Re: Possible problem with gnuchess

[Simon Waters]

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Matthew wrote:
>
> I am running gnuchess version 5.05. I type the following
sequence of
> commands in order:
>
>   force
>   e4
>   switch
>   show moves
>   switch
>   show board
>
> The final output from "show board" is:
>
>   Black (1) : show board
>
>   black  KQkq  e3
>   r n b q k b n r
>   p p p p p p p p
>   . . . . . . . .
>   . . . . . . . .
>   . . . . P . . .
>   . . . . . . . .
>   P P P P p P P P
>   R N B Q K B N R
>
> A black pawn has appeared on e2.  Is this problem easy to fix?
 Any help
> would be appreciated.

This is a familiar issue - but I'm not sure I've found the right
fix yet.

The logic is presumably "UnMakeMove" expects a pawn to occur one
square short of the en-passant square, obviously if you switch
sides then the ep square is all wrong.

A workaround is in the CVS version of the "black" and "white"
commands (expected to be (re)introduced in 5.06 to support
icsdrone) just blanks the "ep" square when the side is changed.

The workaround is fine for "white" and "black" (and icsdrone)
but I'm not clear it is great if switch is invoked twice.

(Just add "board.ep = -1;" in switch)

Thanks for the report,

Life would be so much simpler if pawns only moved one square at
a time.

Can I ask how you stumbled on this command sequence, are you
designing a GUI or something? As I'm not clear why we have a
switch command (Do you know Stuart?)

 Simon
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