protocol DiagonalMoves {
    func getDiagonalMoves(from pos: Square.Position) -> [Square.Position]
}

extension DiagonalMoves {
    func getDiagonalMoves(from pos: Square.Position) -> [Square.Position] {
        var squares = [Square.Position]()
        for i: (Int8, Int8) in [(1, -1), (1, 1), (-1, 1), (-1, -1)] {
            var currentSquare = pos + i
            while currentSquare.index != nil {
                squares.append(currentSquare)
                currentSquare += i 
            }
        }
        return squares
    }
}

protocol LinearMoves {
    func getLinearMoves(from pos: Square.Position) -> [Square.Position]
}

extension LinearMoves {
    func getLinearMoves(from pos: Square.Position) -> [Square.Position] {
        var squares = [Square.Position]()
        for i: (Int8, Int8) in [(1, 0), (0, 1), (-1, 0), (0, -1)] {
            var currentSquare = pos + i
            while currentSquare.index != nil {
                squares.append(currentSquare)
                currentSquare += i 
            }
        }
        return squares
    }
}