| +++++++++++ |
| Python News |
| +++++++++++ |
| |
| (editors: check NEWS.help for information about editing NEWS using ReST.) |
| |
| What's New in Python 2.3 alpha 1? |
| ================================= |
| |
| *XXX Release date: DD-MMM-2002 XXX* |
| |
| Type/class unification and new-style classes |
| -------------------------------------------- |
| - int() now returns a long object if the argument is outside the |
| integer range, so int("4"*1000), int(1e200) and int(1L<<1000) will |
| all return long objects instead of raising an OverflowError. |
| |
| - Assignment to __class__ is disallowed if either the old or the new |
| class is a statically allocated type object (such as defined by an |
| extension module). This prevents anomalies like 2.__class__ = bool. |
| |
| - New-style object creation and deallocation have been sped up |
| significantly; they are now faster than classic instance creation |
| and deallocation. |
| |
| - The __slots__ variable can now mention "private" names, and the |
| right thing will happen (e.g. __slots__ = ["__foo"]). |
| |
| - The built-ins slice() and buffer() are now callable types. The |
| types classobj (formerly class), code, function, instance, and |
| instancemethod (formerly instance-method), which have no built-in |
| names but are accessible through the types module, are now also |
| callable. The type dict-proxy is renamed to dictproxy. |
| |
| - Cycles going through the __class__ link of a new-style instance are |
| now detected by the garbage collector. |
| |
| - Classes using __slots__ are now properly garbage collected. |
| [SF bug 519621] |
| |
| - Tightened the __slots__ rules: a slot name must be a valid Python |
| identifier. |
| |
| - The constructor for the module type now requires a name argument and |
| takes an optional docstring argument. Previously, this constructor |
| ignored its arguments. As a consequence, deriving a class from a |
| module (not from the module type) is now illegal; previously this |
| created an unnamed module, just like invoking the module type did. |
| [SF bug 563060] |
| |
| - A new type object, 'basestring', is added. This is a common base type |
| for 'str' and 'unicode', and can be used instead of |
| types.StringTypes, e.g. to test whether something is "a string": |
| isinstance(x, basestring) is True for Unicode and 8-bit strings. This |
| is an abstract base class and cannot be instantiated directly. |
| |
| - Changed new-style class instantiation so that when C's __new__ |
| method returns something that's not a C instance, its __init__ is |
| not called. [SF bug #537450] |
| |
| - Fixed super() to work correctly with class methods. [SF bug #535444] |
| |
| - If you try to pickle an instance of a class that has __slots__ but |
| doesn't define or override __getstate__, a TypeError is now raised. |
| This is done by adding a bozo __getstate__ to the class that always |
| raises TypeError. (Before, this would appear to be pickled, but the |
| state of the slots would be lost.) |
| |
| Core and builtins |
| ----------------- |
| |
| - Thanks to Armin Rigo, the last known way to provoke a system crash |
| by cleverly arranging for a comparison function to mutate a list |
| during a list.sort() operation has been fixed. The effect of |
| attempting to mutate a list, or even to inspect its contents or |
| length, while a sort is in progress, is not defined by the language. |
| The C implementation of Python 2.3 attempts to detect mutations, |
| and raise ValueError if one occurs, but there's no guarantee that |
| all mutations will be caught, or that any will be caught across |
| releases or implementations. |
| |
| - Unicode file name processing for Windows (PEP 277) is implemented. |
| All platforms now have an os.path.supports_unicode_filenames attribute, |
| which is set to True on Windows NT/2000/XP, and False elsewhere. |
| |
| - Codec error handling callbacks (PEP 293) are implemented. |
| Error handling in unicode.encode or str.decode can now be customized. |
| |
| - A subtle change to the semantics of the built-in function intern(): |
| interned strings are no longer immortal. You must keep a reference |
| to the return value intern() around to get the benefit. |
| |
| - Use of 'None' as a variable, argument or attribute name now |
| issues a SyntaxWarning. In the future, None may become a keyword. |
| |
| - SET_LINENO is gone. co_lnotab is now consulted to determine when to |
| call the trace function. C code that accessed f_lineno should call |
| PyCode_Addr2Line instead (f_lineno is still there, but not kept up |
| to date). |
| |
| - There's a new warning category, FutureWarning. This is used to warn |
| about a number of situations where the value or sign of an integer |
| result will change in Python 2.4 as a result of PEP 237 (integer |
| unification). The warnings implement stage B0 mentioned in that |
| PEP. The warnings are about the following situations: |
| |
| - Octal and hex literals without 'L' prefix in the inclusive range |
| [0x80000000..0xffffffff]; these are currently negative ints, but |
| in Python 2.4 they will be positive longs with the same bit |
| pattern. |
| |
| - Left shifts on integer values that cause the outcome to lose |
| bits or have a different sign than the left operand. To be |
| precise: x<<n where this currently doesn't yield the same value |
| as long(x)<<n; in Python 2.4, the outcome will be long(x)<<n. |
| |
| - Conversions from ints to string that show negative values as |
| unsigned ints in the inclusive range [0x80000000..0xffffffff]; |
| this affects the functions hex() and oct(), and the string |
| formatting codes %u, %o, %x, and %X. In Python 2.4, these will |
| show signed values (e.g. hex(-1) currently returns "0xffffffff"; |
| in Python 2.4 it will return "-0x1"). |
| |
| - The bits manipulated under the cover by sys.setcheckinterval() have |
| been changed. Both the check interval and the ticker used to be |
| per-thread values. They are now just a pair of global variables. In |
| addition, the default check interval was boosted from 10 to 100 |
| bytecode instructions. This may have some effect on systems that |
| relied on the old default value. In particular, in multi-threaded |
| applications which try to be highly responsive, response time will |
| increase by some (perhaps imperceptible) amount. |
| |
| - When multiplying very large integers, a version of the so-called |
| Karatsuba algorithm is now used. This is most effective if the |
| inputs have roughly the same size. If they both have about N digits, |
| Karatsuba multiplication has O(N**1.58) runtime (the exponent is |
| log_base_2(3)) instead of the previous O(N**2). Measured results may |
| be better or worse than that, depending on platform quirks. Besides |
| the O() improvement in raw instruction count, the Karatsuba algorithm |
| appears to have much better cache behavior on extremely large integers |
| (starting in the ballpark of a million bits). Note that this is a |
| simple implementation, and there's no intent here to compete with, |
| e.g., GMP. It gives a very nice speedup when it applies, but a package |
| devoted to fast large-integer arithmetic should run circles around it. |
| |
| - u'%c' will now raise a ValueError in case the argument is an |
| integer outside the valid range of Unicode code point ordinals. |
| |
| - The tempfile module has been overhauled for enhanced security. The |
| mktemp() function is now deprecated; new, safe replacements are |
| mkstemp() (for files) and mkdtemp() (for directories), and the |
| higher-level functions NamedTemporaryFile() and TemporaryFile(). |
| Use of some global variables in this module is also deprecated; the |
| new functions have keyword arguments to provide the same |
| functionality. All Lib, Tools and Demo modules that used the unsafe |
| interfaces have been updated to use the safe replacements. Thanks |
| to Zack Weinberg! |
| |
| - When x is an object whose class implements __mul__ and __rmul__, |
| 1.0*x would correctly invoke __rmul__, but 1*x would erroneously |
| invoke __mul__. This was due to the sequence-repeat code in the int |
| type. This has been fixed now. |
| |
| - Previously, "str1 in str2" required str1 to be a string of length 1. |
| This restriction has been relaxed to allow str1 to be a string of |
| any length. Thus "'el' in 'hello world'" returns True now. |
| |
| - File objects are now their own iterators. For a file f, iter(f) now |
| returns f (unless f is closed), and f.next() is similar to |
| f.readline() when EOF is not reached; however, f.next() uses a |
| readahead buffer that messes up the file position, so mixing |
| f.next() and f.readline() (or other methods) doesn't work right. |
| Calling f.seek() drops the readahead buffer, but other operations |
| don't. It so happens that this gives a nice additional speed boost |
| to "for line in file:"; the xreadlines method and corresponding |
| module are now obsolete. Thanks to Oren Tirosh! |
| |
| - Encoding declarations (PEP 263, phase 1) have been implemented. A |
| comment of the form "# -*- coding: <encodingname> -*-" in the first |
| or second line of a Python source file indicates the encoding. |
| |
| - list.sort() has a new implementation. While cross-platform results |
| may vary, and in data-dependent ways, this is much faster on many |
| kinds of partially ordered lists than the previous implementation, |
| and reported to be just as fast on randomly ordered lists on |
| several major platforms. This sort is also stable (if A==B and A |
| precedes B in the list at the start, A precedes B after the sort too), |
| although the language definition does not guarantee stability. A |
| potential drawback is that list.sort() may require temp space of |
| len(list)*2 bytes (``*4`` on a 64-bit machine). It's therefore possible |
| for list.sort() to raise MemoryError now, even if a comparison function |
| does not. See <http://www.python.org/sf/587076> for full details. |
| |
| - All standard iterators now ensure that, once StopIteration has been |
| raised, all future calls to next() on the same iterator will also |
| raise StopIteration. There used to be various counterexamples to |
| this behavior, which could caused confusion or subtle program |
| breakage, without any benefits. (Note that this is still an |
| iterator's responsibility; the iterator framework does not enforce |
| this.) |
| |
| - Ctrl+C handling on Windows has been made more consistent with |
| other platforms. KeyboardInterrupt can now reliably be caught, |
| and Ctrl+C at an interactive prompt no longer terminates the |
| process under NT/2k/XP (it never did under Win9x). Ctrl+C will |
| interrupt time.sleep() in the main thread, and any child processes |
| created via the popen family (on win2k; we can't make win9x work |
| reliably) are also interrupted (as generally happens on for Linux/Unix.) |
| [SF bugs 231273, 439992 and 581232] |
| |
| - sys.getwindowsversion() has been added on Windows. This |
| returns a tuple with information about the version of Windows |
| currently running. |
| |
| - Slices and repetitions of buffer objects now consistently return |
| a string. Formerly, strings would be returned most of the time, |
| but a buffer object would be returned when the repetition count |
| was one or when the slice range was all inclusive. |
| |
| - Unicode objects in sys.path are no longer ignored but treated |
| as directory names. |
| |
| - Fixed string.startswith and string.endswith builtin methods |
| so they accept negative indices. [SF bug 493951] |
| |
| - Fixed a bug with a continue inside a try block and a yield in the |
| finally clause. [SF bug 567538] |
| |
| - Most builtin sequences now support "extended slices", i.e. slices |
| with a third "stride" parameter. For example, "hello world"[::-1] |
| gives "dlrow olleh". |
| |
| - A new warning PendingDeprecationWarning was added to provide |
| direction on features which are in the process of being deprecated. |
| The warning will not be printed by default. To see the pending |
| deprecations, use -Walways::PendingDeprecationWarning:: |
| as a command line option or warnings.filterwarnings() in code. |
| |
| - Deprecated features of xrange objects have been removed as |
| promised. The start, stop, and step attributes and the tolist() |
| method no longer exist. xrange repetition and slicing have been |
| removed. |
| |
| - New builtin function enumerate(x), from PEP 279. Example: |
| enumerate("abc") is an iterator returning (0,"a"), (1,"b"), (2,"c"). |
| The argument can be an arbitrary iterable object. |
