Module: King

Extended by:
King
Includes:
Moves
Included in:
BlackKing, King, WhiteKing
Defined in:
lib/king.rb

Instance Method Summary collapse

Methods included from Moves

#diagonal, #horizontal, #move, #vertical

Instance Method Details

#castle(board, x, y, x_diff) ⇒ Object 



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# File 'lib/king.rb', line 34

def castle(board,x,y,x_diff)
  direction = x_diff/x_diff.abs

  # get rook, raise illegal move unless start, else move the rook
  if direction > 0 # right
    rook = board.at(7,y)
    rook_x = x-1
  else             # left
    rook = board.at(0,y)
    rook_x = x+1
  end

  if rook.is_a?(Rook) && rook.friend_of?(self) && rook.start
    board.move(rook,rook_x,y)
  else
    raise Game::IllegalMove, "King cannot castle this way, now"
  end
end

#checked?(board, x = @x, y = @y, x_diff = 0) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/king.rb', line 53

def checked?(board,x = @x, y = @y, x_diff = 0)
  enemies = board.enemies(self)
  spaces = [[x,y]]

  if x_diff.abs > 1 #castling
    spaces << [x - 1*(x_diff/x_diff.abs), y]
  end

  enemies.each do |enemy|
    spaces.each do |space|
      begin
        enemy.illegal(board,*space)
        return true
      rescue Game::IllegalMove
        :not_checked
      end
    end
  end

  return false 
end

#illegal(board, x, y) ⇒ Object 



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# File 'lib/king.rb', line 6

def illegal(board,x,y)
  x_diff = x-@x
  possible_moves = []

  possible_moves += Board.board_safe(
      diagonal(1) + horizontal(1) + vertical(1) 
  )

  if @start #castling
    possible_moves += [
      [@x-(2 * @direction), @y], [@x+(2 * @direction), @y] 
    ]
  end

  if not(possible_moves.any? {|move| move == [x,y]})
    raise Game::IllegalMove, "#{x},#{y} is not a possible move" 
  elsif board.at(x,y).friend_of?(self)
    raise Game::IllegalMove, "#{x},#{y} is occupied by a friend"
  elsif jumped?(board,x,y)
    raise Game::IllegalMove, "Kings can't jump"
  elsif checked?(board,x,y,x_diff)
    raise Game::IllegalMove, "King can't move into check"
  else
    castle(board,x,y,x_diff) if (x_diff).abs > 1
    :legal_move
  end
end