Representing a hand of cards as an F# type.

gistfile1.txt

    /// A hand of exactly five cards.
    type Hand(cards : Card[]) =
        do
            if cards.Length <> 5 then
                raise (ArgumentException("Invalid number of cards"))
        /// The cards in the hand, sorted in descending order of rank.
        member h.Cards = cards |> Array.sortBy (fun card -> 0 - card.Rank.SortValue)
        static member FromString (s : string) =
            let cards = 
                s.Split([|' '|])
                |> Array.map (fun s' -> Card.FromString s')
            Hand cards