This is a simple library for checking which moves are allowed on a given chess position. As far as I know, all chess rules have been implemented and work correctly.

The API is quite simple. To create a chess board use the fromFEN function, which loads a board from a FEN string (see http://en.wikipedia.org/wiki/Forsyth%E2%80%93Edwards_Notation). You can then perform moves on the board by using the move function which takes a string of the form "b2b3" for regular moves, "0-0" for a kingside castle, "0-0-0" for a queenside castle, and "a7a8q" for promotion to a queen. The moveSAN function accepts moves in standard algebraic notation, like "Nc3", "e4" and "e8Q".

The PGN module can be used to parse PGN databases to a list of games. It will only parse the required tags, and will strip all comments, numeric annotations and recursive annotations.

The code is quite messy and lacks documentation, so please take a look at ChessTest.hs and PGNTest.hs to see how to use it.