Class: PGN::Move

Inherits:
Object
  • Object
show all
Defined in:
lib/pgn/move.rb

Overview

Move knows how to parse a move string in standard algebraic notation to extract all relevant information.

See Also:

Constant Summary collapse

SAN_REGEX =

A regular expression for matching moves in standard algebraic notation

/
  (?<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

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(move, player) ⇒ Move

Returns a new instance of Move.

Examples:

PGN::Move.new("e4", :white)

Parameters:

  • move (String) —

    the move in SAN

  • player (Symbol) —

    the player making the move



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# File 'lib/pgn/move.rb', line 95

def initialize(move, player)
  self.player = player
  self.san    = move

  match = move.match(SAN_REGEX)
  return  if match.nil?

  self.piece          = match[:piece]
  self.destination    = match[:destination]
  self.promotion      = match[:promotion]
  self.check          = match[:check]
  self.capture        = match[:capture]
  self.disambiguation = match[:disambiguation]
  self.castle         = match[:castle]
end

Instance Attribute Details

#capture ⇒ Object

piece/promotion/capture/disambiguation/castle have custom writers below (color normalization, nil-coalescing, etc.), so expose only readers here to avoid redefining attr_accessor setters (Lint/DuplicateMethods).



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# File 'lib/pgn/move.rb', line 59

class Move
  attr_accessor :san, :player, :destination, :check
  # piece/promotion/capture/disambiguation/castle have custom writers below
  # (color normalization, nil-coalescing, etc.), so expose only readers here
  # to avoid redefining attr_accessor setters (Lint/DuplicateMethods).
  attr_reader :piece, :promotion, :capture, :disambiguation, :castle

  # A regular expression for matching moves in standard algebraic
  # notation
  #
  SAN_REGEX = /
    (?<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)
    return  if match.nil?

    self.piece          = match[:piece]
    self.destination    = match[:destination]
    self.promotion      = match[:promotion]
    self.check          = match[:check]
    self.capture        = match[:capture]
    self.disambiguation = match[:disambiguation]
    self.castle         = match[:castle]
  end

  def piece=(val)
    # Castling SAN (O-O / O-O-O) has no piece attribute; the castle attribute
    # is set later in #initialize. Use a non-allocating prefix check instead
    # of `san.match('O-O')`, which allocated a MatchData on every Move.new.
    return if san.start_with?('O')

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

  def promotion=(val)
    return unless val

    val.downcase! if black?
    @promotion = val.delete('=')
  end

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

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

  def castle=(val)
    return unless val

    @castle = 'K' if val == 'O-O'
    @castle = 'Q' if val == 'O-O-O'
    @castle.downcase! if black?
  end

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

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

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

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

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

#castle ⇒ Object

piece/promotion/capture/disambiguation/castle have custom writers below (color normalization, nil-coalescing, etc.), so expose only readers here to avoid redefining attr_accessor setters (Lint/DuplicateMethods).



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# File 'lib/pgn/move.rb', line 59

class Move
  attr_accessor :san, :player, :destination, :check
  # piece/promotion/capture/disambiguation/castle have custom writers below
  # (color normalization, nil-coalescing, etc.), so expose only readers here
  # to avoid redefining attr_accessor setters (Lint/DuplicateMethods).
  attr_reader :piece, :promotion, :capture, :disambiguation, :castle

  # A regular expression for matching moves in standard algebraic
  # notation
  #
  SAN_REGEX = /
    (?<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)
    return  if match.nil?

    self.piece          = match[:piece]
    self.destination    = match[:destination]
    self.promotion      = match[:promotion]
    self.check          = match[:check]
    self.capture        = match[:capture]
    self.disambiguation = match[:disambiguation]
    self.castle         = match[:castle]
  end

  def piece=(val)
    # Castling SAN (O-O / O-O-O) has no piece attribute; the castle attribute
    # is set later in #initialize. Use a non-allocating prefix check instead
    # of `san.match('O-O')`, which allocated a MatchData on every Move.new.
    return if san.start_with?('O')

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

  def promotion=(val)
    return unless val

    val.downcase! if black?
    @promotion = val.delete('=')
  end

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

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

  def castle=(val)
    return unless val

    @castle = 'K' if val == 'O-O'
    @castle = 'Q' if val == 'O-O-O'
    @castle.downcase! if black?
  end

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

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

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

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

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

#check ⇒ String?

