cpython/Misc/NEWS

New since 1.5a2
---------------

The following items are only relevant if you previously used Python
1.5a2:

- The strftime test should now succeed on Windows and Mac platforms,
too.  It still fails on some Linux platforms; I believe that this is a
problem in the C library on those platforms.



What's new in this release?
---------------------------

I haven't kept track closely, so here are just a few highlights.  For
the final release, I will go through all my RCS logs and distill a
complete list.  Note that the biggest unfinished project is
documentation.

XXX To be expanded:

- Tools/webchecker

- Lee Busby's SIGFPE mods and modules fpectl, fpetest

- formatter.*Writer.flush

- dis.{cmp_op, hascompare}

- ftplib: FTP.ntransfercmd, Netrc, parse150

- httplib.HTTP_VERSIONS_ACCEPTED

- new module keyword

- imghdr recognizes bmp, png

- mhlib, parsesequence improved

- mimify base64 support

- new.function revived

- popen2.popen3 added

- new module pprint

- cgi.FieldStorage: __len__ added

New exceptions:
	FloatingPointError
Deleted exception:
	ConflictError

>    audioop.ratecv

>     posix.O_APPEND
>     posix.O_CREAT
>     posix.O_DSYNC
>     posix.O_EXCL
>     posix.O_NDELAY
>     posix.O_NOCTTY
>     posix.O_NONBLOCK
>     posix.O_RDONLY
>     posix.O_RDWR
>     posix.O_RSYNC
>     posix.O_SYNC
>     posix.O_TRUNC
>     posix.O_WRONLY
	posix.O_TEXT
	posix.O_BINARY
(also in os, of course)

>     regex.get_syntax

>     socket.getprotobyname

>     strop.replace
Also string.replace

- Jack's buffer interface!
	- supported by regex module!

- improved dir() semantics

- posix.error, nt.error renamed to os.error

- rfc822 getdate_tz and parsedate_tz

- shelve.*.sync

- shutil improved interface

- socket.getprotobynameo

- _xdrmodule is gone (in favor of structmodule)

- xdrlib.Unpacker.get_buffer

- much improved structmodule

- Tkinter upgraded (as always)

- new al module for SGI

- file object readinto methods

- tktrace???

Obsolete: cgensupport.[ch] are now in Modules and only linked with glmodule.c.

- much faster file.read() and readlines() on windows

======================================================================

- PyObject_Compare() can now raise an exception.  Check with
PyErr_Occurred().  The comparison function in an object type may also
raise an exception.

- The slice interface uses an upper bound of INT_MAX when no explicit
upper bound is given (e.x. for a[1:]).  It used to ask the object for
its length and do the calculations.

- I've completed the Grand Renaming, with the help of Roger Masse and
Barry Warsaw.  Many other unrelated code reorganizations have also
been carried out.

- As far as I can tell, neither gcc -Wall nor the Microsoft compiler
emits a single warning any more when compiling Python.

- It's much faster (almost twice for pystone.py -- see Tools/scripts.)

- Unless I hear a lot of protest, private variables with leading
double underscore are now a permanent feature of the language.  I
can't label them "experimental" forever.

- New extension modules cStringIO.c and cPickle.c, written by Jim
Fulton and other folks at Digital Creations.  These are much more
efficient than their Python counterparts StringIO.py and pickle.py,
but don't support subclassing.  cPickle.c clocks up to 1000 times
faster than pickle.py.  The pickle.py module has been updated to make
it compatible with the new binary format that cPickle.c produces (by
default it produces the old all-ASCII format compatible with the old
pickle.py, still much faster than pickle.py; it can read both
formats).  A new helper module, copy_reg.py, is provided to register
extensions to the pickling code.  (These are now identical to the
release 0.3 from Digital Creations.)

