John E. Davis' S-Lang library / interpreter
GPL-2.0 License
New features and upgrade information for version 2 are described in the appendices of doc/text/slang.txt and doc/text/cslang.txt. If you upgrading from version 1, then you should read these appendices.
One final note: The license for the library has changed to the GNU Public License. The Perl Artistic License is no longer supported.