on SNOBOL4 patterns. Several implementations are currently available. Macro SNOBOL4 in C written by Phil Budne is a free, open source implementation, capable of running on almost any platform. Catspaw, Inc provided a commercial implementation of the SNOBOL4 language for many different computer platforms, including DOS, Macintosh, Sun, RS/6000, and others, and these implementations are now available free from Catspaw. Minnesota SNOBOL4, by Viktors Berstis, the closest PC implementation to the original IBM mainframe version (even including Fortran-like FORMAT statement support) is also free. Although SNOBOL itself has no structured programming features, a SNOBOL preprocessor called Snostorm was designed and implemented during the 1970s by Fred G. Swartz for use under the Michigan Terminal System (MTS) at the University of Michigan. Snostorm was used at the eight to fifteen sites that ran MTS. It was also available at University College London (UCL) between 1982 and 1984. Snocone by Andrew Koenig adds block-structured constructs to the SNOBOL4 language. Snocone is a self-contained programming language, rather than a proper superset of SNOBOL4. The SPITBOL implementation also introduced a number of features which, while not using traditional structured programming keywords, nevertheless can be used to provide many of the equivalent capabilities normally thought of as "structured programming", most notably nested if/then/else type constructs. These features have since been added to most recent SNOBOL4 implementations. After many years as a commercial product, in April 2009 SPITBOL was released as free software under the GNU General Public License. Naming According to Dave Farber, he, Griswold and Polonsky "finally arrived at the name Symbolic EXpression Interpreter SEXI." Common backronyms of "SNOBOL" are 'String Oriented Symbolic Language' or (as a quasi-initialism) 'StriNg Oriented symBOlic Language'. See also Icon (programming language) Snowball (programming language) Snostorm SPITBOL Unicon (programming language) References Further reading republished Salida, CO: Catspaw, 1986 (). External links CSNOBOL4 is a free and open source BSD-licensed port of the original Bell Labs SNOBOL4 to systems with a C compiler, and includes SPITBOL and Blocks enhancements. Catspaw, Inc. offers implementations of and commercial support for SNOBOL4 ]. For a small brief taste of what SNOBOL4 is about try this online compiler Try It Online (Snobol4/CSNOBOL) Online compiler Pattern matching programming languages Programming languages created in 1962 SNOBOL programming language family Assembly language software Text-oriented programming languages Programming languages Homoiconic programming languages 1962 software