- New (still experimental) Perl-style regular expression module,
re.py, which uses a new interface for matching as well as a new
syntax; the new interface avoids the thread-unsafety of the regex
interface.  This comes with a helper extension reopmodule.c and vastly
rewritten regexpr.c.  Most work on this was done by Jeffrey Ollie, Tim
Peters, and Andrew Kuchling.  See the documentation libre.tex.  In
1.5, the old regex module is still fully supported; in the future, it
will become obsolete.

- New string literal syntax for "raw strings".  Prefixing a string
literal with the letter r (or R) disables all escape processing in the
string; for example, r'\n' is a two-character string consisting of a
backslash followed by the letter n.  This combines with all forms of
string quotes.  An embedded quote prefixed with a backslash does not
terminate the string, but the backslash is still included in the
string; for example, r'\'' is a two-character string consisting of a
backslash and a quote.  Raw strings are also affectionately known as
Robin strings, after their inventor, Robin Friedrich.

- New project files for Developer Studio (Visual C++) 5.0 for Windows
NT (the old VC++ 4.2 Makefile is also still supported, but will
eventually be withdrawn due to its bulkiness).

- New extension module zlibmodule.c, interfacing to the free zlib
library (gzip compatible compression).  There's also a module gzip.py
which provides a higher level interface.  Written by Andrew Kuchling
and Jeremy Hylton.

- New tool: faqwiz -- the CGI script that is used to maintain the
Python FAQ (http://grail.cnri.reston.va.us/cgi-bin/faqw.py).  In
Tools/faqwiz.

- New tool: webchecker -- a simple extensible web robot that, when
aimed at a web server, checks that server for dead links.  Available
are a command line utility as well as a Tkinter based GUI version.  In
Tools/webchecker.  A simplified version of this program is dissected
in my article in O'Reilly's WWW Journal, the issue on Scripting
Languages (Vol 2, No 2); Scripting the Web with Python (pp 97-120).
Includes a parser for robots.txt files by Skip Montanaro.

- New small tools: cvsfiles.py (prints a list of all files under CVS
in a particular directory tree), treesync.py (a rather Guido-specific
script to synchronize two source trees, one on Windows NT, the other
one on Unix under CVS but accessible from the NT box), and logmerge.py
(sort a collection of RCS or CVS logs by date).  In Tools/scripts.

- The freeze script now also works under Windows (NT).  Another
feature allows the -p option to be pointed at the Python source tree
instead of the installation prefix.  This was loosely based on part of
xfreeze by Sam Rushing and Bill Tutt.

- A new regression test suite is provided, which tests most of the
standard and built-in modules.  The regression test is run by invoking
the script Lib/test/regrtest.py.  Barry Warsaw wrote the test harnass;
he and Roger Masse contributed most of the new tests.

- New standard dialog modules for Tkinter: tkColorChooser.py,
tkCommonDialog.py, tkMessageBox.py, tkFileDialog.py, tkSimpleDialog.py
These interface with the new Tk dialog scripts.  Contributed by
Fredrik Lundh.

- Tkinter.py: when the first Tk object is destroyed, it sets the
hiddel global _default_root to None, so that when another Tk object is
created it becomes the new default root.  Other miscellaneous
changes and fixes.

- Many new pieces of library documentation were contributed, mostly by
Andrew Kuchling.  Even cmath is now documented!  There's also a
chapter of the library manual, "libundoc.tex", which provides a
listing of all undocumented modules, plus their status (e.g. internal,
obsolete, or in need of documentation).  Also contributions by Sue
Williams, Skip Montanaro, and some module authors who succumbed to
pressure to document their own contributed modules :-).  Note that
printing the documentation now kills fewer trees -- the margins have
been reduced.

- I have started documenting the Python/C API.  Unfortunately this
project hasn't been completed yet.  It will be complete before the
final release of Python 1.5, though.

- The mimify.py module now has documentation, and includes functions
to handle the funny encoding you sometimes see in mail headers.