| |
| - The assert statement no longer tests __debug__ at runtime. This means |
| that assert statements cannot be disabled by assigning a false value |
| to __debug__. |
| |
| - A method zfill() was added to str and unicode, that fills a numeric |
| string to the left with zeros. For example, |
| "+123".zfill(6) -> "+00123". |
| |
| - Complex numbers supported divmod() and the // and % operators, but |
| these make no sense. Since this was documented, they're being |
| deprecated now. |
| |
| - String and unicode methods lstrip(), rstrip() and strip() now take |
| an optional argument that specifies the characters to strip. For |
| example, "Foo!!!?!?!?".rstrip("?!") -> "Foo". |
| |
| - Added a new dict method pop(key). This removes and returns the |
| value corresponding to key. [SF patch #539949] |
| |
| - A new built-in type, bool, has been added, as well as built-in |
| names for its two values, True and False. Comparisons and sundry |
| other operations that return a truth value have been changed to |
| return a bool instead. Read PEP 285 for an explanation of why this |
| is backward compatible. |
| |
| - Fixed two bugs reported as SF #535905: under certain conditions, |
| deallocating a deeply nested structure could cause a segfault in the |
| garbage collector, due to interaction with the "trashcan" code; |
| access to the current frame during destruction of a local variable |
| could access a pointer to freed memory. |
| |
| - The optional object allocator ("pymalloc") has been enabled by |
| default. The recommended practice for memory allocation and |
| deallocation has been streamlined. A header file is included, |
| Misc/pymemcompat.h, which can be bundled with 3rd party extensions |
| and lets them use the same API with Python versions from 1.5.2 |
| onwards. |
| |
| - PyErr_Display will provide file and line information for all exceptions |
| that have an attribute print_file_and_line, not just SyntaxErrors. |
| |
| - The UTF-8 codec will now encode and decode Unicode surrogates |
| correctly and without raising exceptions for unpaired ones. |
| |
| - Universal newlines (PEP 278) is implemented. Briefly, using 'U' |
| instead of 'r' when opening a text file for reading changes the line |
| ending convention so that any of '\r', '\r\n', and '\n' is |
| recognized (even mixed in one file); all three are converted to |
| '\n', the standard Python line end character. |
| |
| - file.xreadlines() now raises a ValueError if the file is closed: |
| Previously, an xreadlines object was returned which would raise |
| a ValueError when the xreadlines.next() method was called. |
| |
| - sys.exit() inadvertently allowed more than one argument. |
| An exception will now be raised if more than one argument is used. |
| |
| Extension modules |
| ----------------- |
| |
| - The PyBSDDB wrapper around the Sleepycat Berkely DB library has been |
| added as the package bsddb. The traditional bsddb module is still |
| available in source code, but not built automatically anymore, and |
| is now named bsddb185. |
| |
| - resource.getrlimit() now returns longs instead of ints. |
| |
| - readline now dynamically adjusts its input/output stream if |
| sys.stdin/stdout changes. |
| |
| - The _tkinter module (and hence Tkinter) has dropped support for |
| Tcl/Tk 8.0 and 8.1. Only Tcl/Tk versions 8.2, 8.3 and 8.4 are |
| supported. |
| |
| - cPickle.BadPickleGet is now a class. |
| |
| - The time stamps in os.stat_result are floating point numbers |
| after stat_float_times has been called. |
| |
| - If the size passed to mmap.mmap() is larger than the length of the |
| file on non-Windows platforms, a ValueError is raised. [SF bug 585792] |
| |
| - The xreadlines module is slated for obsolescence. |
| |
| - The strptime function in the time module is now always available (a |
| Python implementation is used when the C library doesn't define it). |
| |
| - The 'new' module is no longer an extension, but a Python module that |
| only exists for backwards compatibility. Its contents are no longer |
| functions but callable type objects. |
| |
| - The bsddb.*open functions can now take 'None' as a filename. |
| This will create a temporary in-memory bsddb that won't be |
| written to disk. |
| |
| - posix.lchown, posix.killpg, posix.mknod, and posix.getpgid have been |
| added where available. |
| |
| - The locale module now exposes the C library's gettext interface. It |
| also has a new function getpreferredencoding. |
| |
| - A security hole ("double free") was found in zlib-1.1.3, a popular |
| third party compression library used by some Python modules. The |
| hole was quickly plugged in zlib-1.1.4, and the Windows build of |
| Python now ships with zlib-1.1.4. |
| |
| - pwd, grp, and resource return enhanced tuples now, with symbolic |
| field names. |
| |
| - array.array is now a type object. A new format character |
| 'u' indicates Py_UNICODE arrays. For those, .tounicode and |
| .fromunicode methods are available. Arrays now support __iadd__ |
| and __imul__. |
| |
| - dl now builds on every system that has dlfcn.h. Failure in case |
| of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open |
| is called. |
| |
| - signal.sigpending, signal.sigprocmask and signal.sigsuspend have |
| been added where available. |
| |
| - The sys module acquired a new attribute, api_version, which evaluates |
| to the value of the PYTHON_API_VERSION macro with which the |
| interpreter was compiled. |
| |
| - Fixed bug #470582: sre module would return a tuple (None, 'a', 'ab') |
| when applying the regular expression '^((a)c)?(ab)$' on 'ab'. It now |
| returns (None, None, 'ab'), as expected. Also fixed handling of |
| lastindex/lastgroup match attributes in similar cases. For example, |
| when running the expression r'(a)(b)?b' over 'ab', lastindex must be |
| 1, not 2. |
| |
| - Fixed bug #581080: sre scanner was not checking the buffer limit |
| before increasing the current pointer. This was creating an infinite |
| loop in the search function, once the pointer exceeded the buffer |
| limit. |
| |
| - The os.fdopen function now enforces a file mode starting with the |
| letter 'r', 'w' or 'a', otherwise a ValueError is raised. This fixes |
| bug #623464. |
| |
| Library |
| ------- |
| |
| - A new module, optparse, provides a fancy alternative to getopt for |
| command line parsing. It is a slightly modified version of Greg |
| Ward's Optik package. |
| |
| - UserDict.py now defines a DictMixin class which defines all dictionary |
| methods for classes that already have a minimum mapping interface. |
| This greatly simplifies writing classes that need to be substitutable |
| for dictionaries (such as the shelve module). |
| |
| - shelve.py now subclasses from UserDict.DictMixin. Now shelve supports |
| all dictionary methods. This eases the transition to persistent |
| storage for scripts originally written with dictionaries in mind. |
| |
| - A new package, logging, implements the logging API defined by PEP |
| 282. The code is written by Vinay Sajip. |
| |
| - StreamReader, StreamReaderWriter and StreamRecoder in the codecs |
| modules are iterators now. |
| |
| - gzip.py now handles files exceeding 2GB. Files over 4GB also work |
| now (provided the OS supports it, and Python is configured with large |
| file support), but in that case the underlying gzip file format can |
| record only the least-significant 32 bits of the file size, so that |
| some tools working with gzipped files may report an incorrect file |
| size. |
| |
| - xml.sax.saxutils.unescape has been added, to replace entity references |
| with their entity value. |
| |
| - Queue.Queue.{put,get} now support an optional timeout argument. |
| |
| - Various features of Tk 8.4 are exposed in Tkinter.py. The multiple |
| option of tkFileDialog is exposed as function askopenfile{,name}s. |
| |
| - Various configure methods of Tkinter have been stream-lined, so that |
| tag_configure, image_configure, window_configure now return a |
| dictionary when invoked with no argument. |
| |
| - Importing the readline module now no longer has the side effect of |
| calling setlocale(LC_CTYPE, ""). The initial "C" locale, or |
| whatever locale is explicitly set by the user, is preserved. If you |
| want repr() of 8-bit strings in your preferred encoding to preserve |
| all printable characters of that encoding, you have to add the |
| following code to your $PYTHONSTARTUP file or to your application's |
| main(): |
| |
| import locale |
| locale.setlocale(locale.LC_CTYPE, "") |
| |
| - shutil.move was added. shutil.copytree now reports errors as an |
| exception at the end, instead of printing error messages. |
| |
| - Encoding name normalization was generalized to not only |
| replace hyphens with underscores, but also all other non-alphanumeric |
| characters (with the exception of the dot which is used for Python |
| package names during lookup). The aliases.py mapping was updated |
| to the new standard. |
| |
| - mimetypes has two new functions: guess_all_extensions() which |
| returns a list of all known extensions for a mime type, and |
| add_type() which adds one mapping between a mime type and |
| an extension to the database. |
| |
| - New module: sets, defines the class Set that implements a mutable |
| set type using the keys of a dict to represent the set. There's |
| also a class ImmutableSet which is useful when you need sets of sets |
| or when you need to use sets as dict keys, and a class BaseSet which |
| is the base class of the two. (This is not documented yet, but |
| help(sets) gives a wealth of information.) |
| |
| - Added operator.pow(a,b) which is equivalent to a**b. |
| |
| - Added random.sample(population,k) for random sampling without replacement. |
| Returns a k length list of unique elements chosen from the population. |
| |
| - random.randrange(-sys.maxint-1, sys.maxint) no longer raises |
| OverflowError. That is, it now accepts any combination of 'start' |
| and 'stop' arguments so long as each is in the range of Python's |
| bounded integers. |
| |
| - New "algorithms" module: heapq, implements a heap queue. Thanks to |
| Kevin O'Connor for the code and François Pinard for an entertaining |
| write-up explaining the theory and practical uses of heaps. |
| |
| - New encoding for the Palm OS character set: palmos. |
| |
| - binascii.crc32() and the zipfile module had problems on some 64-bit |
| platforms. These have been fixed. On a platform with 8-byte C longs, |
| crc32() now returns a signed-extended 4-byte result, so that its value |
| as a Python int is equal to the value computed a 32-bit platform. |
| |
| - xml.dom.minidom.toxml and toprettyxml now take an optional encoding |
| argument. |
| |
| - Some fixes in the copy module: when an object is copied through its |
| __reduce__ method, there was no check for a __setstate__ method on |
| the result [SF patch 565085]; deepcopy should treat instances of |
| custom metaclasses the same way it treats instances of type 'type' |
| [SF patch 560794]. |
| |
| - Sockets now support timeout mode. After s.settimeout(T), where T is |
| a float expressing seconds, subsequent operations raise an exception |
| if they cannot be completed within T seconds. To disable timeout |
| mode, use s.settimeout(None). There's also a module function, |
| socket.setdefaulttimeout(T), which sets the default for all sockets |
| created henceforth. |
| |
| - getopt.gnu_getopt was added. This supports GNU-style option |
| processing, where options can be mixed with non-option arguments. |
| |
| - Stop using strings for exceptions. String objects used for |
| exceptions are now classes deriving from Exception. The objects |
| changed were: Tkinter.TclError, bdb.BdbQuit, macpath.norm_error, |
| tabnanny.NannyNag, and xdrlib.Error. |
| |
| - Constants BOM_UTF8, BOM_UTF16, BOM_UTF16_LE, BOM_UTF16_BE, |
| BOM_UTF32, BOM_UTF32_LE and BOM_UTF32_BE that represent the Byte |
| Order Mark in UTF-8, UTF-16 and UTF-32 encodings for little and |
| big endian systems were added to the codecs module. The old names |
| BOM32_* and BOM64_* were off by a factor of 2. |
| |
| - Added conversion functions math.degrees() and math.radians(). |
| |
| - ftplib.retrlines() now tests for callback is None rather than testing |
| for False. Was causing an error when given a callback object which |
| was callable but also returned len() as zero. The change may |
| create new breakage if the caller relied on the undocumented behavior |
| and called with callback set to [] or some other False value not |
| identical to None. |
| |
