Method: PGN::Move#capture

Defined in:
lib/pgn/move.rb,
lib/pgn/move.rb

#capture ⇒ String?

Returns whether the move is a capture.

Examples:

move.capture #=> "x"

Returns:

  • (String, nil) —

    whether the move is a capture



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# File 'lib/pgn/move.rb', line 58

class Move
  attr_accessor :san, :player
  attr_accessor :piece, :destination, :promotion, :check, :capture, :disambiguation, :castle

  # A regular expression for matching moves in standard algebraic
  # notation
  #
  SAN_REGEX = %r{
    (?<piece>          [BKNQR]      ){0}
    (?<destination>    [a-h][1-8]   ){0}
    (?<promotion>      =[BNQR]      ){0}
    (?<check>          [#+]         ){0}
    (?<capture>        x            ){0}
    (?<disambiguation> [a-h]?[1-8]? ){0}

    (?<castle>         O-O(-O)?     ){0}

    (?<normal>
      \g<piece>?
      \g<disambiguation>
      \g<capture>?
      \g<destination>
      \g<promotion>?
    ){0}

    \A (\g<castle> | \g<normal>) \g<check>? \z
  }x

  # @param move [String] the move in SAN
  # @param player [Symbol] the player making the move
  # @example
  #   PGN::Move.new("e4", :white)
  #
  def initialize(move, player)
    self.player = player
    self.san    = move

    match = move.match(SAN_REGEX)

    match.names.each do |name|
      if self.respond_to?(name)
        self.send("#{name}=", match[name])
      end
    end
  end

  def piece=(val)
    return if san.match("O-O")

    val ||= "P"
    @piece = self.black? ?
      val.downcase :
      val
  end

  def promotion=(val)
    if val
      val.downcase! if self.black?
      @promotion = val.delete("=")
    end
  end

  def capture=(val)
    @capture = !!val
  end

  def disambiguation=(val)
    @disambiguation = (val == "" ? nil : val)
  end

  def castle=(val)
    if val
      @castle = "K" if val == "O-O"
      @castle = "Q" if val == "O-O-O"
      @castle.downcase! if self.black?
    end
  end

  # @return [Boolean] whether the move results in check
  #
  def check?
    self.check == "+"
  end

  # @return [Boolean] whether the move results in checkmate
  #
  def checkmate?
    self.check == "#"
  end

  # @return [Boolean] whether it's white's turn
  #
  def white?
    self.player == :white
  end

  # @return [Boolean] whether it's black's turn
  #
  def black?
    self.player == :black
  end

  # @return [Boolean] whether the piece being moved is a pawn
  #
  def pawn?
    ['P', 'p'].include?(self.piece)
  end

end