(xdef 'close (lambda args
               (map (lambda (p)
                      (cond ((input-port? p)   (close-input-port p))
                            ((output-port? p)  (close-output-port p))
                            ((tcp-listener? p) (tcp-close p))
                            (#t (err "Can't close " p))))
                    args)
               'nil))

From ac.scm ©