[cl] Опции директив к format через аргументы функции.

(defun end-section-sign (string stream &optional (len 70))
  "Печатает знак конца секции."
  (format stream 
	  (concatenate 'string "~A~%#~" 
		       (write-to-string (- len 2))
		       ":@<End of ~A~>#~%~2:*~A~2%")
	  (make-array len 
		      :element-type 'character
		      :initial-element #\#)
	  string))