A Ruby Gem to validate Chess moves and (eventually) produce algebraic and FEN notation
Chess is not yet on Rubygems, due to the early state of its development and the prescene of a blank gem with a conflicting name
The best way to install Chess is using Bundler. Add the following to your Gemfile
gem 'chess', :git => 'http://github.com/edpaget/chess-rules.git'
Chess is mainly intended to validate chess moves, so it should be used by creating a new Chess game (either blank or with moves given to), and then feeding moves that need to be validating into the game.
Create a new game as follows
Chess::Game.new() # Blank Game
Chess::Game.new( :game => [['e2e4', 'c7c5'], ['g1f3', nil]]) # Game with moves already made
The format for feeding moves into the game is group half-moves into an array of all the full-moves. If white made the last move, black's next half-move should be marked as nil.
You can then make moves by calling the #move method on a game
game = Chess::Game.new()
game.move 'e2e4'
If a move is not legal one of three errors will be raised
Chess::IllegalMove # if a move cannot be made by a piece or if it will put the mover's king in check
Chess::WrongColor # if a move will move a piece by the color that made the previous move
Chess::NoPieceOnSquare # if there isn't a piece on the square to be moved from
Chess only depends on rspec for running its test suite.
Chess is not currently compatible with Ruby 1.8.7, but has been tested on both 1.9.2 and 1.9.3
The main move forward with Chess will be to include support for output to various notation formats including algebriac notation and FEN notation.
I also plan to add support for detecting more endgame conditions such as the fifty move rule, perpetual check, and 3-move repetition draws.