Re: Newbie question

[Adam Beneschan <adam@irvine.com>]

On Mar 12, 10:14 am, stefan-lu...@see-the.signature wrote:
> > > type Piece_T(Color: Color_T) is
> > >   record
> > >     case Color is
> > >       when White =>
> > >         White_Piece: Piece_Type_T;
> > >       when Black =>
> > >         Black_Piece: Piece_Type_T;
> > >       when None =>
> > >         null;
> > >     end case;
> > >   end record;
>
> > The problem with this is that you'd then need two code paths for
> > Black_Piece and White_Piece, every time.
>
> Right. Actually, I anticipated that you would *want* two code paths for
> the black and for the white pieces.

I don't see why... I'd anticipate writing a subprogram like

   function Compute_Best_Move_For (Color: Color_T) return Move_T;

[more accurately, instead of Color_T, we'd use a subtype that is a
subrange of Color_T that allows only Black and White].  Now having two
different paths would be an utter nuisance.  Aside from the small
detail that the pawns move in different directions, the algorithm
would be exactly the same for both colors.

In fact, I'd think most of the algorithms you would want to write that
pertain to one particular player would work exactly the same for Black
and White, except for pawn direction, and that can be dealt with by
setting up some variable with value +1 for White and -1 for Black (or
vice versa).

                                -- Adam