======================================================================
+What's New in Python 2.1 (final)?
+=================================
+
+We only changed a few things since the last release candidate, all in
+Python library code:
+
+- A bug in the locale module was fixed that affected locales which
+ define no grouping for numeric formatting.
+
+- A few bugs in the weakref module's implementations of weak
+ dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
+ and the test suite was updated to check for these bugs.
+
+- An old bug in the os.path.walk() function (introduced in Python
+ 2.0!) was fixed: a non-existent file would cause an exception
+ instead of being ignored.
+
+- Fixed a few bugs in the new symtable module found by Neil Norwitz's
+ PyChecker.
+
+
+What's New in Python 2.1c2?
+===========================
+
+A flurry of small changes, and one showstopper fixed in the nick of
+time made it necessary to release another release candidate. The list
+here is the *complete* list of patches (except version updates):
+
+Core
+
+- Tim discovered a nasty bug in the dictionary code, caused by
+ PyDict_Next() calling dict_resize(), and the GC code's use of
+ PyDict_Next() violating an assumption in dict_items(). This was
+ fixed with considerable amounts of band-aid, but the net effect is a
+ saner and more robust implementation.
+
+- Made a bunch of symbols static that were accidentally global.
+
+Build and Ports
+
+- The setup.py script didn't check for a new enough version of zlib
+ (1.1.3 is needed). Now it does.
+
+- Changed "make clean" target to also remove shared libraries.
+
+- Added a more general warning about the SGI Irix optimizer to README.
+
+Library
+
+- Fix a bug in urllib.basejoin("http://host", "../file.html") which
+ omitted the slash between host and file.html.
+
+- The mailbox module's _Mailbox class contained a completely broken
+ and undocumented seek() method. Ripped it out.
+
+- Fixed a bunch of typos in various library modules (urllib2, smtpd,
+ sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
+
+- Fixed a few last-minute bugs in unittest.
+
+Extensions
+
+- Reverted the patch to the OpenSSL code in socketmodule.c to support
+ RAND_status() and the EGD, and the subsequent patch that tried to
+ fix it for pre-0.9.5 versions; the problem with the patch is that on
+ some systems it issues a warning whenever socket is imported, and
+ that's unacceptable.
+
+Tests
+
+- Fixed the pickle tests to work with "import test.test_pickle".
+
+- Tweaked test_locale.py to actually run the test Windows.
+
+- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
+ not "wb" (which is not a valid mode at all).
+
+- Fix pstats browser crashes. Import readline if it exists to make
+ the user interface nicer.
+
+- Add "import thread" to the top of test modules that import the
+ threading module (test_asynchat and test_threadedtempfile). This
+ prevents test failures caused by a broken threading module resulting
+ from a previously caught failed import.
+
+- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
+ needed on some platforms (e.g. Solaris 8) when the tests are run
+ twice in succession.
+
+- Skip rather than fail test_sunaudiodev if no audio device is found.
+
+
+What's New in Python 2.1c1?
+===========================
+
+This list was significantly updated when 2.1c2 was released; the 2.1c1
+release didn't mention most changes that were actually part of 2.1c1:
+
+Legal
+
+- Copyright was assigned to the Python Software Foundation (PSF) and a
+ PSF license (very similar to the CNRI license) was added.
+
+- The CNRI copyright notice was updated to include 2001.
+
+Core
+
+- After a public outcry, assignment to __debug__ is no longer illegal;
+ instead, a warning is issued. It will become illegal in 2.2.
+
+- Fixed a core dump with "%#x" % 0, and changed the semantics so that
+ "%#x" now always prepends "0x", even if the value is zero.
+
+- Fixed some nits in the bytecode compiler.
+
+- Fixed core dumps when calling certain kinds of non-functions.
+
+- Fixed various core dumps caused by reference count bugs.
+
+Build and Ports
+
+- Use INSTALL_SCRIPT to install script files.
+
+- New port: SCO Unixware 7, by Billy G. Allie.
+
+- Updated RISCOS port.
+
+- Updated BeOS port and notes.
+
+- Various other porting problems resolved.
+
+Library
+
+- The TERMIOS and SOCKET modules are now truly obsolete and
+ unnecessary. Their symbols are incorporated in the termios and
+ socket modules.
+
+- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
+ better tests for pickling.
+
+- threading: make Condition.wait() robust against KeyboardInterrupt.
+
+- zipfile: add support to zipfile to support opening an archive
+ represented by an open file rather than a file name. Fix bug where
+ the archive was not properly closed. Fixed a bug in this bugfix
+ where flush() was called for a read-only file.
+
+- imputil: added an uninstall() method to the ImportManager.
+
+- Canvas: fixed bugs in lower() and tkraise() methods.
+
+- SocketServer: API change (added overridable close_request() method)
+ so that the TCP server can explicitly close the request.
+
+- pstats: Eric Raymond added a simple interactive statistics browser,
+ invoked when the module is run as a script.
+
+- locale: fixed a problem in format().
+
+- webbrowser: made it work when the BROWSER environment variable has a
+ value like "/usr/bin/netscape". Made it auto-detect Konqueror for
+ KDE 2. Fixed some other nits.
+
+- unittest: changes to allow using a different exception than
+ AssertionError, and added a few more function aliases. Some other
+ small changes.
+
+- urllib, urllib2: fixed redirect problems and a coupleof other nits.
+
+- asynchat: fixed a critical bug in asynchat that slipped through the
+ 2.1b2 release. Fixed another rare bug.
+
+- Fix some unqualified except: clauses (always a bad code example).
+
+XML
+
+- pyexpat: new API get_version_string().
+
+- Fixed some minidom bugs.
+
+Extensions
+
+- Fixed a core dump in _weakref. Removed the weakref.mapping()
+ function (it adds nothing to the API).
+
+- Rationalized the use of header files in the readline module, to make
+ it compile (albeit with some warnings) with the very recent readline
+ 4.2, without breaking for earlier versions.
+
+- Hopefully fixed a buffering problem in linuxaudiodev.
+
+- Attempted a fix to make the OpenSSL support in the socket module
+ work again with pre-0.9.5 versions of OpenSSL.
+
+Tests
+
+- Added a test case for asynchat and asyncore.
+
+- Removed coupling between tests where one test failing could break
+ another.
+
+Tools
+
+- Ping added an interactive help browser to pydoc, fixed some nits
+ in the rest of the pydoc code, and added some features to his
+ inspect module.
+
+- An updated python-mode.el version 4.1 which integrates Ken
+ Manheimer's pdbtrack.el. This makes debugging Python code via pdb
+ much nicer in XEmacs and Emacs. When stepping through your program
+ with pdb, in either the shell window or the *Python* window, the
+ source file and line will be tracked by an arrow. Very cool!
+
+- IDLE: syntax warnings in interactive mode are changed into errors.
+
+- Some improvements to Tools/webchecker (ignore some more URL types,
+ follow some more links).
+
+- Brought the Tools/compiler package up to date.
+
+
+What's New in Python 2.1 beta 2?
+================================
+
+(Unlisted are many fixed bugs, more documentation, etc.)
+
+Core language, builtins, and interpreter
+
+- The nested scopes work (enabled by "from __future__ import
+ nested_scopes") is completed; in particular, the future now extends
+ into code executed through exec, eval() and execfile(), and into the
+ interactive interpreter.
+
+- When calling a base class method (e.g. BaseClass.__init__(self)),
+ this is now allowed even if self is not strictly spoken a class
+ instance (e.g. when using metaclasses or the Don Beaudry hook).
+
+- Slice objects are now comparable but not hashable; this prevents
+ dict[:] from being accepted but meaningless.
+
+- Complex division is now calculated using less braindead algorithms.
+ This doesn't change semantics except it's more likely to give useful
+ results in extreme cases. Complex repr() now uses full precision
+ like float repr().
+
+- sgmllib.py now calls handle_decl() for simple <!...> declarations.
+
+- It is illegal to assign to the name __debug__, which is set when the
+ interpreter starts. It is effectively a compile-time constant.
+
+- A warning will be issued if a global statement for a variable
+ follows a use or assignment of that variable.
+
+Standard library
+
+- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
+ inspired by JUnit), is now part of the standard library. You now
+ have a choice of two testing frameworks: unittest requires you to
+ write testcases as separate code, doctest gathers them from
+ docstrings. Both approaches have their advantages and
+ disadvantages.
+
+- A new module Tix was added, which wraps the Tix extension library
+ for Tk. With that module, it is not necessary to statically link
+ Tix with _tkinter, since Tix will be loaded with Tcl's "package
+ require" command. See Demo/tix/.
+
+- tzparse.py is now obsolete.
+
+- In gzip.py, the seek() and tell() methods are removed -- they were
+ non-functional anyway, and it's better if callers can test for their
+ existence with hasattr().
+
+Python/C API
+
+- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
+ that's already in the dictionary during a PyDict_Next() iteration.
+ This used to fail occasionally when a dictionary resize operation
+ could be triggered that would rehash all the keys. All other
+ modifications to the dictionary are still off-limits during a
+ PyDict_Next() iteration!
+
+- New extended APIs related to passing compiler variables around.
+
+- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
+ implement isinstance() and issubclass().
+
+- Py_BuildValue() now has a "D" conversion to create a Python complex
+ number from a Py_complex C value.
+
+- Extensions types which support weak references must now set the
+ field allocated for the weak reference machinery to NULL themselves;
+ this is done to avoid the cost of checking each object for having a
+ weakly referencable type in PyObject_INIT(), since most types are
+ not weakly referencable.
+
+- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
+ free variables and cell variables to and from the frame's f_locals.
+
+- Variants of several functions defined in pythonrun.h have been added
+ to support the nested_scopes future statement. The variants all end
+ in Flags and take an extra argument, a PyCompilerFlags *; examples:
+ PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
+ variants may be removed in Python 2.2, when nested scopes are
+ mandatory.
+
+Distutils
+
+- the sdist command now writes a PKG-INFO file, as described in PEP 241,
+ into the release tree.
+
+- several enhancements to the bdist_wininst command from Thomas Heller
+ (an uninstaller, more customization of the installer's display)
+
+- from Jack Jansen: added Mac-specific code to generate a dialog for
+ users to specify the command-line (because providing a command-line with
+ MacPython is awkward). Jack also made various fixes for the Mac
+ and the Metrowerks compiler.
+
+- added 'platforms' and 'keywords' to the set of metadata that can be
+ specified for a distribution.
+
+- applied patches from Jason Tishler to make the compiler class work with
+ Cygwin.
+
+
+What's New in Python 2.1 beta 1?
+================================
+
+Core language, builtins, and interpreter
+
+- Following an outcry from the community about the amount of code
+ broken by the nested scopes feature introduced in 2.1a2, we decided
+ to make this feature optional, and to wait until Python 2.2 (or at
+ least 6 months) to make it standard. The option can be enabled on a
+ per-module basis by adding "from __future__ import nested_scopes" at
+ the beginning of a module (before any other statements, but after
+ comments and an optional docstring). See PEP 236 (Back to the
+ __future__) for a description of the __future__ statement. PEP 227
+ (Statically Nested Scopes) has been updated to reflect this change,
+ and to clarify the semantics in a number of endcases.
+
+- The nested scopes code, when enabled, has been hardened, and most
+ bugs and memory leaks in it have been fixed.
+
+- Compile-time warnings are now generated for a number of conditions
+ that will break or change in meaning when nested scopes are enabled:
+
+ - Using "from...import *" or "exec" without in-clause in a function
+ scope that also defines a lambda or nested function with one or
+ more free (non-local) variables. The presence of the import* or
+ bare exec makes it impossible for the compiler to determine the
+ exact set of local variables in the outer scope, which makes it
+ impossible to determine the bindings for free variables in the
+ inner scope. To avoid the warning about import *, change it into
+ an import of explicitly name object, or move the import* statement
+ to the global scope; to avoid the warning about bare exec, use
+ exec...in... (a good idea anyway -- there's a possibility that
+ bare exec will be deprecated in the future).
+
+ - Use of a global variable in a nested scope with the same name as a
+ local variable in a surrounding scope. This will change in
+ meaning with nested scopes: the name in the inner scope will
+ reference the variable in the outer scope rather than the global
+ of the same name. To avoid the warning, either rename the outer
+ variable, or use a global statement in the inner function.
+
+- An optional object allocator has been included. This allocator is
+ optimized for Python objects and should be faster and use less memory
+ than the standard system allocator. It is not enabled by default
+ because of possible thread safety problems. The allocator is only
+ protected by the Python interpreter lock and it is possible that some
+ extension modules require a thread safe allocator. The object
+ allocator can be enabled by providing the "--with-pymalloc" option to
+ configure.
+
+Standard library
+
+- pyexpat now detects the expat version if expat.h defines it. A
+ number of additional handlers are provided, which are only available
+ since expat 1.95. In addition, the methods SetParamEntityParsing and
+ GetInputContext of Parser objects are available with 1.95.x
+ only. Parser objects now provide the ordered_attributes and
+ specified_attributes attributes. A new module expat.model was added,
+ which offers a number of additional constants if 1.95.x is used.
+
+- xml.dom offers the new functions registerDOMImplementation and
+ getDOMImplementation.
+
+- xml.dom.minidom offers a toprettyxml method. A number of DOM
+ conformance issues have been resolved. In particular, Element now
+ has an hasAttributes method, and the handling of namespaces was
+ improved.
+
+- Ka-Ping Yee contributed two new modules: inspect.py, a module for
+ getting information about live Python code, and pydoc.py, a module
+ for interactively converting docstrings to HTML or text.
+ Tools/scripts/pydoc, which is now automatically installed into
+ <prefix>/bin, uses pydoc.py to display documentation; try running
+ "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
+ lets you browse the module docstrings using a web browser.
+
+- New library module difflib.py, primarily packaging the SequenceMatcher
+ class at the heart of the popular ndiff.py file-comparison tool.
+
+- doctest.py (a framework for verifying Python code examples in docstrings)
+ is now part of the std library.
+
+Windows changes
+
+- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
+ small GUI that lets you browse the module docstrings using your
+ default web browser.
+
+- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
+ Platforms) is implemented. See
+
+ http://python.sourceforge.net/peps/pep-0235.html
+
+ for full details, especially the "Current Lower-Left Semantics" section.
+ The new Windows import rules are simpler than before:
+
+ A. If the PYTHONCASEOK environment variable exists, same as
+ before: silently accept the first case-insensitive match of any
+ kind; raise ImportError if none found.
+
+ B. Else search sys.path for the first case-sensitive match; raise
+ ImportError if none found.
+
+ The same rules have been implemented on other platforms with case-
+ insensitive but case-preserving filesystems too (including Cygwin, and
+ several flavors of Macintosh operating systems).
+
+- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
+ what it's supposed to do (and does do under NT and 2000) via direct
+ port manipulation. It's unknown whether this will work on all systems,
+ but it does work on my Win98SE systems now and was known to be useless on
+ all Win9x systems before.
+
+- Build: Subproject _test (effectively) renamed to _testcapi.
+
+New platforms
+
+- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
+ Thanks to Steven Majewski!
+
+- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
+ Tishler!
+
+- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
+ Schwertberger! See RISCOS/README for more information -- it seems
+ that because of the bizarre filename conventions on RISCOS, no port
+ to that platform is easy.
+
+
+What's New in Python 2.1 alpha 2?
+=================================
+
+Core language, builtins, and interpreter
+
+- Scopes nest. If a name is used in a function or class, but is not
+ local, the definition in the nearest enclosing function scope will
+ be used. One consequence of this change is that lambda statements
+ could reference variables in the namespaces where the lambda is
+ defined. In some unusual cases, this change will break code.
+
+ In all previous version of Python, names were resolved in exactly
+ three namespaces -- the local namespace, the global namespace, and
+ the builtin namespace. According to this old definition, if a
+ function A is defined within a function B, the names bound in B are
+ not visible in A. The new rules make names bound in B visible in A,
+ unless A contains a name binding that hides the binding in B.
