"Read an expression, transform it, and print the result."

( 1 oop

(print prompt

(print (funcall transformer (read)))))

This function could then be used in writing each new interpreter:

(defun lisp 0

(interactive-interpreter '> #'eval))

(defun eliza 0

(interactive-interpreter 'eliza>

#'(lambda (x) (flatten (use-eliza-rules x)))))

Or, with the help of the higher-order function compose:

(defun compose (f g)

"Return the function that computes (f (g XI)."

#'(lambda (x) (funcall f (funcall g x))))

(defun eliza 0

(interactive-interpreter 'eliza>

(compose #'flatten #'use-eliza-rules)))