It's a very clever aspiration to devise a new language not as something you hope everyone is going to switch to, but, as the OP states more of a test-bed to demonstrate a bunch of nice features, which you hope other people (that implement mainstream languages) will borrow/steal/copy. For instance, I very much appreciate the automatic parsing of command line arguments (and beyond just strings), which I hope the Rust folks will take over one day. Who would not like to skip all the boiler plate writing, but still offer decent cmd line options? For that reason, I will not compare the current Tomo feature set with any other language (as many other commenters do). But I will say that 150 lines for a complete terminal "snakes" game is pretty cool!

It's also smart to facilitate integration with C or other languages that have an abundance of libraries, because it's unlikely that you will create the momentum to rewrite everything in your facorite baby language.

For CLI arguments, have you checked out clap? It's declarative (you create and annotate a struct, it generates the parser), and can be agremented with man page generation or shell completion generation.

And as a result of the parsing step, you get a fully typed struct