Re: [newbie] simple(?) data structures

["Nick Roberts" <nick.roberts@acm.org>]

"Matthew Heaney" <mheaney@on2.com> wrote in message
news:1ec946d1.0406231609.11a051cb@posting.google.com...

> package Go_Boards is
>
>    type Board_Type (Size : Positive) is private;
>
>    type Stone_Type is (Empty, Black, White);
>
>    function Stone (Board : Board_Type) return Stone_Type;
>
>    --function Width (B : BT) return Positive;  --same as B.Size?
>
> private
>
>    type Data_Type is
>      array (Positive range <>, Positive range <>) of Stone_Type;
>
>    type Board_Type (Size : Positive) is record
>       Data : Data_Type (1 .. Size, 1 .. Size);
>    end record;
>
> end Go_Boards;

(I can't resist improving on this a tad ;-)

   package Nicks_Go is

      type Board_Size is range 7..19; -- or whatever
      type Coordinate is range 0..Board_Size'Last;

      type Go_Board (Size : Board_Size) is private;

      type Cell_Content is (Empty, Black, White);
      subtype Stone_Color is Cell_Content range Black..White;

      function Cell (
            Board : Go_Board;
            Row, Col: Coordinate) return Cell_Content;

      procedure Set_Cell (
            Board : in out Go_Board;
            Row, Col: in Coordinate;
            Cell: in Cell_Content);

   private

      type Matrix_Array is array (
            Coordinate range <>,
            Coordinate range <>) of Cell_Content;

      type Go_Board_Type (Size : Board_Size) is
         record
            Matrix: Matrix_Array(1..Size, 1..Size); -- row, col
            -- probably a lot of other stuff too
         end record;

   end Nicks_Go;

   package body Nicks_Go is

      function Cell (
            Board : Go_Board;
            Row, Col: Coordinate) return Cell_Content is
      begin
         return Board.Matrix(Row,Col);
      end;

      procedure Set_Cell (
            Board : in out Go_Board;
            Row, Col: in Coordinate;
            Cell: in Cell_Content) is
      begin
         Board.Matrix(Row,Col) := Cell;
      end;

   end Nicks_Go;

Just for fun!

-- 
Nick Roberts