using MLStyle

@data Shape begin # Define an algebraic data type Shape
    Rock
    Paper
    Scissors
end

# Determine who wins a game of rock paper scissors with pattern matching
play(a::Shape, b::Shape) = @match (a, b) begin
    (Paper,    Rock)      => "Paper Wins!";
    (Rock,     Scissors)  => "Rock Wins!";
    (Scissors, Paper)     => "Scissors Wins!";
    (a, b)                => a == b ? "Tie!" : play(b, a)
end