A PGN parser and FEN generator for ruby.
On the command line, it is easy to read in and play through chess games in portable game notation format.
> games = PGN.parse(File.read("./examples/immortal_game.pgn"))
> game = games.first
> game.play
Play through the game using a or left arrow to move backward, and d
or right arrow to move forward. q or ^C quits play mode.
♜ ♞ ♝ ♛ ♚ ♝ ♞ ♜
♟ ♟ ♟ ♟ ♟ ♟ ♟ ♟
＿ ＿ ＿ ＿ ＿ ＿ ＿ ＿
＿ ＿ ＿ ＿ ＿ ＿ ＿ ＿
＿ ＿ ＿ ＿ ＿ ＿ ＿ ＿
＿ ＿ ＿ ＿ ＿ ＿ ＿ ＿
♙ ♙ ♙ ♙ ♙ ♙ ♙ ♙
♖ ♘ ♗ ♕ ♔ ♗ ♘ ♖
♜ ♞ ♝ ♛ ♚ ♝ ♞ ♜
♟ ♟ ♟ ♟ ♟ ♟ ♟ ♟
＿ ＿ ＿ ＿ ＿ ＿ ＿ ＿
＿ ＿ ＿ ＿ ＿ ＿ ＿ ＿
＿ ＿ ＿ ＿ ＿ ＿ ＿ ＿
＿ ＿ ＿ ＿ ♙ ＿ ＿ ＿
＿ ＿ ＿ ＿ ＿ ＿ ＿ ＿
♙ ♙ ♙ ♙ ＿ ♙ ♙ ♙
♖ ♘ ♗ ♕ ♔ ♗ ♘ ♖
...
You can also access all of the information about a game.
> game.positions.last
=>
♜ ＿ ♝ ♚ ＿ ＿ ＿ ♜
♟ ＿ ＿ ♟ ♗ ♟ ♘ ♟
♞ ＿ ＿ ＿ ＿ ♞ ＿ ＿
＿ ♟ ＿ ♘ ♙ ＿ ＿ ♙
＿ ＿ ＿ ＿ ＿ ＿ ♙ ＿
＿ ＿ ＿ ♙ ＿ ＿ ＿ ＿
♙ ＿ ♙ ＿ ♔ ＿ ＿ ＿
♛ ＿ ＿ ＿ ＿ ＿ ♝ ＿
> game.positions.last.to_fen
=> r1bk3r/p2pBpNp/n4n2/1p1NP2P/6P1/3P4/P1P1K3/q5b1 b - - 1 22
> game.result
=> "1-0"
> game.tags["White"]
=> "Adolf Anderssen"
It is possible to create a game without parsing a pgn file.
moves = %w{e4 c5 c3 d5 exd5 Qxd5 d4 Nf6}
game = PGN::Game.new(moves)
Note that if you simply want an abstract syntax tree from the pgn file,
you can use PGN::Parser.parse.
Forsyth Edwards Notation is a compact way to represent all of the information about a given chess position. It is easy to convert between FEN strings and chess positions.
> fen = PGN::FEN.start
=> rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
> fen = PGN::FEN.new("r1bk3r/p2pBpNp/n4n2/1p1NP2P/6P1/3P4/P1P1K3/q5b1 b - - 1 22")
> position = fen.to_position
=>
♜ ＿ ♝ ♚ ＿ ＿ ＿ ♜
♟ ＿ ＿ ♟ ♗ ♟ ♘ ♟
♞ ＿ ＿ ＿ ＿ ♞ ＿ ＿
＿ ♟ ＿ ♘ ♙ ＿ ＿ ♙
＿ ＿ ＿ ＿ ＿ ＿ ♙ ＿
＿ ＿ ＿ ♙ ＿ ＿ ＿ ＿
♙ ＿ ♙ ＿ ♔ ＿ ＿ ＿
♛ ＿ ＿ ＿ ＿ ＿ ♝ ＿
> position.to_fen
=> r1bk3r/p2pBpNp/n4n2/1p1NP2P/6P1/3P4/P1P1K3/q5b1 b - - 1 22
Add this line to your application's Gemfile:
gem 'pgn'
And then execute:
$ bundle
Or install it yourself as:
$ gem install pgn
- Fork it
- Create your feature branch (
git checkout -b my-new-feature) - Commit your changes (
git commit -am 'Add some feature') - Push to the branch (
git push origin my-new-feature) - Create new Pull Request