| - random.gauss() uses a piece of hidden state used by nothing else, |
| and the .seed() and .whseed() methods failed to reset it. In other |
| words, setting the seed didn't completely determine the sequence of |
| results produced by random.gauss(). It does now. Programs repeatedly |
| mixing calls to a seed method with calls to gauss() may see different |
| results now. |
| |
| - The pickle.Pickler class grew a clear_memo() method to mimic that |
| provided by cPickle.Pickler. |
| |
| - difflib's SequenceMatcher class now does a dynamic analysis of |
| which elements are so frequent as to constitute noise. For |
| comparing files as sequences of lines, this generally works better |
| than the IS_LINE_JUNK function, and function ndiff's linejunk |
| argument defaults to None now as a result. A happy benefit is |
| that SequenceMatcher may run much faster now when applied |
| to large files with many duplicate lines (for example, C program |
| text with lots of repeated "}" and "return NULL;" lines). |
| |
| - New Text.dump() method in Tkinter module. |
| |
| - New distutils commands for building packagers were added to |
| support pkgtool on Solaris and swinstall on HP-UX. |
| |
| - distutils now has a new abstract binary packager base class |
| command/bdist_packager, which simplifies writing packagers. |
| This will hopefully provide the missing bits to encourage |
| people to submit more packagers, e.g. for Debian, FreeBSD |
| and other systems. |
| |
| - The UTF-16, -LE and -BE stream readers now raise a |
| NotImplementedError for all calls to .readline(). Previously, they |
| used to just produce garbage or fail with an encoding error -- |
| UTF-16 is a 2-byte encoding and the C lib's line reading APIs don't |
| work well with these. |
| |
| - compileall now supports quiet operation. |
| |
| - The BaseHTTPServer now implements optional HTTP/1.1 persistent |
| connections. |
| |
| - socket module: the SSL support was broken out of the main |
| _socket module C helper and placed into a new _ssl helper |
| which now gets imported by socket.py if available and working. |
| |
| - encodings package: added aliases for all supported IANA character |
| sets |
| |
| - ftplib: to safeguard the user's privacy, anonymous login will use |
| "anonymous@" as default password, rather than the real user and host |
| name. |
| |
| - webbrowser: tightened up the command passed to os.system() so that |
| arbitrary shell code can't be executed because a bogus URL was |
| passed in. |
| |
| - gettext.translation has an optional fallback argument, and |
| gettext.find an optional all argument. Translations will now fallback |
| on a per-message basis. The module supports plural forms, by means |
| of gettext.[d]ngettext and Translation.[u]ngettext. |
| |
| - distutils bdist commands now offer a --skip-build option. |
| |
| - warnings.warn now accepts a Warning instance as first argument. |
| |
| - The xml.sax.expatreader.ExpatParser class will no longer create |
| circular references by using itself as the locator that gets passed |
| to the content handler implementation. [SF bug #535474] |
| |
| - The email.Parser.Parser class now properly parses strings regardless |
| of their line endings, which can be any of \r, \n, or \r\n (CR, LF, |
| or CRLF). Also, the Header class's constructor default arguments |
| has changed slightly so that an explicit maxlinelen value is always |
| honored. |
| |
| - distutils' build_ext command now links c++ extensions with the c++ |
| compiler available in the Makefile or CXX environment variable, if |
| running under *nix. |
| |
| - New module bz2: provides a comprehensive interface for the bz2 compression |
| library. It implements a complete file interface, one-shot (de)compression |
| functions, and types for sequential (de)compression. |
| |
| - New pdb command `pp' which is like `p' except that it pretty-prints |
| the value of its expression argument. |
| |
| - Now bdist_rpm distutils command understands a verify_script option in |
| the config file, including the contents of the referred filename in |
| the "%verifyscript" section of the rpm spec file. |
| |
| Tools/Demos |
| ----------- |
| |
| - The SGI demos (Demo/sgi) have been removed. Nobody thought they |
| were interesting any more. (The SGI library modules and extensions |
| are still there; it is believed that at least some of these are |
| still used and useful.) |
| |
| - IDLE supports the new encoding declarations (PEP 263); it can also |
| deal with legacy 8-bit files if they use the locale's encoding. It |
| allows non-ASCII strings in the interactive shell and executes them |
| in the locale's encoding. |
| |
| - freeze.py now produces binaries which can import shared modules, |
| unlike before when this failed due to missing symbol exports in |
| the generated binary. |
| |
| Build |
| ----- |
| |
| - On Unix, IDLE is now installed automatically. |
| |
| - The fpectl module is not built by default; it's dangerous or useless |
| except in the hands of experts. |
| |
| - The public Python C API will generally be declared using PyAPI_FUNC |
| and PyAPI_DATA macros, while Python extension module init functions |
| will be declared with PyMODINIT_FUNC. DL_EXPORT/DL_IMPORT macros |
| are deprecated. |
| |
| - A bug was fixed that could cause COUNT_ALLOCS builds to segfault, or |
| get into infinite loops, when a new-style class got garbage-collected. |
| Unfortunately, to avoid this, the way COUNT_ALLOCS works requires |
| that new-style classes be immortal in COUNT_ALLOCS builds. Note that |
| COUNT_ALLOCS is not enabled by default, in either release or debug |
| builds, and that new-style classes are immortal only in COUNT_ALLOCS |
| builds. |
| |
| - Compiling out the cyclic garbage collector is no longer an option. |
| The old symbol WITH_CYCLE_GC is now ignored, and Python.h arranges |
| that it's always defined (for the benefit of any extension modules |
| that may be conditionalizing on it). A bonus is that any extension |
| type participating in cyclic gc can choose to participate in the |
| Py_TRASHCAN mechanism now too; in the absence of cyclic gc, this used |
| to require editing the core to teach the trashcan mechanism about the |
| new type. |
| |
| - According to Annex F of the current C standard, |
| |
| The Standard C macro HUGE_VAL and its float and long double analogs, |
| HUGE_VALF and HUGE_VALL, expand to expressions whose values are |
| positive infinities. |
| |
| Python only uses the double HUGE_VAL, and only to #define its own symbol |
| Py_HUGE_VAL. Some platforms have incorrect definitions for HUGE_VAL. |
| pyport.h used to try to worm around that, but the workarounds triggered |
| other bugs on other platforms, so we gave up. If your platform defines |
| HUGE_VAL incorrectly, you'll need to #define Py_HUGE_VAL to something |
| that works on your platform. The only instance of this I'm sure about |
| is on an unknown subset of Cray systems, described here: |
| |
| http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm |
| |
| Presumably 2.3a1 breaks such systems. If anyone uses such a system, help! |
| |
| - The configure option --without-doc-strings can be used to remove the |
| doc strings from the builtin functions and modules; this reduces the |
| size of the executable. |
| |
| - The universal newlines option (PEP 278) is on by default. On Unix |
| it can be disabled by passing --without-universal-newlines to the |
| configure script. On other platforms, remove |
| WITH_UNIVERSAL_NEWLINES from pyconfig.h. |
| |
| - On Unix, a shared libpython2.3.so can be created with --enable-shared. |
| |
| - All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS |
| preprocessor symbols were eliminated. The internal decisions they |
| controlled stopped being experimental long ago. |
| |
| - The tools used to build the documentation now work under Cygwin as |
| well as Unix. |
| |
| - The bsddb and dbm module builds have been changed to try and avoid version |
| skew problems and disable linkage with Berkeley DB 1.85 unless the |
| installer knows what s/he's doing. See the section on building these |
| modules in the README file for details. |
| |
| C API |
| ----- |
| |
| - PyNumber_Check() now returns true for string and unicode objects. |
| This is a result of these types having a partially defined |
| tp_as_number slot. (This is not a feature, but an indication that |
| PyNumber_Check() is not very useful to determine numeric behavior. |
| It may be deprecated.) |
| |
| - The string object's layout has changed: the pointer member |
| ob_sinterned has been replaced by an int member ob_sstate. On some |
| platforms (e.g. most 64-bit systems) this may change the offset of |
| the ob_sval member, so as a precaution the API_VERSION has been |
| incremented. The apparently unused feature of "indirect interned |
| strings", supported by the ob_sinterned member, is gone. Interned |
| strings are now usually mortal; theres a new API, |
| PyString_InternImmortal() that creates immortal interned strings. |
| (The ob_sstate member can only take three values; however, while |
| making it a char saves a few bytes per string object on average, in |
| it also slowed things down a bit because ob_sval was no longer |
| aligned.) |
| |
| - The Py_InitModule*() functions now accept NULL for the 'methods' |
| argument. Modules without global functions are becoming more common |
| now that factories can be types rather than functions. |
| |
| - New C API PyUnicode_FromOrdinal() which exposes unichr() at C |
| level. |
| |
| - New functions PyErr_SetExcFromWindowsErr() and |
| PyErr_SetExcFromWindowsErrWithFilename(). Similar to |
| PyErr_SetFromWindowsErrWithFilename() and |
| PyErr_SetFromWindowsErr(), but they allow to specify |
| the exception type to raise. Available on Windows. |
| |
| - Py_FatalError() is now declared as taking a const char* argument. It |
| was previously declared without const. This should not affect working |
| code. |
| |
| - Added new macro PySequence_ITEM(o, i) that directly calls |
| sq_item without rechecking that o is a sequence and without |
| adjusting for negative indices. |
| |
| - PyRange_New() now raises ValueError if the fourth argument is not 1. |
| This is part of the removal of deprecated features of the xrange |
| object. |
| |
| - PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's |
| coercion if both arguments have the same type but this type has the |
| CHECKTYPES flag set. This is to better support proxies. |
| |
| - The type of tp_free has been changed from "``void (*)(PyObject *)``" to |
| "``void (*)(void *)``". |
| |
| - PyObject_Del, PyObject_GC_Del are now functions instead of macros. |
| |
| - A type can now inherit its metatype from its base type. Previously, |
| when PyType_Ready() was called, if ob_type was found to be NULL, it |
| was always set to &PyType_Type; now it is set to base->ob_type, |
| where base is tp_base, defaulting to &PyObject_Type. |
| |
| - PyType_Ready() accidentally did not inherit tp_is_gc; now it does. |
| |
| - The PyCore_* family of APIs have been removed. |
| |
| - The "u#" parser marker will now pass through Unicode objects as-is |
| without going through the buffer API. |
| |
| - The enumerators of cmp_op have been renamed to use the prefix ``PyCmp_``. |
| |
| - An old #define of ANY as void has been removed from pyport.h. This |
| hasn't been used since Python's pre-ANSI days, and the #define has |
| been marked as obsolete since then. SF bug 495548 says it created |
| conflicts with other packages, so keeping it around wasn't harmless. |
| |
| - Because Python's magic number scheme broke on January 1st, we decided |
| to stop Python development. Thanks for all the fish! |
| |
| - Some of us don't like fish, so we changed Python's magic number |
| scheme to a new one. See Python/import.c for details. |
| |
| New platforms |
| ------------- |
| |
| - AtheOS is now supported. |
| |
| - the EMX runtime environment on OS/2 is now supported. |
| |
| - GNU/Hurd is now supported. |
| |
| Tests |
| ----- |
| |
| Yet to be written. |
| |
| Windows |
| ------- |
| |
| - The Windows distribution now ships with Tcl/Tk version 8.4.1 (it |
| previously shipped with Tcl/Tk 8.3.2). |
| |
| - When Python is built under a Microsoft compiler, sys.version now |
| includes the compiler version number (_MSC_VER). For example, under |
| MSVC 6, sys.version constains the substring "MSC v.1200 ". 1200 is |
| the value of _MSC_VER under MSVC 6. |
| |
| - Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause |
| of that has been fixed in the installer (disabled Wise's "delete in- |
