CSNOBOL4 is a free port of the original SIL (SNOBOL4 Implementation
Language) "macro" version of SNOBOL4 (developed at Bell Labs) with the
C language as a target.

SNOBOL4, while known primarily as a string language excels at any task
involving symbolic manipulations. It provides dynamic typing, garbage
collection, user data types, and on the fly compilation.

CSNOBOL4 supports the full SNOBOL4 language plus BLOCKS and SPITBOL and
other extensions.