+
+ Section 4.1 of the reference manual describes the new scoping rules
+ in detail. The test script in Lib/test/test_scope.py demonstrates
+ some of the effects of the change.
+
+ The new rules will cause existing code to break if it defines nested
+ functions where an outer function has local variables with the same
+ name as globals or builtins used by the inner function. Example:
+
+ def munge(str):
+ def helper(x):
+ return str(x)
+ if type(str) != type(''):
+ str = helper(str)
+ return str.strip()
+
+ Under the old rules, the name str in helper() is bound to the
+ builtin function str(). Under the new rules, it will be bound to
+ the argument named str and an error will occur when helper() is
+ called.
+
+- The compiler will report a SyntaxError if "from ... import *" occurs
+ in a function or class scope. The language reference has documented
+ that this case is illegal, but the compiler never checked for it.
+ The recent introduction of nested scope makes the meaning of this
+ form of name binding ambiguous. In a future release, the compiler
+ may allow this form when there is no possibility of ambiguity.
+
+- repr(string) is easier to read, now using hex escapes instead of octal,
+ and using \t, \n and \r instead of \011, \012 and \015 (respectively):
+
+ >>> "\texample \r\n" + chr(0) + chr(255)
+ '\texample \r\n\x00\xff' # in 2.1
+ '\011example \015\012\000\377' # in 2.0
+
+- Functions are now compared and hashed by identity, not by value, since
+ the func_code attribute is writable.
+
+- Weak references (PEP 205) have been added. This involves a few
+ changes in the core, an extension module (_weakref), and a Python
+ module (weakref). The weakref module is the public interface. It
+ includes support for "explicit" weak references, proxy objects, and
+ mappings with weakly held values.
+
+- A 'continue' statement can now appear in a try block within the body
+ of a loop. It is still not possible to use continue in a finally
+ clause.
+
+Standard library
+
+- mailbox.py now has a new class, PortableUnixMailbox which is
+ identical to UnixMailbox but uses a more portable scheme for
+ determining From_ separators. Also, the constructors for all the
+ classes in this module have a new optional `factory' argument, which
+ is a callable used when new message classes must be instantiated by
+ the next() method.
+
+- random.py is now self-contained, and offers all the functionality of
+ the now-deprecated whrandom.py. See the docs for details. random.py
+ also supports new functions getstate() and setstate(), for saving
+ and restoring the internal state of the generator; and jumpahead(n),
+ for quickly forcing the internal state to be the same as if n calls to
+ random() had been made. The latter is particularly useful for multi-
+ threaded programs, creating one instance of the random.Random() class for
+ each thread, then using .jumpahead() to force each instance to use a
+ non-overlapping segment of the full period.
+
+- random.py's seed() function is new. For bit-for-bit compatibility with
+ prior releases, use the whseed function instead. The new seed function
+ addresses two problems: (1) The old function couldn't produce more than
+ about 2**24 distinct internal states; the new one about 2**45 (the best
+ that can be done in the Wichmann-Hill generator). (2) The old function
+ sometimes produced identical internal states when passed distinct
+ integers, and there was no simple way to predict when that would happen;
+ the new one guarantees to produce distinct internal states for all
+ arguments in [0, 27814431486576L).
+
+- The socket module now supports raw packets on Linux. The socket
+ family is AF_PACKET.
+
+- test_capi.py is a start at running tests of the Python C API. The tests
+ are implemented by the new Modules/_testmodule.c.
+
+- A new extension module, _symtable, provides provisional access to the
+ internal symbol table used by the Python compiler. A higher-level
+ interface will be added on top of _symtable in a future release.
+
+- Removed the obsolete soundex module.
+
+- xml.dom.minidom now uses the standard DOM exceptions. Node supports
+ the isSameNode method; NamedNodeMap the get method.
+
+- xml.sax.expatreader supports the lexical handler property; it
+ generates comment, startCDATA, and endCDATA events.
+
+Windows changes
+
+- Build procedure: the zlib project is built in a different way that
+ ensures the zlib header files used can no longer get out of synch with
+ the zlib binary used. See PCbuild\readme.txt for details. Your old
+ zlib-related directories can be deleted; you'll need to download fresh
+ source for zlib and unpack it into a new directory.
+
+- Build: New subproject _test for the benefit of test_capi.py (see above).
+
+- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
+ interface to some Python compiler internals).
+
+- Build: Subproject ucnhash is gone, since the code was folded into the
+ unicodedata subproject.
+
+What's New in Python 2.1 alpha 1?
+=================================
+
+Core language, builtins, and interpreter
+
+- There is a new Unicode companion to the PyObject_Str() API
+ called PyObject_Unicode(). It behaves in the same way as the
+ former, but assures that the returned value is an Unicode object
+ (applying the usual coercion if necessary).
+
+- The comparison operators support "rich comparison overloading" (PEP
+ 207). C extension types can provide a rich comparison function in
+ the new tp_richcompare slot in the type object. The cmp() function
+ and the C function PyObject_Compare() first try the new rich
+ comparison operators before trying the old 3-way comparison. There
+ is also a new C API PyObject_RichCompare() (which also falls back on
+ the old 3-way comparison, but does not constrain the outcome of the
+ rich comparison to a Boolean result).
+
+ The rich comparison function takes two objects (at least one of
+ which is guaranteed to have the type that provided the function) and
+ an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
+ Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
+ object, which may be NotImplemented (in which case the tp_compare
+ slot function is used as a fallback, if defined).
+
+ Classes can overload individual comparison operators by defining one
+ or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
+ __ge__. There are no explicit "reflected argument" versions of
+ these; instead, __lt__ and __gt__ are each other's reflection,
+ likewise for__le__ and __ge__; __eq__ and __ne__ are their own
+ reflection (similar at the C level). No other implications are
+ made; in particular, Python does not assume that == is the Boolean
+ inverse of !=, or that < is the Boolean inverse of >=. This makes
+ it possible to define types with partial orderings.
+
+ Classes or types that want to implement (in)equality tests but not
+ the ordering operators (i.e. unordered types) should implement ==
+ and !=, and raise an error for the ordering operators.
+
+ It is possible to define types whose rich comparison results are not
+ Boolean; e.g. a matrix type might want to return a matrix of bits
+ for A < B, giving elementwise comparisons. Such types should ensure
+ that any interpretation of their value in a Boolean context raises
+ an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
+ at the C level) to always raise an exception.
+
+- Complex numbers use rich comparisons to define == and != but raise
+ an exception for <, <=, > and >=. Unfortunately, this also means
+ that cmp() of two complex numbers raises an exception when the two
+ numbers differ. Since it is not mathematically meaningful to compare
+ complex numbers except for equality, I hope that this doesn't break
+ too much code.
+
+- The outcome of comparing non-numeric objects of different types is
+ not defined by the language, other than that it's arbitrary but
+ consistent (see the Reference Manual). An implementation detail changed
+ in 2.1a1 such that None now compares less than any other object. Code
+ relying on this new behavior (like code that relied on the previous
+ behavior) does so at its own risk.
+
+- Functions and methods now support getting and setting arbitrarily
+ named attributes (PEP 232). Functions have a new __dict__
+ (a.k.a. func_dict) which hold the function attributes. Methods get
+ and set attributes on their underlying im_func. It is a TypeError
+ to set an attribute on a bound method.
+
+- The xrange() object implementation has been improved so that
+ xrange(sys.maxint) can be used on 64-bit platforms. There's still a
+ limitation that in this case len(xrange(sys.maxint)) can't be
+ calculated, but the common idiom "for i in xrange(sys.maxint)" will
+ work fine as long as the index i doesn't actually reach 2**31.
+ (Python uses regular ints for sequence and string indices; fixing
+ that is much more work.)
+
+- Two changes to from...import:
+
+ 1) "from M import X" now works even if (after loading module M)
+ sys.modules['M'] is not a real module; it's basically a getattr()
+ operation with AttributeError exceptions changed into ImportError.
+
+ 2) "from M import *" now looks for M.__all__ to decide which names to
+ import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
+ filters out names starting with '_' as before. Whether or not
+ __all__ exists, there's no restriction on the type of M.
+
+- File objects have a new method, xreadlines(). This is the fastest
+ way to iterate over all lines in a file:
+
+ for line in file.xreadlines():
+ ...do something to line...
+
+ See the xreadlines module (mentioned below) for how to do this for
+ other file-like objects.
+
+- Even if you don't use file.xreadlines(), you may expect a speedup on
+ line-by-line input. The file.readline() method has been optimized
+ quite a bit in platform-specific ways: on systems (like Linux) that
+ support flockfile(), getc_unlocked(), and funlockfile(), those are
+ used by default. On systems (like Windows) without getc_unlocked(),
+ a complicated (but still thread-safe) method using fgets() is used by
+ default.
+
+ You can force use of the fgets() method by #define'ing
+ USE_FGETS_IN_GETLINE at build time (it may be faster than
+ getc_unlocked()).
+
+ You can force fgets() not to be used by #define'ing
+ DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
+ test_bufio.py fails -- and let us know if it does!).
+
+- In addition, the fileinput module, while still slower than the other
+ methods on most platforms, has been sped up too, by using
+ file.readlines(sizehint).
+
+- Support for run-time warnings has been added, including a new
+ command line option (-W) to specify the disposition of warnings.
+ See the description of the warnings module below.
+
+- Extensive changes have been made to the coercion code. This mostly
+ affects extension modules (which can now implement mixed-type
+ numerical operators without having to use coercion), but
+ occasionally, in boundary cases the coercion semantics have changed
+ subtly. Since this was a terrible gray area of the language, this
+ is considered an improvement. Also note that __rcmp__ is no longer
+ supported -- instead of calling __rcmp__, __cmp__ is called with
+ reflected arguments.
+
+- In connection with the coercion changes, a new built-in singleton
+ object, NotImplemented is defined. This can be returned for
+ operations that wish to indicate they are not implemented for a
+ particular combination of arguments. From C, this is
+ Py_NotImplemented.
+
+- The interpreter accepts now bytecode files on the command line even
+ if they do not have a .pyc or .pyo extension. On Linux, after executing
+
+import imp,sys,string
+magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
+reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
+open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
+
+ any byte code file can be used as an executable (i.e. as an argument
+ to execve(2)).
+
+- %[xXo] formats of negative Python longs now produce a sign
+ character. In 1.6 and earlier, they never produced a sign,
+ and raised an error if the value of the long was too large
+ to fit in a Python int. In 2.0, they produced a sign if and
+ only if too large to fit in an int. This was inconsistent
+ across platforms (because the size of an int varies across
+ platforms), and inconsistent with hex() and oct(). Example:
+
+ >>> "%x" % -0x42L
+ '-42' # in 2.1
+ 'ffffffbe' # in 2.0 and before, on 32-bit machines
+ >>> hex(-0x42L)
+ '-0x42L' # in all versions of Python
+
+ The behavior of %d formats for negative Python longs remains
+ the same as in 2.0 (although in 1.6 and before, they raised
+ an error if the long didn't fit in a Python int).
+
+ %u formats don't make sense for Python longs, but are allowed
+ and treated the same as %d in 2.1. In 2.0, a negative long
+ formatted via %u produced a sign if and only if too large to
+ fit in an int. In 1.6 and earlier, a negative long formatted
+ via %u raised an error if it was too big to fit in an int.
+
+- Dictionary objects have an odd new method, popitem(). This removes
+ an arbitrary item from the dictionary and returns it (in the form of
+ a (key, value) pair). This can be useful for algorithms that use a
+ dictionary as a bag of "to do" items and repeatedly need to pick one
+ item. Such algorithms normally end up running in quadratic time;
+ using popitem() they can usually be made to run in linear time.
+
+Standard library
+
+- In the time module, the time argument to the functions strftime,
+ localtime, gmtime, asctime and ctime is now optional, defaulting to
+ the current time (in the local timezone).
+
+- The ftplib module now defaults to passive mode, which is deemed a
+ more useful default given that clients are often inside firewalls
+ these days. Note that this could break if ftplib is used to connect
+ to a *server* that is inside a firewall, from outside; this is
+ expected to be a very rare situation. To fix that, you can call
+ ftp.set_pasv(0).
+
+- The module site now treats .pth files not only for path configuration,
+ but also supports extensions to the initialization code: Lines starting
+ with import are executed.
+
+- There's a new module, warnings, which implements a mechanism for
+ issuing and filtering warnings. There are some new built-in
+ exceptions that serve as warning categories, and a new command line
+ option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
+ turns warnings into errors). warnings.warn(message[, category])
+ issues a warning message; this can also be called from C as
+ PyErr_Warn(category, message).
+
+- A new module xreadlines was added. This exports a single factory
+ function, xreadlines(). The intention is that this code is the
+ absolutely fastest way to iterate over all lines in an open
+ file(-like) object:
+
+ import xreadlines
+ for line in xreadlines.xreadlines(file):
+ ...do something to line...
+
+ This is equivalent to the previous the speed record holder using
+ file.readlines(sizehint). Note that if file is a real file object
+ (as opposed to a file-like object), this is equivalent:
+
+ for line in file.xreadlines():
+ ...do something to line...
+
+- The bisect module has new functions bisect_left, insort_left,
+ bisect_right and insort_right. The old names bisect and insort
+ are now aliases for bisect_right and insort_right. XXX_right
+ and XXX_left methods differ in what happens when the new element
+ compares equal to one or more elements already in the list: the
+ XXX_left methods insert to the left, the XXX_right methods to the
+ right. Code that doesn't care where equal elements end up should
+ continue to use the old, short names ("bisect" and "insort").
+
+- The new curses.panel module wraps the panel library that forms part
+ of SYSV curses and ncurses. Contributed by Thomas Gellekum.
+
+- The SocketServer module now sets the allow_reuse_address flag by
+ default in the TCPServer class.
+
+- A new function, sys._getframe(), returns the stack frame pointer of
+ the caller. This is intended only as a building block for
+ higher-level mechanisms such as string interpolation.
+
+- The pyexpat module supports a number of new handlers, which are
+ available only in expat 1.2. If invocation of a callback fails, it
+ will report an additional frame in the traceback. Parser objects
+ participate now in garbage collection. If expat reports an unknown
+ encoding, pyexpat will try to use a Python codec; that works only
+ for single-byte charsets. The parser type objects is exposed as
+ XMLParserObject.
+
+- xml.dom now offers standard definitions for symbolic node type and
+ exception code constants, and a hierarchy of DOM exceptions. minidom
+ was adjusted to use them.
+
+- The conformance of xml.dom.minidom to the DOM specification was
+ improved. It detects a number of additional error cases; the
+ previous/next relationship works even when the tree is modified;
+ Node supports the normalize() method; NamedNodeMap, DocumentType and
+ DOMImplementation classes were added; Element supports the
+ hasAttribute and hasAttributeNS methods; and Text supports the splitText
+ method.
+
+Build issues
+
+- For Unix (and Unix-compatible) builds, configuration and building of
+ extension modules is now greatly automated. Rather than having to
+ edit the Modules/Setup file to indicate which modules should be
+ built and where their include files and libraries are, a
+ distutils-based setup.py script now takes care of building most
+ extension modules. All extension modules built this way are built
+ as shared libraries. Only a few modules that must be linked
+ statically are still listed in the Setup file; you won't need to
+ edit their configuration.
+
+- Python should now build out of the box on Cygwin. If it doesn't,
+ mail to Jason Tishler (jlt63 at users.sourceforge.net).
+
+- Python now always uses its own (renamed) implementation of getopt()
+ -- there's too much variation among C library getopt()
+ implementations.
+
+- C++ compilers are better supported; the CXX macro is always set to a
+ C++ compiler if one is found.
+
+Windows changes
+
+- select module: By default under Windows, a select() call
+ can specify no more than 64 sockets. Python now boosts
+ this Microsoft default to 512. If you need even more than
+ that, see the MS docs (you'll need to #define FD_SETSIZE
+ and recompile Python from source).
+
+- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
+ subdirectory is no more!
+
+
+What's New in Python 2.0?
+=========================
+
+Below is a list of all relevant changes since release 1.6. Older
+changes are in the file HISTORY. If you are making the jump directly
+from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
+HISTORY file! Many important changes listed there.
+
+Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
+the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
+http://starship.python.net/crew/amk/python/writing/new-python/.
+
+--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
+
+======================================================================
+
+What's new in 2.0 (since release candidate 1)?
+==============================================
+
+Standard library
+
+- The copy_reg module was modified to clarify its intended use: to
+ register pickle support for extension types, not for classes.
+ pickle() will raise a TypeError if it is passed a class.
+
+- Fixed a bug in gettext's "normalize and expand" code that prevented
+ it from finding an existing .mo file.
+
+- Restored support for HTTP/0.9 servers in httplib.
+
+- The math module was changed to stop raising OverflowError in case of
+ underflow, and return 0 instead in underflow cases. Whether Python
+ used to raise OverflowError in case of underflow was platform-
+ dependent (it did when the platform math library set errno to ERANGE
+ on underflow).
+
+- Fixed a bug in StringIO that occurred when the file position was not
+ at the end of the file and write() was called with enough data to
+ extend past the end of the file.
+
+- Fixed a bug that caused Tkinter error messages to get lost on
+ Windows. The bug was fixed by replacing direct use of
+ interp->result with Tcl_GetStringResult(interp).
+
+- Fixed bug in urllib2 that caused it to fail when it received an HTTP
+ redirect response.
+
+- Several changes were made to distutils: Some debugging code was
+ removed from util. Fixed the installer used when an external zip
+ program (like WinZip) is not found; the source code for this
+ installer is in Misc/distutils. check_lib() was modified to behave
+ more like AC_CHECK_LIB by add other_libraries() as a parameter. The
+ test for whether installed modules are on sys.path was changed to
+ use both normcase() and normpath().
+
+- Several minor bugs were fixed in the xml package (the minidom,
+ pulldom, expatreader, and saxutils modules).
+
+- The regression test driver (regrtest.py) behavior when invoked with
+ -l changed: It now reports a count of objects that are recognized as
+ garbage but not freed by the garbage collector.
+
+- The regression test for the math module was changed to test
+ exceptional behavior when the test is run in verbose mode. Python
+ cannot yet guarantee consistent exception behavior across platforms,
+ so the exception part of test_math is run only in verbose mode, and
+ may fail on your platform.
+
+Internals
+
+- PyOS_CheckStack() has been disabled on Win64, where it caused
+ test_sre to fail.
+
+Build issues
+
+- Changed compiler flags, so that gcc is always invoked with -Wall and
+ -Wstrict-prototypes. Users compiling Python with GCC should see
+ exactly one warning, except if they have passed configure the
+ --with-pydebug flag. The expected warning is for getopt() in
+ Modules/main.c. This warning will be fixed for Python 2.1.
+
+- Fixed configure to add -threads argument during linking on OSF1.
+
+Tools and other miscellany
+
+- The compiler in Tools/compiler was updated to support the new
+ language features introduced in 2.0: extended print statement, list
+ comprehensions, and augmented assignments. The new compiler should
+ also be backwards compatible with Python 1.5.2; the compiler will
+ always generate code for the version of the interpreter it runs
+ under.
+
+What's new in 2.0 release candidate 1 (since beta 2)?
+=====================================================
+
+What is release candidate 1?
+
+We believe that release candidate 1 will fix all known bugs that we
+intend to fix for the 2.0 final release. This release should be a bit
+more stable than the previous betas. We would like to see even more
+widespread testing before the final release, so we are producing this
+release candidate. The final release will be exactly the same unless
+any show-stopping (or brown bag) bugs are found by testers of the
+release candidate.
+
+All the changes since the last beta release are bug fixes or changes
+to support building Python for specific platforms.
+
+Core language, builtins, and interpreter
+
+- A bug that caused crashes when __coerce__ was used with augmented
+ assignment, e.g. +=, was fixed.
+
+- Raise ZeroDivisionError when raising zero to a negative number,
+ e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
+ power operator and the result of math.pow(0.0, -2.0) will vary by
+ platform. On Linux, it raises a ValueError.
+
+- A bug in Unicode string interpolation was fixed that occasionally
+ caused errors with formats including "%%". For example, the
+ following expression "%% %s" % u"abc" no longer raises a TypeError.
+
+- Compilation of deeply nested expressions raises MemoryError instead
+ of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
+
+- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
+ rendering them useless. They are now written in binary mode again.
+
+Standard library
+
+- Keyword arguments are now accepted for most pattern and match object
+ methods in SRE, the standard regular expression engine.
+
+- In SRE, fixed error with negative lookahead and lookbehind that
+ manifested itself as a runtime error in patterns like "(?<!abc)(def)".
+
+- Several bugs in the Unicode handling and error handling in _tkinter
+ were fixed.
+
+- Fix memory management errors in Merge() and Tkapp_Call() routines.
+
+- Several changes were made to cStringIO to make it compatible with
+ the file-like object interface and with StringIO. If operations are
+ performed on a closed object, an exception is raised. The truncate
+ method now accepts a position argument and readline accepts a size
+ argument.
+
+- There were many changes made to the linuxaudiodev module and its
+ test suite; as a result, a short, unexpected audio sample should now
+ play when the regression test is run.
+
+ Note that this module is named poorly, because it should work
+ correctly on any platform that supports the Open Sound System
+ (OSS).
+
+ The module now raises exceptions when errors occur instead of
+ crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
+ audio) and defines a getptr() method that calls the
+ SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
+
+- The library_version attribute, introduced in an earlier beta, was
+ removed because it can not be supported with early versions of the C
+ readline library, which provides no way to determine the version at
+ compile-time.
+
+- The binascii module is now enabled on Win64.
+
+- tokenize.py no longer suffers "recursion depth" errors when parsing
+ programs with very long string literals.
+
+Internals
+
+- Fixed several buffer overflow vulnerabilities in calculate_path(),
+ which is called when the interpreter starts up to determine where
+ the standard library is installed. These vulnerabilities affect all
+ previous versions of Python and can be exploited by setting very
+ long values for PYTHONHOME or argv[0]. The risk is greatest for a
+ setuid Python script, although use of the wrapper in
+ Misc/setuid-prog.c will eliminate the vulnerability.
+
+- Fixed garbage collection bugs in instance creation that were
+ triggered when errors occurred during initialization. The solution,
+ applied in cPickle and in PyInstance_New(), is to call
+ PyObject_GC_Init() after the initialization of the object's
+ container attributes is complete.
+
+- pyexpat adds definitions of PyModule_AddStringConstant and
+ PyModule_AddObject if the Python version is less than 2.0, which
+ provides compatibility with PyXML on Python 1.5.2.
+
+- If the platform has a bogus definition for LONG_BIT (the number of
+ bits in a long), an error will be reported at compile time.
+
+- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
+ collection crashes and possibly other, unreported crashes.
+
+- Fixed a memory leak in _PyUnicode_Fini().
+
+Build issues
+
+- configure now accepts a --with-suffix option that specifies the
+ executable suffix. This is useful for builds on Cygwin and Mac OS
+ X, for example.
+
+- The mmap.PAGESIZE constant is now initialized using sysconf when
+ possible, which eliminates a dependency on -lucb for Reliant UNIX.
+
+- The md5 file should now compile on all platforms.
+
+- The select module now compiles on platforms that do not define
+ POLLRDNORM and related constants.
+
+- Darwin (Mac OS X): Initial support for static builds on this
+ platform.
+
+- BeOS: A number of changes were made to the build and installation
+ process. ar-fake now operates on a directory of object files.
+ dl_export.h is gone, and its macros now appear on the mwcc command
+ line during build on PPC BeOS.
+
+- Platform directory in lib/python2.0 is "plat-beos5" (or
+ "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
+
+- Cygwin: Support for shared libraries, Tkinter, and sockets.
+
+- SunOS 4.1.4_JL: Fix test for directory existence in configure.
+
+Tools and other miscellany
+
+- Removed debugging prints from main used with freeze.
+
+- IDLE auto-indent no longer crashes when it encounters Unicode
+ characters.
+
+What's new in 2.0 beta 2 (since beta 1)?
+========================================
+
+Core language, builtins, and interpreter
+
+- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
+ "%d" % 2L**64 == "18446744073709551616".
+
+- Add -h and -V command line options to print the usage message and
+ Python version number and exit immediately.
+
+- eval() and exec accept Unicode objects as code parameters.
+
+- getattr() and setattr() now also accept Unicode objects for the
+ attribute name, which are converted to strings using the default
+ encoding before lookup.
+
+- Multiplication on string and Unicode now does proper bounds
+ checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
+ string is too long."
+
+- Better error message when continue is found in try statement in a
+ loop.
+
+
+Standard library and extensions
+
+- socket module: the OpenSSL code now adds support for RAND_status()
+ and EGD (Entropy Gathering Device).
+
+- array: reverse() method of array now works. buffer_info() now does
+ argument checking; it still takes no arguments.
+
+- asyncore/asynchat: Included most recent version from Sam Rushing.
+
+- cgi: Accept '&' or ';' as separator characters when parsing form data.
+
+- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
+
+- ConfigParser: When reading the file, options spelled in upper case
+ letters are now correctly converted to lowercase.
+
+- copy: Copy Unicode objects atomically.
+
+- cPickle: Fail gracefully when copy_reg can't be imported.
+
+- cStringIO: Implemented readlines() method.
+
+- dbm: Add get() and setdefault() methods to dbm object. Add constant
+ `library' to module that names the library used. Added doc strings
+ and method names to error messages. Uses configure to determine
+ which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
+ now available options.
+
+- distutils: Update to version 0.9.3.
+
+- dl: Add several dl.RTLD_ constants.
+
+- fpectl: Now supported on FreeBSD.
+
+- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
+ found by the collector will be saved in gc.garbage. This is useful
+ for debugging a program that creates reference cycles.
+
+- httplib: Three changes: Restore support for set_debuglevel feature
+ of HTTP class. Do not close socket on zero-length response. Do not
+ crash when server sends invalid content-length header.
+
+- mailbox: Mailbox class conforms better to qmail specifications.
+
+- marshal: When reading a short, sign-extend on platforms where shorts
+ are bigger than 16 bits. When reading a long, repair the unportable
+ sign extension that was being done for 64-bit machines. (It assumed
+ that signed right shift sign-extends.)
+
+- operator: Add contains(), invert(), __invert__() as aliases for
+ __contains__(), inv(), and __inv__() respectively.
+
+- os: Add support for popen2() and popen3() on all platforms where
+ fork() exists. (popen4() is still in the works.)
+
+- os: (Windows only:) Add startfile() function that acts like double-
+ clicking on a file in Explorer (or passing the file name to the
+ DOS "start" command).
+
+- os.path: (Windows, DOS:) Treat trailing colon correctly in
+ os.path.join. os.path.join("a:", "b") yields "a:b".
+
+- pickle: Now raises ValueError when an invalid pickle that contains
+ a non-string repr where a string repr was expected. This behavior
+ matches cPickle.
+
+- posixfile: Remove broken __del__() method.
+
+- py_compile: support CR+LF line terminators in source file.
+
+- readline: Does not immediately exit when ^C is hit when readline and
+ threads are configured. Adds definition of rl_library_version. (The
+ latter addition requires GNU readline 2.2 or later.)
+
+- rfc822: Domain literals returned by AddrlistClass method
+ getdomainliteral() are now properly wrapped in brackets.
+
+- site: sys.setdefaultencoding() should only be called in case the
+ standard default encoding ("ascii") is changed. This saves quite a
+ few cycles during startup since the first call to
+ setdefaultencoding() will initialize the codec registry and the
+ encodings package.
+
+- socket: Support for size hint in readlines() method of object returned
+ by makefile().
+
+- sre: Added experimental expand() method to match objects. Does not
+ use buffer interface on Unicode strings. Does not hang if group id
+ is followed by whitespace.
+
+- StringIO: Size hint in readlines() is now supported as documented.
+
+- struct: Check ranges for bytes and shorts.
+
+- urllib: Improved handling of win32 proxy settings. Fixed quote and
+ quote_plus functions so that the always encode a comma.
+
+- Tkinter: Image objects are now guaranteed to have unique ids. Set
+ event.delta to zero if Tk version doesn't support mousewheel.
+ Removed some debugging prints.
+
+- UserList: now implements __contains__().
+
+- webbrowser: On Windows, use os.startfile() instead of os.popen(),
+ which works around a bug in Norton AntiVirus 2000 that leads directly
+ to a Blue Screen freeze.
+
+- xml: New version detection code allows PyXML to override standard
+ XML package if PyXML version is greater than 0.6.1.
+
+- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
+ (conventional DOM), and xml.dom.pulldom, which allows building the DOM
+ tree only for nodes which are sufficiently interesting to a specific
+ application. Does not provide the HTML-specific extensions. Still
+ undocumented.
+
+- xml.sax: SAX 2 support for Python, including all the handler
+ interfaces needed to process XML 1.0 compliant XML. Some
+ documentation is already available.
+
+- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
+ packagized XML support.
+
+
+C API
+
+- Add three new convenience functions for module initialization --
+ PyModule_AddObject(), PyModule_AddIntConstant(), and
+ PyModule_AddStringConstant().
+
+- Cleaned up definition of NULL in C source code; all definitions were
+ removed and add #error to Python.h if NULL isn't defined after
+ #include of stdio.h.
+
+- Py_PROTO() macros that were removed in 2.0b1 have been restored for
+ backwards compatibility (at the source level) with old extensions.
+
+- A wrapper API was added for signal() and sigaction(). Instead of
+ either function, always use PyOS_getsig() to get a signal handler
+ and PyOS_setsig() to set one. A new convenience typedef
+ PyOS_sighandler_t is defined for the type of signal handlers.
+
+- Add PyString_AsStringAndSize() function that provides access to the
+ internal data buffer and size of a string object -- or the default
+ encoded version of a Unicode object.
+
+- PyString_Size() and PyString_AsString() accept Unicode objects.
+
+- The standard header <limits.h> is now included by Python.h (if it
+ exists). INT_MAX and LONG_MAX will always be defined, even if
+ <limits.h> is not available.
+
+- PyFloat_FromString takes a second argument, pend, that was
+ effectively useless. It is now officially useless but preserved for
+ backwards compatibility. If the pend argument is not NULL, *pend is
+ set to NULL.
+
+- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
+ for the attribute name. See note on getattr() above.
+
+- A few bug fixes to argument processing for Unicode.
+ PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
+ PyArg_Parse() special cases "s#" for Unicode objects; it returns a
+ pointer to the default encoded string data instead of to the raw
+ UTF-16.
+
+- Py_BuildValue accepts B format (for bgen-generated code).
+
+
+Internals
+
+- On Unix, fix code for finding Python installation directory so that
+ it works when argv[0] is a relative path.
+
+- Added a true unicode_internal_encode() function and fixed the
+ unicode_internal_decode function() to support Unicode objects directly
+ rather than by generating a copy of the object.
+
+- Several of the internal Unicode tables are much smaller now, and
+ the source code should be much friendlier to weaker compilers.
+
+- In the garbage collector: Fixed bug in collection of tuples. Fixed
+ bug that caused some instances to be removed from the container set
+ while they were still live. Fixed parsing in gc.set_debug() for
+ platforms where sizeof(long) > sizeof(int).
+
+- Fixed refcount problem in instance deallocation that only occurred
+ when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
+
+- On Windows, getpythonregpath is now protected against null data in
+ registry key.
+
+- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
+ condition.
+
+
+Build and platform-specific issues
+
+- Better support of GNU Pth via --with-pth configure option.
+
+- Python/C API now properly exposed to dynamically-loaded extension
+ modules on Reliant UNIX.
+
+- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
+ Don't define MS_SYNC to be zero when it is undefined. Added missing
+ prototypes in posixmodule.c.
+
+- Improved support for HP-UX build. Threads should now be correctly
+ configured (on HP-UX 10.20 and 11.00).
