This is Python release 1.5 alpha 3 ================================== ****************************************** *** RELEASE RESTRICTED TO PSA MEMBERS! *** ****************************************** What's new in this release? --------------------------- Too much has changed to list it all; I'll be more complete later. The most important changes since Python 1.4 include: - Many previously undocumented modules are now documented; some are now officially obsolete or deprecated. - It's much faster (almost twice for pystone.py -- see Tools/scripts.) - There's an assert statement. - There's a -O option that removes SET_LINENO instructions and code prefixed with ``if __debug__: ...''. - It's much smarter about the initial value for sys.path; you can control it easier using $PYTHONHOME (see the usage message, e.g. try ``python -h''). - The Grand Renaming is completed: all linker-visible symbols defined by Python now have a "Py" or "_Py" prefix, and the same is true for most macros and typedefs. - The build strategy now uses a single library (libpython1.5.a) which contains everything except for the main() entry point. This makes life much easier for applications that want to embed Python. - There is also much better support for embedding Python in applications that use threads. - Unfinished projects: documentation; multiple independent interpreters; more Windows support. What is Python anyway? ---------------------- Python is an interpreted object-oriented programming language, and is often compared to Tcl, Perl, Java or Scheme. For a quick summary of what Python can mean for a UNIX/C programmer, read Misc/BLURB.LUTZ. If you have web access, point your browser to http://www.python.org. How do I learn Python? ---------------------- The official tutorial is still a good place to start (in the Doc directory as tut.tex; and http://www.python.org/doc/tut/tut.html). Aaron Watters wrote a second tutorial, that may be more accessible for some: http://www.wcmh.com/uworld/archives/95/tutorial/005.html. There are now also several books on Python. While these are still based on Python 1.3 or 1.4, the language is so stable now that you'd be hard pressed to find places where the books are out of date. The first two books, both first published in October 1996 and both including a CD-ROM, form excellent companions to each other: Internet Programming with Python by Aaron Watters, Guido van Rossum, and James Ahlstrom MIS Press/Henry Holt publishers ISBN: 1-55851-484-8 Programming Python by Mark Lutz O'Reilly & Associates ISBN: 1-56592-197-6 If you prefer to read German, try: Das Python-Buch by Martin von Loewis and Nils Fischbeck Addison-Wesley-Longman, 1997 ISBN: 3-8273-1110-1 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. A modest plug ============= ********************************************************************* * Without your help, I won't be able to continue to support Python! * ********************************************************************* If you use Python, please consider joining the Python Software Activity (PSA). See http://www.python.org/psa/. Organizations that make heavy use of Python are especially encouraged to become corporate members! Build instructions ================== Before you can build Python, you must first configure it. Fortunately, the configuration and build process has been streamlined for most Unix installations, so all you have to do is type a few commands, optionally edit one file, and sit back. There are some platforms where things are not quite as smooth; see the platform specific notes below. If you want to build for multiple platforms sharing the same source tree, see the section on VPATH below. You start by 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. You may want to pass options to the configure script -- see the section below on configuration options and variables. To build Python, you normally type "make" in the toplevel directory. This 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!). Once you have built an interpreter, see the subsections below on testing, configuring additional modules, and installation. If you run in trouble, see the next section. Troubleshooting --------------- See also the platform specific notes in the next section. If recursive makes fail, try invoking make as "make MAKE=make". If you run into other trouble, see section 3 of the FAQ (file Misc/FAQ) for hints on what can go wrong, and how to fix it. 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! If the configure script fails or doesn't seem to find things that should be there, inspect the config.log file. Platform specific notes ----------------------- (Some of these may no longer apply. If you find you can build Python on these platforms without the special directions mentioned here, let me know so I can remove them!) Solaris: When using Sun's C compiler with threads, at least on Solaris 2.5.1, you need to add the "-mt" compiler option (the simplest way is probably to specify the compiler with this option as the "CC" environment variable when running the configure script). Linux: On Linux version 1.x, once you've built Python, use it to run the regen script in the Lib/linux1 directory. Apparently the files as distributed don't match the system headers on some Linux versions. (The "h2py" command refers to Tools/scripts/h2py.py.) The modules distributed for Linux 2.x should be okay. Shared library support now works by default on ELF-based x86 Linux systems. (Note: when you change the status of a module from static to shared, you must remove its .o file or do a "make clean".) DEC Unix: When enabling threads, use --with-dec-threads, not --with-thread. AIX: A complete overhaul of the shared library support is now in place. To enable it, uncomment the LINKCC line in the Setup file. See Misc/AIX-NOTES for some notes on how it's done. WARNING! In some versions of AIX, you get errors about Invalid Indent when running the Python test set. This appears to