| use files" uninstall option). |
| |
| - Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031] |
| |
| - The installer now installs Start menu shortcuts under (the local |
| equivalent of) "All Users" when doing an Admin install. |
| |
| - file.truncate([newsize]) now works on Windows for all newsize values. |
| It used to fail if newsize didn't fit in 32 bits, reflecting a |
| limitation of MS _chsize (which is no longer used). |
| |
| - os.waitpid() is now implemented for Windows, and can be used to block |
| until a specified process exits. This is similar to, but not exactly |
| the same as, os.waitpid() on POSIX systems. If you're waiting for |
| a specific process whose pid was obtained from one of the spawn() |
| functions, the same Python os.waitpid() code works across platforms. |
| See the docs for details. The docs were changed to clarify that |
| spawn functions return, and waitpid requires, a process handle on |
| Windows (not the same thing as a Windows process id). |
| |
| - New tempfile.TemporaryFile implementation for Windows: this doesn't |
| need a TemporaryFileWrapper wrapper anymore, and should be immune |
| to a nasty problem: before 2.3, if you got a temp file on Windows, it |
| got wrapped in an object whose close() method first closed the |
| underlying file, then deleted the file. This usually worked fine. |
| However, the spawn family of functions on Windows create (at a low C |
| level) the same set of open files in the spawned process Q as were |
| open in the spawning process P. If a temp file f was among them, then |
| doing f.close() in P first closed P's C-level file handle on f, but Q's |
| C-level file handle on f remained open, so the attempt in P to delete f |
| blew up with a "Permission denied" error (Windows doesn't allow |
| deleting open files). This was surprising, subtle, and difficult to |
| work around. |
| |
| - The os module now exports all the symbolic constants usable with the |
| low-level os.open() on Windows: the new constants in 2.3 are |
| O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL. |
| The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT, |
| O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary |
| to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY |
| (so specify both if you want both; note that neither is useful unless |
| specified with O_CREAT too). |
| |
| Mac |
| ---- |
| |
| Yet to be written. |
| |
| |
| What's New in Python 2.2 final? |
| =============================== |
| |
| *Release date: 21-Dec-2001* |
| |
| Type/class unification and new-style classes |
| -------------------------------------------- |
| |
| - pickle.py, cPickle: allow pickling instances of new-style classes |
| with a custom metaclass. |
| |
| Core and builtins |
| ----------------- |
| |
| - weakref proxy object: when comparing, unwrap both arguments if both |
| are proxies. |
| |
| Extension modules |
| ----------------- |
| |
| - binascii.b2a_base64(): fix a potential buffer overrun when encoding |
| very short strings. |
| |
| - cPickle: the obscure "fast" mode was suspected of causing stack |
| overflows on the Mac. Hopefully fixed this by setting the recursion |
| limit much smaller. If the limit is too low (it only affects |
| performance), you can change it by defining PY_CPICKLE_FAST_LIMIT |
| when compiling cPickle.c (or in pyconfig.h). |
| |
| Library |
| ------- |
| |
| - dumbdbm.py: fixed a dumb old bug (the file didn't get synched at |
| close or delete time). |
| |
| - rfc822.py: fixed a bug where the address '<>' was converted to None |
| instead of an empty string (also fixes the email.Utils module). |
| |
| - xmlrpclib.py: version 1.0.0; uses precision for doubles. |
| |
| - test suite: the pickle and cPickle tests were not executing any code |
| when run from the standard regression test. |
| |
| Tools/Demos |
| ----------- |
| |
| Build |
| ----- |
| |
| C API |
| ----- |
| |
| New platforms |
| ------------- |
| |
| Tests |
| ----- |
| |
| Windows |
| ------- |
| |
| - distutils package: fixed broken Windows installers (bdist_wininst). |
| |
| - tempfile.py: prevent mysterious warnings when TemporaryFileWrapper |
| instances are deleted at process exit time. |
| |
| - socket.py: prevent mysterious warnings when socket instances are |
| deleted at process exit time. |
| |
| - posixmodule.c: fix a Windows crash with stat() of a filename ending |
| in backslash. |
| |
| Mac |
| ---- |
| |
| - The Carbon toolbox modules have been upgraded to Universal Headers |
| 3.4, and experimental CoreGraphics and CarbonEvents modules have |
| been added. All only for framework-enabled MacOSX. |
| |
| |
| What's New in Python 2.2c1? |
| =========================== |
| |
| *Release date: 14-Dec-2001* |
| |
| Type/class unification and new-style classes |
| -------------------------------------------- |
| |
| - Guido's tutorial introduction to the new type/class features has |
| been extensively updated. See |
| |
| http://www.python.org/2.2/descrintro.html |
| |
| That remains the primary documentation in this area. |
| |
| - Fixed a leak: instance variables declared with __slots__ were never |
| deleted! |
| |
| - The "delete attribute" method of descriptor objects is called |
| __delete__, not __del__. In previous releases, it was mistakenly |
| called __del__, which created an unfortunate overloading condition |
| with finalizers. (The "get attribute" and "set attribute" methods |
| are still called __get__ and __set__, respectively.) |
| |
| - Some subtle issues with the super built-in were fixed: |
| |
| (a) When super itself is subclassed, its __get__ method would still |
| return an instance of the base class (i.e., of super). |
| |
| (b) super(C, C()).__class__ would return C rather than super. This |
| is confusing. To fix this, I decided to change the semantics of |
| super so that it only applies to code attributes, not to data |
| attributes. After all, overriding data attributes is not |
| supported anyway. |
| |
| (c) The __get__ method didn't check whether the argument was an |
| instance of the type used in creation of the super instance. |
| |
| - Previously, hash() of an instance of a subclass of a mutable type |
| (list or dictionary) would return some value, rather than raising |
| TypeError. This has been fixed. Also, directly calling |
| dict.__hash__ and list.__hash__ now raises the same TypeError |
| (previously, these were the same as object.__hash__). |
| |
| - New-style objects now support deleting their __dict__. This is for |
| all intents and purposes equivalent to assigning a brand new empty |
| dictionary, but saves space if the object is not used further. |
| |
| Core and builtins |
| ----------------- |
| |
| - -Qnew now works as documented in PEP 238: when -Qnew is passed on |
| the command line, all occurrences of "/" use true division instead |
| of classic division. See the PEP for details. Note that "all" |
| means all instances in library and 3rd-party modules, as well as in |
| your own code. As the PEP says, -Qnew is intended for use only in |
| educational environments with control over the libraries in use. |
| Note that test_coercion.py in the standard Python test suite fails |
| under -Qnew; this is expected, and won't be repaired until true |
| division becomes the default (in the meantime, test_coercion is |
| testing the current rules). |
| |
| - complex() now only allows the first argument to be a string |
| argument, and raises TypeError if either the second arg is a string |
| or if the second arg is specified when the first is a string. |
| |
| Extension modules |
| ----------------- |
| |
| - gc.get_referents was renamed to gc.get_referrers. |
| |
| Library |
| ------- |
| |
| - Functions in the os.spawn() family now release the global interpreter |
| lock around calling the platform spawn. They should always have done |
| this, but did not before 2.2c1. Multithreaded programs calling |
| an os.spawn function with P_WAIT will no longer block all Python threads |
| until the spawned program completes. It's possible that some programs |
| relies on blocking, although more likely by accident than by design. |
| |
| - webbrowser defaults to netscape.exe on OS/2 now. |
| |
| - Tix.ResizeHandle exposes detach_widget, hide, and show. |
| |
| - The charset alias windows_1252 has been added. |
| |
| - types.StringTypes is a tuple containing the defined string types; |
| usually this will be (str, unicode), but if Python was compiled |
| without Unicode support it will be just (str,). |
| |
| - The pulldom and minidom modules were synchronized to PyXML. |
| |
| Tools/Demos |
| ----------- |
| |
| - A new script called Tools/scripts/google.py was added, which fires |
| off a search on Google. |
| |
| Build |
| ----- |
| |
| - Note that release builds of Python should arrange to define the |
| preprocessor symbol NDEBUG on the command line (or equivalent). |
| In the 2.2 pre-release series we tried to define this by magic in |
| Python.h instead, but it proved to cause problems for extension |
| authors. The Unix, Windows and Mac builds now all define NDEBUG in |
| release builds via cmdline (or equivalent) instead. Ports to |
| other platforms should do likewise. |
| |
| - It is no longer necessary to use --with-suffix when building on a |
| case-insensitive file system (such as Mac OS X HFS+). In the build |
| directory an extension is used, but not in the installed python. |
| |
| C API |
| ----- |
| |
| - New function PyDict_MergeFromSeq2() exposes the builtin dict |
| constructor's logic for updating a dictionary from an iterable object |
| producing key-value pairs. |
| |
| - PyArg_ParseTupleAndKeywords() requires that the number of entries in |
| the keyword list equal the number of argument specifiers. This |
| wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even |
| dump core in some bad cases. This has been repaired. As a result, |
| PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that |
| previously went unchallenged. |
| |
| New platforms |
| ------------- |
| |
| Tests |
| ----- |
| |
| Windows |
| ------- |
| |
| Mac |
| ---- |
| |
| - In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin", |
| without any trailing digits. |
| |
| - Changed logic for finding python home in Mac OS X framework Pythons. |
| Now sys.executable points to the executable again, in stead of to |
| the shared library. The latter is used only for locating the python |
| home. |
| |
| |
| What's New in Python 2.2b2? |
| =========================== |
| |
| *Release date: 16-Nov-2001* |
| |
| Type/class unification and new-style classes |
| -------------------------------------------- |
| |
| - Multiple inheritance mixing new-style and classic classes in the |
| list of base classes is now allowed, so this works now: |
| |
| class Classic: pass |
| class Mixed(Classic, object): pass |
| |
| The MRO (method resolution order) for each base class is respected |
| according to its kind, but the MRO for the derived class is computed |
| using new-style MRO rules if any base class is a new-style class. |
| This needs to be documented. |
| |
| - The new builtin dictionary() constructor, and dictionary type, have |
| been renamed to dict. This reflects a decade of common usage. |
| |
| - dict() now accepts an iterable object producing 2-sequences. For |
| example, dict(d.items()) == d for any dictionary d. The argument, |
| and the elements of the argument, can be any iterable objects. |
| |
| - New-style classes can now have a __del__ method, which is called |
| when the instance is deleted (just like for classic classes). |
| |
| - Assignment to object.__dict__ is now possible, for objects that are |
| instances of new-style classes that have a __dict__ (unless the base |
| class forbids it). |
| |
| - Methods of built-in types now properly check for keyword arguments |
| (formerly these were silently ignored). The only built-in methods |
| that take keyword arguments are __call__, __init__ and __new__. |
| |
| - The socket function has been converted to a type; see below. |
| |
| Core and builtins |
| ----------------- |
| |
| - Assignment to __debug__ raises SyntaxError at compile-time. This |
| was promised when 2.1c1 was released as "What's New in Python 2.1c1" |
| (see below) says. |
| |
| - Clarified the error messages for unsupported operands to an operator |
| (like 1 + ''). |
| |
| Extension modules |
| ----------------- |
| |
| - mmap has a new keyword argument, "access", allowing a uniform way for |
| both Windows and Unix users to create read-only, write-through and |
