Elegant UCI chess engine.

Please see the README on GitHub at https://github.com/albertprz/turncoat#readme

turncoat

A minimalistic bitboard based UCI chess engine written in Haskell with a strong focus on a clear and modular implementation with adequate performance when compared with other open source engines.

It relies heavily on GHC as well as strictness annotations in order to optimize a high level program that leverages laziness in key areas (such as staged move generation and ordering) producing an efficient binary that can compete in a field where lower level languages (C, C++, Rust) are usually employed.

Turncoat has an official account on Lichess: https://lichess.org/@/TurncoatEngine

Characteristics

Move Generation

• Legal Move Generation
• Specialized Static Exchanges Move Generator
• Staged Move Generation (captures & promotions, quiet moves)

Search

• Negamax
• Alpha Beta Pruning
• Principal Variation Search
• Quiescence Search
• Iterative Deepening
• Transposition Table
• Null Move Pruning
• Futility Pruning
• Check Extensions
• Single move extensions
• Late Move Reductions

Move Ordering

• Staged Move Ordering
• Static Exchange Evaluation
• Killer Moves
• Static Evaluation Ordering (for quiet moves)

Evaluation

• Hand Tuned Evaluation
• Tapered Evaluation
• Material
• Piece Square Tables
• King Safety
• Mobility
• Passed Pawns
• Pawn King Shield
• Isolated & Doubled Pawns
• Knight Outposts
• Bishop Pair
• Rooks on Open Files
• Piece Threats.