データ型カードを受け入れ、ブール値を返す関数でcase式を作成できますか？

Question

datatype cards = king of int * int 
       | queen of string 
       | jack of cards 
       | ace of cards * cards 
       | joker of int * cards 

Answer 1

です。

fun hasKing cards = 
    case cards of 
     king (i, j)   => true 
     | queen s    => false 
     | jack cards1   => hasKing cards1 
     | ace (cards1, cards2) => hasKing cards1 orelse hasKing cards2 
     | joker (i, cards2) => hasKing cards2 

しかし、私は、関数と区別するために大文字で私の値コンストラクタに名前を付けます：

datatype cards = King of int * int 
       | Queen of string 
       | Jack of cards 
       | Ace of cards * cards 
       | Joker of int * cards