A Haskell chess library and console UCI frontend program

chessIO is a Haskell library for working with chess positions and moves, and a console frontend program (cboard) to work with UCI compatible chess engines.

The Library

The main module provided by the library is Game.Chess, which defines data types and functions for working with chess positions and moves. It offers a fully compliant move generator and parsing for and printing positions in Forsyth-Edwards Notation and moves in Algebraic Notation.

Module Game.Chess.UCI provides functionality to run an external process which understands the Universal Chess Interface protocol from within Haskell.

Console frontend for the Universal Chess Interface protocl

cboard is a simple console (text-mode) frontend for interacting with chess engines (like stockfish or glaurung) which make use of the UCI protocol.

To launch a chess engine, simply pass its executable name and arguments to cboard. For instance, cboard stockfish.

Opening book explorer

cbookview is a terminal application to explore commonly played openings. Passing a polyglot opening book file (with extension .bin) on the command line will allow you to explore the plies contained in that book file interactively. You can also open a PGN file (extension .pgn) which will be presented like it was an opening book. In other words, all the moves played in that PGN file will be merged into a single forest of plies. When exporing PGN files, no particular order of plies is imposed. When exploring a polyglot file the most popular moves will always come first.

For example, lets assume you want to examine blacks replies to the Ruy lopez. Use the cursor keys to navigate to the move after bishop b5. Here is what the interface will show:

a6         ┌─────────────────┐
Nf6       1│ R +   K Q B N R │        1.e4 e5 2.Nf3 Nc6 3.Bb5 a6
g6        2│ P P P   P P P P │
f5        3│   + N +   +   + │
Nge7      4│ +   + P +   +   │
Bc5       5│   +   p   + B + │
d6        6│ +   +   + n + p │
Nd4       7│ p p p + p p p + │
Bb4       8│ r n b k q b + r │
Bd6        └─────────────────┘
Qf6          h g f e d c b a
f6



Up/Down (kj) = change ply, Left/Right (hl) = back/forward                 ESC = Quit

Moving the cursor down the list of book moves will also update the position and game history. As already mentioned, the moves in polyglot book files are ordered according to popularity. So pawn to a6 is actually the most popular line of the Ruy Lopez.

The easteregg: Poor mans chessboard

If you press a (for "All moves") cbookview will switch to the tree of all possible moves. This is a poor mans way for following games and abusing cbookview as a two-player board.