Nikolay Metchev wrote:
data Face = Ace | Two | Three | Four | Five | Six | Seven | Eight | Nine | Ten | Jack | Queen | King deriving (Enum, Show, Eq)
listComparator :: (Eq a) => [a] -> a -> a -> Ordering listComparator xs a b = compare x y where x = elemIndex a xs y = elemIndex b xs
fourOfAKindBonusFaceOrder :: [Face] fourOfAKindBonusFaceOrder = [Queen, King, Ten, Ace, Nine, Jack]
Add: newtype FourOfAKindBonusFace = FKBF Face deriving Eq instance Ord FourOfAKindBonusFace where compare (FKBF x) (FKBF y) = listComparator fourOfAKindBonusFaceOrder x y Henceforth you can do these in the four-of-a-kind order: FKBF Queen >= FKBF Ten FKBF Ten <= FKBF Queen compare (FKBF Ten) (FKBF Queen)