
640 edit the Modules/Setup file to indicate which modules should be
641 built and where their include files and libraries are, a
642 distutils-based setup.py script now takes care of building most
643 extension modules. All extension modules built this way are built
644 as shared libraries. Only a few modules that must be linked
645 statically are still listed in the Setup file; you won't need to
646 edit their configuration.
647
648- Python should now build out of the box on Cygwin. If it doesn't,
649 mail to Jason Tishler (jlt63 at users.sourceforge.net).
Guido van Rossumf61f1662001-01-10 20:13:55 +0000650
651- Python now always uses its own (renamed) implementation of getopt()
652 -- there's too much variation among C library getopt()
653 implementations.
654
655- C++ compilers are better supported; the CXX macro is always set to a
656 C++ compiler if one is found.
Tim Peters36cdad12000-12-29 02:06:45 +0000657
Tim Petersd92dfe02000-12-12 01:18:41 +0000658Windows changes
659
660- select module: By default under Windows, a select() call
661 can specify no more than 64 sockets. Python now boosts
662 this Microsoft default to 512. If you need even more than
663 that, see the MS docs (you'll need to #define FD_SETSIZE
664 and recompile Python from source).
665
Guido van Rossumf61f1662001-01-10 20:13:55 +0000666- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
667 subdirectory is no more!
668
Tim Petersa3a3a032000-11-30 05:22:44 +0000669
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000670What's New in Python 2.0?
Fred Drake1a640502000-10-16 20:27:25 +0000671=========================
Guido van Rossum61000331997-08-15 04:39:58 +0000672
Guido van Rossum8ed602b2000-09-01 22:34:33 +0000673Below is a list of all relevant changes since release 1.6. Older
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000674changes are in the file HISTORY. If you are making the jump directly
675from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
676HISTORY file! Many important changes listed there.
Guido van Rossum61000331997-08-15 04:39:58 +0000677
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000678Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
679the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
680http://starship.python.net/crew/amk/python/writing/new-python/.
Guido van Rossum1f83cce1997-10-06 21:04:35 +0000681
Guido van Rossumf2ffce02000-09-05 04:38:34 +0000682--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
Guido van Rossum437cfe81999-04-08 20:17:57 +0000683
684======================================================================
685
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000686What's new in 2.0 (since release candidate 1)?
687==============================================
688
689Standard library
690
691- The copy_reg module was modified to clarify its intended use: to
692 register pickle support for extension types, not for classes.
693 pickle() will raise a TypeError if it is passed a class.
694
695- Fixed a bug in gettext's "normalize and expand" code that prevented
696 it from finding an existing .mo file.
697
698- Restored support for HTTP/0.9 servers in httplib.
699
Tim Peters989b7b92000-10-16 20:24:53 +0000700- The math module was changed to stop raising OverflowError in case of
701 underflow, and return 0 instead in underflow cases. Whether Python
702 used to raise OverflowError in case of underflow was platform-
703 dependent (it did when the platform math library set errno to ERANGE
704 on underflow).
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000705
706- Fixed a bug in StringIO that occurred when the file position was not
707 at the end of the file and write() was called with enough data to
708 extend past the end of the file.
709
710- Fixed a bug that caused Tkinter error messages to get lost on
711 Windows. The bug was fixed by replacing direct use of
712 interp->result with Tcl_GetStringResult(interp).
713
714- Fixed bug in urllib2 that caused it to fail when it received an HTTP
715 redirect response.
716
717- Several changes were made to distutils: Some debugging code was
718 removed from util. Fixed the installer used when an external zip
719 program (like WinZip) is not found; the source code for this
720 installer is in Misc/distutils. check_lib() was modified to behave
721 more like AC_CHECK_LIB by add other_libraries() as a parameter. The
722 test for whether installed modules are on sys.path was changed to
723 use both normcase() and normpath().
724
Jeremy Hyltond867a2c2000-10-16 20:41:38 +0000725- Several minor bugs were fixed in the xml package (the minidom,
726 pulldom, expatreader, and saxutils modules).
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000727
728- The regression test driver (regrtest.py) behavior when invoked with
729 -l changed: It now reports a count of objects that are recognized as
730 garbage but not freed by the garbage collector.
731
Tim Peters989b7b92000-10-16 20:24:53 +0000732- The regression test for the math module was changed to test
733 exceptional behavior when the test is run in verbose mode. Python
734 cannot yet guarantee consistent exception behavior across platforms,
735 so the exception part of test_math is run only in verbose mode, and
736 may fail on your platform.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000737
738Internals
739
740- PyOS_CheckStack() has been disabled on Win64, where it caused
741 test_sre to fail.
