2.27.tex

\documentclass[a4paper,12pt]{article}
\usepackage{listings}
\lstset{language=Lisp}

\begin{document}
\begin{lstlisting}
(define (deep-reverse l)
  (define (iter res l)
    (cond ((null? l) res)
          ((pair? (car l))
           (iter (cons (iter '() (car l))
                       res)
                 (cdr l)))
          (else (iter (cons (car l) res)
                      (cdr l)))))
  (iter '() l))
\end{lstlisting}
\end{document}