Returns whether the move results in check or mate.

Examples:

move1.check #=> "+"
move2.check #=> "#"

Returns:

  • (String, nil) —

    whether the move results in check or mate



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# File 'lib/pgn/move.rb', line 59

class Move
  attr_accessor :san, :player, :destination, :check
  # piece/promotion/capture/disambiguation/castle have custom writers below
  # (color normalization, nil-coalescing, etc.), so expose only readers here
  # to avoid redefining attr_accessor setters (Lint/DuplicateMethods).
  attr_reader :piece, :promotion, :capture, :disambiguation, :castle

  # A regular expression for matching moves in standard algebraic
  # notation
  #
  SAN_REGEX = /
    (?<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)
    return  if match.nil?

    self.piece          = match[:piece]
    self.destination    = match[:destination]
    self.promotion      = match[:promotion]
    self.check          = match[:check]
    self.capture        = match[:capture]
    self.disambiguation = match[:disambiguation]
    self.castle         = match[:castle]
  end

  def piece=(val)
    # Castling SAN (O-O / O-O-O) has no piece attribute; the castle attribute
    # is set later in #initialize. Use a non-allocating prefix check instead
    # of `san.match('O-O')`, which allocated a MatchData on every Move.new.
    return if san.start_with?('O')

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

  def promotion=(val)
    return unless val

    val.downcase! if black?
    @promotion = val.delete('=')
  end

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

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

  def castle=(val)
    return unless val

    @castle = 'K' if val == 'O-O'
    @castle = 'Q' if val == 'O-O-O'
    @castle.downcase! if black?
  end

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

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

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

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

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

#destination ⇒ String?

Returns the destination square of the piece.

Examples:

move.destination #=> "e4"

Returns:

  • (String, nil) —

    the destination square of the piece



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# File 'lib/pgn/move.rb', line 59

class Move
  attr_accessor :san, :player, :destination, :check
  # piece/promotion/capture/disambiguation/castle have custom writers below
  # (color normalization, nil-coalescing, etc.), so expose only readers here
  # to avoid redefining attr_accessor setters (Lint/DuplicateMethods).
  attr_reader :piece, :promotion, :capture, :disambiguation, :castle

  # A regular expression for matching moves in standard algebraic
  # notation
  #
  SAN_REGEX = /
    (?<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)
    return  if match.nil?

    self.piece          = match[:piece]
    self.destination    = match[:destination]
    self.promotion      = match[:promotion]
    self.check          = match[:check]
    self.capture        = match[:capture]
    self.disambiguation = match[:disambiguation]
    self.castle         = match[:castle]
  end

  def piece=(val)
    # Castling SAN (O-O / O-O-O) has no piece attribute; the castle attribute
    # is set later in #initialize. Use a non-allocating prefix check instead
    # of `san.match('O-O')`, which allocated a MatchData on every Move.new.
    return if san.start_with?('O')

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

  def promotion=(val)
    return unless val

    val.downcase! if black?
    @promotion = val.delete('=')
  end

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

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

  def castle=(val)
    return unless val

    @castle = 'K' if val == 'O-O'
    @castle = 'Q' if val == 'O-O-O'
    @castle.downcase! if black?
  end

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

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

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

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

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

#disambiguation ⇒ Object

piece/promotion/capture/disambiguation/castle have custom writers below (color normalization, nil-coalescing, etc.), so expose only readers here to avoid redefining attr_accessor setters (Lint/DuplicateMethods).



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# File 'lib/pgn/move.rb', line 59

class Move
  attr_accessor :san, :player, :destination, :check
  # piece/promotion/capture/disambiguation/castle have custom writers below
  # (color normalization, nil-coalescing, etc.), so expose only readers here
  # to avoid redefining attr_accessor setters (Lint/DuplicateMethods).
  attr_reader :piece, :promotion, :capture, :disambiguation, :castle

  # A regular expression for matching moves in standard algebraic
  # notation
  #
  SAN_REGEX = /
    (?<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)
    return  if match.nil?