be a bug in the AIX compiler. Rebuild Parser/tokenizer.c using OPT="" or OPT=-g, or use gcc. According to the latest reports, it seems this compiler bug is still present in 4.2.1. HP-UX: Shared library support now works by default (at least on HP-UX 9.x). One other problem remains: the HP ANSI C compiler (cc -Aa) is too pedantic to use, but in K&R mode, it barfs on a few files (complexobject.c, getargs.c and operator.c). Until this is fixed, the following seems to work: make -k # this compiles all but a few files make OPT=-Aa # compile the remaining files 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' 3) According to at least one report, the above apply only to SCO 3 -- Python builds out of the box on SCO 5. SunOS: On SunOS 4.1.x, when using the SunPro C compiler, you may want to use the '-Xa' option instead of '-Xc', to enable some needed non-ANSI Sunisms. NeXT: To build fat binaries, use the --with-next-archs switch described below. Configuring additional 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. (When working inside the Modules directory, use "make Makefile; make".) The default collection of modules should build on any Unix system, but many optional modules should work on all modern Unices (e.g. try dbm, nis, termios, timing, syslog, curses, new, soundex, parser). Often the quickest way to determine whether a particular module works or not is to see if it will build: enable it in Setup, then if you get compilation or link errors, disable it -- you're missing support. On SGI IRIX, there are modules that interface to many SGI specific system libraries, e.g. the GL library and the audio hardware. For SunOS and Solaris, enable module "sunaudiodev" to support the audio device. In addition to the file Setup, you can also edit the file Setup.local. (the makesetup script processes both). You may find it more convenient to edit Setup.local and leave Setup alone. Then, when installing a new Python version, you can copy your old Setup.local file. Setting the optimization/debugging options ------------------------------------------ If you want or need 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 twice (once with no compiled files, once with the compiled files left by the previous test run). The test set produces some output. You can generally ignore the messages about skipped tests due to an optional feature that can't be imported (if you want to test those modules, edit Modules/Setup to configure them). If a messages is printed about a failed test or a traceback or core dump is produced, something's wrong. On some systems, test_strftime fails due to a non-standard implementation of strftime() in the C library. This can be ignored (or you can complain to your vendor). 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 test that fails manually, as follows: python ../Lib/test/test_whatever.py (substituting the top of the source tree for .. if you built in a different directory). This runs the test in verbose mode. Installing ---------- Installing Python was never this easy! To install the Python binary, library modules, shared library modules (see below), include files, configuration files, and the manual page, just type "make install". This will install all platform-independent files in subdirectories the directory given with the --prefix option to configure or the 'prefix' Make variable (default /usr/local), and all binary and other platform-specific files in subdirectories if the directory given by --exec-prefix or the 'exec_prefix' Make variable (defaults to the --prefix directory). All subdirectories created will have Python's version number in their name, e.g. the library modules are installed in "/usr/local/lib/python1.5/" by default. The Python binary is installed as "python1.5" and a hard link named "python" is created. The only file not installed with a version number in its name is the manual page, installed as "/usr/local/man/man1/python.1" by default. If you have a previous installation of a pre-1.4 Python that you don't want to replace yet, use "make altinstall". This installs the same set of files as "make install" except it doesn't create the hard link to "python1.5" named "python" and it doesn't install the manual page at all. The only thing you may have to install manually is the Python mode for Emacs. (But then again, more recent versions of Emacs may already have it!) This is the file Misc/python-mode.el; follow the instructions that came with Emacs for installation of site specific files. Configuration options and variables ----------------------------------- Some special cases are handled by passing options to the configure script. WARNING: if you rerun the configure script with different options, you must run "make clean" before rebuilding. Exceptions to this rule: after changing --prefix or --exec-prefix, all you need to do is remove Modules/getpath.o. --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: This option is no longer supported. To use GNU readline, enable module "readline" in the Modules/Setup file. --with-thread: On most Unix systems, you can now use multiple threads. To enable this, pass --with-thread. (--with-threads is an alias.) If the library required for threads lives in a peculiar place, you can use --with-thread=DIRECTORY. NOTE: you must also enable the thread module by uncommenting it in the Modules/Setup file. (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.) IMPORTANT: run "make clean" after changing (either enabling or disabling) this option! Note: for DEC Unix use --with-dec-threads instead. --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 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 (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 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. --with-next-archs='arch1 arch2': Under NEXTSTEP, this will build all compiled binaries with the architectures listed. Includes correctly setting the target architecture specific resource directory. (This option is not supported on other platforms.) --with-libs='libs': Add 'libs' to the LIBS that the python linked against. 