(define comment (recursive-parser (sequence (char-seq "(")
			  (zero-or-more
			    (any-of
			      ctext
			      quoted-pair
			      comment))
			  (char-seq ")"))))


(define (delimited-by delimiter)
  (sequence* ((_ (zero-or-more
		   (any-of linear-white-space comment)))
	      (delimiter (char-seq delimiter))
	      (_ (zero-or-more
		   (any-of linear-white-space comment))))

	     (result delimiter)))