    self.piece          = match[:piece]
    self.destination    = match[:destination]
    self.promotion      = match[:promotion]
    self.check          = match[:check]
    self.capture        = match[:capture]
    self.disambiguation = match[:disambiguation]
    self.castle         = match[:castle]
  end

  def piece=(val)
    # Castling SAN (O-O / O-O-O) has no piece attribute; the castle attribute
    # is set later in #initialize. Use a non-allocating prefix check instead
    # of `san.match('O-O')`, which allocated a MatchData on every Move.new.
    return if san.start_with?('O')

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

  def promotion=(val)
    return unless val

    val.downcase! if black?
    @promotion = val.delete('=')
  end

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

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

  def castle=(val)
    return unless val

    @castle = 'K' if val == 'O-O'
    @castle = 'Q' if val == 'O-O-O'
    @castle.downcase! if black?
  end

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

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

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

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

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

#piece ⇒ Object

piece/promotion/capture/disambiguation/castle have custom writers below (color normalization, nil-coalescing, etc.), so expose only readers here to avoid redefining attr_accessor setters (Lint/DuplicateMethods).



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# File 'lib/pgn/move.rb', line 59

class Move
  attr_accessor :san, :player, :destination, :check
  # piece/promotion/capture/disambiguation/castle have custom writers below
  # (color normalization, nil-coalescing, etc.), so expose only readers here
  # to avoid redefining attr_accessor setters (Lint/DuplicateMethods).
  attr_reader :piece, :promotion, :capture, :disambiguation, :castle

  # A regular expression for matching moves in standard algebraic
  # notation
  #
  SAN_REGEX = /
    (?<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)
    return  if match.nil?

    self.piece          = match[:piece]
    self.destination    = match[:destination]
    self.promotion      = match[:promotion]
    self.check          = match[:check]
    self.capture        = match[:capture]
    self.disambiguation = match[:disambiguation]
    self.castle         = match[:castle]
  end

  def piece=(val)
    # Castling SAN (O-O / O-O-O) has no piece attribute; the castle attribute
    # is set later in #initialize. Use a non-allocating prefix check instead
    # of `san.match('O-O')`, which allocated a MatchData on every Move.new.
    return if san.start_with?('O')

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

  def promotion=(val)
    return unless val

    val.downcase! if black?
    @promotion = val.delete('=')
  end

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

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

  def castle=(val)
    return unless val

    @castle = 'K' if val == 'O-O'
    @castle = 'Q' if val == 'O-O-O'
    @castle.downcase! if black?
  end

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

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

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

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

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

#player ⇒ Symbol

Returns the current player.

Examples:

move.player #=> :white

Returns:

  • (Symbol) —

    the current player



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# File 'lib/pgn/move.rb', line 59

class Move
  attr_accessor :san, :player, :destination, :check
  # piece/promotion/capture/disambiguation/castle have custom writers below
  # (color normalization, nil-coalescing, etc.), so expose only readers here
  # to avoid redefining attr_accessor setters (Lint/DuplicateMethods).
  attr_reader :piece, :promotion, :capture, :disambiguation, :castle

  # A regular expression for matching moves in standard algebraic
  # notation
  #
  SAN_REGEX = /
    (?<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)
    return  if match.nil?

    self.piece          = match[:piece]
    self.destination    = match[:destination]
    self.promotion      = match[:promotion]
    self.check          = match[:check]
    self.capture        = match[:capture]
    self.disambiguation = match[:disambiguation]
    self.castle         = match[:castle]
  end

  def piece=(val)
    # Castling SAN (O-O / O-O-O) has no piece attribute; the castle attribute
    # is set later in #initialize. Use a non-allocating prefix check instead
    # of `san.match('O-O')`, which allocated a MatchData on every Move.new.
    return if san.start_with?('O')

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

  def promotion=(val)
    return unless val

    val.downcase! if black?
    @promotion = val.delete('=')
  end

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

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

  def castle=(val)
    return unless val

    @castle = 'K' if val == 'O-O'
    @castle = 'Q' if val == 'O-O-O'
    @castle.downcase! if black?
  end

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

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

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

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

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

#promotion ⇒ Object

piece/promotion/capture/disambiguation/castle have custom writers below (color normalization, nil-coalescing, etc.), so expose only readers here to avoid redefining attr_accessor setters (Lint/DuplicateMethods).



