Small implementation of Push 3 programming language in Common Lisp. Push 3 is described here http://tinyurl.com/push30.
Push is a programming language intended primarily for use in evolutionary computation systems (such as genetic programming systems), as the language in which evolving programs are expressed. Push has an unusually simple syntax, which facilitates the development (or evolution) of mutation and recombination operators that generate and manipulate programs. Despite this simple syntax, Push provides more expressive power than most other program representations that are used for program evolution.