'chem' is a 'roff' language to generate chemical structure diagrams.
'@g@chem' is a 'groff' preprocessor that produces output suitable for
the '@g@pic' preprocessor.

The original version of 'chem' is an 'awk' script written by Brian
Kernighan <http://cm.bell-labs.com/cm/cs/who/bwk/index.html>.  The
source files of the 'awk' version of 'chem' are available at
<http://cm.bell-labs.com/netlib/typesetting/chem.gz>.

This project is a rewrite of 'chem' in Perl for the GNU 'roff' project
'groff'.  It was written under Perl v5.8.8, but at least Perl v5.6 is
needed to run the Perl version of 'chem'.

In comparison to the original 'awk' version of 'chem', the Perl
version does the following changements:
- the options -h, --help, -v, --version to output usage and version
information are added.
- remove some functions 'inline', 'shiftfields', and 'set' and some
variables that are used only once.

The subdirectory 'examples/' contains example files for chem.  They
are written in the 'chem' language.  The file names end with .chem.


####### License

Copyright (C) 2006-2020 Free Software Foundation, Inc.
Written by Bernd Warken <groff-bernd.warken-72@web.de>.

This file is part of 'chem', which is part of 'groff'.

'groff' is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License (GPL) version 2 as
published by the Free Software Foundation.

'groff' is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

The GPL2 license text is available in the internet at
<http://www.gnu.org/licenses/gpl-2.0.html>.


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