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# File 'lib/pgn/move.rb', line 59

class Move
  attr_accessor :san, :player, :destination, :check
  # piece/promotion/capture/disambiguation/castle have custom writers below
  # (color normalization, nil-coalescing, etc.), so expose only readers here
  # to avoid redefining attr_accessor setters (Lint/DuplicateMethods).
  attr_reader :piece, :promotion, :capture, :disambiguation, :castle

  # A regular expression for matching moves in standard algebraic
  # notation
  #
  SAN_REGEX = /
    (?<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)
    return  if match.nil?

    self.piece          = match[:piece]
    self.destination    = match[:destination]
    self.promotion      = match[:promotion]
    self.check          = match[:check]
    self.capture        = match[:capture]
    self.disambiguation = match[:disambiguation]
    self.castle         = match[:castle]
  end

  def piece=(val)
    # Castling SAN (O-O / O-O-O) has no piece attribute; the castle attribute
    # is set later in #initialize. Use a non-allocating prefix check instead
    # of `san.match('O-O')`, which allocated a MatchData on every Move.new.
    return if san.start_with?('O')

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

  def promotion=(val)
    return unless val

    val.downcase! if black?
    @promotion = val.delete('=')
  end

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

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

  def castle=(val)
    return unless val

    @castle = 'K' if val == 'O-O'
    @castle = 'Q' if val == 'O-O-O'
    @castle.downcase! if black?
  end

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

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

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

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

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

#san ⇒ String

Returns the move string.

Examples:

move1.san #=> "O-O-O+"
move2.san #=> "Raxe1"
move3.san #=> "e8=Q#"

Returns:

  • (String) —

    the move string



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# File 'lib/pgn/move.rb', line 59

class Move
  attr_accessor :san, :player, :destination, :check
  # piece/promotion/capture/disambiguation/castle have custom writers below
  # (color normalization, nil-coalescing, etc.), so expose only readers here
  # to avoid redefining attr_accessor setters (Lint/DuplicateMethods).
  attr_reader :piece, :promotion, :capture, :disambiguation, :castle

  # A regular expression for matching moves in standard algebraic
  # notation
  #
  SAN_REGEX = /
    (?<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)
    return  if match.nil?

    self.piece          = match[:piece]
    self.destination    = match[:destination]
    self.promotion      = match[:promotion]
    self.check          = match[:check]
    self.capture        = match[:capture]
    self.disambiguation = match[:disambiguation]
    self.castle         = match[:castle]
  end

  def piece=(val)
    # Castling SAN (O-O / O-O-O) has no piece attribute; the castle attribute
    # is set later in #initialize. Use a non-allocating prefix check instead
    # of `san.match('O-O')`, which allocated a MatchData on every Move.new.
    return if san.start_with?('O')

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

  def promotion=(val)
    return unless val

    val.downcase! if black?
    @promotion = val.delete('=')
  end

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

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

  def castle=(val)
    return unless val

    @castle = 'K' if val == 'O-O'
    @castle = 'Q' if val == 'O-O-O'
    @castle.downcase! if black?
  end

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

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

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

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

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

Instance Method Details

#black? ⇒ Boolean

Returns whether it's black's turn.

Returns:

  • (Boolean) —

    whether it's black's turn



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# File 'lib/pgn/move.rb', line 164

def black?
  player == :black
end

#check? ⇒ Boolean

Returns whether the move results in check.

Returns:

  • (Boolean) —

    whether the move results in check



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# File 'lib/pgn/move.rb', line 146

def check?
  check == '+'
end

#checkmate? ⇒ Boolean

Returns whether the move results in checkmate.

Returns:

  • (Boolean) —

    whether the move results in checkmate



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# File 'lib/pgn/move.rb', line 152

def checkmate?
  check == '#'
end

#pawn? ⇒ Boolean

Returns whether the piece being moved is a pawn.

Returns:

  • (Boolean) —

    whether the piece being moved is a pawn



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# File 'lib/pgn/move.rb', line 170

def pawn?
  %w[P p].include?(piece)
end

#white? ⇒ Boolean

Returns whether it's white's turn.

Returns:

  • (Boolean) —

    whether it's white's turn



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# File 'lib/pgn/move.rb', line 158

def white?
  player == :white
end