| copy-on-write memory mappings. This was previously possible only on |
| Unix. A new keyword argument was required to support this in a |
| uniform way because the mmap() signatures had diverged across |
| platforms. Thanks to Jay T Miller for repairing this! |
| |
| - By default, the gc.garbage list now contains only those instances in |
| unreachable cycles that have __del__ methods; in 2.1 it contained all |
| instances in unreachable cycles. "Instances" here has been generalized |
| to include instances of both new-style and old-style classes. |
| |
| - The socket module defines a new method for socket objects, |
| sendall(). This is like send() but may make multiple calls to |
| send() until all data has been sent. Also, the socket function has |
| been converted to a subclassable type, like list and tuple (etc.) |
| before it; socket and SocketType are now the same thing. |
| |
| - Various bugfixes to the curses module. There is now a test suite |
| for the curses module (you have to run it manually). |
| |
| - binascii.b2a_base64 no longer places an arbitrary restriction of 57 |
| bytes on its input. |
| |
| Library |
| ------- |
| |
| - tkFileDialog exposes a Directory class and askdirectory |
| convenience function. |
| |
| - Symbolic group names in regular expressions must be unique. For |
| example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a |
| single name can't mean both "group 1" and "group 2" simultaneously. |
| Python 2.2 detects this error at regexp compilation time; |
| previously, the error went undetected, and results were |
| unpredictable. Also in sre, the pattern.split(), pattern.sub(), and |
| pattern.subn() methods have been rewritten in C. Also, an |
| experimental function/method finditer() has been added, which works |
| like findall() but returns an iterator. |
| |
| - Tix exposes more commands through the classes DirSelectBox, |
| DirSelectDialog, ListNoteBook, Meter, CheckList, and the |
| methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog, |
| tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions. |
| |
| - Traceback objects are now scanned by cyclic garbage collection, so |
| cycles created by casual use of sys.exc_info() no longer cause |
| permanent memory leaks (provided garbage collection is enabled). |
| |
| - os.extsep -- a new variable needed by the RISCOS support. It is the |
| separator used by extensions, and is '.' on all platforms except |
| RISCOS, where it is '/'. There is no need to use this variable |
| unless you have a masochistic desire to port your code to RISCOS. |
| |
| - mimetypes.py has optional support for non-standard, but commonly |
| found types. guess_type() and guess_extension() now accept an |
| optional 'strict' flag, defaulting to true, which controls whether |
| recognize non-standard types or not. A few non-standard types we |
| know about have been added. Also, when run as a script, there are |
| new -l and -e options. |
| |
| - statcache is now deprecated. |
| |
| - email.Utils.formatdate() now produces the preferred RFC 2822 style |
| dates with numeric timezones (it used to produce obsolete dates |
| hard coded to "GMT" timezone). An optional 'localtime' flag is |
| added to produce dates in the local timezone, with daylight savings |
| time properly taken into account. |
| |
| - In pickle and cPickle, instead of masking errors in load() by |
| transforming them into SystemError, we let the original exception |
| propagate out. Also, implement support for __safe_for_unpickling__ |
| in pickle, as it already was supported in cPickle. |
| |
| Tools/Demos |
| ----------- |
| |
| Build |
| ----- |
| |
| - The dbm module is built using libdb1 if available. The bsddb module |
| is built with libdb3 if available. |
| |
| - Misc/Makefile.pre.in has been removed by BDFL pronouncement. |
| |
| C API |
| ----- |
| |
| - New function PySequence_Fast_GET_SIZE() returns the size of a non- |
| NULL result from PySequence_Fast(), more quickly than calling |
| PySequence_Size(). |
| |
| - New argument unpacking function PyArg_UnpackTuple() added. |
| |
| - New functions PyObject_CallFunctionObjArgs() and |
| PyObject_CallMethodObjArgs() have been added to make it more |
| convenient and efficient to call functions and methods from C. |
| |
| - PyArg_ParseTupleAndKeywords() no longer masks errors, so it's |
| possible that this will propagate errors it didn't before. |
| |
| - New function PyObject_CheckReadBuffer(), which returns true if its |
| argument supports the single-segment readable buffer interface. |
| |
| New platforms |
| ------------- |
| |
| - We've finally confirmed that this release builds on HP-UX 11.00, |
| *with* threads, and passes the test suite. |
| |
| - Thanks to a series of patches from Michael Muller, Python may build |
| again under OS/2 Visual Age C++. |
| |
| - Updated RISCOS port by Dietmar Schwertberger. |
| |
| Tests |
| ----- |
| |
| - Added a test script for the curses module. It isn't run automatically; |
| regrtest.py must be run with '-u curses' to enable it. |
| |
| Windows |
| ------- |
| |
| Mac |
| ---- |
| |
| - PythonScript has been moved to unsupported and is slated to be |
| removed completely in the next release. |
| |
| - It should now be possible to build applets that work on both OS9 and |
| OSX. |
| |
| - The core is now linked with CoreServices not Carbon; as a side |
| result, default 8bit encoding on OSX is now ASCII. |
| |
| - Python should now build on OSX 10.1.1 |
| |
| |
| What's New in Python 2.2b1? |
| =========================== |
| |
| *Release date: 19-Oct-2001* |
| |
| Type/class unification and new-style classes |
| -------------------------------------------- |
| |
| - New-style classes are now always dynamic (except for built-in and |
| extension types). There is no longer a performance penalty, and I |
| no longer see another reason to keep this baggage around. One relic |
| remains: the __dict__ of a new-style class is a read-only proxy; you |
| must set the class's attribute to modify it. As a consequence, the |
| __defined__ attribute of new-style types no longer exists, for lack |
| of need: there is once again only one __dict__ (although in the |
| future a __cache__ may be resurrected with a similar function, if I |
| can prove that it actually speeds things up). |
| |
| - C.__doc__ now works as expected for new-style classes (in 2.2a4 it |
| always returned None, even when there was a class docstring). |
| |
| - doctest now finds and runs docstrings attached to new-style classes, |
| class methods, static methods, and properties. |
| |
| Core and builtins |
| ----------------- |
| |
| - A very subtle syntactical pitfall in list comprehensions was fixed. |
| For example: [a+b for a in 'abc', for b in 'def']. The comma in |
| this example is a mistake. Previously, this would silently let 'a' |
| iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce', |
| 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be', |
| 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error. |
| Note that [a for a in <singleton>] is a convoluted way to say |
| [<singleton>] anyway, so it's not like any expressiveness is lost. |
| |
| - getattr(obj, name, default) now only catches AttributeError, as |
| documented, rather than returning the default value for all |
| exceptions (which could mask bugs in a __getattr__ hook, for |
| example). |
| |
| - Weak reference objects are now part of the core and offer a C API. |
| A bug which could allow a core dump when binary operations involved |
| proxy reference has been fixed. weakref.ReferenceError is now a |
| built-in exception. |
| |
| - unicode(obj) now behaves more like str(obj), accepting arbitrary |
| objects, and calling a __unicode__ method if it exists. |
| unicode(obj, encoding) and unicode(obj, encoding, errors) still |
| require an 8-bit string or character buffer argument. |
| |
| - isinstance() now allows any object as the first argument and a |
| class, a type or something with a __bases__ tuple attribute for the |
| second argument. The second argument may also be a tuple of a |
| class, type, or something with __bases__, in which case isinstance() |
| will return true if the first argument is an instance of any of the |
| things contained in the second argument tuple. E.g. |
| |
| isinstance(x, (A, B)) |
| |
| returns true if x is an instance of A or B. |
| |
| Extension modules |
| ----------------- |
| |
| - thread.start_new_thread() now returns the thread ID (previously None). |
| |
| - binascii has now two quopri support functions, a2b_qp and b2a_qp. |
| |
| - readline now supports setting the startup_hook and the |
| pre_event_hook, and adds the add_history() function. |
| |
| - os and posix supports chroot(), setgroups() and unsetenv() where |
| available. The stat(), fstat(), statvfs() and fstatvfs() functions |
| now return "pseudo-sequences" -- the various fields can now be |
| accessed as attributes (e.g. os.stat("/").st_mtime) but for |
| backwards compatibility they also behave as a fixed-length sequence. |
| Some platform-specific fields (e.g. st_rdev) are only accessible as |
| attributes. |
| |
| - time: localtime(), gmtime() and strptime() now return a |
| pseudo-sequence similar to the os.stat() return value, with |
| attributes like tm_year etc. |
| |
| - Decompression objects in the zlib module now accept an optional |
| second parameter to decompress() that specifies the maximum amount |
| of memory to use for the uncompressed data. |
| |
| - optional SSL support in the socket module now exports OpenSSL |
| functions RAND_add(), RAND_egd(), and RAND_status(). These calls |
| are useful on platforms like Solaris where OpenSSL does not |
| automatically seed its PRNG. Also, the keyfile and certfile |
| arguments to socket.ssl() are now optional. |
| |
| - posixmodule (and by extension, the os module on POSIX platforms) now |
| exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW. |
| |
| Library |
| ------- |
| |
| - doctest now excludes functions and classes not defined by the module |
| being tested, thanks to Tim Hochberg. |
| |
| - HotShot, a new profiler implemented using a C-based callback, has |
| been added. This substantially reduces the overhead of profiling, |
| but it is still quite preliminary. Support modules and |
| documentation will be added in upcoming releases (before 2.2 final). |
| |
| - profile now produces correct output in situations where an exception |
| raised in Python is cleared by C code (e.g. hasattr()). This used |
| to cause wrong output, including spurious claims of recursive |
| functions and attribution of time spent to the wrong function. |
| |
| The code and documentation for the derived OldProfile and HotProfile |
| profiling classes was removed. The code hasn't worked for years (if |
| you tried to use them, they raised exceptions). OldProfile |
| intended to reproduce the behavior of the profiler Python used more |
| than 7 years ago, and isn't interesting anymore. HotProfile intended |
| to provide a faster profiler (but producing less information), and |
| that's a worthy goal we intend to meet via a different approach (but |
| without losing information). |
| |
| - Profile.calibrate() has a new implementation that should deliver |
| a much better system-specific calibration constant. The constant can |
| now be specified in an instance constructor, or as a Profile class or |
| instance variable, instead of by editing profile.py's source code. |
| Calibration must still be done manually (see the docs for the profile |
| module). |
| |
| Note that Profile.calibrate() must be overriden by subclasses. |
| Improving the accuracy required exploiting detailed knowledge of |
| profiler internals; the earlier method abstracted away the details |
| and measured a simplified model instead, but consequently computed |
| a constant too small by a factor of 2 on some modern machines. |
| |
| - quopri's encode and decode methods take an optional header parameter, |
| which indicates whether output is intended for the header 'Q' |
| encoding. |
| |
| - The SocketServer.ThreadingMixIn class now closes the request after |
| finish_request() returns. (Not when it errors out though.) |
| |
| - The nntplib module's NNTP.body() method has grown a 'file' argument |
| to allow saving the message body to a file. |
| |
| - The email package has added a class email.Parser.HeaderParser which |
| only parses headers and does not recurse into the message's body. |
| Also, the module/class MIMEAudio has been added for representing |
| audio data (contributed by Anthony Baxter). |
| |
