datatype suit = Clubs | Hearts | Diamonds | Spades;

fun redSuit(Hearts) = true
  | redSuit(Diamonds) = true
  | redSuit(Clubs) = false
  | redSuit(Spades) = false;

datatype rank = Ace | Two | Three | Four | Five |Six | Seven |Eight | Nine | Ten | Jack | Queen | King;

datatype rank = Ace | Jack | Queen | King | Numbered of int;

datatype card = Card of rank * suit;

fun suitName Clubs = "Clubs"
  | suitName Hearts = "Hearts"
  | suitName Diamonds = "Diamonds"
  | suitName Spades = "Spades";

fun rankName Ace = "Ace"
  | rankName King = "King"
  | rankName Jack = "Jack"
  | rankName Queen = "Queen"
  | rankName (Numbered n) = Int.toString(n);

fun cardName (Card (rank, suit)) = (rankName rank) ^ " of " ^ (suitName suit);

fun red (Card (_, suit)) = redSuit suit;