+
+- Fix largefile support on older NetBSD systems and OpenBSD by adding
+ define for TELL64.
+
+
+Tools and other miscellany
+
+- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
+
+- freeze: The modulefinder now works with 2.0 opcodes.
+
+- IDLE:
+ Move hackery of sys.argv until after the Tk instance has been
+ created, which allows the application-specific Tkinter
+ initialization to be executed if present; also pass an explicit
+ className parameter to the Tk() constructor.
+
+
+What's new in 2.0 beta 1?
+=========================
+
+Source Incompatibilities
+------------------------
+
+None. Note that 1.6 introduced several incompatibilities with 1.5.2,
+such as single-argument append(), connect() and bind(), and changes to
+str(long) and repr(float).
+
+
+Binary Incompatibilities
+------------------------
+
+- Third party extensions built for Python 1.5.x or 1.6 cannot be used
+with Python 2.0; these extensions will have to be rebuilt for Python
+2.0.
+
+- On Windows, attempting to import a third party extension built for
+Python 1.5.x or 1.6 results in an immediate crash; there's not much we
+can do about this. Check your PYTHONPATH environment variable!
+
+- Python bytecode files (*.pyc and *.pyo) are not compatible between
+releases.
+
+
+Overview of Changes Since 1.6
+-----------------------------
+
+There are many new modules (including brand new XML support through
+the xml package, and i18n support through the gettext module); a list
+of all new modules is included below. Lots of bugs have been fixed.
+
+The process for making major new changes to the language has changed
+since Python 1.6. Enhancements must now be documented by a Python
+Enhancement Proposal (PEP) before they can be accepted.
+
+There are several important syntax enhancements, described in more
+detail below:
+
+ - Augmented assignment, e.g. x += 1
+
+ - List comprehensions, e.g. [x**2 for x in range(10)]
+
+ - Extended import statement, e.g. import Module as Name
+
+ - Extended print statement, e.g. print >> file, "Hello"
+
+Other important changes:
+
+ - Optional collection of cyclical garbage
+
+Python Enhancement Proposal (PEP)
+---------------------------------
+
+PEP stands for Python Enhancement Proposal. A PEP is a design
+document providing information to the Python community, or describing
+a new feature for Python. The PEP should provide a concise technical
+specification of the feature and a rationale for the feature.
+
+We intend PEPs to be the primary mechanisms for proposing new
+features, for collecting community input on an issue, and for
+documenting the design decisions that have gone into Python. The PEP
+author is responsible for building consensus within the community and
+documenting dissenting opinions.
+
+The PEPs are available at http://python.sourceforge.net/peps/.
+
+Augmented Assignment
+--------------------
+
+This must have been the most-requested feature of the past years!
+Eleven new assignment operators were added:
+
+ += -= *= /= %= **= <<= >>= &= ^= |=
+
+For example,
+
+ A += B
+
+is similar to
+
+ A = A + B
+
+except that A is evaluated only once (relevant when A is something
+like dict[index].attr).
+
+However, if A is a mutable object, A may be modified in place. Thus,
+if A is a number or a string, A += B has the same effect as A = A+B
+(except A is only evaluated once); but if a is a list, A += B has the
+same effect as A.extend(B)!
+
+Classes and built-in object types can override the new operators in
+order to implement the in-place behavior; the not-in-place behavior is
+used automatically as a fallback when an object doesn't implement the
+in-place behavior. For classes, the method name is derived from the
+method name for the corresponding not-in-place operator by inserting
+an 'i' in front of the name, e.g. __iadd__ implements in-place
+__add__.
+
+Augmented assignment was implemented by Thomas Wouters.
+
+
+List Comprehensions
+-------------------
+
+This is a flexible new notation for lists whose elements are computed
+from another list (or lists). The simplest form is:
+
+ [<expression> for <variable> in <sequence>]
+
+For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
+This is more efficient than a for loop with a list.append() call.
+
+You can also add a condition:
+
+ [<expression> for <variable> in <sequence> if <condition>]
+
+For example, [w for w in words if w == w.lower()] would yield the list
+of words that contain no uppercase characters. This is more efficient
+than a for loop with an if statement and a list.append() call.
+
+You can also have nested for loops and more than one 'if' clause. For
+example, here's a function that flattens a sequence of sequences::
+
+ def flatten(seq):
+ return [x for subseq in seq for x in subseq]
+
+ flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
+
+This prints
+
+ [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+
+List comprehensions originated as a patch set from Greg Ewing; Skip
+Montanaro and Thomas Wouters also contributed. Described by PEP 202.
+
+
+Extended Import Statement
+-------------------------
+
+Many people have asked for a way to import a module under a different
+name. This can be accomplished like this:
+
+ import foo
+ bar = foo
+ del foo
+
+but this common idiom gets old quickly. A simple extension of the
+import statement now allows this to be written as follows:
+
+ import foo as bar
+
+There's also a variant for 'from ... import':
+
+ from foo import bar as spam
+
+This also works with packages; e.g. you can write this:
+
+ import test.regrtest as regrtest
+
+Note that 'as' is not a new keyword -- it is recognized only in this
+context (this is only possible because the syntax for the import
+statement doesn't involve expressions).
+
+Implemented by Thomas Wouters. Described by PEP 221.
+
+
+Extended Print Statement
+------------------------
+
+Easily the most controversial new feature, this extension to the print
+statement adds an option to make the output go to a different file
+than the default sys.stdout.
+
+For example, to write an error message to sys.stderr, you can now
+write:
+
+ print >> sys.stderr, "Error: bad dog!"
+
+As a special feature, if the expression used to indicate the file
+evaluates to None, the current value of sys.stdout is used. Thus:
+
+ print >> None, "Hello world"
+
+is equivalent to
+
+ print "Hello world"
+
+Design and implementation by Barry Warsaw. Described by PEP 214.
+
+
+Optional Collection of Cyclical Garbage
+---------------------------------------
+
+Python is now equipped with a garbage collector that can hunt down
+cyclical references between Python objects. It's no replacement for
+reference counting; in fact, it depends on the reference counts being
+correct, and decides that a set of objects belong to a cycle if all
+their reference counts can be accounted for from their references to
+each other. This devious scheme was first proposed by Eric Tiedemann,
+and brought to implementation by Neil Schemenauer.
+
+There's a module "gc" that lets you control some parameters of the
+garbage collection. There's also an option to the configure script
+that lets you enable or disable the garbage collection. In 2.0b1,
+it's on by default, so that we (hopefully) can collect decent user
+experience with this new feature. There are some questions about its
+performance. If it proves to be too much of a problem, we'll turn it
+off by default in the final 2.0 release.
+
+
+Smaller Changes
+---------------
+
+A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
+map(None, seq1, seq2, ...) when the sequences have the same length;
+i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
+the lists are not all the same length, the shortest list wins:
+zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
+
+sys.version_info is a tuple (major, minor, micro, level, serial).
+
+Dictionaries have an odd new method, setdefault(key, default).
+dict.setdefault(key, default) returns dict[key] if it exists; if not,
+it sets dict[key] to default and returns that value. Thus:
+
+ dict.setdefault(key, []).append(item)
+
+does the same work as this common idiom:
+
+ if not dict.has_key(key):
+ dict[key] = []
+ dict[key].append(item)
+
+There are two new variants of SyntaxError that are raised for
+indentation-related errors: IndentationError and TabError.
+
+Changed \x to consume exactly two hex digits; see PEP 223. Added \U
+escape that consumes exactly eight hex digits.
+
+The limits on the size of expressions and file in Python source code
+have been raised from 2**16 to 2**32. Previous versions of Python
+were limited because the maximum argument size the Python VM accepted
+was 2**16. This limited the size of object constructor expressions,
+e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
+limit was raised thanks to a patch by Charles Waldman that effectively
+fixes the problem. It is now much more likely that you will be
+limited by available memory than by an arbitrary limit in Python.
+
+The interpreter's maximum recursion depth can be modified by Python
+programs using sys.getrecursionlimit and sys.setrecursionlimit. This
+limit is the maximum number of recursive calls that can be made by
+Python code. The limit exists to prevent infinite recursion from
+overflowing the C stack and causing a core dump. The default value is
+1000. The maximum safe value for a particular platform can be found
+by running Misc/find_recursionlimit.py.
+
+New Modules and Packages
+------------------------
+
+atexit - for registering functions to be called when Python exits.
+
+imputil - Greg Stein's alternative API for writing custom import
+hooks.
+
+pyexpat - an interface to the Expat XML parser, contributed by Paul
+Prescod.
+
+xml - a new package with XML support code organized (so far) in three
+subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
+would fill a volume. There's a special feature whereby a
+user-installed package named _xmlplus overrides the standard
+xmlpackage; this is intended to give the XML SIG a hook to distribute
+backwards-compatible updates to the standard xml package.
+
+webbrowser - a platform-independent API to launch a web browser.
+
+
+Changed Modules
+---------------
+
+array -- new methods for array objects: count, extend, index, pop, and
+remove
+
+binascii -- new functions b2a_hex and a2b_hex that convert between
+binary data and its hex representation
+
+calendar -- Many new functions that support features including control
+over which day of the week is the first day, returning strings instead
+of printing them. Also new symbolic constants for days of week,
+e.g. MONDAY, ..., SUNDAY.
+
+cgi -- FieldStorage objects have a getvalue method that works like a
+dictionary's get method and returns the value attribute of the object.
+
+ConfigParser -- The parser object has new methods has_option,
+remove_section, remove_option, set, and write. They allow the module
+to be used for writing config files as well as reading them.
+
+ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
+optionally support the RFC 959 REST command.
+
+gzip -- readline and readlines now accept optional size arguments
+
+httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
+the module doc strings for details.
+
+locale -- implement getdefaultlocale for Win32 and Macintosh
+
+marshal -- no longer dumps core when marshaling deeply nested or
+recursive data structures
+
+os -- new functions isatty, seteuid, setegid, setreuid, setregid
+
+os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
+support under Unix.
+
+os/pty -- support for openpty and forkpty
+
+os.path -- fix semantics of os.path.commonprefix
+
+smtplib -- support for sending very long messages
+
+socket -- new function getfqdn()
+
+readline -- new functions to read, write and truncate history files.
+The readline section of the library reference manual contains an
+example.
+
+select -- add interface to poll system call
+
+shutil -- new copyfileobj function
+
+SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
+HTTP server.
+
+Tkinter -- optimization of function flatten
+
+urllib -- scans environment variables for proxy configuration,
+e.g. http_proxy.
+
+whichdb -- recognizes dumbdbm format
+
+
+Obsolete Modules
+----------------
+
+None. However note that 1.6 made a whole slew of modules obsolete:
+stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
+poly, zmod, strop, util, whatsound.
+
+
+Changed, New, Obsolete Tools
+----------------------------
+
+None.
+
+
+C-level Changes
+---------------
+
+Several cleanup jobs were carried out throughout the source code.
+
+All C code was converted to ANSI C; we got rid of all uses of the
+Py_PROTO() macro, which makes the header files a lot more readable.
+
+Most of the portability hacks were moved to a new header file,
+pyport.h; several other new header files were added and some old
+header files were removed, in an attempt to create a more rational set
+of header files. (Few of these ever need to be included explicitly;
+they are all included by Python.h.)
+
+Trent Mick ensured portability to 64-bit platforms, under both Linux
+and Win64, especially for the new Intel Itanium processor. Mick also
+added large file support for Linux64 and Win64.
+
+The C APIs to return an object's size have been update to consistently
+use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
+previous versions, the abstract interfaces used PyXXX_Length and the
+concrete interfaces used PyXXX_Size. The old names,
+e.g. PyObject_Length, are still available for backwards compatibility
+at the API level, but are deprecated.
+
+The PyOS_CheckStack function has been implemented on Windows by
+Fredrik Lundh. It prevents Python from failing with a stack overflow
+on Windows.
+
+The GC changes resulted in creation of two new slots on object,
+tp_traverse and tp_clear. The augmented assignment changes result in
+the creation of a new slot for each in-place operator.
+
+The GC API creates new requirements for container types implemented in
+C extension modules. See Include/objimpl.h for details.
+
+PyErr_Format has been updated to automatically calculate the size of
+the buffer needed to hold the formatted result string. This change
+prevents crashes caused by programmer error.
+
+New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
+
+PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
+that are the same as their non-Ex counterparts except they take an
+extra flag argument that tells them to close the file when done.
+
+XXX There were other API changes that should be fleshed out here.
+
+
+Windows Changes
+---------------
+
+New popen2/popen3/peopen4 in os module (see Changed Modules above).
+
+os.popen is much more usable on Windows 95 and 98. See Microsoft
+Knowledge Base article Q150956. The Win9x workaround described there
+is implemented by the new w9xpopen.exe helper in the root of your
+Python installation. Note that Python uses this internally; it is not
+a standalone program.
+
+Administrator privileges are no longer required to install Python
+on Windows NT or Windows 2000. If you have administrator privileges,
+Python's registry info will be written under HKEY_LOCAL_MACHINE.
+Otherwise the installer backs off to writing Python's registry info
+under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
+uses of Python, but will prevent some advanced uses from working
+(for example, running a Python script as an NT service, or possibly
+from CGI).
+
+[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
+installer; instead, it installs the needed Tcl/Tk files directly in the
+Python directory. If you already have a Tcl/Tk installation, this
+wastes some disk space (about 4 Megs) but avoids problems with
+conflicting Tcl/Tk installations, and makes it much easier for Python
+to ensure that Tcl/Tk can find all its files.
+
+[This was new in 1.6] The Windows installer now installs by default in
+\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
+
+
+Updates to the changes between 1.5.2 and 1.6
+--------------------------------------------
+
+The 1.6 NEWS file can't be changed after the release is done, so here
+is some late-breaking news:
+
+New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
+and changes to getlocale() and setlocale().
+
+The new module is now enabled per default.
+
+It is not true that the encodings codecs cannot be used for normal
+strings: the string.encode() (which is also present on 8-bit strings
+!) allows using them for 8-bit strings too, e.g. to convert files from
+cp1252 (Windows) to latin-1 or vice-versa.
+
+Japanese codecs are available from Tamito KAJIYAMA:
+http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
+
+
+======================================================================
+
+
=======================================
==> Release 1.6 (September 5, 2000) <==
=======================================
- Removed the unused last_is_sticky argument from the internal
_PyTuple_Resize(). If this affects you, you were cheating.
-
-
-======================================================================
-
-
-What's New in Python 2.1 (final)?
-=================================
-
-We only changed a few things since the last release candidate, all in
-Python library code:
-
-- A bug in the locale module was fixed that affected locales which
- define no grouping for numeric formatting.
-
-- A few bugs in the weakref module's implementations of weak
- dictionaries (WeakValueDictionary and WeakKeyDictionary) were fixed,
- and the test suite was updated to check for these bugs.
-
-- An old bug in the os.path.walk() function (introduced in Python
- 2.0!) was fixed: a non-existent file would cause an exception
- instead of being ignored.
-
-- Fixed a few bugs in the new symtable module found by Neil Norwitz's
- PyChecker.
-
-
-What's New in Python 2.1c2?
-===========================
-
-A flurry of small changes, and one showstopper fixed in the nick of
-time made it necessary to release another release candidate. The list
-here is the *complete* list of patches (except version updates):
-
-Core
-
-- Tim discovered a nasty bug in the dictionary code, caused by
- PyDict_Next() calling dict_resize(), and the GC code's use of
- PyDict_Next() violating an assumption in dict_items(). This was
- fixed with considerable amounts of band-aid, but the net effect is a
- saner and more robust implementation.
-
-- Made a bunch of symbols static that were accidentally global.
-
-Build and Ports
-
-- The setup.py script didn't check for a new enough version of zlib
- (1.1.3 is needed). Now it does.
-
-- Changed "make clean" target to also remove shared libraries.
-
-- Added a more general warning about the SGI Irix optimizer to README.
-
-Library
-
-- Fix a bug in urllib.basejoin("http://host", "../file.html") which
- omitted the slash between host and file.html.