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 -J1" 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 ---------------------------- Building Python for a PC is now a piece of cake! Enter the directory "PC" and read the file "readme.txt". Most popular non-Unix PC platforms and compilers are supported (Unix ports to the PC such as Linux, FreeBSD or Solaris-x86 of course use the standard Unix build instructions). For the Mac, a separate source distribution will be made available, for use with the CodeWarrior compiler. If you are interested in Mac development, join the PythonMac Special Interest Group (http://www.python.org/sigs/pythonmac-sig/, or send email to pythonmac-sig-request@python.org). Of course, there are also binary distributions available for these platforms -- see http://www.python.org/python/. To port Python to a new non-UNIX system, you will have to fake the effect of running the configure script manually (for Mac and PC, this has already been done for you). 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. 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. If you don't have LaTeX, you can ftp the PostScript files from the ftp archives (see below). All documentation is also available on-line via the Python web site (http://www.python.org/, see below). It can also be downloaded separately from the ftp archives (see below) in Emacs INFO, HTML or PostScript form -- see the web site or 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, it is now maintained by Barry Warsaw . Web site -------- Python's own web site has URL http://www.python.org/. Come visit us! There are a number of mirrors, listed on the home page -- try a mirror that's close you you. Ftp site -------- Python's own ftp site is ftp.python.org, 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. The newsgroup, comp.lang.python, contains exactly the same messages as the mailing list (though not always in the same order, due to the mysterious nature of the Usenet news distribution algorithm). To subscribe to the mailing list, send mail containing your real name and e-mail address to "python-list-request@cwi.nl". Use the same address if you want to unsibscribed. (A real person reads these messages, so no LISTPROC or Majordomo commands, please, and please be patient -- normal turn-around time is about one working day.) The Python web site contains a search form that lets you search the newsgroup archives (or the web site itself). Click on the "search" link in the banner menu on any page of http://www.python.org/. Bug reports ----------- Bugs are best reported to the comp.lang.python newsgroup or the Python mailing list -- see the section "Newsgroup and mailing list" above. Before posting, check the newsgroup archives (see above) to see if your bug has already been reported! Questions --------- For help, if you can't find it in the manuals, the FAQ or on the web site, it's best to post to the comp.lang.python or the Python mailing list (see above). If you specifically don't want to involve the newsgroup or mailing list, send questions to python-help@python.org. 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 works with Tcl 7.5 and Tk 4.1 as well as with Tcl 7.4 and Tk 4.0. I didn't have the time to test it with Tcl 7.6 and Tk 4.2 yet, but it might well work. See http://www.sunlabs.com/research/tcl/ for more info on where to get Tcl/Tk. Also http://sunscript.sun.com/. 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". Uncomment one (normally the first) of the lines beginning with "#_tkinter" and un-comment the line beginning with "#TKPATH". If you have installed Tcl/Tk or X11 in unusual places, you will have to edit the first line to fix or add -I and -L options. See the Build Instructions above for more details. There is little documentation on how to use Tkinter; however most of the Tk manual pages apply quite straightforwardly. Begin with fetching the "Tk Lifesaver" document, e.g. ftp://ftp.python.org/pub/python/doc/tkinter-doc.tar.gz (a gzipped tar file containing a PostScript file) or the on-line version http://www.python.org/doc/life-preserver/index.html. Reading the Tkinter.py source will reveal most details on how Tkinter calls are translated into Tcl code. There are demos in the Demo/tkinter directory, in the subdirectories guido, matt and www (the matt and guido subdirectories have been overhauled to use more recent Tkinter coding conventions). 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 and leading underscore) which lives in Modules/_tkinter.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. BUGS A list of known bugs (not completely up-to-date) Demo/ Demonstration scripts, modules and programs Doc/ Documentation (LaTeX sources) 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 PC/ PC porting files (DOS, Windows, NT, OS/2) Parser/ The parser and tokenizer and their input handling Python/ The "compiler" and interpreter README The file you're reading now TODO A list of things that could be done (not up-to-date) 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) install-sh Shell script used to install files 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 CNRI 1895 Preston White Drive Reston, VA 20191 USA E-mail: guido@cnri.reston.va.us or guido@python.org 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 or Corporation for National Research Initiatives or CNRI not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. While CWI is the initial source for this software, a modified version is made available by the Corporation for National Research Initiatives (CNRI) at the Internet address ftp://ftp.python.org. STICHTING MATHEMATISCH CENTRUM AND CNRI DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM OR CNRI 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 (home page: http://www.python.org/~guido/)