- The default module search path is now much saner.  Both on Unix and
Windows, it is essentially derived from the path to the executable
($PYTHONHOME can be used to override).  The value of $PYTHONPATH on
Windows is now inserted in front of the default path, like in Unix
(instead of overriding the default path).

- Support for Win32S (the 32-bit Windows API under Windows 3.1) is
basically withdrawn.  If it works for you, you're lucky.

- On Win32 platforms (Windows NT and 95), there's a new extension
module, msvcrt.c, which provides various low-level operations defined
in the Microsoft Visual C++ Runtime Library.  These include locking(),
setmode(), get_osfhandle(), set_osfhandle(), and console I/O functions
like kbhit(), getch() and putch().

- The way GNU readline is configured is totally different.  The
--with-readline configure option is gone.  It is now an extension
module, which may be loaded dynamically.  You must enable it (and
specify the correct linraries to link with) in the Modules/Setup file.
Importing the module installs some hooks which enable command line
editing.  When the interpreter shell is invoked interactively, it
attempts to import the readline module; when this fails, the default
input mechanism is used.  The hook variables are PyOS_InputHook and
PyOS_ReadlineFunctionPointer.  (Code contributed by Lee Busby, with
ideas from William Magro.)

- New Unix extension module resource.c, by Jeremy Hylton, provides
access to getrlimit(), getrusage(), setrusage(), getpagesize(), and
related symbolic constants.

- Support for multiple independent interpreters.  See Doc/api.tex,
functions Py_NewInterpreter() and Py_EndInterpreter().  Since the
documentation is incomplete, also see the new Demo/pysvr example
(which shows how to use these in a threaded application) and the
source code.

- There is now a Py_Finalize() function which "de-initializes"
Python.  It is possible to completely restart the interpreter
repeatedly by calling Py_Finalize() followed by Py_Initialize().  A
change of functionality in Py_Initialize() means that it is now a
fatal error to call it while the interpreter is already initialized.
The old, half-hearted Py_Cleanup() routine is gone.  Use of Py_Exit()
is deprecated (it is nothing more than Py_Finalize() followed by
exit()).

- There are no known memory leaks.  While Py_Finalize() doesn't free
*all* allocated memory (some of it is hard to track down), repeated
calls to Py_Finalize() and Py_Initialize() do not create unaccessible
heap blocks.

- New function sys.exc_info() returns the tuple (sys.exc_type,
sys.exc_value, sys.exc_traceback) in a thread-safe way.

- The semantics of try-except have changed subtly so that calling a
function in an exception handler that itself raises and catches an
exception no longer overwrites the sys.exc_* variables.  This also
alleviates the problem that objects referenced in a stack frame that
caught an exception are kept alive until another exception is caught
-- the sys.exc_* variables are restored to their previous value when
returning from a function that caught an exception.

- There is now explicit per-thread state.  (Inspired by, but not the
same as, Greg Stein's free threading patches.)

- There is now better support for threading C applications.  There are
now explicit APIs to manipulate the interpreter lock.  Read the source
or the Demo/pysvr example; the new functions are
PyEval_{Acquire,Release}{Lock,Thread}().

- New wrappers around malloc() and friends: Py_Malloc() etc. call
malloc() and call PyErr_NoMemory() when it fails; PyMem_Malloc() call
just malloc().  Use of these wrappers could be essential if multiple
memory allocators exist (e.g. when using certain DLL setups under
Windows).  (Idea by Jim Fulton.)

- Numerous source cleanups.

- There's a simple assert statement, and a new exception
AssertionError, and a built-in variable __debug__.  For example,
``assert foo > 0'' is equivalent to ``if __debug__ and not foo > 0:
raise AssertionError''.  Sorry, the text of the asserted condition is
not available; it would be too generate code for this.  However, the
text is displayed as part of the traceback!  There's also a -O option
to the interpreter that squeezes SET_LINENO instructions, assert
statements and ``if __debug__'' code; it uses and produces .pyo files
instead of .pyc files.  In the future it should be possible to write
external bytecode optimizers that create better optimized .pyo files.