742
743Build issues
744
745- Changed compiler flags, so that gcc is always invoked with -Wall and
746 -Wstrict-prototypes. Users compiling Python with GCC should see
747 exactly one warning, except if they have passed configure the
Tim Peters989b7b92000-10-16 20:24:53 +0000748 --with-pydebug flag. The expected warning is for getopt() in
Tim Petersadfb94f2000-10-16 20:51:33 +0000749 Modules/main.c. This warning will be fixed for Python 2.1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000750
Tim Petersa3a3a032000-11-30 05:22:44 +0000751- Fixed configure to add -threads argument during linking on OSF1.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000752
753Tools and other miscellany
754
755- The compiler in Tools/compiler was updated to support the new
756 language features introduced in 2.0: extended print statement, list
757 comprehensions, and augmented assignments. The new compiler should
758 also be backwards compatible with Python 1.5.2; the compiler will
759 always generate code for the version of the interpreter it runs
Tim Petersa3a3a032000-11-30 05:22:44 +0000760 under.
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000761
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000762What's new in 2.0 release candidate 1 (since beta 2)?
763=====================================================
764
Jeremy Hylton6040aaa2000-10-09 21:27:22 +0000765What is release candidate 1?
766
767We believe that release candidate 1 will fix all known bugs that we
768intend to fix for the 2.0 final release. This release should be a bit
769more stable than the previous betas. We would like to see even more
770widespread testing before the final release, so we are producing this
771release candidate. The final release will be exactly the same unless
772any show-stopping (or brown bag) bugs are found by testers of the
773release candidate.
774
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000775All the changes since the last beta release are bug fixes or changes
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000776to support building Python for specific platforms.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000777
778Core language, builtins, and interpreter
779
780- A bug that caused crashes when __coerce__ was used with augmented
781 assignment, e.g. +=, was fixed.
782
783- Raise ZeroDivisionError when raising zero to a negative number,
784 e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
785 power operator and the result of math.pow(0.0, -2.0) will vary by
786 platform. On Linux, it raises a ValueError.
787
788- A bug in Unicode string interpolation was fixed that occasionally
789 caused errors with formats including "%%". For example, the
790 following expression "%% %s" % u"abc" no longer raises a TypeError.
791
792- Compilation of deeply nested expressions raises MemoryError instead
793 of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
794
795- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
796 rendering them useless. They are now written in binary mode again.
797
798Standard library
799
800- Keyword arguments are now accepted for most pattern and match object
801 methods in SRE, the standard regular expression engine.
802
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000803- In SRE, fixed error with negative lookahead and lookbehind that
Jeremy Hylton32e20ff2000-10-09 19:48:11 +0000804 manifested itself as a runtime error in patterns like "(?<!abc)(def)".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000805
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000806- Several bugs in the Unicode handling and error handling in _tkinter
807 were fixed.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000808
809- Fix memory management errors in Merge() and Tkapp_Call() routines.
810
811- Several changes were made to cStringIO to make it compatible with
812 the file-like object interface and with StringIO. If operations are
813 performed on a closed object, an exception is raised. The truncate
814 method now accepts a position argument and readline accepts a size
Tim Petersa3a3a032000-11-30 05:22:44 +0000815 argument.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000816
817- There were many changes made to the linuxaudiodev module and its
818 test suite; as a result, a short, unexpected audio sample should now
Tim Petersa3a3a032000-11-30 05:22:44 +0000819 play when the regression test is run.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000820
821 Note that this module is named poorly, because it should work
822 correctly on any platform that supports the Open Sound System
Tim Petersa3a3a032000-11-30 05:22:44 +0000823 (OSS).
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000824
825 The module now raises exceptions when errors occur instead of
826 crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
827 audio) and defines a getptr() method that calls the
828 SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
829
830- The library_version attribute, introduced in an earlier beta, was
831 removed because it can not be supported with early versions of the C
832 readline library, which provides no way to determine the version at
833 compile-time.
834
835- The binascii module is now enabled on Win64.
836
Tim Peters46446d62000-10-09 21:19:31 +0000837- tokenize.py no longer suffers "recursion depth" errors when parsing
838 programs with very long string literals.
839
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000840Internals
841
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000842- Fixed several buffer overflow vulnerabilities in calculate_path(),
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000843 which is called when the interpreter starts up to determine where
844 the standard library is installed. These vulnerabilities affect all
845 previous versions of Python and can be exploited by setting very
846 long values for PYTHONHOME or argv[0]. The risk is greatest for a
847 setuid Python script, although use of the wrapper in
848 Misc/setuid-prog.c will eliminate the vulnerability.
849
850- Fixed garbage collection bugs in instance creation that were
851 triggered when errors occurred during initialization. The solution,
852 applied in cPickle and in PyInstance_New(), is to call
853 PyObject_GC_Init() after the initialization of the object's
854 container attributes is complete.
855
856- pyexpat adds definitions of PyModule_AddStringConstant and
857 PyModule_AddObject if the Python version is less than 2.0, which
858 provides compatibility with PyXML on Python 1.5.2.
859
860- If the platform has a bogus definition for LONG_BIT (the number of
861 bits in a long), an error will be reported at compile time.
862
863- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
864 collection crashes and possibly other, unreported crashes.
865
866- Fixed a memory leak in _PyUnicode_Fini().
