#!/usr/local/bin/sbcl --script (defun remove-if-not-evenp (&optional) (remove-if-not #'evenp '(&optional))) (format t "~a"(remove-if-not #'evenp '(1 2 3 4 5 6 7 8 9 10))) (remove-if-not #'evenp '(1 2 3 4 5 6 7 8 9 10)) (remove-if-not-evenp(1 2 3 4))