SETL4 is a new implementation of Setl that brings the raw power and speed of SPITBOL to non-numeric computation using set-theoretic constructs
It was designed and created by Dave Shields, the author of the first implementation of Setl, written in 1970-1971, using as ASR 33 Teletype.
Setl4 is written in SPITBOL, a very efficient implementation of Snobol4.
Source and binaries can be found at http://github.com/setl4.
Setl4 is licensed under the MIT License, SPITBOL under GPLv2 (or later)