867
868Build issues
869
870- configure now accepts a --with-suffix option that specifies the
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000871 executable suffix. This is useful for builds on Cygwin and Mac OS
Tim Petersa3a3a032000-11-30 05:22:44 +0000872 X, for example.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000873
874- The mmap.PAGESIZE constant is now initialized using sysconf when
875 possible, which eliminates a dependency on -lucb for Reliant UNIX.
876
877- The md5 file should now compile on all platforms.
878
879- The select module now compiles on platforms that do not define
880 POLLRDNORM and related constants.
881
882- Darwin (Mac OS X): Initial support for static builds on this
Tim Petersa3a3a032000-11-30 05:22:44 +0000883 platform.
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000884
Jeremy Hylton10921202000-10-09 18:34:12 +0000885- BeOS: A number of changes were made to the build and installation
886 process. ar-fake now operates on a directory of object files.
887 dl_export.h is gone, and its macros now appear on the mwcc command
888 line during build on PPC BeOS.
889
Jeremy Hyltond6e20232000-10-16 20:08:38 +0000890- Platform directory in lib/python2.0 is "plat-beos5" (or
Jeremy Hylton10921202000-10-09 18:34:12 +0000891 "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
Jeremy Hyltoned9e6442000-10-09 18:26:42 +0000892
893- Cygwin: Support for shared libraries, Tkinter, and sockets.
894
895- SunOS 4.1.4_JL: Fix test for directory existence in configure.
896
897Tools and other miscellany
898
899- Removed debugging prints from main used with freeze.
900
Tim Peters46446d62000-10-09 21:19:31 +0000901- IDLE auto-indent no longer crashes when it encounters Unicode
902 characters.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000903
904What's new in 2.0 beta 2 (since beta 1)?
905========================================
906
907Core language, builtins, and interpreter
908
Tim Peters482c0212000-09-26 06:33:09 +0000909- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000910 "%d" % 2L**64 == "18446744073709551616".
Jeremy Hylton1b618592000-09-26 05:32:36 +0000911
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000912- Add -h and -V command line options to print the usage message and
913 Python version number and exit immediately.
914
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +0000915- eval() and exec accept Unicode objects as code parameters.
916
917- getattr() and setattr() now also accept Unicode objects for the
918 attribute name, which are converted to strings using the default
919 encoding before lookup.
920
921- Multiplication on string and Unicode now does proper bounds
922 checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
923 string is too long."
924
925- Better error message when continue is found in try statement in a
Tim Petersa3a3a032000-11-30 05:22:44 +0000926 loop.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +0000927
Jeremy Hylton1b618592000-09-26 05:32:36 +0000928
929Standard library and extensions
930
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000931- array: reverse() method of array now works. buffer_info() now does
Jeremy Hylton1b618592000-09-26 05:32:36 +0000932 argument checking; it still takes no arguments.
933
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000934- asyncore/asynchat: Included most recent version from Sam Rushing.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000935
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000936- cgi: Accept '&' or ';' as separator characters when parsing form data.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000937
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000938- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
Jeremy Hylton1b618592000-09-26 05:32:36 +0000939
940- ConfigParser: When reading the file, options spelled in upper case
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000941 letters are now correctly converted to lowercase.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000942
943- copy: Copy Unicode objects atomically.
944
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000945- cPickle: Fail gracefully when copy_reg can't be imported.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000946
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000947- cStringIO: Implemented readlines() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000948
Fred Drake67233bc2000-09-26 16:40:27 +0000949- dbm: Add get() and setdefault() methods to dbm object. Add constant
950 `library' to module that names the library used. Added doc strings
951 and method names to error messages. Uses configure to determine
952 which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
953 now available options.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000954
955- distutils: Update to version 0.9.3.
956
957- dl: Add several dl.RTLD_ constants.
958
959- fpectl: Now supported on FreeBSD.
960
961- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
962 found by the collector will be saved in gc.garbage. This is useful
963 for debugging a program that creates reference cycles.
964
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000965- httplib: Three changes: Restore support for set_debuglevel feature
Jeremy Hylton1b618592000-09-26 05:32:36 +0000966 of HTTP class. Do not close socket on zero-length response. Do not
967 crash when server sends invalid content-length header.
968
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000969- mailbox: Mailbox class conforms better to qmail specifications.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000970
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +0000971- marshal: When reading a short, sign-extend on platforms where shorts
972 are bigger than 16 bits. When reading a long, repair the unportable
973 sign extension that was being done for 64-bit machines. (It assumed
974 that signed right shift sign-extends.)
975
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000976- operator: Add contains(), invert(), __invert__() as aliases for
977 __contains__(), inv(), and __inv__() respectively.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000978
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000979- os: Add support for popen2() and popen3() on all platforms where
980 fork() exists. (popen4() is still in the works.)
Jeremy Hylton1b618592000-09-26 05:32:36 +0000981
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000982- os: (Windows only:) Add startfile() function that acts like double-
Tim Peters482c0212000-09-26 06:33:09 +0000983 clicking on a file in Explorer (or passing the file name to the
984 DOS "start" command).
Jeremy Hylton1b618592000-09-26 05:32:36 +0000985
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000986- os.path: (Windows, DOS:) Treat trailing colon correctly in
Tim Peters482c0212000-09-26 06:33:09 +0000987 os.path.join. os.path.join("a:", "b") yields "a:b".
