path: root/README

This is Python release 1.2
==========================


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

This version provides new functionality as well as bug fixes, lots of
new documentation, and quite a few new library modules.  Everyone
should upgrade.  For a full list of what's new and changed, see
Misc/NEWS.


What is Python anyway?
----------------------

Python is an interpreted object-oriented programming language, and is
often compared to Tcl, Perl or Scheme.  For a quick summary of what
Python can mean for a UNIX/C programmer, read Misc/BLURB.LUTZ.


If you don't read instructions
------------------------------

Congratulations on getting this far. :-)

To start building right away (on UNIX): type "./configure" in the
current directory and when it finishes, type "make".  The section
Build Instructions below is still recommended reading. :-)


Copyright issues
----------------

Python is COPYRIGHTED but free to use for all.  See the full copyright
notice at the end of this file.

The Python distribution is *not* affected by the GNU Public Licence
(GPL).  There are interfaces to some GNU code but these are entirely
optional and no GNU code is distributed with Python.  For all these
packages, GPL-free public domain versions also exist.



Build instructions
==================

Before you start building Python, you must first configure it.  This
entails (at least) running the script "./configure", which figures out
your system configuration and creates several Makefiles.  (It takes a
minute or two -- please be patient!)  When it's done, you are ready to
run make.  Typing "make" in the toplevel directory will recursively
run make in each of the subdirectories Parser, Objects, Python and
Modules, creating a library file in each one.  The executable of the
interpreter is built in the Modules subdirectory and moved up here
when it is built.  If you want or need to, you can also chdir into
each subdirectory in turn and run make there manually (do the Modules
subdirectory last!).

NOTE: if you rerun the configure script with different options, remove
all object files by running "make clean" before rebuilding.  Believe
it or not, "make clean" sometimes helps to clean up other inexplicable
problems as well.  Try it before sending in a bug report!


Troubleshooting
---------------

If you run into trouble, see section 3 of the FAQ (file Misc/FAQ) for
hints on what can go wrong, and how to fix it.


Platform specific notes
-----------------------

Linux:	It is possible that "makesetup" fails with an obscure sed
	error.  This is a bug in bash.  Replace /bin/sh with /bin/ash
	in both makesetup and Makefile.pre.in.  This has been observed
	in Slackware version 2.2, bash 1.14.3; Slackware 2.1 did not
	have the problem.

AIX:	Read the file Misc/AIX-NOTES before trying to build.

HP-UX:	Read the file Misc/HPUX-NOTES if you want to be able to
	use shared libraries for dynamically loaded modules.

Minix:	When using ack, use "CC=cc AR=aal RANLIB=: ./configure"!

SCO:	1) Everything works much better if you add -U__STDC__ to the
	defs.  This is because all the SCO header files are broken.
	Anything that isn't mentioned in the C standard it's
	conditionally excluded when __STDC__ is defined.

	2) Due to the U.S. export restrictions, SCO broke the crypt
	stuff out into a separate library, libcrypt_i.a so the LIBS
	needed be set to:

		LIBS=' -lsocket -lcrypt_i'


Configuring the set of built-in modules
---------------------------------------

You can configure the interpreter to contain fewer or more built-in
modules by editing the file Modules/Setup.  This file is initially
copied (when the toplevel Makefile makes Modules/Makefile for the
first time) from Setup.in; if it does not exist yet, make a copy
yourself.  Never edit Setup.in -- always edit Setup.  Read the
comments in the file for information on what kind of edits you can
make.  When you have edited Setup, Makefile and config.c in Modules
will automatically be rebuilt the next time you run make in the
toplevel directory.

Especially on SGI IRIX, there are modules that interface to many SGI
specific system libraries, e.g. the GL library and the audio hardware.


Setting the optimization/debugging options
------------------------------------------

If you want to change the optimization/debugging options for the C
compiler, assign to the OPT variable on the toplevel make command;
e.g. "make OPT=-g" will build a debugging version of Python on most
platforms.  The default is OPT=-O; a value for OPT in the environment
when the configure script is run overrides this default (likewise for
CC; and the initial value for LIBS is used as the base set of
libraries to link with).


Testing
-------

To test the interpreter that you have just built, type "make test".
This runs the test set silently, twice (once with no compiled files,
once with the compiled files left by the previous test run).  Each
test run should print "All tests OK." and nothing more.  (The test set
does not test the built-in modules, but will find most other problems
with the interpreter.)

IMPORTANT: If the tests fail and you decide to mail a bug report,
*don't* include the output of "make test".  It is useless.  Run the
following command instead:

	PYTHONPATH=../Lib:../Lib/test:./Modules ./python -c 'import testall'

(substituting the top of the source tree for .. if you built in a
different directory).  This gives the output of the tests and shows
which test failed.


