[Cyan]<CedarChest6.1>ChessHack>ChessDefs.mesa!1

ChessDefs.mesa

Russ Atkinson (RRA) November 8, 1985 2:32:46 pm PST

ChessDefs: CEDAR DEFINITIONS = {

Piece: TYPE = {

p0, p1, p2, p3, p4, p5, p6, p7,

br, wn, bb, q, k, wb, bn, wr

};

Pawn: TYPE = Piece[p0..p7];

NonPawn: TYPE = Piece[br..wr];

PieceColor: TYPE = {white, black, none};

WhiteBlack: TYPE = PieceColor[white..black];

ColoredPiece: TYPE = RECORD [color: PieceColor, piece: Piece];

noPiece: ColoredPiece = [none, p0];

Board: TYPE = ARRAY BoardIndex OF ColoredPiece;

If the board configuration or initial setup needs changing, please inform the International Chess Federation, who will be happy to oblige, I'm sure.

initialBoard: Board = [

[white, br], [white, wn], [white, bb], [white, q],
[white, k], [white, wb], [white, bn], [white, wr],

[white, p0], [white, p1], [white, p2], [white, p3],
[white, p4], [white, p5], [white, p6], [white, p7],

noPiece, noPiece, noPiece, noPiece, noPiece, noPiece, noPiece, noPiece,

[black, p0], [black, p1], [black, p2], [black, p3],
[black, p4], [black, p5], [black, p6], [black, p7],

[black, wr], [black, bn], [black, wb], [black, q],
[black, k], [black, bb], [black, wn], [black, br]

];

BoardIndex: TYPE = [0..64);

Position: TYPE = RECORD [

SELECT OVERLAID * FROM

rowCol => [row: [0..8), col: [0..8)],

index => [index: BoardIndex],

ENDCASE

];

Side: TYPE = {queen, king};

MoveList: TYPE = LIST OF Move;

Move: TYPE = RECORD [

piece: ColoredPiece,

Denotes piece being moved (the king for castling)

from: Position,

Denotes source square of this move

to: Position,

Denotes destination square of this move

alias: Piece ← p0,

Denotes alias (pawns only) added in this move

note: SpecialEffects ← [none[]],

Special effects (like capture & castle)

wasCheck: ARRAY WhiteBlack OF BOOL ← [FALSE, FALSE],

Used to save value of inCheck before the move

material: INTEGER ← 0

Used to save value of material before the move

];

SpecialEffects: TYPE = RECORD [

SELECT kind: * FROM

none => NULL,

castle => [side: Side],

remove => [victim: ColoredPiece, from: Position]

ENDCASE

];

GameState: TYPE = REF GameStateRep;

GameStateRep: TYPE = RECORD [

toMove: WhiteBlack ← white,

history: MoveHistory ← NIL,

future: MoveList ← NIL,

board: Board ← initialBoard,

material: ARRAY WhiteBlack OF INTEGER ← [0, 0],

Keeps track of the material weights for each side

coverage: ARRAY WhiteBlack OF Coverage ← [NIL, NIL],

Keeps track of the squares covered by white/black

inCheck: ARRAY WhiteBlack OF BOOL ← [FALSE, FALSE],

Keeps track of moves by king/rook

positions: ARRAY WhiteBlack OF Positions ← [NIL, NIL],

aliases: ARRAY WhiteBlack OF Aliases ← [NIL, NIL]

];

MoveHistory: TYPE = REF MoveHistoryRep;

MoveHistoryRep: TYPE = RECORD [

current: NAT,

last: NAT,

elems: SEQUENCE max: NAT OF Move];

Aliases: TYPE = REF AliasesRep;

AliasesRep: TYPE = ARRAY Pawn OF Piece;

When a pawn has turned into another piece it has an alias. Normally it has itself as an alias.

Positions: TYPE = REF PositionsRep;

PositionsRep: TYPE = ARRAY Piece OF FullPosition;

When a pawn has turned into another piece it has an alias. Normally it has itself as an alias.

FullPosition: TYPE = RECORD [onOff: {on, off}, position: Position];

Coverage: TYPE = REF CoverageRep;

CoverageRep: TYPE = ARRAY BoardIndex OF SquareCoverage;

Coverage describes which squares on the board are covered by various pieces.

SquareCoverage: TYPE = PACKED ARRAY Piece OF BOOL;

LookaheadStack: TYPE = REF LookaheadStackRep;

LookaheadStackRep: TYPE = RECORD [

levels: SEQUENCE max: NAT OF GameState

];

}.