- New build procedure: a single library, libpython1.5.a, is now built,
which contains absolutely everything except for a one-line main()
program (which calls Py_Main(argc, argv) to start the interpreter
shell).  This makes life much simpler for applications that need to
embed Python.  The serial number of the build is now included in the
version string (sys.version).

- New module keyword.py exports knowledge about Python's built-in
keywords.  (New version by Ka-Ping Yee.)

- New examples (Demo/extend) that show how to use the generic
extension makefile (Misc/Makefile.pre.in).

- New module pprint.py (with documentation) which supports
pretty-printing of lists, tuples, & dictionaries recursively.  By Fred
Drake.

- New module code.py.  The function code.compile_command() can
determine whether an interactively entered command is complete or not,
distinguishing incomplete from invalid input.

- Module codehack.py is now completely obsolete.

- Revamped module tokenize.py is much more accurate and has an
interface that makes it a breeze to write code to colorize Python
source code.  Contributed by Ka-Ping Yee.

- As always, the Macintosh port was done by Jack Jansen.  See his
separate announcement for the Mac specific source code and the binary
distribution(s).

- A set of patches from Lee Busby has been integrated that make it
possible to catch floating point exceptions.  Use the configure option
--with-fpectl to enable the patches; the extension modules fpectl and
fpetest provide control to enable/disable and test the feature,
respectively.

- New extension puremodule.c, by Barry Warsaw, which interfaces to the
Purify(TM) C API.  See also the file Misc/PURIFY.README.  It is also
possible to enable Purify by simply setting the PURIFY Makefile
variable in the Modules/Setup file.

- The struct extension module has several new features to control byte
order and word size.  It supports reading and writing IEEE floats even
on platforms where this is not the native format.

- There is now a library module xdr.py which can read and write the
XDR data format as used by Sun RPC, for example.  It uses the struct
module.

- Tools/scripts/h2py.py now supports C++ comments.

- The pystone.py script is upgraded to version 1.1; there was a bug in
version 1.0 (distributed with Python 1.4) that leaked memory.  Also,
in 1.1, the LOOPS variable is incremented to 10000.

- New C API PyImport_Import() which uses whatever __import__() hook
that is installed for the current execution environment.  By Jim
Fulton.

- The _tkinter.c extension module has been revamped.  It now support
Tk versions 4.1 through 8.0; support for 4.0 has been dropped.  It
works well under Windows and Mac (with the latest Tk ports to those
platforms).  It also supports threading -- it is safe for one
(Python-created) thread to be blocked in _tkinter.mainloop() while
other threads modify widgets.  (To make the changes visible, those
threads must use update_idletasks()method.)  Unfortunately, on Windows
and Mac, Tk 8.0 no longer supports CreateFileHandler, so
_tkinter.createfilehandler is not available on those platforms.  I
will have to rethink how to interface with Tcl's lower-level event
mechanism, or with its channels (which are like Python's file-like
objects).

- New "buffer" interface.  Certain objects (e.g. strings, arrays) now
support the "buffer" protocol.  Buffer objects are acceptable whenever
formerly a string was required for a write operation; mutable buffer
objects can be the target of a read operation using the
f.readinto(buffer).  Contribution bty Jack Jansen.  (Needs
documentation.)

- In ihooks.py, ModuleLoader.load_module() now closes the file under
all circumstances.

- The tempfile.py module has a new class, TemporaryFile, which creates
an open temporary file that will be deleted automatically when
closed.  This works on Windows and MacOS as well as on Unix.  (Jim
Fulton.)