-
-- The mailbox module's _Mailbox class contained a completely broken
- and undocumented seek() method. Ripped it out.
-
-- Fixed a bunch of typos in various library modules (urllib2, smtpd,
- sgmllib, netrc, chunk) found by Neil Norwitz's PyChecker.
-
-- Fixed a few last-minute bugs in unittest.
-
-Extensions
-
-- Reverted the patch to the OpenSSL code in socketmodule.c to support
- RAND_status() and the EGD, and the subsequent patch that tried to
- fix it for pre-0.9.5 versions; the problem with the patch is that on
- some systems it issues a warning whenever socket is imported, and
- that's unacceptable.
-
-Tests
-
-- Fixed the pickle tests to work with "import test.test_pickle".
-
-- Tweaked test_locale.py to actually run the test Windows.
-
-- In distutils/archive_util.py, call zipfile.ZipFile() with mode "w",
- not "wb" (which is not a valid mode at all).
-
-- Fix pstats browser crashes. Import readline if it exists to make
- the user interface nicer.
-
-- Add "import thread" to the top of test modules that import the
- threading module (test_asynchat and test_threadedtempfile). This
- prevents test failures caused by a broken threading module resulting
- from a previously caught failed import.
-
-- Changed test_asynchat.py to set the SO_REUSEADDR option; this was
- needed on some platforms (e.g. Solaris 8) when the tests are run
- twice in succession.
-
-- Skip rather than fail test_sunaudiodev if no audio device is found.
-
-
-What's New in Python 2.1c1?
-===========================
-
-This list was significantly updated when 2.1c2 was released; the 2.1c1
-release didn't mention most changes that were actually part of 2.1c1:
-
-Legal
-
-- Copyright was assigned to the Python Software Foundation (PSF) and a
- PSF license (very similar to the CNRI license) was added.
-
-- The CNRI copyright notice was updated to include 2001.
-
-Core
-
-- After a public outcry, assignment to __debug__ is no longer illegal;
- instead, a warning is issued. It will become illegal in 2.2.
-
-- Fixed a core dump with "%#x" % 0, and changed the semantics so that
- "%#x" now always prepends "0x", even if the value is zero.
-
-- Fixed some nits in the bytecode compiler.
-
-- Fixed core dumps when calling certain kinds of non-functions.
-
-- Fixed various core dumps caused by reference count bugs.
-
-Build and Ports
-
-- Use INSTALL_SCRIPT to install script files.
-
-- New port: SCO Unixware 7, by Billy G. Allie.
-
-- Updated RISCOS port.
-
-- Updated BeOS port and notes.
-
-- Various other porting problems resolved.
-
-Library
-
-- The TERMIOS and SOCKET modules are now truly obsolete and
- unnecessary. Their symbols are incorporated in the termios and
- socket modules.
-
-- Fixed some 64-bit bugs in pickle, cPickle, and struct, and added
- better tests for pickling.
-
-- threading: make Condition.wait() robust against KeyboardInterrupt.
-
-- zipfile: add support to zipfile to support opening an archive
- represented by an open file rather than a file name. Fix bug where
- the archive was not properly closed. Fixed a bug in this bugfix
- where flush() was called for a read-only file.
-
-- imputil: added an uninstall() method to the ImportManager.
-
-- Canvas: fixed bugs in lower() and tkraise() methods.
-
-- SocketServer: API change (added overridable close_request() method)
- so that the TCP server can explicitly close the request.
-
-- pstats: Eric Raymond added a simple interactive statistics browser,
- invoked when the module is run as a script.
-
-- locale: fixed a problem in format().
-
-- webbrowser: made it work when the BROWSER environment variable has a
- value like "/usr/bin/netscape". Made it auto-detect Konqueror for
- KDE 2. Fixed some other nits.
-
-- unittest: changes to allow using a different exception than
- AssertionError, and added a few more function aliases. Some other
- small changes.
-
-- urllib, urllib2: fixed redirect problems and a coupleof other nits.
-
-- asynchat: fixed a critical bug in asynchat that slipped through the
- 2.1b2 release. Fixed another rare bug.
-
-- Fix some unqualified except: clauses (always a bad code example).
-
-XML
-
-- pyexpat: new API get_version_string().
-
-- Fixed some minidom bugs.
-
-Extensions
-
-- Fixed a core dump in _weakref. Removed the weakref.mapping()
- function (it adds nothing to the API).
-
-- Rationalized the use of header files in the readline module, to make
- it compile (albeit with some warnings) with the very recent readline
- 4.2, without breaking for earlier versions.
-
-- Hopefully fixed a buffering problem in linuxaudiodev.
-
-- Attempted a fix to make the OpenSSL support in the socket module
- work again with pre-0.9.5 versions of OpenSSL.
-
-Tests
-
-- Added a test case for asynchat and asyncore.
-
-- Removed coupling between tests where one test failing could break
- another.
-
-Tools
-
-- Ping added an interactive help browser to pydoc, fixed some nits
- in the rest of the pydoc code, and added some features to his
- inspect module.
-
-- An updated python-mode.el version 4.1 which integrates Ken
- Manheimer's pdbtrack.el. This makes debugging Python code via pdb
- much nicer in XEmacs and Emacs. When stepping through your program
- with pdb, in either the shell window or the *Python* window, the
- source file and line will be tracked by an arrow. Very cool!
-
-- IDLE: syntax warnings in interactive mode are changed into errors.
-
-- Some improvements to Tools/webchecker (ignore some more URL types,
- follow some more links).
-
-- Brought the Tools/compiler package up to date.
-
-
-What's New in Python 2.1 beta 2?
-================================
-
-(Unlisted are many fixed bugs, more documentation, etc.)
-
-Core language, builtins, and interpreter
-
-- The nested scopes work (enabled by "from __future__ import
- nested_scopes") is completed; in particular, the future now extends
- into code executed through exec, eval() and execfile(), and into the
- interactive interpreter.
-
-- When calling a base class method (e.g. BaseClass.__init__(self)),
- this is now allowed even if self is not strictly spoken a class
- instance (e.g. when using metaclasses or the Don Beaudry hook).
-
-- Slice objects are now comparable but not hashable; this prevents
- dict[:] from being accepted but meaningless.
-
-- Complex division is now calculated using less braindead algorithms.
- This doesn't change semantics except it's more likely to give useful
- results in extreme cases. Complex repr() now uses full precision
- like float repr().
-
-- sgmllib.py now calls handle_decl() for simple <!...> declarations.
-
-- It is illegal to assign to the name __debug__, which is set when the
- interpreter starts. It is effectively a compile-time constant.
-
-- A warning will be issued if a global statement for a variable
- follows a use or assignment of that variable.
-
-Standard library
-
-- unittest.py, a unit testing framework by Steve Purcell (PyUNIT,
- inspired by JUnit), is now part of the standard library. You now
- have a choice of two testing frameworks: unittest requires you to
- write testcases as separate code, doctest gathers them from
- docstrings. Both approaches have their advantages and
- disadvantages.
-
-- A new module Tix was added, which wraps the Tix extension library
- for Tk. With that module, it is not necessary to statically link
- Tix with _tkinter, since Tix will be loaded with Tcl's "package
- require" command. See Demo/tix/.
-
-- tzparse.py is now obsolete.
-
-- In gzip.py, the seek() and tell() methods are removed -- they were
- non-functional anyway, and it's better if callers can test for their
- existence with hasattr().
-
-Python/C API
-
-- PyDict_Next(): it is now safe to call PyDict_SetItem() with a key
- that's already in the dictionary during a PyDict_Next() iteration.
- This used to fail occasionally when a dictionary resize operation
- could be triggered that would rehash all the keys. All other
- modifications to the dictionary are still off-limits during a
- PyDict_Next() iteration!
-
-- New extended APIs related to passing compiler variables around.
-
-- New abstract APIs PyObject_IsInstance(), PyObject_IsSubclass()
- implement isinstance() and issubclass().
-
-- Py_BuildValue() now has a "D" conversion to create a Python complex
- number from a Py_complex C value.
-
-- Extensions types which support weak references must now set the
- field allocated for the weak reference machinery to NULL themselves;
- this is done to avoid the cost of checking each object for having a
- weakly referencable type in PyObject_INIT(), since most types are
- not weakly referencable.
-
-- PyFrame_FastToLocals() and PyFrame_LocalsToFast() copy bindings for
- free variables and cell variables to and from the frame's f_locals.
-
-- Variants of several functions defined in pythonrun.h have been added
- to support the nested_scopes future statement. The variants all end
- in Flags and take an extra argument, a PyCompilerFlags *; examples:
- PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These
- variants may be removed in Python 2.2, when nested scopes are
- mandatory.
-
-Distutils
-
-- the sdist command now writes a PKG-INFO file, as described in PEP 241,
- into the release tree.
-
-- several enhancements to the bdist_wininst command from Thomas Heller
- (an uninstaller, more customization of the installer's display)
-
-- from Jack Jansen: added Mac-specific code to generate a dialog for
- users to specify the command-line (because providing a command-line with
- MacPython is awkward). Jack also made various fixes for the Mac
- and the Metrowerks compiler.
-
-- added 'platforms' and 'keywords' to the set of metadata that can be
- specified for a distribution.
-
-- applied patches from Jason Tishler to make the compiler class work with
- Cygwin.
-
-
-What's New in Python 2.1 beta 1?
-================================
-
-Core language, builtins, and interpreter
-
-- Following an outcry from the community about the amount of code
- broken by the nested scopes feature introduced in 2.1a2, we decided
- to make this feature optional, and to wait until Python 2.2 (or at
- least 6 months) to make it standard. The option can be enabled on a
- per-module basis by adding "from __future__ import nested_scopes" at
- the beginning of a module (before any other statements, but after
- comments and an optional docstring). See PEP 236 (Back to the
- __future__) for a description of the __future__ statement. PEP 227
- (Statically Nested Scopes) has been updated to reflect this change,
- and to clarify the semantics in a number of endcases.
-
-- The nested scopes code, when enabled, has been hardened, and most
- bugs and memory leaks in it have been fixed.
-
-- Compile-time warnings are now generated for a number of conditions
- that will break or change in meaning when nested scopes are enabled:
-
- - Using "from...import *" or "exec" without in-clause in a function
- scope that also defines a lambda or nested function with one or
- more free (non-local) variables. The presence of the import* or
- bare exec makes it impossible for the compiler to determine the
- exact set of local variables in the outer scope, which makes it
- impossible to determine the bindings for free variables in the
- inner scope. To avoid the warning about import *, change it into
- an import of explicitly name object, or move the import* statement
- to the global scope; to avoid the warning about bare exec, use
- exec...in... (a good idea anyway -- there's a possibility that
- bare exec will be deprecated in the future).
-
- - Use of a global variable in a nested scope with the same name as a
- local variable in a surrounding scope. This will change in
- meaning with nested scopes: the name in the inner scope will
- reference the variable in the outer scope rather than the global
- of the same name. To avoid the warning, either rename the outer
- variable, or use a global statement in the inner function.
-
-- An optional object allocator has been included. This allocator is
- optimized for Python objects and should be faster and use less memory
- than the standard system allocator. It is not enabled by default
- because of possible thread safety problems. The allocator is only
- protected by the Python interpreter lock and it is possible that some
- extension modules require a thread safe allocator. The object
- allocator can be enabled by providing the "--with-pymalloc" option to
- configure.
-
-Standard library
-
-- pyexpat now detects the expat version if expat.h defines it. A
- number of additional handlers are provided, which are only available
- since expat 1.95. In addition, the methods SetParamEntityParsing and
- GetInputContext of Parser objects are available with 1.95.x
- only. Parser objects now provide the ordered_attributes and
- specified_attributes attributes. A new module expat.model was added,
- which offers a number of additional constants if 1.95.x is used.
-
-- xml.dom offers the new functions registerDOMImplementation and
- getDOMImplementation.
-
-- xml.dom.minidom offers a toprettyxml method. A number of DOM
- conformance issues have been resolved. In particular, Element now
- has an hasAttributes method, and the handling of namespaces was
- improved.
-
-- Ka-Ping Yee contributed two new modules: inspect.py, a module for
- getting information about live Python code, and pydoc.py, a module
- for interactively converting docstrings to HTML or text.
- Tools/scripts/pydoc, which is now automatically installed into
- <prefix>/bin, uses pydoc.py to display documentation; try running
- "pydoc -h" for instructions. "pydoc -g" pops up a small GUI that
- lets you browse the module docstrings using a web browser.
-
-- New library module difflib.py, primarily packaging the SequenceMatcher
- class at the heart of the popular ndiff.py file-comparison tool.
-
-- doctest.py (a framework for verifying Python code examples in docstrings)
- is now part of the std library.
-
-Windows changes
-
-- A new entry in the Start menu, "Module Docs", runs "pydoc -g" -- a
- small GUI that lets you browse the module docstrings using your
- default web browser.
-
-- Import is now case-sensitive. PEP 235 (Import on Case-Insensitive
- Platforms) is implemented. See
-
- http://python.sourceforge.net/peps/pep-0235.html
-
- for full details, especially the "Current Lower-Left Semantics" section.
- The new Windows import rules are simpler than before:
-
- A. If the PYTHONCASEOK environment variable exists, same as
- before: silently accept the first case-insensitive match of any
- kind; raise ImportError if none found.
-
- B. Else search sys.path for the first case-sensitive match; raise
- ImportError if none found.
-
- The same rules have been implemented on other platforms with case-
- insensitive but case-preserving filesystems too (including Cygwin, and
- several flavors of Macintosh operating systems).
-
-- winsound module: Under Win9x, winsound.Beep() now attempts to simulate
- what it's supposed to do (and does do under NT and 2000) via direct
- port manipulation. It's unknown whether this will work on all systems,
- but it does work on my Win98SE systems now and was known to be useless on
- all Win9x systems before.
-
-- Build: Subproject _test (effectively) renamed to _testcapi.
-
-New platforms
-
-- 2.1 should compile and run out of the box under MacOS X, even using HFS+.
- Thanks to Steven Majewski!
-
-- 2.1 should compile and run out of the box on Cygwin. Thanks to Jason
- Tishler!
-
-- 2.1 contains new files and patches for RISCOS, thanks to Dietmar
- Schwertberger! See RISCOS/README for more information -- it seems
- that because of the bizarre filename conventions on RISCOS, no port
- to that platform is easy.
-
-
-What's New in Python 2.1 alpha 2?
-=================================
-
-Core language, builtins, and interpreter
-
-- Scopes nest. If a name is used in a function or class, but is not
- local, the definition in the nearest enclosing function scope will
- be used. One consequence of this change is that lambda statements
- could reference variables in the namespaces where the lambda is
- defined. In some unusual cases, this change will break code.
-
- In all previous version of Python, names were resolved in exactly
- three namespaces -- the local namespace, the global namespace, and
- the builtin namespace. According to this old definition, if a
- function A is defined within a function B, the names bound in B are
- not visible in A. The new rules make names bound in B visible in A,
- unless A contains a name binding that hides the binding in B.
-
- Section 4.1 of the reference manual describes the new scoping rules
- in detail. The test script in Lib/test/test_scope.py demonstrates
- some of the effects of the change.
-
- The new rules will cause existing code to break if it defines nested
- functions where an outer function has local variables with the same
- name as globals or builtins used by the inner function. Example:
-
- def munge(str):
- def helper(x):
- return str(x)
- if type(str) != type(''):
- str = helper(str)
- return str.strip()
-
- Under the old rules, the name str in helper() is bound to the
- builtin function str(). Under the new rules, it will be bound to
- the argument named str and an error will occur when helper() is
- called.
-
-- The compiler will report a SyntaxError if "from ... import *" occurs
- in a function or class scope. The language reference has documented
- that this case is illegal, but the compiler never checked for it.
- The recent introduction of nested scope makes the meaning of this
- form of name binding ambiguous. In a future release, the compiler
- may allow this form when there is no possibility of ambiguity.
