Module: EnPassantPieceControl

Included in:
Pawn
Defined in:
lib/sapphire-chess/movement_rules/en_passant_piece_control.rb

Instance Method Summary collapse

Instance Method Details

#add_en_passant_movement!(moves) ⇒ Object 



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# File 'lib/sapphire-chess/movement_rules/en_passant_piece_control.rb', line 2

def add_en_passant_movement!(moves)
  adyacent_enemy_pawn = pawn_to_pass.first
  return if adyacent_enemy_pawn.nil?

  moves << en_passant_target_square(adyacent_enemy_pawn)
end

#en_passant_target_square(adyacent_enemy_pawn) ⇒ Object 



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# File 'lib/sapphire-chess/movement_rules/en_passant_piece_control.rb', line 31

def en_passant_target_square(adyacent_enemy_pawn)
  direction = color == :white ? -1 : 1

  [adyacent_enemy_pawn.first + direction, adyacent_enemy_pawn.last]
end

#pawn_just_moved_two?(square) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/sapphire-chess/movement_rules/en_passant_piece_control.rb', line 21

def pawn_just_moved_two?(square)
  if color == :white
    board.black_player.history.last ==
      [[square.first - 2, square.last], square]
  else
    board.white_player.history.last ==
      [[square.first + 2, square.last], square]
  end
end

#pawn_to_pass(current_square = location) ⇒ Object 



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# File 'lib/sapphire-chess/movement_rules/en_passant_piece_control.rb', line 9

def pawn_to_pass(current_square = location)
  # See Piece#safe_moves, Board#is_a_duplicate?
  return [] if board.a_duplicate?

  left_square = [current_square.first, current_square.last - 1]
  right_square = [current_square.first, current_square.last + 1]

  [left_square, right_square].select do |square|
    board[square].is_a?(Pawn) && pawn_just_moved_two?(square)
  end
end