| - ftplib should be able to handle files > 2GB. |
| |
| - ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO, |
| ON, and OFF. |
| |
| - xml.dom.minidom NodeList objects now support the length attribute |
| and item() method as required by the DOM specifications. |
| |
| Tools/Demos |
| ----------- |
| |
| - Demo/dns was removed. It no longer serves any purpose; a package |
| derived from it is now maintained by Anthony Baxter, see |
| http://PyDNS.SourceForge.net. |
| |
| - The freeze tool has been made more robust, and two new options have |
| been added: -X and -E. |
| |
| Build |
| ----- |
| |
| - configure will use CXX in LINKCC if CXX is used to build main() and |
| the system requires to link a C++ main using the C++ compiler. |
| |
| C API |
| ----- |
| |
| - The documentation for the tp_compare slot is updated to require that |
| the return value must be -1, 0, 1; an arbitrary number <0 or >0 is |
| not correct. This is not yet enforced but will be enforced in |
| Python 2.3; even later, we may use -2 to indicate errors and +2 for |
| "NotImplemented". Right now, -1 should be used for an error return. |
| |
| - PyLong_AsLongLong() now accepts int (as well as long) arguments. |
| Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well |
| as long) arguments. |
| |
| - PyThread_start_new_thread() now returns a long int giving the thread |
| ID, if one can be calculated; it returns -1 for error, 0 if no |
| thread ID is calculated (this is an incompatible change, but only |
| the thread module used this API). This code has only really been |
| tested on Linux and Windows; other platforms please beware (and |
| report any bugs or strange behavior). |
| |
| - PyUnicode_FromEncodedObject() no longer accepts Unicode objects as |
| input. |
| |
| New platforms |
| ------------- |
| |
| Tests |
| ----- |
| |
| Windows |
| ------- |
| |
| - Installer: If you install IDLE, and don't disable file-extension |
| registration, a new "Edit with IDLE" context (right-click) menu entry |
| is created for .py and .pyw files. |
| |
| - The signal module now supports SIGBREAK on Windows, thanks to Steven |
| Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK |
| action remains to call Win32 ExitProcess(). This can be changed via |
| signal.signal(). For example:: |
| |
| # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C |
| # (SIGINT) behavior. |
| import signal |
| signal.signal(signal.SIGBREAK, signal.default_int_handler) |
| |
| try: |
| while 1: |
| pass |
| except KeyboardInterrupt: |
| # We get here on Ctrl+C or Ctrl+Break now; if we had not changed |
| # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the |
| # program without the possibility for any Python-level cleanup). |
| print "Clean exit" |
| |
| |
| What's New in Python 2.2a4? |
| =========================== |
| |
| *Release date: 28-Sep-2001* |
| |
| Type/class unification and new-style classes |
| -------------------------------------------- |
| |
| - pydoc and inspect are now aware of new-style classes; |
| e.g. help(list) at the interactive prompt now shows proper |
| documentation for all operations on list objects. |
| |
| - Applications using Jim Fulton's ExtensionClass module can now safely |
| be used with Python 2.2. In particular, Zope 2.4.1 now works with |
| Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass |
| examples also work again. It is hoped that Gtk and Boost also work |
| with 2.2a4 and beyond. (If you can confirm this, please write |
| webmaster@python.org; if there are still problems, please open a bug |
| report on SourceForge.) |
| |
| - property() now takes 4 keyword arguments: fget, fset, fdel and doc. |
| These map to read-only attributes 'fget', 'fset', 'fdel', and '__doc__' |
| in the constructed property object. fget, fset and fdel weren't |
| discoverable from Python in 2.2a3. __doc__ is new, and allows to |
| associate a docstring with a property. |
| |
| - Comparison overloading is now more completely implemented. For |
| example, a str subclass instance can properly be compared to a str |
| instance, and it can properly overload comparison. Ditto for most |
| other built-in object types. |
| |
| - The repr() of new-style classes has changed; instead of <type |
| 'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>, |
| *except* for built-in types, which are still rendered as <type |
| 'Foo'> (to avoid upsetting existing code that might parse or |
| otherwise rely on repr() of certain type objects). |
| |
| - The repr() of new-style objects is now always <Foo object at XXX>; |
| previously, it was sometimes <Foo instance at XXX>. |
| |
| - For new-style classes, what was previously called __getattr__ is now |
| called __getattribute__. This method, if defined, is called for |
| *every* attribute access. A new __getattr__ hook more similar to the |
| one in classic classes is defined which is called only if regular |
| attribute access raises AttributeError; to catch *all* attribute |
| access, you can use __getattribute__ (for new-style classes). If |
| both are defined, __getattribute__ is called first, and if it raises |
| AttributeError, __getattr__ is called. |
| |
| - The __class__ attribute of new-style objects can be assigned to. |
| The new class must have the same C-level object layout as the old |
| class. |
| |
| - The builtin file type can be subclassed now. In the usual pattern, |
| "file" is the name of the builtin type, and file() is a new builtin |
| constructor, with the same signature as the builtin open() function. |
| file() is now the preferred way to open a file. |
| |
| - Previously, __new__ would only see sequential arguments passed to |
| the type in a constructor call; __init__ would see both sequential |
| and keyword arguments. This made no sense whatsoever any more, so |
| now both __new__ and __init__ see all arguments. |
| |
| - Previously, hash() applied to an instance of a subclass of str or |
| unicode always returned 0. This has been repaired. |
| |
| - Previously, an operation on an instance of a subclass of an |
| immutable type (int, long, float, complex, tuple, str, unicode), |
| where the subtype didn't override the operation (and so the |
| operation was handled by the builtin type), could return that |
| instance instead a value of the base type. For example, if s was of |
| a str subclass type, s[:] returned s as-is. Now it returns a str |
| with the same value as s. |
| |
| - Provisional support for pickling new-style objects has been added. |
| |
| Core |
| ---- |
| |
| - file.writelines() now accepts any iterable object producing strings. |
| |
| - PyUnicode_FromEncodedObject() now works very much like |
| PyObject_Str(obj) in that it tries to use __str__/tp_str |
| on the object if the object is not a string or buffer. This |
| makes unicode() behave like str() when applied to non-string/buffer |
| objects. |
| |
| - PyFile_WriteObject now passes Unicode objects to the file's write |
| method. As a result, all file-like objects which may be the target |
| of a print statement must support Unicode objects, i.e. they must |
| at least convert them into ASCII strings. |
| |
| - Thread scheduling on Solaris should be improved; it is no longer |
| necessary to insert a small sleep at the start of a thread in order |
| to let other runnable threads be scheduled. |
| |
| Library |
| ------- |
| |
| - StringIO.StringIO instances and cStringIO.StringIO instances support |
| read character buffer compatible objects for their .write() methods. |
| These objects are converted to strings and then handled as such |
| by the instances. |
| |
| - The "email" package has been added. This is basically a port of the |
| mimelib package <http://sf.net/projects/mimelib> with API changes |
| and some implementations updated to use iterators and generators. |
| |
| - difflib.ndiff() and difflib.Differ.compare() are generators now. This |
| restores the ability of Tools/scripts/ndiff.py to start producing output |
| before the entire comparison is complete. |
| |
| - StringIO.StringIO instances and cStringIO.StringIO instances support |
| iteration just like file objects (i.e. their .readline() method is |
| called for each iteration until it returns an empty string). |
| |
| - The codecs module has grown four new helper APIs to access |
| builtin codecs: getencoder(), getdecoder(), getreader(), |
| getwriter(). |
| |
| - SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer) |
| simplifies writing XML RPC servers. |
| |
| - os.path.realpath(): a new function that returns the absolute pathname |
| after interpretation of symbolic links. On non-Unix systems, this |
| is an alias for os.path.abspath(). |
| |
| - operator.indexOf() (PySequence_Index() in the C API) now works with any |
| iterable object. |
| |
| - smtplib now supports various authentication and security features of |
| the SMTP protocol through the new login() and starttls() methods. |
| |
| - hmac: a new module implementing keyed hashing for message |
| authentication. |
| |
| - mimetypes now recognizes more extensions and file types. At the |
| same time, some mappings not sanctioned by IANA were removed. |
| |
| - The "compiler" package has been brought up to date to the state of |
| Python 2.2 bytecode generation. It has also been promoted from a |
| Tool to a standard library package. (Tools/compiler still exists as |
| a sample driver.) |
| |
| Tools |
| ----- |
| |
| Build |
| ----- |
| |
| - Large file support (LFS) is now automatic when the platform supports |
| it; no more manual configuration tweaks are needed. On Linux, at |
| least, it's possible to have a system whose C library supports large |
| files but whose kernel doesn't; in this case, large file support is |
| still enabled but doesn't do you any good unless you upgrade your |
| kernel or share your Python executable with another system whose |
| kernel has large file support. |
| |
| - The configure script now supplies plausible defaults in a |
| cross-compilation environment. This doesn't mean that the supplied |
| values are always correct, or that cross-compilation now works |
| flawlessly -- but it's a first step (and it shuts up most of |
| autoconf's warnings about AC_TRY_RUN). |
| |
| - The Unix build is now a bit less chatty, courtesy of the parser |
| generator. The build is completely silent (except for errors) when |
| using "make -s", thanks to a -q option to setup.py. |
| |
| C API |
| ----- |
| |
| - The "structmember" API now supports some new flag bits to deny read |
| and/or write access to attributes in restricted execution mode. |
| |
| New platforms |
| ------------- |
| |
| - Compaq's iPAQ handheld, running the "familiar" Linux distribution |
| (http://familiar.handhelds.org). |
| |
| Tests |
| ----- |
| |
| - The "classic" standard tests, which work by comparing stdout to |
| an expected-output file under Lib/test/output/, no longer stop at |
| the first mismatch. Instead the test is run to completion, and a |
| variant of ndiff-style comparison is used to report all differences. |
| This is much easier to understand than the previous style of reporting. |
| |
| - The unittest-based standard tests now use regrtest's test_main() |
| convention, instead of running as a side-effect of merely being |
| imported. This allows these tests to be run in more natural and |
| flexible ways as unittests, outside the regrtest framework. |
| |
| - regrtest.py is much better integrated with unittest and doctest now, |
| especially in regard to reporting errors. |
| |
| Windows |
| ------- |
| |
| - Large file support now also works for files > 4GB, on filesystems |
| that support it (NTFS under Windows 2000). See "What's New in |
| Python 2.2a3" for more detail. |
| |
| |
| What's New in Python 2.2a3? |
| =========================== |
| |
| *Release Date: 07-Sep-2001* |
| |
| Core |
| ---- |
| |
| - Conversion of long to float now raises OverflowError if the long is too |
| big to represent as a C double. |
| |
| - The 3-argument builtin pow() no longer allows a third non-None argument |
| if either of the first two arguments is a float, or if both are of |
| integer types and the second argument is negative (in which latter case |
| the arguments are converted to float, so this is really the same |
| restriction). |
| |
| - The builtin dir() now returns more information, and sometimes much |
| more, generally naming all attributes of an object, and all attributes |
| reachable from the object via its class, and from its class's base |
| classes, and so on from them too. Example: in 2.2a2, dir([]) returned |
| an empty list. In 2.2a3, |
