Lox is the language implemented in the book Crafting Interpreters by Robert Nystrom. This implementation follows the first half of the book which implements jlox (Lox written in Java), but using Rust as the implementation language instead.
If you have the executable built you can either run a program file by passing the file path as the first argument, or you can start an interactive prompt by passing no arguments.
# Running a file
$ rox ./programs/simple-program.rox
# Opening an interactive prompt
$ rox
Rox prompt, hit ctrl-d to quit.
>If you are using the Nix package manager you can run rox as a flake:
$ nix run .# ./programs/simple-program.rox
$ nix run .#
Rox prompt, hit ctrl-d to quit.
>You can also get a working development environment by running nix develop.