-
-- repr(string) is easier to read, now using hex escapes instead of octal,
- and using \t, \n and \r instead of \011, \012 and \015 (respectively):
-
- >>> "\texample \r\n" + chr(0) + chr(255)
- '\texample \r\n\x00\xff' # in 2.1
- '\011example \015\012\000\377' # in 2.0
-
-- Functions are now compared and hashed by identity, not by value, since
- the func_code attribute is writable.
-
-- Weak references (PEP 205) have been added. This involves a few
- changes in the core, an extension module (_weakref), and a Python
- module (weakref). The weakref module is the public interface. It
- includes support for "explicit" weak references, proxy objects, and
- mappings with weakly held values.
-
-- A 'continue' statement can now appear in a try block within the body
- of a loop. It is still not possible to use continue in a finally
- clause.
-
-Standard library
-
-- mailbox.py now has a new class, PortableUnixMailbox which is
- identical to UnixMailbox but uses a more portable scheme for
- determining From_ separators. Also, the constructors for all the
- classes in this module have a new optional `factory' argument, which
- is a callable used when new message classes must be instantiated by
- the next() method.
-
-- random.py is now self-contained, and offers all the functionality of
- the now-deprecated whrandom.py. See the docs for details. random.py
- also supports new functions getstate() and setstate(), for saving
- and restoring the internal state of the generator; and jumpahead(n),
- for quickly forcing the internal state to be the same as if n calls to
- random() had been made. The latter is particularly useful for multi-
- threaded programs, creating one instance of the random.Random() class for
- each thread, then using .jumpahead() to force each instance to use a
- non-overlapping segment of the full period.
-
-- random.py's seed() function is new. For bit-for-bit compatibility with
- prior releases, use the whseed function instead. The new seed function
- addresses two problems: (1) The old function couldn't produce more than
- about 2**24 distinct internal states; the new one about 2**45 (the best
- that can be done in the Wichmann-Hill generator). (2) The old function
- sometimes produced identical internal states when passed distinct
- integers, and there was no simple way to predict when that would happen;
- the new one guarantees to produce distinct internal states for all
- arguments in [0, 27814431486576L).
-
-- The socket module now supports raw packets on Linux. The socket
- family is AF_PACKET.
-
-- test_capi.py is a start at running tests of the Python C API. The tests
- are implemented by the new Modules/_testmodule.c.
-
-- A new extension module, _symtable, provides provisional access to the
- internal symbol table used by the Python compiler. A higher-level
- interface will be added on top of _symtable in a future release.
-
-- Removed the obsolete soundex module.
-
-- xml.dom.minidom now uses the standard DOM exceptions. Node supports
- the isSameNode method; NamedNodeMap the get method.
-
-- xml.sax.expatreader supports the lexical handler property; it
- generates comment, startCDATA, and endCDATA events.
-
-Windows changes
-
-- Build procedure: the zlib project is built in a different way that
- ensures the zlib header files used can no longer get out of synch with
- the zlib binary used. See PCbuild\readme.txt for details. Your old
- zlib-related directories can be deleted; you'll need to download fresh
- source for zlib and unpack it into a new directory.
-
-- Build: New subproject _test for the benefit of test_capi.py (see above).
-
-- Build: New subproject _symtable, for new DLL _symtable.pyd (a nascent
- interface to some Python compiler internals).
-
-- Build: Subproject ucnhash is gone, since the code was folded into the
- unicodedata subproject.
-
-What's New in Python 2.1 alpha 1?
-=================================
-
-Core language, builtins, and interpreter
-
-- There is a new Unicode companion to the PyObject_Str() API
- called PyObject_Unicode(). It behaves in the same way as the
- former, but assures that the returned value is an Unicode object
- (applying the usual coercion if necessary).
-
-- The comparison operators support "rich comparison overloading" (PEP
- 207). C extension types can provide a rich comparison function in
- the new tp_richcompare slot in the type object. The cmp() function
- and the C function PyObject_Compare() first try the new rich
- comparison operators before trying the old 3-way comparison. There
- is also a new C API PyObject_RichCompare() (which also falls back on
- the old 3-way comparison, but does not constrain the outcome of the
- rich comparison to a Boolean result).
-
- The rich comparison function takes two objects (at least one of
- which is guaranteed to have the type that provided the function) and
- an integer indicating the opcode, which can be Py_LT, Py_LE, Py_EQ,
- Py_NE, Py_GT, Py_GE (for <, <=, ==, !=, >, >=), and returns a Python
- object, which may be NotImplemented (in which case the tp_compare
- slot function is used as a fallback, if defined).
-
- Classes can overload individual comparison operators by defining one
- or more of the methods__lt__, __le__, __eq__, __ne__, __gt__,
- __ge__. There are no explicit "reflected argument" versions of
- these; instead, __lt__ and __gt__ are each other's reflection,
- likewise for__le__ and __ge__; __eq__ and __ne__ are their own
- reflection (similar at the C level). No other implications are
- made; in particular, Python does not assume that == is the Boolean
- inverse of !=, or that < is the Boolean inverse of >=. This makes
- it possible to define types with partial orderings.
-
- Classes or types that want to implement (in)equality tests but not
- the ordering operators (i.e. unordered types) should implement ==
- and !=, and raise an error for the ordering operators.
-
- It is possible to define types whose rich comparison results are not
- Boolean; e.g. a matrix type might want to return a matrix of bits
- for A < B, giving elementwise comparisons. Such types should ensure
- that any interpretation of their value in a Boolean context raises
- an exception, e.g. by defining __nonzero__ (or the tp_nonzero slot
- at the C level) to always raise an exception.
-
-- Complex numbers use rich comparisons to define == and != but raise
- an exception for <, <=, > and >=. Unfortunately, this also means
- that cmp() of two complex numbers raises an exception when the two
- numbers differ. Since it is not mathematically meaningful to compare
- complex numbers except for equality, I hope that this doesn't break
- too much code.
-
-- The outcome of comparing non-numeric objects of different types is
- not defined by the language, other than that it's arbitrary but
- consistent (see the Reference Manual). An implementation detail changed
- in 2.1a1 such that None now compares less than any other object. Code
- relying on this new behavior (like code that relied on the previous
- behavior) does so at its own risk.
-
-- Functions and methods now support getting and setting arbitrarily
- named attributes (PEP 232). Functions have a new __dict__
- (a.k.a. func_dict) which hold the function attributes. Methods get
- and set attributes on their underlying im_func. It is a TypeError
- to set an attribute on a bound method.
-
-- The xrange() object implementation has been improved so that
- xrange(sys.maxint) can be used on 64-bit platforms. There's still a
- limitation that in this case len(xrange(sys.maxint)) can't be
- calculated, but the common idiom "for i in xrange(sys.maxint)" will
- work fine as long as the index i doesn't actually reach 2**31.
- (Python uses regular ints for sequence and string indices; fixing
- that is much more work.)
-
-- Two changes to from...import:
-
- 1) "from M import X" now works even if (after loading module M)
- sys.modules['M'] is not a real module; it's basically a getattr()
- operation with AttributeError exceptions changed into ImportError.
-
- 2) "from M import *" now looks for M.__all__ to decide which names to
- import; if M.__all__ doesn't exist, it uses M.__dict__.keys() but
- filters out names starting with '_' as before. Whether or not
- __all__ exists, there's no restriction on the type of M.
-
-- File objects have a new method, xreadlines(). This is the fastest
- way to iterate over all lines in a file:
-
- for line in file.xreadlines():
- ...do something to line...
-
- See the xreadlines module (mentioned below) for how to do this for
- other file-like objects.
-
-- Even if you don't use file.xreadlines(), you may expect a speedup on
- line-by-line input. The file.readline() method has been optimized
- quite a bit in platform-specific ways: on systems (like Linux) that
- support flockfile(), getc_unlocked(), and funlockfile(), those are
- used by default. On systems (like Windows) without getc_unlocked(),
- a complicated (but still thread-safe) method using fgets() is used by
- default.
-
- You can force use of the fgets() method by #define'ing
- USE_FGETS_IN_GETLINE at build time (it may be faster than
- getc_unlocked()).
-
- You can force fgets() not to be used by #define'ing
- DONT_USE_FGETS_IN_GETLINE (this is the first thing to try if std test
- test_bufio.py fails -- and let us know if it does!).
-
-- In addition, the fileinput module, while still slower than the other
- methods on most platforms, has been sped up too, by using
- file.readlines(sizehint).
-
-- Support for run-time warnings has been added, including a new
- command line option (-W) to specify the disposition of warnings.
- See the description of the warnings module below.
-
-- Extensive changes have been made to the coercion code. This mostly
- affects extension modules (which can now implement mixed-type
- numerical operators without having to use coercion), but
- occasionally, in boundary cases the coercion semantics have changed
- subtly. Since this was a terrible gray area of the language, this
- is considered an improvement. Also note that __rcmp__ is no longer
- supported -- instead of calling __rcmp__, __cmp__ is called with
- reflected arguments.
-
-- In connection with the coercion changes, a new built-in singleton
- object, NotImplemented is defined. This can be returned for
- operations that wish to indicate they are not implemented for a
- particular combination of arguments. From C, this is
- Py_NotImplemented.
-
-- The interpreter accepts now bytecode files on the command line even
- if they do not have a .pyc or .pyo extension. On Linux, after executing
-
-import imp,sys,string
-magic = string.join(["\\x%.2x" % ord(c) for c in imp.get_magic()],"")
-reg = ':pyc:M::%s::%s:' % (magic, sys.executable)
-open("/proc/sys/fs/binfmt_misc/register","wb").write(reg)
-
- any byte code file can be used as an executable (i.e. as an argument
- to execve(2)).
-
-- %[xXo] formats of negative Python longs now produce a sign
- character. In 1.6 and earlier, they never produced a sign,
- and raised an error if the value of the long was too large
- to fit in a Python int. In 2.0, they produced a sign if and
- only if too large to fit in an int. This was inconsistent
- across platforms (because the size of an int varies across
- platforms), and inconsistent with hex() and oct(). Example:
-
- >>> "%x" % -0x42L
- '-42' # in 2.1
- 'ffffffbe' # in 2.0 and before, on 32-bit machines
- >>> hex(-0x42L)
- '-0x42L' # in all versions of Python
-
- The behavior of %d formats for negative Python longs remains
- the same as in 2.0 (although in 1.6 and before, they raised
- an error if the long didn't fit in a Python int).
-
- %u formats don't make sense for Python longs, but are allowed
- and treated the same as %d in 2.1. In 2.0, a negative long
- formatted via %u produced a sign if and only if too large to
- fit in an int. In 1.6 and earlier, a negative long formatted
- via %u raised an error if it was too big to fit in an int.
-
-- Dictionary objects have an odd new method, popitem(). This removes
- an arbitrary item from the dictionary and returns it (in the form of
- a (key, value) pair). This can be useful for algorithms that use a
- dictionary as a bag of "to do" items and repeatedly need to pick one
- item. Such algorithms normally end up running in quadratic time;
- using popitem() they can usually be made to run in linear time.
-
-Standard library
-
-- In the time module, the time argument to the functions strftime,
- localtime, gmtime, asctime and ctime is now optional, defaulting to
- the current time (in the local timezone).
-
-- The ftplib module now defaults to passive mode, which is deemed a
- more useful default given that clients are often inside firewalls
- these days. Note that this could break if ftplib is used to connect
- to a *server* that is inside a firewall, from outside; this is
- expected to be a very rare situation. To fix that, you can call
- ftp.set_pasv(0).
-
-- The module site now treats .pth files not only for path configuration,
- but also supports extensions to the initialization code: Lines starting
- with import are executed.
-
-- There's a new module, warnings, which implements a mechanism for
- issuing and filtering warnings. There are some new built-in
- exceptions that serve as warning categories, and a new command line
- option, -W, to control warnings (e.g. -Wi ignores all warnings, -We
- turns warnings into errors). warnings.warn(message[, category])
- issues a warning message; this can also be called from C as
- PyErr_Warn(category, message).
-
-- A new module xreadlines was added. This exports a single factory
- function, xreadlines(). The intention is that this code is the
- absolutely fastest way to iterate over all lines in an open
- file(-like) object:
-
- import xreadlines
- for line in xreadlines.xreadlines(file):
- ...do something to line...
-
- This is equivalent to the previous the speed record holder using
- file.readlines(sizehint). Note that if file is a real file object
- (as opposed to a file-like object), this is equivalent:
-
- for line in file.xreadlines():
- ...do something to line...
-
-- The bisect module has new functions bisect_left, insort_left,
- bisect_right and insort_right. The old names bisect and insort
- are now aliases for bisect_right and insort_right. XXX_right
- and XXX_left methods differ in what happens when the new element
- compares equal to one or more elements already in the list: the
- XXX_left methods insert to the left, the XXX_right methods to the
- right. Code that doesn't care where equal elements end up should
- continue to use the old, short names ("bisect" and "insort").
-
-- The new curses.panel module wraps the panel library that forms part
- of SYSV curses and ncurses. Contributed by Thomas Gellekum.
-
-- The SocketServer module now sets the allow_reuse_address flag by
- default in the TCPServer class.
-
-- A new function, sys._getframe(), returns the stack frame pointer of
- the caller. This is intended only as a building block for
- higher-level mechanisms such as string interpolation.
-
-- The pyexpat module supports a number of new handlers, which are
- available only in expat 1.2. If invocation of a callback fails, it
- will report an additional frame in the traceback. Parser objects
- participate now in garbage collection. If expat reports an unknown
- encoding, pyexpat will try to use a Python codec; that works only
- for single-byte charsets. The parser type objects is exposed as
- XMLParserObject.
-
-- xml.dom now offers standard definitions for symbolic node type and
- exception code constants, and a hierarchy of DOM exceptions. minidom
- was adjusted to use them.
-
-- The conformance of xml.dom.minidom to the DOM specification was
- improved. It detects a number of additional error cases; the
- previous/next relationship works even when the tree is modified;
- Node supports the normalize() method; NamedNodeMap, DocumentType and
- DOMImplementation classes were added; Element supports the
- hasAttribute and hasAttributeNS methods; and Text supports the splitText
- method.
-
-Build issues
-
-- For Unix (and Unix-compatible) builds, configuration and building of
- extension modules is now greatly automated. Rather than having to
- edit the Modules/Setup file to indicate which modules should be
- built and where their include files and libraries are, a
- distutils-based setup.py script now takes care of building most
- extension modules. All extension modules built this way are built
- as shared libraries. Only a few modules that must be linked
- statically are still listed in the Setup file; you won't need to
- edit their configuration.
-
-- Python should now build out of the box on Cygwin. If it doesn't,
- mail to Jason Tishler (jlt63 at users.sourceforge.net).
-
-- Python now always uses its own (renamed) implementation of getopt()
- -- there's too much variation among C library getopt()
- implementations.
-
-- C++ compilers are better supported; the CXX macro is always set to a
- C++ compiler if one is found.
-
-Windows changes
-
-- select module: By default under Windows, a select() call
- can specify no more than 64 sockets. Python now boosts
- this Microsoft default to 512. If you need even more than
- that, see the MS docs (you'll need to #define FD_SETSIZE
- and recompile Python from source).
-
-- Support for Windows 3.1, DOS and OS/2 is gone. The Lib/dos-8x3
- subdirectory is no more!
-
-
-What's New in Python 2.0?
-=========================
-
-Below is a list of all relevant changes since release 1.6. Older
-changes are in the file HISTORY. If you are making the jump directly
-from Python 1.5.2 to 2.0, make sure to read the section for 1.6 in the
-HISTORY file! Many important changes listed there.
-
-Alternatively, a good overview of the changes between 1.5.2 and 2.0 is
-the document "What's New in Python 2.0" by Kuchling and Moshe Zadka:
-http://starship.python.net/crew/amk/python/writing/new-python/.
-
---Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)
-
-======================================================================
-
-What's new in 2.0 (since release candidate 1)?
-==============================================
-
-Standard library
-
-- The copy_reg module was modified to clarify its intended use: to
- register pickle support for extension types, not for classes.
- pickle() will raise a TypeError if it is passed a class.