| |
| >>> dir([]) |
| ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__', |
| '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__', |
| '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__', |
| '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__', |
| '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__', |
| 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove', |
| 'reverse', 'sort'] |
| |
| dir(module) continues to return only the module's attributes, though. |
| |
| - Overflowing operations on plain ints now return a long int rather |
| than raising OverflowError. This is a partial implementation of PEP |
| 237. You can use -Wdefault::OverflowWarning to enable a warning for |
| this situation, and -Werror::OverflowWarning to revert to the old |
| OverflowError exception. |
| |
| - A new command line option, -Q<arg>, is added to control run-time |
| warnings for the use of classic division. (See PEP 238.) Possible |
| values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is |
| -Qold, meaning the / operator has its classic meaning and no |
| warnings are issued. Using -Qwarn issues a run-time warning about |
| all uses of classic division for int and long arguments; -Qwarnall |
| also warns about classic division for float and complex arguments |
| (for use with fixdiv.py). |
| [Note: the remainder of this item (preserved below) became |
| obsolete in 2.2c1 -- -Qnew has global effect in 2.2] :: |
| |
| Using -Qnew is questionable; it turns on new division by default, but |
| only in the __main__ module. You can usefully combine -Qwarn or |
| -Qwarnall and -Qnew: this gives the __main__ module new division, and |
| warns about classic division everywhere else. |
| |
| - Many built-in types can now be subclassed. This applies to int, |
| long, float, str, unicode, and tuple. (The types complex, list and |
| dictionary can also be subclassed; this was introduced earlier.) |
| Note that restrictions apply when subclassing immutable built-in |
| types: you can only affect the value of the instance by overloading |
| __new__. You can add mutable attributes, and the subclass instances |
| will have a __dict__ attribute, but you cannot change the "value" |
| (as implemented by the base class) of an immutable subclass instance |
| once it is created. |
| |
| - The dictionary constructor now takes an optional argument, a |
| mapping-like object, and initializes the dictionary from its |
| (key, value) pairs. |
| |
| - A new built-in type, super, has been added. This facilitates making |
| "cooperative super calls" in a multiple inheritance setting. For an |
| explanation, see http://www.python.org/2.2/descrintro.html#cooperation |
| |
| - A new built-in type, property, has been added. This enables the |
| creation of "properties". These are attributes implemented by |
| getter and setter functions (or only one of these for read-only or |
| write-only attributes), without the need to override __getattr__. |
| See http://www.python.org/2.2/descrintro.html#property |
| |
| - The syntax of floating-point and imaginary literals has been |
| liberalized, to allow leading zeroes. Examples of literals now |
| legal that were SyntaxErrors before: |
| |
| 00.0 0e3 0100j 07.5 00000000000000000008. |
| |
| - An old tokenizer bug allowed floating point literals with an incomplete |
| exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError. |
| |
| Library |
| ------- |
| |
| - telnetlib includes symbolic names for the options, and support for |
| setting an option negotiation callback. It also supports processing |
| of suboptions. |
| |
| - The new C standard no longer requires that math libraries set errno to |
| ERANGE on overflow. For platform libraries that exploit this new |
| freedom, Python's overflow-checking was wholly broken. A new overflow- |
| checking scheme attempts to repair that, but may not be reliable on all |
| platforms (C doesn't seem to provide anything both useful and portable |
| in this area anymore). |
| |
| - Asynchronous timeout actions are available through the new class |
| threading.Timer. |
| |
| - math.log and math.log10 now return sensible results for even huge |
| long arguments. For example, math.log10(10 ** 10000) ~= 10000.0. |
| |
| - A new function, imp.lock_held(), returns 1 when the import lock is |
| currently held. See the docs for the imp module. |
| |
| - pickle, cPickle and marshal on 32-bit platforms can now correctly read |
| dumps containing ints written on platforms where Python ints are 8 bytes. |
| When read on a box where Python ints are 4 bytes, such values are |
| converted to Python longs. |
| |
| - In restricted execution mode (using the rexec module), unmarshalling |
| code objects is no longer allowed. This plugs a security hole. |
| |
| - unittest.TestResult instances no longer store references to tracebacks |
| generated by test failures. This prevents unexpected dangling references |
| to objects that should be garbage collected between tests. |
| |
| Tools |
| ----- |
| |
| - Tools/scripts/fixdiv.py has been added which can be used to fix |
| division operators as per PEP 238. |
| |
| Build |
| ----- |
| |
| - If you are an adventurous person using Mac OS X you may want to look at |
| Mac/OSX. There is a Makefile there that will build Python as a real Mac |
| application, which can be used for experimenting with Carbon or Cocoa. |
| Discussion of this on pythonmac-sig, please. |
| |
| C API |
| ----- |
| |
| - New function PyObject_Dir(obj), like Python __builtin__.dir(obj). |
| |
| - Note that PyLong_AsDouble can fail! This has always been true, but no |
| callers checked for it. It's more likely to fail now, because overflow |
| errors are properly detected now. The proper way to check:: |
| |
| double x = PyLong_AsDouble(some_long_object); |
| if (x == -1.0 && PyErr_Occurred()) { |
| /* The conversion failed. */ |
| } |
| |
| - The GC API has been changed. Extensions that use the old API will still |
| compile but will not participate in GC. To upgrade an extension |
| module: |
| |
| - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC |
| |
| - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and |
| PyObject_GC_Del to deallocate them |
| |
| - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini |
| to PyObject_GC_UnTrack |
| |
| - remove PyGC_HEAD_SIZE from object size calculations |
| |
| - remove calls to PyObject_AS_GC and PyObject_FROM_GC |
| |
| - Two new functions: PyString_FromFormat() and PyString_FromFormatV(). |
| These can be used safely to construct string objects from a |
| sprintf-style format string (similar to the format string supported |
| by PyErr_Format()). |
| |
| New platforms |
| ------------- |
| |
| - Stephen Hansen contributed patches sufficient to get a clean compile |
| under Borland C (Windows), but he reports problems running it and ran |
| out of time to complete the port. Volunteers? Expect a MemoryError |
| when importing the types module; this is probably shallow, and |
| causing later failures too. |
| |
| Tests |
| ----- |
| |
| Windows |
| ------- |
| |
| - Large file support is now enabled on Win32 platforms as well as on |
| Win64. This means that, for example, you can use f.tell() and f.seek() |
| to manipulate files larger than 2 gigabytes (provided you have enough |
| disk space, and are using a Windows filesystem that supports large |
| partitions). Windows filesystem limits: FAT has a 2GB (gigabyte) |
| filesize limit, and large file support makes no difference there. |
| FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now. |
| NTFS has no practical limit on file size, and files of any size can be |
| used from Python now. |
| |
| - The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC |
| points to command.com (patch from Brian Quinlan). |
| |
| |
| What's New in Python 2.2a2? |
| =========================== |
| |
| *Release Date: 22-Aug-2001* |
| |
| Build |
| ----- |
| |
| - Tim Peters developed a brand new Windows installer using Wise 8.1, |
| generously donated to us by Wise Solutions. |
| |
| - configure supports a new option --enable-unicode, with the values |
| ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode |
| type and supporting code is completely removed from the interpreter. |
| |
| - A new configure option --enable-framework builds a Mac OS X framework, |
| which "make frameworkinstall" will install. This provides a starting |
| point for more mac-like functionality, join pythonmac-sig@python.org |
| if you are interested in helping. |
| |
| - The NeXT platform is no longer supported. |
| |
| - The 'new' module is now statically linked. |
| |
| Tools |
| ----- |
| |
| - The new Tools/scripts/cleanfuture.py can be used to automatically |
| edit out obsolete future statements from Python source code. See |
| the module docstring for details. |
| |
| Tests |
| ----- |
| |
| - regrtest.py now knows which tests are expected to be skipped on some |
| platforms, allowing to give clearer test result output. regrtest |
| also has optional --use/-u switch to run normally disabled tests |
| which require network access or consume significant disk resources. |
| |
| - Several new tests in the standard test suite, with special thanks to |
| Nick Mathewson. |
| |
| Core |
| ---- |
| |
| - The floor division operator // has been added as outlined in PEP |
| 238. The / operator still provides classic division (and will until |
| Python 3.0) unless "from __future__ import division" is included, in |
| which case the / operator will provide true division. The operator |
| module provides truediv() and floordiv() functions. Augmented |
| assignment variants are included, as are the equivalent overloadable |
| methods and C API methods. See the PEP for a full discussion: |
| <http://python.sf.net/peps/pep-0238.html> |
| |
| - Future statements are now effective in simulated interactive shells |
| (like IDLE). This should "just work" by magic, but read Michael |
| Hudson's "Future statements in simulated shells" PEP 264 for full |
| details: <http://python.sf.net/peps/pep-0264.html>. |
| |
| - The type/class unification (PEP 252-253) was integrated into the |
| trunk and is not so tentative any more (the exact specification of |
| some features is still tentative). A lot of work has done on fixing |
| bugs and adding robustness and features (performance still has to |
| come a long way). |
| |
| - Warnings about a mismatch in the Python API during extension import |
| now use the Python warning framework (which makes it possible to |
| write filters for these warnings). |
| |
| - A function's __dict__ (aka func_dict) will now always be a |
| dictionary. It used to be possible to delete it or set it to None, |
| but now both actions raise TypeErrors. It is still legal to set it |
| to a dictionary object. Getting func.__dict__ before any attributes |
| have been assigned now returns an empty dictionary instead of None. |
| |
| - A new command line option, -E, was added which disables the use of |
| all environment variables, or at least those that are specifically |
| significant to Python. Usually those have a name starting with |
| "PYTHON". This was used to fix a problem where the tests fail if |
| the user happens to have PYTHONHOME or PYTHONPATH pointing to an |
| older distribution. |
| |
| Library |
| ------- |
| |
| - New class Differ and new functions ndiff() and restore() in difflib.py. |
| These package the algorithms used by the popular Tools/scripts/ndiff.py, |
| for programmatic reuse. |
| |
| - New function xml.sax.saxutils.quoteattr(): Quote an XML attribute |
| value using the minimal quoting required for the value; more |
| reliable than using xml.sax.saxutils.escape() for attribute values. |
| |
| - Readline completion support for cmd.Cmd was added. |
| |
| - Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings. |
| |
| - Added function threading.BoundedSemaphore() |
| |
| - Added Ka-Ping Yee's cgitb.py module. |
| |
| - The 'new' module now exposes the CO_xxx flags. |
| |
| - The gc module offers the get_referents function. |
| |
| New platforms |
| ------------- |
| |
| C API |
| ----- |
| |
| - Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added |
| which provide a cross-platform implementations for the |
| relatively new snprintf()/vsnprintf() C lib APIs. In contrast to |
| the standard sprintf() and vsprintf() C lib APIs, these versions |
| apply bounds checking on the used buffer which enhances protection |
| against buffer overruns. |
| |
| - Unicode APIs now use name mangling to assure that mixing interpreters |