Installing
----------

To install the interpreter as /usr/local/bin/python, type "make
install".  To install the library as /usr/local/lib/python, type "make
libinstall".  To install the manual page as
/usr/local/man/man1/python.1, type "make maninstall".  To install the
Emacs editing mode for python, manually copy the file
Misc/python-mode.el to your local Emacs lisp directory.  The directory
/usr/local can be overridden at configuration time by passing
--prefix=DIRECTORY to the configure script, or at make time by passing
"prefix=DIRECTORY" to make.  See below for more information on --prefix.

If you plan to do development of extension modules or to embed Python
in another application and don't want to reference the original source
tree, you can type "make inclinstall" and "make libainstall" to
install the include files and lib*.a files, respectively, as
/usr/local/include/Py/*.h and /usr/local/lib/python/lib/lib*.a.  The
make libainstall target also installs copies of several other files
used or produced during the build process which are needed to build
extensions or to generate their Makefiles.


Configuration options and variables
-----------------------------------

Some special cases are handled by passing environment variables or
options to the configure script.

NOTE: if you rerun the configure script with different options, remove
all object files by running "make clean" before rebuilding.

--with(out)-gcc: The configure script uses gcc (the GNU C compiler) if
	it finds it.  If you don't want this, or if this compiler is
	installed but broken on your platform, pass the option
	--without-gcc.  You can also pass "CC=cc" (or whatever the
	name of the proper C compiler is) in the environment, but the
	advantage of using --without-gcc is that this option is
	remembered by the config.status script for its --recheck
	option.

--prefix, --exec-prefix: If you want to install the binaries and the
	Python library somewhere else than in /usr/local/{bin,lib},
	you can pass the option --prefix=DIRECTORY; the interpreter
	binary will be installed as DIRECTORY/bin/python and the
	library files as DIRECTORY/lib/python/*.  If you pass
	--exec-prefix=DIRECTORY (as well) this overrides the
	installation prefix for architecture-dependent files (like the
	interpreter binary).  Note that --prefix=DIRECTORY also
	affects the default module search path (sys.path), when
	Modules/config.c is compiled.  Passing make the option
	prefix=DIRECTORY (and/or exec_prefix=DIRECTORY) overrides the
	prefix set at configuration time; this may be more convenient
	than re-running the configure script if you change your mind
	about the install prefix...

--with-readline: You can use the GNU readline library to improve the
	interactive user interface: this gives you line editing and
	command history when calling python interactively.  You need
	to configure build the GNU readline library before running the
	configure script.  Its sources are not distributed with
	Python; you can ftp them from any GNU mirror site, or from its
	home site:
	<URL:ftp://slc2.ins.cwru.edu/pub/dist/readline-2.0.tar.gz> (or
	a higher version number -- using version 1.x is not
	recommended).

	A GPL-free version was posted to comp.sources.misc in volume
	31 and is widely available from FTP archive sites, e.g.
	<URL:ftp://gatekeeper.dec.com/.b/usenet/comp.sources.misc/
	volume31/editline/part01.Z>

	Pass the Python configure script the option
	--with-readline=DIRECTORY where DIRECTORY is the absolute
	pathname of the directory where you've built the readline
	library.  Some hints on building and using the readline
	library are in the FAQ (file Misc/FAQ).

--with-thread: On SGI IRIX, and on Sun SOLARIS 2, you can use multiple
	threads.  To enable this, pass --with-thread.  In the
	Modules/Setup file, enable the thread module.  (Threads aren't
	enabled automatically because there are run-time penalties
	when support for them is compiled in even if you don't use
	them.)

--with-sgi-dl: On SGI IRIX 4, dynamic loading of extension modules is
	supported by the "dl" library by Jack Jansen, which is
	ftp'able from <URL:ftp://ftp.cwi.nl/pub/dynload/dl-1.6.tar.Z>.
	This is enabled (after you've ftp'ed and compiled the dl
	library!) by passing --with-sgi-dl=DIRECTORY where DIRECTORY
	is the absolute pathname of the dl library.  (Don't bother on
	IRIX 5, it already has dynamic linking using SunOS style
	shared libraries.)  Support for this feature is deprecated.

--with-dl-dld: Dynamic loading of modules is rumoured to be supported
	on some other systems: VAX (Ultrix), Sun3 (SunOS 3.4), Sequent
	Symmetry (Dynix), and Atari ST.  This is done using a
	combination of the GNU dynamic loading package
	(<URL:ftp://ftp.cwi.nl/pub/dynload/dl-dld-1.1.tar.Z>) and an
	emulation of the SGI dl library mentioned above (the emulation
	can be found at
	<URL:ftp://ftp.cwi.nl/pub/dynload/dld-3.2.3.tar.Z>).  To
	enable this, ftp and compile both libraries, then call the
	configure passing it the option
	--with-dl-dld=DL_DIRECTORY,DLD_DIRECTORY where DL_DIRECTORY is
	the absolute pathname of the dl emulation library and
	DLD_DIRECTORY is the absolute pathname of the GNU dld library.
	(Don't bother on SunOS 4 or 5, they already have dynamic
	linking using shared libraries.)  Support for this feature is
	deprecated.