Jeremy Hylton1b618592000-09-26 05:32:36 +0000988
989- pickle: Now raises ValueError when an invalid pickle that contains
990 a non-string repr where a string repr was expected. This behavior
991 matches cPickle.
992
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000993- posixfile: Remove broken __del__() method.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000994
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000995- py_compile: support CR+LF line terminators in source file.
Jeremy Hylton1b618592000-09-26 05:32:36 +0000996
997- readline: Does not immediately exit when ^C is hit when readline and
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +0000998 threads are configured. Adds definition of rl_library_version. (The
Guido van Rossumf62ed9c2000-09-26 11:16:10 +0000999 latter addition requires GNU readline 2.2 or later.)
Jeremy Hylton1b618592000-09-26 05:32:36 +00001000
1001- rfc822: Domain literals returned by AddrlistClass method
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001002 getdomainliteral() are now properly wrapped in brackets.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001003
1004- site: sys.setdefaultencoding() should only be called in case the
Tim Peters482c0212000-09-26 06:33:09 +00001005 standard default encoding ("ascii") is changed. This saves quite a
Jeremy Hylton1b618592000-09-26 05:32:36 +00001006 few cycles during startup since the first call to
1007 setdefaultencoding() will initialize the codec registry and the
1008 encodings package.
1009
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001010- socket: Support for size hint in readlines() method of object returned
1011 by makefile().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001012
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001013- sre: Added experimental expand() method to match objects. Does not
Jeremy Hylton625915e2000-10-02 13:43:33 +00001014 use buffer interface on Unicode strings. Does not hang if group id
Jeremy Hylton1b618592000-09-26 05:32:36 +00001015 is followed by whitespace.
1016
Tim Petersa3a3a032000-11-30 05:22:44 +00001017- StringIO: Size hint in readlines() is now supported as documented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001018
1019- struct: Check ranges for bytes and shorts.
1020
1021- urllib: Improved handling of win32 proxy settings. Fixed quote and
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001022 quote_plus functions so that the always encode a comma.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001023
1024- Tkinter: Image objects are now guaranteed to have unique ids. Set
1025 event.delta to zero if Tk version doesn't support mousewheel.
1026 Removed some debugging prints.
1027
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001028- UserList: now implements __contains__().
Jeremy Hylton1b618592000-09-26 05:32:36 +00001029
Fred Drake67233bc2000-09-26 16:40:27 +00001030- webbrowser: On Windows, use os.startfile() instead of os.popen(),
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001031 which works around a bug in Norton AntiVirus 2000 that leads directly
1032 to a Blue Screen freeze.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001033
1034- xml: New version detection code allows PyXML to override standard
1035 XML package if PyXML version is greater than 0.6.1.
1036
Fred Drake64bb3802000-09-26 16:21:35 +00001037- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
1038 (conventional DOM), and xml.dom.pulldom, which allows building the DOM
1039 tree only for nodes which are sufficiently interesting to a specific
1040 application. Does not provide the HTML-specific extensions. Still
1041 undocumented.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001042
Fred Drake64bb3802000-09-26 16:21:35 +00001043- xml.sax: SAX 2 support for Python, including all the handler
1044 interfaces needed to process XML 1.0 compliant XML. Some
1045 documentation is already available.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001046
Fred Drake64bb3802000-09-26 16:21:35 +00001047- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
1048 packagized XML support.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001049
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001050
Jeremy Hylton1b618592000-09-26 05:32:36 +00001051C API
1052
1053- Add three new convenience functions for module initialization --
1054 PyModule_AddObject(), PyModule_AddIntConstant(), and
1055 PyModule_AddStringConstant().
1056
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001057- Cleaned up definition of NULL in C source code; all definitions were
Jeremy Hylton1b618592000-09-26 05:32:36 +00001058 removed and add #error to Python.h if NULL isn't defined after
1059 #include of stdio.h.
1060
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001061- Py_PROTO() macros that were removed in 2.0b1 have been restored for
Jeremy Hylton1b618592000-09-26 05:32:36 +00001062 backwards compatibility (at the source level) with old extensions.
1063
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001064- A wrapper API was added for signal() and sigaction(). Instead of
1065 either function, always use PyOS_getsig() to get a signal handler
1066 and PyOS_setsig() to set one. A new convenience typedef
1067 PyOS_sighandler_t is defined for the type of signal handlers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001068
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001069- Add PyString_AsStringAndSize() function that provides access to the
Jeremy Hylton1b618592000-09-26 05:32:36 +00001070 internal data buffer and size of a string object -- or the default
1071 encoded version of a Unicode object.
1072
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001073- PyString_Size() and PyString_AsString() accept Unicode objects.
1074
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001075- The standard header <limits.h> is now included by Python.h (if it
Fred Drake64bb3802000-09-26 16:21:35 +00001076 exists). INT_MAX and LONG_MAX will always be defined, even if
1077 <limits.h> is not available.
