;; Unions and list of structs


 ;; TODO: create the following structures: 
 ;; --DVD has a director, title, length
 ;; --Book has a author, title, num-pages
 ;; --CD has an artist, title, num-tracks, length
 



 ;; TODO: create a template for Media that takes one of the structures we've defined

   



;; Create a function, get-author, that when given a form of media(cd,dvd,or book) returns the 
;; name(artist,director,or author) and title of the media as a string seperated by a space


;;examples: 
;;  (get-author (make-book "joe" "lucky" 100)) => "joe lucky"




;; Create a function, title-length, which when given a form of media, returns the title of the media
;; and the length( or num-pages) of the media as a string seperated by a space




;; list-of-media
;; --empty
;; --(cons media list-of-media)



;; Create a function, list-author, which takes a list of media as input and for each item in the list
;; returns just the artist/director/author and title as a string followed by a space




;;examples:
;; (list-author (list (make-cd "ath" "titl" 12 100) (make-dvd "dir" "titl" 122) (make-book "auth" "titl" 121)))
;;       => (list "ath title" "dir title" "auth titl")