--with-libm, --with-libc: It is possible to specify alternative
	versions for the Math library (default -lm) and the C library
	(default the empty string) using the options
	--with-libm=STRING and --with-libc=STRING, respectively.  E.g.
	if your system requires that you pass -lc_s to the C compiler
	to use the shared C library, you can pass --with-libc=-lc_s.
	These libraries are passed after all other libraries, the C
	library last.


Extensions
----------

You can also build an "extended" interpreter, using modules that are
not contained in the Modules directory.  Extensions are distributed as
a separate tar file (currently extensions.tar.gz).  See the README
file there.


Building for multiple architectures (using the VPATH feature)
-------------------------------------------------------------

If your file system is shared between multiple architectures, it
usually is not necessary to make copies of the sources for each
architecture you want to support.  If the make program supports the
VPATH feature, you can create an empty build directory for each
architecture, and in each directory run the configure script (on the
appropriate machine with the appropriate options).  This creates the
necessary subdirectories and the Makefiles therein.  The Makefiles
contain a line VPATH=... which points to directory containing the
actual sources.  (On SGI systems, use "smake" instead of "make" if you
use VPATH -- don't try gnumake.)

For example, the following is all you need to build a minimal Python
in /usr/tmp/python (assuming ~guido/src/python is the toplevel
directory and you want to build in /usr/tmp/python):

	$ mkdir /usr/tmp/python
	$ cd /usr/tmp/python
	$ ~guido/src/python/configure
	[...]
	$ make
	[...]
	$

Note that Modules/Makefile copies the original Setup file to the build
directory if it finds no Setup file there.  This means that you can
edit the Setup file for each architecture independently.  For this
reason, subsequent changes to the original Setup file are not tracked
automatically, as they might overwrite local changes.  To force a copy
of a changed original Setup file, delete the target Setup file.  (The
makesetup script supports multiple input files, so if you want to be
fancy you can change the rules to create an empty Setup.local if it
doesn't exist and run it with arguments $(srcdir)/Setup Setup.local;
however this assumes that you only need to add modules.)


Building on non-UNIX systems
----------------------------

On non-UNIX systems, you will have to fake the effect of running the
configure script manually.  A good start is to copy the file
config.h.in to config.h and edit the latter to reflect the actual
configuration of your system.  Most symbols must simply be defined as
1 only if the corresponding feature is present and can be left alone
otherwise; however RETSIGTYPE must always be defined, either as int or
as void, and the *_t type symbols must be defined as some variant of
int if they need to be defined at all. Then arrange that the symbol
HAVE_CONFIG_H is defined during compilation (usually by passing an
argument of the form `-DHAVE_CONFIG_H' to the compiler, but this is
necessarily system-dependent).

I have tried to collect instructions, Makefiles and additional sources
for various platforms in this release.  The following directories
exist:

Mac/		Apple Macintosh, using THINK C 6.0 or MPW 3.2.
Dos/		MS-DOS and Windows 3.1, using Microsoft C.
Nt/		Windows NT, using Microsoft Visual C/C++.
Os2/		OS/2.

Most of these instructions were last tested with a previous Python
release, so you may still experience occasional problems.  If you have
fixes or suggestions, please let me know and I'll try to incorporate
them in the next release.



Miscellaneous issues
====================


Documentation
-------------

All documentation is provided in the subdirectory Doc in the form of
LaTeX files.  In order of importance for new users: Tutorial (tut),
Library Reference (lib), Language Reference (ref), Extending (ext).
Especially the Library Reference is of immense value since much of
Python's power (including the built-in data types and functions!) is
described here.

To print the documentation from the LaTeX files, chdir into the Doc
subdirectory, type "make" (let's hope you have LaTeX installed!), and
send the four resulting PostScript files (tut.ps, lib.ps, ref.ps, and
ext.ps) to the printer.  See the README file there.

All documentation is also available on-line via the World-Wide Web
(WWW): <URL:http://www.cwi.nl/~guido/Python.html>.  It can also be
downloaded separately from the ftp archives (see below) in Emacs INFO,
HTML or PostScript form -- see the FAQ (file Misc/FAQ) for more info.


Emacs mode
----------

There's an excellent Emacs editing mode for Python code; see the file
Misc/python-mode.el.  Originally written by Tim Peters, who's no
longer on the net, it is now maintained by Barry Warsaw
<bwarsaw@cnri.reston.va.com>.