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001078
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001079- PyFloat_FromString takes a second argument, pend, that was
1080 effectively useless. It is now officially useless but preserved for
1081 backwards compatibility. If the pend argument is not NULL, *pend is
1082 set to NULL.
1083
1084- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
1085 for the attribute name. See note on getattr() above.
1086
1087- A few bug fixes to argument processing for Unicode.
1088 PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
1089 PyArg_Parse() special cases "s#" for Unicode objects; it returns a
1090 pointer to the default encoded string data instead of to the raw
Tim Petersa3a3a032000-11-30 05:22:44 +00001091 UTF-16.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001092
1093- Py_BuildValue accepts B format (for bgen-generated code).
1094
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001095
Jeremy Hylton1b618592000-09-26 05:32:36 +00001096Internals
1097
1098- On Unix, fix code for finding Python installation directory so that
1099 it works when argv[0] is a relative path.
1100
Andrew M. Kuchlinga1099be2000-12-15 01:16:43 +00001101- Added a true unicode_internal_encode() function and fixed the
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001102 unicode_internal_decode function() to support Unicode objects directly
Jeremy Hylton1b618592000-09-26 05:32:36 +00001103 rather than by generating a copy of the object.
1104
Tim Peters482c0212000-09-26 06:33:09 +00001105- Several of the internal Unicode tables are much smaller now, and
1106 the source code should be much friendlier to weaker compilers.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001107
Jeremy Hylton97693b02000-09-26 17:42:51 +00001108- In the garbage collector: Fixed bug in collection of tuples. Fixed
1109 bug that caused some instances to be removed from the container set
1110 while they were still live. Fixed parsing in gc.set_debug() for
1111 platforms where sizeof(long) > sizeof(int).
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001112
1113- Fixed refcount problem in instance deallocation that only occurred
1114 when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
1115
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001116- On Windows, getpythonregpath is now protected against null data in
1117 registry key.
1118
1119- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
Tim Petersa3a3a032000-11-30 05:22:44 +00001120 condition.
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001121
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001122
Jeremy Hylton1b618592000-09-26 05:32:36 +00001123Build and platform-specific issues
1124
1125- Better support of GNU Pth via --with-pth configure option.
1126
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001127- Python/C API now properly exposed to dynamically-loaded extension
1128 modules on Reliant UNIX.
Jeremy Hylton1b618592000-09-26 05:32:36 +00001129
1130- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
1131 Don't define MS_SYNC to be zero when it is undefined. Added missing
1132 prototypes in posixmodule.c.
1133
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001134- Improved support for HP-UX build. Threads should now be correctly
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001135 configured (on HP-UX 10.20 and 11.00).
Jeremy Hylton1b618592000-09-26 05:32:36 +00001136
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001137- Fix largefile support on older NetBSD systems and OpenBSD by adding
1138 define for TELL64.
1139
1140
1141Tools and other miscellany
1142
1143- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
1144
1145- freeze: The modulefinder now works with 2.0 opcodes.
1146
Tim Petersa3a3a032000-11-30 05:22:44 +00001147- IDLE:
Jeremy Hyltonfa2e2c12000-09-26 16:31:30 +00001148 Move hackery of sys.argv until after the Tk instance has been
1149 created, which allows the application-specific Tkinter
1150 initialization to be executed if present; also pass an explicit
1151 className parameter to the Tk() constructor.
Fred Drake64bb3802000-09-26 16:21:35 +00001152
Jeremy Hylton1b618592000-09-26 05:32:36 +00001153
1154What's new in 2.0 beta 1?
1155=========================
1156
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001157Source Incompatibilities
1158------------------------
1159
1160None. Note that 1.6 introduced several incompatibilities with 1.5.2,
1161such as single-argument append(), connect() and bind(), and changes to
1162str(long) and repr(float).
1163
1164
1165Binary Incompatibilities
1166------------------------
1167
1168- Third party extensions built for Python 1.5.x or 1.6 cannot be used
1169with Python 2.0; these extensions will have to be rebuilt for Python
11702.0.
1171
1172- On Windows, attempting to import a third party extension built for
1173Python 1.5.x or 1.6 results in an immediate crash; there's not much we
1174can do about this. Check your PYTHONPATH environment variable!
1175
1176- Python bytecode files (*.pyc and *.pyo) are not compatible between
1177releases.
1178
1179
1180Overview of Changes Since 1.6
1181-----------------------------
1182
1183There are many new modules (including brand new XML support through
1184the xml package, and i18n support through the gettext module); a list
1185of all new modules is included below. Lots of bugs have been fixed.
1186
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001187The process for making major new changes to the language has changed
1188since Python 1.6. Enhancements must now be documented by a Python
1189Enhancement Proposal (PEP) before they can be accepted.
1190
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001191There are several important syntax enhancements, described in more
1192detail below:
1193
1194 - Augmented assignment, e.g. x += 1
1195
1196 - List comprehensions, e.g. [x**2 for x in range(10)]
1197
1198 - Extended import statement, e.g. import Module as Name
1199
1200 - Extended print statement, e.g. print >> file, "Hello"
1201
1202Other important changes:
1203
1204 - Optional collection of cyclical garbage
1205
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001206Python Enhancement Proposal (PEP)
1207---------------------------------
1208
1209PEP stands for Python Enhancement Proposal. A PEP is a design
1210document providing information to the Python community, or describing
1211a new feature for Python. The PEP should provide a concise technical
1212specification of the feature and a rationale for the feature.
