Re: [newbie] simple(?) data structures

[Jacob Sparre Andersen <sparre@nbi.dk>]

Roland Illig wrote:

>     type Stone is (Empty, Black, White);
>     type Player is (Black, White);

You might want to make Player a subtype of Stone:

      subtype Player is Stone range Black .. White;

That would remove the need for this declaration:

>     To_Stone : constant array (Player) of Stone := (Black => Black,
>     White => White);

And since the colours assigned to the players are derived from the
colours of the stones, it also makes sense from a logical point of
view.

>     type Move is private;

I would probably declare Move like this:

      type Move (Pass : Boolean := True) is
         record
            case Pass is
               when True =>
                  null;
               when False =>
                  X, Y : Positive;
            end case;
         end record;

With this construction, Move.X and Move.Y are only available if
Move.Pass is False.

And if you had used a generic package, parametrized with the size of
the board, I would definitely use the Board indexing type for Move.X
and Move.Y.

Jacob
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