shithub: moonfish

Clone

Last commit

make position validation faster

About

<!-- moonfish's license: 0BSD -->
<!-- copyright 2025 zamfofex -->

moonfish
===

**moonfish** is a simple chess bot written in C89 (using just a few POSIX and C11 APIs).

- lightweight and fun!
- simple evaluation based on PSTs
- MCTS (Monte Carlo tree search)
- cute custom TUI for UCI bots
- custom Lichess integration
- custom IRC integration

contributing to moonfish
---

Contributions to moonfish are always welcome! Whether you have thoughts or ideas to share or complaints to make, any kind of help is very appreciated!

Please feel free to reach out!

- via email: <zamfofex@twdb.moe>
- via IRC: [#moonfish] on [Libera Chat]
- off‐topic channel: [#moonfish-miscellany]

[Libera Chat]: <https://libera.chat>
[#moonfish]: <https://web.libera.chat/#moonfish>
[#moonfish-miscellany]: <https://web.libera.chat/#moonfish-miscellany>

compiling from source
---

You’ll need a C compiler (like [GCC] or [Clang]) and also [POSIX Make] (like [GNU Make] or [BSD Make] or [PDP Make]).

~~~
make moonfish
~~~

[POSIX Make]: <https://pubs.opengroup.org/onlinepubs/9799919799/utilities/make.html>
[GNU Make]: <https://gnu.org/software/make/>
[BSD Make]: <https://man.netbsd.org/make.1>
[PDP Make]: <https://frippery.org/make/>
[GCC]: <https://gnu.org/software/gcc/>
[Clang]: <https://clang.llvm.org>

You may instead run your compiler manually if you prefer.

~~~
# (replace 'cc' with your compiler of choice)
cc -O3 -o moonfish chess.c search.c main.c -lm -pthread -latomic
~~~

compilation configuration
---

**Note:** Consult the makefile for more configuration options.

- **threads** — moonfish uses C11 `<threads.h>` by default
  - `make CPPFLAGS=-Dmoonfish_pthreads` to compile with pthreads instead
  - `make CPPFLAGS=-Dmoonfish_no_threads` to disable threads altogether
- **clock/time** — moonfish uses `clock_gettime(3)` by default
  - `make CPPFLAGS=-Dmoonfish_no_clock` to use `time(3)` instead
- **libraries** — moonfish uses `-pthread` and `-latomic` by default
  - `make LIBPTHREAD= LIBATOMIC=` to disable each flag (respectively)
  - `make LIBPTHREAD=-lpthread` to replace `-pthread` with `-lpthread`

notes for MacOS
---

MacOS usually lacks `-latomic` and C11 `<threads.h>`, so you may need to compile with `-Dmoonfish_pthreads` and `LIBATOMIC=`.

~~~
# (configuring the compilation for MacOS)
make CPPFLAGS=-Dmoonfish_pthreads LIBATOMIC= moonfish
~~~

using moonfish’s tools
---

moonfish also has a few tools to use UCI bots in various ways.

- `analyse` — TUI for analysing chess games with UCI bots
- `chat` — IRC integration for UCI bots
- `lichess` — Lichess integration for UCI bots

To compile them, simply run `make` followed by the name of the tool you want to compile.

~~~
make analyse
make chat
make lichess
~~~

Each of them has fairly good `--help` documentation, so you may use that to learn more about them!

~~~
./analyse --help
./chat --help
./lichess --help
~~~

Note that some of them have external dependencies!

- `chat` depends on [LibreSSL] (`-ltls`)
- `lichess` depends on [LibreSSL] (`-ltls`) and [cJSON] (`-lcjson`)

[LibreSSL]: <https://libressl.org>
[cJSON]: <https://github.com/DaveGamble/cJSON>

compiling on 9front
---

You’ll need [NPE]. After that, you should be able to just compile moonfish and some of its tools with `mk`. (They have no further dependencies on 9front.)

[NPE]: <https://git.sr.ht/~ft/npe>

compiling on Windows
---

Clone the repository, then open `moonfish.vcxproj` with Visual Studio.

- Only moonfish itself will be compiled, not its tools.
- [MinGW] may be used instead. (This way, the tools may be compiled too.)
- You may use a GUI like [cutechess] to try it.

[cutechess]: <https://github.com/cutechess/cutechess>
[MinGW]: <https://mingw-w64.org>

porting moonfish
---

Porting moonfish to a different platform should be a matter of simply providing a “mostly C89‐compliant” C implementation. Of course, moonfish doesn’t make use of *all* C89 features, so it is not necessary to have features that it doesn’t use. For example, [compiling on 9front](#compiling-on-9front) works through NPE, which provides something close enough to C89 for moonfish to work.

It is possible to compile moonfish within a strict C89 implementation by defining the `moonfish_no_threads` and `moonfish_no_clock` macros.

license
---

moonfish is released under [the 0BSD license][0BSD]:

> Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted.
>
> THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

[0BSD]: <https://landley.net/toybox/license.html>