1213
1214We intend PEPs to be the primary mechanisms for proposing new
1215features, for collecting community input on an issue, and for
1216documenting the design decisions that have gone into Python. The PEP
1217author is responsible for building consensus within the community and
1218documenting dissenting opinions.
1219
1220The PEPs are available at http://python.sourceforge.net/peps/.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001221
1222Augmented Assignment
1223--------------------
1224
1225This must have been the most-requested feature of the past years!
1226Eleven new assignment operators were added:
1227
Guido van Rossume905e952000-09-05 12:42:46 +00001228 += -= *= /= %= **= <<= >>= &= ^= |=
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001229
1230For example,
1231
1232 A += B
1233
1234is similar to
1235
1236 A = A + B
1237
1238except that A is evaluated only once (relevant when A is something
1239like dict[index].attr).
1240
1241However, if A is a mutable object, A may be modified in place. Thus,
1242if A is a number or a string, A += B has the same effect as A = A+B
1243(except A is only evaluated once); but if a is a list, A += B has the
1244same effect as A.extend(B)!
1245
1246Classes and built-in object types can override the new operators in
1247order to implement the in-place behavior; the not-in-place behavior is
1248used automatically as a fallback when an object doesn't implement the
1249in-place behavior. For classes, the method name is derived from the
1250method name for the corresponding not-in-place operator by inserting
1251an 'i' in front of the name, e.g. __iadd__ implements in-place
1252__add__.
1253
1254Augmented assignment was implemented by Thomas Wouters.
1255
1256
1257List Comprehensions
1258-------------------
1259
1260This is a flexible new notation for lists whose elements are computed
1261from another list (or lists). The simplest form is:
1262
1263 [<expression> for <variable> in <sequence>]
1264
Guido van Rossum56db0952000-09-06 23:34:25 +00001265For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001266This is more efficient than a for loop with a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001267
1268You can also add a condition:
1269
1270 [<expression> for <variable> in <sequence> if <condition>]
1271
1272For example, [w for w in words if w == w.lower()] would yield the list
1273of words that contain no uppercase characters. This is more efficient
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001274than a for loop with an if statement and a list.append() call.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001275
1276You can also have nested for loops and more than one 'if' clause. For
1277example, here's a function that flattens a sequence of sequences::
1278
1279 def flatten(seq):
1280 return [x for subseq in seq for x in subseq]
1281
1282 flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
1283
1284This prints
1285
1286 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
1287
1288List comprehensions originated as a patch set from Greg Ewing; Skip
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001289Montanaro and Thomas Wouters also contributed. Described by PEP 202.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001290
1291
1292Extended Import Statement
1293-------------------------
1294
1295Many people have asked for a way to import a module under a different
1296name. This can be accomplished like this:
1297
1298 import foo
1299 bar = foo
1300 del foo
1301
1302but this common idiom gets old quickly. A simple extension of the
1303import statement now allows this to be written as follows:
1304
1305 import foo as bar
1306
1307There's also a variant for 'from ... import':
1308
1309 from foo import bar as spam
1310
1311This also works with packages; e.g. you can write this:
1312
1313 import test.regrtest as regrtest
1314
1315Note that 'as' is not a new keyword -- it is recognized only in this
1316context (this is only possible because the syntax for the import
1317statement doesn't involve expressions).
1318
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001319Implemented by Thomas Wouters. Described by PEP 221.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001320
1321
1322Extended Print Statement
1323------------------------
1324
1325Easily the most controversial new feature, this extension to the print
1326statement adds an option to make the output go to a different file
1327than the default sys.stdout.
1328
1329For example, to write an error message to sys.stderr, you can now
1330write:
1331
1332 print >> sys.stderr, "Error: bad dog!"
1333
1334As a special feature, if the expression used to indicate the file
Fred Drake45888ff2000-09-29 17:09:11 +00001335evaluates to None, the current value of sys.stdout is used. Thus:
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001336
1337 print >> None, "Hello world"
1338
1339is equivalent to
1340
1341 print "Hello world"
1342
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001343Design and implementation by Barry Warsaw. Described by PEP 214.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001344
1345
1346Optional Collection of Cyclical Garbage
1347---------------------------------------
1348
1349Python is now equipped with a garbage collector that can hunt down
1350cyclical references between Python objects. It's no replacement for
1351reference counting; in fact, it depends on the reference counts being
1352correct, and decides that a set of objects belong to a cycle if all
1353their reference counts can be accounted for from their references to
1354each other. This devious scheme was first proposed by Eric Tiedemann,
1355and brought to implementation by Neil Schemenauer.
