ChessFriend
===========

A chess engine written in Rust.

The project is divided into crates for major components of the engine. These
crates are collected in a Cargo workspace. All crates have the `chessfriend_`
naming prefix. The directory structure omits this prefix, and I also frequently
do when referring to them.



## Engine Crates

The engine is divided into several crates, each providing vital types and
functionality.



### `core`

A collection of types for representing core concepts in a chess game and the
engine. Types like `Color` (player or piece color), `Shape` (the shape of a
piece: knight, etc), `Piece` (a piece of a particular color and shape), and
`Score` (for scoring a board position) live here.



### `bitboard`

Implements an efficient BitBoard type. Bitboards use a 64-bit bit field to mark a
square on a board as occupied or free.



### `board`

Implements a `Board` type that represents a moment-in-time board position. FEN
parsing and production lives here.



### `moves`

The `Move` type lives here, along with routines for encoding moves in efficient
forms, parsing moves from algebraic notation, and recording moves in a game
context. Additionally, the move generators for each shape of piece are here.



### `position`

Exports the `Position` type, representing a board position within the context of
a game. As such, it also provides a move list, and methods to make and unmake
moves.



## Support Crates

These crates are for debugging and testing.



### `explorer`

This crate implements a small command-line application for "exploring" board
positions. I meant for this program to be a debugging utility so that I could
examine bitboards and other board structures live. It has grown over time to
also support more aspects of interacting with the engine. So you can also use it
to play a game!



### `perft`

A small Perft utility that executes perft to a given depth from some starting
position.





## Building

Build the engine in the usual Rusty way.

```sh
$ cargo build
```





## Testing

Test in the usual Rusty way.

```sh
$ cargo test
```

The engine has a fairly comprehensive unit test suite, as well as a decent pile
of integration tests.





## Authors

This engine is built entirely by me, Eryn Wells.