Recently I needed a way to pretty-print some Rust code to the command-line while building cargo-inspect.
I used syntect, but in a very crude way. It occured to me, that by using bat as a pretty-printer, I could piggy-back on what already exists and get features like line-numbers for free.
Probably other projects would want to do the same.

So I wonder if you considered providing a lib.rs, which would allow for using this crate as a library.
The main.rs, would then simply use the lib.rs as a dependency. That seems to be quite a common pattern. As an additional advantage, it would decouple the argument parsing from the rest of the code. Would that be possible?