1356
1357There's a module "gc" that lets you control some parameters of the
1358garbage collection. There's also an option to the configure script
1359that lets you enable or disable the garbage collection. In 2.0b1,
1360it's on by default, so that we (hopefully) can collect decent user
1361experience with this new feature. There are some questions about its
Fred Drake9f11cf82000-09-29 17:54:40 +00001362performance. If it proves to be too much of a problem, we'll turn it
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001363off by default in the final 2.0 release.
1364
1365
1366Smaller Changes
1367---------------
1368
1369A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
1370map(None, seq1, seq2, ...) when the sequences have the same length;
1371i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
1372the lists are not all the same length, the shortest list wins:
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001373zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001374
1375sys.version_info is a tuple (major, minor, micro, level, serial).
1376
1377Dictionaries have an odd new method, setdefault(key, default).
1378dict.setdefault(key, default) returns dict[key] if it exists; if not,
1379it sets dict[key] to default and returns that value. Thus:
1380
1381 dict.setdefault(key, []).append(item)
1382
1383does the same work as this common idiom:
1384
1385 if not dict.has_key(key):
1386 dict[key] = []
1387 dict[key].append(item)
1388
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001389There are two new variants of SyntaxError that are raised for
1390indentation-related errors: IndentationError and TabError.
1391
1392Changed \x to consume exactly two hex digits; see PEP 223. Added \U
1393escape that consumes exactly eight hex digits.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001394
1395The limits on the size of expressions and file in Python source code
1396have been raised from 2**16 to 2**32. Previous versions of Python
1397were limited because the maximum argument size the Python VM accepted
1398was 2**16. This limited the size of object constructor expressions,
1399e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
1400limit was raised thanks to a patch by Charles Waldman that effectively
1401fixes the problem. It is now much more likely that you will be
1402limited by available memory than by an arbitrary limit in Python.
1403
1404The interpreter's maximum recursion depth can be modified by Python
1405programs using sys.getrecursionlimit and sys.setrecursionlimit. This
1406limit is the maximum number of recursive calls that can be made by
1407Python code. The limit exists to prevent infinite recursion from
1408overflowing the C stack and causing a core dump. The default value is
14091000. The maximum safe value for a particular platform can be found
1410by running Misc/find_recursionlimit.py.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001411
1412New Modules and Packages
1413------------------------
1414
1415atexit - for registering functions to be called when Python exits.
1416
1417imputil - Greg Stein's alternative API for writing custom import
1418hooks.
1419
1420pyexpat - an interface to the Expat XML parser, contributed by Paul
1421Prescod.
1422
1423xml - a new package with XML support code organized (so far) in three
1424subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
1425would fill a volume. There's a special feature whereby a
1426user-installed package named _xmlplus overrides the standard
1427xmlpackage; this is intended to give the XML SIG a hook to distribute
1428backwards-compatible updates to the standard xml package.
1429
1430webbrowser - a platform-independent API to launch a web browser.
1431
1432
Guido van Rossume905e952000-09-05 12:42:46 +00001433Changed Modules
1434---------------
1435
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001436array -- new methods for array objects: count, extend, index, pop, and
1437remove
1438
1439binascii -- new functions b2a_hex and a2b_hex that convert between
1440binary data and its hex representation
1441
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001442calendar -- Many new functions that support features including control
1443over which day of the week is the first day, returning strings instead
1444of printing them. Also new symbolic constants for days of week,
1445e.g. MONDAY, ..., SUNDAY.
1446
1447cgi -- FieldStorage objects have a getvalue method that works like a
1448dictionary's get method and returns the value attribute of the object.
1449
1450ConfigParser -- The parser object has new methods has_option,
1451remove_section, remove_option, set, and write. They allow the module
1452to be used for writing config files as well as reading them.
1453
1454ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
Guido van Rossume905e952000-09-05 12:42:46 +00001455optionally support the RFC 959 REST command.
1456
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001457gzip -- readline and readlines now accept optional size arguments
Guido van Rossume905e952000-09-05 12:42:46 +00001458
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001459httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
1460the module doc strings for details.
Guido van Rossum830ca2a2000-09-05 15:34:16 +00001461
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001462locale -- implement getdefaultlocale for Win32 and Macintosh
1463
1464marshal -- no longer dumps core when marshaling deeply nested or
1465recursive data structures
1466
1467os -- new functions isatty, seteuid, setegid, setreuid, setregid
1468
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001469os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
1470support under Unix.
1471
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001472os/pty -- support for openpty and forkpty
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001473
1474os.path -- fix semantics of os.path.commonprefix
1475
1476smtplib -- support for sending very long messages
1477
1478socket -- new function getfqdn()
1479
1480readline -- new functions to read, write and truncate history files.
1481The readline section of the library reference manual contains an
1482example.
1483
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001484select -- add interface to poll system call
1485
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001486shutil -- new copyfileobj function
1487
1488SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
1489HTTP server.
1490
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001491Tkinter -- optimization of function flatten
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001492
1493urllib -- scans environment variables for proxy configuration,
Tim Peters8b092332000-09-05 20:15:25 +00001494e.g. http_proxy.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001495
1496whichdb -- recognizes dumbdbm format
Guido van Rossume905e952000-09-05 12:42:46 +00001497
1498
1499Obsolete Modules
1500----------------
1501
1502None. However note that 1.6 made a whole slew of modules obsolete:
1503stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
1504poly, zmod, strop, util, whatsound.
