cleanup stuff related to move legality checks and attack checks - Githubissues

Sopel97 / chess_pos_db

Database software for chess position statistics. Designed to provide high performance and handle billions of games.

MIT License

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cleanup stuff related to move legality checks and attack checks #17

Closed Sopel97 closed 4 years ago

Sopel97 commented 4 years ago

in chess_posdb we have to cleanup some stuff related to move/position legality checks.
- in particular Board::isKingAttackedAfterMove, Board::isSquareAttackedAfterMove need better implementations
- Board::isSquareAttacked shouldn't have the 'captured' and 'occupied' parameter
- remove this assert https://github.com/Sopel97/chess_pos_db/blob/master/src/chess/Position.cpp#L26
- overall all predicates that chess whether something is attacked now or after a move need to be rethought and reimplemented.
- what we need (all of these happen to not require pos state info so they may be implemented in board only):
  - pos/board.isSquareAttacked(Square, Color attacker)
  - pos/board.isSquareAttackedAfterMove(Square, Move, Color attacker)
  - pos/board.isPieceAttacked(Square) - similar to isSquareAttacked but attacker depends on the piece color. false if empty
  - pos/board.isPieceAttackedAfterMove(Square pieceSq, Move) - false if empty
  - pos/board.createsDiscoveredAttackOnOwnKing(Move) - attacker color opposite to color of the piece being moved
  - pos/board.createsAttackOnOwnKing(Move) - calls board.isPieceAttackedAfterMove(ksq, Move)
  - pos/board.attackers(Square)
  - pos/board.attacks(Square) - empty bitboard if square empty
- additionally we may want
  - pos.isMoveLegal(Move) - this would take ANY move, not just a pseudoLegalMove
  - pos.isPseudoLegalMoveLegal(Move) - like it is in movegen now
  - pos.isMovePseudoLegal(Move) - takes ANY move