This is flex, the fast lexical analyzer generator.
flex is a tool for generating scanners: programs which recognize
lexical patterns in text.
More information about flex as well as the latest official release of
flex can be found at:
Bug reports should be submitted using the SourceForge Bug Tracker for
The flex codebase is kept in git at:
There are several mailing lists available as well:
email@example.com - where posts will be made
announcing new releases of flex.
firstname.lastname@example.org - where you can post questions about
email@example.com - where you can discuss development of
Find information on subscribing to the mailing lists at:
The flex distribution contains the following files which may be of interest:
README - This file.
NEWS - current version number and list of user-visible changes.
INSTALL - basic installation information.
ABOUT-NLS - description of internationalization support in flex.
COPYING - flex's copyright and license.
doc/ - user documentation.
examples/ - containing examples of some possible flex scanners and a
few other things. See the file examples/README for more details.
TODO - outstanding bug reports, desired features, etc.
tests/ - regression tests. See TESTS/README for details.
po/ - internationalization support files.
You need the following tools to build flex from the maintainer's
compiler suite - flex is built with gcc
bash, or a good Bourne-style shell
m4 - m4 -p needs to work; GNU m4 and a few others are suitable
GNU bison; to generate parse.c from parse.y
autoconf 2.69; for handling the build system
automake 1.12.2; for Makefile generation
gettext 0.18; fori18n support
help2man 1.36; to generate the flex man page
tar, gzip, etc.; for packaging of the source distribution
GNU texinfo 498; to build and test the flex manual
GNU indent 2.8; for indenting the flex source the way we want it done
Once you have all the necessary tools installed, life becomes
simple. To prepare the flex tree for building, run the script:
in the top level of the flex source tree.
This script calls the various tools needed to get flex ready for the
GNU-style configure script to be able to work.
From this point on, building flex follows the usual configure, make,
make install routine.
This file is part of flex.
This code is derived from software contributed to Berkeley by
The United States Government has rights in this work pursuant
to contract no. DE-AC03-76SF00098 between the United States
Department of Energy and the University of California.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
Neither the name of the University nor the names of its contributors
may be used to endorse or promote products derived from this software
without specific prior written permission.
THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR