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Date: Thu, 12 Mar 2009 15:16:26 +0100
From: Olivier Scalbert <olivier.scalbert@algosyn.com>
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Subject: Re: Newbie question
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Date: 2009-03-12T15:16:26+01:00
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Ludovic Brenta wrote:

> Solution 1: a variant record:
> 
> type Square_T (Empty : Boolean) is record
>    case Empty is
>       when True => null;
>       when False => Piece : Piece_T;
>    end case;
> end record;
> 
> type Board_T is array (1 .. 8, 1 .. 8) of Square_T;
> 
> Solution 2: merge the Boolean directly into Piece_T:
> 
> type Piece_T (Present : Boolean) is record
>    case Present is
>       when True =>
>          Color : Color_T;
>          Piece_Type : Piece_Type_T;
>       when False =>
>          null;
>    end case;
> end record;
> 
> Solution 3: introduce a new value for Piece_Type_T:
> 
> type Piece_Type_T is (None, Pawn, Knight, Bishop, Rook, Queen, King);
> 
> I don't know which is the best solution; perhaps you'd like to try
> them all and see how well they integrate with the algorithms.  I think
> Solution 3 is the most error-prone, though.
> 
> --
> Ludovic Brenta;

3 solutions ! Thanks Ludovic.

I like the first two solutions. With solution 3, you can have an empty 
square (None) with a color.

Olivier