1505
1506
1507Changed, New, Obsolete Tools
1508----------------------------
1509
Tim Peters8b092332000-09-05 20:15:25 +00001510None.
Guido van Rossume905e952000-09-05 12:42:46 +00001511
1512
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001513C-level Changes
1514---------------
1515
1516Several cleanup jobs were carried out throughout the source code.
1517
1518All C code was converted to ANSI C; we got rid of all uses of the
1519Py_PROTO() macro, which makes the header files a lot more readable.
1520
1521Most of the portability hacks were moved to a new header file,
1522pyport.h; several other new header files were added and some old
1523header files were removed, in an attempt to create a more rational set
1524of header files. (Few of these ever need to be included explicitly;
1525they are all included by Python.h.)
1526
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001527Trent Mick ensured portability to 64-bit platforms, under both Linux
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001528and Win64, especially for the new Intel Itanium processor. Mick also
1529added large file support for Linux64 and Win64.
Guido van Rossumf2ffce02000-09-05 04:38:34 +00001530
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001531The C APIs to return an object's size have been update to consistently
1532use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
1533previous versions, the abstract interfaces used PyXXX_Length and the
1534concrete interfaces used PyXXX_Size. The old names,
1535e.g. PyObject_Length, are still available for backwards compatibility
1536at the API level, but are deprecated.
1537
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001538The PyOS_CheckStack function has been implemented on Windows by
1539Fredrik Lundh. It prevents Python from failing with a stack overflow
1540on Windows.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001541
1542The GC changes resulted in creation of two new slots on object,
1543tp_traverse and tp_clear. The augmented assignment changes result in
Guido van Rossum4338a282000-09-06 13:02:08 +00001544the creation of a new slot for each in-place operator.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001545
1546The GC API creates new requirements for container types implemented in
Guido van Rossum4338a282000-09-06 13:02:08 +00001547C extension modules. See Include/objimpl.h for details.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001548
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001549PyErr_Format has been updated to automatically calculate the size of
1550the buffer needed to hold the formatted result string. This change
1551prevents crashes caused by programmer error.
Jeremy Hyltonbdebd542000-09-05 18:28:54 +00001552
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001553New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
Guido van Rossume905e952000-09-05 12:42:46 +00001554
Jeremy Hylton24c3d602000-09-05 19:36:26 +00001555PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
1556that are the same as their non-Ex counterparts except they take an
1557extra flag argument that tells them to close the file when done.
1558
1559XXX There were other API changes that should be fleshed out here.
Guido van Rossumab9d6f01998-08-10 22:01:13 +00001560
Tim Peters8b092332000-09-05 20:15:25 +00001561
1562Windows Changes
1563---------------
1564
1565New popen2/popen3/peopen4 in os module (see Changed Modules above).
1566
1567os.popen is much more usable on Windows 95 and 98. See Microsoft
1568Knowledge Base article Q150956. The Win9x workaround described there
1569is implemented by the new w9xpopen.exe helper in the root of your
1570Python installation. Note that Python uses this internally; it is not
1571a standalone program.
1572
1573Administrator privileges are no longer required to install Python
1574on Windows NT or Windows 2000. If you have administrator privileges,
1575Python's registry info will be written under HKEY_LOCAL_MACHINE.
1576Otherwise the installer backs off to writing Python's registry info
Guido van Rossum4338a282000-09-06 13:02:08 +00001577under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
Tim Peters8b092332000-09-05 20:15:25 +00001578uses of Python, but will prevent some advanced uses from working
1579(for example, running a Python script as an NT service, or possibly
1580from CGI).
1581
1582[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
1583installer; instead, it installs the needed Tcl/Tk files directly in the
1584Python directory. If you already have a Tcl/Tk installation, this
1585wastes some disk space (about 4 Megs) but avoids problems with
1586conflicting Tcl/Tk installations, and makes it much easier for Python
1587to ensure that Tcl/Tk can find all its files.
1588
1589[This was new in 1.6] The Windows installer now installs by default in
1590\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
1591
Guido van Rossumf62ed9c2000-09-26 11:16:10 +00001592
1593Updates to the changes between 1.5.2 and 1.6
1594--------------------------------------------
1595
1596The 1.6 NEWS file can't be changed after the release is done, so here
1597is some late-breaking news:
1598
1599New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
1600and changes to getlocale() and setlocale().
1601
1602The new module is now enabled per default.
1603
1604It is not true that the encodings codecs cannot be used for normal
1605strings: the string.encode() (which is also present on 8-bit strings
1606!) allows using them for 8-bit strings too, e.g. to convert files from
1607cp1252 (Windows) to latin-1 or vice-versa.
1608
1609Japanese codecs are available from Tamito KAJIYAMA:
1610http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
1611
1612
Guido van Rossumab9d6f01998-08-10 22:01:13 +00001613======================================================================