-
-- Fixed a bug in gettext's "normalize and expand" code that prevented
- it from finding an existing .mo file.
-
-- Restored support for HTTP/0.9 servers in httplib.
-
-- The math module was changed to stop raising OverflowError in case of
- underflow, and return 0 instead in underflow cases. Whether Python
- used to raise OverflowError in case of underflow was platform-
- dependent (it did when the platform math library set errno to ERANGE
- on underflow).
-
-- Fixed a bug in StringIO that occurred when the file position was not
- at the end of the file and write() was called with enough data to
- extend past the end of the file.
-
-- Fixed a bug that caused Tkinter error messages to get lost on
- Windows. The bug was fixed by replacing direct use of
- interp->result with Tcl_GetStringResult(interp).
-
-- Fixed bug in urllib2 that caused it to fail when it received an HTTP
- redirect response.
-
-- Several changes were made to distutils: Some debugging code was
- removed from util. Fixed the installer used when an external zip
- program (like WinZip) is not found; the source code for this
- installer is in Misc/distutils. check_lib() was modified to behave
- more like AC_CHECK_LIB by add other_libraries() as a parameter. The
- test for whether installed modules are on sys.path was changed to
- use both normcase() and normpath().
-
-- Several minor bugs were fixed in the xml package (the minidom,
- pulldom, expatreader, and saxutils modules).
-
-- The regression test driver (regrtest.py) behavior when invoked with
- -l changed: It now reports a count of objects that are recognized as
- garbage but not freed by the garbage collector.
-
-- The regression test for the math module was changed to test
- exceptional behavior when the test is run in verbose mode. Python
- cannot yet guarantee consistent exception behavior across platforms,
- so the exception part of test_math is run only in verbose mode, and
- may fail on your platform.
-
-Internals
-
-- PyOS_CheckStack() has been disabled on Win64, where it caused
- test_sre to fail.
-
-Build issues
-
-- Changed compiler flags, so that gcc is always invoked with -Wall and
- -Wstrict-prototypes. Users compiling Python with GCC should see
- exactly one warning, except if they have passed configure the
- --with-pydebug flag. The expected warning is for getopt() in
- Modules/main.c. This warning will be fixed for Python 2.1.
-
-- Fixed configure to add -threads argument during linking on OSF1.
-
-Tools and other miscellany
-
-- The compiler in Tools/compiler was updated to support the new
- language features introduced in 2.0: extended print statement, list
- comprehensions, and augmented assignments. The new compiler should
- also be backwards compatible with Python 1.5.2; the compiler will
- always generate code for the version of the interpreter it runs
- under.
-
-What's new in 2.0 release candidate 1 (since beta 2)?
-=====================================================
-
-What is release candidate 1?
-
-We believe that release candidate 1 will fix all known bugs that we
-intend to fix for the 2.0 final release. This release should be a bit
-more stable than the previous betas. We would like to see even more
-widespread testing before the final release, so we are producing this
-release candidate. The final release will be exactly the same unless
-any show-stopping (or brown bag) bugs are found by testers of the
-release candidate.
-
-All the changes since the last beta release are bug fixes or changes
-to support building Python for specific platforms.
-
-Core language, builtins, and interpreter
-
-- A bug that caused crashes when __coerce__ was used with augmented
- assignment, e.g. +=, was fixed.
-
-- Raise ZeroDivisionError when raising zero to a negative number,
- e.g. 0.0 ** -2.0. Note that math.pow is unrelated to the builtin
- power operator and the result of math.pow(0.0, -2.0) will vary by
- platform. On Linux, it raises a ValueError.
-
-- A bug in Unicode string interpolation was fixed that occasionally
- caused errors with formats including "%%". For example, the
- following expression "%% %s" % u"abc" no longer raises a TypeError.
-
-- Compilation of deeply nested expressions raises MemoryError instead
- of SyntaxError, e.g. eval("[" * 50 + "]" * 50).
-
-- In 2.0b2 on Windows, the interpreter wrote .pyc files in text mode,
- rendering them useless. They are now written in binary mode again.
-
-Standard library
-
-- Keyword arguments are now accepted for most pattern and match object
- methods in SRE, the standard regular expression engine.
-
-- In SRE, fixed error with negative lookahead and lookbehind that
- manifested itself as a runtime error in patterns like "(?<!abc)(def)".
-
-- Several bugs in the Unicode handling and error handling in _tkinter
- were fixed.
-
-- Fix memory management errors in Merge() and Tkapp_Call() routines.
-
-- Several changes were made to cStringIO to make it compatible with
- the file-like object interface and with StringIO. If operations are
- performed on a closed object, an exception is raised. The truncate
- method now accepts a position argument and readline accepts a size
- argument.
-
-- There were many changes made to the linuxaudiodev module and its
- test suite; as a result, a short, unexpected audio sample should now
- play when the regression test is run.
-
- Note that this module is named poorly, because it should work
- correctly on any platform that supports the Open Sound System
- (OSS).
-
- The module now raises exceptions when errors occur instead of
- crashing. It also defines the AFMT_A_LAW format (logarithmic A-law
- audio) and defines a getptr() method that calls the
- SNDCTL_DSP_GETxPTR ioctl defined in the OSS Programmer's Guide.
-
-- The library_version attribute, introduced in an earlier beta, was
- removed because it can not be supported with early versions of the C
- readline library, which provides no way to determine the version at
- compile-time.
-
-- The binascii module is now enabled on Win64.
-
-- tokenize.py no longer suffers "recursion depth" errors when parsing
- programs with very long string literals.
-
-Internals
-
-- Fixed several buffer overflow vulnerabilities in calculate_path(),
- which is called when the interpreter starts up to determine where
- the standard library is installed. These vulnerabilities affect all
- previous versions of Python and can be exploited by setting very
- long values for PYTHONHOME or argv[0]. The risk is greatest for a
- setuid Python script, although use of the wrapper in
- Misc/setuid-prog.c will eliminate the vulnerability.
-
-- Fixed garbage collection bugs in instance creation that were
- triggered when errors occurred during initialization. The solution,
- applied in cPickle and in PyInstance_New(), is to call
- PyObject_GC_Init() after the initialization of the object's
- container attributes is complete.
-
-- pyexpat adds definitions of PyModule_AddStringConstant and
- PyModule_AddObject if the Python version is less than 2.0, which
- provides compatibility with PyXML on Python 1.5.2.
-
-- If the platform has a bogus definition for LONG_BIT (the number of
- bits in a long), an error will be reported at compile time.
-
-- Fix bugs in _PyTuple_Resize() which caused hard-to-interpret garbage
- collection crashes and possibly other, unreported crashes.
-
-- Fixed a memory leak in _PyUnicode_Fini().
-
-Build issues
-
-- configure now accepts a --with-suffix option that specifies the
- executable suffix. This is useful for builds on Cygwin and Mac OS
- X, for example.
-
-- The mmap.PAGESIZE constant is now initialized using sysconf when
- possible, which eliminates a dependency on -lucb for Reliant UNIX.
-
-- The md5 file should now compile on all platforms.
-
-- The select module now compiles on platforms that do not define
- POLLRDNORM and related constants.
-
-- Darwin (Mac OS X): Initial support for static builds on this
- platform.
-
-- BeOS: A number of changes were made to the build and installation
- process. ar-fake now operates on a directory of object files.
- dl_export.h is gone, and its macros now appear on the mwcc command
- line during build on PPC BeOS.
-
-- Platform directory in lib/python2.0 is "plat-beos5" (or
- "plat-beos4", if building on BeOS 4.5), rather than "plat-beos".
-
-- Cygwin: Support for shared libraries, Tkinter, and sockets.
-
-- SunOS 4.1.4_JL: Fix test for directory existence in configure.
-
-Tools and other miscellany
-
-- Removed debugging prints from main used with freeze.
-
-- IDLE auto-indent no longer crashes when it encounters Unicode
- characters.
-
-What's new in 2.0 beta 2 (since beta 1)?
-========================================
-
-Core language, builtins, and interpreter
-
-- Add support for unbounded ints in %d,i,u,x,X,o formats; for example
- "%d" % 2L**64 == "18446744073709551616".
-
-- Add -h and -V command line options to print the usage message and
- Python version number and exit immediately.
-
-- eval() and exec accept Unicode objects as code parameters.
-
-- getattr() and setattr() now also accept Unicode objects for the
- attribute name, which are converted to strings using the default
- encoding before lookup.
-
-- Multiplication on string and Unicode now does proper bounds
- checking; e.g. 'a' * 65536 * 65536 will raise ValueError, "repeated
- string is too long."
-
-- Better error message when continue is found in try statement in a
- loop.
-
-
-Standard library and extensions
-
-- socket module: the OpenSSL code now adds support for RAND_status()
- and EGD (Entropy Gathering Device).
-
-- array: reverse() method of array now works. buffer_info() now does
- argument checking; it still takes no arguments.
-
-- asyncore/asynchat: Included most recent version from Sam Rushing.
-
-- cgi: Accept '&' or ';' as separator characters when parsing form data.
-
-- CGIHTTPServer: Now works on Windows (and perhaps even Mac).
-
-- ConfigParser: When reading the file, options spelled in upper case
- letters are now correctly converted to lowercase.
-
-- copy: Copy Unicode objects atomically.
-
-- cPickle: Fail gracefully when copy_reg can't be imported.
-
-- cStringIO: Implemented readlines() method.
-
-- dbm: Add get() and setdefault() methods to dbm object. Add constant
- `library' to module that names the library used. Added doc strings
- and method names to error messages. Uses configure to determine
- which ndbm.h file to include; Berkeley DB's nbdm and GDBM's ndbm is
- now available options.
-
-- distutils: Update to version 0.9.3.
-
-- dl: Add several dl.RTLD_ constants.
-
-- fpectl: Now supported on FreeBSD.
-
-- gc: Add DEBUG_SAVEALL option. When enabled all garbage objects
- found by the collector will be saved in gc.garbage. This is useful
- for debugging a program that creates reference cycles.
-
-- httplib: Three changes: Restore support for set_debuglevel feature
- of HTTP class. Do not close socket on zero-length response. Do not
- crash when server sends invalid content-length header.
-
-- mailbox: Mailbox class conforms better to qmail specifications.
-
-- marshal: When reading a short, sign-extend on platforms where shorts
- are bigger than 16 bits. When reading a long, repair the unportable
- sign extension that was being done for 64-bit machines. (It assumed
- that signed right shift sign-extends.)
-
-- operator: Add contains(), invert(), __invert__() as aliases for
- __contains__(), inv(), and __inv__() respectively.
-
-- os: Add support for popen2() and popen3() on all platforms where
- fork() exists. (popen4() is still in the works.)
-
-- os: (Windows only:) Add startfile() function that acts like double-
- clicking on a file in Explorer (or passing the file name to the
- DOS "start" command).
-
-- os.path: (Windows, DOS:) Treat trailing colon correctly in
- os.path.join. os.path.join("a:", "b") yields "a:b".
-
-- pickle: Now raises ValueError when an invalid pickle that contains
- a non-string repr where a string repr was expected. This behavior
- matches cPickle.
-
-- posixfile: Remove broken __del__() method.
-
-- py_compile: support CR+LF line terminators in source file.
-
-- readline: Does not immediately exit when ^C is hit when readline and
- threads are configured. Adds definition of rl_library_version. (The
- latter addition requires GNU readline 2.2 or later.)
-
-- rfc822: Domain literals returned by AddrlistClass method
- getdomainliteral() are now properly wrapped in brackets.
-
-- site: sys.setdefaultencoding() should only be called in case the
- standard default encoding ("ascii") is changed. This saves quite a
- few cycles during startup since the first call to
- setdefaultencoding() will initialize the codec registry and the
- encodings package.
-
-- socket: Support for size hint in readlines() method of object returned
- by makefile().
-
-- sre: Added experimental expand() method to match objects. Does not
- use buffer interface on Unicode strings. Does not hang if group id
- is followed by whitespace.
-
-- StringIO: Size hint in readlines() is now supported as documented.
-
-- struct: Check ranges for bytes and shorts.
-
-- urllib: Improved handling of win32 proxy settings. Fixed quote and
- quote_plus functions so that the always encode a comma.
-
-- Tkinter: Image objects are now guaranteed to have unique ids. Set
- event.delta to zero if Tk version doesn't support mousewheel.
- Removed some debugging prints.
-
-- UserList: now implements __contains__().
-
-- webbrowser: On Windows, use os.startfile() instead of os.popen(),
- which works around a bug in Norton AntiVirus 2000 that leads directly
- to a Blue Screen freeze.
-
-- xml: New version detection code allows PyXML to override standard
- XML package if PyXML version is greater than 0.6.1.
-
-- xml.dom: DOM level 1 support for basic XML. Includes xml.dom.minidom
- (conventional DOM), and xml.dom.pulldom, which allows building the DOM
- tree only for nodes which are sufficiently interesting to a specific
- application. Does not provide the HTML-specific extensions. Still
- undocumented.
-
-- xml.sax: SAX 2 support for Python, including all the handler
- interfaces needed to process XML 1.0 compliant XML. Some
- documentation is already available.
-
-- pyexpat: Renamed to xml.parsers.expat since this is part of the new,
- packagized XML support.
-
-
-C API
-
-- Add three new convenience functions for module initialization --
- PyModule_AddObject(), PyModule_AddIntConstant(), and
- PyModule_AddStringConstant().
-
-- Cleaned up definition of NULL in C source code; all definitions were
- removed and add #error to Python.h if NULL isn't defined after
- #include of stdio.h.
-
-- Py_PROTO() macros that were removed in 2.0b1 have been restored for
- backwards compatibility (at the source level) with old extensions.
-
-- A wrapper API was added for signal() and sigaction(). Instead of
- either function, always use PyOS_getsig() to get a signal handler
- and PyOS_setsig() to set one. A new convenience typedef
- PyOS_sighandler_t is defined for the type of signal handlers.
-
-- Add PyString_AsStringAndSize() function that provides access to the
- internal data buffer and size of a string object -- or the default
- encoded version of a Unicode object.
-
-- PyString_Size() and PyString_AsString() accept Unicode objects.
-
-- The standard header <limits.h> is now included by Python.h (if it
- exists). INT_MAX and LONG_MAX will always be defined, even if
- <limits.h> is not available.
-
-- PyFloat_FromString takes a second argument, pend, that was
- effectively useless. It is now officially useless but preserved for
- backwards compatibility. If the pend argument is not NULL, *pend is
- set to NULL.
-
-- PyObject_GetAttr() and PyObject_SetAttr() now accept Unicode objects
- for the attribute name. See note on getattr() above.
-
-- A few bug fixes to argument processing for Unicode.
- PyArg_ParseTupleAndKeywords() now accepts "es#" and "es".
- PyArg_Parse() special cases "s#" for Unicode objects; it returns a
- pointer to the default encoded string data instead of to the raw
- UTF-16.
-
-- Py_BuildValue accepts B format (for bgen-generated code).
-
-
-Internals
-
-- On Unix, fix code for finding Python installation directory so that
- it works when argv[0] is a relative path.
-
-- Added a true unicode_internal_encode() function and fixed the
- unicode_internal_decode function() to support Unicode objects directly
- rather than by generating a copy of the object.
-
-- Several of the internal Unicode tables are much smaller now, and
- the source code should be much friendlier to weaker compilers.
-
-- In the garbage collector: Fixed bug in collection of tuples. Fixed
- bug that caused some instances to be removed from the container set
- while they were still live. Fixed parsing in gc.set_debug() for
- platforms where sizeof(long) > sizeof(int).
-
-- Fixed refcount problem in instance deallocation that only occurred
- when Py_REF_DEBUG was defined and Py_TRACE_REFS was not.
-
-- On Windows, getpythonregpath is now protected against null data in
- registry key.
-
-- On Unix, create .pyc/.pyo files with O_EXCL flag to avoid a race
- condition.
-
-
-Build and platform-specific issues
-
-- Better support of GNU Pth via --with-pth configure option.