- Changes to the cgi.py module: Most imports are now done at the
top of the module, which provides a speedup when using ni (Jim
Fulton).  The problem with file upload to a Windows platform is solved
by using the new tempfile.TemporaryFile class; temporary files are now
always opened in binary mode (Jim Fulton).  The cgi.escape() function
now takes an optional flag argument that quotes '"' to '"'.  It
is now possible to invoke cgi.py from a command line script, to test
cgi scripts more easily outside an http server.  There's an optional
limit to the size of uploads to POST (Skip Montanaro).  Added a
'strict_parsing' option to all parsing functions (Jim Fulton).  The
function parse_qs() now uses urllib.unquote() on the name as well as
the value of fields (Clarence Gardner).

- String interning: dictionary lookups are faster when the lookup
string object is the same object as the key in the dictionary, not
just a string with the same value.  This is done by having a pool of
"interned" strings.  Most names generated by the interpreter are now
automatically interned, and there's a new built-in function intern(s)
that returns the interned version of a string.  Interned strings are
not a different object type, and interning is totally optional, but by
interning most keys a speedup of about 15% was obtained for the
pystone benchmark.

- httplib.py: the socket object is no longer closed; all HTTP/1.*
versions are now treated the same; and it is now thread-safe (by not
using the regex module).

- BaseHTTPModule.py: treat all HTTP/1.* versions the same.

- The popen2.py module is now rewritten using a class, which makes
access to the standard error stream and the process id of the
subprocess possible.

- The support for shared libraries under AIX is now simpler and more
robust.  Thanks to Vladimir Marangozov for revamping his own patches!

- When a module is deleted, its globals are now deleted in two phases.
In the first phase, all variables whose name begins with exactly one
underscore are replaced by None; in the second phase, all variables
are deleted.  This makes it possible to have global objects whose
destructors depend on other globals.  The deletion order within each
phase is still random.

- The Modules/makesetup script now reads a file Setup.local as well as
a file Setup.  Most changes to the Setup script can be done by editing
Setup.local instead, which makes it easier to carry a particular setup
over from one release to the next.

- It is no longer an error for a function to be called without a
global variable __builtins__ -- an empty directory will be provided
by default.

- Some speedup by using separate free lists for method objects (both
the C and the Python variety) and for floating point numbers.

- Big speedup by allocating frame objects with a single malloc() call.
The Python/C API for frames is changed (you shouldn't be using this
anyway).

- It is now possible for an extension module's init function to fail
non-fatally, by calling one of the PyErr_* functions and returning.

- The PyInt_AS_LONG() and PyFloat_AS_DOUBLE() macros now cast their
argument to the proper type, like the similar PyString macros already
did.  (Suggestion by Marc-Andre Lemburg.)

- The fcntl extension module now exports the needed symbolic
constants.  (Formerly these were in FCNTL.py which was not available
or correct for all platforms.)

- Guido's corollary of the Don Beaudry hack: it is now possible to do
metaprogramming by using an instance as a base class.  Not for the
faint of heart; and undocumented as yet, but basically if a base class
is an instance, its class will be instantiated to create the new
class.  Jim Fulton will love it -- it also works with instances of his
"extension classes", since it is triggered by the presence of a
__class__ attribute on the purported base class.

- Plugged the two-byte memory leak in the tokenizer when reading an
interactive EOF.

- Added timezone support to the rfc822.py module; also added
recognition of some non-standard date formats, by Lars Wirzenius.

- mhlib.py: various enhancements, including almost compatible parsing
of message sequence specifiers without invoking a subprocess.  Also
added a createmessage() method by Lars Wirzenius.

- The StringIO.StringIO class now supports readline(nbytes).  (Lars
Wirzenius.)

- Dictionary objects have several new methods; clear() and copy() have
the obvious semantics, while update(d) merges the contents of another
dictionary d into this one, overriding existing keys.  BTW, the
dictionary implementation file is now called dictobject.c rather than
the confusing mappingobject.c.

- UserDict.py supports the new dictionary methods as well.

- The intrinsic function dir() is much smarter; it looks in __dict__,
__members__ and __methods__.

- The silly -s command line option and the corresponding
PYTHONSUPPRESS environment variable and the Py_SuppressPrint global
flag are gone.

