From the distribution README:

This 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 run time typing,
garbage collection, user data types, on the fly compilation.  It's
primary weakness is it's simple syntax, and lack of "structured
programming" constructs.  However some consider the spareness of
SNOBOL4 syntax a strength when compared to some recent agglomerations
such as perl.
