Rocky is an XBoard compatible chess engine written in the Roc programming language.
Rocky is currently available for Linux and macOS.
Download the latest release for your OS from the GitHub
releases page,
and unzip it in a directory of your choice, for example ~/rocky.
Edit the XBoard resource file ~/.xboardrc and add a new line to the option -firstChessProgramNames, like this:
"Rocky" -fcp ./rocky -fd ~/rocky
Rocky is still in an early stage, and is currently very weak. It has no opening book, limited depth search, no time management, and limited positional knowledge. Over time, some of these things will hopefully improve.