- On Windows, -u not only sets the standard I/O streams to unbuffered
status, but also sets them in binary mode.

- Some of the Py_Get* function, like Py_GetVersion() (but not yet
Py_GetPath()) are now declared as returning a const char *.  (More
should follow.)

- Speedup by inlining some common opcodes for common operand types
(e.g. i+i, i-i, and list[i]).  Fredrik Lundh.

- The extension modules dbm, gdbm and bsddb now check that the
database is still open before making any new calls.

- Various small fixes to the nntplib.py module that I can't bother to
document in detail.

- There is a cache for results in urlparse.urlparse(); its size limit
is set to 20 (not 2000 as it was in earlier alphas).

- Small speedup by reordering the method tables of some common
objects (e.g. list.append is now first).

- The modules base64.py, uu.py and quopri.py can now be used as simple
command line utilities.

- The binascii extension module is now hopefully fully debugged.  (XXX
Oops -- Fredril Lundh promised me a fix that I never received.)

- The mimetools.py module now uses the available Python modules for
decoding quoted-printable, uuencode and base64 formats, rather than
creating a subprocess.

- The python debugger (pdb.py, and its base class bdb.py) now support
conditional breakpoints.  See the docs.

- The configure script now detects whether malloc(0) returns a NULL
pointer or a valid block (of length zero).  This avoids the nonsense
of always adding one byte to all malloc() arguments on most platforms.

- Improvements for whrandom.py by Tim Peters: use 32-bit arithmetic to
speed it up, and replace 0 seed values by 1 to avoid degeneration.

- Fix a bug where multiple anonymous tuple arguments would be mixed up
when using the debugger or profiler (reported by Just van Rossum).
The simplest example is ``def f((a,b),(c,d)): print a,b,c,d''; this
would print the wrong value when run under the debugger or profiler.

- Module ftplib.py: added support for parsing a .netrc file.  Fred
Drake.

- urllib.py: the ftp cache is now limited to 10 entries.  Added
quote_plus() method which is like qupte() but also replaces spaces
with '+', for encoding CGI form arguments.  Catch all errors from the
ftp module.  HTTP requests now add the Host: header line.  The proxy
variable names are now mapped to lower case, for Windows.

- The posix module (and hence os.py!) now has doc strings!  Thanks to
Neil Schemenauer.

- shelve.py: use cPickle and cStringIO when available.

- Various modules now export their type object: socket.SocketType,
array.ArrayType.

- ntpath.py supports ~ to $HOME expansion in expanduser().

- The pthread support now works on most platforms.

- New variable sys.executable points to the executable file for the
Python interpreter, if known.

- On Windows, sys.prefix and sys.exec_prefix point to the directory
where Python is installed, or to the top of the source tree, if it was
run from there.

- The sort() methods for lists no longer uses the C library qsort(); I
wrote my own quicksort implementation, with help from Tim Peters.
This solves a bug in dictionary comparisons on some Solaris versions
when Python is built with threads, and makes sorting lists even
faster.

- STDWIN is now officially obsolete.  Support for it will eventually
be removed from the distribution.

- The configure script is smarter about C compiler options; e.g. with
gcc it uses -O2 and -g when possible, and on some other platforms it
uses -Olimit 1500 to avoid a warning from the optimizer about the main
loop in ceval.c (which has more than 1000 basic blocks).

- Changed the run-time library to check for exceptions after object
comparisons.  PyObject_Compare() can now return an exception; use
PyErr_Occurred() to check (there is *no* special return value).

- PyFile_WriteString() and Py_Flushline() now return error indicators
instead of clearing exceptions.  This fixes an obscure bug where using
these would clear a pending exception, discovered by Just van Rossum.

- Most problems on 64-bit platforms should now be fixed.  Andrew
Kuchling helped.  Some uncommon extension modules are still not
clean (image and audio ops?).