guile

GNU Scheme interpreter (67K lines info).

guile [options] [script [args]]

-L <dir>    Add load path
-l <file>   Load source
-e <func>   Apply function
-c <expr>   Evaluate expression
-s <script> Execute script

REPL

(define (factorial n)
  (if (<= n 1) 1 (* n (factorial (- n 1)))))