| and extensions using different Unicode widths is rendered next to |
| impossible. Trying to import an incompatible Unicode-aware extension |
| will result in an ImportError. Unicode extensions writers must make |
| sure to check the Unicode width compatibility in their extensions by |
| using at least one of the mangled Unicode APIs in the extension. |
| |
| - Two new flags METH_NOARGS and METH_O are available in method definition |
| tables to simplify implementation of methods with no arguments and a |
| single untyped argument. Calling such methods is more efficient than |
| calling corresponding METH_VARARGS methods. METH_OLDARGS is now |
| deprecated. |
| |
| Windows |
| ------- |
| |
| - "import module" now compiles module.pyw if it exists and nothing else |
| relevant is found. |
| |
| |
| What's New in Python 2.2a1? |
| =========================== |
| |
| *Release date: 18-Jul-2001* |
| |
| Core |
| ---- |
| |
| - TENTATIVELY, a large amount of code implementing much of what's |
| described in PEP 252 (Making Types Look More Like Classes) and PEP |
| 253 (Subtyping Built-in Types) was added. This will be released |
| with Python 2.2a1. Documentation will be provided separately |
| through http://www.python.org/2.2/. The purpose of releasing this |
| with Python 2.2a1 is to test backwards compatibility. It is |
| possible, though not likely, that a decision is made not to release |
| this code as part of 2.2 final, if any serious backwards |
| incompatibilities are found during alpha testing that cannot be |
| repaired. |
| |
| - Generators were added; this is a new way to create an iterator (see |
| below) using what looks like a simple function containing one or |
| more 'yield' statements. See PEP 255. Since this adds a new |
| keyword to the language, this feature must be enabled by including a |
| future statement: "from __future__ import generators" (see PEP 236). |
| Generators will become a standard feature in a future release |
| (probably 2.3). Without this future statement, 'yield' remains an |
| ordinary identifier, but a warning is issued each time it is used. |
| (These warnings currently don't conform to the warnings framework of |
| PEP 230; we intend to fix this in 2.2a2.) |
| |
| - The UTF-16 codec was modified to be more RFC compliant. It will now |
| only remove BOM characters at the start of the string and then |
| only if running in native mode (UTF-16-LE and -BE won't remove a |
| leading BMO character). |
| |
| - Strings now have a new method .decode() to complement the already |
| existing .encode() method. These two methods provide direct access |
| to the corresponding decoders and encoders of the registered codecs. |
| |
| To enhance the usability of the .encode() method, the special |
| casing of Unicode object return values was dropped (Unicode objects |
| were auto-magically converted to string using the default encoding). |
| |
| Both methods will now return whatever the codec in charge of the |
| requested encoding returns as object, e.g. Unicode codecs will |
| return Unicode objects when decoding is requested ("äöü".decode("latin-1") |
| will return u"äöü"). This enables codec writer to create codecs |
| for various simple to use conversions. |
| |
| New codecs were added to demonstrate these new features (the .encode() |
| and .decode() columns indicate the type of the returned objects): |
| |
| +---------+-----------+-----------+-----------------------------+ |
| |Name | .encode() | .decode() | Description | |
| +=========+===========+===========+=============================+ |
| |uu | string | string | UU codec (e.g. for email) | |
| +---------+-----------+-----------+-----------------------------+ |
| |base64 | string | string | base64 codec | |
| +---------+-----------+-----------+-----------------------------+ |
| |quopri | string | string | quoted-printable codec | |
| +---------+-----------+-----------+-----------------------------+ |
| |zlib | string | string | zlib compression | |
| +---------+-----------+-----------+-----------------------------+ |
| |hex | string | string | 2-byte hex codec | |
| +---------+-----------+-----------+-----------------------------+ |
| |rot-13 | string | Unicode | ROT-13 Unicode charmap codec| |
| +---------+-----------+-----------+-----------------------------+ |
| |
| - Some operating systems now support the concept of a default Unicode |
| encoding for file system operations. Notably, Windows supports 'mbcs' |
| as the default. The Macintosh will also adopt this concept in the medium |
| term, although the default encoding for that platform will be other than |
| 'mbcs'. |
| |
| On operating system that support non-ASCII filenames, it is common for |
| functions that return filenames (such as os.listdir()) to return Python |
| string objects pre-encoded using the default file system encoding for |
| the platform. As this encoding is likely to be different from Python's |
| default encoding, converting this name to a Unicode object before passing |
| it back to the Operating System would result in a Unicode error, as Python |
| would attempt to use its default encoding (generally ASCII) rather than |
| the default encoding for the file system. |
| |
| In general, this change simply removes surprises when working with |
| Unicode and the file system, making these operations work as you expect, |
| increasing the transparency of Unicode objects in this context. |
| See [????] for more details, including examples. |
| |
| - Float (and complex) literals in source code were evaluated to full |
| precision only when running from a .py file; the same code loaded from a |
| .pyc (or .pyo) file could suffer numeric differences starting at about the |
| 12th significant decimal digit. For example, on a machine with IEEE-754 |
| floating arithmetic, |
| |
| x = 9007199254740992.0 |
| print long(x) |
| |
| printed 9007199254740992 if run directly from .py, but 9007199254740000 |
| if from a compiled (.pyc or .pyo) file. This was due to marshal using |
| str(float) instead of repr(float) when building code objects. marshal |
| now uses repr(float) instead, which should reproduce floats to full |
| machine precision (assuming the platform C float<->string I/O conversion |
| functions are of good quality). |
| |
| This may cause floating-point results to change in some cases, and |
| usually for the better, but may also cause numerically unstable |
| algorithms to break. |
| |
| - The implementation of dicts suffers fewer collisions, which has speed |
| benefits. However, the order in which dict entries appear in dict.keys(), |
| dict.values() and dict.items() may differ from previous releases for a |
| given dict. Nothing is defined about this order, so no program should |
| rely on it. Nevertheless, it's easy to write test cases that rely on the |
| order by accident, typically because of printing the str() or repr() of a |
| dict to an "expected results" file. See Lib/test/test_support.py's new |
| sortdict(dict) function for a simple way to display a dict in sorted |
| order. |
| |
| - Many other small changes to dicts were made, resulting in faster |
| operation along the most common code paths. |
| |
| - Dictionary objects now support the "in" operator: "x in dict" means |
| the same as dict.has_key(x). |
| |
| - The update() method of dictionaries now accepts generic mapping |
| objects. Specifically the argument object must support the .keys() |
| and __getitem__() methods. This allows you to say, for example, |
| {}.update(UserDict()) |
| |
| - Iterators were added; this is a generalized way of providing values |
| to a for loop. See PEP 234. There's a new built-in function iter() |
| to return an iterator. There's a new protocol to get the next value |
| from an iterator using the next() method (in Python) or the |
| tp_iternext slot (in C). There's a new protocol to get iterators |
| using the __iter__() method (in Python) or the tp_iter slot (in C). |
| Iterating (i.e. a for loop) over a dictionary generates its keys. |
| Iterating over a file generates its lines. |
| |
| - The following functions were generalized to work nicely with iterator |
| arguments:: |
| |
| map(), filter(), reduce(), zip() |
| list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API) |
| max(), min() |
| join() method of strings |
| extend() method of lists |
| 'x in y' and 'x not in y' (PySequence_Contains() in C API) |
| operator.countOf() (PySequence_Count() in C API) |
| right-hand side of assignment statements with multiple targets, such as :: |
| x, y, z = some_iterable_object_returning_exactly_3_values |
| |
| - Accessing module attributes is significantly faster (for example, |
| random.random or os.path or yourPythonModule.yourAttribute). |
| |
| - Comparing dictionary objects via == and != is faster, and now works even |
| if the keys and values don't support comparisons other than ==. |
| |
| - Comparing dictionaries in ways other than == and != is slower: there were |
| insecurities in the dict comparison implementation that could cause Python |
| to crash if the element comparison routines for the dict keys and/or |
| values mutated the dicts. Making the code bulletproof slowed it down. |
| |
| - Collisions in dicts are resolved via a new approach, which can help |
| dramatically in bad cases. For example, looking up every key in a dict |
| d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x |
| faster now. Thanks to Christian Tismer for pointing out the cause and |
| the nature of an effective cure (last December! better late than never). |
| |
| - repr() is much faster for large containers (dict, list, tuple). |
| |
| |
| Library |
| ------- |
| |
| - The constants ascii_letters, ascii_lowercase. and ascii_uppercase |
| were added to the string module. These a locale-independent |
| constants, unlike letters, lowercase, and uppercase. These are now |
| use in appropriate locations in the standard library. |
| |
| - The flags used in dlopen calls can now be configured using |
| sys.setdlopenflags and queried using sys.getdlopenflags. |
| |
| - Fredrik Lundh's xmlrpclib is now a standard library module. This |
| provides full client-side XML-RPC support. In addition, |
| Demo/xmlrpc/ contains two server frameworks (one SocketServer-based, |
| one asyncore-based). Thanks to Eric Raymond for the documentation. |
| |
| - The xrange() object is simplified: it no longer supports slicing, |
| repetition, comparisons, efficient 'in' checking, the tolist() |
| method, or the start, stop and step attributes. See PEP 260. |
| |
| - A new function fnmatch.filter to filter lists of file names was added. |
| |
| - calendar.py uses month and day names based on the current locale. |
| |
| - strop is now *really* obsolete (this was announced before with 1.6), |
| and issues DeprecationWarning when used (except for the four items |
| that are still imported into string.py). |
| |
| - Cookie.py now sorts key+value pairs by key in output strings. |
| |
| - pprint.isrecursive(object) didn't correctly identify recursive objects. |
| Now it does. |
| |
| - pprint functions now much faster for large containers (tuple, list, dict). |
| |
| - New 'q' and 'Q' format codes in the struct module, corresponding to C |
| types "long long" and "unsigned long long" (on Windows, __int64). In |
| native mode, these can be used only when the platform C compiler supports |
| these types (when HAVE_LONG_LONG is #define'd by the Python config |
| process), and then they inherit the sizes and alignments of the C types. |
| In standard mode, 'q' and 'Q' are supported on all platforms, and are |
| 8-byte integral types. |
| |
| - The site module installs a new built-in function 'help' that invokes |
| pydoc.help. It must be invoked as 'help()'; when invoked as 'help', |
| it displays a message reminding the user to use 'help()' or |
| 'help(object)'. |
| |
| Tests |
| ----- |
| |
| - New test_mutants.py runs dict comparisons where the key and value |
| comparison operators mutate the dicts randomly during comparison. This |
| rapidly causes Python to crash under earlier releases (not for the faint |
| of heart: it can also cause Win9x to freeze or reboot!). |
| |
| - New test_pprint.py verifies that pprint.isrecursive() and |
| pprint.isreadable() return sensible results. Also verifies that simple |
| cases produce correct output. |
| |
| C API |
| ----- |
| |
| - Removed the unused last_is_sticky argument from the internal |
| _PyTuple_Resize(). If this affects you, you were cheating. |
| |
| ---- |
| |
| **(For information about older versions, consult the HISTORY file.)** |