fen

fen - Rewrite of FEN utility in haskell

Feed it PGN-notation chess moves and it produces the corresponding chess position, FEN-encoded. Also checks move legality.

intended usage:

> fen "e4 c5"
rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1
rnbqkbnr/pp1ppppp/8/2p5/4P3/5N2/PPPP1PPP/RNBQKB1R b KQkq - 1 2

Later on, we can add a fancy UI with e.g FRP javascript and websockets 'n stuff.

How to Run

Currently, nothing is working really, except the test suites. To generate them do

    scons

then

    cabal test

if you are lucky the scons-command should have generated a test-suites-directory for you, and cabal test ran the tests.

Architectural Overview

The logic is centered around the concept of 'promoting' moves.

You start with something like a PartialMove, where

'Partial' is intended to mean 'lacking information that uniquely identifies the move'.

You can then use the LegalMove-module to promote your moves, i.e, by supplying more information. The LegalMove-module can take any type of (partially specified) move and calculate all the legal moves that said move could represent.

Note that, currently castling moves cannot be processed (Work in Progress).

In the end, when the program is run it will be the responsibility of the user to always supply enough information to uniquely determine a move. If this requirement is not satisfied, there will be an error: "Ambiguous move. Candidates are: [List of candidates]"

Modules of importance:

• All Move-modules: Move, PartialMove, FullMove, LegalMove
• The *Updates (e.g PositionUpdates) represent how to update a Position, Board or Properties after performing a move
• To parse moves out of strings, see PgnParse.

TODOs

• Define data type that supports both normal moves and castling (e.g ExtendedMove)
• Write PGN move parsing functionality (test)
• Write main.hs (parse command line args, display errors in a user-friendly way etc)
• Support loading entire .pgn-files and parsing out all the moves and resulting positions
• Create deeper module hierarchies to better organize code

Long term TODOs

• Support move translation, e.g "e4 -> KP4" (would be cool!)
• Develop a GUI (elm, websockets??)
• Allow importing, searching etc to chess game database
• Support talking to chess engine