Bug reports
-----------

Bugs are best reported to the comp.lang.python newsgroup or the Python
mailing list -- see the section "Newsgroup and mailing list" below.
Before posting, read the FAQ (file Misc/FAQ) first to see if your
problem has already been answered!


Ftp access
----------

Python's "home ftp site" is ftp.cwi.nl, directory pub/python.  See the
FAQ (file Misc/FAQ) for a list of other ftp sites carrying the Python
distribution.


Newsgroup and mailing list
--------------------------

There are a newsgroup and a mailing list devoted to Python
programming, design and bugs.  The newsgroup, comp.lang.python,
contains exactly the same messages as the mailing list.  To subscribe
to the mailing list, send mail containing your real name and e-mail
address to "python-list-request@cwi.nl" (a real person reads these
messages, so no LISTPROC or Majordomo commands, please).


The Tk interface
----------------

Tk (the user interface component of John Ousterhout's Tcl language) is
also usable from Python.  Since this requires that you first build and
install Tcl/Tk, the Tk interface is not enabled by default.  It
requires Tcl 7.3 and Tk 3.6.  It doesn't work yet with Tk 4.0-beta!
(Actually, the C code does, but the Tkinter.py module hasn't been
adapted yet.)  For more info about Tk, including pointers to the
source, see John Ousterhout's home page at
<URL:http://playground.sun.com/~ouster/>.

To enable the Python/Tk interface, once you've built and installed
Tcl/Tk, all you need to do is edit two lines in Modules/Setup; search
for the string "tkinter".  Un-comment one (normally the first) of the
lines beginning with "#tkinter" and un-comment the line beginning with
"#TKPATH".  (If you have installed Tcl/Tk in unusual places you will
have to edit the first line as well to fix the -I and -L options.)
See the Build Instructions above for more details.

There is little documentation.  Begin with fetching the "Tk Lifesaver"
document, e.g. <URL:ftp://ftp.cwi.nl/pub/python/tkinter-doc.tar.gz> (a
gzipped tar file containing a PostScript file).  There are demos in
the Demo/tkinter directory, in the subdirectories guido, matt and www.

Note that there's a Python module called "Tkinter" (capital T) which
lives in Lib/tkinter/Tkinter.py, and a C module called "tkinter"
(lower case t) which lives in Modules/tkintermodule.c.  Demos and
normal Tk applications only import the Python Tkinter module -- only
the latter uses the C tkinter module directly.  In order to find the C
tkinter module, it must be compiled and linked into the Python
interpreter -- the tkinter line in the Setup file does this.  In order
to find the Python Tkinter module, sys.path must be set correctly --
the TKPATH assignment in the Setup file takes care of this, but only
if you install Python properly ("make install libinstall").  (You can
also use dynamic loading for the C tkinter module, in which case you
must manually fix up sys.path or set $PYTHONPATH for the Python
Tkinter module.)


Distribution structure
----------------------

Most subdirectories have their own README file.  Most files have
comments.

ChangeLog	A raw list of changes since the first 1.0.0 BETA release
Contrib/	Interesting or useful Python code contributed by others
Demo/		Demonstration scripts, modules and programs
Doc/		Documentation (LaTeX sources)
Extensions/	Extension modules (distributed separately)
Grammar/	Input for the parser generator
Include/	Public header files
Lib/		Python library modules
Makefile.in	Source from which config.status creates Makefile
Misc/		Miscellaneous files
Modules/	Implementation of most built-in modules
Objects/	Implementation of most built-in object types
Parser/		The parser and tokenizer and their input handling
Python/		The "compiler" and interpreter
README		The file you're reading now
Tools/		Some useful programs written in Python
acconfig.h	Additional input for the autoheader program
config.h.in	Source from which config.status creates config.h
configure	Configuration shell script (GNU autoconf output)
configure.in	Configuration specification (GNU autoconf input)

The following files will (may) be created in the toplevel directory by
the configuration and build processes:

Makefile	Build rules
config.cache	cache of configuration variables
config.h	Configuration header
config.log	log from last configure run
config.status	status from last run of configure script
python		The executable interpreter
tags, TAGS	Tags files for vi and Emacs


Author's address
----------------

Guido van Rossum
CWI, dept. CST
P.O. Box 94079
1090 GB  Amsterdam
The Netherlands

E-mail: guido@cwi.nl



Copyright notice
================

The Python source is copyrighted, but you can freely use and copy it
as long as you don't change or remove the copyright notice:

----------------------------------------------------------------------
Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
The Netherlands.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation, and that the names of Stichting Mathematisch
Centrum or CWI not be used in advertising or publicity pertaining to
distribution of the software without specific, written prior permission.

STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO
THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE
FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
----------------------------------------------------------------------


--Guido van Rossum, CWI, Amsterdam <mailto:guido@cwi.nl>
<http://www.cwi.nl/~guido/>