-
-- Python/C API now properly exposed to dynamically-loaded extension
- modules on Reliant UNIX.
-
-- Changes for the benefit of SunOS 4.1.4 (really!). mmapmodule.c:
- Don't define MS_SYNC to be zero when it is undefined. Added missing
- prototypes in posixmodule.c.
-
-- Improved support for HP-UX build. Threads should now be correctly
- configured (on HP-UX 10.20 and 11.00).
-
-- Fix largefile support on older NetBSD systems and OpenBSD by adding
- define for TELL64.
-
-
-Tools and other miscellany
-
-- ftpmirror: Call to main() is wrapped in if __name__ == "__main__".
-
-- freeze: The modulefinder now works with 2.0 opcodes.
-
-- IDLE:
- Move hackery of sys.argv until after the Tk instance has been
- created, which allows the application-specific Tkinter
- initialization to be executed if present; also pass an explicit
- className parameter to the Tk() constructor.
-
-
-What's new in 2.0 beta 1?
-=========================
-
-Source Incompatibilities
-------------------------
-
-None. Note that 1.6 introduced several incompatibilities with 1.5.2,
-such as single-argument append(), connect() and bind(), and changes to
-str(long) and repr(float).
-
-
-Binary Incompatibilities
-------------------------
-
-- Third party extensions built for Python 1.5.x or 1.6 cannot be used
-with Python 2.0; these extensions will have to be rebuilt for Python
-2.0.
-
-- On Windows, attempting to import a third party extension built for
-Python 1.5.x or 1.6 results in an immediate crash; there's not much we
-can do about this. Check your PYTHONPATH environment variable!
-
-- Python bytecode files (*.pyc and *.pyo) are not compatible between
-releases.
-
-
-Overview of Changes Since 1.6
------------------------------
-
-There are many new modules (including brand new XML support through
-the xml package, and i18n support through the gettext module); a list
-of all new modules is included below. Lots of bugs have been fixed.
-
-The process for making major new changes to the language has changed
-since Python 1.6. Enhancements must now be documented by a Python
-Enhancement Proposal (PEP) before they can be accepted.
-
-There are several important syntax enhancements, described in more
-detail below:
-
- - Augmented assignment, e.g. x += 1
-
- - List comprehensions, e.g. [x**2 for x in range(10)]
-
- - Extended import statement, e.g. import Module as Name
-
- - Extended print statement, e.g. print >> file, "Hello"
-
-Other important changes:
-
- - Optional collection of cyclical garbage
-
-Python Enhancement Proposal (PEP)
----------------------------------
-
-PEP stands for Python Enhancement Proposal. A PEP is a design
-document providing information to the Python community, or describing
-a new feature for Python. The PEP should provide a concise technical
-specification of the feature and a rationale for the feature.
-
-We intend PEPs to be the primary mechanisms for proposing new
-features, for collecting community input on an issue, and for
-documenting the design decisions that have gone into Python. The PEP
-author is responsible for building consensus within the community and
-documenting dissenting opinions.
-
-The PEPs are available at http://python.sourceforge.net/peps/.
-
-Augmented Assignment
---------------------
-
-This must have been the most-requested feature of the past years!
-Eleven new assignment operators were added:
-
- += -= *= /= %= **= <<= >>= &= ^= |=
-
-For example,
-
- A += B
-
-is similar to
-
- A = A + B
-
-except that A is evaluated only once (relevant when A is something
-like dict[index].attr).
-
-However, if A is a mutable object, A may be modified in place. Thus,
-if A is a number or a string, A += B has the same effect as A = A+B
-(except A is only evaluated once); but if a is a list, A += B has the
-same effect as A.extend(B)!
-
-Classes and built-in object types can override the new operators in
-order to implement the in-place behavior; the not-in-place behavior is
-used automatically as a fallback when an object doesn't implement the
-in-place behavior. For classes, the method name is derived from the
-method name for the corresponding not-in-place operator by inserting
-an 'i' in front of the name, e.g. __iadd__ implements in-place
-__add__.
-
-Augmented assignment was implemented by Thomas Wouters.
-
-
-List Comprehensions
--------------------
-
-This is a flexible new notation for lists whose elements are computed
-from another list (or lists). The simplest form is:
-
- [<expression> for <variable> in <sequence>]
-
-For example, [i**2 for i in range(4)] yields the list [0, 1, 4, 9].
-This is more efficient than a for loop with a list.append() call.
-
-You can also add a condition:
-
- [<expression> for <variable> in <sequence> if <condition>]
-
-For example, [w for w in words if w == w.lower()] would yield the list
-of words that contain no uppercase characters. This is more efficient
-than a for loop with an if statement and a list.append() call.
-
-You can also have nested for loops and more than one 'if' clause. For
-example, here's a function that flattens a sequence of sequences::
-
- def flatten(seq):
- return [x for subseq in seq for x in subseq]
-
- flatten([[0], [1,2,3], [4,5], [6,7,8,9], []])
-
-This prints
-
- [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
-
-List comprehensions originated as a patch set from Greg Ewing; Skip
-Montanaro and Thomas Wouters also contributed. Described by PEP 202.
-
-
-Extended Import Statement
--------------------------
-
-Many people have asked for a way to import a module under a different
-name. This can be accomplished like this:
-
- import foo
- bar = foo
- del foo
-
-but this common idiom gets old quickly. A simple extension of the
-import statement now allows this to be written as follows:
-
- import foo as bar
-
-There's also a variant for 'from ... import':
-
- from foo import bar as spam
-
-This also works with packages; e.g. you can write this:
-
- import test.regrtest as regrtest
-
-Note that 'as' is not a new keyword -- it is recognized only in this
-context (this is only possible because the syntax for the import
-statement doesn't involve expressions).
-
-Implemented by Thomas Wouters. Described by PEP 221.
-
-
-Extended Print Statement
-------------------------
-
-Easily the most controversial new feature, this extension to the print
-statement adds an option to make the output go to a different file
-than the default sys.stdout.
-
-For example, to write an error message to sys.stderr, you can now
-write:
-
- print >> sys.stderr, "Error: bad dog!"
-
-As a special feature, if the expression used to indicate the file
-evaluates to None, the current value of sys.stdout is used. Thus:
-
- print >> None, "Hello world"
-
-is equivalent to
-
- print "Hello world"
-
-Design and implementation by Barry Warsaw. Described by PEP 214.
-
-
-Optional Collection of Cyclical Garbage
----------------------------------------
-
-Python is now equipped with a garbage collector that can hunt down
-cyclical references between Python objects. It's no replacement for
-reference counting; in fact, it depends on the reference counts being
-correct, and decides that a set of objects belong to a cycle if all
-their reference counts can be accounted for from their references to
-each other. This devious scheme was first proposed by Eric Tiedemann,
-and brought to implementation by Neil Schemenauer.
-
-There's a module "gc" that lets you control some parameters of the
-garbage collection. There's also an option to the configure script
-that lets you enable or disable the garbage collection. In 2.0b1,
-it's on by default, so that we (hopefully) can collect decent user
-experience with this new feature. There are some questions about its
-performance. If it proves to be too much of a problem, we'll turn it
-off by default in the final 2.0 release.
-
-
-Smaller Changes
----------------
-
-A new function zip() was added. zip(seq1, seq2, ...) is equivalent to
-map(None, seq1, seq2, ...) when the sequences have the same length;
-i.e. zip([1,2,3], [10,20,30]) returns [(1,10), (2,20), (3,30)]. When
-the lists are not all the same length, the shortest list wins:
-zip([1,2,3], [10,20]) returns [(1,10), (2,20)]. See PEP 201.
-
-sys.version_info is a tuple (major, minor, micro, level, serial).
-
-Dictionaries have an odd new method, setdefault(key, default).
-dict.setdefault(key, default) returns dict[key] if it exists; if not,
-it sets dict[key] to default and returns that value. Thus:
-
- dict.setdefault(key, []).append(item)
-
-does the same work as this common idiom:
-
- if not dict.has_key(key):
- dict[key] = []
- dict[key].append(item)
-
-There are two new variants of SyntaxError that are raised for
-indentation-related errors: IndentationError and TabError.
-
-Changed \x to consume exactly two hex digits; see PEP 223. Added \U
-escape that consumes exactly eight hex digits.
-
-The limits on the size of expressions and file in Python source code
-have been raised from 2**16 to 2**32. Previous versions of Python
-were limited because the maximum argument size the Python VM accepted
-was 2**16. This limited the size of object constructor expressions,
-e.g. [1,2,3] or {'a':1, 'b':2}, and the size of source files. This
-limit was raised thanks to a patch by Charles Waldman that effectively
-fixes the problem. It is now much more likely that you will be
-limited by available memory than by an arbitrary limit in Python.
-
-The interpreter's maximum recursion depth can be modified by Python
-programs using sys.getrecursionlimit and sys.setrecursionlimit. This
-limit is the maximum number of recursive calls that can be made by
-Python code. The limit exists to prevent infinite recursion from
-overflowing the C stack and causing a core dump. The default value is
-1000. The maximum safe value for a particular platform can be found
-by running Misc/find_recursionlimit.py.
-
-New Modules and Packages
-------------------------
-
-atexit - for registering functions to be called when Python exits.
-
-imputil - Greg Stein's alternative API for writing custom import
-hooks.
-
-pyexpat - an interface to the Expat XML parser, contributed by Paul
-Prescod.
-
-xml - a new package with XML support code organized (so far) in three
-subpackages: xml.dom, xml.sax, and xml.parsers. Describing these
-would fill a volume. There's a special feature whereby a
-user-installed package named _xmlplus overrides the standard
-xmlpackage; this is intended to give the XML SIG a hook to distribute
-backwards-compatible updates to the standard xml package.
-
-webbrowser - a platform-independent API to launch a web browser.
-
-
-Changed Modules
----------------
-
-array -- new methods for array objects: count, extend, index, pop, and
-remove
-
-binascii -- new functions b2a_hex and a2b_hex that convert between
-binary data and its hex representation
-
-calendar -- Many new functions that support features including control
-over which day of the week is the first day, returning strings instead
-of printing them. Also new symbolic constants for days of week,
-e.g. MONDAY, ..., SUNDAY.
-
-cgi -- FieldStorage objects have a getvalue method that works like a
-dictionary's get method and returns the value attribute of the object.
-
-ConfigParser -- The parser object has new methods has_option,
-remove_section, remove_option, set, and write. They allow the module
-to be used for writing config files as well as reading them.
-
-ftplib -- ntransfercmd(), transfercmd(), and retrbinary() all now
-optionally support the RFC 959 REST command.
-
-gzip -- readline and readlines now accept optional size arguments
-
-httplib -- New interfaces and support for HTTP/1.1 by Greg Stein. See
-the module doc strings for details.
-
-locale -- implement getdefaultlocale for Win32 and Macintosh
-
-marshal -- no longer dumps core when marshaling deeply nested or
-recursive data structures
-
-os -- new functions isatty, seteuid, setegid, setreuid, setregid
-
-os/popen2 -- popen2/popen3/popen4 support under Windows. popen2/popen3
-support under Unix.
-
-os/pty -- support for openpty and forkpty
-
-os.path -- fix semantics of os.path.commonprefix
-
-smtplib -- support for sending very long messages
-
-socket -- new function getfqdn()
-
-readline -- new functions to read, write and truncate history files.
-The readline section of the library reference manual contains an
-example.
-
-select -- add interface to poll system call
-
-shutil -- new copyfileobj function
-
-SimpleHTTPServer, CGIHTTPServer -- Fix problems with buffering in the
-HTTP server.
-
-Tkinter -- optimization of function flatten
-
-urllib -- scans environment variables for proxy configuration,
-e.g. http_proxy.
-
-whichdb -- recognizes dumbdbm format
-
-
-Obsolete Modules
-----------------
-
-None. However note that 1.6 made a whole slew of modules obsolete:
-stdwin, soundex, cml, cmpcache, dircache, dump, find, grep, packmail,
-poly, zmod, strop, util, whatsound.
-
-
-Changed, New, Obsolete Tools
-----------------------------
-
-None.
-
-
-C-level Changes
----------------
-
-Several cleanup jobs were carried out throughout the source code.
-
-All C code was converted to ANSI C; we got rid of all uses of the
-Py_PROTO() macro, which makes the header files a lot more readable.
-
-Most of the portability hacks were moved to a new header file,
-pyport.h; several other new header files were added and some old
-header files were removed, in an attempt to create a more rational set
-of header files. (Few of these ever need to be included explicitly;
-they are all included by Python.h.)
-
-Trent Mick ensured portability to 64-bit platforms, under both Linux
-and Win64, especially for the new Intel Itanium processor. Mick also
-added large file support for Linux64 and Win64.
-
-The C APIs to return an object's size have been update to consistently
-use the form PyXXX_Size, e.g. PySequence_Size and PyDict_Size. In
-previous versions, the abstract interfaces used PyXXX_Length and the
-concrete interfaces used PyXXX_Size. The old names,
-e.g. PyObject_Length, are still available for backwards compatibility
-at the API level, but are deprecated.
-
-The PyOS_CheckStack function has been implemented on Windows by
-Fredrik Lundh. It prevents Python from failing with a stack overflow
-on Windows.
-
-The GC changes resulted in creation of two new slots on object,
-tp_traverse and tp_clear. The augmented assignment changes result in
-the creation of a new slot for each in-place operator.
-
-The GC API creates new requirements for container types implemented in
-C extension modules. See Include/objimpl.h for details.
-
-PyErr_Format has been updated to automatically calculate the size of
-the buffer needed to hold the formatted result string. This change
-prevents crashes caused by programmer error.
-
-New C API calls: PyObject_AsFileDescriptor, PyErr_WriteUnraisable.
-
-PyRun_AnyFileEx, PyRun_SimpleFileEx, PyRun_FileEx -- New functions
-that are the same as their non-Ex counterparts except they take an
-extra flag argument that tells them to close the file when done.
-
-XXX There were other API changes that should be fleshed out here.
-
-
-Windows Changes
----------------
-
-New popen2/popen3/peopen4 in os module (see Changed Modules above).
-
-os.popen is much more usable on Windows 95 and 98. See Microsoft
-Knowledge Base article Q150956. The Win9x workaround described there
-is implemented by the new w9xpopen.exe helper in the root of your
-Python installation. Note that Python uses this internally; it is not
-a standalone program.
-
-Administrator privileges are no longer required to install Python
-on Windows NT or Windows 2000. If you have administrator privileges,
-Python's registry info will be written under HKEY_LOCAL_MACHINE.
-Otherwise the installer backs off to writing Python's registry info
-under HKEY_CURRENT_USER. The latter is sufficient for all "normal"
-uses of Python, but will prevent some advanced uses from working
-(for example, running a Python script as an NT service, or possibly
-from CGI).
-
-[This was new in 1.6] The installer no longer runs a separate Tcl/Tk
-installer; instead, it installs the needed Tcl/Tk files directly in the
-Python directory. If you already have a Tcl/Tk installation, this
-wastes some disk space (about 4 Megs) but avoids problems with
-conflicting Tcl/Tk installations, and makes it much easier for Python
-to ensure that Tcl/Tk can find all its files.
-
-[This was new in 1.6] The Windows installer now installs by default in
-\Python20\ on the default volume, instead of \Program Files\Python-2.0\.
-
-
-Updates to the changes between 1.5.2 and 1.6
---------------------------------------------
-
-The 1.6 NEWS file can't be changed after the release is done, so here
-is some late-breaking news:
-
-New APIs in locale.py: normalize(), getdefaultlocale(), resetlocale(),
-and changes to getlocale() and setlocale().
-
-The new module is now enabled per default.
-
-It is not true that the encodings codecs cannot be used for normal
-strings: the string.encode() (which is also present on 8-bit strings
-!) allows using them for 8-bit strings too, e.g. to convert files from
-cp1252 (Windows) to latin-1 or vice-versa.
-
-Japanese codecs are available from Tamito KAJIYAMA:
-http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
-
-
-======================================================================
projects / python / commitdiff