nlnetlabs/roto — reverse-engineered prompt

Build me a Rust library called Roto. I want it to be an embedded scripting language that Rust apps can load and run, not a standalone web app. A user should be able to write small scripts with clear types, compile them before running, and then call script functions safely from Rust. Please include a simple parser and compiler flow, useful error messages with line and column info, and a few examples showing how a Rust program registers data or functions and runs a script.

Keep the first version practical and understandable. Add tests for the basic language behavior, docs that explain how to embed it, and a tiny example program I can run locally. If there are existing Roto docs or crates online, look them up and follow the current direction instead of inventing something totally different.