A number of Lisp instructions are implemented (see below). The choice of instructions and some of the implementations of the composite functions were taken from Roger Rohrbach's Lisp in Awk interpreter. The syntax is standard, and only integer arithmetic is available. Primarily because it is easy to implement, scoping is dynamic as in original Lisp and unlike modern Lisp or Scheme.
Since this is pretty much a toy, it doesn't do much in the way of error handling. However, it should work on correct Lisp code; if it breaks on code you believe to be correct, please send me mail.
To see the source code, just View-Source on this page; but see the copying restrictions below.